nanonewbies : Messages : 29-58 of 89

Hello Nanonewbies...

Dr. Kyle Rawlings will be giving a talk about
quantum dots on Thursday, 3/6/2008.  The talk
starts at 12:00 (high-noon) in room CM-473 on
SCC's main campus.



Gerald Thurman [CS Instructor]
Scottsdale Community College
480.423.6110

#57

From: Beth Baumert <bethbaumert@...>
Date: Sat Jan 19, 2008 2:49 pm
Subject: nanopipets

bethbaumert

Offline

http://www.physorg.com/news119638230.html

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you."--BB King

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#56

From: Beth Baumert <bethbaumert@...>
Date: Sat Jan 19, 2008 2:46 pm
Subject: Graphene

bethbaumert

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http://www.electronicsweekly.com/Articles/2008/01/16/42938/graphene+shown+to+be+the+fastest+semiconductor.htm

Graphene shown to be the fastest semiconductor

by Steve Bush

Wednesday 16 January 2008

The University of Manchester has proved graphene is the fastest semiconductor.

�We knew this material is exceptionally good, but we couldn�t put a number on it,� Professor Andre Geim, director of the University�s Centre for Mesoscience and Nanotechnology told Electronics Weekly.

His team has proved mobility is above 200,000cm2/Vs at room temperature. �Greater than 100 times that of silicon, 30 times GaAs, and larger even than carbon nanotubes,� he said. �It is the only material where electrons at room temperature can move thousands of interatomic distances without scattering.�

Graphene is a chicken wire-like array of carbon atoms - effectively a single layer of graphite.

Manchester was behind the technique of isolating graphene by rubbing a lump of graphite to flake it off in sheets. �This technique will always remain the technique of choice for research and proof-of-concept,� said Geim. �Now people are finding ways of making graphene in bulk, but they are still not single layer.�

Ideally one layer only, or two at the most, of graphene would be grown on a substrate. More than this and the astounding mobility does not appear.

�Graphene which is now grown epitaxially using SiC underneath is very thin, with perhaps five to seven layers: good enough for chemical sensors, but still not good enough for electronic circuits,� said Geim.

According to him, powdered graphene is available and looking useful. �Many groups are making powder and spinning it on to surfaces for interconnect,� he said. The resulting film is transparent and could be used in displays.

Emphasising that work is �very preliminary�, Geim said: �Its nearest equivalent is ITO [indium tin oxide] and graphene is a slight electrical improvement, but the biggest advantage is indium is too expensive. Powdered graphene is certainly less expensive, easier to produce, and spinning is easier than vacuum deposition.�

Geim believes graphene-based devices like chemical gas sensors, and THz sources and detectors, could begin to materialise within three to five years.

Manchester has been working with The Institute for Microelectronics Technology in Russia, The University of Nijmegen in the Netherlands and The Department of Physics at Michigan Technological University.

"The beautiful thing about learning is that no one can take it away from
you."--BB King

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#55

From: Beth Baumert <bethbaumert@...>
Date: Sat Jan 19, 2008 2:42 pm
Subject: Nano optical effects

bethbaumert

Offline

http://www.sciencecentric.com/news/08011609.htm

Scientists have used new optical technologies to observe interactions in nanoscale systems that Heisenberg�s uncertainty principle usually would prohibit, according to a study published recently in the journal Nature.

Researchers conducted experiments with high-powered lasers and quantum dots � artificial atoms that could be the building blocks of nanoscale devices for quantum communication and computing � to learn more about physics at the nanoscale.

One common phenomenon in physics is the Fano effect, which occurs when a discrete quantum state � an atom or a molecule � interacts with a continuum state of the vacuum or the host material surrounding it. The Fano effect changes the way an atom or molecule absorbs light or radiation, said Sasha Govorov, an Ohio University theoretical physicist who is co-author on the paper.

In experiments on nanoscale systems, Heisenberg�s uncertainty principle sometimes blocks scientists from observing the Fano effect, Govorov explained. The interaction of the nanoscale system and its continuum state surroundings can�t be detected.

But in a new high-resolution laser spectroscopy experiment led by M. Kroner and K. Karrai of the Centre of NanoScience at the Ludwig-Maximilians University in Munich, Germany, scientists utilised a new method. They measured photons scattered from a single quantum dot while increasing the laser intensity to saturate the dot�s optical absorption. This allowed them to observe very weak interactions, signalled by the appearance of the Fano effect, for the first time.

A theory for the new nonlinear method was developed by Govorov. �Our theory suggests that the nonlinear Fano effect and the method associated with it can be potentially applied to a variety of physical systems to reveal weak interactions,� he said.

Scientists also can revisit older experiments on atoms by using modern tools such as highly coherent light sources that are strong enough to reveal such nonlinear Fano-effects, Karrai said. �We can explore new frontiers in quantum optics,� he noted.

The researchers were funded by the National Science Foundation (USA), SFB 631 (Germany), A. von Humboldt Foundation (Germany), Engineering and Physical Sciences Research Council (UK), SANDiE (EU), Royal Society of Edinburgh, German Excellence Initiative via the Nanosystems Initiative Munich (NIM), and Ohio University�s Nanobiotechnology Initiative.

Other co-authors on the study were S. Remi, B. Biedermann, S. Seidl and of the Ludwig-Maximilians University, W. Zhang of Ohio University; A. Badolato and P.M. Petroff of the University of California at Santa Barbara; and R. Barbour, B.D. Gerardot and R.J. Warburton of the Heriot-Watt University in Edinburgh, Scotland.

