Solid State Physics and Materials Science - Eg-MRS

THE XXVI CONFERENCE ON: Solid State Physics and Materials Science WORKSHOP ON: Nanostructures: Science, Fabrication, Characterization and Devices

10 -14 September 2006 Alexandria, Egypt

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The Egyptian Materials Research Society (Eg-MRS)

Arab Academy for Science, Technology

& Maritime Transport

Eg-MRS 2006

THE XXVI CONFERENCE Solid State Physics

and Materials Science

WORKSHOP Nanostructures:

Science, Fabrication, Characterization and Devices

SEMINAR Pre-University

Science Education

10 -14 September 2006



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TTHHEE CCOONNFFEERREENNCCEE

IISS HHEELLDD UUNNDDEERR TTHHEE AAUUSSPPIICCEESS OOFF

H. E. Prof. Dr. Yousry El-Gamal Minister of Education

Prof. Dr. Gamal Mokhtar

President, Arab Academy for

Science, Technology & Maritime Transport

Honorary Chairmanship

Prof. Dr. Raafat K. Wasef Cairo University

Prof. Dr. Omar Abd El-Aziz

Arab Academy for Science, Technology & Maritime Transport



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Sponsored by: • Acadmy of Scientific Research & Technology, Egypt. • Max-Planck-Institute, Stuttgart, Germany.



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Contents



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Conference Board….…………………..…….………………… Mailing Adress ................................................................... Objectives ………………………………………………………. Opening Ceremony ……………………………………………. Invited Speakers ………….………..…………………............ Time Table …………………….…………………………..……. Informations ……………………………………………….…… Program……………………………………………………….….. Plenary Lecture) Nanoscale Physics. Hanns-Ulrich Habermeier (Hab)...................... L 1) Magnetic Nanostructures in the Lateral and

Perpendicular Direction Hartmut Zabel (Zbl) ............................................ L 2) Semiconductor Nanoparticles-Based Gas Sensors For

Cost-Effective Air Quality Monitoring Micro-Stations Marie-Isabelle Baraton (Bar) …………………….

L 3) Engineering of Mltifunctional Nanoparticles for Biomedical Applications

Mamoun Muhammed (Muh)………………......... L 4) Effect of the Shell on the Blinking Statistics of Single

Core-Shell Quantum Dots Colin D. Heyes (Hey)……………………………..

L 5) On the Design of Ordered Metal Oxide Nanoarrays from Aqueous Solutions

Lionel Vayssieres (Vay)………………………… L 6) Optical and Electronic Properties of Small Size Silicon and

Silicon-based Nanostructures Aristides D. Zdetsis (Zdt)………………………..

L 7) Self-Assembled Nanostructured Oxides Abdelkrim Chemseddine (Chn)…………………

L 8) Synthesizing of Nanomaterials and Nanocompositrs Powder by Mechanically-Induced-Solid-State Reaction and Subsequent Consolidation

M. Sherif El-Eskandarany (Esk) ………………. L 9) Oxide Interfaces – Is There Novel Materials Physics

Emerging ? Hanns-Ulrich Habermeier (Hab)........................

8 9 10 11 13 30 31 41 47 48

50 52 54 56 57

58 59 61



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L10) Ultrafast Optical Response of Semicondcutor

Nanocrystals Mona Bakr Mohamed (Mon)………………….

L11) Magnetic Properties of Spintronic Materials Hartmut Zabel (Zbl)……………………………

L12) Protein Folding Studied by Single Molecule Fluorescence Resonance Energy Transfer

Colin D. Heyes (Hey) …………………………

L13) On the Aqueous Thermodynamic Stability of Metal Oxide Nanoparticles

Lionel Vayssieres (Vay)……………………….

Oral Presentations Session A................................................................................. Session B................................................................................. Session C................................................................................. Session D................................................................................. Session E................................................................................. Session F................................................................................. Session G................................................................................. Session H.................................................................................

Posters Presentations

62 63 65 67 69 85 99

111121137147159

169



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Conference Chairman: Prof. Dr. Kamal Abd El-Hady Minia University Conference Co-Chairman: Prof. Dr. Fakhry Abd El-Salam Ain Shams University Prof. Dr. Abdelrazek Y. Kandeil AASTMT Workshop International Organize: Prof. Dr. Hanns-Ulrich Habermeier Max-Planck-Institut,

Stuttgart Workshop Chairman: Prof. Dr. M. Hassan Talaat Ain Shams University Workshop Co-Chairman: Prof. Dr. Ahmed A. Ramadan Helwan University Organizing Committee: Prof. Dr. Fayez Shahin Beni-Suef University Prof. Dr. Hassan Afify NRC, Cairo Prof. Dr. Hesham M. Talaat Al-Azhar University Prof. Dr. Mohamed El-Okr Al-Azhar University Prof. Dr. Sherif A. Khairy Cairo University Local Organizing Committee: Prof. Dr. Osama El-Shazly Alexandria University Eng. Mahmoud Morsi AASTMT Dr. Fathi Ibrahim AASTMT Dr. Moataz Soliman ASMS

BOARD



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All correspondances should be addressed to: The Egyptian Materials Research Society (Eg-MRS),

33 Abdel-Khalik Tharwat Street, Cairo, Egypt.

Telephone/Fax: +202-3925997 (Sunday & Wednesday, 6-10 pm)

E-mail: [email protected] Web: http: //www.egmrs.org

MAILING ADDRESS



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Objectives The aim of the conference is to provide a forum for exchange of knowledge in

the high interdisciplinary fields of solid state physics and materials science as well as to bring together scientists working in academic and applied research areas for constructive interactions.

The topics to be covered are: * Semiconductor physics and devices. * Metal and Polymer Physics. * Superconductivity. * Thin films and Surface Physics.. * Optoelectronic Materials. * Solar Energy Materials and Devices. * Magnetism and Magneto-optics. * Crystallography and Amorphography. * Spectroscopy and Optical Properties.

Nanoscale science and technology, where length scale comparable to atoms

and molecules, modify and control macroscopic properties of material through quantum effect. As the size approaches the nanoscale level, dimensions play a critical role and many distinctive and potentially useful phenomena and properties emerge. The lectures include physics at nanoscale, fabrication of nanostructured materials and nanotechnology of devices as well as modification of optical, electric, magnetic and chemical properties. Also, fundamental size-dependent phenomena and developed applications to semiconductor, optical devices and phononic crystals will be presented.

School-University-Research is a correlated series, the first strongly affects the next two. So, the subject of teaching physics in pre-university education will be discussed by university professors and leaders of education in Alexandria Governorate.

CONFERENCE

WORKSHOP

SEMINAR



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Opening Ceremony Prof. Dr. Omar Abd El-Aziz,

Vice-President for Education, Arab Academy for Science, Technology & Maritime Transport.

Prof. Dr. Kamal Abd El-Hady,

Chairman of Eg-MRS & Conference.

Prof. Dr. Hassan Talaat, Chairman of Workshop.

Prof. Dr. Hanns-Ulrich Habermeier, Workshop International Organizer.

Prof. Dr. Gamal Mokhtar, President, Arab Academy for Science,

Technology & Maritime Transport.

H. E. Prof. Dr. Yousry El-Gamal, Minister of Education.



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Prof. Dr. Marie-Isabelle Baraton (Bar) Ph.D; D.Sc.; Habil. Department of Ceramics, Faculty of Sciences, SPCTS - UMR CNRS 6638, University of Limoges, 123 Avenue Albert Thomas, F-87060 Limoges, France. Tel: +33 680 63 2031 Fax: +33 555 77 8100 E-mail: [email protected] [email protected]

Biography

• Senior scientist in the Department of Ceramics (SPCTS, UMR

CNRS), leading research on nanostructured materials at the University of Limoges, France where she received her Ph.D. in physics and her Doctorate in Science.

• Obtained a NATO grant to conduct fundamental research on infrared surface characterization of nanosized powders and on Langmuir-Blodget films at the University of Ottawa, and at the Lash Miller Laboratories in Toronto, Canada.

• Current research interests include the physical-chemistry of nanomaterial surfaces as well as theoretical and experimental studies of chemical reactions at gas-nanomaterials interfaces.

• Authored over 200 refereed papers, communications and book chapters. She has given invited lectures and seminars in Europe, the USA, Russia and NIS, Japan, India, China, Australia among other countries. She is the editor of several books on nanomaterials including a recently published book on functionalization of nanoparticles.

• Initiator and the coordinator of two European projects (FP4 and FP5). She led the two European Consortia comprising industries, research centers and universities working on novel gas sensors based on semiconductor nanomaterials for air quality monitoring.



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• Founder and the President of a private research center CERAMEC dedicated to the applications of nanomaterials.

• Organized international conferences on nanomaterials and she was one of the three Meeting Chairs of the Fall 2002 Materials Research Society (MRS) meeting in Boston (MA, USA). In 2000, she was the director for NATO countries of an Advanced Study Institute on functional gradient materials, sponsored by NATO. Again as director for NATO countries, she is organizing another Advanced Study Institute on sensors for environment, health and security (to be held in 2007).

• Vice-chair of the COST Action D19. She is expert-evaluator for the European Commission under FP5 and FP6. She is a member of the Expert Advisory Group (Thematic Priority 3 “Nanotechnology, Materials and Products”) for FP6 (2002-2006) and FP7 (2007-2013) of the European Commission. In the USA, she chaired the MRS International Relations Committee in 2003 and she has been elected member of the MRS Board of Directors.



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• Dr. Abdelkrim Chemseddine (Chm) Solarenergieforschung, Hahn-Meitner-Institut, Glienicker Str. 100 . 14109 Berlin, Germany. Phone: FAX: E-mail: [email protected]

Biography

• Current Position: Staff Scientist. • Received his education at the University of Pierre et Marie

Curie, ParisVI, France. • M.Sc degree in Spectrochemistry and structure (1981). • “doctorat de 3ème cycle in chemistry of isopolytungstates”

(1983) and doctorat d´etat on the sol-gel chemistry of tungsten oxide (1986).

• Worked as a research associate at the Material Science and Enginnering Department, University of California Los Angeles with Professor J.D. Mackentie (1986-1987).

• As an Alexander von Humboldt Foundation guest scientist he worked at the University Ludwig Maximilian in Munich on surface chemistry and photocatalysis with professor H.P. Boehm(1987-89).

• Spent one year teaching as a professor of chemistry at the university Hassa II, Faculty of Science, Morocco.

• As a guest scientist he worked at the Hahn_Meitner-Institut on the sol-gel processing of highly porous semiconductor oxide films.

• Since 1991 he became a permanent scientist working in the field of nanocrystals.

• In1997, he spent 4 months as a visiting professor teaching the chemistry of nanocrystals and nanostructrured materials at Georgia Institute of Technology.



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• Present Research One of the challenging objectives in research on next-generation materials is the structural control at all hierarchies of organization ranging from material texture to the level of atomic structure. Dr. Chemseddine research toward this objectiv is concerned with the developement of new wet chemical approaches to generate nanoclusters and nanocrystallites as intermediate building block for extended solid. Effort is devoted to an understanding of fundamental details which relate chemical reactivity to nucleation, growth and surface restructuration processes of condensed phases. This will enable create the physico-chemical conditions for the synthesis and processing of nanocrystals with desired size, shape, core structure and well defined surface.Furthermore, this research is taking advantage of different interactions, which may exist in the nanosize regime, between inorganic cores, capping ligands and solvents to generate well defined architectures, by self-assembly from suitably designed and functionalized nanocrystals.

• Selected Publications: 1. “Electrochemical and Photochemical Reduction of

Decatungstate a Reinvestigation”, A. Chemseddine, C. Sanchez, J. Livage, J.P. Launay, M. Fournier, Inorg. Chem., 23 (1984) 2609.

2. “A Study of the Primary Step in the Photochemical Degradation of Acetic and Chloroacetic Acid on a TiO2 Photocatalyst”, A. Chemseddine, H.P. Boehm, J. Molec. Catalysis., 60 (1990) 295-311.

3. “Fibrous, Oriented and Pure Quantum Dots: Synthesis and Characterization”, A. Chemseddine Chemical Physics Letters, 216 (1993) 265.

4. “Investigation of the Nanocluster Self-Assembly Process by Scanning Tunneling Microscopy and Optical Spectroscopy”, A. Chemseddine, H. Jungblut, S. Boulmaaz J. Phys. Chem. 100 (1996) 12546.



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5. “Nanostructured Crystalline TIO2 Through Groth Control and Stabilization of Intermediate Structural Bulding Units” T. Moritz, J. Reiss, K. Diesner, D. Su., A. Chemseddine J. Phys. Chem 101(1997) 8053.

6. “Nanostructuring Titania: Control over Nanocrystal Structure, Size, Shape and Organization” A. Chemseddine, T. Moritz Eur. J. Inorg. Chem. (1999) 235-245.

7. “Meal-Oxide and –Sulfide Nanocrystals and Nanostructure” in (CHARACTERIAZTION OF NANOPHASES MATERIALS), A. Chemseddine, Chap.11, pp315-352 Edited by Z.L. Wang, Wiley-VCH Verlag, 2000.

8. “Enhanced CH-217EMICAL Reactivity of Tris-(2,2´-Bipyridyl)Ruthenium (II) Complex Due to Eectrostatic Binding to Colloidal Particles as Evidence on the Basis of the Reaction with Azidyl Radicals”, A. Eckhart, A. Chemseddine, T. Moritz, D.B. Naik, W. Schnabel. Phys. Chem. Chem. Phys., 2001, 3, 213.

9. Revised Superconducting Phase Diagramm of Hole-Doped Nax(H3O)zCo2.2H2O”, C.J. Milne, D. N. Argyriou, A. Chemseddine, N. Aliouane, J. Veira, S. Landesgesell, D. Alber . Phys. Rev. Latt. 93 (2004) 247007

10. “Crystal Structure of the Superconducting Layered Cobaltate NaxCoO2.yD2O”, D.N. Argyriou, P.G. Radaelli, C.J. Milne, N. Aliouane, L.C. Chapon, A. Chemseddine, J. Veira, S. Cox, N.D. Mathue, P.A. Midgley. J. Phys.: Condens. Matter 17 (2005) 3293-3304



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• Prof. Dr. Eng. M. Sherif El-Eskandarany (Esk) Technology Development & Scientific Services Sector, Academy of Scientific Research & Technology, 101 Kasr Al-Aini Street, Cairo 11516, Egypt. Tel/Fax : +(202) 7953 785 E-mail: [email protected] [email protected] Web: http:/www.eleskandarany.com

Biography

Date of Birth: September 12th, 1956 Cairo, Egypt EDUCATION: June 1981 University Degree of Mining and Metallurgical

Engineering, Faculty of Engineering, Al-Azhar University, Cairo, Egypt.

March 1988 Master Degree of Engineering (Metallurgy), Institute of Mineral Dressing and Metallurgy, Tohoku University, Japan.

March 1992 Doctor Degree of Engineering (Materials Science), Institute for Materials Research, Tohoku University, Japan.

PROFESSIONAL EMPLOYMENT: December 1981 - September 1985

Asst. Prof., Mining and Petroleum Engineering Dept., Fac. of Engineering, Al-Azhar University, Cairo, Egypt.

April 1992 - September 1992

Asst. Prof., working with Professor Kenji Suzuki, Inst. for Materials Research, Tohoku University, Japan.



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January 1993 - September 1997

Lecturer of Materials Science and Metallurgy, Mining and Petroleum Engineering Dept., Fac. of Engineering, Al-Azhar University, Cairo, Egypt.

July 1995 - June 1997

Visiting Professor, working with Prof. Kenji Suzuki, Inst. for Materials Research, Tohoku University, Japan.

March 1998 Asst. Prof. of Materials Science and Metallurgy, Mining and Petroleum Engineering Dept, Fac. of Engineering, Al-Azhar University, Cairo, Egypt.

September 2000

Visiting Professor at Inoue SuperLiquid Glass Project, Japan Science and Technology Corporation, Exploratory Research for Advanced Materials, Japan.

August 2002 Associate Professor of Materials Science and Metallurgy, working at Mining and Petroleum Engineering Dept., Fac. of Engineering, Al-Azhar University, Cairo, Egypt.

April 2003 Professor of Materials Science and Metallurgy, Mining and Petroleum Engineering Dept., Fac. of Engineering, Al-Azhar University, Cairo, Egypt.

December 2005 to Present

Vice-President of Academy of Scientific Research & Technology, for Technology Development & Scientific Services Sector, Ministry of Higher Education and Scientific Research

ORGANIZATIONS:

1988 Japan Society of Metals, JIM. 1989 Materials Research Society, MRS (USA). 1990 Japan Society of Powder and Powder Metallurgy,

JSPM. 1994 The New York Academy of Science (USA). 1995 The Planetary Society (USA). 1996 American Association for the Advancement of

Science, AAAS (USA). 1996 The Minerals, Metals and Materials Society, TMS

(USA).



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PRIZES AND AWARDS: June 1993 National Prize of Engineering Science, Egyptian

Academy of Scientific Researches and Technology. May 1995 Golden Medal of Excellence, Egyptian President. May 1997 Research Prize of Applied Science Engineering and

Technology, Japan Society of Powder and Powder Metallurgy.

June 2002 National Prize of Engineering Science, Egyptian Academy of Scientific Researches and Technology.

April 2006 Research Prize of Engineering, Al-Azhar University PUBLICATIONS:

• Research Articles Published in International Journals 111 papers

• Published books and book chapters at international presses 3 books and 3 book chapters

MAJOR ACHIEVEMENTS AND RESEARCH INTEREST: Has been dealing with the fabrication and characterizations of

new families of advanced materials, which find interesting and important engineering applications. Within the last two decades he could introduced more than

twenty types of these materials that have pioneering advanced properties, using the mechanical alloying way of fabrication. New metallic glasses, new ceramics, nanocrystalline and

nanocomposite materials, equilibrium and nonequilibrium, metallic nitrides, hydrides and carbides have been fabricated at the Fac. of Engineering of Al Azhar University in Egypt. Amorphous AlTa capacitors and condensers, nonequilibrium

superconducting NbN and ZrN, materials nanocrystalline TiC, WC, composite WC/MgO and WC/Co cutting tools hard materials, nanocomposite materials of Al, Mg-based, nanocrystalline TiN coating materials, metallic glassy Zr-based, Cu-based, V-based, Nb-base, Ta-based fully dense alloys, are some of those materials that have been fabricated by the nominee. These advanced materials, which cannot be produced by the traditional way of



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melting and casting techniques, are finding now very important and useful engineering applications. Has established his school for fabrication of the advanced

materials in Egypt. He is the leading authority on mechanical alloying. He shared the developing program of new materials at Inoue

Super Liquid Glass Project, Institute for Materials Research, Tohoku University of Japan. He was invited to work as a Group Leader for R&D of selected

advanced materials (nanocrystalline and nanocomposite materials) at The Institute for Advanced Technology and Advanced Materials, Mubarak City for Scientific Research and Technology Applications, Alexandria, Egypt. He is the referee for many International Research Journals, such

as, Journal of Materials Research (MRS, U.S.A.), Metallurgical Transactions (TMS, U.S.A.), Journal of Alloys and Compounds (Elsevier, Holland/Oxford) and also for many national engineering scientific journals. He is a scientific reviewer and advisor of the course for special

theoretical training of the structural materials, EGYPTSAT-1 SATELLITE PROJEC, Egypt Sat Space Program, Cairo-Egypt. In addition, he is a national reviewer of some projects submitted to the Academy of Scientific & Technology, Cairo, Egypt.



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• Prof. Dr. Hanns-Ulrich Habermeier (Hab) Max-Planck-Institut für Festkrperforschung, Heisenbergstr. 1, D 70569 Stuttgart, Germany. Phone: +49-711-689-1372 FAX: +49-711-689-1389 E-mail: [email protected]

•

Biography

• Received his Ph. D. from University Stuttgart, Germany, 1974. • Worked as a staff member at the University Stuttgart/Max-

Planck-Institut for Metal Research, Stuttgart from 1974 through 1977 in the field of flux pinning in super-conductors.

• Joined the IBM Thomas Watson Research Laboratory, Yorktown Heights, N.Y.,U.S.A. 1978-79 focusing his interest on quantum localization and A–15 super-conducting thin films.

• Appointed to be the Head of the Technology Group at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany 1980.

• His interests covered the area of process-induced defects in semiconductors, semiconductor process technology. Starting with the discovery of cuprate superconductors his interest shifted towards thin film physics and thin film technology of functional ceramics.

• Since 1997 he is Honorary Professor and Member of Faculty of Yunnan Polytechnic University, Kunming, P.R. Of China and since 2000 Honorary Professor and Member of Faculty of Kunming University of Science and Technology [ KUST ] P.R. of China. Furthermore,

• Member of the Executive Committee of EMRS since 1995 and served as E-MRS Vice President / President 1996-99 and as Treasurer of IUMRS 2000-2002. Additionally, he is the Secretary of the European Society for Applied Superconductivity [ ESAS ] since 2000.



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• Dr. Colin Heyes (Hey) Department of Biophysics, University of Ulm, Albert Einstein Allee 11, 89069 Ulm, Germany. E-mail: [email protected]

Biography

• Received the Balchelor of Science degree in chemistry in 1997

from Loughborough University in the U.K. • Joined the group of Mostafa El-Sayed at the Georgia Institute of

Technology, Atlanta, USA, in 1997 to undertake a Ph. D. in physical chemistry.

• The Ph. D. thesis was concerned with spectroscopic investigations of membrane protein structure, function and stability. The Ph. D. was awarded in 2002.

• Went to Ulm to work in the group of Professor Uli Nienhaus after being awarded postdoctoral fellowships from the Alexander von Humboldt (AvH) foundation and the Human Frontiers Science Program (HFSP).

• In Ulm, the research has focused on measuring the structure and folding pathways of single protein molecules using fluorescence microscopy as well as developing novel fluorescent probes, such as fluorescent inorganic nanoparticles, for biophysics and life science research. This latter project involves studying the photophysics of quantum confined systems, especially the single molecule fluorescence blinking phenomenon of core-shell quantum dots, as well as methods to render them water-soluble and biocomatible.

• The co-principal investigator of a project in the Sonderforschungsbereich (SFB) 569 interdiciplinary research grant which aims to conjugate these nanomaterials to biomolecules to form biological-templated nanostructures at the exciting interface of nanotechnology and biotechnology.



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• Dr. Mona Bakr Mohamed (Mon) National Institute of Laser Enhanced Science, Cairo University, Geza, Egypt. Email:

Biography

• B. SC. 1991 & M.SC, 1994 in Chemistry from Assiut University, Egypt. Ph.D from Georgia Tech, Atlanta, USA 2002 under supervision of Prof. Mostafa El-Sayed.

• Research Scientist in EPFL Switzerland (2002-2005). • Currently, Lecture at National Institute of Laser Enhanced

Science, Cairo University. • Her research interest is focused in synthesis and characterization

of metallic and semiconductor nanocrystals of different shape and size, as well as studying their optical properties and ultrafast dynamics using different laser techniques.

• She has 28 publications published in international journals such as J. Phys. Chem, Physical Rev., Nanoletters, Chemical phys. Letters,….



