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Paul Weiss

Paul Weiss

Paul Weiss is a leading nanoscientist at the Pennsylvania State University. He holds numerous positions, including professor of the Depts. of Physics and Chemistry, Associate Director of the Center for Nanoscale Science, and committee membership on professional organizations relating to physics/chemistry. Weiss has co-authored over 180 research publications and US patents.

Personality

Q: What do you enjoy about your work? A: I love exploring the unknown. I enjoy developing new tools for discovery. I also like to think about where a new result might lead. What are the possible ways that we could use what we find? This could be in enhancing chemistry, in growing atomically precise structures, in controlling biological function, or in tailoring some local chemical, physical or electronic properties. --Interview 31-May-2000 with David Bradley on behalf of The Alchemist [http://chemweb.com/alchem/articles/985883673323.html]

Research

The Weiss Research Group specializes in `gaining atomic-scale understanding and control of materials properties'. Scanning probe microscopy, including atomic force microscopy and scanning tunneling microscopy, is used as primary instrumentation to image/interrogate surfaces with novel and unexpected properties. Secondary instrumentation is used to characterize surfaces on a macroscopic level. Projects are interdisplinary in nature, between the fields of quantum physics, computer science, chemistry, and electrical engineering. The Weiss Group has traditionally focused on self-assembled monolayers as a well-defined environment to test chemical reactivity, single-electron transport mechanisms, and as an improvement to [nanofabrication]] techniques. The group has now diversified to encompass projects that have wide-ranging impact in the field of nanoscience. The Weiss Group, of approximately 30 members, is funded from multiple sponsors with an annual operating budget on the order of one million dollars.

External links

- [http://stm1.chem.psu.edu/ Weiss Research Group Website]

Nanoscientist

A nanoscientist is a scientist who specializes in the field of nanoscience or nanotechnology.

Atomic force microscopy

The atomic force microscope (AFM) is a very powerful microscope invented by Binnig, Quate and Gerber in 1986. Besides imaging it is also one of the foremost tools for the manipulation of matter at the nanoscale. The AFM consists of a cantilever with a sharp tip at its end, typically composed of silicon or silicon nitride with tip sizes on the order of nanometers. The tip is brought into close proximity of a sample surface. The Van der Waals force between the tip and the sample leads to a deflection of the cantilever according to Hooke's law, where the spring constant of the cantilever is known. Typically, the deflection is measured using a laser spot reflected from the top of the cantilever into an array of photodiodes. However a laser detection system can be expensive and bulky; an alternative method in determining cantilever deflection is by using piezoresistive AFM probes. These probes are fabricated with piezoresistive elements that act as a strain gage. Using a Wheatstone bridge, strain in the AFM probe due to deflection can be measured, but this method is not as sensitive as the laser deflection method. If the tip were scanned at constant height, there would be a risk that the tip would collide with the surface, causing damage. Hence, in most cases a feedback mechanism is employed to adjust the tip-to-sample distance to keep the force between the tip and the sample constant. Generally, the sample is mounted on a piezoelectric tube, which can move the sample in the z direction for maintaining a constant force, and the x and y directions for scanning the sample. The resulting map of s(x,y) represents the topography of the sample. Over the years several modes of operation have been developed for the AFM. The primary modes of operation are contact mode, non-contact mode, and dynamic contact mode. In the contact mode operation, the force between the tip and the surface is kept constant during scanning by maintaining a constant deflection. In the non-contact mode, the cantilever is externally oscillated at or close to its resonance frequency. The oscillation gets modified by the tip-sample interaction forces; these changes in oscillation with respect to the external reference oscillation provide information about the sample's characteristics. Because most samples develop a liquid meniscus layer, keeping the probe tip close enough to the sample for these inter-atomic forces to become detectable while preventing the tip from sticking to the surface presents a major hurdle for non-contact mode in ambient conditions. Dynamic contact mode was developed to bypass this problem (Zhong et al). In dynamic contact mode, the cantilever is oscillated such that it comes in contact with the sample with each cycle, and then enough force is applied to detach the tip from the sample. Schemes for non-contact and dynamic contact mode operation include frequency modulation and the more common amplitude modulation. In frequency modulation, changes in the oscillation frequency provide information about a sample's characteristics. In amplitude modulation (better known as intermittent contact or tapping mode), changes in the oscillation amplitude yield topographic information about the sample. Additionally, changes in the phase of oscillation under tapping mode can be used to discriminate between different types of materials on the surface. The AFM has several advantages over the electron microscope. Unlike the electron microscope which provides a two-dimensional projection or a two-dimensional image of a sample, the AFM provides a true three-dimensional surface profile. Additionally, samples viewed by an AFM do not require any special treatment that would actually destroy the sample and prevent its reuse. While an electron microscope needs an expensive vacuum environment for proper operation, most AFM modes can work perfectly well in an ambient or even liquid environment. This makes it an excellent tool for studying live biological samples. The main disadvantage that the AFM has compared to the scanning electron microscope (SEM) is the image size. The SEM can show an area on the order of millimetres by millimetres and a depth of field on the order of millimetres. The AFM can only show a maximum height on the order of nanometres and a maximum area of around 100 by 100 micrometres. Additionally, the AFM cannot scan images as fast as an SEM. It may take several minutes for a typical region to be scanned with the AFM, however an SEM is capable of scanning at near real-time (although at relatively low quality). See also: scanning tunneling microscope, scanning probe microscopy, scanning voltage microscopy Category:Nanotechnology Category:Microscopes

References

- Q. Zhong, D. Innis, K. Kjoller, V.B. Elings, Surf. Sci. Lett. 290, L688 (1993). ja:原子間力顕微鏡

Self-assembled monolayers

Self assembled monolayers are surfaces consisting of a single layer of molecules on a substrate. Rather than having to use a technique such as chemical vapor deposition or molecular beam epitaxy to add molecules to a surface (often with poor control over the thickness of the molecular layer), self assembled monolayers can be prepared simply by adding a solution of the desired molecule onto the substrate surface and washing off the excess. A common example is an alkane thiol on gold. Sulfur has particular affinity for gold and an alkane with a thiol head group will stick to the gold surface with the alkane tail pointing away from the substrate. Category:Nanotechnology Category:Thin films

Nanoscience

set produced using MEMS, the precursor to nanotechnology. Courtesy Sandia National Laboratories, SUMMiTTM Technologies, www.mems.sandia.gov]] Nanotechnology comprises technological developments on the nanometer scale, usually 0.1 to 100 nm. (One nanometer equals one thousandth of a micrometre or one millionth of a millimetre.) The term has sometimes been applied to microscopic technology. This article discusses nanotechnology, nanoscience, and molecular nanotechnology.