Source: Office of Research Communications, Ohio University

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you."--BB King

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#54

From: Kevin O'Connor <labs_west@...>
Date: Thu Jan 17, 2008 3:38 pm
Subject: Nanotubes Form The Darkest Material Yet Created

labs_west

Offline

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The "darkest ever" substance known to science has been made in a US laboratory.

The material was created from carbon nanotubes - sheets of carbon just one atom
thick rolled up into cylinders.

Researchers say it is the closest thing yet to the ideal black material, which
absorbs light perfectly at all angles and over all wavelengths.

  http://news.bbc.co.uk/2/hi/science/nature/7190107.stm

- --
KevinO
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#53

From: "alcott_alfred" <alcott_alfred@...>
Date: Mon Jan 14, 2008 2:00 am
Subject: Trendy Used Laptops

alcott_alfred

Offline

Looking for a cheap used laptop? Visit the website to get a sleek and
trendy laptop for you at throw away prices:
http://cheaplaptops.bigbargains.info

Reply | Forward | Messages in this Topic (5)

#52

From: "Gerald Thurman" <gerald.thurman@...>
Date: Sun Jan 13, 2008 11:32 pm
Subject: RE: Si nanowires

thurmunit

Offline

>The far-ranging potential applications of this technology include
>DOE's hydrogen fuel cell-powered "Freedom CAR," and personal power-jackets
>that could use heat from the human body to recharge cell-phones and other
>electronic devices.
>
>http://www.nanotech-now.com/news.cgi?story_id=27387
>
I had not heard of Freedom CAR before (nor 21st Century Truck).

"FreedomCAR is a research initiative focused on collaborative, pre-competitive,
high-risk research to develop the component technologies necessary to provide
a full range of affordable cars and light trucks that will free the nation's
personal transportation system from petroleum dependence and harmful vehicle
emissions without sacrificing freedom of mobility and freedom of vehicle
choice.

http://eere.pnl.gov/freedom-car/



Gerald Thurman [CS Instructor]
Scottsdale Community College
480.423.6110

#51

From: Beth Baumert <bethbaumert@...>
Date: Sat Jan 12, 2008 10:19 pm
Subject: Si nanowires

bethbaumert

Offline

Abstract:
Energy now lost as heat during the production of electricity could be harnessed through the use of silicon nanowires synthesized via a technique developed by researchers with the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) at Berkeley. The far-ranging potential applications of this technology include DOE's hydrogen fuel cell-powered "Freedom CAR," and personal power-jackets that could use heat from the human body to recharge cell-phones and other electronic devices.

http://www.nanotech-now.com/news.cgi?story_id=27387

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#50

From: "richard_winson2001" <richard_winson2001@...>
Date: Sat Jan 12, 2008 7:53 am
Subject: Trendy Used Laptops

richard_wins...

Offline

Looking for a cheap used laptop? Visit the website to get a sleek and
trendy laptop for you at throw away prices:
http://cheaplaptops.bigbargains.info

Reply | Forward | Messages in this Topic (5)

#49

From: "richard_winson2001" <richard_winson2001@...>
Date: Sat Jan 12, 2008 7:48 am
Subject: Trendy Used Laptops

richard_wins...

Offline

Looking for a cheap used laptop? Visit the website to get a sleek and
trendy laptop for you at throw away prices:
http://cheaplaptops.bigbargains.info

Reply | Forward | Messages in this Topic (5)

#48

From: Beth Baumert <bethbaumert@...>
Date: Fri Jan 11, 2008 11:58 pm
Subject: Fwd: [AZNANOTECH_NEWS 280] Special Seminar From Micro to Nano Robotics

bethbaumert

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this sounds interesting, if anybody cares to drive to Tucson:

Mike Berman <michaeljberman@...> wrote:

Date: Fri, 11 Jan 2008 16:40:34 -0700
From: "Mike Berman" <michaeljberman@...>
To: AZNANOTECH@googlegroups.com
Subject: [AZNANOTECH_NEWS 280] Special Seminar From Micro to Nano Robotics

The Special Seminar notices is being sent out on behalf of Aerospace and Mechanical Engineering, University of Arizona.

Mike Berman

Special Seminar
Tuesday, January 15, 2008
4:00 pm
AME Lecture Hall, Room S212
Aerospace and Mechanical Engineering

Dr. Bradley J. Nelson
Professor of Robotics and Intelligent Systems
Swiss Federal Institute of Technology (ETH)
Zurich
www.iris.ethz.ch

From Micro to Nano Robotics

Robots are currently exploring many environments that are difficult if not impossible for humans to reach, such as the edge of the solar system, the planet Mars, volcanoes on Earth, and the undersea world. The goal of these robotic explorers is to obtain knowledge about our universe and to answer fundamental questions about life and human origins. Microrobotics has entered this field by exploring life at a much smaller scale and more fundamental level. Microrobotic systems for physically exploring the structures of biological cells are being developed, and robotic motion planning strategies are being used to investigate protein folding. Microrobotic mechanisms have been used to investigate organism behaviors, such as the flight dynamics of fruit flies as well as the neurophysiology that govern many other biologically interesting behaviors. These recent research efforts and others like them illustrate how several areas of robotics research are rapidly converging to create this new discipline I refer to as BioMicroRobotics. These new directions in robotics represent only a beginning and indicate that robotics research, and biomicrorobotics in particular, has the capability of making significant contributions in the understanding of life. In moving from the micro domain to nanometric scales, completely different issues in developing nanorobotic systems and in their application arise. The second part of the talk will present recent efforts at the Institute of Robotics and Intelligent Systems at ETH-Zurich in fabricating nanometer scale robotic components.

