Technology and Science Archive

Atom Entertainment (formerly AtomShockwave)

Part of the chart of nuclides showing the isotopes of elements that are heavier than californium (Z = 98). The number of protons (the atomic number, Z) increases along the y-axis, and the number of neutrons (N) increases along the x-axis. Element 118 is at the top right corner.

Researchers discover element 118

Oct 19, 2006 - If you think you have seen the above headline somewhere before, then you probably have. In 1999, nuclear physicists at Lawrence Berkeley National Laboratory in the US claimed to have produced three atoms of the super-heavy element with atomic number 118 -- the heaviest ever detected. But that claim was retracted three years later when it emerged that some of the data had been falsified. This time, however, element 118 -- and its slightly lighter counterpart element 116 -- is here to stay, pushing back the boundaries of the periodic table and helping researchers to understand why some nuclei are more stable than others (Phys Rev C 74 044602). The world is made up of about 90 naturally occurring elements, but since the 1940s physicists have been able to produce heavier, less stable elements. Such elements are vital for testing models of the nucleus, and to date researchers have amassed data on 29 "super-heavy" nuclei with atomic numbers between 104 and 118. The definitive discovery of element 118, which is expected to be a noble gas that lies right below radon in the periodic table, was a collaborative effort between researchers at the Livermore lab and the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. Based on data taken early last year in experiments at the JINR.

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The NIST process for "purifying" an unusual property of quantum physics called entanglement involves illuminating two pairs of beryllium ions (charged atoms) with a series of ultraviolet laser pulses. Credit: Bill Pietsch, Astronaut 3 Media Group Inc.

Physicists boost 'entanglement' of atom pairs

Oct 19, 2006 - Physicists at the Commerce Department's National Institute of Standards and Technology have taken a significant step toward transforming entanglement--an atomic-scale phenomenon described by Albert Einstein as "spooky action at a distance"--into a practical tool. They demonstrated a method for refining entangled atom pairs (a process called purification) so they can be more useful in quantum computers and communications systems, emerging technologies that exploit the unusual rules of quantum physics for pioneering applications such as "unbreakable" data encryption. The NIST work, reported in the Oct. 19, 2006, issue of Nature, marks the first time atoms have been both entangled and subsequently purified; previously, this process had been carried out only with entangled photons (particles of light). The NIST demonstration also is the first time that scientists have been able to purify particles nondestructively. Direct measurement would destroy the delicate entangled state of atom pairs; the new experiment gets around this problem by entangling two pairs of atoms and measuring only one pair. Entanglement is a curious property of quantum physics that links the condition and behavior of two or more particles, such as atoms or photons. Entanglement can occur spontaneously when two atoms interact.

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The first working "invisibility cloak"

First Demonstration of a Working Invisibility Cloak

Oct 18, 2006 - A team led by scientists at Duke University's Pratt School of Engineering has demonstrated the first working "invisibility cloak." The cloak deflects microwave beams so they flow around a "hidden" object inside with little distortion, making it appear almost as if nothing were there at all. The cloak, made with advanced 'metamaterials,' deflects microwave beams and may find a variety of wireless communications or radar applications. Cloaks that render objects essentially invisible to microwaves could have a variety of wireless communications or radar applications, according to the researchers. The team reported its findings on Thursday, Oct. 19, in Science Express, the advance online publication of the journal Science. The research was funded by the Intelligence Community Postdoctoral Fellowship Program.

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Artist's depiction of purified, electrified bacterial cell outer membrane protein binding with and passing electrons to the iron-rich mineral hematite. Credit: Pacific Northwest National Laboratory.

Biofuel Cells Without The Bio Cells

Oct 18, 2006 - Proteins keep cells humming. Some are enzymes that taxi electrons to chemicals outside the cell, to discharge excess energy generated during metabolism. This maintains energy flow in the cell and, in turn, keeps the cell alive. The process has worked a little like that slogan for a hyper-electrified desert gambling town: What happens in the cellular environs stays there. Now, scientists for the first time have observed this electricity-shuttling process taking place sans cells, in purified proteins removed from the outer membrane of the versatile, metal-altering soil bacterium Shewanella oneidensis. They suggest that proteins rendered portable from the organisms that spawned them could make miniature bioreactor cells feasible. "We show that you can directly transfer electrons to a mineral using a purified protein, and I don't think anyone had shown that before," said Thomas Squier, senior author and lab fellow at the Department of Energy's Pacific Northwest National Laboratory.

