August 19, 2009, 6:58 AM CT

Nuclear fusion research key to advancing computer chips

Researchers are adapting the same methods used in fusion-energy research to create extremely thin plasma beams for a new class of "nanolithography" mandatory to make future computer chips.

Current technology uses ultraviolet light to create the fine features in computer chips in a process called photolithography, which involves projecting the image of a mask onto a light-sensitive material, then chemically etching the resulting pattern.

New nanolithography will be needed to continue advances in computer technology and to extend Moore's law, an unofficial rule stating that the number of transistors on integrated circuits, or chips, doubles about every 18 months.

"We can't make devices much smaller using conventional lithography, so we have to find ways of creating beams having more narrow wavelengths," said Ahmed Hassanein, the Paul L. Wattelet Professor of Nuclear Engineering and head of Purdue's School of Nuclear Engineering.

The new plasma-based lithography under development generates "extreme ultraviolet" light having a wavelength of 13.5 nanometers, less than one-tenth the size of current lithography, Hassanein said.

Nuclear engineers and researchers at Purdue and the U.S. Department of Energy's Argonne National Laboratory are working to improve the efficiency of two techniques for producing the plasma: One approach uses a laser and the other "discharge-produced" method uses an electric current......... Posted by: Kevin      Read more         Source

August 18, 2009, 11:05 PM CT

Scientists' strategic reading of research

The revolution in scientific publishing that has been promised since the 1980s is finally about to take place, as per two University of Illinois experts in information science.

Allen H. Renear and Carole L. Palmer, professors of library and information science at Illinois, say that as techniques originally designed to organize and share scientific data are integrated into scientific publishing, scientists' long-standing practice of reading "strategically" will be dramatically enhanced.

"Eventhough it's natural to believe that researchers search online to find individual articles to read, that isn't commonly what's going on," Renear said. "Scientists actually try to avoid reading as much as possible, relying instead on indexing, citations and peer recommendations as indicators of scientific relevance".

"Researchers skim journal articles to discover valuable information. They scan for terminology, segments, diagrams and summaries of particular interest. But they don't read individual articles left-to-right, top-to-bottom".

As the quantity of information that must be covered grows rapidly, Renear says efficient strategic reading becomes increasingly critical in scientific work.

In today's electronic environment, powerful new tools are emerging that support strategic reading, allowing researchers to work with large numbers of articles simultaneously without having to read them in their entirety......... Posted by: Kevin      Read more         Source

August 16, 2009, 9:35 PM CT

Tough on stains, light on effort

Cleaning oily smears from kitchen countertops, mirrors, garage floors, and other surfaces with plain water rather than strong detergents or smelly solvents may seem like pure fantasy. But researchers in Indiana today describe what they believe to be a simple and effective state-of-the-art oil stain remover. They have developed a new coating for glass, plastics, and a range of other materials that would enable consumers to wipe away those pesky oils with plain water.

Their report at the 238th National Meeting of the American Chemical Society (ACS) points out that the same coatings can be added to common window cleaning sprays and used to prevent bathroom mirrors, automobile windshields and other surfaces from fogging up.

"You add water, and the oil just comes right off like magic," said Jeffrey Youngblood, Ph.D., lead researcher on the project. "These are eco-friendly coatings environmentally 'green' in the sense that they eliminate the need for harsh detergents and solvents in settings ranging from home kitchens to industrial machine shops that must contend with heavy oil spills".

The materials could be used in a range of consumer and industrial products, Youngblood said. They include household cleaners, easy-to-clean paints, water filters that separate water from oil, sealants for concrete floors and walls that repel oil in home garages and auto repair shops. In addition, anti-fog coatings could be used on windshields or eyewear, including everyday lenses and fog-free scuba masks......... Posted by: Kevin      Read more         Source

July 29, 2009, 11:19 PM CT

Nanotubes take flight

Rice researchers use nanomaterials to grow flying carpets, 'odako' kites.

With products that range from carpets to kites, you'd think Rice University chemist Bob Hauge was running a department store.

What he's really running is a revolution in the world of carbon nanotechnology.

In a paper published this month in Nano Research, Hauge's Rice University team describes a method for making "odako," bundles of single-walled carbon nanotubes (SWNT) named for the traditional Japanese kites they resemble. It may lead to a way to produce meter-long strands of nanotubes, which by themselves are no wider than a piece of DNA.