Tuesday, January 15, 2008
4:00 pm
AME Lecture Hall, Room S212

Refreshments and socializing 3:45 pm at the east end of the AME courtyard

Dianne Smith
Program Coordinator
Department of Aerospace & Mechanical Engineering
N705
Phone: 626-8724
Fax: 626-5229

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#47

From: Beth Baumert <bethbaumert@...>
Date: Fri Jan 11, 2008 6:22 pm
Subject: Nanotechnology class

bethbaumert

Offline

Happy new year Nanonewbies,

If you would like to learn more about Nanotechnology, please consider taking our one-credit class, ECE 106, which will meet on Fridays at 9:30 am.

http://scinfo.sc.maricopa.edu/sis/schedule/schedule?ECE&20082&SITE=MAIN

We need ten people to register in order for the class to proceed.

Thank you
Dr. B

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#46

From: Beth Baumert <bethbaumert@...>
Date: Wed Jan 9, 2008 12:11 am
Subject: Fwd: AZBio 2008 Updates & Reminder

bethbaumert

Offline

events@... wrote:

From: <events@...>
To: bethbaumert@...
Subject: AZBio 2008 Updates & Reminder
Date: Tue, 08 Jan 2008 17:00:05 -0700

Dear colleague,

We hope you had a great holiday season! With the beginning of the new year, we're pleased to provide you with the newest edition of the Arizona BioInsider�, the newsletter of the Arizona BioIndustry Association. Please visit http://www.azbio.org/pdf/jan2008.pdf to view the PDF newsletter.

The January edition of the BioInsider features:
Bioscience Roadmap Update
Getting to know AZBio
NAU and TGEN win $4.5M grant
AZ Cancer Center wins $12M grant
Local research lab sold for $40M
SBIR/STTR grant writing assistance program

If you have not already done so, please plan to join us for one of the Getting to know AZBio events in January where we will share some of our plans for 2008, as well as hear from you what you would like to see from the Arizona BioIndustry Association - AZBio.
These events are free of charge and are open to members and non-members alike.
To register, please click on the link below for the "Getting to Know AZBio" event that is most convenient for you.
SOUTHERN ARIZONA
Tuesday, January 15, 2008 from 5:00 p.m. to 7:00 p.m. at Ventana Medical Systems. Click here to register.

GREATER PHOENIX AREA
Wednesday, January 16, 2008 from 11:30 a.m. to 1:30 p.m. at Medtronic. Click here to register.

NORTHERN ARIZONA
Date and location TBD.

Last, but not least, take advantage of this last chance to put your company on the Greater Phoenix and Tucson High-Tech & Bioscience Map.

As Arizona's high-tech and bioscience sectors grow and mature, the need to document our progress becomes increasingly important. The Flinn Foundation and the Arizona Department of Commerce are helping to facilitate an effort to research the history of bioscience and high-tech firms in the Greater Phoenix and Tucson areas. The project, led by a professor at Virginia Polytechnic Institute and State University with expertise in this area, will result in a poster illustrating the genealogy of our local bioscience and high-tech industries.

The research portion of this project involves an online survey. We would be most appreciative if you or another representative of your company could devote a few minutes to complete the survey at the following link: http://www.surveymonkey.com/s.aspx?sm=UkCBAG_2fSQFBhZDlJBsfscA_3d_3d

The survey is available until January 15, 2008. Questions? Please don't hesitate to contact Heike Mayer, Assistant Professor in Urban Planning, Virginia Tech, at 703-706 8122 or heikem@....

We're looking forward to seeing you at one of our future events!

Best wishes,

          Arizona BioIndustry Association
        Bob Eaton Natascha Hebell-Fernando

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#45

From: Beth Baumert <bethbaumert@...>
Date: Sun Jan 6, 2008 5:30 pm
Subject: Thermal transistors

bethbaumert

Offline

http://www.spectrum.ieee.org/jan08/5850

Thermal Transistor: The World's Tiniest Refrigerator By Alexander Hellemans

First Published January 2008

Thermal transistors refrigerate one electron at a time and physicists plan to compute with heat

Comments (0)

1 January 2008�Traditionally, heat and electronics don�t agree. But physicists in Europe and Asia are beginning to see some signs of cooperation. A Finnish-Italian team has demonstrated that electrons in a specially designed transistor can carry away heat, making the device they built the smallest known refrigerator. Another team, from Singapore, has shown that heat can carry information in a transistor-like device, just like electrons do in conventional computers.

Researchers from the Helsinki University of Technology, in Finland, and the Scuola Normale Superiore in Pisa, Italy, have created a tiny transistor�resembling in structure if not in composition the field-effect transistors in ICs�that they call a single-electron refrigerator. Two superconducting electrodes are connected to a small micrometer-sized copper slab, about 2 mm long and 1/5 mm wide. These electrodes are analogous to the source and drain of a conventional transistor, except that they are electrically isolated from the copper by a thin layer of aluminum oxide. (Two extra electrodes are attached on both sides of the source and drain for measurement purposes.) Along the copper island is placed the �gate,� an electrode that controls the flow of electrons through the copper slab.

