Nanoscience I Introduction and overview - Prujut · PDF fileNanoscience I Introduction and overview Kai Nordlund 19.9.2010. ... e and technology usually are Nano-1 Kai Nordlund, Department

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Nanoscience I Introduction and overview

Kai Nordlund19.9.2010

Faculty of Science

Department of Physics

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Kai Nordlund, Department of Physics, University of Helsinki

Contents

What is nanoscience and technology?

Why the courses Nanoscience I – IV?

Why is nanoscience new?

Background: visions of Feynman and Drexler

Reality nowResearchHistorical and natural nano Industry and markets

- Finland- World

Future: modern visions and time scales

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What is nanoscience?

”Nanoscience deals with the scientific study of objects with sizes in the 1 -- 100 nm range in at least one dimension. The objects are controlled on this size scale either in terms of manufacturing, modification or analysis, and the research includes some aspect of novelty either in terms of material studied, methods used or question asked.”

- Kai Nordlund 2005

Synthesis of more authoritative sources; very inclusive definition

Three crucial aspects:Novelty (~ 1980 – 1990 onwards )Controllability Includes parts of physics, chemistry, engineering, bio- and medical

sciences

Nanotechnology: Related to nanoscience as science and technology usually are

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Alternative definitions

Nanoscience does not have a single unique definition

The original one:

“Nano-technology mainly consists of the processing of separation, consolidation, and deformation of materials by one atom or one molecule”

- Norio Taniguchi 1974 - By current standards clearly too narrow

The ‘most official’ Finnish definition, by the nanoscience workgroup of the Ministry of Education 2006 (non-Finnish-speakers, sorry…):

Tutkimusmenetelmien ja teknologian kehittämistä makro- ja mikromaailmasta poikkeavien nanomittakaavan uusien ilmiöiden ja prosessien tutkimiseksi

Uusien funktionaalisten atomi- ja molekyylitason materiaalien, rakenteiden ja laitteiden karakterisoimista, mallintamista, suunnittelemista ja valmistamista

Uusien nanomittakaavan ilmiöiden ja rakenteiden manipuloimista ja kontrolloimista atomi- ja molekyylitasolla

There is a certain tendency by some scientist to give up the requirement of novelty, but this is problematic:

Without ‘novelty’ suddenly almost all chemistry, biochemistry and materials physics would be nanoscience

Also, does not correspond to common perception that nanoscience is new

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How small is a nanometer?

D ~ 1 nm

Dearth /Dball = Dball /Lfullerene

D ~ 13000 km

D ~ 0.3 m

Let’s remind ourself of how small a nanometer really is

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Why the courses Nanoscience I –

IV?

Nanoscience is clearly interdisciplinary: it includes many branches of science, and the traditional borderlines are often not meaningful any more

In the spring of 2005 a desire to create a truly crossdisciplinary nanoscience teaching was formed within “Helsinki-Nano” and the National Graduate School in Nanosciences (NGS-NANO)Multiple top-level lecturers to ensure best possible expertiseNanoscience is broad: big programme necessary

Original idea:Prof. Dennis Bamford (Viikki), Acad. Prof. Olli Ikkala (Otaniemi)

Other key developers:

Prof. Marjo Yliperttula (Viikki), Doc. Marc Baumann (Meilahti), Doc. Sami Franssila (Otaniemi), Akat. Prof. Olli Ikkala (Otaniemi), Prof. Juhani Keinonen (Kumpula), Prof. Risto Kostiainen (Viikki), Prof. Seppo Meri (Meilahti), Prof. Marja-Liisa Riekkola (Kumpula), Akat.Prof. Risto Nieminen (Otaniemi), Dr. Runar Törnqvist (Otaniemi), Prof. Kai Nordlund (Kumpula)

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Practical issues

Course coordinators 2010-2011: I: [email protected] II: [email protected], III: [email protected]

Course assistant, courses I-II:[email protected]

Nanoscience I: 2 ov

or 3 op (=ECTS credits)

Mon 16-18 room E207 Physicum

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Course contents

Nanoscience I: Why is nano different Introduction for BSc and MSc students

Nanoscience II: Nanomaterials

Nanoscience III: Nanotechniques

http://www.physics.helsinki.fi/courses/s/nanotiede/ Lecture materials: id “nano”, password “science”Videos: id “Nano”, password “Science”

Exam based on lectures and print-out material

- Exam is in the form of a cheat-sheet one: you may bring one A4 single-sided fully handwritten page of notes with you. Note: only 1 A4 and only handwritten.