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Technicians and engineers at Northrop Grumman Space Technology in Redondo Beach, Calif., prepare the Strategic Illuminator Laser for tests. . Credit: NG.

The Most Powerful Continuously Pulsed Illuminator Laser Ever

Oct 16, 2006 - A new diode-pumped solid-state, next-generation illuminator laser developed by Northrop Grumman Corporation met all technical performance requirements recently when tests proved that it's the highest power, brightest laser of its kind ever built, according to the company. The Strategic Illuminator Laser (SILL) demonstrated multi-kilowatt-class average output power, operating at 5 kHz, with outstanding beam quality for a run time of five minutes. These achievements met all the technology goals of the SILL Phase 2 demonstration program, an effort to develop the next generation of illuminator lasers for air and space applications. The SILL program is funded by the U.S. Missile Defense Agency (MDA), Washington, D.C. "In addition to our success with SILL, Northrop Grumman has been leading the development and demonstration of complete laser systems," said Alexis Livanos, president of Northrop Grumman's Space Technology sector.

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Experiment to show the changes in the wavelength. The green light directed into the solution reappears as blue light after it has been converted. Image: Max Planck Institute for Polymer Research.

A Boost For Solar Cells With Photon Fusion

Oct 16, 2006 - Researchers at the Max Planck Institute for Polymer Research in Mainz have developed a process with which longwave light from a normal light source can be converted to shortwave light. An innovative process that converts low-energy longwave photons (light particles) into higher-energy shortwave photons has been developed by a team of researchers at the Max Planck Institute for Polymer Research in Mainz and at the Sony Materials Science Laboratory in Stuttgart. With the skillful combination of two light-active substances, the scientists have, for the first time, manipulated normal light, such as sunlight, to combine the energy in photons with particular wavelengths (Physical Review Letters, October 4, 2006). This has previously only been achieved with a similar process using high-energy density laser light. The successful outcome of this process could lay the foundation for a new generation of more efficient solar cells.

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This photo of an air bubble (black) taken just before pinch-off shows a symmetrical neck profile, which is typical of a bubble released from a carefully levelled nozzle..

Bubbles never forget

Oct 16, 2006 - Physicists at the University of Chicago have discovered that air bubbles retain a "memory" of how they are formed (Phys Rev Lett 97 144503). Their study revealed that the initial conditions of bubble formation can affect the dynamics of the singularity that occurs when a bubble pinches off a nozzle. This could have profound implications for our understanding of other phenomena that involve singularities including the formation of black holes or supernovae. A singularity occurs when one or more of the physical parameters in a system approaches infinity. In bubble formation, this occurs at the moment of pinch-off, when the stress and pressure become very large. Physicists had thought that this pinch-off would always occur in a highly symmetric manner, regardless of the initial conditions of bubble formation. But now the Chicago research group led by Sidney Nagel has used high-speed photography to reveal that the physical appearance of the singularity is influenced by the shape, size and angle of tilt of the nozzle.

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Tsu-Wei Chou, left, and Erik Thostenson of the University of Delaware have discovered a means to detect and identify damage within advanced composite materials. University of Delaware photograph by Kathy F. Atkinson.

Scientists Use Carbon Nanotube Networks To Detect Defects In Composites

Oct 06, 2006 - Two University of Delaware researchers have discovered a means to detect and identify damage within advanced composite materials by using a network of tiny carbon nanotubes, which act in much the same manner as human nerves. The discovery has important implications both in the laboratory, where the scientists hope to better predict the life span of various composite materials, and in everyday applications, where it could become an important tool in monitoring the health of composite materials used in the construction of a variety of essential products, including commercial airliners. The research is the work of Tsu-Wei Chou, Pierre S. du Pont Chair of Engineering, and Erik Thostenson, assistant professor of mechanical engineering, and will be featured in an article in the Oct. 2 issue of the influential journal Advanced Materials.

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An artists rendering of the web of entanglement between the Caesium atoms and the beam of light

Now you see it, now you don't

Oct 05, 2006 - Danish physicists have managed to light-up a cloud of atoms using light teleported from a source half a metre away. Since Charles Bennett and his team first proposed quantum teleportation in 1993, science fiction enthusiasts have had to be content with frustratingly prosaic examples of the principle. However, at the University of Copenhagen in Denmark, physicists have passed a milestone that will help to bring some practical applications of teleportation within sight (Nature 443 557). “This is the first time teleportation has been achieved between the ‘flying’ medium of light and the ‘stationary medium’ of atoms,” said Eugene Polzik of Copenhagen. “Such teleportation could serve as a main building block of a quantum network connecting distant quantum processors.” Quantum teleportation cleverly evades one of the best known peculiarities of quantum states – their inability to be measured precisely. Only some of the information of a quantum state can be learned in a single measurement, and once that measurement is made, the quantum state is effectively destroyed.