At temperatures below 1 K, electrons can pass from the copper slab, which is not superconducting, to the superconducting aluminum probes via a quantum mechanical trick called tunneling.

Then, by applying a voltage to the source and drain, electrons are pushed through the copper island. Whenever an electron is admitted to the copper island, another leaves. But the device also acts like a filter, allowing only the �hottest� electrons, those with higher energy, to leave the island. So when a current flows from the source to the drain, the copper island becomes depleted of hot electrons, thus lowering its overall temperature. The researchers found that applying a certain voltage to the gate electrode adjusts the electrostatic repulsion between electrons, called the �Coulomb blockade.� Tuning the gate voltage properly leads to a point where only one electron goes through the device at a time. The turnstile-filter combination improves not only the cooling efficiency but also lets you switch on and off the flow of heat from the transistor.

Although the cooling power of the device is very small and only effective at very low temperatures to start with, the fact that the heat flux can be controlled at all makes the device interesting for future electronics, says team leader Jukka Pekola, of Helsinki University of Technology. The technology could find a use in cooling devices that already operate at low temperatures, such as superconducting transistors or supercooled magnetometers, known as superconducting quantum interference devices, or SQUIDs, says team member Francesco Giazotto, of Scuola Normale Superiore.

In a separate development, a team of physicists at the National University of Singapore have come up with a plan for a device that could use phonons, vibrations in a crystal lattice that carry heat, as bits of information. Phonons are usually viewed as a nuisance because they produce noise in electronic circuits and cause other problems. But the Singaporean physicists report that they have modeled what they call �thermal logic gates,� based on the concept of thermal transistors, that compute with phonons. A thermal transistor would consist of two terminals, called source and drain in an analogy with the conventional transistor, while a third terminal that is linked to the source functions like a gate, controlling the flow of phonons from the drain to the source.

Just as electrons flow because of a difference in voltage, phonons flow because of a difference in temperature. But if the lattice vibration spectra�the spectrum of energies of phonons�in the two terminals don�t match, very little heat can flow between them. The Singapore team says that by injecting lattice vibrations from the gate into the source, it becomes possible to match the source�s vibrational spectrum to that of the drain segment, allowing the phonons to flow.

The team produced several models of logic gates, in which phonons have taken over the role of electrons. This research should ultimately lead to the construction of thermal computers, says Li Bao Wen, a professor of physics at the National University of Singapore. �If one can build a logic gate, one should be able to build a computer,� he says. Research groups, such as a group at the University of California at Berkeley led by Alex Zettl and Arunava Majumdar, are already trying to build thermal devices. The Berkeley group has constructed a thermal rectifier consisting of a nanotube that conducts heat better in one direction than the other, and they are now experimenting with thermal transistors. �We do have our own plans to do this,� says Bao Wen.

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#44

From: Beth Baumert <bethbaumert@...>
Date: Sun Jan 6, 2008 5:04 pm
Subject: some good Materials Science

bethbaumert

Offline

http://www.nanotech-now.com/news.cgi?story_id=27213

Abstract:
As structures made of metal get smaller � as their dimensions approach the micrometer scale (millionths of a meter) or less � they get stronger. Scientists discovered this phenomenon 50 years ago while measuring the strength of tin "whiskers" a few micrometers in diameter and a few millimeters in length. Many theories have been proposed to explain why smaller is stronger, but only recently has it become possible to see and record what's actually happening in tiny structures under stress.

Smaller is Stronger - Now Scientists Know Why

BERKELEY, CA | Posted on January 2nd, 2008

Andrew Minor, of the Materials Sciences Division in the Department of Energy's Lawrence Berkeley National Laboratory, with colleagues from Hysitron Incorporated and the General Motors Research and Development Center, used the In Situ Microscope at the National Center for Electron Microscopy (NCEM) to record what happens when pillars of nickel with diameters between 150 and 400 nanometers (billionths of a meter) are compressed under a flat punch made of diamond. The transmission electron microscope is equipped so that samples can be stressed, measured, and videotaped while being observed under the electron beam.

"What controls the deformation of a metal object is the way that defects, called dislocations, move along planes in its crystal structure," Minor says. "The result of dislocation slip is plastic deformation. For example, bending a paper clip causes its trillions of dislocations per square centimeter to tangle up and multiply as they run into one another and slide along numerous slip planes."

In general, mechanical deformation tends to increase the number of dislocations in a material. But for small-scale structures, with a much greater proportion of surface area to volume, the process can be very different. The videotaped images from the electron microscope helped the researchers understand why nanoscale nickel pillars are so strong by allowing them to observe changes in the microstructure of the pillars during deformation � including a never-before-seen process the researchers dubbed "mechanical annealing." (In bulk materials, annealing, a treatment that reduces the density of defects, is usually accomplished by heating.)

Minor says, "The first thing we observed was that, before the test, the nanoscale pillars of nickel were full of dislocations. But as we compressed the pillar, all the dislocations were driven out of the material � literally reducing the dislocation density by 15 orders of magnitude and producing a perfect crystal. We called this effect mechanical annealing."

The pillars Minor and his colleagues tested were machined from pure nickel using a focused ion beam (FIB), a new technique for small-scale mechanical-compression testing first described in 2004 by Michael Uchic of the U.S. Air Force Research Laboratory and his colleagues. The FIB technique makes it possible to create much smaller structures than the metal "whiskers" first studied in the 1950s, which are made by growing crystals.