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• Prof. Dr. Mamoun Muhammed (Muh) Royal Institute of Technology, SE-100 44 Stockholm, Sweden. Phone: +468-790 8158 Fax: +468-7909072 Mobile: +467 0558 8158 Email: [email protected]

Biography - Personal Data • Date and Place of Birth: 24 Sep 1944, Cairo, Egypt • Martial Status: Married, Two daughters • Nationality: Egyptian, Swedish • Home address: Eketorpsvägen 25, SE-182 61

Djursholm (Stockholm) Sweden. - Current Position: • Professor and Director of Materials Chemistry Division. • Director International Master’s Programme on Nanomaterials and

Nanotechnology. - Professional Preparation, Academic Degrees:

1984: D. Sc., (Docent), Royal Institute of Technology, Stockholm, Sweden.

1975: Ph. D., Royal Institute of Technology, Stockholm, Sweden.

1967: B.Sc. Chemistry, Ain-Shams University, Cairo University, Egypt.

1965: B.Sc. Soil Sciences, Ain-Shams University, Cairo University, Egypt.

- Appointments: • Professor and Head of Materials Chemistry Division at Royal

Institute of Technology. • Chairman, International Committee on Nanostructured

Materials. • Chairman of the steering Committee for Nordic Nanotechnology

Programme, Nordic Industrial foundation. • Director of the International Master’s Program on Nanomaterials

& Nanotechnology, KTH



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• Director of the Graduate Studies, Department of Materials Science & Engineering, KTH

• Member of the Board (elected), Dept of Materials Science and Engineering, KTH since 1998

• Member of the Appointment Committee, Faculty of Materials & Mechanical Engineering, KTH, since 2001

• He has been with the Royal Institute of Technology since 1969 at different positions, and has been serving on several committees (commissions of trust) at this university.

• Dr. Muhammed has been a visiting professor in Spain, Italy, Korea, and Egypt, and he is active in several national and international organisations.

- Scientific Contributions: • Dr. Muhammed has published over 200 papers, Co-edited one

book and has been a guest editor to two special volumes in the Nanostructured Materials Journal.

• He has more than 200 conference and seminars presentations of which more than 50 are invited lectures,

• Has more than 20 patents and patent applications where several of them have been filed at different European countries and USA.

• Dr. Muhammed’s group is about 15-20 persons and has been funded via external grants from National, European, and International agencies as well as industrial companies. (EU, DARPA-USA, Degussa-Germany, KICET-Korea, …)

• Has supervised more than 35 Theses (Master, Licentiate, and Ph.D)

- Other Appointments and Commissions of trust: • Vice Chairman, International Committee on Nanostructured

Materials (2003-2005) • Member of the Board for Centre for Nano- and Micro

technology KTH-KI. 2002- • Member of the Board for Powder Technology Centre, and

Consortium for Clusters and Ultra-fine particles (1990-2000). • Coordinator of EU- project Nanothermel programme with 10

partners from six different countries. • Invited to lecturer by several Academies; Swedish Royal

Academy of Engineering Science, Royal Spanish Academy, Academica Sinica (Chinese Academy), Egyptian Academy of Science and Technology.

• Expert for evaluating research programs for Finish Academy, Estonia Accreditation Board and the European Commission, Science and Technology Directorate, Ireland Science and Technology Foundation, Singapore Science and Technology Foundation.



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• Expert for evaluation and Accreditation of Estonian programmes on Materials and Chemistry at Tallinn University and Tartu University.

• Chairman, organizer of several international Conference and symposia (4th International conference of Nanophase Materials, Nano 98, Stockholm, American Chemical Society Symposium on Modelling of Speciation, San Francisco, March 2000), Nanoparticles, MRS Annual Meeting, Nov 2001, 98, Clusters and Ultarfine particles Stockholm, 1993)

• Expert for the Evaluation for Chair in Materials Science, Luleå University of Technology, 2004.

• Acts as referee for numerous scientific journals. • Associated editor on several scientific journals, e.g., Nano-

Structured Materials journal and on the Editorial Board for Solvent Extraction and Ion Exchange, J. European Mineral Processing and Environmental Protection., J. Korean Ceramic Society.

• Has been teaching materials science, chemistry and metallurgy students and has given several courses at universities in Spain, Italy, Albania and Egypt.

• Has been a team member in several EU funded projects • Examiner, Chairman, and member of the examination

committees, for several Ph.D. and Licentiate, and Master Theses, in Sweden, Norway, Spain, Egypt, India, etc.

- Entrepreneurial • Has more than 20 patents and patent applications; several of

them have been filed at European countries and USA. • Has developed three processes which have been evaluated in

a scaled up pilot testing. • Established SME NanoChem Technologies, and a co-founder

of Nano Biomedical Technology AB, for the industrial exploitation of the research results on Nanomaterials in medical applications.

• Acted as a consultant for several European and USA companies.

- Publications A. Books • Singh, R.K., Hofmann, H., Senna, M., Partch, R., Muhammed,

M. (Eds.), “Nanoparticulate Materials”, Eds. Mat. Res. Soc. V704, 2001, Nov. 26-29.

• Muhammed, M. and K. V. Rao, (Guest Editors), “Nanostructured Materials”, Special Volume, 4th International Conference on Nanostructured Materials, (NANO 98), Part A. Vol 12, No. 1-4 (1-600) 1999.



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• Muhammed, M. and K. V. Rao, (Guest Editors), “Nanostructured Materials, Special Volume, 4th International Conference on Nanostructured Materials, (NANO 98), Part B. Vol 12, No. 5-8 (601-1188) 1999.

B. Reviews • Muhammed, M., “Nanostructures: Synthesis, Functional

Properties and Applications”; T. Tsakalakos et al. (Eds) Kluwer Academic Publishers, 2003, 37-79

• Muhammed, M., Tsakalakos, T., “Nanostructured Materials and Nanotechnology: Overview”, J. Korean Ceram. Soc. 40 (11), 2003, 1027-1046 (*)

• Muhammed, M. and Toprak, M., “Thermoelectrics Handbook: Macro to Nano-Structured Materials”; Chapter_41, Nansotructured Skutterudites, In Press.

- Patents 1. Method of preparing powders for hard materials from cobalt

salts and soluble tungstate salts. Grenthe. I; Muhammed, M. and Wahlberg, S. Swedish Patent 504 730 (1997), US Patent 5,632,824 (1997).

2. Method of preparing powders for hard materials Muhammed. M.; Wahlberg, S. and Grenthe, I., US Patent 5,594,929 (1997), European Patent EP 0 686 704 B1(1998).

3. Method and apparatus for the production of nanoparticles. Muhammed, M. and Wang, L. Swedish Patent application 9803572-8 (1998).

4. Manufacture of nano-engineered precursors for superconductors. Muhammed, Mamoun; Zhang, Yu; Wang, Lingna, PCT Int. Appl. (2000), WO 2000051948, A1 20000908.

5. Enhancement of boiling heat transfer by Nanofluid. Mohammad, Zhang, Toprak, Witharana, Palm, Swedish Patent Application 0301262-2 (2003).

6. Oxygen storage material, process for its preparation and its application in a catalyst. Bog, Tassilo; Mussmann, Lothar; Lindner, Dieter; Votsmeier, Martin; Feger, Matthias; Lox, Egbert; Kreuzer, Thomas; Muhammed, Mamoun; Adamopoulos, Othon. (OMG AG & Co. KG, Germany), U.S. Pat. Appl. Publ. (2004), US 2004186016, A1 20040923



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7. Engineering of Porous Surfaces for Enhanced Boiling. M. Toprak, S. Li, Y. Zhang, M. Muhammed, R. Furberg, B. Palm (Submitted to the Swedish Patent Office).



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• Dr. Lionel Vayssieres (Vay) National Institute for Materials Science, International Center for Young Scientists, Japan. E-mail: [email protected] Web: http://www.inderscience.com/ijnt

Biography

o Born in 1968. o Obtained a M. Sc. in Physical Chemistry in 1991 and a Ph.D. in

Inorganic Chemistry in November 1995 from the Université Pierre et Marie Curie in Paris, France for his research work on the Interfacial and thermodynamic growth control of metal oxide nanoparticles in aqueous solutions. Thereafter, he joined Uppsala University, Sweden as a postdoctoral researcher for the Swedish Materials Consortium on Clusters and Ultrafine Particles to extend his concepts and develop purpose-built metal oxide nanomaterials for photoelectrochemical applications as well as to characterize their electronic structure by X-ray spectroscopies at synchrotron radiation facilities. :

o Invited as a visiting scientist: at the department of Chemical Engineering at the University of Texas at Austin, USA on nanocomposite metallic oxides for biosensors, at the UNESCO Centre for Macromolecules & Materials and at the department of Biochemistry, at Stellenbosch University, South Africa on bio-nanocomposite materials, at the Glenn T. Seaborg Center, Chemical Sciences Division, at Lawrence Berkeley National Laboratory, USA on actinide nanomaterials, at the Texas Materials Institute on metal oxide-based nanomaterials for optical, magnetic, and energy storage and conversion devices, and at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland on metal oxide oriented arrays for photocatalytic devices.



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• Co-authored 50 refereed publications, 3 ISI highly cited papers for the last 10 years, #1 in the Top 10 hot papers published in the last 2 years in Chemistry (Jul-Aug 05), #2 in the Top 3 hot papers published in the last 2 years in Materials Science (Sep-Dec 05) and #3 (May-June 05) in major international journals, refereed proceedings and book series, which have generated about 1000 citations (1 paper over 200 citations, 2 over 100, 3 over 50). He has presented over 100 lectures at universities, research institutes and international conferences as well as acting as session chairman, program committee and advisory member at major conferences and projects worldwide.

• Currently a senior research scientist at the International Center

for Young Scientists, National Institute for Materials Science (NIMS) in Tsukuba, Japan; a R&D consultant for Hydrogen Solar Ltd., UK; a guest scientist at the Chemical Sciences Division and the Advanced Light Source at Lawrence Berkeley National Laboratory, USA as well as at the Materials Chemistry Department at Ångström Laboratory, Uppsala University, Sweden. He is the conference chairman of the first symposium dedicated to Solar Hydrogen & Nanotechnology organized by the International Society for Optical Engineering to be held at the convention center in San Diego, CA USA August 13-17, 2006 during the SPIE 2006 Optics & Photonics meeting. He is also the founder and editor-in-chief of a new journal dedicated to reviews in nanotechnology and related fields, the International Journal of Nanotechnology published by Inderscience Entreprises Ltd.



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• Prof. Dr. Hartmut Zabel (Zbl) Department of Physics, Faculty of Physics and Astronomie, Ruhr-Universität Bochum, D-44780 Bochum, Germany. Phone: xx49-234-322.3649/50 E-mail: [email protected]

[email protected] Web: www.ep4.rub.de

Biography • Date of birth:

21.03.1946 • Academic title:

Professor Dr. rer. rat. Dr. h.c. Chair of Experimental Physics/Condensed Matter Physics.

• Education/Degrees: 1969 Vordiplom in Physics, University of Bonn. 1973 Hauptdiplom in Physics, Technical University of Munich. 1978 Ph.D. in Physics (summa cum laude), University of Munich.

• Academic Positions: 1978 - 1979 Postdoctoral Fellow, Department of Physics, University of Houston, Texas. 1979 - 1983 Assistant Professor of Physics, University of Illinois at Urbana – Champaign. 1983 - 1986 Associate Professor of Physics, University of Illinois at U-C. 1986 - 1989 Professor of Physics, University of Illinois at U-C. since 1.4.1989 Chair, Prof. of Experimental Physics/cond. Matter Physics, Ruhr-Universit.t Bochum. since 1.4.1989 Adjunct Professor of Physics, University of Illinois at U-C.



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• Scientific honors: 1971 - 1973 Fellow of the Cusanus Studienstiftung. 1982 Fellow of the Institute for Advanced Studies, Univ. of Illinois at Urbana-Champaign. 1989 Fellow of the Japanese Society for the Promotion of Sciences. 1993 + 1997 Fellow of the Volkswagenstiftung. Since 1996 Election to Fellow of the American Physical Society. 2001 Honor Doctor of the Kings Technical University (KTH) Stockholm.

• Professional activities: 1986 - 1989 Department of Energy (DOE) Program Director in the Materials Research Laboratory for the Condensed Matter Science Program 1992 - 2002 Chair, German – Russian Collaboration "Advanced Materials with Collective Electronic Properties", funded through the DFG the Russian Academy of Science. 1991 – 1998 Vice-Chair of the SFB 166 “Struktur, „Transport and Phasenüberg.nge an komplexen Oberfl.chen und Grenzfl.chen Oxide, Carbide, Nitride“ 1993-1995 Chairman of the Department of Physics and Astronomy, Ruhr-Universit.t Bochum 1997 - 1999 Member and Chair, Subcommittee: Materials Science, Surfaces & Spectroscopy committee at the Institute Laue-Langevin, Grenoble, France 1997 – pres. Scientific Advisor for the German-Israeli Foundation (GIF) for Sc. R and D. 1999 – pres. Member of the Arbeitskreis “Magnetism” of the German Physical Society. 2000 – pres. Chairman of the SFB491 “Magnetic Heterostructures” 6/2003 – Chairman of the Scientific Council of the Swiss Intense Neutron Source (SINQ) Since 2003 Editor of the Journal: Superlattices and Microstructures, Elsevier . 2005 – 2008 Chairperson of the committee “Exploration of Condensed Matter with Large Scale Facilities“.



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• Organization of International Conferences: 1991 Intern. Conf. "Surface X-Ray and Neutron Scattering", Bad Honnef, Germany. 1999 Intern. workshop: “Nanomagnetic Materials”, Bad Honnef, Germany, January 1999. 2001 International Conference: “Metallic Multilayers”, Aachen, Germany, June 2001.

• Memberships of Professional Societies: German Physical Society (DPG); American Physical Society, fellow; European Physical Society, Materials Research Society.

• Publications: More than 360 refereed papers in technical journals, ca 20 review papers, ed. three books.

• Active Research interests: Magnetism of thin films and heterostructures, proximity effects between superconductors and ferromagnets, hydrogen in thin metal films, X-ray and neutron scattering, magneto-optical Kerr effect.



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• Prof. Dr. Aristides D. Zdetsis (Zdt) Professor, Department of Physics Division of Theoretical and Mathematical Physics, Astronomy and Astrophysics Head of the Molecular Engineering Group University of Patras, Greece E-mail: [email protected] , [email protected]

• Current Research Interests:

Theoretical and Computational Solid States Physics and Material Sciences: Electronic, Optical and structural properties of amorphous semiconductors, clusters and nanostructures. There are more than 90 publications on these subjects in international journals and (refereed) international conference-proceedings and more than 50 presentations in Greek and international conferences (many of which are invited).

• Education:

1964 High school diploma High School of Nikaia, GR.

1969 Bachelor’s Degree

Department of Physics University of Athens, GR

1972 Master’s Degree

Thomas Jepherson University, Swarthmore College Campus -Bartol Research Foundation, Swarthmore, Pa. USA. Dissertation: A review of the shell model with reference to the O18 nucleus.

1976 Ph.D Degree Thomas Jepherson University, Swarthmore College Campus -Bartol Research Foundation, Swarthmore, Pa. USA. Dissertation: Lattice Dynamics of crystals with diamond structure.



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• Books: 1. “Quantum Physics I” (pages 550) in Greek, Hellenic Open

University (2004) 2. “Vibrations and Waves, Volumes 2, part I ” (pages 380) in

Greek, Hellenic Open University (2004) 3. “From Classical to Modern Physics” (480 pages) in Greek

(2001) 4. “Vibrations and Waves Volume2, part II. Applications:

Acoustics and Optics” (340 pages) in Greek 5. “Introduction to Modern Physics” (600 pages) in Greek ,

University of Patras (2003).

• Teaching: Solid State Physics, Quantum Mechanics, Computational Physics, Modern Physics, Mathematical methods, Statistical Physics, Classical Mechanics and Electromagnetism. Supervision in more than 20 undergraduate diploma thesis, more than 5 Master’s thesis and 5 Ph.D dissertations.

• Membership in scientific societies: American Physical Society, Sigma - Xi Society for the progress of Science (Local Chapter of Swarthmore PA and also member at large), American Association for the Advancement of Science, Greek society of Science and technology of condensed matter, Greek Society of Nano-cience and Nanotechnology.

Time Table

Sunday Sept. 10

Departure: 7:00 Naser City 7:30 Tahrir Sq.

Registration + Accommodation

OpeningCeremony

Plenary Lecture( Hab)

Seminar Seminar

Monday Sept. 11

L 1 (Zbl)

L 2 (Bar)

B r

L 3 ( Muh)

L 4 ( Hey)

Paper Session A + B

B r e Paper Session

C + D

Tuesday Sept. 12

L 5 (Vay)

L 6 (Zdt) Visits & Excursions Visits & Excursions

Wednesday Sept. 13

L 7 (Chm)

L 8 ( Esk)

L 9 ( Hab)

L10 ( Mon)

Paper Session E + F

a k

Paper Session G + H

D i n n e r

Thursday Sept. 14

L11 (Zbl)

L12 (Hey)

e a k L13

(Vay) Closing

Ceremony

L u n c h

Departure to Cairo

09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00



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Informations Breakfast:

will be served from 7:30 to 8:30.

Posters:

will be presented from 13:30 on Monday, September 11 to 17:30 on Wednesday, September 13. Social Activities:

# Excursion on Tuesday, September12: 1) National Museum. 2) Qaitbay Fort. 3) Lunch in Alexandria Downtown.

Visit (Optional):

On Sunday (Sept. 10), Monday (Sept. 11) or Wednesday (Sept. 13):

# The planetarium at Bibliotheca Alexandrina: * Time Table and price: To be announced.

Tour (Optional): On Saturday (September 09) for Historical Cairo Sites:

# Program: 1- Visits with Entrance fees: Egyptian Museum, Panorama

of Salah El-Dien Citadel (by-pass) and Giza Pyramids. 2- Lunch. 3- English Speaker Tour Guide.

4- All Transfers inside Cairo. # Price:

Group less than 4 persons : 65 USD. Group of 4 - 5 persons : 55 USD. Group more than 5 persons: 45 USD.



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Sunday, September 10 12:00 - 12:30: Opening Ceremony 12:30 - 13:30: Plenary Lecture) Education and Economy

- An Analysis of Statistical Data. Hanns-Ulrich Habermeier (Hab) 15:00 - 19:30: SEMINAR) Pre-University Science Education

Monday, September 11

09:00 -10:00: L01) Magnetic Nanostructures in the Lateral and Perpendicular Direction

Hartmut Zabel (Zbl) 10:00 -11:00: L02) Semiconductor Nanoparticles-Based

Gas Sensors For Cost-Effective Air Quality Monitoring Micro-Stations

Marie-Isabelle Baraton (Bar) 11:30 - 12:30: L03) Engineering of Mltifunctional

Nanoparticles for Biomedical Applications

Mamoun Muhammed (Muh) 12:30 - 13:30: L04) Effect of the Shell on the Blinking

Statistics of Single Core-Shell Quantum Dots

Colin D. Heyes (Hey)



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15:00 - 17:00: Paper Session A + B

17:30 - 19:30: Paper Session C + D

Tuesday, September 12 09:00 -10:00: L05) On the Design of Ordered Metal

Oxide Nanoarrays from Aqueous Solutions

Lionel Vayssieres (Vay) 10:00 -11:00: L06) Optical and Electronic Properties of

Small Size Silicon and Silicon-based Nanostructures

Aristides D. Zdetsis (Zdt)

Wednesday, September 13 09:00 -10:00: L07) Self-Assembled Nanostructured

Oxides Abdelkrim Chemseddine (Chn)

10:00 -11:00: L08) Synthesizing of Nanomaterials and

Nanocompositrs Powder by Mechanically-Induced-Solid-State Reaction and Subsequent Consolidation

M. Sherif El-Eskandarany (Esk)



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11:30 -12:30: L09) Oxide Interfaces – Is There Novel Materials Physics Emerging ?

Hanns-Ulrich Habermeier (Hab)

12:30 - 13:30: L10) Ultrafast Optical Response of Semicondcutor Nanocrystals

Mona Bakr Mohamed (Mon)

15:00 - 17:00: Paper Session E + F

17:30 - 19:30: Paper Session G + H

Thursday, September 14 09:00 -10:00: L11) Magnetic Properties of Spintronic

Materials Hartmut Zabel (Zbl)

10:00 -11:00: L12) Protein Folding Studied by Single

Molecule Fluorescence Resonance Energy Transfer

Colin D. Heyes (Hey)

11:30 -12:30: L13) On the Aqueous Thermodynamic

Stability of Metal Oxide Nanoparticles

Lionel Vayssieres (Vay)

12:30 - 13:30: Closing Ceremony



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Plenary Lecture Education and Economy -

An Analysis of Statistical Data

Hanns-Ulrich Habermeier

Max-Planck-Institut, Stuttgart, Germany E-mail: [email protected]

The correlation between education, basic research and economical strength at a national level has been frequently claimed and suggestive arguments for its existence have been given previously [1,2]. In this contribution an independent, more quantitative approach is attempted. The statistical data published by the OECD as well as the UNDP Human Development Reports are taken as source material and correlations between economical strength, the technology achievement and education indicators are developed. In the course of this analysis the concept of complex indicators is used rather than that of simple criteria. The analysis is given for the categories leading countries, potential leaders, dynamical adopters and developing countries. Based on the analysis caveats and recommendations for education issues will be developed with a focus on materials science.

[1] in “Condensed Matter and Materials Physics” National Research Council USA, National Academy Press, Washington D.C. USA 1999

[2] H.-U. Habermeier, J. of Education 24 ( 2002 ) 87



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L01

Magnetic Nanostructures in the Lateral and Perpendicular Direction

Hartmut Zabel

Department of Physics, Ruhr-Universität Bochum,

D-44780 Bochum, Germany www.ep4.rub.de; e-mail: [email protected]

Artificial magnetic nanostructures in the lateral and in the

perpendicular direction are being intensively studied because of their intriguing magnetic properties and their prospected use in spintronic devices. Perpendicular stacked magnetic heterostructures allow the investigation of collinear and non-collinear exchange coupling between ferromagnetic layers [1], exchange bias between ferro- and antiferromagnetic layers [2], confinement and scaling effects of spin density wave magnetism [3], and proximity effects between ferromagnetic and superconducting layers [4]. In the lateral direction a plethora of different shapes for ferromagnetic nanostructures can be realized such as stripes, dots, anitdots, rings, squares, rectangles, triangles, and different ellipsoids. These shapes usually require top-down lithographic processes [5]. Adding bottom up processes, additional degrees of freedom for lateral arrangements and self assembly of magnetic nanostructures are conceivable. The main interest in these nanostructures is the understanding of the domain structure in the ground state, the reversal mechanism in the space and time domain, and the dipole interaction between the elements. In this talk an overview will be presented on investigations of magnetic superlattices and lateral magnetic nanostructures using three main experimental techniques: vector and Bragg-MOKE [6], polarized neutron reflectivity [7], and resonant soft x-ray magnetic scattering [8]. This work is supported by SFB 491 and by BMBF 03ZA6BC2 and 05KS4PCA



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References are to work from the Bochum group: [1] A. Schreyer, J.F.Ankner, Th. Zeidler, H. Zabel, M. Schäfer,

J.A. Wolf, P. Grünberg, and C.F. Majkrzak, Phys. Rev. B 52, 16 066 (1995)

[2] F. Radu, M. Etzkorn, R. Siebrecht, T. Schmitte, K. Westerholt, and H. Zabel Phys. Rev. B 67, 134409 (2003); F. Radu, A. Westphalen, K. Theis-Bröhl and H. Zabel, J. of Physics: Condens. Matter 18, L29 (2006)

[3] E. Kravtsov, A. Nefedov, F. Radu, A. Remhof, H. Zabel, R. Brucas, B. Hjörvarsson, A. Hoser, G.J. McIntyre, J. of Phyiscs: Condensed Matter 17, 3143 (2005).