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The total bill? A cool €6.3bn, give or take the odd bottle of champagne.

Champagne moments

Oct 05, 2006 - The Large Hadron Collider could bring CERN huge rewards – but there are risks too. Anyone who is not a particle physicist is likely to look on in envy at the massive sums being spent on the Large Hadron Collider (LHC) at CERN. It has cost €1.8bn to build the machine's accelerator, which will whip protons in opposite directions around a 27 km-long underground ring before smashing them together at energies up to 14 TeV some billion times a second. The four giant detectors – including the two general-purpose experiments CMS and ATLAS – have swallowed up several more billion Euros. Then there is the new Grid computer system, which is meant to analyse the vast streams of data spewing out from thee detectors every second. The total bill? A cool €6.3bn, give or take the odd bottle of champagne. With a little over a year to go before the LHC collides its first beams together, the excitement at the Geneva lab is rising, as this special issue of Physics World reports.

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Steps in producing nanotubes from nanowires

From Nanowires to Nanotubes

Sep 28, 2006 - Hollow nanocrystals that can function as highly-efficient catalysers or transport containers for chemical agents are in great demand nowadays. Scientists from the Max Planck Institute of Microstructure Physics have created a procedure for combining chemicals to produce high quality nanotubes in large quantities. The researchers took advantage of the Kirkendall effect, which occurs during inter-diffusion between two solids. They used the effect to take nanowires of a certain chemical composition in the core and the shell, and produce nanotubes of a more complex composition. The scientists showed that this method can also be used to efficiently produce nanowires themselves (Nature Materials, August 2006). Compound nanotubes can be produced in various ways: rolling up layered materials, coating pores in templates, or eliminating the core of a core-shell nanowire.

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Illustration

Anatomy of a Discovery

Sep 26, 2006 - Some Eureka moments are more drawn out than others. For Pratik Mankidy, a Ph.D. student in the Department of Chemical Engineering at Penn State, the timeframe from "aha" to understanding took the better part of a year. "We were working with a NSF grant to develop a nanochannel reactor, a type of template for a polymeric reaction that we hoped would grow polymer nanofibers. We introduced a monomer on one side of the template, an anodized alumina membrane with thousands of pores, with the catalyst in the walls of the membrane. We hoped polymer fibers would come out the other side of the template," Mankidy says about the research project that led to his discovery. When the diameter of fibers is shrunk to the submicron or nanometer scale, the result is much superior tensile strength and a large surface to volume area ratio.

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These pseudo-3D images of the far-field polariton emission depict the stages of formation of a BEC. From left to right the EPFL team are increasing the rate of excitation power.

BECs confound at higher temperatures

Sep 28, 2006 - Two separate research groups claim to have witnessed a widespread collapse to the ground state in different quasiparticle systems, raising questions over what can really constitute a Bose--Einstein condensate. On the surface, the definition of a Bose–Einstein condensate (BEC) appears resolutely clear: when a mass of bosons is cooled below a critical temperature, there is a phase transition wherein a significant portion of the bosons collapse into the first quantum state. Therefore it might come as a little surprise to find doubt surrounding the latest two papers to demonstrate it. The first of two papers on BECs published in Nature this week describes experiments performed in France and Switzerland that created half-light, half-matter quasiparticles in a semiconductor using a focused laser (Nature 443 409). These so-called "polaritons" are bosons each made up of an electron-hole pair (itself called an "exciton") and a coupled photon.

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One of the components of MIT's micro gas-turbine engine. Credit: MIT.

Engine On A Chip Promises To Best The Battery

Sep 26, 2006 - MIT researchers are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight can, powering laptops, cell phones, radios and other electronic devices. It could also dramatically lighten the load for people who can't connect to a power grid, including soldiers who now must carry many pounds of batteries for a three-day mission -- all at a reasonable price. The researchers say that in the long term, mass-production could bring the per-unit cost of power from microengines close to that for power from today's large gas-turbine power plants. Making things tiny is all the rage. The field -- called microelectromechanical systems, or MEMS -- grew out of the computer industry's stunning success in developing and using micro technologies. "Forty years ago, a computer filled up a whole building," said Professor Alan Epstein of the Department of Aeronautics and Astronautics.