Some of the dislocations the researchers observed in the machined pillars were relatively shallow and caused by the ion beams themselves. Others extended through the crystal and were presumably pre-existing defects. Under compression, mechanical annealing caused both kinds of defect to vanish.

"Essentially all the dislocations escape from the crystal at the surface, and you do not get storage of dislocations like you would in larger crystals," Minor says. "What results is a process called 'dislocation starvation,' recently proposed by William D. Nix of Stanford, among others, which has quickly became one of the leading theories of why smaller structures are stronger."

Minor explains, "The idea is that if dislocations escape the material before they can interact and multiply, there are not enough active dislocations to enable the imposed deformation. The structure can only deform after new dislocations are created." This is precisely the process he and his colleagues observed with NCEM's In Situ Microscope, strong evidence that "dislocation starvation" is the correct explanation for the increased strength of small structures.

What happens if a defect-free nanoscale nickel pillar continues to be compressed? Something has to give, which happens when new sources of dislocation "nucleate" in the material. As the existing dislocations disappear in the pillar because of mechanical annealing, the nucleation of new dislocation sources happens at progressively higher stresses.

In the pillar structures, plastic deformation may take the form of sudden flattening, bulging, twisting, or shearing of the pillar, as bursts of new dislocations propagate through it. Or the hardened pillars, made stronger by mechanical annealing, may punch right down into the substrate � even though pillar and substrate are the same continuous piece of metal. Both processes were captured in the In Situ Microscope's dramatic videotaped experiments.

The FIB machining used by the NCEM researchers produced nickel pillars that were slightly tapered, and the researchers noted that this geometry affected where and how plastic deformation occurred, generally being greater in the smaller-diameter, free end (top) of the pillar.

In larger pillars, those approaching 300 nanometers in diameter, mechanical annealing was not complete, and some dislocations remained visible even after compression. Yet even these pillars exhibited enhanced strength, and progressively higher stresses were needed to continue deformation � underlining the point that it is the creation of mobile defects that determines strength in these small volumes.

"The beauty of the pillar-testing geometry is that we can straightforwardly define stress. Then we can correlate the measured stresses with discrete plastic events recorded in situ and more clearly interpret the quantitative data from our experiments," says Minor. "The debate over what determines the strength of a small structure has come down to almost a chicken-and-egg question � is something strong because you need a high stress to move a dislocation that is already there? Or is it strong because you need a high stress to nucleate a new dislocation? In this case, it seems that source nucleation � that is, the 'egg' � is the determining factor."

"Mechanical annealing and source-limited deformation in submicrometre-diameter Ni crystals," by Z.W. Shan, Raj Mishra, S.A. Syed Asif, Oden L. Warren, and Andrew M. Minor, appears in the January, 2008 issue of Nature Materials, advance online publication 23 December, 2007 at http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat2085.html. This work was partially supported by a grant from the US Department of Energy to Hysitron, Inc., and also by a grant from the DOE Office of Science, Office of Basic Energy Sciences.

####

About Berkeley Lab
Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our website at http://www.lbl.gov .

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#43

From: Beth Baumert <bethbaumert@...>
Date: Sun Jan 6, 2008 4:37 pm
Subject: more solar work

bethbaumert

Offline

http://www.gizmag.com/researchers-developing-solar-technology-that-works-at-night/8574/

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#42

From: Beth Baumert <bethbaumert@...>
Date: Sun Jan 6, 2008 4:20 pm
Subject: solar cell work

bethbaumert

Offline

from Nanotech News:

Nanotechnology aids large-area solar cell
eetimes.com December 31st, 2007 A scientist at Israel's Bar-Ilan University claims that he has managed to create a solar cell 100 times bigger than a typical solar cell, using nanotechnology methods. Professor Arie Zaban, head of Bar-Ilan University's Nanotechnology Institute, is an expert in photovoltaics. In a recently patented technique, Professor Zaban demonstrated how metallic wires mounted on conductive glass can form the basis of solar cells with efficiency similar to that of conventional, silicon-based cells, but that are much cheaper to produce. While Professor Zaban's earlier efforts produced photovoltaic cells one square centimeter in size, he has now achieved a cell measuring 10 centimeters by 10 centimeters, which he claimed would boost the technique's usefulness in producing commercial amounts of solar power. "Initially, we created linked arrays of very small cells, which led to a loss of efficiency because the sunlight hitting the space between the cells was not converted to electricity," Professor Zaban said. Professor Zaban said the cell is now a practical choice for solar energy production. "We've found a way to produce platinum nanodots tiny crystals measuring only a few nanometers in diameter," Professor Zaban said, adding that this highly reactive metal is an important part of his solar cell's operation. "Thanks to this technique now under consideration for a patent we reduce the amount of platinum needed by a factor of 40." In previous research, Professor Zaban developed a low-cost method of depositing semiconductor material in a sponge-like array on top of flexible plastic sheets. Key to his system is the use of an organic dye that allows the semiconductor, transparent in its natural form, to absorb light.

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#41

From: Beth Baumert <bethbaumert@...>
Date: Thu Jan 3, 2008 11:53 pm
Subject: battery breakthrough

bethbaumert

Offline

http://www.nanotech-now.com/news.cgi?story_id=27034

Stanford's nanowire battery holds 10 times the charge of existing ones

PALO ALTO, CA | Posted on December 18th, 2007

The new version, developed through research led by Yi Cui, assistant professor of materials science and engineering, produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. A laptop that now runs on battery for two hours could operate for 20 hours, a boon to ocean-hopping business travelers.