Introduction

Definition

Nanotechnology is any technology which exploits phenomena and structures that can only occur at the nanometer scale, which is the scale of single atoms and small molecules. The United States' National Nanotechnology Initiative [http://www.nano.gov/html/facts/whatIsNano.html website] defines it as follows: "Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications." Such phenomena include quantum confinement--which can result in different electromagnetic and optical properties of a material between nanoparticles and the bulk material, the Gibbs-Thomson effect--which is the lowering of the melting point of a material when it is nanometers in size, and such structures including carbon nanotubes. Nanoscience and nanotechnology are an extension of the field of materials science, and materials science departments at universities around the world in conjunction with physics, mechanical engineering, bioengineering, and chemical engineering departments are leading the breakthroughs in nanotechnology. The related term nanoscience is used to describe the interdisciplinary fields of science devoted to the study of nanoscale phenomena employed in nanotechnology. This is the world of atoms, molecules, macromolecules, quantum dots, and macromolecular assemblies, and is dominated by surface effects such as Van der Waals force attraction, hydrogen bonding, electronic charge, ionic bonding, covalent bonding, hydrophobicity, hydrophilicity, and quantum mechanical tunneling, to the virtual exclusion of macro-scale effects such as turbulence and inertia. For example, the vastly increased ratio of surface area to volume opens new possibilities in surface-based science, such as catalysis.

History of Use

The first mention of some of the distinguishing concepts in nanotechnology (but predating use of that name) was in "There's Plenty of Room at the Bottom", a talk given by Richard Feynman at an American Physical Society meeting Caltech on December 29, 1959. Feynman described a process by which the ability to manipulate individual atoms and molecules might be developed, using one set of precise tools to build and operate another proportionally smaller set, so on down to the needed scale. In the course of this, he noted, scaling issues would arise from the changing magnitude of various physical phenomena: gravity would become less important, surface tension and Van der Waals attraction would become more important, etc. This basic idea appears feasible, and exponential assembly enhances it with parallelism to produce a useful quantity of end products. The term "nanotechnology" was defined by Tokyo Science University professor Norio Taniguchi in a 1974 paper (N. Taniguchi, "On the Basic Concept of 'Nano-Technology'," Proc. Intl. Conf. Prod. Eng. Tokyo, Part II, Japan Society of Precision Engineering, 1974.) as follows: "'Nano-technology' mainly consists of the processing of, separation, consolidation, and deformation of materials by one atom or one molecule." In the 1980s the basic idea of this definition was explored in much more depth by Dr. Eric Drexler, who promoted the technological significance of nano-scale phenomena and devices through speeches and the books Engines of Creation: The Coming Era of Nanotechnology and Nanosystems: Molecular Machinery, Manufacturing, and Computation, (ISBN 0-471-57518-6), and so the term acquired its current sense. More broadly, nanotechnology includes the many techniques used to create structures at a size scale below 100 nm, including those used for fabrication of nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. It should be noted, however, that all of these techniques preceeded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology or which were results of nanotechnology research. The term nanotechnology is sometimes conflated with the more specific molecular nanotechnology (also known as "MNT"), a proposed form of advanced nanotechnology based on [http://www.e-drexler.com/ productive nanosystems]. Molecular nanotechnology would fabricate precise structures using mechanosynthesis to perform [http://wise-nano.org/ molecular manufacturing]. Molecular nanotechnology, though not yet extant, is expected to have a [http://www.crnano.org/overview.htm great impact] on society if realized. In August 2005, a [http://www.crnano.org/CTF.htm task force] consisting of 50+ international experts from various fields was organized by the Center for Responsible Nanotechnology to study the societal implications of molecular nanotechnology. Technologies currently branded with the term 'nano' are little related to and fall far short of the most ambitious and transformative technological goals of the sort in molecular manufacturing proposals, but the term still connotes such ideas. Thus there may be a danger that a nano bubble will form from the use of the term by scientists and entrepreneurs to garner funding, regardless of (and perhaps despite a lack of) interest in the transformative possibilities of more ambitious and far-sighted work. The diversion of support based on the promises of proposals like molecular manufacturing to more mundane projects also risks creating a perhaps unjustifiedly cynical impression of the most ambitious goals: an investor intrigued by molecular manufacturing who invests in 'nano' only to find typical materials science advances result might conclude that the whole idea is hype, unable to appreciate the bait-and-switch made possible by the vagueness of the term. On the other hand, some have argued that the publicity and competence in related areas generated by supporting such 'soft nano' projects is valuable, even if indirect, progress towards nanotechnology's most ambitious goals.