[4] L. Lazar, K. Westerholt, H. Zabel, L.R. Tagirov, Yu.. V. Goryunov, N.N. Garif'yanov, and I.A. Garifullin, Phys. Rev. B 61, 3711 (2000);

[5] A. Remhof, C. Bircan, A. Westphalen, J. Grabis, A. Nefedov, H. Zabel, Superlattice and Microstructures 37, 353 (2005).

[6] A. Westphalen, T. Schmitte, K. Westerholt, and H. Zabel, J. Appl. Phys. 97, 073909 (2005); A. Westphalen, K. Theis-Bröhl, H. Zabel, K. Rott, H. Brückl, J. Magn. Magn. Mater. 302 , 181–189 (2006)

[7] H. Zabel and K. Theis-Bröhl, J. Phys.: Condens. Matter 15, S505 (2003); K. Theis-Bröhl et. Al. Phys. Rev. B 71 020403 (2005).

A. Nefedov, J. Grabis and H. Zabel, Physica B 357, 22 (2005)



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L02

Semiconductor Nanoparticles-Based Gas Sensors For Cost-Effective

Air Quality Monitoring Micro-Stations

Marie-Isabelle Baraton

SPCTS – UMR CNRS 6638, Faculty of Sciences, 87060 Limoges, France

E-mail: [email protected]

Air pollution has been one of Europe’s main political concerns since the late 1970s. European Union policy on air quality aims to develop and implement appropriate instruments to improve air quality. As a result, the Member States have been instructed to establish a network of air quality monitoring (AQM) stations in their main cities and to inform citizens about the air quality on a daily basis. In the current AQM stations, the analyzers allow precise concentration measurements of different kinds of gaseous pollutants in air. But, they are expensive, complex and bulky equipment which do not allow “real time” dissemination of the information to the public because of the lengthy air sampling and data processing.

The objective of our two European projects was to provide an alternative approach consisting in the development of cost-effective mobile micro-stations based on semiconductor sensors. Indeed, by strongly reducing the cost of the stations, it will become possible to implement dense networks in every large city in every country. Improvement of the sensor sensitivity to detect very low levels of pollutants (CO, NO, NO2, O3) in air was the major challenge to take up. This was achieved by using metal oxide nanosized particles with both controlled size and surface chemistry, and by adapting the screen-printing process to the nanometer size specificity. The resulting sensors can be operated at lower temperature, thus reducing of the device power consumption. The detection thresholds for NO2, NO and O3 of our



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nanoparticles-based sensors have been decreased by a factor of 3 to 5 compared to currently commercialized chemical sensors.

Moreover, due to the tiny size of semiconductor sensors, it can then be envisaged to integrate different sensors in small sensing units, thus transforming the bulky expensive AQM stations into cost-effective portable devices. In a second step, these portable gas sensing units will communicate with a central computer via a wireless network based on the GSM protocol. Additionally, these sensing units can be associated to a global positioning system (GPS). The resulting communicating microstations, installed on mobile carriers such as city buses, will constitute a network of mobile AQM micro-stations, allowing rapid and versatile air quality monitoring in every city in every country at low cost.



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L03

Engineering of Mltifunctional Nanoparticles for Biomedical

Applications Mamoun Muhammed

Material Chemistry Division Royal Institute of Technology,

100 44 Stockholm, Sweden [email protected]

Nanotechnology has placed a great emphasis on the development of “bottom-up” strategies for the self-assembly of (macro) molecular and nanoparticles as building blocks to construct larger functional devices. Novel and innovative approaches have been developed for the fabrication of advanced nanoparticles; e.g. core-shell structures, suited for a wide range of industrial and technological applications.

Recently, there has been great interest in developing advanced uses of functional nanoparticles for biological and medical applications. Smart and multifunctional nanoparticles are envisaged to be of great importance in several biotechnology and medical applications including controlled drug delivery, tissue engineering, bio-diagnostics and MRI, etc. Bio-compatible and bio-active superparamagnetic iron oxide nanoparticles (SPION) are prime candidates as magnetic carriers and for labeling cells or organs which can be monitored by magnetic resonance imaging (MRI). Novel materials such as PtFe are being developed.



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A novel way for controlled drug-supply can be achieved through the use of environment sensitive nanoparticles. In this way, biocompatible particles-containing therapeutics can be used to target specific tissues or organs. The particles can be driven to and/or maintained at the required location using suitable targeting mechanisms (chemical, magnetic, etc.). The release of the drug can be triggered by chemical (concentration) or physical (temperature) conditions where the delivery rate determined by a combination of chemical dissolution and diffusion processes can be controlled. The surfaces of the nanoparticles can be engineered (e.g. through additional surface layer) to exert a higher degree of control on the rate of therapeutic release.

In this talk, a presentation of some recent research on the design and fabrication of multifunctional nanoparticles together with example of biomedical applications for drug delivery, bio-diagnostics and MRI.



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L04

Effect of the Shell on the Blinking Statistics of Single Core-Shell Quantum

Dots

Colin D. Heyes1, Andrei Yu. Kobitski1, Vladimir V. Breus1 and G. Ulrich Nienhaus1,2

1Department of Biophysics, University of Ulm, Albert Einstein Allee 11,

89069 Ulm, Germany 2Department of Physics, University of Illinois at Urbana-Champaign,

Urbana, IL 61801,USA

Fluorescence blinking of single quantum dots (QDs) under constant illumination has attracted a great deal of attention from both experimentalists and theoreticians. To explain the power-law behavior in the distribution of both “on” and “off” times, several models have been proposed, in which the charge carrier is either ejected from the QD to an external trap or is localized at a trapping site within the QD. To gain insight into the blinking mechanism, we have studied the role of the shell of CdSe-ZnS core-shell QDs. For two sets of samples varying in the fluorescence quantum yield of the core, we systematically varied the thickness of the shell and analyzed the blinking behavior of a statistically significant number of single QDs. In both cases, the distributions of “on” and “off” times were independent of the ZnS shell thickness. These data can be explained with a recently introduced model [Frantsuzov and Marcus, Phys. Rev. B 72, 1553211 (2005)]. After photo-induced creation of an electron-hole pair, the hole is trapped in a deep surface state of the CdSe core, and the excess energy is transferred to the electron in an Auger process, raising it from the 1Se to the 1Pe state. The energy gap between these electronic states is assumed to perform stochastic diffusion so that it can be either in resonance or out of resonance with the energy gap between the hole states. The dynamics results in the power law



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behavior of the “on” and “off” times distribution, the exponential cutoff of the power law dependence at long “on” times and the lacking dependence of the blinking kinetics on the shell thickness. This model also explains our observation that the overall quantum yield of an ensemble is mainly governed by the fraction of non-emitting particles in the sample.



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L05

On the Design of Ordered Metal Oxide Nanoarrays from Aqueous Solutions

Lionel Vayssieres

National Institute for Materials Science,

International Center for Young Scientists, Japan The ability to design one-dimensional building blocks with

tailored aspect ratio and to order them into large 3-D arrays is an important challenge scientists have to face to create smart and functionalized nanodevices. Our approach to control the size and shape of nanoparticles as well as the overall texture of particulate thin films is to tune their direct aqueous hydrolysis-condensation growth onto substrates by monitoring the interfacial thermodynamics of nanocrystals as well as their kinetics of heteronucleation. This is achieved by minimizing the surface energy at the water/oxide interface according to a general quantitative model based on Gibbs adsorption equation. Indeed, growing materials at very low interfacial tension, i.e. at thermodynamically stable conditions, allows the experimental control of the extension and rate of the nucleation and growth stages. Thus, different sizes, shapes, and orientations can be generated onto various substrates. Consequently, the design and fabrication of novel devices with tailored and engineered three-dimensional architecture can be obtained from aqueous solution without template, surfactant, applied field, or undercoating. Such ideas will be demonstrated on transition metal oxides materials at nano-, meso-, and micro-scale, and illustrated on their growth as 3-D arrays with controlled orientations onto various substrates as well as the characterization of their electronic structure, photoelectrochemical, and magnetic properties.



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L06

Optical and Electronic Properties of Small Size Silicon and

Silicon-based Nanostructures Aristides D. Zdetsis

Department of Physics, university of Patras, 26500 Patras, Greece, [email protected]

URL: http://moleng.physics.upatras.gr/personnel/ADZdetsis.html

The Optical and electronic properties of small size Si, Ge and SiGe nanocrystals (up to 25 Å in diameter) and nanowires (up to 75 Å in length) are examined and critically reviewed within the framework of high level and high accuracy ab initio calculations based on “static” and time-dependent density functional theory. These calculations [1-4] are supported by sophisticated quadratic configuration interaction and other multi-reference methods, such as multi-reference second order perturbation theory (for the smaller systems). We examine, among others, the origin of the gap, the role of surface oxygen or hydrogen, the role of germanium substitution and the critical dimensions for visible photoluminescence. The agreement of our theoretical predictions for the silicon nanocrystals with accurate experimental results is excellent, despite other conflicting experimental and theoretical results. The main sources of conflict in the experimental results are oxygen contamination, preparation conditions and difficulties in size determination. The theoretical controversies are due to either poor treatment of correlation and exchange, or incorrect fitting of empirical parameters.



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L07

Self-Assembled Nanostructured Oxides

Abdelkrim Chemseddine

Hahn-Meitner-Institut, Berlin, Germany

In current research on nanocrystals and nanostructured materials, structural control at all hierarchies of organization ranging from material texture to the level of atomic structure is a major challenging goal. One promising strategy for the processing of such materials involves clusters or nanocrystals which have the propensity to self-assemble into desired structures. The generation of such precursors with well defined size, shape and surface structure requires the investigation of chemical reactivity, nucleation, growth, growth termination and surface functionalization.

This lecture will discusse the issues in this strategy toward Self-assembled nanostructured oxides and will be illustrated in the case of titanium dioxide which has been particularly successful. A variety of techniques such as optical absorption, fluorescence, Raman and infra-red spectroscopies, X-rays diffraction, HRTEM,, STM and SEM were used in these investigations and in the structural characterization of different self-assembled nanocrystals. The size-dependent physical properties which offer a great advantage in finding the right physico-chemical conditions to generate these clusters, nanocrystals and assemblies will be adressed.

The processing of highly nanostructured titania as self-cleanning coating for windows will demonstrate the importance of this strategy in making pores and cracks free films with a controlled thickness, high transpareny and high photocatalytic activity. Some progress im making other oxides will be presented.



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L08

Synthesizing of Nanomaterials and Nanocompositrs Powder by

Mechanically-Induced-Solid-State Reaction and Subsequent Consolidation

M. Sherif El-Eskandarany

Technology Development & Scientific Services Sector Academy of Scientific Research & Technology

101 Kasr Al-Aini Street, Cairo 11516, Egypt

Most crystalline solids are composed of a collection of many small crystals or grains; termed polycrystalline. The term nanomaterials (also known as nanocrystalline materials)is used to describe those materials that have a majority of grain diameters with sizes less than 100 nm. Whether it can be called a revolution or simply evolution, the nanomaterials have received much attention as advanced engineering materials with unique physical and mechanical properties. A wide variety of techniques are being used to synthesize these materials including inert gas condensation, rapid solidification, electrodeposition, sputtering and chemical processing. The mechanically-induced-solid-state reaction (MISSR), which induces heavy cyclic deformation in powders, has been considered as an attractive and promising technique for preparing large amount of nanomaterials. Unlike many of the traditional way of fabrication, MISSR using ball milling technique produces its nanostructures not by clustering assembly but by grain refining as the result of sever plastic deformation.

This review article will present the most recent results of my team work (in both Egypt and Japan) in this hot area, taking the synthesizing of refractory materials (e.g. TiC, ZrC, WC, TiN, ZrN)



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and nanocomposites (e.g. Al-SiC, Al-Si4N3, WC-MgO, WC-Al2O3) as typical examples. The consolidation techniques that are used to obtain bulk nanomaterials and some physical and mechanical properties of these materials will be presented.



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L09

Oxide Interfaces – Is There Novel Materials Physics Emerging ?

Hanns-Ulrich Habermeier

Max-Planck-Institut, Stuttgart, Germany E-mail: [email protected]

Reducing the dimensions of a solid state material below 100nm causes a size dependent change of its properties including size-dependent quantum effects. This well known aspect of physics at the nanoscale is at the core of current nanoscience research. In contrast to the mainstream research in nanoscience this review covers novel apsects of interface physics using the interface of oxides with different functionality. Physics phenomena at the interface have gained tremendous attention in the field of semiconductor science where properties of the 2- dimensional and 1- dimensional electron gas yielded a new deep insight into fundamental properties of matter such as the Quantum Hall Effect and Fractional Quantum Hall Effect. As an emerging topic oxide electronics gains increasing attention, the current understanding of oxide interfaces, however, is rather rudimentary.

Starting from empirical findings in ferromagnet – superconductor oxide thin film heterostructures and superlattices such as the systematic change of the ordering temperatures with the superlattice composition, spin polarized qusiparticle self-injection and magnetic interactions, an analysis of recent experiments is given taking into account charging effects of interfaces as well as orbital interactions across interfaces. In the talk some technological requirements are highlighted, the emphasis, however, is laid on the novel physics approach to treat these interfaces.



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L10

Ultrafast Optical Response of Semicondcutor Nanocrystals

Mona Bakr Mohamed

National Institute of laser Enhanced Sciences (NILES),

Cairo University, Egypt

The ultrafast carrier dynamics of semiconductor nanocrystals can be monitored using femtosecond laser spectroscopic techniques such as time resolved femtosecond pump-probe and femtosecond up-conversion fluorescence spectroscopy. The use of these techniques in determining the fine electronic structure and the lifetime of the electron and hole will be explained in details. This talk will cover the effect of size and shape of the semiconductor nanocrystals on their relaxation dynamics. In addition, the multiexcitons formation and their decay kinetics will be discussed, since more than one exciton can be generated per particle under high excitation power. Understanding the effect of laser power on the spectroscopy and relaxation dynamics of semiconductor nanoparticles is essential especially for the use of these materials in optoelectronic devices, which perform under high excitation power such as laser or light emitting diode.



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L11

Magnetic Properties of Spintronic Materials

Hartmut Zabel*

Department of Physics, Ruhr-Universität Bochum,

D-44780 Bochum, Germany www.ep4.rub.de; e-mail: [email protected]

Dilute magnetic semiconductors (DMS), in which a small fraction of non-magnetic host semiconductor atoms is replaced by magnetic ions, are key spintronic materials intended to manipulate both, the spin and the charge degrees of freedom of carriers in semiconductor devices [1]. Doping of III-V compound semiconductors with magnetic ions leads to a ferromagnetic state at low temperatures. Although highly interesting from a fundamental point of view, more important from an applied viewpoint are materials which either have a high Curie temperature above room temperature and/or a high spin polarization at the Fermi level. Recently several oxide-based DMS have been reported to be promising candidates for room temperature ferromagnets. In particular, Co-doped TiO2 has been reported to be a robust ferromagnet with a Curie temperature as high as 650 K [2]. Nevertheless, the present experimental situation is rather unclear. Several investigations explained that cobalt ions in TiO2 exist in a +2 oxidation state, consistent with ferromagnetism that originates from Co substitution on Ti sites [3], while other publications suggest the precipitation of cobalt metal atoms into clusters [4]. Recently, we have reported room temperature ferromagnetism and in-plane magnetic anisotropy of single-crystalline rutile structures after Co ion-beam implantation [5, 6]. From the observation of in-plane magnetic anisotropy we concluded that ferromagnetism in this system results from incorporation of Co ions in the TiO2 lattice. Furthermore, with x-ray



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circular magnetic dichroism and resonant magnetic x-ray scattering we could confirm not only the magnetic state of Co2+ but also the polarization of oxygen in close proximity with the Co ion. In this presentation, a brief overview will be provided on the present state of oxide based dilute magnetic semiconductors. [1] S. A. Wolf, D.D. Awschalom, R.A. Buhrman, J.M. Daughton,

S. von Molnar, M.L. Roukes, A.Y. Chtchelkanova and D.M. Treger, Science 294, 1488 (2001)

[2] Y. Matsumoto, M. Murakami, T. Shono, T. Hasegawa, T. Fukumura, M. Kawasaki, P. Ahmet, T. Chikyow, S.-Y. Koshihara, and H. Koinuma, Science 291, 854 (2001).

[3] D. H. Kim, J. S. Yang, K. W. Lee, S. D. Bu, T. W. Noha, S-J. Oh, Y-W. Kim, J-S. Chung, H. Tanaka, H. Y. Lee and T. Kawai, Appl. Phys. Lett. 81, 2421 (2002).

[4] S. A. Chambers, C. M. Wang, S. Thevuthasan, T. Droubay, D. E. McCready, A. S. Lea, V. Shutthanandan, and C. F.Windisch Jr., Thin Solid Films 418(2), 197 (2002).

[5] N. Akdogan, B. Z. Rameev, L. Dorosinsky, H. Sozeri, R. I. Khaibullin, B. Aktaş, L. R. Tagirov, A. Westphalen and H. Zabel, J. Phys.: Condens. Matter. 17, L359 (2005).

[6] N. Akdogan, A. Nefedov, A. Westphalen, H. Zabel, R.I. Khaibullin and L.R. Tagirov, J. Magn. Magn. Mater. 300, e4-e7 (2006).

* Work performed together with: N. Akdogan, B. Aktas, R.I.

Khaibullin, A. Nefedov, B.Z. Rameev, L.R. Tagirov, A. Westphalen. This work was partially supported by DFG through SFB 491.



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L12

Protein Folding Studied by Single Molecule Fluorescence Resonance

Energy Transfer

Colin D. Heyes1, Elza Kuzmenkina1 and G. Ulrich Nienhaus1,2

1Department of Biophysics, University of Ulm, Albert Einstein Allee 11,

89081 Ulm, Germany 2Department of Physics, University of Illinois Urbana-Champaign,

Urbana, IL 61801, USA

Proteins are highly complex nanosystems consisting of multiple conformations and heterogeneous dynamics. The question of how an unfolded protein folds to a specific structure from the astronomical number of possibilities on relatively short timescales has intrigued scientists since Anfinsen showed that all the information necessary to find this structure is encoded in the 1-dimensional amino acid sequence. The protein-folding problem has seen a resurgence in recent years due to the connection of several diseases with incorrect protein folding. We use the technique of single molecule Förster (or fluorescence) resonance energy transfer (FRET) on immobilized RNase H protein molecules to follow the structure and dynamics of proteins under destabilizing conditions. We observe transitions between discrete unfolded conformations occurring on the second timescale even under harsh destabilizing conditions. From these kinetics we are able to calculate the energy barriers between the different conformations. We also find that the average size of the unfolded protein increases with denaturant concentration, which we have quantitatively analyzed using a model of a continuum of unfolded substates along a reaction coordinate described by the



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cooperativity of the substates. From this data we extract various thermodynamic parameters, which are used to present a quantitative folding landscape of RNase H.

References 1. Elza V. Kuzmenkina, Colin D. Heyes and G. Ulrich Nienhaus.

Single Molecule FRET Study of Denaturant Induced Unfolding of RNase H. (2006). J. Mol. Biol., 357, 313-324.

2. Elza V. Kuzmenkina, Colin D. Heyes and G. Ulrich Nienhaus. Single Molecule FRET study of Protein Dynamics under Denaturing Conditions. (2005). Proc. Natl. Acad. Sci., 102, 15471-15476.

3. Elza Amirgoulova, Jürgen Groll, Colin D. Heyes, Thomas Ameringer, Carlheinz Röcker, Martin Möller and G. Ulrich Nienhaus. Biofunctionalized Polymer Surfaces Exhibiting Minimal Interaction Towards Immobilized Proteins. (2004). ChemPhysChem., 5, 552-555.

4. Jürgen Groll, Elza Amirgoulova, Thomas Ameringer, Colin D. Heyes, Carlheinz Röcker, Martin Möller and G. Ulrich Nienhaus. Biocompatible Ultrathin Coatings of Cross-linked Star-shaped Poly(ethylene oxide) allow reversible folding of single immobilized RNase H molecules. (2004). J. Am. Chem. Soc., 126, 4234-4239

5. Colin D. Heyes, Andrei Yu. Kobitski, Elza V. Amirogoulova and G. Ulrich Nienhaus. Biocompatible Surfaces for Specific Tethering of Single Protein Molecules. (2004). J. Phys. Chem. B., 108, 13387-13394.



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L13

On the Aqueous Thermodynamic Stability of Metal Oxide Nanoparticles

Lionel Vayssieres

National Institute for Materials Science,

International Center for Young Scientists, Japan Divided and ultra-divided systems such as colloidal and nanoparticle dispersions are generally unstable with regard to the size and number of their constituents because the solid-solution interfacial tension, acting as a driving force, leads to a reduction of the surface area to minimize the dispersion free enthalpy. Such phenomenon known as surface energy minimization induces an increase in average particle size as a result of the decrease of the surface area at constant volume. For such a reason such dispersions are usually considered thermodynamically unstable. However, they can be thermodynamically stabilized if, by adsorption, the interfacial tension of the system becomes very low. This phenomenon, well known for microemulsions, is for the first time quantitatively modelled and demonstrated for transition metal oxide nanoparticles. When the pH of precipitation is sufficiently far from the point of zero charge and the ionic strength sufficiently high, the ripening of nanoparticles is avoided and their size can be monitored over one order of magnitude by tailoring solution pH and ionic strength. A model based on Gibbs adsorption equation leads to an analytical expression of the water-oxide interfacial tension as a function of the pH and the ionic strength of the dispersion/precipitation medium. The stability condition, defined by a “zero” interfacial tension, corresponds to the chemical and electrostatic saturation of the water-oxide interface. In such a condition, the density of charged surface groups reaches its maximum, the interfacial tension its minimum and further adsorption forces the surface area to expand and consequently,



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the size of nanoparticles to decrease. An excellent agreement was found between the model prediction and the experimental results obtained from the aqueous precipitation of magnetite (Fe3O4) nanoparticles in basic medium. A general control of the metal oxide nanoparticle size when precipitated far from their point-of-zero-charge is thus expected.



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Session A

Monday, Sept., 11, 2006 15:00 – 17:00

Chairman

Prof. M. S. El-Eskandarany Prof. M. El-Zawawy



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A1 A Few Structural Regularities of Carbon Nanotubes

A. A. Mansurov, T. A. Shabanova, Maroof Higazi, R. M. Mansurova

Al-Farabi Kazakh National University, Combustion Problem Institute,

172 Bogenbay Batyr St., Almaty 050012. Kazakhstan e-mail: [email protected], Fax: +8-(3272)-925-811

Graphite nanotubes and fullerene structures are usual objects of research. However, some tubefibrous structures are occurred more often in synthesized and natural samples. We have shown that graphite crystallite-regardless of particle size-has electronogram reflexes typical for graphite structure. Films roll up and split corresponding reflexes of crystal plane. Some particles having structure similar to graphite show the characteristic pictures of microdiffraction electrons too. Mostly the electronograms of usual nanotubes do not show such features. We detected and described an especial tubular structure among native carbon samples of nanotubes. Its analog was not observed as yet in our artificially made carbon substances. It seems it was a huge tubulens. It is thought that roentgen amorphous substance have absence of structural regularities or big dispersity of crystals. There is probably one more reason. That is molecular crystals with fullerence similar groups in lattice points such as in revealed tubulens and fullerenes particles.