"It's not a small improvement," Cui said. "It's a revolutionary development."

The breakthrough is described in a paper, "High-performance lithium battery anodes using silicon nanowires," published online Dec. 16 in Nature Nanotechnology, written by Cui, his graduate chemistry student Candace Chan and five others.

The greatly expanded storage capacity could make Li-ion batteries attractive to electric car manufacturers. Cui suggested that they could also be used in homes or offices to store electricity generated by rooftop solar panels.

"Given the mature infrastructure behind silicon, this new technology can be pushed to real life quickly," Cui said.

The electrical storage capacity of a Li-ion battery is limited by how much lithium can be held in the battery's anode, which is typically made of carbon. Silicon has a much higher capacity than carbon, but also has a drawback.

Silicon placed in a battery swells as it absorbs positively charged lithium atoms during charging, then shrinks during use (i.e., when playing your iPod) as the lithium is drawn out of the silicon. This expand/shrink cycle typically causes the silicon (often in the form of particles or a thin film) to pulverize, degrading the performance of the battery.

Cui's battery gets around this problem with nanotechnology. The lithium is stored in a forest of tiny silicon nanowires, each with a diameter one-thousandth the thickness of a sheet of paper. The nanowires inflate four times their normal size as they soak up lithium. But, unlike other silicon shapes, they do not fracture.

Research on silicon in batteries began three decades ago. Chan explained: "The people kind of gave up on it because the capacity wasn't high enough and the cycle life wasn't good enough. And it was just because of the shape they were using. It was just too big, and they couldn't undergo the volume changes."

Then, along came silicon nanowires. "We just kind of put them together," Chan said.

For their experiments, Chan grew the nanowires on a stainless steel substrate, providing an excellent electrical connection. "It was a fantastic moment when Candace told me it was working," Cui said.

Cui said that a patent application has been filed. He is considering formation of a company or an agreement with a battery manufacturer. Manufacturing the nanowire batteries would require "one or two different steps, but the process can certainly be scaled up," he added. "It's a well understood process."

Also contributing to the paper in Nature Nanotechnology were Halin Peng and Robert A. Huggins of Materials Science and Engineering at Stanford, Gao Liu of Lawrence Berkeley National Laboratory, and Kevin McIlwrath and Xiao Feng Zhang of the electron microscope division of Hitachi High Technologies in Pleasanton, Calif.

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#40

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Date: Sat Dec 29, 2007 7:03 am
Subject: GENUINE NETINCOME

genuine_income3

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#39

From: Beth Baumert <bethbaumert@...>
Date: Fri Dec 21, 2007 10:43 pm
Subject: carbon-based electronics

bethbaumert

Offline

http://www.sciencedaily.com/releases/2007/12/071218192013.htm

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#38

From: Beth Baumert <bethbaumert@...>
Date: Wed Dec 19, 2007 9:33 pm
Subject: quantum dots

bethbaumert

Offline

http://technology.newscientist.com/article/dn13023-quantumdot-displays-could-outshine-their-rivals.html

Quantum-dot displays could outshine their rivals

14:55 10 December 2007

The quantum-dot LEDs require just 3 to 4 volts to run for over 300 hours non-stop (Image: Nature)

The size of the quantum dots can be tuned to produce several different colours (Image: Nature)

The brightest quantum-dot LEDs yet made could provide lighting for displays that are clearer and richer in colour, as well as being cheaper to make, than existing ones.

The devices could be used to make better displays for mobile phones and PDAs, and to light larger flat-panel TV screens, say researchers based in China and the US.

Quantum dots are nanoscale semiconductors that confine electrons in three dimensions. In this case, the quantum dots have a cadmium selenide core and a zinc sulphide "shell". Electrons are excited to higher energy levels in the core and the shell, then fall into the empty spaces, or "holes", left behind. The dot then forms an "exciton" and emits a particle of light.

Changing the size of a QDLED makes it emit a different wavelength of light � producing red, orange, yellow, or green light. The devices also only need about 3 to 4 volts to operate and can run for over 300 hours without losing any brightness.

Although standard LEDs are far more efficient, QDLEDs could be better in other ways. The range of colours and intensity of light produced by QDLEDs promise to be better than alternative technologies.

"The brightness of the best LCD monitor on the market today is 500 candelas per square metre and the brightness of room light is about 2000 cd/m²," says Andrew Wang of Ocean NanoTech in Fayetteville, Arkansas, which developed the quantum dots. "Our QDLEDs have reached 9000 cd/m² in brightness, which makes them the brightest in the world."

Purer colours

QDLEDs are also relatively easy to make, using solution-processing techniques, such as spin coating, ink-jet printing and roll-to-roll printing, which is useful for flexible-screen applications. Organic LEDs, by contrast, are made using more complicated techniques like vacuum evaporation or vapour deposition.

Although similar devices were made by researchers at MIT in 2002, their QDLEDs had brightness values of around 7000 cd/m² and contained only a single layer of quantum dots. The new devices contain multiple quantum dot layers to make them brighter, Wang explains.

The Ocean NanoTech researchers, together with Yongfang Li and Qingjiang Sun at the Chinese Academy of Sciences, are now working hard to optimise the structures of the quantum dots to further increase the lifetime and power efficiency of the devices.

For the technology to be incorporated into a product, however, it may be necessary to demonstrate the same physical phenomena using a material other than cadmium, which is a highly toxic heavy metal.