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Literature

Nanoscience does not yet have well-established standard books (like say “Ashcroft-Mermin” in solid state physics or “Atkins” in physical chemistry)

Best overview textbooks we know of:

Gabor L. Hornyak, H.F. Tibbals, Joydeep Dutta, Anil Rao, Introduction to Nanoscience

(CRC, USA, 2008), ISBN-13: 978-1420048056, £38.94 on 19.9.2010

Charles P. Poole, Frank. J. Owens, Introduction to nanotechnology (John Wiley & sons, Hoboken, New Jersey, USA, 2003) ISBN 0-471-07935-9. £71.73

amazon.co.uk 19.9.2010

Good intro to soft matter nanoscience:

C. Niemeyer, C. Mirkin (eds): Nanobiotechnology (Wiley-VCH Verlag, Weinheim, Germany, 2004), ISBN 3-527-30658-7

- Copies of critical sections will be provided for printout

Really easy-to-read introduction, cheap, but of course not deep:

Nanotechnology for dummies (R. D. Booker, E. Boysen, Wiley 2005)

Numerous encyclopedias already exist, but are expensive

And often not well edited: coherence and some articles may be poor

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So why is nano new ?

The nano- (meso-) scale has of course been known to exist ever since the size of atoms was determined about 100 years ago

But after that science was pretty much divided into two parts:Atomic physics focused on atoms

- Nuclear and particles physics kept going downwards in size

Materials physics, chemistry and metallurgy focused on the properties of continuum matter

- Molecules and colloids were of course studied, but the primary interest was their macroscopic average properties

The nanoscale, properties of individual nanoobjects when they differ from bulk, was left in between, but most people were not really interested in them

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Why is nano new?

An excellent example on that nano was not of interest to many is the discovery history of carbon nanotubes

These are pretty much the prototype material for nanoscience. Often the credit to finding them is given to Sumio Ijima who described them in 1991.

But but:Russian scientists probably made tubes in 1952

R. Bacon, National Carbon Comp., Parma, Ohio

probably produced them in 1960.

M. Endo, Japani, produced and described them

in 1977, and published it in J. Non-Cryst. Solids

P. Wiles, University of Canterbury, New Zealand

produced and described them in 1979

But nobody cared: time was not ripe for ‘nano’

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Why

is nano different?

Example 1:

atom ball

What fraction of atoms are on the surface of a sphere?

We know one atom layer is about t=0.2 nm thick

Volume of surface atoms:

Vsurface = 4 r2 t

Volume of the whole ball:

Vball = 4 r3/3

Ratio, i.e. fraction of surface atoms:

Vsurface / Vball = 3 t / r

Consider different values of r:

Macro ball: r= 1 m => 3 t / r = 6 • 10-10

Micro ball: r= 1 m => 3 t / r = 6 • 10-4

Nano ball: r= 1 nm => 3 t / r = 0.6 !!

On the nanoscale the fraction of surface atoms is enormous!

From surface science we know these behave differently from the bulk => huge effects on material properties!

More on my 3rd lecture

0.2 nm

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Why

is nano

different?

Example 1:

implications...

Since the surface area ratio is very large, a very small amount of matter is enough to give a huge surface area Important in any kind of application where surfaces are utilized: catalysis,

optical effects, etc. etc.

Imagine taking e.g. a 1.7 cm size cube and divide it into 8 24 times => you get 1 nm side cubes with the same surface area as a football field

Repeat 24 times

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Why

is nano different?

Example 2:

Quantum mechanics changes materials properties

If the length scale of an atomic structure is smaller than the characteristic wavelength of electrons, the electron may be ”confined” in 1, 2 or 3 dimensions The electron ‘wavelengths’ are typically on the nanometer scaleOne can talk about 2D, 1D and 0D-structures depending on how

many dimensions are in the nanometer scale 2D-nanostructure: thin film / quantum

well, electrons confined in 1 dimension 1D-nanostructure: nanowire / quantum

wire, electrons confined in 2 dimensions 0D-nanostructure: nanoparticle /

nanocluster / quantum dot, electrons confined in all 3 dimensions

[“Quantum corral”, IBM]

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Why

is nano different?