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The gray sliver reaching from top to bottom, slanted in the image, is a nanomechanical resonator, a sub-microscopic device that can vibrate like a piano string. The image was taken with a scanning electron microscope and colorized. (Courtesy Cornell University)

Physicists seek to put one thing in two places

Sep 06, 2006 - Physicists say they have made an object move just by watching it. This is inspiring them to a still bolder project: putting a small, ordinary thing into two places at once. It may be a “fantasy,” admits Keith Schwab of Cornell University in Ithaca, N.Y., one of the researchers. Then again, the first effect seemed that way not long ago, and the second is related. The research comes from the edge of quantum mechanics, the submicroscopic realm of fundamental particles. There, things behave with total disregard for our common sense. They can show signs of being in two places at once; of being both waves and particles; of taking on some characteristics only at the moment these are measured; and of acting synchronously while far apart, with no apparent way to communicate. Although these tiny building blocks of our universe do this, the relatively huge things we see every day don’t. The uncanny behavior fades the bigger a thing becomes. This is because when quantum entities are combined to make ordinary objects, the rules governing each component’s behavior add up to produce new rules.

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Billion-electron-volt, high-quality electron beams have been produced with laser wakefield acceleration

From Zero to a Billion Electron Volts in a distance of just 3.3 centimeters

Sep 25, 2006 - In a precedent-shattering demonstration of the potential of laser-wakefield acceleration, scientists at the Department of Energy's Lawrence Berkeley National Laboratory, working with colleagues at the University of Oxford, have accelerated electron beams to energies exceeding a billion electron volts (1 GeV) in a distance of just 3.3 centimeters. The researchers report their results in the October issue of Nature Physics. By comparison, SLAC, the Stanford Linear Accelerator Center, boosts electrons to 50 GeV over a distance of two miles (3.2 kilometers) with radiofrequency cavities whose accelerating electric fields are limited to about 20 million volts per meter. The electric field of a plasma wave driven by a laser pulse can reach 100 billion volts per meter, however, which has made it possible for the Berkeley Lab group and their Oxford collaborators to achieve a 50th of SLAC's beam energy in just one-100,000th of SLAC's length.

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Magnet falling

Magnet falls freely in superconducting tube

Sep 22, 2006 - A magnet will encounter no electromagnetic braking force while inside a superconducting tube, predict physicists in Brazil. This is exactly the opposite of what occurs in a popular classroom demonstration involving a tube made out of a normal conductor such as copper. Faraday’s and Lenz’s laws can be demonstrated by dropping a powerful neodynium magnet through a copper tube. The magnet takes about 25 s to fall through a two-meter-long tube -- compared to less than 1 s for a non-magnetic object. Many students are probably left wondering how the magnet would behave in a superconducting tube. Yan Levin and Felipe Rizzato at Brazil’s Federal University of Rio Grande do Sul have the answer: The magnet will fall freely as long as it is about one pipe-radius into the pipe, otherwise it does feel a force due to boundary effects (arXiv.org).

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Nanoscale metallic electrodes (in yellow) can be used to confine electrons in small regions, forming quantum dots. Credit: Luis Dias/Ohio University

Double Quantum Dots Control Kondo Effect

Sep 20, 2006 -Two quantum dots connected by wires could help scientists better control the Kondo effect in experiments, according to a study by Ohio University and University of Florida physicists published in a recent issue of Physical Review Letters. The Kondo effect occurs when electrons become trapped around the magnetic impurities in semiconductor materials, which prompts the electrons to change their spin. This phenomenon has intrigued scientists, as electronic correlations can create interesting and complex behavior in materials. In the new work, scientists demonstrate how the two quantum dot system can behave in two different and interesting ways: As a simile for a Kondo-effect system where one quantum dot is used to "filter" the effect of the current leads, and as a way to study "pseudo-gapped" systems and correlations in them, which can help scientists understand structures such as superconductors.