New materials, devices, technologies

As science becomes more sophisticated it naturally enters the realm of what is arbitrarily labeled nanotechnology. Nanotechnology is based on the fact that the properties of materials become markedly different when their size approaches that of a few hundreds or tens of atoms. Nanoparticles (nanometer sized clusters of atoms), for example, have proved useful in catalysis. A material that is catalytically inactive on the macroscale can behave as a very efficient catalyst when in the form of nanoparticles. For this and other reasons, if nanobots are ever created they will not simply be scaled down versions of contemporary robots (an image popularised by Eric Drexler). The different physics at these scales means that man-made nanodevices will probably bear much stronger resemblance to nature's nanodevices: made from proteins, DNA and membranes, much like viruses. This idea is explored by Richard A. L. Jones in his book Soft Machines: Nanotechnology and Life (ISBN 0-19-852855-8). One fundamental characteristic of nanotechnology is that nanodevices self-assemble. That is, they build themselves from the bottom up. Scanning probe microscopy is an important technique both for characterization and synthesis of nanomaterials. Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. Atoms can be moved around on a surface with scanning probe microscopy techniques, but it is cumbersome, expensive and very time-consuming, and for these reasons it is quite simply not feasible to construct nanoscaled devices atom by atom. You don't want to assemble a billion transistors into a microchip by taking an hour to place each transistor, but these techniques can be used for things like helping to guide self-assembling systems. One of the problems facing nanotechnology is how to assemble atoms and molecules into smart materials and working devices. Supramolecular chemistry is here a very important tool. Supramolecular chemistry is the chemistry beyond the molecule, and molecules are being designed to self-assemble into larger structures. In this case, biology is a place to find inspiration: cells and their pieces are made from self-assembling biopolymers such as proteins and protein complexes. One of the things being explored is synthesis of organic molecules by adding them to the ends of complementary DNA strands such as ----A and ----B, with molecules A and B attached to the end; when these are put together, the complementary DNA strands hydrogen bonds into a double helix,

AB, and the DNA molecule can be removed to isolate the product AB. Natural or man-made particles or artifacts often have qualities and capabilities quite different from their macroscopic counterparts. Gold, for example, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. "Nanosize" powder particles (a few nanometres in diameter, also called nano-particles) are potentially important in ceramics, powder metallurgy, the achievement of uniform nanoporosity, and similar applications. The strong tendency of small particles to form clumps ("agglomerates") is a serious technological problem that impedes such applications. However, a few dispersants such as ammonium citrate (aqueous) and imidazoline or oleyl alcohol (nonaqueous) are promising additives for deagglomeration. (Those materials are discussed in "Organic Additives And Ceramic Processing," by D. J. Shanefield, Kluwer Academic Publ., Boston.) In October 2004, researchers at the University of Manchester succeeded in forming a small piece of material only 1 atom thick called graphene.[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15499015] Robert Freitas has suggested that graphene might be used as a deposition surface for a diamondoid mechanosynthesis tool.[http://www.molecularassembler.com/Papers/PathDiamMolMfg.htm] As of August 23 2004, Stanford University has been able to construct a transistor from single-walled carbon nanotubes and organic molecules. These single-walled carbon nanotubes are basically a rolled up sheet of carbon atoms. They have accomplished creating this transistor making it two nanometers wide and able to maintain current three nanometers in length. To create this transistor they cut metallic nanotubes in order to form electrodes, and afterwards placed one or two organic materials to form a semiconducting channel between the electrodes. It is projected that this new achievement will be available in different applications in two to five years. [http://news.com.com/Barrett+No+end+in+sight+for+Moores+Law/2100-1006_3-5594779.html News.com] reported on March 1st 2005 that Intel is preparing to introduce processors with features measuring 65 nanometers. The company’s current engineers believe that 5 nanometer processes are actually proving themselves to be more and more feasible. The company showed pictures of these transistor prototypes measuring 65, 45, 32, and 22 nanometers. However, the company spoke about how their expectations for the future are for new processors featuring 15,10, 7, and 5 nanometers. Currently the prototypes use CMOS (complementary metal-oxide semiconductors); however, according to Intel smaller scales will rely on quantum dots, polymer layers, and nanotube technology. [http://www.PhysOrg.com PhysOrg.com] writes about the use of plasmons in the world. Plasmons are waves of electrons traveling along the surface of metals. They have the same frequency and electromagnetic field as light; however, the sub-wavelength size allows them to use less space. These plasmons act like light waves in glass on metal, allowing engineers to use any of the same tricks such as multiplexing, or sending multiple waves. With the use of plasmons information can be transferred through chips at an incredible speed; however, these plasmons do have drawbacks. For instance, the distance plasmons travel before dying out depends on the metal, and even currently they can travel several millimeters, while chips are typically about a centimeter across from each other. In addition, the best metal currently available for plasmons to travel farther is aluminum. However, most industries that manufacture chips use copper over aluminum since it is a better electrical conductor. Furthermore, the issue of heat will have to be looked upon. The use of plasmons will definitely generate heat but the amount is currently unknown. The further developments in the field of nanotechnology focuses on the oscillation of a nanomachine for telecommunication. The article states that in Boston an antenna-like sliver of silicon one-tenth the width of a human hair oscillated in a lab in a Boston University basement. This team led by Professor Pritiraj Mohanty developed the sliver of silicon. Since the technology functions at the speeds of gigahertz this could help make communication devices smaller and exchange information at gigahertz speeds. This nanomachine is comprised of 50 billion atoms and is able to oscillate at 1.49 billion times per second. The antenna moves over a distance of one-tenth of a picometer.

Advanced nanotechnology

Advanced nanotechnology, sometimes called molecular manufacturing, is a term given to the concept of engineered nanosystems (nanoscale machines) operating on the molecular scale. By the countless examples found in biology it is currently known that billions of years of evolutionary feedback can produce sophisticated, stochastically optimized biological machines, and it is hoped that developments in nanotechnology will make possible their construction by some shorter means, perhaps using biomimetic principles. However, K Eric Drexler and [http://www.crnano.org/developing.htm other researchers] have proposed that advanced nanotechnology, although perhaps initially implemented by biomimetic means, ultimately could be based on mechanical engineering principles. Determining a set of pathways for the development of molecular nanotechnology is now an objective of a broadly based technology roadmap project [http://physorg.com/news4656.html] led by Battelle (the manager of several U.S. National Laboratories) and the Foresight Institute. That roadmap should be completed by late 2006. In August 2005, a [http://www.crnano.org/CTF.htm task force] consisting of 50+ international experts from various fields was organized by the Center for Responsible Nanotechnology to study the societal implications of advanced nanotechnology.