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A2 Optical Transitions in Semiconductor Cylindrical Nanolayer in the Presence of Radial Electric Field

V.A.Harutyunyan*, S.L. Harutyunyan, G.H.Demirjian

State Engineering University of Armenia, Gyumri Branch,

Gyumri State Pedagogical Institute

Along with many low-dimensional systems different axial-symmetrical semiconductor nanocrystalline layers have been studied intensively both experimentally and theoretically during the last decade. These heterophase systems combine a number of physical characteristics of both quantized films and quantum wires and therefore they are very perspective in terms of creation of up-to-date optoelectronic devices. Thereupon, it is interesting to investigate the modulating influence of different external static fields on the physical characteristics of such semiconductor layers. In this report the influence of lateral (radial) electrostatic field on the electronic and optical properties of semiconductor cylindrical heterolayer is investigated theoretically. The following problems are considered:

a) Modification of energy spectrum of charge carriers in the layer under radial electric field, and

b) The influence of this field on the layer’s optical absorption spectrum.

The structure under consideration is presented as a heterocomposition core/layer/medium (specifically the real CdS/HgS/CdS composition is discussed). In this composition the charged core plays the role of the “source” of radial electric field. The energy spectrum and envelope wave functions of charge carriers in the layer under radial field are obtained. In dipole approximation, the optical absorption coefficient for direct optical transitions in the layer is calculated in the presence of radial electric field.

* E-mail: [email protected]



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The comparative analysis shows that the radial field effectively widens the band gap of the layer. This widening is defined by the intensity of external field and by the geometrical sizes of the sample. At the same time the external field “cancels” any selection rules by radial quantum number. As a result new “satellite” lines appear in the optical absorption spectrum of the layer. The threshold frequencies and corresponding intensities of these new lines are defined by Stark shifts’ values of charge carriers’ energies. The radial field also leads to an explicit dependence of absorption from the effective masses of charge carriers.



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A3 Magnetic Structure of Manganese Ferrite

Nano-Particles

Talaat. M. Meaz.*, M. A. Amer1and M. K. El-Nimr.

1Physics Department, Faculty of Science, Tanta University, 31527 Tanta, Egypt.

E-mail:[email protected]

Mnx Fe2-x O3 Ferrite particles with x = 0.067- 0.467 and with particle diameters in the range 7.5 – 17 nm have been synthesis (by co-precipitation technique) and studied by x-ray and Mössbauer spectroscopy. At room temperature the spectra are affected by superparamagnetic relaxation and the relaxation time decreases with decreasing the particle sizes and increasing manganese content. At low temperature all the spectra are magnetically split and show asymmetry of the line intensities similar to that of pure γ-Fe2O3. Measurements at 5 K in large applied magnetic fields parallel to the gamma ray direction showed that lines 2 and 5 did not vanish completely. This indicates the presence of spin-canting effects. The results are in accordance with the presence of a ferromagnetic core with a 0.3- 0.7 nm thick canted surface layer. There is no indication of any influence of the amount of manganese on the spin canting.



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A4 Magnetic Properties of CoFe2-xSmxO4 Nanoparticles

Synthesized by Citrate Precursor Method

M. M. Rashad1*, R. M. Mohamed1 and H. El-Shall2

1Central Metallurgical Research and Development Institute,

P.O. Box: 87 Helwan, Cairo, Egypt, Fax:202-5010639 2Particle Engineering Research Center, Materials Science and

Engineering Department, University of Florida, FL, USA E-mail: [email protected]

CoFe2-XSmXO4 (where X = 0 to 0.4) nano-crystalline powders have been

prepared by a citrate precursor method. The effect of substitution Fe3+ ions by Sm3+ ions and thermally treated temperature (400-1000 oC) on the structure, crystallite size and magnetic properties of the produced cobalt ferrites nanocrystals were investigated. The produced materials were characterized by X-ray diffraction analysis (XRD) and the results reveal that a single phase of cobalt ferrite was formed without Sm addition at different thermal treated temperature. Addition of Sm was shifted the main strongest peaks of cobalt ferrite at low temperature and it led to the formation of new phases at high temperature. The average crystallite sizes of the materials were varied by altering the synthetic conditions and were within the average range of 9 nm and a maximum 86 nm. The magnetic properties of the produced powders have been studied by using vibrating sample magnetometer (VSM). Saturation magnetization and coercive field are strongly dependent on the calcination temperature and Sm content. The saturation magnetization is decreased by increased the Sm content and increased by increased the calcination temperature from 400-800 oC



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A5 Application of Statistical Design to Optimize the Synthesis of Barium Titanate Nanopowders by

Hydrothermal method

M.M. Rashad1, R.S. Mohmmed1, A.El. Midany1and A.K. Kandil 2, I.A. Ibrahim1

1 Central Metallurgical Research and Development Institute, P.O.Box:87 Helwan, Cairo, Egypt 11421

2 Inorganic and Nuclear Chemistry Department, Faculty of Science, Helwan University, Cairo, Egypt

Barium titanate BaTiO3 (BT) nanopowders from aqueous solution have been prepared based on hydrothermal method. Statistical design was used to investigate the effect of main parameters, i.e. pH (12-14), hydrothermal time (12-24 hrs) and hydrothermal temperature (150-2000C) on the formation of barium titanate phase. BaTiO3 particles were investigated using XRD, SEM and laser diffraction analyzer analysis. From XRD data, the results showed that pure single phase barium titanate was significant with pH, hydrothermal time and hydrothermal temperature and the formation increased by increased the pH up to 13. The average crystallite sizes of the produced BT nanopowders were in the range from 60 nm to 80 nm. SEM micrographs showed that the morphology of the produced single phase barium titanate particles was tetragonal phase at low temperature and hydrothermal time and it transformed to cubic phase by increased the hydrothermal temperature and time. Laser diffraction analyzer data of the produced barium titanate powders showed that the mean particle sizes were from3 to 5 µm.



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A6 Micro and Nano Characterization of Thin Film

with N ions implanted in surface

B. Škorića*, G. Favarob, D. Kakaša, and A. Miletić a

aUniversity of Novi Sad, Faculty for Technical Sciences 21000 Novi Sad, Trg D.Obradovića 6., Serbia and Montenegro

bCSM Instruments SA, Peseux, Switzerland [email protected]

In the present investigation the duplex coated and surface modified with

ion implantation was studied Thin films are playing important role for industrial applications. A duplex surface treatment involves the sequential application of two surface technologies to produce a surface composition with combined properties. A typical duplex process involves plasma nitriding and the coating treatment of steels. In this paper subsequent ion implantation was provided with N5+ ions. The plasma ion implantation was applied to enhace the mechanical properties of surface. The three basic points that are considered fundamental to studies of friction are the surface area and nature of the intimate asperity contacts, the surface adhesion and shear strength, and the nature of deformation and energy dissipation occurring at the asperity junctions The most successful and widespread model for nanoindentation data analysis is one in which the unloading data are assumed to arise from a purely elastic contact. The form most often used is known as the Oliver and Pharr method. In this paper Indentation was performed with CSM Nanohardness Tester. The results are analyzed in terms of load-displacement curves, hardness, Young's modulus, unloading stiffness and elastic recovery. The nanohardness of coating measured by Berkovich indenter is about 42.4 GPa. The film deposition process exerts a number of effects such as crystallographic orientation, morphology, topography, densification of the films.The evolution of the microstructure from porous and columnar grains to densel packed grains is accompanied by changes in mechanical and physical properties. A variety of analytic techniques were used for characterization, such as scratch test, calo test, SEM, AFM, XRD, GIXRD and EDAX. Therefore, by properly selecting the processing parameters, well-adherent TiN films with high hardness can be obtained on engineering steel substrates.



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A7 Structural Study of the Mechanically Alloyed

Fe-Mo Nanopowders

H. Moumeni (1,2,*), A.R. Nemamcha (1), S. Alleg (2), and J. M. Grenèche (3)

(1) Faculté des Sciences et de l’Ingénierie, Université 08 Mai 1945,

Guelma, B.P.401, Guelma 24000, Algérie (2) Laboratoire de Magnétisme et de Spectroscopie des Solides LM2S,

Université Badji Mokhtar, Annaba, B.P.12, Annaba 23000, Algérie. (3) Laboratoire de Physique de l’Etat Condensé, UMR CNRS 6087,

Université du Maine, F-72085, Le Mans Cedex 9, France. *) [email protected]

Fe-Mo nanostructured compound is prepared by high energy ball milling in a P7 planetary ball mill under argon atmosphere with a ball to powder weight ratio of about 20:1. The structural evolution during mechanical alloying was examined by X-ray diffraction analysis. Mössbauer spectrometry was used to determine the local iron environment changes as a function of milling time. The X-ray diffraction analysis shows that the total amount of molybdenum is not completely dissolved into the Fe matrix. The X-ray diffraction pattern of the powder milled for 24 h shows the formation of a bcc FeMo solid solution and molybdenum nanocrystals. The Mössbauer spectrum of the 1 h milled sample showed the typical sextet corresponding to α-Fe. With increasing milling time, the presence of Mo in the vicinity of Fe is clearly evidenced by the appearance of more and less resolved satellites on the Mössbauer spectra. The fitting results of the Mössbauer spectra obtained at 300K in standard transmission geometry, using a discrete hyperfine magnetic field distribution, revealed the coexistence of three environments types. Both average hyperfine magnetic field and isomer shift variations as a function of milling time will be reported.




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A8 Electric properties of Nickel-nanoparticle-

Containing Inhomogeneous Materials in the Vicinity of Percolation Threshold

U. Abdurakhmanov, Sh. Sharipov, F. Boymurotov., Y. Rakhimova

Physics Faculty, National University of Uzbekistan, Tashkent,

100174, Uzbekistan

In resent years, the interest in nanoparticle-containing materials is growing explosively owing to their unique physical properties, which are substantially different from properties of corresponding compact materials. Among these materials there are various composites containing of metal nanoparticles randomly distributed in a dielectric matrix. The application of the classical percolation theory for description of the electric properties of these composites faces problems (Balberg et al. Int. J. Mod. Phys. B, 18, 2091-121 (2004). In this report we present results of study of the behavior of the conductivity σ and static permittivity ε of composites containing the nickel nanoparticles (≤ 30 nm) embedded in a polymeric matrix and also in a ceramic one by comparing with the behavior of the same electric parameters of composites containing the high-dispersed (1-3 µm) nickel particles embedded in the same matrices. It is demonstrated that the form of dependences of σ and ε on the fractional Ni (V) content is depended on the sizes of the Ni particles for both polymer and ceramics-based composites. For these composites with the Ni nanoparticles, in the range below classical percolation threshold Vc, the dependences of σ and ε on V are different from that predicted by the classical percolation theory with the fact that the curve of this dependence for ε is similar to that for σ. Following Balberg et al, this peculiarity of the V-dependence of σ was assigned to the low percolation threshold Vcd. It is concluded that, in the nickel-nanoparticle-containing material under study, the percolation-tunnelling process, which is considered by Balberg et al. as the cause of the low percolation threshold Vcd also determines the behaviour of ε in the range below classical percolation threshold Vc.



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A9 Preparation and characterization of ZnSe

nanoparticles by mechanochemical process

M. Abdel Rafea

Mubarak City for Scientific Research & Technological Applications Institute of Advanced Technilogy and New Materials

Electronic materials Dep. E-mail: [email protected]

Nanocrystalline ZnSe powder was prepared by mechano chemical

process from Zn and Se pure granules. Zn and Se granules transformed to powder during mechano chemical reaction and ZnSe phase was observed after milling time of 16 min by XRD measurements. The crystallite size was measured to be 9-10 nm while the powder particle size was found to be in the range 90-500 nm in the milling time range 20-60 min as measured by size analyzer and SEM. The homogeneity of the powder was confirmed by EDX analysis. The optical band gap was estimated from optical absorbance curve and has the value in the range 2.58-2.95 eV. The absorbance peak was observed to be wider according the wide distribution of the crystallite size which affect on the energy gap according to energy gap confinement and the broadening of the absorption peak was due to several energy gaps according to several sizes of the crystallites



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A10 The Effects of Induction and Convention Aging on

Growth Kinetics and Distribution of Nano-Metric γ' Precipitates in a Ni-Based Superalloy

S. Soleimani, A. Abdollah-zadeh∗, A. Samadi, H. Assadi

Department of Materials Engineering, Tarbiat Modares University,

P. O. Box: 14115-143, Tehran, Iran

Ni-based superalloys are the most complex and the most widely used

materials for manufacturing of critical gas turbine components. It is well known that these materials own their high temperature strength from the fine particles of LI2 type ordered γ' phase precipitated coherently with the matrix. The mechanical properties of these alloys are dependent upon such factors as volume fraction, particle size, nucleation, growth and coarsening rates and composition of γ' phase. All of these factors are determined by the solution and aging treatments. In this work, the effect of induction aging on the microstructure and the hardness of a cast superalloy, Udimet500, is investigated. The solution samples were aged in two different furnaces namely induction furnace and resistance tube furnace at 850oC up to 2 hours. The age-hardening behavior and microstructural characteristics were studied by hardness testing, scanning electron microscopy (SEM), electron image analyzing, X-ray diffractometery, electrolytic extraction and light laser scattering (LLS). The results show that the rate of growth of γ' precipitates compared to resistance samples is considerably accelerated. This observation can be attributed to the increasing effect of induction aging on the growth of γ' precipitates due to an increase in the rate of diffusion of γ' constitutional elements.




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A11 Development of a New and Novel Molecular Building Block Methodology for Synthesis of

Naonostructured Mesoporous Catalysts

N. N. Ghosh*, and C. E. Barnes

*Department of Chemistry, Birla Institute of Technology and Science- Pilani, Goa campus, Zuarinagar, Goa 403726 India

Department of Chemistry, University of Tennessee- Knoxville, USA

The preparation of homogeneous dispersions of metal species on the

surfaces of porous, high surface area supports such as SiO2 or Al2O3 has been a goal of heterogeneous catalyst scientists for many years. Commonly used procedures involve the impregnation of the support with an aqueous solution of a catalyst precursor, hydrothermal, sol–gel technologies. Working in aqueous media, however, limits the number of synthetically accessible species and distributions of aggregated species often result. To overcome these limitations, we are developing a novel and versatile chemical route involving the controlled coupling of silicate based molecular building blocks to construct the support while simultaneously incorporating various metal ions onto the support surface to prepare nanostructured silica supported catalysts. Here we describe results from our investigations into the linking of the cubic Si8O20 spherosilicate unit with vanadyl chloride (VOCl3). We have been able to alter the connectivity of vanadium to the silicate support while maintaining monodispersed vanadium centers throughout the matrix. This molecular Building Block methodology has the potential to create materials containing tailored distributions of catalytically active metal centers in a robust, nonreactive cross-linked matrix of structural building blocks. The utilization of building blocks in this motif pushes structural properties such as the separation of catalytic sites and the pore diameter into the mesoporous regime.



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A12 Application of Statistical Design to Optimize the Synthesis of Barium Titanate Nanopowders by

Hydrothermal Method M.M. Rashad1, R.S. Mohmmed1, A.El. Midany1 A.K. Kandil 2, and I.A.

Ibrahim1

1 Central Metallurgical Research and Development Institute, P.O.Box:87 Helwan, Cairo, Egypt 11421

2 Inorganic and Nuclear Chemistry Department, Faculty of Science, Helwan University, Cairo, Egypt

Barium titanate BaTiO3 (BT) nanopowders from aqueous solution have been prepared based on hydrothermal method. Statistical design was used to investigate the effect of main parameters, i.e. pH (12-14), hydrothermal time (12-24 hrs) and hydrothermal temperature (150-2000C) on the formation of barium titanate phase. BaTiO3 particles were investigated using XRD, SEM and laser diffraction analyzer analysis. From XRD data, the results showed that pure single phase barium titanate was significant with pH, hydrothermal time and hydrothermal temperature and the formation increased by increased the pH up to 13. The average crystallite sizes of the produced BT nanopowders were in the range from 60 nm to 80 nm. SEM micrographs showed that the morphology of the produced single phase barium titanate particles was tetragonal phase at low temperature and hydrothermal time and it transformed to cubic phase by increased the hydrothermal temperature and time. Laser diffraction analyzer data of the produced barium titanate powders showed that the mean particle sizes were from3 to 5 µm.



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A13 Carbon Structures Formed in Different Chemical

Processes

Z.A.MANSUROV, T.A.SHABANOVA, MAROOF HIGAZI, N.N.MOFA, M.A.BIISENBAEV, R.M.MANSUROVA.

Al-Farabi Kazakh National University, Combustion Problem Institute,

172 Bogenbay Batyr St., Almaty 050012, Kazakhstan e-mail: [email protected], Fax: + 8-(3272)-925-811

We have analysed some nano dimensional carbon particles obtained in chemical processes on various initial matrixes. There are seven frequently occurring types of nano dimensional particles and structures: (1) spherical, (2) tubular, (3) fibrous, (4) filmy, (5) crystalline, (6) - “active", and (7) cloudy. We detail each kind of these objects. Process of carbonization forms practically all familiar structures of carbon nanoparticles with a prevalence of some of them. Round particles and various kinds of tubular particles are formed more often by pyrolysis of hydrocarbons on metals. Large graphite nanotubes and fullerenes are formed mostly in an electric arc. Mechano-chemical processes with modifiers containing carbon yield usually some film structures. The basic part of substance in our research has not had any structural orderliness of graphite. We assume that any types of above nanoparticles, their complexes and composites will be necessary for new technologies along with graphite nanotubes and fullerenes. Our methods of synthesis and selection of matrixes do not allow us as yet to synthesize only one morphological kind of above nanoparticles.



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Session B

Monday, Sept., 11, 2006 15:00 – 17:00

Chairman

Prof. A. Shamaa Prof. Z. Haiba



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B1 Preparation of Nd:YAG Powder by

sol-gel Method in Comparing with Solid State Reaction.

*Jahangir Hasani Barbaran, Fereshteh Hajiesmaeilbeigi

Solid State Lasers Div., Laser Research Center,Telefax:88008592

Tehran, P.O.Box:11365-8486 Iran.

Nd:YAG (Nd doped Y3Al5O12) single crystals are widely used in solid state lasers. The method of growing these single crystals requires long process time and high level of experience and has limitation of crystal size. Therefore recently preparation of transparent Nd:YAG ceramic has been propounded. In this work sol-gel method was used for synthesizing Nd:YAG powder which can be sintered to transparent ceramic Nd:YAG. The XRD analysis of prepared powder by sol-gel method showed that the YAG single phase is resulted by heat treatment at 900 C for 2 hr and crystallization is completed by increasing time or temperature. By SEM, micrographs of the synthesized samples and also homogeneity of Nd distribution in the YAG lattice was observed. Also in this work XRD analysis showed by solid state reaction method, temperature of 1350 C for 40 hr was not sufficient for obtaining YAG single phase.

* [email protected]



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B2 A New Materials Testing Technique

Based on Laser Produced Plasma Emission

Mazin M. Elias *

Institute of Laser for Postgraduate Studies, University of Baghdad, P.0. Box 47314 Jadiriah, Baghdad, IRAQ

* e-mail: [email protected]

Various modern techniques to test and analyze materials content are now

available, such as the flame atomic absorption, x-rays and neutron diffraction, transmission electron microscope (TEM) and electron spectroscopy in chemical analysis (ESCA). Each of these techniques has certain applications and limitations. In this work, an accurate and quick material testing technique is introduced. It includes the measurement of the intensity of electromagnetic emission from the plasma produced as a result of interaction of laser with the material under test. It is based on the following observation; When the material composition is slightly changed, a considerable change in its thermal conductivity occurs and the emission intensity of produced plasma is significantly altered. The latter parameter was measured with high precision using an ultra-high sensitive photon detection and counting system. The measurements were performed with a few joules Nd: glass laser system with a suitable stainless steel vacuum chamber specially designed for the present project. Sets of metals and alloys (with variable concentration of constituents) were used. The results demonstrate the capability of the present technique as a new nearly non-destructive tool for material testing with performance better than other testing techniques.



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B6 Porous Silicon: Properties and Applications

Farid A. Harraz*

Central Metallurgical R&D Institute (CMRDI)

P.O. Box: 87 Helwan, Cairo 11421, Egypt * [email protected]

Porous silicon (PS) is a versatile electronic material usually prepared by the galvanostatic anodization of single crystalline silicon wafers in fluoride-based solutions. The porous structure is similar to a network with a pore diameter ranging from few nanometer up to several micrometer, depending on the preparation conditions and the characteristics of the starting silicon substrates. The PS surface, on the other hand, is terminated by hydrogen and has an extremely large surface to volume ratio. Further, the material can emit a visible light at room temperature, a property that not found in bulk silicon. These properties and others can be used in various technological applications. In the present work, we show that various arrays of pores with different morphologies can be obtained in silicon by controlling the anodizing conditions and appropriate selecting the dopant type and level of the silicon. The surface modification of as-formed PS with different materials will also be addressed. The fabrication, characterization and possible applications of the PS layers will be demonstrated and thoroughly discussed during presentation.



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B4 Study on Photocatalytic Oxidation of Indigo

Carmine Dye on Mn-Supported TiO2

Reda M. Mohameda , Ibrahim Othman Alib*, Ibrahim A. Ibrahima

a Central Metallurgical R&D Institute, Department of Nanostructured

Material, Helwan, Cairo, Egypt. bFaculty of Science, Chemistry Department, Al-Azhar University, Nasser

City, Cairo, Egypt. *[email protected]

10 wt. % of manganese, ions in nitrate form was supported on titania prepared by sol–gel and impregnation methods. Specifically, the obtained catalysts were treated thermally at 500ºC and then characterized using XRD, FTIR and N2 adsorption measurements. The electrical conductivity has also been measured by applying Zeta potential technique to attain the effect of Mn supported on TiO2. Analysis of anatase-rutile phase transformation in TiO2 showed increased upon the addition of Mn. These materials were tested for discoloration (adsorption) and mineralization (in the presence of UV irradiation) of indigo carmine (IC) dye. The experimental results show that Mn/TiO2-imp is the highest photocatalytic activity. The influence of pH, catalyst amount and time on the decolorization rate of IC on Mn/TiO2-imp was thoroughly investigated and correlated with ZPC of MnOx species, various exposed species of MnOx and surface properties.



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B5 X-ray and Infrared studies For NiSiX Fe2-XO4

Ferrites

D.M. Hemeda, and M.Z. Said

Physics Department, Faculty of Science, Tanta University, Egypt

A spinel ferrite of the system NiSixFe2-XO4, with (x=0, 0.1, 0.2, 0.3, 0.4,

0.5) where studied via IR, X-ray spectra and cation distribution. The x-ray pattern confirmed the spinel cubic structure of all Si contents. The lattice parameters estimated as a function of Si contents a slight decrease of lattice parameter up 0.2. The grain size increases with increasing Si content up to 0.3 and then decreases for higher content. The jump length of electrons decreased with Si concentration up to 0.2. Four absorption bands were observed in infrared spectra in the range between 1000 and 200 cm-1. These bands are assigned to Fe3+ and Si4+ at the A and B sites The two high frequency bands in the range 580-555 and 450-400 cm-1 is assigned to υ1 tetrahedral (A site) and υ2 (B site).