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University of California Santa Barbara Professor John Bowers holds a Hybrid Silicon Laser chip

Breakthrough Could Lead To Powerful, Low-Cost Chips

Sep 18, 2006 - Intel and university researchers announced Monday a breakthrough that could lead to a laser-producing chip that could vastly improve computing power at a low cost. Intel said the researchers for the company and the University of California at Santa Barbara developed a process that could allow the production of hybrid silicon-laser chips to use laser beams instead of wires to transfer data. "This breakthrough addresses one of the last major barriers to producing low-cost, high-bandwidth silicon photonics devices for use inside and around future computers and data centers," the company said in a statement. The use of photonics, or optical data transfer, could vastly increase the speed of computers while keeping costs down, the researchers said. Experts say the use of lasers could allow communication between chips within a system, bypassing many of the bottlenecks on existing computer chips.

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One striking consequence of superconductivity is the Meissner effect, in which the ability of a superconductor to expel magnetic fields from its interior is used to levitate a magnet above a superconducting disk.

Slow death for a hot topic

Sep 15, 2006 - High-temperature superconductivity could be a dead field within four years, according to a new analysis by researchers in Germany. They found that the number of papers in the field peaked in about 1990 and has been steady falling since then. By extrapolating the data, the researchers conclude that the numbers will drop to zero at some point between 2010 and 2015, provided that no roundbreaking discoveries are made in the meantime (arxiv.org). The new study was carried out by Andreas Barth from the FIZ Karlsruhe and Werner Marx from the Max Planc Institute for Solid-State Research in Stuttgart, who examined the number of papers listed in the INSPEC and Chemical Abstracts Service databases with words like "superconductivity" or "superconductor" used in the title or listed as "keywords". By plotting these as a function of time, they found that the numbers shot up rapidly in the late 1980s, following the unexpected discovery of high-temperature superconductors by Georg Bednorz and Alex M?ller at IBM's Zurich lab in 1986.

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Illustration

Bubbles collapse without weight

Sep 13, 2006 - Cavitation is an unusual process whereby tiny air bubbles grow and collapse inside water droplets. It can be a big problem in industry, where it can erode everything from ship propellors to pipelines. Now, however, researchers in Europe have obtained new insights into this process -- by studying cavitation in space. The work let them create isolated, spherical droplets of water that would be impossible to make on Earth (Phys. Rev. Lett. 97 094502). Cavitation is a problem in industry because the collapsing bubbles that form during this process focus energy to very small volumes, creating temperature "hotspots" and emitting liquid jets and shockwaves. Cavitation does, however, have a good side, being used to kill bacteria, destroy kidney stones and clean surfaces.

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File photo: Photovoltaic roof panels.

Organic Semiconductors Make Cheap And Flexible Photovoltaics And LEDs

Sep 10, 2006 - Imagine T-shirts that light up, or a beach umbrella that collects solar energy to run a portable TV. How about really cheap solar collectorsfor the roof? All this and more could come from cutting-edge research at Cornell that demonstrates a new type of organic semiconductor device which shows electroluminescence and cts as a photovoltaic cell. The device is the first to use an "ionic junction," which researchers say could lead to improved performance. Since organic semiconductors can be made in thin, flexible sheets, they could create displays on cloth or paper. "Flexible means low-cost fabrication," said George Malliaras, Cornell associate professor of materials science and engineering, in whose laboratory the research was done.

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RGB gamut

Superconducting qubits get entangled

Sep 08, 2006 - Physicists in the US have taken another step towards the dream of a quantum computer by entangling two superconducting quantum bits (or qubits) for the first time. Circuits made from superconducting elements are promising candidates for a real quantum computer because they are compatible with conventional methods for making integrated circuits (Science 313 1423). In the weird world of quantum mecahnics, particles can be "entangled" so that they have a much closer relationship than allowed by classical physics. For instance, two photons can be created in an experiment such that if one is polarized in the vertical direction, then the other is always polarized horizontally. By measuring the polarization of one of the pair, we immediately know the state of the other, no matter how far apart they are.

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The proton, one of the three main components of an atom, is known to consist of point-like particles called quarks, bound together by gluons.

New Clue To Tiniest Particles

Sep 06, 2006 - Particle physicists around the world will be designing their next generation of billion-dollar experiments following new findings from a University of Adelaide-led research team. TheHoly Grail of the world's particle physicists is to discover and describe new particles that make up the Universe's tiniest building blocks. he University of Adelaide's Associate Professor Derek Leinweber, leading a team of international theoretical physicists, has established a new approach to precision calculations on the properties of subatomic particles. The proton, one of the three main components of an atom, is known to consist of point-like particles called quarks, bound together by gluons. There are six different types of quarks and the most mysterious of these is the strange quark, which "boils up" inside the proton and then "simmers back out of existence". The new finding, published recently in the prestigious international journal Physical Review Letters, is a precise calculation of the strange quark's distribution within the proton.