The density of states of electrons is dramatically different when one lowers the number of dimensions: 3D: continuous 2D: steps 0D: only peaks!

In a quantum dot the electron states are quantized just like in atoms

But the advantage is that the size of a quantum dot may be changed!An atom is an atom

More on this on Risto Nieminens lecture

Photoemission from CdSe nanoparticles of different size

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Bottom-up vs. top-down and self- assembly

These are three key concepts in nanoscience

Bottom-upBuilding something from atoms up If done manually by human control,

really slow and inefficientPossible solution: self-assembly (≈self-

organization): atoms find desired positions by themselves by some mechanism in nature

Top-downStart from macroscale and miniaturizePrime example: Si chip technologyWorks: Intel and AMD chips > billion (109)

nanoscale components that all work

Modern nanoscience often combination of the two

[IBM]

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Background: the speech of Feynman

The origin of nanoscience can be traced back to a speech which the Nobel laureate in physics Richard Feynman held in 1959 with the title ”There is plenty of room at the bottom”.

Amazingly, many of the most important ideas in nanoscience which are relevant now can be found already in this talkWhole speech available on course web

page, and easily found in the web (google on Feynman and the title)

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Feynman’s speech: role in science

“I would like to describe a field, in which little has been done, but in which an enormous amount can be done in principle. This field is not quite the same as the others in that it will not tell us much of fundamental physics (in the sense of, ``What are the strange particles?'') but it is more like solid-state physics in the sense that it might tell us much of great interest about the strange phenomena that occur in complex situations. Furthermore, a point that is most important is that it would have an enormous number of technical applications.”

Nanoscience does not answer fundamental questions about why the universe exists etc. It is from atoms up.Well known atom-level quantum physics and chemistry underlies it

all One can nevertheless find science-philosophical aspects in

nanoscience (emergence, complexity etc.)- But that is beyond the scope of this course

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Feynman’s speech: miniaturisation

”Why cannot we write the entire 24 volumes of the Encyclopædia Britannica on the head of a pin? “ Feynman calculated that if one can make atom structures

with the width of 40 atoms, one could write the whole Encyclopædia Britannica on the head of a pin

In 1959 this was clearly impossible Feynman was ridiculed for the notion

Today this could be achieved literally!At least if the pin had an Si head (electron beam lithography)

In practice of course nobody would want to do it: DVD’s or USB-sticks work much better

But the vision of Feynman has essentially been realized

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Feynman’s speech: electronics miniaturisation

“I don't know how to do this on a small scale in a practical way, but I do know that computing machines are very large; they fill rooms. Why can't we make them very small, make them of little wires, little elements---and by little, I mean little. For instance, the wires should be 10 or 100 atoms in diameter, and the circuits should be a few thousand angstroms across. “.

This is literally true in Si technology!

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Feynman’s speech: manipulation of atoms

“But I am not afraid to consider the final question as to whether, ultimately---in the great future---we can arrange the atoms the way we want; the very atoms, all the way down! What would happen if we could arrange the atoms one by one the way we want them (within reason, of course; you can't put them so that they are chemically unstable, for example).

This has been realized, on surfacesBut there is a catch

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Feynman’s speech: connection of physics, chemistry and biosciences

“This fact---that enormous amounts of information can be carried in an exceedingly small space---is, of course, well known to the biologists, and resolves the mystery which existed before we understood all this clearly, of how it could be that, in the tiniest cell, all of the information for the organization of a complex creature such as ourselves can be stored. “ …“The theory of chemical processes today is based on theoretical physics. In this sense, physics supplies the foundation of chemistry. But if the physicists [had a hundred times better electron microscope], they could also dig under the chemists in the problem of chemical analysis. It would be very easy to make an analysis of any complicated chemical substance; all one would have to do would be to look at it and see where the atoms are.”

=> In close-to-atomic level science physics, chemistry and biology get a natural connection.

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Feynman’s speech: bio-

and nanomachines

“Biology is not simply writing information; it is doing something about it.” … “What are the possibilities of small but movable machines?” … “A friend of mine (Albert R. Hibbs) suggests a very interesting possibility for relatively small machines. He says that, although it is a very wild idea, it would be interesting in surgery if you could swallow the surgeon. You put the mechanical surgeon inside the blood vessel and it goes into the heart and ``looks'' around. It finds out which valve is the faulty one and takes a little knife and slices it out.