Interdisciplinary ensemble

A definitive feature of nanotechnology is that it constitutes an interdisciplinary ensemble of several fields of the natural sciences that are, in and of themselves, actually highly specialized. Thus, physics plays an important role—alone in the construction of the microscope used to investigate such phenomena but above all in the laws of quantum mechanics. Achieving a desired material structure and certain configurations of atoms brings the field of chemistry into play. In medicine, the specifically targeted deployment of nanoparticles promises to help in the treatment of certain diseases. Here, science has reached a point at which the boundaries separating discrete disciplines become blurred, and it is for precisely this reason that nanotechnology is also referred to as a convergent technology.

Potential risks

Goo

An often cited worst-case scenario is "grey goo", a hypothetical substance into which the surface objects of the earth might be transformed by self-replicating nanobots running amok, a process which has been termed global ecophagy. Defenders point out that smaller objects are more susceptible to damage from radiation and heat (due to greater surface area-to-volume ratios): nanomachines would quickly fail when exposed to harsh climates. This argument depends on the speed of which such nanomachines might be able to reproduce. Recently, [http://www.crnano.org/PR-IOP.htm new analysis] has shown that this "grey goo" danger is less likely than originally thought. K. Eric Drexler considers an accidental "grey goo" scenario extremely unlikely and says so in later editions of Engines of Creation. The "grey goo" scenario begs the Tree Sap Answer: what chances exist that one's car could spontaneously mutate into a wild car, run off-road and live in the forest off tree sap? However, other long-term [http://www.crnano.org/dangers.htm major risks] to society and the environment have been identified. A variant on this is "Green Goo", a scenario in which nanobiotechnology creates a self-replicating nano machine which consumes all organic particles, living or dead, creating a slime -like non-living organic mass ([http://www.etcgroup.org/article.asp?newsid=373 Green Goo: Nanotechnology Comes Alive!] 23 January 2003, Etcgroup.org).

Poison/Toxicity

For the near-term, critics of nanotechnology point to the potential toxicity of new classes of nanosubstances that could adversely affect the stability of cell walls or disturb the immune system when inhaled or digested. Objective risk assessment can profit from the bulk of experience with long-known microscopic materials like carbon soot or asbestos fibres. There is a possibility that nanoparticles in drinking water could be dangerous to humans and/or other animals. Colon cells exposed to nano titanium dioxide particles have been found to decay at a quicker than normal rate. Titanium dioxide nanoparticles are often used in sunscreens, as they appear transparent, compared to natural titanium dioxide particles, which appear white.

External links

Articles

- [http://www.smalltimes.com/document_display.cfm?document_id=7161 MOLECULAR NANOTECHNOLOGY: FULLY LOADED WITH BENEFITS AND RISKS], by Mike Treder, published 2004 in [http://www.wfs.org/futurist.htm The Futurist]
- [http://topics.developmentgateway.org/nanotechnology Nanotechnology for Development]
- [http://www.trnmag.com/Stories/2005/030905/Nanotubes_boost_molecular_devices_Brief_030905.html Stanford University transistors]
- [http://mprc.pku.edu.cn/courses/architecture/spring2005/20nmpressfoils.pdf Intel prototypes]
- [http://news.com.com/Barrett+No+end+in+sight+for+Moores+Law/2100-1006_3-5594779.html News.com, March 1 2005 "Barrett: No end in sight for Moore's Law"]
- [http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html Drexler and Smalley make the case for and against 'molecular assemblers']
- Margaret E. Kosal, [http://www.thebulletin.org/article.php?art_ofn=so04kosal "Is Small Scary?"], Bulletin of the Atomic Scientists, September/October 2004.
- [http://www.isracast.com/tech_news/091205_tech.htm Nano armor - Protecting the soldiers of tomorrow] - An article from IsraCast

Journals and News

- [http://CRNano.typepad.com Responsible Nanotechnology] - daily weblog
- [http://www.nanotechnology.com/blogs/blognano Darrell Brookstein of nanotechnology.com] - daily weblog
- [http://www.nanotechnology.com/blogs/steveedwards Steve Edwards of nanotechnology.com] - daily weblog
- [http://www.nanobound.com Nanobound Weblog] - daily weblog
- [http://www.azonano.com/Materials.asp?Letter=_ Nanotechnology and Nanomaterials A to Z]
- [http://www.whatsnextnetwork.com/technology/index.php?cat=65 Recent Developments In Nanotechnology]
- [http://www.iop.org/EJ/journal/0957-4484 Nanotechnology], electronic journal since 1990, available on web and CD-ROM.
- [http://pubs.acs.org/journals/nalefd/ Nano Letters], electronic journal published by American Chemical Society.
- [http://aspbs.com/jnn/ Journal of Nanoscience and Nanotechnology]
- [http://www.aspbs.com/ctn/ Journal of Computational and Theoretical Nanoscience]
- [http://nanotechwire.com/ Nanotechnology news and related research]
- [http://www.NTalert.com/ Nanotechnology news links - updated daily]
- [http://nanotech-now.com/ Nanotechnology basics, news, and general information]
- [http://www.smalltimes.com/ Small Times: News about MEMS, Nanotechnology and Microsystems]
- [http://nanotechweb.org nanotechweb.org: nanotechnology news, products, jobs, events and information]