Journal reference: Nature Photonics (DOI: 10.1038/nphoton.2007.226)

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#37

From: Beth Baumert <bethbaumert@...>
Date: Wed Dec 19, 2007 9:21 pm
Subject: quantum computing

bethbaumert

Offline

http://www.nanotech-now.com/news.cgi?story_id=26889

December 11th, 2007

UQ scientists make a quantum leap in research

Abstract:
University of Queensland researchers are among an international team to have made the first ever execution of a quantum calculation, a major step towards building the first quantum computers.

Story:
Professor Andrew White, from UQ's Centre for Quantum Computer Technology together with colleagues from the University of Toronto in Canada, said by manipulating quantum mechanically entangled photons - the fundamental particles of light - the prime factors of the number 15 were calculated.

"Prime numbers are divisible only by themselves and one, so the prime factors of 15 are three and five," Professor White said.

"Although the answer to this problem could have been obtained much more quickly by querying a bright eight-year-old, as the number becomes bigger and bigger the problem becomes more and more difficult.

"What is difficult for your brain is also difficult for conventional computers. This is not just a problem of interest to pure mathematicians: the computational difficulty of factoring very large numbers forms the basis of widely used internet encryption systems."

Ben Lanyon, UQ doctoral student and the research paper's first author, said calculating the prime factors of 15 was a crucial step towards calculating much larger numbers, which could be used to crack cryptographic codes that are unbreakable using conventional computers.

"Our goal is not to break these codes in practice, but to show that they can be broken, and motivate a move to a more secure system," Mr Lanyon said.

"These codes form the basis of most banking and computer security and has implications of how we keep all data secure in the future."

Professor White said in any computer a problem must be broken down into manageable chunks.

"Classical computers use two-level systems called bits (binary digits) while quantum computers use two-level 'quantum-mechanical' systems called qubits (quantum bits)," he said.

"A qubit is like a coin that can be heads (on), tails (off) or simultaneously heads AND tails (on and off) or any possible combination in-between.

"This is impossible with normal bits but one qubit can be in two possible states, two qubits can be in four, three qubits in eight, and so on. Quantum memory sizes grow exponentially with the number of qubits.

"Functional large-scale quantum computers may be as many years away, and it is hard to know how they will change the world, but change our world they will."

The research will be published in the prestigious Physical Review Letters later this month.

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#36

From: "Gerald Thurman" <gerald.thurman@...>
Date: Wed Dec 12, 2007 5:47 pm
Subject: Field Trip Sometime In The Spring

thurmunit

Offline

I attended a Techie Tuesday last night (2007.12.11).  Techie Tuesdays (which
now go by a different name) are held the 2nd Tuesday of the month in downtown
Tempe.  Last night I met one of the people who runs the Nanofab lab at ASU
and we will be having a field trip to ASU sometime during Spring 2008.

[side-bar] The front-page of today's Arizona Republic had a story titled
"TGen finds key prostate cancer gene."  One of TGen's key scientists in this
area of research is Dr. John Carpten, who was a guest speaker at SCC during
the Spring 2006 semester.

Gerald Thurman [CS Instructor]
Scottsdale Community College
480.423.6110

#35

From: "Gerald Thurman" <gerald.thurman@...>
Date: Tue Dec 11, 2007 9:00 pm
Subject: Nanotech Course in the Spring

thurmunit

Offline

Hello Nanonewbies at SCC...

We have tentatively decided to offer a 1-credit
Survey of Nanotechnology (ECE106) during the
Spring 2008 semester. The course will meet
on Friday mornings from 9:30am to 10:30am.

Please let me know via email if you'd be interested
in taking this course.

Gerald Thurman [CS Instructor]
Scottsdale Community College
480.423.6110

#34

From: "Gerald Thurman" <gerald.thurman@...>
Date: Tue Dec 4, 2007 6:15 pm
Subject: Last Meeting This Year

thurmunit

Offline

Hello...

Our last meeting of the year will be Thursday,
6 December 2007, at high-noon in room CM-462.

Gerald Thurman [CS Instructor]
Scottsdale Community College
480.423.6110

#33

From: Beth Baumert <bethbaumert@...>
Date: Mon Nov 19, 2007 3:26 am
Subject: quantum dots

bethbaumert

Offline

http://www.nanotech-now.com/news.cgi?story_id=26392

NRL researchers develop optical technique for controlling electron spins in quantum dot ensembles

Washington, DC | Posted on November 15th, 2007

An electron spin localized in a quantum dot is the quantum bit, which is the basic unit for solid-state based quantum computing and quantum information processing. The spin replaces a classical digital bit, which can take on two values, usually labeled 0 and 1. The electron spin can also take on two values. However, since it is a quantum object, it can also take all values in between. Obviously, such a quantum unit can hold much more information than a classical one and, even more importantly the use of such quantum bits makes certain computer calculations exponentially more efficient than those using a standard computer. That is why, scientists around the world are trying to find an efficient way to control and manipulate the electron spin in a quantum dot in order to enable new quantum devises using magnetic and electric fields.

Until now, the major problem with using charged quantum dots in such devices is that the electron spins in different quantum dots are never identical. The electron spin precession frequencies in an external magnetic field are different from each other due to small variations of the quantum dot shape and size. In addition, the electron spin precession frequency has a contribution of a random hyperfine field of the nuclear spins in the quantum dot volume. This makes a coherent control and manipulation of electron spins in an ensemble of quantum dots impossible and pushes researchers to work with individual spins and to develop single spin manipulation techniques, which are much more complicated than an ensemble manipulation technique.