This is one of the most ambitious visions of nanoscience: nanomachines

of complex and controlled functionality

“Nanosurgeon” concepts popular in science fiction introduced here

Man-made complex nanomachines were utopian in the 1950’s, and they still are

On the other hand, biology has nanomachines which definitely work

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The visions of Drexler

In 1986 K. Eric Drexler took the visioning of nanotechnology even further in his book “Engines of Creation: The Coming Era of Nanotechnology”

Basic ideas same as those of Feynman

He described a world with self-replicating nanomachines which can go into cells and repair cancer

On the other hand he also described nanomachines and nanoweapons ”Gray goo”: self-replicating nanomachines

that eat up everything in their way

This idea even Drexler himself has taken back us unrealistic [afterword of the 1990 edition of the book]

[Picture from web site of Drexler’s Foresight institute]

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Reality now

The visions of Feynman and Drexler have been inspiring, but almost certainly nanoscience would have appeared anyway because of independent developments in science, e.g:Atomic force microscopySilicon technology Fullerenes, atom cluster science

I will now present examples of real nanoscience and technology

The interest into this has been in a steady rise since 1995Unfortunately some is just

relabeling of old science

[Scientific publications in the abstract databases Web of Science (all science) with the word nano- anything in the title, keywords or abstract. The physics part is for a search limited to materials physics and physical chemistry classifications. Data collected by Kai Nordlund 2010]

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Reality now: Building one atom at a time

Can be done on surfaces with atomic force microscopes!

[“Quantum ring”, IBM]

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Reality now: atom level transistors

A nanotube transistor, where electricity is conducted in a single carbon moleculeRealized also in Finland

Some of these can function with single electrons

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Reality now: nanotweezers

C. Lieber, Harvard University

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Reality now: nanomachines

1

In Aarhus University in Denmark a molecule has been fabricated which moves on metal surfaces and picks up atoms one at a timeAtomic harvester

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Reality now: nanomachines

2

Nanorotor

[1939rotor.gif]

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BUT: Nothing new under the sun…

There are already nanostructure-based products in history

In glass manufacturing metal nanoparticles have long been used to modify the color of glasses Exciting optical effects Lycurgys cup from the 3rd century

“Wootz”-steel in the original Damascene swordsNanoparticles gave superior properties

[Verhoeven, Scientific American 284 (2001) 62]

But these did not fulfill the nano criterion “controllable” The processes were not understood, and the

manufacturing technology eventually vanished

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Nano in nature

Biology of course works starting from the nanoscaleBut biology

and biochemistry with the aim to understand how living beings works is not nanoscience by itself

But if biological structures are modified by humans with the aim to achieve new kinds of functionality, this may be nanoscience

Nature can inspire nanoscience “Biomimetics”

Nanoparticles exist in natureNatural aerosol nucleation is

basically similar as that of artificial nanoparticles

Important for pollution, but understanding has only recently been achieved

[Hanna Vehkamäki, UH]

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Nanomachines

in nature

The proof that nanomachines with complex functionality may exist comes from nature, e.g. so called ATP-synthases These are really like a machine

with mobile parts The upper part of the

machine is located in an isolating cell membrane

Above the membrane the proton (or sodium) ion concentration is higher than below, which drives the machine

The machine makes the cells energy source ATP from ADP, or can also run in the reverse

Animation ATPsynthase.mov from course web page (quicktime)

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Modifying natural nanomachines

ATP synthase is fascinating bioscience, but not nanoscience by itself

But one of the most promising approaches for making nanomachines is to artificially modify the components of nature for human use

This has been done for ATP synthase

An actine molecule was added to the end, which the synthase then rotated like a propeller!

Movie 104705a.mov (quicktime)[Sambongi, Science 286 (1999) 1722]

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Reality now: nanomarkets

Nanotechnology is not limited to research!