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B6 IR irradiation Effects on Metals

*Anwar Latif, M.Khaleeq-ur-Rahman, S.M.Rafique, K.Bhatti,

Aisha Ahsan “Department of Physics”

University of Engineering & Technology Lahore Pakistan 54890 [email protected]

The work presented in this paper is a comprehensive study for the exploration and investigation of topographical, structural and surface morphological changes when the most significant conducting metals Gold, Silver and Copper are exposed to IR radiations. For this purpose an Nd: YAG laser (1064nm, 1.1MW, 12ns) has been used to irradiate fine polished and annealed samples of these materials for an optimized number of laser shots. The surface analysis has been made on the basis of images and patterns obtained using SEM, XRD and Metallurgical microscope. Laser ablation caused boiling, splashing and exfoliation along with other relevant phenomena, all were observed through SEM micrographs and have been discussed in detail. The XRD patterns of the exposed metal samples clearly indicate a change in intensity and disturbance in atomic planes caused by the defects produced as a result of energy transmission by IR radiation to metal surfaces. The information collected provides a significant addition in the knowledge to investigate the complexities found in IR radiations- metal interactions.



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B7 RDF Analysis, Positron Annihilation and Raman Spectroscopy to Study the Structure of Nonlinear

Optical xTiO2 – (60 – x) SiO2 – 40Na2O Glasses

A.Abou Shama*, F.El-Diasty and M.S.Abd El-Kareem

Physics Department, Faculty of Science, Ain Shams University 11566 Abbassia, Cairo, Egypt.

*E-mail: [email protected]

xTiO2 – (60 – x) SiO2 – 40Na2O glasses have proven an interesting

nonlinear optical properties [1,2]. The investigated glasses show one order of magnitude enhancement over some TiO2 silicate glasses. In this work, we continue studying these glasses using different techniques to analyze the glass structures seeking to provide a deep insight for the relation between structure, compositions and the optical characteristics of these glasses. The Radial Distribution Function (RDF) analysis combined with positron annihilation and Raman spectroscopy are used to study these glasses. The origin of the non-bridging oxygen (NBO) bonds has been traced correlating their existence with the measured nonlinear optical properties of the investigated glasses.



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B8 Vibronic Reduction Factors in Cubic and

Icosahedral Systems

Dr. Faten E. Al-Hazmi

Physics Department/ King Abdualaziz University

Second-order reduction factors (SORFs) are important as they can

generate contributions to the effective Hamiltonian which may be significantly larger than and different from those of first order. It can be act as a bridge between experimental data and basic theory. This work is divided into two parts: In part I a new general method is developed to determine the vibronic second-order Jahn-Teller (JT) reduction factors (RFs) in terms of the strength of the vibronic coupling for systems in which electron orbital degeneracy or pseudo-degeneracy exists. These include in particular the fullerene molecule 60C , pseudo-Jahn-Teller molecules and impurity centres in crystals. Hence studies of the JT effect are important in understanding the properties of

60C and related molecules. In part II an analytical values for the second-order RFs are calculated by using non-Condon corrections to the standard FC calculations for cubic and icosahedral systems. The validity of this non-Condon correction approximation is first tested in the cubic 2tT ⊗ JT system due to its relative simplicity. It is found that the results are closer to those obtained earlier by numerical methods than the analytical FC values alone. Moreover, the results of this work have proved that the non-Condon correction is valid from very strong vibronic to intermediate strength coupling limit for gu hT ⊗1 JT system,

)( hgG ⊕⊗ JT system and )( hgH ⊕⊗ JT system. The previous work has demonstrated that such an approach can give values for the RFs close to those deduced form experiments.



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B9 TEM Investigation of Amorphization Kinetics due to Argon

Implantation in GaAs

K. Akmoum1*, A. Claverie2, M. Mimi1 and G. BenAssayag2

1 Département de physique, Université de Mostaganem 27000, Algerie. 2 CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse cedex, France.

* E-mail: [email protected]

The design of semiconductor devices is based upon the ionic

implantation, which is widely used for integrated circuit. Ion implantation allows to selectively create either doped or high resistive regions in materials. We investigated the crystalline to amorphous transition induced by ion implantation in GaAs using transmission electron microscopy (TEM). Samples of GaAs were implanted at both 100 K and room temperature with 40 keV Ar+ and with doses between 2×1013 and 5×1014 ions/cm². Experimental results are discussed in term of the deposited energy density, which has been determined using Monté Carlo simulation developed from IPROS. Values of 15 eV/mol [3.3×1023 eV/cm3] and 10 eV/mol [2.2×1023 eV/cm3] have been obtained for the threshold energy damage density at room temperature and low temperature implantation. The amorphization mechanisms of GaAs under ion implantation are discussed in light of these results.



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B10 Ion Irradiation of Silicon

M. Khaleeq-ur-Rahman*, M. S.Rafique, Khurshid Aslam, Javed

Safdar, S.Rizwan,

Department of Physics, University of Engineering and technology, Lahore,54890, Pakistan

Presenting Author: M. Khaleeq-ur-Rahman Email: [email protected]

The aim of this research work is to study the changes produced in silicon after laser produced ion irradiation. A pulsed Nd:YAG laser (having energy 10mJ, pulse duration 9-12 ns and power 1.1MW) is used to produce Gold ions which were irradiated on silicon. XRD pattern of silicon are taken after ion irradiation in air and vacuum for 300 and 200 shots, respectively with the help of X-Ray Diffractometer. A comparison of these patterns with the standard pattern of un-irradiated silicon reveals that the intensity of diffraction lines in XRD pattern increased after ion irradiation. This clearly indicates that during the ion target interaction, atoms are displaced from their normal positions. SEM micrographs of gold ions irradiated Silicon not only provides evidence of heat conduction in the localized focused region but also the production of thermal spikes in the silicon sample. The results of the research work may be utilized in industry, electronics, surface modification, surface hardening, material processing, medical, defense and sensor development.



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B11 Laser Irradiation of Silicon

Khurshid Aslam*, M. Khaleeq-ur-Rahman

M. S.Rafique, Javed Safdar,

Department of Physics, University of Engineering and technology, Lahore, 54890, Pakistan.

Presenting Author: Khurshid Aslam Email: [email protected]

The aim of this research work is to study the changes produced in silicon after pulsed Nd:YAG laser (energy 10mJ, pulse duration 9-12 ns and power 1.1MW) irradiation in air and vacuum for 25, 50 and 75 shots. The surface modification was stuied with the help of SEM micrographs. Gradual build up of periodic damages and differaction patterns are observed. Also cracks formation, redeposition of material, droplets, globules, cones, shock affected zone, ripples. This conforms the laser ablation and sputtering of silicon. The results may be used in industry, electronics, surface modification, material processing, medical, defense and sensor development.



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B12 SEM and XRD Analysis of the Laser Irradiated

Cadmium

M. S. Rafique, M. Khaleeq-ur-Rahman, Khurshid Aslam, Tayyaba Firdos,

Department of Physics, University of Engineering and Technology,

Lahore, Pakistan, 54890 Presenting Author: Dr. M. Shahid Rafique Email: [email protected]

A pulsed Nd: YAG laser (10mJ, 12ns, 1064nm) was employed to study the IR irradiation effects on the metallic samples of Cadmium. The laser was irradiated for 100, 200, and 300 shots under vacuum ~10-3 torr. The results were investigated using Hi Tech S3000H Scanning Electron Microscope (SEM) and X’pert Pro PANalytical X-ray Diffractometer (XRD). The micrographs obtained from SEM revealed that the surface morphological changes have occurred in the form of crater. The forward expansion of plasma into an ambient gas coupled with the recondensation of the target surface results in the formation of debris. Large temperature gradients produce variations in the thermal resistance that leads to the distributed shape of the heat affected zone. The hydrodynamic effects are apparent with liquid flow to form the recast material around the periphery of the laser focal area. The turbulent resolidified material is formed when surface asperities are accelerated away from the liquid surface during each laser pulse due to melting followed by thermal expansion of the liquid. The positive feed back of the repeated pulses resulted in the form of ripples. Grains appear on the surface as an evidence of heterogeneous nucleation. The confirmation of the formation of these structures has been done by X-ray Diffractometer (XRD). The results of the study will be employed in the industry, defense and material processing.



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Session C

Monday, Sept., 11, 2006 17:30 – 19:30

Chairman

Prof. S. Mazen Prof. M. Zaidia



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C1 Electrical and Magnetic Properties of

RxY1-xBa2Cu3O7-δ (R = Nd and Er) Spin Glasses

N.A. El-Shishtawi, A. Tawansi, H. Makram1, and S.I. Badr,

Dept. of Physics, Faculty of Science, Mansoura University, 35516, Egypt 1 LMOS, CNRS ER178, 1 place A. Briand, F-92195 Meudon Principal

Cedex, France,

The effects of partial replacement of R (= Nd and Er) by Y of the physical properties of the systems RxY1-xBa2Cu3O7-δ were investigated. The concerned properties were X-ray diffraction, ac and dc magnetic susceptibilities and electrical resistivity. For Nd doping levels of 0.0 ≤ x ≤ 0.3 an orthorhombic crystalline structure was identified while a tetragonal structure was found for 0.4 ≤ x ≤ 1.0. A spin glass character was obtained for Nd doping ≥ 0.3. The destruction of superconductivity was ascribed to the low value of the crystal parameter c and the lattice strains due to the difference in the radii of Nd and Y. A tetragonal structure was obtained for Er doping of 0.0 ≤ x ≤ 0.3, while an orthorhombic type was identified for 0.4 ≤ x ≤ 1.0. The ac susceptibility temperature dependence revealed a spin glass character, while a Curie — Weiss behaviour (with a low effective magnetic moment) was found. The observed Arrhenius temperature dependence of the electrical resistivity exhibited a serniconducting order in the temperature range of 100-191 K.



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C2 Local Moments in Mn-Pd Compounds

R. Pacurariu*1, M. Coldea1, M. Neumann2, V. Pop1, L.G. Pascut1

1 Babes-Bolyai University, RO-400084 Cluj-Napoca, Romania 2 University of Osnabruck, Fachbereich Physik, D-49069 Osnabruck, Germany

The problem of local moments confined to the transition metals sites, i.e., localized behaviour in some aspects of itinerant electrons, is one of the most important issues in the physics of the magnetic alloys and intermetallic compounds. In the phase diagram of the Mn-Pd system there are three regions of solid solubility which comprise also four intermetallic compounds: MnPd3, Mn11Pd21, Mn3Pd5 and MnPd. We study the electronic structure of Mn-Pd compounds using X–ray photoelectron spectroscopy and discuss the results in relation with their crystallographic and magnetic properties. Earlier neutron diffraction measurements pointed out that Mn-Pd compounds order antiferromagnetically with Néel temperatures and magnetic moments on Mn sites ranging from approximately 200 to 825 K and 4 to 4.4 µB, respectively. By correlating our susceptibility measurements with the neutron diffraction studies we prove the existence of local magnetic moments also on the Pd sites and the participation of these atoms in the magnetic exchange interactions. The electronic structure of Mn-Pd compounds are studied by analyzing the valence band and core level spectra. The most important feature of the observed spectra is the well-defined magnetic exchange splitting of about 1.15 eV of the Mn 2p3/2 lines, arising from the exchange interactions between the core hole and open 3d shell. This gives a clear evidence of the existence of local moments in the Anderson’s sense confined on Mn sites in Mn-Pd compounds. After background removal the spectra were fitted using four components and a satellite line. The relative intensities of the components vary depending on the Mn environment, reflecting the changes in the properties of the Mn 3d states. Our previous band structure calculations revealed that there is always Pd 4d character in the valence bands above EF. The valence band spectra for Mn-Pd compounds are dominated by the Pd 4d states, since the cross section for Pd 4d is about eleven times larger than for Mn 3d. The valence - band centroids are shifted towards higher binding energies, the density of states (DOS) at the Fermi level decreases and a shoulder at EF becomes visible as the Mn concentration increases, suggesting a gradually filling of the Pd 4d band. This behaviour is attributed to the hybridization of the Mn and Pd states.



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C3 Structural and Magnetic Properties of (Ni (1-X) MgX)

Fe2O4 Ferrites

A. Al-Sharif* and M. Abo-AlSondos

Dept. of Physics, Mu’tah University - JORDAN

We have studied the structural and magnetic properties of (Mg Ni)- Fe2O4 Ferrite. X-ray diffraction and magnetization measurements were performed for all samples. X-ray results that a single phase ferrite was obtained for all samples. The lattice parameters were estimated from the x-ray results. The X-ray results showed that the lattice parameter increases at high Mg2+ contents (x ≥ 0.4) in comparison with the lattice parameter of the base sample (Ni Fe2O4). Magnetic hysteresis measured for all samples showed that the coercivity decreases at higher Mg2+ contents (x ≥ 0.4) in comparison with the coercivity of the base sample (Ni Fe2O4) coercivity. It was found that the saturation magnetization (Ms) and the remanence (Mr) decreases for all the studied samples (with increasing Mg).



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C4 Investigation of the Preparation Process and

Composition of the Superconductor Bi1.6Pb0.4Sr2+xCa2+YCu3O10+ä

Mahdi H.Suhail, Matti N. Maqadsi and Samir Adnahn Rahma Al-Taie

Dept. of physics, college of science, univ. of Baghdad

E-mail [email protected]

The aim of the research is to prepare pellets from Bi1.6Pb0.4Sr2+xCa2+yCu3O10+ä (x=0, 0.1, 0.2; y=0, 0.1, 0.2) superconductor compound by direct synthesizing method (DSM) which retern to solid state reaction. Pellets of Bi1.6Pb0.4Sr2+xCa2+yCu3O10+ä were prepared from Oxides, Carboniets, and Nitrates of starting materials in proportion to their molecular weights. The prepartion conditions were constant (pressing pellets at 5Ton, diameter 13mm, thickness 1.5mm, sintering temperature 860oC, with twice sintering time at 120h and regrinding.

The results of x-ray diffraction (XRD) tests for all samples showed that the compound contains two main phases; High-Tc Phase (HTP) and Lwo-Tc Phase (LTP) or more as for the samples that have high ratios of Sr, especially the ratio x=0.2 ; y=0.2. From the electrical properies of all samples, we noticed that the compound have the maximum critical temperature Tc=100K for the ratio x=0.1 and y=0.1, [and it has orthorhmbic structure with domination in crystalline direction for high phase at H(1013)] while Tc=85K for the ratio x=0 and y=0. The increase in the Ca content has positive effect on superconductive properties while the Sr content destroied the superconductivity at x=0.2 and y=0.2, 0.1, 0. We did not obtain the single HTP, thus we used the multi-grinding method for the sample Bi1.6Pb0.4Sr2Ca2Cu3O10+ä with sintering temperature 860oC, and sintering times (100h, 150h, 200h, and 240h) and regrinding for each stage.The results of XRD analyses showed that the compound prepared by multi-grinding has also two phases: HTP and LTP. The oxygen content of this sample was ä=0.44 and critical temp. Tc=100K while for the single grinding [x=0, y=0 which is prepared previously (sintered at 240h with single regrinding in the mid of the operation)] was ä=0.37 and Tc=85K. We did not obtain the single HTP, thus we used different preparation methods for the sample Bi1.6Pb0.4Sr2Ca2Cu3O10+ä. These methods related to solid state reaction. The first method is Two-Step



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Method (TSM), where the compound Bi1.6Pb0.4Sr2Ca2Cu3O10+ä sintered at 860oC for 200h (with twice sintering time at 100h and regrinding). The results of XRD analyses showed that the domination of HTP and also the crystalline direction at H(0016) with low ratios of LTP at L(105) and L(0012). The sample had orthorhmbic structure with c=37.8A. From iodemetric titration tested that ä=0.4 and from electrical properties, we found that Tc=105K. The second method is Multi-Step Method (MSM) where the compound Bi1.6Pb0.4Sr2Ca2Cu3O10+ä prepered at sintering temperature of 860oC for 100h with twice sintering time at 50h and regrinding. The results of XRD analyses showed that the compound is single HTP, its lattice constant is c=38A with orthrohmbic structure and growth towards the phase H(002) and H(0014), it has ä=0.55. The results of electrical tests show that the critical temp. is Tc=113K and the transition region width is ÄTc=27K, the matter that indicates the growth of the single high-Tc phase. We used the X-Ray Floursent (XRF) analyses to test the proportions of the elements constituting compound. We compared between the preparation methods and the effect of sintering time (more than 150h) on the loss of the elements constituting the compound. We noticed that in the cause when we had no growing in HTP is due to the loss in the main elements (Bi, Cu) during the longer sintering process. MSM was considered the ideal method to the complete growth high-Tc phase.



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C5 Thermal Properties of High Temperature

Superconductors Within Ginzburg Landau Theory

L.N. Shehata*, A.Y. Afram and H.M. Taha

Department of Mathematics and Theoretical Physics Atomic Energy Authority, Cairo, Egyp.

e-mail: [email protected]

A mathermatical treatment of the thermodynamics of high temperature

superconductors was considered in the frame of the conventional and the modified Ginzburg-Landau theories. The Ginzburg-Landau free energy was rewritten in a form that expresses the physical quantities of the thermodynamic critical field Hc(T), the coherence length ξ(T) and the penetration length λ(T) of the superconductor. For the sake of possible modifications in Ginzburg-Landau energy, selected temperature-dependent formulae for the coefficient parameter α(T) were considered. Our calculations show that the derivatives of the free energy with respect to the temperature T, the entropy S, the specific heat C and its temperature derivative

TC

∂∂ are continuous functions through the phase

transition. Comparisons with available data are presented.



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C6 Metal Induced Effects in the Optical Chracteristics

of Se8Te2 Amorphous Alloys

G.A.M. Amin*, E. Borham*, A.F. Maged* and Y. Badr**

National Center for Radiation Research and Technology (NCRRT), P.O.Box 29, 29 – Nasr City, Cairo, Cairo Uinversity.

National Constitute for Laser Enhanced Science (NIIES).

Optical measurements were performed on thin amorphous chalcogenide

films from from the systemof pure (Se8Te2) and metal doped (Se8Te2)0.9M0.1 (M= Cu, Sn and Ag). Bulk Se8Te2 alloy was prepared by the standard melt quenching technique and the different metals were added to the binary using the same technique. Thin films of the prepared compositions was grown using thermal evaporation method. The effect of different metallic additions on the optical characteristics was explored. The effect of annealing at a temperature below the glass transition temperature Tg on The optical behaviour was also explored. The optical energy gap E0 was found to decrease with the addition of metal, the amount of decrease depends on the chemical character of added metal. Annealing leads to a decrease of the optical energy gap with annealing time.



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C7 The Effect of the Metal Additives on the Physical

Properties of Amorphous Ge(SxSe1-x)2

S.A. Fayek, M.A. Soliman*, M.R. Balboul and M.M. Ibrahim

National Center for Radiation Research and Technology, Cairo, Egypt. *Faculty of Science Cairo University, Cairo, Egypt.

UV-VIS transmission, X-ray diffraction and DC electrical conduction

were used for characterization of film properties of amorphous Ge(Sx Se1-x)2 with x = (0.0, 0.12, 0.44, 1). Thin films of Ge(SxSe1-x)2 modified by the addition of metallic Ag(Cu) were prepared by thermal diffusion (TD) of the metal inside the host films. The metal concentration of the prepared films ranged between 5 and 35 at. %. The kinetic studies of TD revealed that the value of the TD rate for Cu is greater than that for Ag. The addition of metal increases the absorption coefficient in the power-law regime and consequently the optical gap decreases and the refractive index increases. The band-tail width (Ee) slightly increases at low metal concentrations, then it decreases with increasing concentration of metal. The X-ray diffraction patterns of Ge(SxSe1-x)2 show a decrease in the intensity of the first sharp diffraction peak (FSDP) upon adding Ag and become negligible upon adding nearly the same concentration of Cu. No crystalline peaks appear (the amorphous nature is still present) at high concentration of metal, which is consider as an advantage of the (TD) process. The FSDP disappear by adding Ag metal at concentration of about 25 at. %.



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C8 Differential Scanning Calorimetric Study of

Ge0.15As0.20Te0.65 Chalcogenide Glasses

E. R. Shaaban*, A. M. Abousehly, and Yasser. B. Saddeek

Physics Department, Faculty of Science, Al-Azhar University, Assiut - Egypt.

Results of differential scanning calorimetric (DSC) under non-isothermal condition of bulk amorphous semiconducting alloys of Ge0.15As0.20Te0.65 glasses with different heating rates are reported and discussed. The glass transition temperature, crystallization temperature at different heating rates and structural change during glass transition have been determined from an empirical relation. The dependence of the glass transition temperature (Tg), crystallization temperature (Tp), the activation energy for structural relaxation (∆Et), the activation energy of crystallization (∆E) and the Avrami index (n) are calculated at different heating rates the Avrami index is calculated from the relationship between crystallization rate versus temperature. On the basis of the obtained experimental data, the thermal stability (∆T) and the resistance to devitrfication after the glass formation are also determined.



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C9 Modification of Selenium-Tellurium Amorphous

Composition With Iron using the Mechanical Alloying Method

G.A.M. Amin

National Centre for Radiation Research and Technology, P.O.Box 29-Nasr City, Cairo, Egypt

e-mail:[email protected]

The mechanical alloying method was used to add Fe to the amorphous

Se8Te2 alloy. The effect of mechanically alloying Fe with Se8Te2 on the optical properties of thin films of the resulting alloys was studied in the UV-VIS spectral region. Different models for the determination of the optical energy gap were reviewed and used to analyze the obtained data. The optical energy gap was found to increase with the Fe content. Values of the optical energy gap of the alloys under investigation were determined using three different methods and the relation between different measures of the optical gap is explored. The effect of annealing at temperatures below the glass transition temperatures was also investigated. The optical energy gap found the decreases with the annealing time revealing the increase of randomness as a result of thermal annealing.



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Session D

Monday, Sept., 11, 2006 17:30 – 19:30

Chairman

Prof. M. Amin Prof. M. Ali



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D1 Pysical Properties of Methylecellulose Polymer at

different doses of γ- irradiation.

Ismail M. Hamada

Physics Department, Faculty of Science, Tanta University, Tanta, Egypt

IR speectral analysis were carried out for irradiated and unirradiated of methylecellulose sample using 60Co γ-rays between 1-4 mega rad. The refractive index was estimated from IR analysis. It was observed that the refractive index decreases to minimum value for 1 mega rad irradiation and then increases for higher doses. The dielectric constant increases for 1 mega rad radiation and then decreases. This was attributed to the more dipole orientation in one direction for one mega rad. The electrical resistiveity decreases with increases tempreature. The change of the Physical parameters of the sample of irradition helps the human being to use these polymers as a sensor for detecting nuclear pollution.