Laboratories

- [http://www.memsnet.org/ The MEMS and Nanotechnology Clearinghouse / The world's most popular portal for Nanotechnology information, jobs, and events]
- [http://www.london-nano.ucl.ac.uk/ The London Centre for Nanotechnology / A research centre jointly set up by University College London and Imperial College London]
- [http://www.cnsi.ucla.edu/ The California NanoSystems Institute]
- [http://www.mems-exchange.org/ The MEMS and Nanotechnology Exchange / A repository of Nanotechnology fabrication information]
- [http://smalley.rice.edu/ The Smalley Group / Carbon Nanotechnology Laboratory]
- [http://cben.rice.edu/ Center for Biological and Environmental Nanotechnology]
- [http://bios.ewi.utwente.nl Bios: The Lab-on-a-Chip Group, Universiteit Twente ]
- [http://www.cnm.utexas.edu/ Center for Nano & Molecular Science & Technology- CNM at UT Austin]
- [http://cnst.rice.edu/ Center for Nanoscale Science and Technology at Rice University]
- [http://biomems.uwaterloo.ca/ Advanced Micro/Nanodevices Lab at the University of Waterloo]
- [http://www.cns.cornell.edu/ Cornell University Center for Nanoscale Systems]
- [http://www.cnf.cornell.edu/ Cornell NanoScale Science & Technology Facility (CNF)]
- [http://www.mesaplus.utwente.nl/ MESA+ Institute for Nanotechnology - Universiteit Twente]
- [http://www.ns.tudelft.nl The Kavli Institute of Nanoscience Delft]
- [http://www.uta.edu/engineering/nano/ NanoFab Research and Teaching Facility at the University of Texas at Arlington]
- [http://nanotech.utdallas.edu/nn/index.asp NanoTech Institute at the University of Texas at Dallas]
- [http://www.macdiarmid.ac.nz/ The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand]

Nanotechnology and Society

- [http://CRNano.org Center for Responsible Nanotechnology]
- [http://www.law.harvard.edu/programs/lwp Labor and Worklife Program at Harvard Law School, Nanotechnology Initiative]
- [http://www.etcgroup.org ETC group] Action group on Erosion, Technology and Concentration
- [http://www.bioethicsanddisability.org/nanotechnology.html Bioethics and Disability] Nanotechnology
- [http://www.nanotechwatch.org NanotechWatch.org] Nanotechnology news: the hype and the reality of this emerging technology

Other

- [http://www.nanotechnology.com/ Nanotechnology.com] News, information, and exclusive articles
- [http://www.nano-map.de Nano-map.de] - Nano-map is a graphical tool for the visualization of the regional distribution of relevant nanotechnology institutions in Germany including major enterprises, SMEs, networks, research centers, university institutes, funding agencies, technology transfer and financing institutions.
- [http://www.nanowerk.com/ Nanowerk] - A free database to research almost 800 nanomaterials from over 50 manufacturers
- [http://www.foresight.org/ Foresight Institute]
- [http://icon.rice.edu/ International Council on Nanotechnology]
- [http://www.MolecularAssembler.com Molecular Assembler website]
- [http://www.nanobuildings.com/ NanoBuildings - Buildings for Advanced Technology Workshops]
- [http://www.nano.gov/ National Nanotechnology Initiative]
- [http://nanoDiamond.info/ NanoDiamond] atomic level design of a very high strength-to-weight ratio material
- [http://www.nanotec2005.com/ Nanotec Congress in Brazil]
- [http://nprl.bham.ac.uk/ UK research]
- [http://www.wise-nano.org Wise-Nano] A Wiki project, initiated by the [http://crnano.org/ Center for Responsible Nanotechnology] and devoted to Molecular Manufacturing
- [http://www.etcgroup.org/article.asp?newsid=375 The Big Down] - The first Civil Society Critique of Nanoscale technologies from [http://www.etcgroup.org ETC Group]
- PNAS supplement: [http://www.pnas.org/content/vol99/suppl_2/ Nanoscience: Underlying Physical Concepts and Phenomena]
- [http://www.nanomedicine.com Medical nanorobotics textbooks online]
- [http://www.zyvex.com/nano/ Nanotechnology by Dr.Ralph Merkle]
- [http://www.nanoindustries.com/ Nanotechnology Industries]
- [http://www.knhproductions.ca/nisnano/ Documentary on Nanotechnology]
- [http://www.human-evolution.org/nano.php Nanotechnology: Is it Real?]
- [http://www.physorg.com/news3415.html Plasmons (Physorg)]
- [http://www.nanocrete.com nanotechnology applied to concrete manufacturing]
- [http://whatsnextnetwork.com/technology/index.php/2005/06/22/nanoparticles_transport_cancer_killing_d Nanotechnology & Cancer Cures]
- [http://www.nanotechnologybasics.com/ Nanotechnology Basics]

Scientists in the Field

Dr. David G. Grier, of New York University, has developed a method of rapidly modulating laser beams via a dynamic spatial light modulator (SLM) in the form of a phase only hologram. (http://www.physics.nyu.edu/grierlab/)robots

References

-
- [http://www.nanotechproject.org/ Project on Emerging Nanotechnologies]
- [http://cben.rice.edu/ Centre for Biological and Environmental Nanotechnology]
- [http://www.nanobusiness.org/ NanoBusiness Alliance] ko:나노 과학 ja:ナノテクノロジー th:นาโนเทคโนโลยี