Hauge, a distinguished faculty fellow in chemistry at Rice's Richard E. Smalley Institute for Nanoscale Science and Technology, and his co-authors, graduate students Cary Pint and Noe Alvarez, explained the odako after which the bundles are named are gigantic kites that take a number of hands to fly, hence the a number of lines that trail from them.

In this case, the lines are nanotubes, hollow cylinders of pure carbon. Individually, they're thousands of times smaller than a living cell, but Hauge's new method creates bundles of SWNTs that are sometimes measured in centimeters, and he said the process could eventually yield tubes of unlimited length......... Posted by: Kevin      Read more         Source

July 26, 2009, 12:30 AM CT

Manipulating ripples in graphene

Graphene is nature's thinnest elastic material and displays exceptional mechanical and electronic properties. Its one-atom thickness, planar geometry, high current-carrying capacity and thermal conductivity make it ideally suited for further miniaturizing electronics through ultra-small devices and components for semiconductor circuits and computers.

But one of graphene's intrinsic features is ripples, similar to those seen on plastic wrap tightly pulled over a clamped edge. Induced by pre-existing strains in graphene, these ripples can strongly affect graphene's electronic properties, and not always favorably.

If the ripples can be controlled, however, they can be used to advantage in nanoscale devices and electronics, opening up a new arena in graphene engineering: strain-based devices.

UC Riverside's Chun Ning (Jeanie) Lau and his colleagues now report the first direct observation and controlled creation of one- and two-dimensional ripples in graphene sheets. Using simple thermal manipulation, the scientists produced the ripples, and controlled their orientation, wavelength and amplitude.

"When the graphene sheets are stretched across a pair of parallel trenches, they spontaneously form nearly periodic ripples," Lau explained. "When these sheets are heated up, they actually contract, so the ripples disappear. When they are cooled down to room temperature, the ripples re-appear, with ridges at right angle to the edges of the trenches. This phenomenon is similar to what happens to a piece of thin plastic wrap that covers a container and heated in a microwave oven."........ Posted by: Kevin      Read more         Source

July 21, 2009, 10:26 PM CT

New Blue Light Nanocrystals

Berkeley Lab scientists have produced non-toxic magnesium oxide nanocrystals that efficiently emit blue light and could also play a role in long-term storage of carbon dioxide, a potential means of tempering the effects of global warming.

In its bulk form, magnesium oxide is a cheap, white mineral used in applications ranging from insulating cables and crucibles to preventing sweaty-palmed rock climbers from losing their grip. Using an organometallic chemical synthesis route, researchers at the Molecular Foundry have created nanocrystals of magnesium oxide whose size can be adjusted within just a few nanometers. And unlike their bulk counterpart, the nanocrystals glow blue when exposed to ultraviolet light.

Current routes for generating these alkaline earth metal oxide nanocrystals require processing at high temperatures, which causes uncontrolled growth or fusing of particles to one another-not a desirable outcome when the properties you seek are size-dependent. Conversely, vapor phase techniques, which provide size precision, are time and cost intensive, and leave the nanocrystals attached to a substrate.

"We've discovered a fundamentally new, unconventional mechanism for nicely controlling the size of these nanocrystals, and realized we had an intriguing and surprising candidate for optical applications," said Delia Milliron, Facility Director of the Inorganic Nanostructures Facility at Berkeley Lab's nanoscience research center, the Molecular Foundry. "This efficient, bright blue luminescence could be an inexpensive, attractive alternative in applications such as bio-imaging or solid-state lighting"......... Posted by: Kevin      Read more         Source

June 16, 2009, 5:17 AM CT

Magnetic Superatoms

A team of Virginia Commonwealth University researchers has discovered a 'magnetic superatom' - a stable cluster of atoms that can mimic different elements of the periodic table - that one day appears to be used to create molecular electronic devices for the next generation of faster computers with larger memory storage.

The newly discovered cluster, consisting of one vanadium and eight cesium atoms, acts like a tiny magnet that can mimic a single manganese atom in magnetic strength while preferentially allowing electrons of specific spin orientation to flow through the surrounding shell of cesium atoms. The findings appear online in the journal Nature Chemistry.