The team of researchers at the University of Dortmund, NRL and the University of Bochum has taken a significant step toward solving this problem by suggesting a new technique that would allow coherent manipulations of an ensemble of electron spins. Last year in a Science publication (Science, vol. 313, 341 (2006)), the same research team demonstrated a method, whereby a tailored periodic illumination with a pulsed laser can drive a large fraction of electron spins (up to 30%) in an ensemble of quantum dots into a synchronized motion. In the new Science publication, the team shows that almost the whole ensemble of electron spins (90%) precesses coherently under periodic resonant excitation. It turns out that the nuclear contribution to the electron spin precession acts constructively by focusing the electron spin precession in different quantum dots to a few precession modes controlled by the laser excitation protocol, instead of acting as a random perturbation of electron spins, as it was thought previously. The modification of the laser protocol should allow scientists to reach a situation in which all electron spins have the same precession frequency, in other words to make all spins identical.

Future efforts involving the use of these identical electron spins will focus on demonstrating all coherent single q-bit operations using an ensemble of charged quantum dots. Another important use of such ensembles for quantum computing will be the demonstration of a quantum-dot gate operation. The macroscopic coherent precession of the electron spin ensemble will allow scientists to study several optical coherent phenomena, such as electromagnetically induced transparency and slow light, for example.

The research was conducted by Dr. Alex Greilich, Prof. Dmitri R. Yakovlev, Dr. Irina A. Yugova and Prof Manfred Bayer from the Institute Experimental Physics II of the University of Dortmund, Germany; Dr. Andrew Shabaev and Dr. Alexander L. Efros from NRL; and Dr. D. Reuter, and Prof. A. D. Wieck from the Physics Institute of the University of Bochum, Germany.

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#32

From: Beth Baumert <bethbaumert@...>
Date: Mon Nov 19, 2007 3:16 am
Subject: Nano electronic noses

bethbaumert

Offline

http://www.nanowerk.com/spotlight/spotid=3331.php

The concept of e-noses - electronic devices which mimic the olfactory systems of mammals and insects - is very intriguing to researchers involved in building better, cheaper and smaller sensor devices. A better understanding of the reception, signal transduction and odor recognition mechanisms for mammals, combined with achievements in material science, microelectronics and computer science has led to significant advances in this area. Nevertheless, the olfactory system of even the simplest insects is so complex that it is still impossible to reproduce it at the current level of technology. For example, the biological receptors are regularly replaced during the life of mammals in a very reliable way so that the receptor array does not require to be recalibrated. The performance of existing artificial electronic nose devices is much more dependent on the sensor's aging and, especially, the sensor's replacement and frequently require a recalibration to account for change. Moreover, current electronic nose devices based on metal oxide semiconductors or conducting polymers that specifically identify gaseous odorants are typically large and expensive and thus not adequate for use in micro- or nano-arrays that could mimic the performance of the natural olfactory system. Nanotechnology is seen as a key in advancing e-nose devices to a level that will match the olfactory systems developed by nature. Nanowire chemiresistors are seen as critical elements in the future miniaturization of e-noses. It is now also believed that single crystal nanowires are most stable sensing elements what will result in extending of life-time of sensors and therefore the recalibration cycle. Last year we reported on a research effort Towards The Nanoscopic Electronic Nose. Scientists involved in this effort now report a second-generation, far more advanced e-nose system based on metal oxide nanowires. ...

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#31

From: Kevin O'Connor <labs_west@...>
Date: Sat Nov 17, 2007 10:12 pm
Subject: NASA Wins Nanotechnology Award

labs_west

Offline

http://science.slashdot.org/article.pl?sid=07/11/17/1225259

http://www.nasa.gov/centers/goddard/news/topstory/2007/nanotube.html

"NASA is rarely associated with nanotechnologies. But one of its researchers
working at the NASA's Goddard Space Flight Center just received a Nanotech
Briefs
Nano 50 award for a manufacturing process for high-quality carbon nanotubes
(CNTs). Because of its ability to produce bundles of CNTs without using a metal
catalyst, this method is simpler, safer, and cheaper than current ones. The CNTs
produced by this process are also purer and well suited for medical
applications."
--
KevinO

#30

From: "jdnagy63" <john.nagy@...>
Date: Thu Nov 15, 2007 9:04 pm
Subject: Nano device from seaweed

jdnagy63

Offline

This article doesn't use the phrase, "nanotechnology," but essentially
some folks at Rensselaer Polytech have developed a nano device for
stem cell treatments. Here's the link and the URL:

news.rpi.edu/update.do

Cheers,

John

#29

From: "Gerald Thurman" <gerald.thurman@...>
Date: Tue Nov 6, 2007 1:54 pm
Subject: NewsFactor.com Reports About a Nanoradio

thurmunit

Offline

Posted to NewsFactor.com on 5 November 2007.

"To construct the world's first 'nanoradio,' researchers placed a nanotube
in a   vacuum between two electrodes and connected the device to a battery.
The physicists then charged one of the nanoradio's electrodes to 'pull1 on
the nanotube's tip, thereby adjusting the strand's length to correspond with
the desired frequency."

Researchers Build Nanoradio from Atoms
http://www.newsfactor.com/story.xhtml?story_id=01200000EJ5C

Gerald Thurman [CS Instructor]
Scottsdale Community College
480.423.6110