It already now has a big market

Giving numbers to this is difficult, as it depends on what is counted in

A synthesis by Markku Lämsä (TEKES) from different sources:

Wor

ld m

arke

t of n

anot

ech

(GU

SD)

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Reality now: nanoproducts

There are plentyHere is just a couple of examples:

Cheaper or better mobile phones Combined chips in the phonesNanotubes for heat conductanceCoatings to which fingerprints

do not stick

Textiles and windows into which dirt does not stickNanometer-large molecules, which prevent

dirt from sticking to the surface or make it break up

- Window panes that clean up during rain

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Car exhaust catalysis is one of the biggest and most important products that can be counted as nanotech

Their functionality is based on Pt/Pd/Rh-nanoparticles which break up harmful hydrocarbons, carbon monoxide and nitrogen oxides thanks to surface catalysis

Due to the high prize of the metals, it is completely crucial to have them in nanoparticle form

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in Finland

Also in Finland people have managed to commercialize nanotechnology

Atomic Layer Deposition was invented in FinlandPlanar electroluminescent displaysYear 2006 in Intel chips

Orion DiagnosticaNanoparticles to detect molecules

in the medical industry

Liekki OyActive optical fibersDirect Nanoparticle Deposition

Montreal Sports Oy Icehockey clubs and baseball bats

strengthened with carbon nanotubes- nanotube epoxy from Amroy Oy

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in FinlandFINNAIR

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Future: somewhat realistic visions

My completely personal guess over important nano products which have good odds at being realized within 5-20 years

Don’t take this too seriously, in 10 years you will laugh at me for this!

1. Carbon nanotubes which strengthen materials and make the heat or electrically conductive

Already on the market, but better will come

Will there be materials orders of magnitude stronger than steel??

2. Molecules which can take medical molecules to desired places in the body

Intensive research is ongoing

3. New cheap solar cell materials??

Can something really revolutionary be achieved??- If it is, may have huge effect on world energy production

4. Molecular electronics

Something will certainly come up, but can mainstream Si be beaten?

Si nanowires as key transistor parts very promising

5. Hydrogen storage in nanomaterials???

Could have a dramatic impact on the hydrogen economy

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Future: how about the really wild visions?

It is already clear that nanoscience has and will have an important role in technology which affects our daily life

But how about the really wild visions?

Building one atom at a time in 3D will probably not be realized as in the original vision Fundamental problems and too laborious

The nanomachine concept

as presented

by Drexler as a miniaturization of conventional metals industry will certainly not be realizedMetals behave fundamentally different on the nanoscale

On the other hand nanomachines

based on biology will

certainly be realized at least in the labsBut “upscaling” and controllability of these ??

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Future: the wildest vision

The wildest vision which really would change things, which is seriously researched, is the space elevator Old idea, e.g. Arthur C. ClarkeConventional materials are not strong

enough

But carbon nanotubes are in theory strong enough to make it possibleNASA has a small project on this

No one has found fundamental reasons preventing it

But the practical problems are rather considerable:E.g. a 50 km high tower as the bottom…Estimated time scale 100 years…

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Ethics and risks

Like any new technology, nanoscience may lead to dangerous uses, intentionally or unintentionally

In popular culture, science fiction books inspired by Eric Drexler’s wilder visions have given nanoscience a slightly bad reputation This is unfortunate, as they are largely based on the “gray goo” idea

which even Drexler himself has taken back!

On the other hand, there are real and serious security concerns already now E.g. what are health effects of metal nanoparticles and nanotubes? These are already formally regulated by e.g. the EU chemicals

directives, but there still is pretty little research on safe levels Initial studies seem to indicate some nanoparticles may be harmful,

but not nearly as bad as e.g. asbestosis

Risks should neither be exaggerated nor ignored!

Kaarle Hämeri will talk more about this on the course

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Summary: history of nanotechnology

1950 1960 1970 2010200019901980

Insp

iratio

nD

isco

verie

san

d in

vent

ions

1959: Speech of Feynman

1974: First known definition of term by Norio Taniguchi

1986: “Engines of Creation published by Eric Drexler

1981: Scanning Probe Microscopy

1983: Fullerenes

~ 2000: Aberration- corrected TEM’s

1965 – Miniatyrization of Si integrated circuit processing

1991: Carbon nanotubes

2004: Graphene

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Summary: future of nanotechnology??

2050 220021502100

Targeted drug delivery

The space elevator

Single- molecule Si chips

You??

Nanosurgeons

Cure of all cancers

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Nanoscience I Introduction and overview - Prujut · PDF fileNanoscience I Introduction and overview Kai Nordlund 19.9.2010. ... e and technology usually are Nano-1 Kai Nordlund, Department