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Physicists want to put this atom interferometer on a spacecraft

Atom optics moves into space

Sep 06, 2006 - Physicists are drawing up plans for a new space mission that could carry out a range of experiments in fundamental physics. The mission, which would involve placing an atom interferometer aboard a spacecraft, aims to observe the effects of quantum gravity for the first time. Other instruments will look for violations of the equivalence principle ? one of the foundations of general relativity ? as well deviations in Newtonian gravity, which would reveal the existence of higher dimensions. They could even search for hypothetical ?dark matter? particles called axions. The plans are being drawn up by Tim Sumner of Imperial College London, who intends to submit them to the European Space Agency (ESA) later this year.

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Atomic clock

NMR goes optical

Sep 05, 2006 - Physicists in the US have invented a new form of nuclear magnetic resonance (NMR) that could significantly imrove the resolution and sensitivity of the technique. The method, developed by Michael Romalis and co-workers at Princeton University, involves shining a laser on a sample and measuring how it rotates the plane of polarization of the beam. The new technique could lead to real-time two-dimensional imaging of samples, with a resolution limited only by light diffraction. Most NMR experiments involve placing a sample in a magnetic field, which encourages the spin of the nuclei to point in the same direction as the field. The frequency with which the spins wobble or "precess" about this direction provide useful information about the local molecular environment.

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Bacteria crawl clockwise in the circular groove underlying this motor. Hiratsuka et al./PNAS

Wheel of Life: Bacteria provide horsepower for tiny motor

Sep 02, 2006 - For millennia, people have hitched beasts to plows to exploit the animals' strength and energy. In a modern variant of that practice, scientists have chemically harnessed bacteria to a micromotor so that they can make the device's rotor slowly turn. The new work might lead to improved lab-on-a-chip devices and engines to propel microrobots, says Yuichi Hiratsuka, now of the University of Tokyo, who codeveloped the bacteria-powered micromotor. He and his colleagues describe the research in an upcoming Proceedings of the National Academy of Sciences. The novel micromachine "is an important step in integrating biological components into microengineered systems," comments bioengineer William O. Hancock of Pennsylvania State University in University Park. To make the motors, Hiratsuka's team, led by Taro Q.P. Uyeda of the National Institute for Advanced Industrial Science and Technology in Tsukuba, Japan, borrowed fabrication techniques from the microelectronics industry.

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Photonic crystals go magnetic

Sep 01, 2006 - Physicists in Germany have made a new type of photonic crystal by fine-tuning the magnetic, rather than the electric, properties of a material. Stefan Linden of the Karlsruhe Research Institute and colleagues at Karlsruhe University made the crystals from pairs of gold wires, which acted as artificial magnetic atoms. The discovery has opened up new ways to manipulate light on the nanoscale, the scientists claim (Phys.Rev.Lett. 97 083902). Photonic crystals are nanostructured materials in which periodic variations of some property - usually, the material's electric permittivity - produce a "photonic band gap". This affects how photons propagate through the material.

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Nanotube resonators break gigahertz barrier

Aug 31, 2006 - Physicists in the US have created nano electromechanical system resonators that achieve self-detectable mechanical resonance at frequencies greater than 1.3 GHz. Based on a carbon nanotube (CNT) structure, the devices can operate at room temperature and in air at atmospheric pressure. When taken together, these features are described as a “Holy Grail” of NEMS resonator performance (Phys.Rev.Lett 97 087203). Previous CNT resonators were limited to 200 MHz and could not operate at atmospheric pressure. Created by Alex Zettl and colleagues at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, the NEMS also proved to be very sensitive mass detectors with 10^-18g (attogram) resolution. The measurement of mass at the attogram scale was first demonstrated in 2004 by Harold Craighead and colleagues at Cornell University.

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(Artist's conception of a Quantum Interference Effect Transistor (QuIET) (IMAGE: ACS Nano Letters)

Physicists invent 'QuIET' - single molecule transistors

Aug 30, 2006 - University of Arizona physicists have discovered how to turn single molecules into working transistors. It's a breakthrough needed to make the next-generation of remarkably tiny, powerful computers that nanotechnologists dream of. They have applied for a patent on their device, called Quantum Interference Effect Transistor, nicknamed "QuIET." The American Chemical Society publication, Nano Letters, has published the researchers' article about it online. The research is planned as the cover feature in the print edition in November. A transistor is a device that switches electrical current on and off, just like a valve turns water on and off in a garden hose. Industry now uses transistors as small as 65 nanometers. The UA physicists propose making transistors as small as a single nanometer, or one billionth of a meter. "All transistors in current technology, and almost all proposed transistors, regulate current flow by raising and lowering an energy barrier," University of Arizona physicist Charles A. Stafford said.