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D2 Correlation of Swelling Properties of Some

ã- irradiated Hydrogels With Variations in Nano Free-Volumes Using

Positron Annihilation Spectroscopy

M. Mohsen1, E. Gomaa1, E. Hassan Aly1, El- Sayed .A. Hegazy2 , Gh. A. Mahmmoud2

1 Physics department, Faculty of Science, Ain Shams University, P.O.

Box 1156, Abbassia, Cairo, Egypt. 2 National Center for Radiation research and Technology, P.O. Box 29,

Nasr City, Egypt. e-mail: [email protected]

Positron Annihilation Spectroscopy (PAS) has been used to investigate the effect of gamma irradiation on the free-volume holes at the atomic scale of hydrogels derived from acrylamide (AAM) and acrylic acide (AAC). Free-volume parameters have been measured from ortho-positronium (o-Ps) lifetime and the S-parameter of Doppler broadening spectra from annihilation radiation as a function of ã-irradiation dose. The samples have been irradiated at room temperature with doses ranging from 5 - 40 KGy. At low radiation dose a significant decrease in free-volume size (Vh) is observed followed by an increase at high dose. On the other hand, the fraction of free-volume (f %) increases with dose up to 20 KGy followed by a steep decrease up to 30 KGy then a smooth increase up to 40 KGy. These results are supported by a significant variations in the free-volume hole size distributions. In addition a correlation between the free-volume parameters (Vh & f %) and water up take is established.



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D3 Some Sulfated Water Soluble Natural Polymer

(Carrageenans) Compounds as Corrosion Inhibitors for Dissolution of Iron in Hydrochloride

Solution

K.S. Khairo and I. Zaafarany

Chem. Dept. Faculty of Appl. Sci, Umm Al –Qura University. Makkah Al Mukaramha. Saudi Arabia Email : [email protected]

The effect of some sulfated water soluble polymer (Carrageenans) compounds on the corrosion behavior of iron electrode in 1M hydrochloric acid solution as corrosive medium has been investigated using galvanostatic polarization technique. Some corrosion parameters such as anodic and catholic Tafel slope, corrosion potential, corrosion current density, surface coverage and inhibition efficiency was calculated. The polarization measurements indicated that the inhibitors are mixed type. The inhibition efficiency was found to increase with increasing concentration and number of sulfer atom per molecules. Inhibition was explained on basis of parallel adsorption of these compounds on the iron electrode. The adsorption process follows Langmuir adsorption isotherm.



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D4 Thermodegradation Kinetics Studied of

Arylhydroxy, Carboxy and Antipyrine Acrylate Polymers

F.M.Al-Nowaiser, E.H.El-Mossalamy and K.S.Al-Thabaiti

Chemistry Department,Faculty of Science King Abdul Aziz University

P.O.Box 80203 Jeddah 21589 Saudi Arabia

Monomers of, o-Aminophenol, Anthranilic acide and 4-Aminoantipyrine with Acrylic, methyl acrylic and methylmethacrylate have been synthesized. Metal complexes of the polymers were prepared from chloride salts in ethanol. Characterization of the polymer and its complexes was made by microanalyses, Ft-IR, 1H-NMR and UV-vis spectroscopy and thermogravimetric analysis. The activation energy of the decomposition of these systems were evaluated by the integral method developed by Flynn- Wall- Ozawa and by Coats and Redfern method. The kinetic parameters have been used to estimate the lifetime of systems. The obtained results confermed the modification of the thermal stabilities of polymer complexes.



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D5 Preparation of Acrylat Oligomers Microstructure by Electron Beam Curing to Approach the Degree

of Water Wetting

Nabil A. El-Kelesh and Nabila A. Maziad

National Center for Radiation Research and Technology, Atomic Authority, Nasr City P.O.Box 29, Cairo, Egypt, 113701.

Measurement techniques that quantify the degree of water wetting are

important for the communication of research findings. The water drop penetration time (WDPT) is a commonly used measurement. If a water drop was fixed on the surface of the modified polyethylene terphethalate (PET) polymer, the water contact angle would be lower than 90o and the surface is considered to be water wetting. The adhesion force was determined by the degree of scratching, aberration and toughness force. The resistance of the surface toward to polar and non-polar organic solvents was studied. Acid and alkaline resistances of the acrylate cured surfaces were investigated. Characterization of the prepared cured surfaces depends on the hydrophilicity of both monomer and oligomer used, the curing process was applied using electron beam irradiation at different doses ranged from 10-100 kGy. The crosslinking of monomer with both oligomer and polymer substrate through the acrylate bond was studied by Ramman and FTIR spectroscopy. It was found that, the degree of crosslinking depends on the concentration of hydrophilic monomer and oligomer selected for our purpose. The permeability, x-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) were studied to show the quality of the surface morphology of the cured polymer. Thermal stability and its resistance to the heat effect of the modified polymer was investigated using Thermogravemetric Analysis (TGA) and Differential Scanning Calorimetric (DSC) techniques.



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D6 Electrical conductivity of 4-tricyanovinyl-N,N-

diethylaniline

M.M. El-Nahass, K.F. Abd-El-Rahman*, A.A.A. Darwish

Physics Department, Faculty of Education, Ain Shams University, Roxy Square 11757, Cairo, Egypt

The characterization of 4-tricyanovinyl-N,N-diethylaniline, TCVA, have been reported. TCVA was characterized by using DSC, FTIR and two-probe conductivity measurements. The DSC measurements of TCVA showed that the compound is stable up to 150oC. The temperature dependence of electrical conductivity, in the temperature range from 298 to 403 K, was studied on pellet samples of TCVA with evaporated ohmic Au electrodes. The electrical conductivity was found to be 8.30×10-12 Ω-1.cm-1 at room temperature. The temperature dependency of the electrical conductivity is typical for semiconducting compounds and suggested that there were two types of conduction channels contributing to conductivity. This compound exhibited conformational change upon electronic excitation (S0→S1) depending on the elevated temperatures.



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D7 Synthetic Rout, Thermal Kinetic and, Electrical

Conductivities Studies of Some Organotin Polymers

Shaeel A.Al – Thabaiti and Rihab F. Angawi

Chemistry Department Faculty of Science King Abdulaziz University. P.O.Box 80203 Jeddah 21583 SAUDI ARABIA

New synththetic route to prepare some organotin polymers based on N- substituted acrylamide and methylacrylamide acid esters via a new synthetic route tri-butyltin - α - bromoarylate monomer (TBTBA) was prepared and polymerization carried out. Organotin polymers were prepared via the new synthetic route by exchange reactions.Tri – n- butyltin - α - bromoacrylate monomer (TBTBA) was prepared by reaction of tri – n- butyltin oxide with α - bromoacrylic acid. Polymerization of (TBTBA) was carried out in solution at 70 oC using azobisisobutyronitrile (AIBN) as initiator and dimethylformamide (DMF) as a solvent. Organotin polymers based on N- substituted acrylamide and methacrylamide were prepared via new synthetic route by exchange reaction of poly- N-acryloyloxy-and poly- N-methacryloyloxypthalimides with o-, m- and p- aminotrin-butyltin benzoates. The thermal decomposion and kinetics reactions of organotim polymers were studied, and the activation paramelers for each decomposition step were calculated and discussed.The Electrical properties are studied under which the variation of electrical conductivity with respect to temperature is obtained and type of chargecarriers is determine electrical resistivity of the sample can be measured. Prepared organotin polymers have good film properties, and are suitable for film formation.



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Session E

Wednesday, Sept., 13, 2006 15:00 – 17:00

Chairman

Prof. S. Abd El-Moteleb Prof. N. Shaalan



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E1 Optical Behaviour and Related Properties of the

Binary Mixture 5cb/8cb Liquid Crystals

M. Roushdy*

Physics Department, Faculty of Science, University of Cairo.

The index of refraction in the isotropic phase, n, and in the mesophase, no, for pure 5CB and 8CB liquid crystals as well as their binary mixtures, were measured as a function of temperature. The related parameters; namely, orientational order parameter (S), relative polarizability anisotropy (ζ) and molecular length-to-breadth ratio (k), were calculated and compared for the mesophase of the considered samples. The order parameter and the relative polarizability anisotropy had maximum values for the binary mixture having eutectic composition. The low values observed for the k-parameter, either for pure or mixed states, suggest the arrangement of parallel molecules within the nematic phase persists in groups “swarms”.



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E2 Optically Illuminated 4H-SiC THz IMPATT Device

M. Mukherjee and N. Mazumder

Department of Applied Physics International Institute of Information

Technology Visva Bharati University X-1, 8/3, Block EP, Sector V

Salt Lake Electronics Complex, Kolkata 700091, INDIA e-mail: [email protected]

The terahertz (THz) regime (0.1-10 THz) is rich with emerging

possibilities in remote sensing, imaging and communications, with unique applications for detecting hidden biological weapons and explosives. There is an emergent need for developing solid state high power THz sources. IMPATT devices are found to be the most efficient solid state sources that can deliver highest RF power even at 300 GHz. Due to excellent material properties, 4H-SiC IMPATTs are likely to produce 400 times RF power (PRF ) than Si & GaAs counterparts. The small signal characteristics of a flat 4H-SiC DDR (p+pnn+) IMPATT operating at 0.5 THz are studied for the first time and the results are reported here. The diode design parameters are as follows: epilayer doping (p & n) = 9x1023 m-3, epilayer widths = 0.15 µm, current density = 6x109 Am-2, operating temperature = 300 K. The output data of the simulated diodes are: Maximum field = 2x108 Vm-1, Breakdown voltage (VB) = 96 volts, Efficiency (η) = 25%, Avalanche resonance frequency (fa) = 0.42 THz, Optimum frequency (fP) = 0.51 THz, Peak negative conductance (-GP) = 29x107 Sm-2, Quality factor (QP) = 2.0, RF power (PRF) = 2.5 W, assuming a diode chip of diameter 10 µm. Si and GaAs IMPATTs can not approach THz region due to the limitations imposed by their material parameters. Hence, no comparison is made with Si and GaAs IMPATTs. Optical control of microwave properties of the device is also studied. When an optical photon of appropriate energy is absorbed at the edges of the active layer of an IMPATT diode, additional electron-hole pairs are generated within the active region of the diode, which, in turn, enhance the existing thermal leakage current in the device. The enhancement of leakage current is manifested as the lowering of electron and hole current multiplication factors, Mn and Mp, respectively. It is found that -GP decreases (~30 %), while, fP shifts upwards (a maximum up to 50 GHz) and QP increases gradually with



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increasing leakage current. It is further observed that the upward shift in operating frequency is more when the diode performance is controlled by hole saturation current. The predominance of Mp over Mn in producing higher frequency shift in 4H-SiC IMPATTs may be due to inequality of ionization coefficients. These studies thus suggest that 4H-SiC DDR IMPATT is highly radiation sensitive THz power generator. The results may be utilized for developing optoelectronic THz sources.



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E3 Measurements of Mass Absorption Coefficients of

Multi Elements by XANES

M. H. Eisa a *, c, A. El -T. Sharaf el Din b, c, A. H. Sirelkhatim c

a Department of Physics, College of Science , Sudan University of Science and Technology, Khartoum 11115 , Sudan

b Department of Physics, Faculty of Science, University of Khartoum, Khartoum 11115 , Sudan

c Sudan Institute for Natural Sciences, Research Unit, Khartoum 11115 , Sudan

Measurements of nine elements between atomic numbers 22 to 30 have been made to determine the mass absorption coefficients (MACs). The MACs of the elements were measured in the energy range 4.93~9.69 KeV by the X-ray absorption near edge structure (XANES) technique. It is well known that, on the near edge absorption (NEA) of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. So that, there are only a few points of mass absorption coefficients at the NEA, and that always average value in published table. Our results showed a wide range of data. The investigation confirmed that XANES is a powerful technique for multi-element absorption coefficient measurement. Details of experimental methods and results are given and discussed. Our experimental results are compared with published data. Our results and the published data are in good agreement. This experimental work has been performed at Beijing Synchrotron Radiation (SR) Facility.



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E4 Simple method for ellipsometric measurements

M.M. El.Okr*, M. Akl **

* Faculty of Science, Al Azhar University

** Faculty of Engineering (shobra) Banha University

There are deferent types of ellipsometers some of them needs exact quarter –wave plate (λ/4) and others (λ/4) plate is not a must. Generally are (λ/4) plate can cover a narrow wave length range. In the present study the ellipsometric function ρ2 =R|| /R⊥ is used to estimate the optical constants. Starting with ρ2 = R|| /R⊥=[(a - sinθ tanθ) 2 +b2 ] / [(a + sinθ tanθ) 2 +b2 Where (a – i b) = (ε - sin2 θ) 1/2 and ε =(n –i k) 2 ,it is easy to show that k= z and n =

kab

. her Z = ½[ a2 – b2 + sin 2θ) + )sin22(sin)( 2222222 θθ +−++ baba a

=)()(

)1()1(

222

.tansin.[cos2costansin

⊥−⊥+

−⊥+⊥ −

−

RRRR

RR

ll

llθθθθθθ

b2= )1()1(22 cos2cos −⊥

+⊥−+ RRaa θθ set of

curves shows the dependence of z, a, b on the angle of incidence have been constructed at constant ρ. this was used to estimate the accuracy of the method.



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E5 Fabrication and Characterization of GaAs-Based Transceiver Chips for Bidirectional Optical Data

Transmission

Abdel-Sattar Gadallah*, Martin Stach, Fernando Rinaldi, Steffen Lorch, Ihab Kardosh, Philipp Gerlach, and Rainer Michalzik

Ulm University, Optoelectronics Department, D-89069 Ulm, Germany

http://www-opto.e-technik.uni-ulm.de/

Design, fabrication, and characterization of monolithically integrated transceiver chips operating in the Gbit/s range of data rates at 850 nm wavelength are reported. The transceiver chip consists of a vertical-cavity surface-emitting laser (VCSEL) and a directly adjacent metal–semiconductor–metal photodiode (MSM PD). The layers of the VCSEL as well as those of the MSM PD are grown by means of solid-source molecular beam epitaxy on an n-type GaAs substrate. Different processes such as dry etching, wet oxidation, bondpad metallization, and anti-reflection coating required for the manufacture of the chips are described. In static operation, the standard oxide-confined VCSELs with 9 µm active diameter have threshold currents and voltages of 1.7 mA and 1.65 V, respectively, and differential quantum efficiencies of 37 %. The photodiodes with 1 µm wide interdigitated electrodes separated by 2 µm wide spacings show 0.4 A/W responsivity and have a 3-dB bandwidth of 1.4 GHz at 250 µm diameter and 4 V bias voltage. The chip components thus enable even error-free 2.5 Gbit/s back-to-back data transmission since the VCSEL small-signal cut-off frequency exceeds 5 GHz. For bidirectional data transmission, one butt-coupled transceiver chip at each fiber end is utilized, i.e., there are no optics between the chip and the fiber. High coupling efficiencies of almost 90 % are obtained using a proper chip design. The data transmission experiments are performed in half-duplex mode, i.e., one VCSEL is modulated while the second VCSEL and both MSM PDs have a constant bias. Wide open eye diagrams for transmission of a non-return-to-zero pseudorandom bit sequence at 1 Gbit/s data rate over 10 m step-index multimode fiber with 200 µm core diameter have been recorded.



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E6 Identification of Inorganic Constituents of

Salvadora Persica Using Spectroscopic Techniques

Z. A. El Sayed

Spectroscopy Department, National Research Centre, Cairo, Egypt.

SALVADORA persica chewing sticks, Misswak used for oral hygiene in the Moslem Countries, are believed to contain chemical substances which inhibit plaque formation(1). In recent years the toothpaste made from salvadora persica chewing sticks has become available to the general public. The antiplaque effect of the toothpaste containing salvadora persica compared with chiorhexidine glyconate has been studied by several workers (2,3). The organic and inorganic compositions of the sticks have also been investigated. Massaati et a!.(2) reported that, scanning electron microscopy of the surface of the chewing sticks showed that, in the unused state the vegetal bristles of the arrak roots (salvadora persica) are distributed very irregularly, and the extremities of the fibers are not rounded but very torn out.(4,5) This irregular aspect becomes worse after the use of the sticks. Rhombhedric crystals, contained in small vegetable lodgments, were identified as anhydrous CaSO4 by X-ray diffraction. No antibacterial activity towards some oral streptococci was noted in various misswak extracts. The present study was carried out to determine the inorganic constituents of salvadora sticks by using the spectroscopic techniques.

1. JR absorption 2. X-ray diffraction 3. Atomic emission



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E7 FTIR, UV-vis Absorption spectra and the Optical Parameters of 4-tricyanovinyl-N, N-diethylaniline

thin Films

M.M. El-Nahassa,*, H.M. Zeyadab, K.F. Abd-El-Rahmana, A.A.M. Faraga, A.A.A. Darwisha

aPhysics Department, Faculty of Education, Ain Shams University, Rorxy Square 11757, Cairo, Egypt.

b Physics Department, Faculty of Science at New Damietta, New Damietta 34517, Egypt.

Thin films of 4-tricyanovinyl-N,N-diethylaniline (TCVA) were prepared for the first time using thermal evaporation technique. The molecular structure and electronic transitions of TCVA films were investigated by FTIR and UV-vis spectra. FTIR spectra were recorded in the spectral range 400-40000 cm-1. The observed vibrational wavenumbers in FTIR spectra were analysed and assigned to different normal modes of the molecule. UV-vis electronic absorption spectral measurements of TCVA films were made in the 200–1200 nm region and the spectra obtained were analysed to obtain the electronic transitions and optical band gap (Eg). Other important optical parameters such as molar extinction coefficient (εmolar), the oscillator strength (f), and the electric dipole strength (q) were also reported.



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E8 Simulation and Modeling of

Single-Electron Transistors (SETs): A Review

M. Y. Ismail, Student Member, IEEE and R. A. AbdelRassoul, Senior Member, IEEE

Arab Academy for Science and Technology, Alexandria, Egypt [email protected]

An extensive review of the simulation and modeling of single-electron transistors (SETs) is presented, starting with the basic physics of single-electron devices, explaining the orthodox theory, Coulomb blockade of tunneling phenomenon in SET devices, and the Hadley derivation for electrostatic energy of single-electron circuit for calculating the electrostatic energy in a single-electron circuit. The Master Equation (ME) algorithm, where single-electron systems involve tunneling of many electrons, and employing a master equation approach in the charge transport analysis across a uniform multiple-tunnel junction (MTJ) memory trap. The Monte Carlo (MC) modeling, based on analyzing the stochastic process of tunneling for single tunnel junction, used by Wasshuber to calculate the current as a function of all calculated tunnel events. The SIMON algorithm introduced by Wasshuber and Kosina for the simulation of devices and circuits consisting of tunnel junctions, capacitors, constant voltage sources, piecewise linear voltage sources and voltage controlled voltage sources, and incorporating the co-tunneling, is then presented. SPICE MODELING, where two assumptions are implicitly used: that once the parameter of the isolated transistor is determined from the device simulator or other modeling tools, it can be used in the whole circuit, and that the characteristics of the device are affected by neighboring transistors only through the changes of the terminal voltages of those transistors. However, in the case of the circuits with SET’s, the terminal currents of the SET are determined from the average charge state of the Coulomb island of the SET. When several SET’s are connected, the charge state of the Coulomb island of one SET is strongly affected by the charge states of neighboring islands of other SET’s. All of the existing single -electron circuit simulators MOSES, SIMON and KOSEC (Korea Single Electron Circuit simulator have procedures to take into account the interaction between neighboring Coulomb islands, usually based on the Monte Carlo technique and require a huge amount of computation time.



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E9 Optical Characterization of Amorphous

Gex Sb40-xSe60 Thin Films

I. K. El Zawawi and A. M. Farid*

Solid State Physics Dep., Physics Division, National Research Center, 12622, Dokki, Cairo Egypt.

* Physics Dep., Faculty of Education, Ain Shams University, Roxy, Cairo, Egypt.

Email: [email protected]

Thin Films of GexSb40-xSe60, where x = (0 – 30) were prepared by

thermal evaporation technique at 300K. The X-ray diffraction patterns showed that all investigated samples exhibit amorphous structure. The optical transmission and reflection spectra were measured in the range UV-VIS-NIR up to 2.5 µm. The optical absorption coefficient spectra were studied for deposited samples. It`1 was observed that the optical absorption edge shifts to higher energy range as the germanium content x increases in the film. The optical band gap Eg increases as the Ge content increases. The energy gap E04 and the average gap Eav were discussed in relation to optical band gap and the chemical composition. The refractive index as function of wavelength was studied and the real refractive index of deposited thin films shows a variation with the germanium content x.



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E10 Characteristics of a Global Solar Radiation Monitor

Utilizing Solar Cells

*A.Ibrahim and T.I.Elsobkey

Physics departmnet, Faculty of science, Tanta University, Egypt e.mail: [email protected]

This paper examined the characteristics of solar cells from the standpoint of developing a global solar radiatin monitor. this study was performed using a simplified test monitor(STM) manufactured from a monocrystalline P-type Czochralski (Cz) silicon solar cell of the construction n+pp++Passivated Emitted Solar Cells (PESC) coupled to a Fluke -73 digital multimeter. The induced short-ciruit current density Jsc (photogenerated current density) was examined during a complete test daylight from 7 AM to 7 PM. Subsequently, the test monitor was used for checking the accuarcy of the transfer operations of solar radiation. The results obtained by the test monitor utilizing solar cells were better than expected : (a) It is very simple in construction, and (b) it exhibits a good response to all solar radiation variations, and (c) it works without an electric power supply.



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E11 Investigation of Scaling Methods and Fitting of

Dyre’s Macroscopic Model with Some Experimental Data of Polypyrrole Samples

A. S. Seoud, S. A. Saafan*, and R.E. El Shater.

Physics Department, Faculty of Science, Tanta University, Tanta, Egypt.

Master curves of some experimental data of A.C. conductivity and dielectric permittivity of polypyrrole samples have been produced by using different scaling parameters. Fitting equations of those master curves have been obtained. The validity of the super master curve of the dielectric loss has been proved by fitting with the equations based upon the definition of the concerned functions and the expected values of some variables in different regions of the frequency range. Moreover, the fitting of the investigated data with Dyre’s macroscopic model by using its two end equation approximations (PPA and EMA) are quite satisfactory in the expected frequency regions.



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E12 Microwave Permittivity of Solid Ceramics

Calculated by Mixture Equations

Thoria A. Baeraky

Faculty of Science, Physics Department, King Abdulaziz University, Jeddah, Saudi Arabia.


Microwave measurements the dielectric properties of two kinds of ceramic materials; alumina Al2O3 and zirconia stabilized with magnesia ZrO2/MgO, in both solid and powder forms, are made using the cavity perturbation technique, working at certain frequency values of 615 MHz, 1412 MHz, 2214 MHz, 3017 MHz, and 3820 MHz. The permittivities of the powder ceramics of both materials are measured over a range of densities. The permittivities of the solid ceramics are measured for two solid rods of 5mm in diameters. The solid permittivities of the powder ceramics are calculated by the mixture equations, complex Refractive index and Landau & Lifshitz, Looyenga, using the measured permittivities of the powder materials. Comparison between the calculated solid permittivities of the powder ceramics with the measured permittivities of the solid ceramics is the project of this work.