Nanoscience

Introduction

Definition

History of Use

New materials, devices, technologies

AB, and the DNA molecule can be removed to isolate the product AB. Natural or man-made particles or artifacts often have qualities and capabilities quite different from their macroscopic counterparts. Gold, for example, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. "Nanosize" powder particles (a few nanometres in diameter, also called nano-particles) are potentially important in ceramics, powder metallurgy, the achievement of uniform nanoporosity, and similar applications. The strong tendency of small particles to form clumps ("agglomerates") is a serious technological problem that impedes such applications. However, a few dispersants such as ammonium citrate (aqueous) and imidazoline or oleyl alcohol (nonaqueous) are promising additives for deagglomeration. (Those materials are discussed in "Organic Additives And Ceramic Processing," by D. J. Shanefield, Kluwer Academic Publ., Boston.) In October 2004, researchers at the University of Manchester succeeded in forming a small piece of material only 1 atom thick called graphene.[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15499015] Robert Freitas has suggested that graphene might be used as a deposition surface for a diamondoid mechanosynthesis tool.[http://www.molecularassembler.com/Papers/PathDiamMolMfg.htm] As of August 23 2004, Stanford University has been able to construct a transistor from single-walled carbon nanotubes and organic molecules. These single-walled carbon nanotubes are basically a rolled up sheet of carbon atoms. They have accomplished creating this transistor making it two nanometers wide and able to maintain current three nanometers in length. To create this transistor they cut metallic nanotubes in order to form electrodes, and afterwards placed one or two organic materials to form a semiconducting channel between the electrodes. It is projected that this new achievement will be available in different applications in two to five years. [http://news.com.com/Barrett+No+end+in+sight+for+Moores+Law/2100-1006_3-5594779.html News.com] reported on March 1st 2005 that Intel is preparing to introduce processors with features measuring 65 nanometers. The company’s current engineers believe that 5 nanometer processes are actually proving themselves to be more and more feasible. The company showed pictures of these transistor prototypes measuring 65, 45, 32, and 22 nanometers. However, the company spoke about how their expectations for the future are for new processors featuring 15,10, 7, and 5 nanometers. Currently the prototypes use CMOS (complementary metal-oxide semiconductors); however, according to Intel smaller scales will rely on quantum dots, polymer layers, and nanotube technology. [http://www.PhysOrg.com PhysOrg.com] writes about the use of plasmons in the world. Plasmons are waves of electrons traveling along the surface of metals. They have the same frequency and electromagnetic field as light; however, the sub-wavelength size allows them to use less space. These plasmons act like light waves in glass on metal, allowing engineers to use any of the same tricks such as multiplexing, or sending multiple waves. With the use of plasmons information can be transferred through chips at an incredible speed; however, these plasmons do have drawbacks. For instance, the distance plasmons travel before dying out depends on the metal, and even currently they can travel several millimeters, while chips are typically about a centimeter across from each other. In addition, the best metal currently available for plasmons to travel farther is aluminum. However, most industries that manufacture chips use copper over aluminum since it is a better electrical conductor. Furthermore, the issue of heat will have to be looked upon. The use of plasmons will definitely generate heat but the amount is currently unknown. The further developments in the field of nanotechnology focuses on the oscillation of a nanomachine for telecommunication. The article states that in Boston an antenna-like sliver of silicon one-tenth the width of a human hair oscillated in a lab in a Boston University basement. This team led by Professor Pritiraj Mohanty developed the sliver of silicon. Since the technology functions at the speeds of gigahertz this could help make communication devices smaller and exchange information at gigahertz speeds. This nanomachine is comprised of 50 billion atoms and is able to oscillate at 1.49 billion times per second. The antenna moves over a distance of one-tenth of a picometer.

Advanced nanotechnology

Interdisciplinary ensemble

Potential risks

Goo

Poison/Toxicity

External links

Articles

- [http://www.smalltimes.com/document_display.cfm?document_id=7161 MOLECULAR NANOTECHNOLOGY: FULLY LOADED WITH BENEFITS AND RISKS], by Mike Treder, published 2004 in [http://www.wfs.org/futurist.htm The Futurist]
- [http://topics.developmentgateway.org/nanotechnology Nanotechnology for Development]
- [http://www.trnmag.com/Stories/2005/030905/Nanotubes_boost_molecular_devices_Brief_030905.html Stanford University transistors]
- [http://mprc.pku.edu.cn/courses/architecture/spring2005/20nmpressfoils.pdf Intel prototypes]
- [http://news.com.com/Barrett+No+end+in+sight+for+Moores+Law/2100-1006_3-5594779.html News.com, March 1 2005 "Barrett: No end in sight for Moore's Law"]
- [http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html Drexler and Smalley make the case for and against 'molecular assemblers']
- Margaret E. Kosal, [http://www.thebulletin.org/article.php?art_ofn=so04kosal "Is Small Scary?"], Bulletin of the Atomic Scientists, September/October 2004.
- [http://www.isracast.com/tech_news/091205_tech.htm Nano armor - Protecting the soldiers of tomorrow] - An article from IsraCast

Journals and News

- [http://CRNano.typepad.com Responsible Nanotechnology] - daily weblog
- [http://www.nanotechnology.com/blogs/blognano Darrell Brookstein of nanotechnology.com] - daily weblog
- [http://www.nanotechnology.com/blogs/steveedwards Steve Edwards of nanotechnology.com] - daily weblog
- [http://www.nanobound.com Nanobound Weblog] - daily weblog
- [http://www.azonano.com/Materials.asp?Letter=_ Nanotechnology and Nanomaterials A to Z]
- [http://www.whatsnextnetwork.com/technology/index.php?cat=65 Recent Developments In Nanotechnology]
- [http://www.iop.org/EJ/journal/0957-4484 Nanotechnology], electronic journal since 1990, available on web and CD-ROM.
- [http://pubs.acs.org/journals/nalefd/ Nano Letters], electronic journal published by American Chemical Society.
- [http://aspbs.com/jnn/ Journal of Nanoscience and Nanotechnology]
- [http://www.aspbs.com/ctn/ Journal of Computational and Theoretical Nanoscience]
- [http://nanotechwire.com/ Nanotechnology news and related research]
- [http://www.NTalert.com/ Nanotechnology news links - updated daily]
- [http://nanotech-now.com/ Nanotechnology basics, news, and general information]
- [http://www.smalltimes.com/ Small Times: News about MEMS, Nanotechnology and Microsystems]
- [http://nanotechweb.org nanotechweb.org: nanotechnology news, products, jobs, events and information]