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(Image generated by Seyet, LLC)

Nanocantilevers Yield Surprises Critical For Designing New Detectors

Aug 29, 2006 - Researchers at Purdue University have made a discovery about the behavior of tiny structures called nanocantilevers that could be crucial in designing a new class of ultra-small sensors for detecting viruses, bacteria and other pathogens. The nanocantilevers, which resemble tiny diving boards made of silicon, could be used in future detectors because they vibrate at different frequencies when contaminants stick to them, revealing the presence of dangerous substances. Because of the nanocantilever's minute size, it is more sensitive than larger devices, promising the development of advanced sensors that detect minute quantities of a contaminant to provide an early warning that a dangerous pathogen is present.

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RGB gamut

Splitting Light With Artificial Muscles Could Bring New Generation Of Color Displays

Aug 23, 2006 - Scientists have unveiled a new technology that could lead to video displays that faithfully reproduce a fuller range of colors than current models, giving such a life-like viewing experience that it could be hard to go back to your old TV. The invention, based on fine-tuning light using microscopic artificial muscles, could turn into competitively priced consumer products in eight years, the scientists say. In ordinary displays such as TV tubes, flat-screen LCDs, or plasma screens, each pixel is composed of three light-emitting elements, one for each of the fundamental colors red, green, and blue.

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Light can penetrate silver metal

See-through silver

Aug 22, 2006 - Physicists in the UK have discovered that thin films of silver -- a normally opaque material -- can be made highly transparent by sandwiching them bewteen zinc-selenide-coated glass blocks. Ian Hooper and colleagues at the University of Exeter say that the light passes through the silver a bit like the way particles can tunnel through barrriers. The work could help to improve the efficiency of organic light-emitting diodes and enable a new generation of semiconductor devices. Phys. Rev. Lett. 97 053902). It is well known that light travelling through a solid block will undergo total internal reflection if it strikes the surface at a very shallow angle. Some of the electromagnetic field, however, strays into the air -- a so-called evanescent wave.

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Artist's rendering of a smart liquid microlens

Autonomous Lenses May Bring Microworld Into Focus

Aug 15, 2006 - When Hongrui Jiang looked into a fly's eye, he saw a way to make a tiny lens so "smart" that it can adapt its focal length from minus infinity to plus infinity-without external control. Incorporating hydrogels that respond to physical, chemical or biological stimuli and actuate lens function, these liquid microlenses could advance lab-on-a-chip technologies, optical imaging, medical diagnostics and bio-optical microfluidic systems. Jiang, a University of Wisconsin-Madison assistant professor of electrical and computer engineering; David Beebe, a professor of biomedical engineering, postdoctoral researcher Liang Dong, and doctoral student Abhiskek Agarwal describe the technology in the Aug. 3 issue of the journal Nature.

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Atomic clock

Atomic clocks feel the heatsmos

Aug 11, 2006 - Temperature is not something that most people take into account when trying to find out what time it is -- unless your watch has frozen or melted that is. But in the ultra-precise world of atomic timekeeping, which governs navigation technology such as the global positioning system, the temperature is vital.Two teams of physicists in the US and Australia have now calculated the tiny shift in the atomic transition frequencies of a caesium atom, which is used to define the second, due to blackbody radiation. Although this shift has been worked out before, its value has varied by about 10% between different groups' estimates, introducing a sizeable uncertainty in the output of atomic clocks.

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James Van Allen

Astrophysicist and space pioneer dies

Aug 11, 2006 - The US astrophysicist James Van Allen died yesterday aged 91. Van Allen was best known for his studies of the Earth's magnetosphere -- the region of space filled by the Earth's magnetic field. In particular, he found bands of intense radiation, later named the Van Allen radiation belts, which he discovered using the first US satellite, Explorer 1. He also conducted the first surveys of the radiation belts of Jupiter and Saturn using the Pioneer 10 and 11 spacecraft.