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Session F

Wednesday, Sept., 13, 2006 15:00 – 17:00

Chairman

Prof. N. Ghonaim Prof. M. El-Said



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F1 Optoelectronic Applications of ZnO/ZnMgO Quantum Well Lasers in the Blue and the UV

Spectral Regions

Seoung-Hwan Park*, Doyeol Ahn**, Tae Won Kang and Seung Joo Lee***

*Department of Photonics and Information Enginnering, Catholic

University of Daegu, Kyeongbuk 712-702 **Institute of Quantum Information Processing and Systems, University of

Seoul, Seoul 130-743 ***Quantum-functional Semiconductor Research Center, Dongguk

University, Seoul 100-715 1 Corresponding and presenting author: [email protected]

Recently the wide band-gap wurtzite semiconductors have attracted

much attention due to their potential applications for optoelectronic devices in the blue and the ultraviolet (UV) regions. So far, practical short wavelength light-emitting diodes or laser diodes have been fabricated using GaN-related materials. On the other hand, ZnO and related oxides have been proposed as other wide band-gap semiconductors for short-avelength optoelectronic applications because they have several advantages compared to GaN-related materials. In this talk we investigate the electronic and the optical properties of ZnO/ZnMgO quantum well (QW) lasers numerically by using the non-Markovian gain model with many-body effects. These results are compared with those of GaN/AlGaN QW lasers with spontaneous (SP) and piezoelectric (PZ) polarizations grown on a GaN substrate. The heavy-hole effective mass of the ZnO/ZnMgO QW are shown to be relatively smaller than that of the GaN/AlGaN QW. The heavy-hole effective masses of ZnO/ZnMgO and GaN/AlGaN QWs are 0.89 and 1.48, respectively. The optical gain of the ZnO/ZnMgO QW laser is much larger than that of the GaN/AlGaN QW laser. This is attributed to the fact that the ZnO/ZnMgO QW structure has larger optical matrix elements than the GaN/AlGaN QW structure. These results show that ZnO-based QW lasers are promising candidates for optoelectric applications in the visible and the ultraviolet (UV) regions.



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F2 Studying the Effect of Compositional Change

on the Structural, Optical and Electrical Properties of Spray Pyrolysis Deposited CdxZn(1-x )O

thin film on glass

H. H. Afifi a, M. A. Kalef b, T.A. Abdel-monem b a Physics Department, National Research Center, Tahrir St., Cairo, Egypt

b Nuclear Materials Authority, Maadi P.O.B 530, Cairo, Egypt

Ternary Znx Cd(1-x)O alloy crystalline films have been prepared on glass substrates in the temperature range of 300°C-450°C using spray pyrolysis technique. The structure of these films were studied using both X-ray diffraction and Atomic Force Microscopy. Sudden change in roughness which may be as a consequence of change in surface morphology due to phase change and fraction of a new phase is estimated by phase images taken by Atomic Force Microscopy (AFM). Sheet resistance measurements revealed that conductivity remains nearly constant from x=0 to x=0.25 and then it suffered exponential drop as we increased Zinc atomic percent from x=0.33 to x=1. Optical absorption studies revealed that the value of the energy band gap has changed from 2.6 eV (pure CdO) to 3.3 eV (pure ZnO). Photoluminescence measurements at room temperature revealed that luminescence behavior were observed for films in the range 1>x>0.25.



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F3 Investigation of the Preparation Process and

Composition of the Superconductor Bi1.6Pb0.4Sr2+xCa2+YCu3O10+ä

Mahdi H.Suhail, Matti N. Maqadsi and Samir Adnahn Rahma Al-Taie

Dept. of physics, college of science, univ. of Baghdad

E;mail [email protected]

The aim of the research is to prepare pellets from Bi1.6Pb0.4Sr2+xCa2+y Cu3O10+ä (x=0, 0.1, 0.2; y=0, 0.1, 0.2) superconductor compound by direct synthesizing method (DSM) which retern to solid state reaction. Pellets of Bi1.6Pb0.4Sr2+xCa2+yCu3O10+ä were prepared from Oxides, Carboniets, and Nitrates of starting materials in proportion to their molecular weights. The prepartion conditions were constant (pressing pellets at 5Ton, diameter 13mm, thickness 1.5mm, sintering temperature 860oC, with twice sintering time at 120h and regrinding. The results of x-ray diffraction (XRD) tests for all samples showed that the compound contains two main phases; High-Tc Phase (HTP) and Lwo-Tc Phase (LTP) or more as for the samples that have high ratios of Sr, especially the ratio x=0.2 ; y=0.2. From the electrical properies of all samples, we noticed that the compound have the maximum critical temperature Tc=100K for the ratio x=0.1 and y=0.1, [and it has orthorhmbic structure with domination in crystalline direction for high phase at H(1013)] while Tc=85K for the ratio x=0 and y=0. The increase in the Ca content has positive effect on superconductive properties while the Sr content destroied the superconductivity at x=0.2 and y=0.2, 0.1, 0. We did not obtain the single HTP, thus we used the multi-grinding method for the sample Bi1.6Pb0.4Sr2Ca2Cu3O10+ä with sintering temperature 860oC, and sintering times (100h, 150h, 200h, and 240h) and regrinding for each stage.The results of XRD analyses showed that the compound prepared by multi-grinding has also two phases: HTP and LTP. The oxygen content of this sample was ä=0.44 and critical temp. Tc=100K while for the single grinding [x=0, y=0 which is prepared previously (sintered at 240h with single regrinding in the mid of the operation)] was ä=0.37 and Tc=85K. We did not obtain the single HTP, thus we used different preparation methods for the sample Bi1.6Pb0.4Sr2Ca2Cu3O10+ä. These methods related to solid state



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reaction. The first method is Two-Step Method (TSM), where the compound Bi1.6Pb0.4Sr2Ca2Cu3O10+ä sintered at 860oC for 200h (with twice sintering time at 100h and regrinding). The results of XRD analyses showed that the domination of HTP and also the crystalline direction at H(0016) with low ratios of LTP at L(105) and L(0012). The sample had orthorhmbic structure with c=37.8A. From iodemetric titration tested that ä=0.4 and from electrical properties, we found that Tc=105K. The second method is Multi-Step Method (MSM) where the compound Bi1.6Pb0.4Sr2Ca2Cu3O10+ä prepered at sintering temperature of 860oC for 100h with twice sintering time at 50h and regrinding. The results of XRD analyses showed that the compound is single HTP, its lattice constant is c=38A with orthrohmbic structure and growth towards the phase H(002) and H(0014), it has ä=0.55. The results of electrical tests show that the critical temp. is Tc=113K and the transition region width is ÄTc=27K, the matter that indicates the growth of the single high-Tc phase. We used the X-Ray Floursent (XRF) analyses to test the proportions of the elements constituting compound. We compared between the preparation methods and the effect of sintering time (more than 150h) on the loss of the elements constituting the compound. We noticed that in the cause when we had no growing in HTP is due to the loss in the main elements (Bi, Cu) during the longer sintering process.MSM was considered the ideal method to the complete growth high-Tc phase.



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F4 The Mobility of Charge Carriers With Position

Dependent Effective Mass In Quantum Film

Aram Kh. Manaselyan*, Albert A. Kirakosyan

Department of Solid State Physics, Yerevan State University, Alex Manoogian 1, Yerevan 375025, Armenia

In last years a subject of especially steadfast attention of theorists and

experimenters became the size quantized systems with parabolic confining potential. In the model of rectangular quantum well a constant value of effective mass is attached to an electron, however in case of parabolic well such approach is equivalent to neglect the position dependence of effective mass in a well, which, a priori, is not obvious and is not justified. In our work the scattering of electrons on charged impurity centers in a quantum film with parabolic confining potential is investigated taking into account the coordinate dependence of the electron effective mass in a film. The mobility is calculated for various distributions of impurity centers (homogeneous distribution in the film, barrier region and the whole space cases). It is shown, that the taking into account of the coordinate dependency brings to mobility decrease.

* e-mail: [email protected]



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F5 Theoretical Investigation of Superconducting State

Parameters of Cu-Zr Metallic Glasses

P. N. Gajjar*, P. H. Suthar and A. R. Jani

*Department of Physics, University School of Sciences, Gujarat University, Ahmedabad 380 009, Gujarat, INDIA

Department of Physics, Sardar Patel University, Vallabh Vidyanagar 388

120, Gujarat, INDIA A well recognized local model potential is employed to investigate the

superconducting state parameters of CuxZr1-x metallic glasses. The electron-phonon coupling strength (λ), Coulomb pseudopotential (µ*), transition temperature (Tc), isotope effect exponent (α) and interaction strength (NoV) of CuxZr1-x are computed for Cu concentrations 0.25 ≤ x ≤ 0.60. The most advanced screening functions due to Ichimaru and Utsumi, Farid et al. and Sarkar et al. have been employed to include exchange and correlation effects in the screened form factor. Instead of Vegard’s law, the pseudo-alloy-atom model is applied successfully in the investigation. The value of λ and Tc show an appreciable dependency on dielectric screening function whereas for µ*, α and NoV a weak dependency is observed. The value of Tc is found to increase with increase of Cu content in CuxZr1-x metallic glasses. It is concluded from the present investigation of λ, α and NoV that CuxZr1-x metallic glasses are weak to intermediate superconductors.



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F6 Electrical Conductivity and Dielectric Relaxation in

Non-crystalline Films of Tungsten Trioxide

M.G. Hutchinsa, O. Abu-Alkhairb, M.M. El-Nahassc,*, K. Abdel-Hadyd

(a) School of Engineering, Oxford Brookes University, England, UK (b) Physics Department, Faculty of Science, King Abdel-Aziz University,

Jeddah, Saudi Arabia (c) Physics Department, Faculty of Education, Ain Shams University, Roxy

Square11757, Cairo, Egypt, (d) Physics Department, Faculty of Science, Minia University, Minia,

Egypt

Amorphous tungsten trioxide (a-WO3) thin films were prepared by

thermal evaporation technique. The electrical conductivity and dielectric properties of the prepared films have been investigated in the frequency range from100 Hz to 100 kHz and in the temperature range 293-393 K. In spite of the absence of the dielectric loss peaks, application of the dielectric modulus formulism gives a simple method for evaluating the activation energy of the dielectric relaxation. The frequency dependence of σ (ω) follows the Jonscher’s universal dynamic law with the relation σ (ω) = σdc + Aωs, where s is the frequency exponent. The conductivity in the direct regime, σdc, is described by the small polaron model. The electrical conductivity and dielectric properties show that Hunt’s model is well adapted to a-WO3 films.



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F7 Description of State of High-Temperature Ceramic

Yba2 Cu3 O7-x Superconductor With Account of Polycrystalline Structure of the Sample.

G.Gamtsemlidze, K. Gamkrelidze1, M. Mirzoeva, G.Shonia.

Department of Physics, Tbilisi State University 3 Chavchavadze Ave., 0128, Tbilisi, Georgia.

It is considered as a polycrystal YBa2Cu3O7-x Superconductor (HTSC) consisting of monocrystals (granules) oriented arbitrarily relative to the external magnetic field. Basing on the modified Bean critical model the analytical expressions for the along-field directed HTSC sample magnetization was obtained within different field ranges. For the description of magnetization hysteresis of HTSC the structure of a sample is taken into account.



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Session G

Wednesday, Sept., 13, 2006 17:30 – 19:30

Chairman

Prof. S. Abdel Hakim Prof. I. A. Ibrahim



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G1 Phenomenological Model for Creep Behavior in

Cu-8.5at.%Al Alloy

M. Abo-Elsoud

Mater. Sci. Lab., Physics Department, Faculty of Science, Beni-Suef University, Egypt.

Corresponding author. E-mail address: [email protected] (M. Abo-Elsoud)

Creep experiments were conducted on Cu-8.5at.% Al alloy in the

intermediate temperature range from 673 to 873K, corresponding to 0.46-0.72 Tm where Tm is the absolute melting temperature. The present analysis reveals the presence of two distinct deformation regions (climb and viscous glide) in the plot of log ε . vs. log σ . The implications of these results on the transition from power-law to exponential creep regime are examined. The results indicated that the rate controlling mechanism for creep is the obstacle-controlled dislocation glide. A phenomenological model is proposed which assumes that cell boundaries with sub-grains act as sources and obstacles to gliding dislocations.



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G2 Effect of Silver Addition on the Creep Parameters

of Sn-7wt%Bi Alloy During Transformation

F. Abd El-Salam, A. M. Abd El-Khalek, R. H. Nada, and A.Fawzy

Physics Department, Faculty of Education, Ain Shams University, Cairo, Egypt

E.mail: [email protected]

The strain-time relations of Sn-7wt%Bi and Sn-7wt%Bi-1wt%Ag alloys

have been obtained under different constant stresses (34.7 - 76.2 MPa) in the temperature range (313-373 K). The results showed that the transient and the steady state creep parameters n, β and εst depend on both the deformation temperature and the applied stress. The temperature dependence of these parameters indicate a transition temperature at 343 K. The Ag free samples are more hard than those with Ag addition. This is explained by precipitation of Bi-atoms which segregate to form a non-coherent cubic -phase Sn-7wt%Bi samples. While, Ag addition prevents precipitation segregate on the grain boundaries. The analysis of the X-ray diffraction patterns and optical micrographs show that, Ag addition increase the Sn crystallite size but decreases Bi crystallite size. The energy activating the steady state creep in the two alloys in the low and high temperature ranges (before and after transformation temperature) were found to be 51.2 ± 1.6 and 88.1 ± 1.4 kJ/mol for Sn-7wt.%Bi alloy and 34.3 ± 1.9 and 57 ± 1.8 kJ/mol for Sn-7wt.%Bi-1wt.%Ag alloy, respectively.



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G3

Dislocation & Defect Densities using positron annihilation Doppler broadening Technique in

wrought alloy (3003&3005)

M.A. Abdel-Rahman, N.A.Kamel, M. Abdel-Rahman , Yahia A. Lotfy and Emad A. Badawi *

Faculty of Science, Physics Dept., El-Minia University-Egypt

P.O. 61519 El-Minia * e-mail : [email protected]

Positron annihilation Doppler broadening spectroscopy (PADPS) is one of the nuclear techniques used in material science. PADPS measurements are used to study the behavior of defect concentration and dislocation density in a set of 3003 and 3005 wrought aluminum alloy. It has been shown that positrons can become trapped at imperfect locations in solids and the S-parameter can be influenced by changes in the concentration of such defects. There is no observing in the S-parameter change values after the saturation of defect concentration. The S-parameter and trapping rates for the samples deformed up to 10 percent. The concentration of defect range vary (from 1.1 x1016 to 2.061x1017) cm-3 and trapping rat range vary from 1 x109 to 1.2x1010 [*] M. A. Abdel-rahman et. al., progress in physics, vol. 3, pp 66-69(2006).



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G4 Study of FeN Coatings by the Methods of

Rutherford and Nuclear Proton Backscattering

Ali Bakouie1, A.M. Borisov2 and E.A. Romanovsky2

1.Mohaghegh ardebili Uiversity, 56199-11367 Ardabil, Iran 2.D.V. Skobeltsyn Insitue of Nuclear Physics, M.V. Lomonosov

Moscow State University, 119992 Moscow, Russia e-mail: [email protected]

The study of a thermo diffusion nitriding of the "Armco"-iron alloy in the ammonia atmosphere at 850 and 9500C, accordingly, was carried out. Nondestructive methods of an element analysis using 2-8 MeV proton nuclear backscattering spectrometry and X-ray structure analysis allowed establishing the relaxation and cyclic effects of nitride layer formation. The reasons of the texture modifications under nitriding are discussed. The possibilities of 2-8 MeV energy proton nuclear backscattering spectrometry for the investigation were studied. The elemental composition and the structure of near-surface layers of nitride were measured.



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G5 An Investigation to Some Physical and Mechanical Properties of Silver–Tin Alloy Manufactured By

Rapid Quenching Method

Tarik Talib Issa*, Talib Kahlil Ibrahim**

* Baghdad University College of science, physics department, Baghdad, Iraq. [email protected]

** Ministry of science and technology, material science department, Baghdad, Iraq. [email protected]

A silver – tin alloy was prepared, by melting at 1000Co, in inert

atmosphere and rapid quenching in ice water. X–ray diffraction technique was used to determine distinctive phases without and with mercury (Amalgam). Discs amalgam specimens were prepared according to the international specification (A.D.A No. 1) to study the compressive strength after one hour of setting and after seven day at 37 Co. The hardness were tested too. The corrosion resistance of amalgams immersed in an aqueous solution of NaCl and in an phosphate (Na2 HPO4 and NaH2PO4) was tested. Compressive strength and hardness value, obtained were equivalent to the international values. The amalgam alloy showed a clear corrosion resistance. The required phases represented in the domination of γ – Ag3 Sn phase, and the disappearing of γ 2 – Sn7 – 8 Hg phase. Which caused corrosion. Finally Al – Mamoon dental teaching center report superior the clinical performance of alloy and certificate given from Iraqi dental association.



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G6 Effect of Machining Parameters on Surface

Roughness in Cnc-Turning of 304- Austenitic Stainless Steel

A. A. Akbar* and G. H. Senussi **

*Department of industrial engineering.Garyounis university,

Benghazi/Libya ** Department of industrial engineering.Garyounis university,

Benghazi/Libya

The present work is concerned with the effect of turning process

parameters (cutting speed, feed rate, and depth of cut) and nose radius of the tool as input variables on the surface roughness (Ra) as response or out put. In the present work, three experiments have been executed; they were used to investigate the surface roughness resulted by tool corner radii of the values: 0.4mm, 0.8mm, and 1.2mm. Response surface methodology (R.S.M) is a technique to determine and present the cause and effect of the relationship between true mean response and input control variables influencing the response as a two or three dimensional hyper surface. In the present work, R.S.M has been used for designing a three factor with five level central composite rotatable factor designs in order to construct statistical models capable of accurate prediction of responses. The results obtained showed that the application of R.S.M can predict the effect of machining parameters on surface roughness. The five level factorial techniques can be employed easily for developing statistical models to predict surface roughness by controllable matching parameters. Results obtained showed that the combined effect of cutting speed at its higher level both feed rate and depth of cut at their lower values using large nose radius can result in better surface roughness.



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G7 Frequency dependence and effect of In on the

characteristics of Al-5 wt.% Zn

F. Abd El-Salam1, L.A.Wahab2, R.H.Nada1*, and H.Y.Zahran1

1 Physics Department, Faculty of Education, Ain Shams University, Cairo, Egypt.

2 National Centre for Radiation Research and Technology, Nasr-City, Cairo, Egypt.

Email:[email protected]

Samples prepared from highly pure Al, Zn and In were homogenized for 50h then swaged into wire of diameter 0.7mm. The samples were solution treated at 773K for 2h then quenched to room temperature, and immediately after quenching, the specimens were aged for 2h at different temperatures. Creep testes were carried out under constant stress of 6.6 MPa, constant shear strain amplitude of 5.16 × 10-4 and low frequency from, 0.0, to 3.9Hz superimposed on the static stress during creep test. The structure variations were traced through the analysis of X-rays diffraction patterns and SEM micrographs. Samples deformed at 383 K, showed irregular behaviour that can be attributed to the coarsening of α and β grains (Zn) associated with the dissolution of Zn and Al which takes place to satisfy the actual equilibrium composition Above 383 K marked increased strain is observed. Both the parameters β and n increased with increasing temperature. Increasing frequency decreased β and increased n due to a certain degree of fatigue hardening. The observed decrease of β and

sε& after the peak values may be attributed to the coarsening of Al-rich phase particles which reduces their inhibiting effect on grain boundary. The higher values of β obtained at higher temperatures, were attributed to the reduced crack initiation life associating the existing large grain size. The high average value of γ (δln β / δln sε& ), 0.77, was explained in view of the so-called, substeady state creep.



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G8 Transformation Characteristics of Al-10wt%Ag

and Al-10wt%Ag-0.2wt%Ti Alloys

A. M. Abd El-Khalek

Department of Physics, Faculty of Education, Ain Shams University, Holiopolis, Roxy, Cairo, Egypt

The effect of structure transformation on the stress-strain characteristics of Al-10wt%Ag and Al-10wt%Ag-0.2wt%Ti alloys has been studied in the temperature range from 523 to 623 K for both quenched and slowly cooled specimens. The coefficient of work hardening, χ=∂σ2/∂ε, the fracture time tf, yield stress, σy and fracture stress, σf, decreased with increasing deformation temperature (T) and exhibited abrupt increase at about 583 K. On the other hand, for each curve the fracture strain, εf, and dislocation slip distance, L, increased with increasing deformation temperature and exhibited minima at about 583 K. The Ti-free samples were generally harder than the ternary samples. The activation energy of the fracture mechanism in both alloys was around 25 ± 0.4 and 53 ± 0.4 kJ/mol before and after transformation respectively. The microstructure of the studied samples was investigated below and above the transformation temperature by transmission electron microscopy (TEM) and X-ray diffraction analysis. E-mail: [email protected]



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G9 Study on Photocatalytic Oxidation of Indigo

Carmine Dye on Mn-Supported TiO2

Reda M. Mohameda , Ibrahim Othman Alib*

, Ibrahim A. Ibrahima

a Central Metallurgical R&D Institute, Department of Nanostructured

Material, Helwan, Cairo, Egypt. bFaculty of Science, Chemistry Department, Al-Azhar University, Nasser

City, Cairo, Egypt. *[email protected]

10 wt. % of manganese, ions in nitrate form was supported on titania prepared by sol–gel and impregnation methods. Specifically, the obtained catalysts were treated thermally at 500ºC and then characterized using XRD, FTIR and N2 adsorption measurements. The electrical conductivity has also been measured by applying Zeta potential technique to attain the effect of Mn supported on TiO2. Analysis of anatase-rutile phase transformation in TiO2 showed increased upon the addition of Mn. These materials were tested for discoloration (adsorption) and mineralization (in the presence of UV irradiation) of indigo carmine (IC) dye. The experimental results show that Mn/TiO2-imp is the highest photocatalytic activity. The influence of pH, catalyst amount and time on the decolorization rate of IC on Mn/TiO2-imp was thoroughly investigated and correlated with ZPC of MnOx species, various exposed species of MnOx and surface properties.



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Session H

Wednesday, Sept., 13, 2006 17:30 – 19:30

Chairman

Prof. M. Semary Prof. Y. Abbas



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H1 Singular Extended States in Quasiperiodic GaAs /AlxGa1-xAs Fibonacci Superlattices

Z. Aziz , S. Bentata and R. Djelti

Faculté des sciences et Sciences de l’ingénieur, Université de

Mostaganem, BP 188, 27000 Algérie

We examine numerically the effect of quasiperiodicity in the nature of the states in Fibonacci semiconductor superlattices by means of the transfer matrix formalism. We are interested in the GaAs/AlxGa1-xAs layers, having identical thickness, where the aluminium concentration x takes, two different values. We have found that each miniband of the periodic superlattice splits in several sub-minibands, that is small minigaps appear. We demonstrate that the origin of these small inner minigaps is due to the loss of long-range quantum coherent of the electrons wave. The corresponding electronic spectrum shows a high fragment. The states having transmission coefficient close to zero in the minibands can be viewed as consisting of singular extended states.

References [1] F. Dominguez-Adame and A. Sanchez, Phys. Rev. Lett. A159 (1991) 153. [2] S. Bentata, B. Ait Saadi and H. Sidiki, Superlatt. Microstruct. 30 (2001) 297. [3] S. Bentata, Superlatt. Microstruct. 37 (2005) 295. [4] J.W. Dong, P. Han, and H.Z. Wang. Chinese Physics Letters, 20 (2003)

1963.