Laboratories

- [http://www.memsnet.org/ The MEMS and Nanotechnology Clearinghouse / The world's most popular portal for Nanotechnology information, jobs, and events]
- [http://www.london-nano.ucl.ac.uk/ The London Centre for Nanotechnology / A research centre jointly set up by University College London and Imperial College London]
- [http://www.cnsi.ucla.edu/ The California NanoSystems Institute]
- [http://www.mems-exchange.org/ The MEMS and Nanotechnology Exchange / A repository of Nanotechnology fabrication information]
- [http://smalley.rice.edu/ The Smalley Group / Carbon Nanotechnology Laboratory]
- [http://cben.rice.edu/ Center for Biological and Environmental Nanotechnology]
- [http://bios.ewi.utwente.nl Bios: The Lab-on-a-Chip Group, Universiteit Twente ]
- [http://www.cnm.utexas.edu/ Center for Nano & Molecular Science & Technology- CNM at UT Austin]
- [http://cnst.rice.edu/ Center for Nanoscale Science and Technology at Rice University]
- [http://biomems.uwaterloo.ca/ Advanced Micro/Nanodevices Lab at the University of Waterloo]
- [http://www.cns.cornell.edu/ Cornell University Center for Nanoscale Systems]
- [http://www.cnf.cornell.edu/ Cornell NanoScale Science & Technology Facility (CNF)]
- [http://www.mesaplus.utwente.nl/ MESA+ Institute for Nanotechnology - Universiteit Twente]
- [http://www.ns.tudelft.nl The Kavli Institute of Nanoscience Delft]
- [http://www.uta.edu/engineering/nano/ NanoFab Research and Teaching Facility at the University of Texas at Arlington]
- [http://nanotech.utdallas.edu/nn/index.asp NanoTech Institute at the University of Texas at Dallas]
- [http://www.macdiarmid.ac.nz/ The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand]

Nanotechnology and Society

- [http://CRNano.org Center for Responsible Nanotechnology]
- [http://www.law.harvard.edu/programs/lwp Labor and Worklife Program at Harvard Law School, Nanotechnology Initiative]
- [http://www.etcgroup.org ETC group] Action group on Erosion, Technology and Concentration
- [http://www.bioethicsanddisability.org/nanotechnology.html Bioethics and Disability] Nanotechnology
- [http://www.nanotechwatch.org NanotechWatch.org] Nanotechnology news: the hype and the reality of this emerging technology

Other

- [http://www.nanotechnology.com/ Nanotechnology.com] News, information, and exclusive articles
- [http://www.nano-map.de Nano-map.de] - Nano-map is a graphical tool for the visualization of the regional distribution of relevant nanotechnology institutions in Germany including major enterprises, SMEs, networks, research centers, university institutes, funding agencies, technology transfer and financing institutions.
- [http://www.nanowerk.com/ Nanowerk] - A free database to research almost 800 nanomaterials from over 50 manufacturers
- [http://www.foresight.org/ Foresight Institute]
- [http://icon.rice.edu/ International Council on Nanotechnology]
- [http://www.MolecularAssembler.com Molecular Assembler website]
- [http://www.nanobuildings.com/ NanoBuildings - Buildings for Advanced Technology Workshops]
- [http://www.nano.gov/ National Nanotechnology Initiative]
- [http://nanoDiamond.info/ NanoDiamond] atomic level design of a very high strength-to-weight ratio material
- [http://www.nanotec2005.com/ Nanotec Congress in Brazil]
- [http://nprl.bham.ac.uk/ UK research]
- [http://www.wise-nano.org Wise-Nano] A Wiki project, initiated by the [http://crnano.org/ Center for Responsible Nanotechnology] and devoted to Molecular Manufacturing
- [http://www.etcgroup.org/article.asp?newsid=375 The Big Down] - The first Civil Society Critique of Nanoscale technologies from [http://www.etcgroup.org ETC Group]
- PNAS supplement: [http://www.pnas.org/content/vol99/suppl_2/ Nanoscience: Underlying Physical Concepts and Phenomena]
- [http://www.nanomedicine.com Medical nanorobotics textbooks online]
- [http://www.zyvex.com/nano/ Nanotechnology by Dr.Ralph Merkle]
- [http://www.nanoindustries.com/ Nanotechnology Industries]
- [http://www.knhproductions.ca/nisnano/ Documentary on Nanotechnology]
- [http://www.human-evolution.org/nano.php Nanotechnology: Is it Real?]
- [http://www.physorg.com/news3415.html Plasmons (Physorg)]
- [http://www.nanocrete.com nanotechnology applied to concrete manufacturing]
- [http://whatsnextnetwork.com/technology/index.php/2005/06/22/nanoparticles_transport_cancer_killing_d Nanotechnology & Cancer Cures]
- [http://www.nanotechnologybasics.com/ Nanotechnology Basics]

Scientists in the Field

Dr. David G. Grier, of New York University, has developed a method of rapidly modulating laser beams via a dynamic spatial light modulator (SLM) in the form of a phase only hologram. (http://www.physics.nyu.edu/grierlab/)robots

References

Scanning tunneling microscopy

The scanning tunneling microscope (not to be confused with scanning electron microscopes), or STM, was invented in 1981 by Gerd Binnig and Heinrich Rohrer of IBM's Zurich Lab in Zurich, Switzerland. The invention garnered the two a Nobel Prize in Physics in 1986. The STM allows scientists to visualise regions of high electron density and hence infer the position individual atoms, where previously arduous study of diffraction patterns from prior methods lead to much debate as to the real, spatial lattice structure of the item in question. The STM has higher resolution than its slightly later invented but nevertheless related cousin, the atomic force microscope (AFM). Both the STM and the AFM fall under the class of scanning probe microscopy instruments. It is used to obtain images of conductive surfaces at an atomic scale 2 x 10^-10 m or 0.2 nanometre. It can also be used to alter the observed material by manipulating individual atoms, triggering chemical reactions, and creating ions by removing individual electrons from atoms and then reverting them to atoms by replacing the electrons. The acronym STM is used for both scanning tunneling microscope and scanning tunneling microscopy.