Through an elaborate series of theoretical studies, Shiv N. Khanna, Ph.D., professor in the VCU Department of Physics, together with VCU postdoctoral associates J. Ulises Reveles, A.C. Reber, and graduate student P. Clayborne, and collaborators at the Naval Research Laboratory in D.C., and the Harish-Chandra Research Institute in Allahabad, India, examined the electronic and magnetic properties of clusters having one vanadium atom surrounded by multiple cesium atoms.

They observed that when the cluster had eight cesium atoms it acquired extra stability due to a filled electronic state. An atom is in a stable configuration when its outermost shell is full. Consequently, when an atom combines with other atoms, it tends to lose or gain valence electrons to acquire a stable configuration......... Posted by: Kevin      Read more         Source

June 5, 2009, 5:00 AM CT

Graphene May Have Advantages Over Copper

The unique properties of thin layers of graphite-known as graphene-make the material attractive for a wide range of potential electronic devices. Scientists have now experimentally demonstrated the potential for another graphene application: replacing copper for interconnects in future generations of integrated circuits.

In a paper reported in the June 2009 issue of the IEEE journal Electron Device Letters, scientists at the Georgia Institute of Technology report detailed analysis of resistivity in graphene nanoribbon interconnects as narrow as 18 nanometers.

The results suggest that graphene could out-perform copper for use as on-chip interconnects-tiny wires that are used to connect transistors and other devices on integrated circuits. Use of graphene for these interconnects could help extend the long run of performance improvements for silicon-based integrated circuit technology.

"As you make copper interconnects narrower and narrower, the resistivity increases as the true nanoscale properties of the material become apparent," said Raghunath Murali, a research engineer in Georgia Tech's Microelectronics Research Center and the School of Electrical and Computer Engineering. "Our experimental demonstration of graphene nanowire interconnects on the scale of 20 nanometers shows that their performance is comparable to even the most optimistic projections for copper interconnects at that scale. Under real-world conditions, our graphene interconnects probably already out-perform copper at this size scale."........ Posted by: Kevin      Read more         Source

June 5, 2009, 4:56 AM CT

Nanoscale zipper cavity

Physicists at the California Institute of Technology (Caltech) have developed a nanoscale device that can be used for force detection, optical communication, and more. The device exploits the mechanical properties of light to create an optomechanical cavity in which interactions between light and motion are greatly strengthened and enhanced. These interactions, notes Oskar Painter, associate professor of applied physics at Caltech, and the principal investigator on the research, are the largest demonstrated to date.

The device and the work that led to it are described in a recent issue of the journal Nature

The fact that photons of light, despite having no mass, nonetheless carry momentum and can interact with mechanical objects is an idea that dates back to Kepler and Newton. The mechanical properties of light are also known to limit the precision with which one can measure an object's position, since simply by using light to do the measurement, you apply a force and disturb the object.

It was important to consider these so-called back-action effects in the design of devices to measure weak, classical forces. Such considerations were part of the development of gravity-wave detectors like the Laser Interferometer Gravitational-Wave Observatory (LIGO). These sorts of interferometer-based detectors have also been used at much smaller scales, in scanning probe instruments used to detect or image atomic surfaces or even single electron spins......... Posted by: Kevin      Read more         Source

June 3, 2009, 5:10 AM CT

Control heat in large data centers

Approximately a third of the electricity consumed by large data centers doesn't power the computer servers that conduct online transactions, serve Web pages or store information. Instead, that electricity must be used for cooling the servers, a demand that continues to increase as computer processing power grows.

And the trend toward cloud computing will expand the need for both servers and cooling.

At the Georgia Institute of Technology, scientists are using a 1,100-square-foot simulated data center to optimize cooling strategies and develop new heat transfer models that can be used by the designers of future facilities and equipment. The goal is to reduce the portion of electricity used to cool data center equipment by as much as 15 percent.

"Computers convert electricity to heat as they operate," said Yogendra Joshi, a professor in Georgia Tech's Woodruff School of Mechanical Engineering. "As they switch on and off, transistors produce heat, and all of that heat must be ultimately transferred to the environment. If you are looking at a few computers, the heat produced is not that much. But data centers generate heat at the rate of tens of megawatts that must be removed".

Summaries of the research have been reported in the Journal of Electronic Packaging and International Journal of Heat and Mass Transfer and presented at the Second International Conference on Thermal Issues in Emerging Technologies, Theory and Applications. The research has been sponsored by the U.S. Office of Naval Research, and by the Consortium for Energy Efficient Thermal Management......... Posted by: Kevin      Read more         Source