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H2 Characterization of Spray Pyrolysis SnO2 Heat

Mirror System

A. Abd Elmongy, S. H. Mostafa , H. Hashem and A. A. Ramadan

Physics Department, Faculty of Science, Helwan University Spray pyrolysis with special modifications is used for film preparation of

the required coatings. Three series of samples: SnC>2, Al (and Sb) doped SnC>2 films are formed. Different thicknesses besides dopant concentrations are testified. Quality films (how sheet resistance combined with high transmission) are obtained at substrate temperature of 500°c; flow rate lOL/min and substrate to nozzle distance of 45 cm. Structural investigation identified the formation of a single SnC>2 phase with preferred orientation along (110) plane for investigated films. Al-doped films results in some deformation due to the induced internal strain; while Sb-doping increased the crystallinity. Discussion of the changes in structural characteristics is based on the difference in charge as well as ionic radii of both Sn and dopants. Optical characterization proved that the required spectral behaviour for heat mirror can not be achieved by Al-doping; while films doped with Sb are better for heat mirror preparation.



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H3 Charachterization of Electrochromic Vanadium

Pentoxide Thin Films Prepared by Spray Pyrolisis

M. F. Kaid

Phsics Department, Menia University, El Menia, Egypt.

Amorphous and crystalline vanadium pentoxide (V2O5) thin films were grown onto heated glass substrates, using spray pyrolysis technique. Aqueous solution of ammonium meta-vanadium with different oncentrations ranging from 0.1 to 0.5M was used. X-ray diffraction study of c-V2O5 revealed polycrystalline films of orthorhombic structure with a preferred orientation along (001) plane. Voigt analysis of single reflection was used to determine crystallite size and microstrain. The refractive index n and the extinction coefficient k have been computed from the corrected transmittance and reflectance over the spectral range 300 to 2500 nm. Analysis of the absorption coefficient versus photon energy revealed allowed direct transitions with energy gap 2.37 eV. The electrochromic behavior has been investigated using three- electrode cell. Upon sodium insertion, the results showed that the changes in the optical absorption are consistent with the colour changes of the film. On applying the voltage the optical absorption in the wavelength range 500 – 900 nm and the absorption edge shifts towards lower energies. The film colouration showed to be stable over several tens of hours claiming high colouration memory.



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H4 Optical Characterization of Amorphous

Se1-xGexSby Thin Hilms

I. K. El Zawawi and A. Farid*

Solid State Physics Dep., Physics Division, National Research Center, 12622, Dokki, Cairo Egypt.

* Physics Dep., Faculty of Education, Ain Shams University, Cairo, Egypt.

Email: [email protected]

Thin Films of Se1-xGexSby, where x = (0 - 0.40) and y = 0.60 were prepared by thermal evaporation technique at 300K. The X-ray diffraction patterns showed that all investigated samples exhibit amorphous structure. The optical transmission and refection spectra were measured in the range UV-VIS-NIR up to 2.5 µm. The optical absorption coefficient spectra were studied for deposited samples. It was observed that the optical absorption edge shifts to higher energy range as the germanium content x increases in the film. The optical band gap Eg increases as the Ge content increases. The energy gap E04 and the average gap Eav were discussed in relation to optical band gap and the chemical composition. The refractive index as function of wavelength was studied and the real refractive index of deposited thin films shows a variation with the germanium content x.



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H5 Physical Evolution of (As2Se3)3-x(As2Te3)x Systems

S.A. Fayek, M.R. Balboul, K.H. Marzouk

National Center for Radiation Research and technology, P.O.Box 29

Nasr City, Cairo, Egypt. Optical properties and conductivity of glassy (As2Se3)3-x(As2Te3)x were

studied for 0 < x < 3. The films of the above mentioned compound were prepared by thermal evaporation with thickness of the above mentioned compound wear prepared by thermal evaporation with thickness of about 250 nm. The optical absorption is due indirect transition, and the optical band gap (Eopt) increases with the increase of As2Se3. While, the opposite behavior was found with the band tail width of the localized state Ee. This behavior is believed to be associated with cohesive energy (C.E) and average coordination number. The conductivity measurement on the thin films are reported in the temperature range from 280 to 190 K. The conduction occurs in this low temperature range is due to variable range hopping in the band tails of localized states, which is in reasonable agreement with Mott’s condition of variable range hopping conduction. Some parameters such as coordination number (Z), molar volume (Vm) and theoretically glass transition temperature (Tgth) were calculated and discussed in the light of the topological bonding structure, which involves a hierarchy of correlation ranges in short.



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H6 Optical and Electrical Properties of Transparent

Conducting ZnO Films Prepared By Spray Pyrolysis

S. E. Demian

N.R.C. Cairo

Transparent conducting zinc oxide (unintentionally doped) films, have been prepared by spray pyrolysis using air as the carrier gas. The optical and electrical properties of the films are presented and discussed as a function of substrate temperature. The optical properties were studied in the ultraviolet, visible and near infrared regions. The transmittance data was used to determine the optical constants, refractive index n, extinction coefficient k and absorption coefficient. The reflectivity of the films was calculated and found to be very small in the wavelength investigated, showing a tendency to increase in the infrared range, in order to act as a heat reflector.



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H7 Investigation and Structure Studies of

The Chemically Deposited Lead-Sulfide [PbS] Tthin Films

S. M. Salim

National Research Center

Electron Microscope and thin films Department., Physics Division [email protected]

Lead-sulfide (PbS) films have been deposited by chemical deposition method on glass substrate. The deposition of the PbS films was done at room temperature. The composition of the films was determined by chemical analysis. The principle variations have involved changes in the concentrations of the lead nitrate and thiourea solutions used, the temperature of deposition, and the use of surface seeding nuclei as a means of improving the properties of the films. Microstructure characterization were carried out by X-ray diffraction Philips PW 1390, and scanning electron microscopy JOEL-JSM-T20, in order to determine the crystallite size and study the surface morphologies of the as-deposited and heat-treated films. The grain size of the films as observed by SEM is found to increase with increase in thickness and clear change in the film formation due to annealing. It was established by X-ray analysis that PbS films prepared on glass substrates were polycrystalline and the [111] direction was the primary direction. Structural analysis for the powder and thin films were studied by X-ray powder diffraction with the help of very accurate instrument and a group of software programs. The differential scanning calorimeter DSC spectra shows two exothermic peaks. The thermal analysis DSC-50 investigations were carried out in films prepared by chemical deposition of PbS. E-mail: [email protected]



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H8 Enhancement of Thin Film Quality using Spray

Pyrolysis and Chemical Vapor Deposition Techniques.

E.K. Elmaghraby*, H. Kamal** and N. El-Kadry***

* Experimental nuclear physics Dept. NRC, Atomic Energy Authority,

Egypt ** Phsics Department, Menia University, Egypt

*** Physics Department, Faulty of Science, Minia University, Minia, Egypt.

The present manuscript describes the problems facing thin film deposition techniques by means of spray pyrolysis and chemical vapor deposition. The operation and applications of a new device developed to enhance film quality, prepared by these these techniques, are presented. The method and the apparatus are registered in Egyptian Patent Office (EPO) under the number 023360 and title "An apparatus and a technique for depositing the chemical vapor and spray droplets using electrically enhanced aerodynamical control of the carrier gas". The new apparatus has been successfully used to deposit a conducting film of indum-tin xoide. Due to the inproper preparative conditions, the electrical conductivity is limited to 100-2Ohm.°. In comparison with films prepared with a conventional method, the morphology of the grown film proved to be homogeneous and compsed of very fine grains.



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Posters



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P1 Self Assembly and Langmuir-Blodgett Films of

Calix[4]resorcinarene Derivatives as Corrosion Inhibitors

Piotr Prus and Judit Telegdi

Department of Surface Modification and Nanostructures, Surface Chemistry and Catalysis, Chemical Research Center, Hungarian

Academy of Sciences, Pusztaszeri ut. 59-67, H-1025 Budapest, Hungary.

Corrosion of metals cause significant damage and cost a lot. For decreasing this deterioration inhibitors are used, either in dissolved form or in layers. Our work aimed the elaboration of molecular layers against chemical and microbiologically influences corrosion. The layer inhibits in the first case the aggressive ion’s flux, in the other one the microbiological adhesion. Calix[4]resorcinarenes and they derivatives are known as versatile molecules. Core of the calix[4]resorcinarene is build from resorcinol which has antiseptic properties. These molecules also can form stable LB and self assembly films. In our work calix[4]resorcinarene derivatives were used in mono- and multilayer. Different deposition method such as SA and LB can produce different layers with different properties. We use different types of calix[4]resorcinarene which contain two, one or no double bonds in the structure. For biological experiment molecules with chiral substituents were applied. The monomolecular layers at the air/water interface were characterized by isotherms and BAM. LB mono and multi molecular films were analyzed by SFG spectroscopy. Corrosion processes were followed by AFM technique. The results showed that with some of our chemical both the pitting and the general corrosion were inhibited.

This work was supported by Marie Curie RTN “CHEXTAN”



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P2 Equilibrium Adsorption Isstherm and Cortrolled

Release of Antibiotic Drug Chloroamphenical from Poly (2-Vinyl Pyridine/ Acrylic Acid) Hydrogels

Prepared by Gamma Radiation

Nabila A. Maziad, Samia E. Abd El-Aal and Nabil A. El-Kelesh

National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority, Nasr City, P.O.Box 29, Cairo, Egypt, 11371.

High water sorption of 2- vinyl pyridine (2-vp) / acrylic acid (AAc)

hydrogel wear prepared by free radical polymerization in aquace solution of 2-vp with AAc as solube drug sush as chloroamphenicol antibiotic which has resurged on new studies showing its effectivenees against a wide variety of pathogens 2-vp/AAc has been developed for the controlled release can be controlled and achieved for more than ten days. The burst and controlled release can be turned by very in the amount of the ionic monomer (AAc), the irradiation dose of dynamic swelling tests, the effect of relative content of (AAc) on the swelling properties of the hydrogel system was examined. The adsorption of the drug loading. As a result of dynamic swelling tests, the effect of the ionic monomer (AAc), the irradiation dose of prepared hydrogel, pH of relies media and the concentration of drug loading. As a result of dynamic swelling tests, the effect of relative content of (AAc) on the swelling properties of the hydrogel system was examined. The adsorption of the drug onto (2-PV/AAc) hydrogels is studied by equilibrium adsorption isotherm. Study at various pH’s and concentrations were recognized that the absorption of drug increases with increasing (AAc) content. From Freundlish equation of adsorption isotherm, the empirical constant k and n can be evaluated and showed the ability of hydrogel to be loaded by the drug and the affinity by the drug to uptake the hydrogel. FTIR, thermal stability and scanning electron microscope was taken into our consideration. Microbilogical releasing of the drug loaded of discs of hydrogels was studied in nutrant agar media against Staphylococcus auras microorganism.



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P3 Surface Plasmons Resonance Technique for the

Detection of Nicotine in Cigarette Smoke

T. Abdallaha, S. Abdallab, S. Negmb and H. Talaata

aDeparment of Physics, Faculty of Science, Ain Shams University, 62 Abbas Elakkad Nasr City, Cairo 1615 Egypt

bDeparment of Physics, and Mathematics, Faculty of Engineering, Zagazig University (Shoubra), Cairo, Egypt

We have employed the surface plasmon resonance (SPR) as a sensor

technique for the selective detection of nicotine in real time. The SPR was generated via a prism coupler in a Kretschmann configuration where Ag films of thickness 40 to 42.5 + 0.5 nm were evaporated on the base of the prism. The active material for the interaction with nicotine is a thin film of dioctyl phthalate (DOP) with sodium-tetraphenylborate or DOP with nicotine-tetraphenylborate or DOP only deposited on the Ag film. The angular scan for attenuated total refection (ATR) spectra shows a shift of the SPR maximum coupling angle and a broadening of the Lorentzian line shape, due to the interaction of nicotine molecules with the active layer. The observed data shows that the SPR technique is a fast and accurate method for the detection of nicotine in air due to cigarette smoke.



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P4 Structural, Electrical and Magnetic Properties

of La-doped Mn-Zn Ferrite

M.A. Ahmed, E. Ateia, L.M. Salah and A.K.El-Aziz

Physics Department, Faculty of Science, Cairo University, Giza, Egypt

The real part of dielectric constant (ε′), ac conductivity (σ) and Seebeck coefficient was measured for the samples of the general formula Mu1-xZnxRyFe2-

yO4, 0.0<x<1.0 and y=0.1, sintered at 1200oC with heating rate 4oC/min. X-ray analysis confirmed the cubic spinel structure for the investigated samples. The conduction mechanism was explained in view of the hopping conduction process which occurs among the octahedral sites. A strong correlation between the conduction mechanism and the dielectric behavior takes place, where the polarization and the conductivity are of the same origin. Measurements of the thermoelectric power indicated the existence of two types of conduction either n-type or p-typt depending on Zn content. The exchange interaction constant J was calculated It was found that, (J) decreased with increasing Zn content.



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P5 Thermal Induced Phase Transformation in Some

Semiconductor Compounds

L.A. Wahab, M.B. El-Den*, A. Adam**, M.H. Anoar* and R.A. Khadoor*

National Center for Radiation Research &Technology, Cairo, Egypt.

*Faculty of Science, Ain Shams University, Cairo, Egypt. ** Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt.

Corresponding author: [email protected]

Chalcogenide alloys of the GeSe2-xSnx(x = 0, 0.2, 0.4, 0.6, 0.8, 1.0)

system were prepared, and their glass transition temperature, density, microhardness were experimentally determined. By quenching the alloys in ice-water, some of the alloys are completely amorphous, and some are partially crystalline. Glass stability and kinetic resistance to crystallization are shown in terms of enthalpy (∆Hc) and crystallization energy (E). Studies of the crystallization kinetics using non-isothermal single scan technique show that, random nuclei are already present in as-quenched alloys and growth occurred in two dimensions for GeSe2 and three dimensions for ternary alloys. The glass transition temperature (Tg) and Vicker hardness of Ge-Se-Sn composition were less than that of GeSe2 indicating a weakening of the glass structure. X-ray diffraction investigation showed that GeSe2-xSnx system has monoclinic structure. Both the unit cell volume and the grain size were found to increase by the increase of Sn content.



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P6 Preparation and characterization of

CuS Nanotubes

K. Sedeek, A. Adam, L. Foad(a), L. A. Wahab(b)

Physics Department, Faculty of Science (Girls), Al-Azhar University, Cairo, Egypt

(a) Chemistry Department, Faculty of Science, Al-Azhar University, Cairo, Egypt.

(b) National Centre of Radiation Research of Radiation Research and Technology, Cairo Egypt.

Copper sulphide nanotubes have been solvothermally synthesized

through a Cu(acac)2 precursor decomposition and reaction route. Characterisation by X-ray diffraction and infrared spectroscopy were used for sample characterization. Transmission electron microscope (TEM) investigated the morphology of the product. Large quantities of nanotubes with 3-4 µm in diameter and 9-10 mm in length were found in the TEM image.



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P7 ZnO/Si Solar Cell Fabricated by

Spray Pyrolysis Technique

A A Ibrahim and A Ashour

Physics Department, Faculty of Science, Minia University, Minia, Egypt

The ZnO/Si heterojunctions have been prepared by depositing n-ZnO films doped with aluminium on p-Si by spray pyrolysis method. Heterojunction solar cells were fabricated using the configuration Al/ZnO/Si/In. The electrical properties of the heterojunction are investigated by means of current-voltage measurements in the temperature range 295 to 375 K. The cells show the rectifying behaviour characterized by the current – voltage (I – V) measurement under a dark condition, while photoelectric effects have been exhibited under the illumination. As a result, the conversion efficiency of the fabricated cell of about 6.6% was obtained.



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P8 Structural and Electrical Studies on Al1-xMgx with

Different Concentrations of Mg

A. Ashour, E. Badawi and N. Z. El-Sayed

Physics Department, Faculty of Science, Minia University, Minia,, Egypt

Al1-xMgx with different concentrations of Mg was produced by

spectroscopically technique from melting the ingredient in graphite crucibles sealed under vacuum in quartz ampoules. The samples have been characterized by X-ray studies and electrical measurements. A cubic phase of polycrystalline aluminium has been observed. There is no new phases appearing with different concentrations of Mg contents and quenching temperatures. The results show that the crystallinity (Intensity of (200) plane) increases with both of Mg concentration (<4.44 wt %) and quenching temperature (<898 K). The grain size of the obtained phase decreased with increasing the Mg contents. The resistivity is calculated for different concentrations of Mg at room temperature and found increasing with Mg contents. The grain size is found to be pareameter affecting the resistivity than the preferred orientation.



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P9 Experimental and Theoretical Studies on Some

Ferroelectric Properties of [(Pb1-x Sr x) 1-1.5zLa z]TiO3 Ceramics

G.A.Gamal, M.K. Gergs,M.A.Massaud

Physics Department, Faculty of Science(Qena), South Valley

University, Egypt.

Experimental and theoretical studies have been carried out in this paper to reveal the proper concentration of Sr and La - content which provide the samples of [(Pb1-x Sr x) 1-1.5zLa z]Ti03 ceramics with optimum ferroelectric properties and to find an interpretation for the unusual behavior of the Curie Weiss constants. Three types of samples were considered according to the concentration of La-content in this work. The frequency of electric field for dielectric measurements equals to 1 KHz .. From the relation between the dielectric constant and temperature , the samples of first type (z=3 mole % La) exhibited two anomalies values for εmax at x= 20 and 40 mole %Sr. The samples of second type (z= 6 mole %La )showed a similar behavior but the anomalies values for εmax at x= 25 and 35 mole %Sr. The samples of third type (z=9 mole %La) characterized with only one anomaly value for εmax at x= 30 mole %Sr. In this paper we concluded that at constant concentration of Sr-ion (26mo1%)or Pb-ion (60.5mo1%),both values of Curie Weiss constants (C- ,C+) and εmax increase with increasing of La content. This remark is considered as a unique phenomenon for the behavior of Curie Weiss constants (C- ,C+) ,The experimental value of Tc is in agreement with the calculated value on the basis of the binomial distribution function .The interpretation of the behavior of Curie Weiss constants (C- ,C+) for the samples is attributed to the types of unit cells which dominated in structure.



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P10 Structural Characteristics of Two-and

Three-Dimensional Nanoporous Silica Materials

Mohamed A. Sharaf,* A. K. Barakat, and Farid M. Hota

Department of Chemistry, Helwan University, n i-Helwan, Cairo 11795, Egypt


The recent discovery of ordered mesoporous materials has opened prospects for the development of new technologies in catalysis, separation, drug delivery, and nanoscience, owing to their tunable nanopore size, high surface areas, versatile posibilities of surface functionalization, and diversity in composition, structure, and morphology. Of particular interest are mesoporous silicas consisting of interconnected large cage-type pores being organized in a 3D network. For instance, large pore cage-type mesoporous silica designated as SBA-16 synthesised in acidic media EO-PO-EO triblock copolymer and tetraethylorthosilicate (TEOS) as a silica source, consists of spherical cavities of 9-10 nm in diameter arranged in a body-centered-cubic array (with Im3m symmetry), and connected through a mesoporous opening of 2.0 - 2.5 nm. Such types of high interconnected 3D mesostructure pores materials are expected to be superior to hexagonal structures with 1D channels, specially for applications involving selectivity tuned diffusion, immobilization of large molecules, or host-guest interactions within nanostructured materials. Although numerous reports have dealt with the preparation of large pore ordered mesoporous silica, the ability to control synthesis conditions providing efficient tuning of the structure and textural properties is still rather limited, with often an uncertain degree of ordering and phase purity. In this study, we describe a straight forward route of synthesis high ordered mesoporous silica on low HCl concentration regime in aqueous solution allowing facile thermodynamic control of the silica mesophase formation, using different concentrations of F127 and changing the aging temperature during synthesis. Synthesis of mesoporous silica materials has been studied using Pluronic triblock copolymer F127 nonionic amphiphilic triblock copolymer (EO106 PO70 EO106) as high molecular weight structure-directing agent and TEOS as a silica source. The mesostructure of the silica material



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obtained, as determined by transmission electron microscopy (TEM) and nitrogen adsorption–desorption isotherms. Changing the amount of surfactant has affect on the porosity of the material, where increasing the amount of surfactant has affect on the hydrophobic surface curvature of the micelle and correspondingly the particle morphology. The particle morphology has changed from hexagonal to cubic Fm3m symmetry, with different pore sizes. Some samples with the same molar ratio have different unit cell size according to the change in aging temperature. TEM shows cubic and cage structure of pores obtained under the optimal conditions of synthesis. The structural transformation is limited. The results demonstrate that a change in the amount of surfactant has remarkable effect on the porosity of the material, where increasing the amount of surfactant affects the hydrophobic surface curvature of the micelle and correspondingly the particle morphology. The particle morphology has changed from hexagonal to cubic Fm3m symmetry, with defferent pore sizes. Some samples with the same structures have different unit cell size according to the change in aging temperature. TEM shows cubic and cage structure of pores obtained under optimal conditions of synthesis.



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P11 Characterization of the Structure of Nanoporous Silica Materials

Employing Nitrogen Adsorption-Desorption Isotherms

Mohamed A. Sharaf,* Hamdy F. M. Mohamed, Farid M. Hota

Department of Chemistry, Helwan University, Ain Helwan, Cairo 11795, Egypt Department of Physics, El-Minia University, B.O. 61519 El-Minia, Egypt.


Microporous and Mesoporous silica has attracted much attention from scientists recently. These materials possess both adjustable and uniformed pore sizes covering a new range of potential applications in the micro/meso scale. Various morphologies can be achieved for microporous and mesoporous silica using templating methods or the phase transformation approach. These involve order or shape in micro/meso scale. Nitrogen adsorption-desorption isotherm is used to get total surface area of the pores, SBET, CBET value which calculated from BET, average total pore volume, dynamic pore radius, t-plot, insuring the micro or mesoporosity, beside pore size distribution calculations. Moreover, wall thickness of the material can be calculated by studying the unit cell of the structure. Hysteresis of desorption isotherms is also a very good parameter for determination of pore structure. Positron annihilation lifetime (PAL) spectroscopy has proven to be a useful tool in giving pore size. Other techniques used for detecting the structure and morphology of mesoporous silica materials as X-ray diffraction (XRD), Transmission electron microscopy (TEM), and others. Within the scope of free-volume theories, the o-Ps particle is bound inside a pore region. The o-Ps lifetime distribution relates to the pore-size distribution and pore density. The aim of this study is to investigate the formation of mesoporous silica material. Therefore, positron annihilation lifetime (PAL) technique, cationic surfactant Cetyltrimethyl ammonium bromide (CTABr) as structural directing agent or template, and tetraethylorthosilicate (TEOS) as silica source in alkaline medium have been used. Microporous materials have used in many potential applications. The control and understanding of the pore structure and properties at the nanometer to micrometer length scale provides challenging opportunities for material scientists. Full studies of isotherm and BET equation provided data about the pore size, pore volume, wall thickness, and pore size distribution. Positron annihilation lifetime (PAL) spectroscopy had been supported by nitrogen



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adsorption isotherm, TEM, and XRD techniques. Results thus obtained employing the PAL technique and Nitrogen adsorption isotherm were in excellent agreement. The small pore sizes produced suggests that these materials could be promising in catalysis applications. Change of the amount of template used in the same conditions resulted in change the properties of yield. The great similarities between Nitrogen adsorption isotherm data and positron annihilation lifetime PAL results demonstrates that the later method could be used for pore size and pore volume measurements as well.

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Solid State Physics and Materials Science - Eg-MRS