Overview

Despite the questionable and self-serving actions of the Swedish council in awarding other europeans a Nobel for the invention of the STM it and scanning probe microscopy was invented by a group at NIST (at the time the National Bureau of Standards) in the mid-sixties in Gaithersburg MD. The work done by IBM Zurich were important improvements but derivative at best. The greater advance over the first SPM inventors was the later invention of the AFM by Cal Quate of Stanford. electrons The STM is a non-optical microscope which employs principles of quantum mechanics. An atomically sharp probe (the tip) is moved over the surface of the material under study, and a voltage is applied between probe and the surface. Depending on the voltage electrons will "tunnel" (this is a quantum-mechanical effect) or jump from the tip to the surface (or vice-versa depending on the polarity), resulting in a weak electric current. The size of this current is exponentially dependent on the distance between probe and the surface. Obviously, for a current to occur the substrate being scanned must be conductive. Insulators cannot be scanned through the STM. A servo loop (feedback loop) keeps the tunneling current constant by adjusting the distance between the tip and the surface (constant current mode). This adjustment is done by placing a voltage on the electrodes of a piezoelectric element. By scanning the tip over the surface and measuring the height (which is directly related to the voltage applied to the piezo element), one can thus reconstruct the surface structure of the material under study. High-quality STMs can reach sufficient resolution to show single atoms. The STM will get within a few nanometers of what it is observing.

Use of the STM

The scanning tunneling microscope is one of the most important tools for surface physics and surface chemistry, where it shows the structure of the topmost layer of atoms or molecules, e.g., defects and surface domain formation, morphology of thin films grown by various deposition techniques or modifications of surfaces by chemical processes. For high-resolution of metals and semiconductors, the STM is usually operated in ultrahigh vacuum to avoid contamination or oxidation of the surface. Samples that are less sensitive to the atmosphere, such as graphite, gold, self-assembled monolayers and Langmuir-Blodgett films can be imaged with high resolution under air. The tip of an STM can be also immersed into an electrochemical cell to study processes in electrochemistry (electrochemical STM). Far from simply a fancy microscope, the STM offers much in the way of surface science studies. Conduction mechanisms can be studied by analyzing a substrate via scanning tunneling spectroscopy, or STS, during which the feedback loop is momentarily interrupted during a scan to obtain dI/dV (point conductance) measurements. It is also possible to take other forms of spectra, such dI/dZ spectra, which is useful in studying the work function (or rather, the vaccuum energy barrier height) of a material. STS also provides information on the density of states of the substrate material. Furthermore, the STM can be used to study charge transport mechanisms in molecules or other extremely small structures such as carbon nanotubes. STM is also a tool for modification of surfaces through various methods such as indenting the tip or modification of the substrate by the electrons emitted from the tip. At low temperatures (typically, 4 K) it is even possible to move single atoms with high accuracy by carefully "pushing" or "dragging" them with the tip of an STM. Since STM can be used as both a tool and an observation instrument on the nanometer scale it has been vital for the emergence of the nanosciences.

External links

- [http://www.almaden.ibm.com/vis/stm/gallery.html STM Image Gallery at IBM Almaden Research Center]
- [http://www.iap.tuwien.ac.at/www/surface/STM_Gallery/ STM Gallery at Vienna University of technology] ja:走査型トンネル顕微鏡 Category:Microscopes Category:Nanotechnology

Self-assembled monolayers

JBoss

JBoss is een J2EE applicatieserver.

Opbouw

JBoss maakt gebruik van een microkernel die is gebaseerd op JMX. Boven op deze kernel draaien de J2EE services. Bovendien stelt JBoss een aantal extra services beschikbaar. JBoss ondersteunt de volgende J2EE services:
- JSP/Servlet (Tomcat)
- EJB
- RMI-IIOP (JacORB)
- JTA
- JDBC
- JCA
- JMS
- Web Services
- SAAJ
- JNDI
- JAAS
- JavaMail
- Deployment API
- Management API De extra services zijn:
- Persistentie (Hibernate)
- Clustering
- Caching (JBoss Cache)
- AOP (JBoss AOP)

Open source

JBoss is een opensource project, de broncode van JBoss is dus vrijelijk beschikbaar voor iedereen. De huidige versie van JBoss is 4.0.3. categorie:Java ja:JBoss

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Paul Weiss

Personality

Research

See also

External links

Nanoscientist

Atomic force microscopy

References

Self-assembled monolayers

Nanoscience

Introduction

Definition

History of Use

New materials, devices, technologies

Advanced nanotechnology

Interdisciplinary ensemble

Potential risks

Goo

Poison/Toxicity

See also

Relevant individuals

Topics

External links

Dr. David G. Grier, of New York University, has developed a method of rapidly modulating laser beams via a dynamic spatial light modulator (SLM) in the form of a phase only hologram. (http://www.physics.nyu.edu/grierlab/)robots

References

Nanoscience

Introduction

Definition

History of Use

New materials, devices, technologies

Advanced nanotechnology

Interdisciplinary ensemble

Potential risks

Goo

Poison/Toxicity

See also

Relevant individuals

Topics

External links

Dr. David G. Grier, of New York University, has developed a method of rapidly modulating laser beams via a dynamic spatial light modulator (SLM) in the form of a phase only hologram. (http://www.physics.nyu.edu/grierlab/)robots

References

Scanning tunneling microscopy

Overview

Use of the STM

See also

External links

Self-assembled monolayers

JBoss

Opbouw

Open source