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Image of a portion of the photonic crystal structure

Optical Breakthrough Makes "Lab-on-a-Chip" Possible

Aug 10, 2006 - Graphite might not sound very exciting. It’s the key ingredient in pencils, those decidedly low-tech writing devices. But graphite behaves in strange, unexplained ways when carved into sheets one atom thick, scientists have found. And they’re increasingly drawn by the possibility that such sheets might be useful in tiny electronic devices and circuits. Ultra-thin graphite sheets of this sort, called graphene, are among the hottest new materials under research, according to materials scientists. Graphene gained prominence when researchers late last year reported exotic electronic behavior in the material. The findings, from two scientific teams, appeared in the Nov. 10 issue of the research journal Nature.

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Developing Alternatives to Fossil Fuels

Aug 03, 2006 - Virginia Commonwealth University researchers have developed a new storage system to hold large quantities of hydrogen fuel that may one day power cars in a more cost-effective and consumer-friendly way. This theoretical research moves scientists another step closer in the exploration of alternative fuel sources and methods to store hydrogen fuel. “We are going to face an energy crisis at some point in the future. It’s not a question of if, but when. There is a high demand on oil, particularly due to a growing global population,” said lead author Puru Jena, Ph.D., a professor of physics at VCU.

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Superconductor reveals its true colours

Aug 03, 2006 - Physicists in the US and Japan have found strong experimental evidence that phonons -- tiny vibrations of a crystal lattice -- play a key role in high-temperature superconductivity. They believe that the phonons allow electrons with opposite spins to pair up, which is widely believed to be what happens in conventional low-temperature superconductors. Superconductivity is thought to be the result of electrons pairing up with one another to form bosons. The pairs then collapse into a single quantum state via a process called Bose-Einstein condensation and so allow electric current to flow without resistance.

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World's "bluest" sky revealed

Aug 02, 2006 - A 27-year-old TV researcher who won a competition to travel the globe in search of the world's "bluest" sky has found that Brazil is the place to be if blue is your colour. Anya Hohnbaum came to this conclusion after visiting 20 different destinations on a 72-day round-the-world trip organized by on-line travel agents Expedia. But to ensure that her findings were as scientific as possible, Hohnbaum used a special portable spectrometer that was adapted for her by scientists at the UK's National Physical Laboratory (NPL). Rio de Janeiro came top of the list, followed by New Zealand, Australia, Fiji and South Africa.

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Refining the fine-structure constant

Aug 01, 2006 - Physicists have made the most accurate measurement to date of the fine-structure constant, alpha -- the dimensionless number that is a measure of the strength of the electromagnetic force. The new value, based on the most precise measurements ever of the magnetic moment of the electron, has an uncertainty of 0.7 parts per billion. The new value is ten times better than the next most accurate way to measure alpha. Alpha -- one of the fundamental constants of physics -- determines the strength of interactions between charged particles and electromagnetic fields. It equals e²/c h-bar -- where e is the charge on the electron, h-bar is the Planck constant divided by 2π, and c is the speed of light -- and is about 1/137. As a dimensionless number, it is even more fundamental than other constants such as the strength of gravity, the speed of light or e itself.

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Tiny Chip Demonstrates Big Memory in Cosmos

Jul 27, 2006 - A chemical alloy, used in everyday electronic items such as rewritable CDs and DVDs, serves as the source of a new computer chip which researchers hope will demonstrate non-volatile memory, or information storage retention without a power source, in the radiation-hardened space environment. Debuting in 2000, the chalcogenide random access memory, or C-RAM, program, administered by the Air Force Research Laboratory's Space Vehicle Directorate, Kirtland Air Force Base, N.M., has invested in the innovative, tiny component, which features 16 times the retention capacity of the best non-volatile memory available for use in the cosmos.

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Reversing And Accelerating The Speed Of Light

Jul 25, 2006 - Physicist Costas Soukoulis and his research group at the U.S. Department of Energy's Ames Laboratory on the Iowa State University campus are having the time of their lives making light travel backwards at negative speeds that appear faster than the speed of light. That, folks, is a mind-boggling 186,000 miles per second - the speed at which electromagnetic waves can move in a vacuum. And making light seem to move faster than that and in reverse is what Soukoulis, who is also an ISU Distinguished Professor of Liberal Arts and Sciences, said is "like rewriting electromagnetism." He predicted, "Snell's law on the refraction of light is going to be different; a number of other laws will be different."

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Lowly graphite stirs new excitement

Jul 25, 2006 - Graphite might not sound very exciting. It’s the key ingredient in pencils, those decidedly low-tech writing devices. But graphite behaves in strange, unexplained ways when carved into sheets one atom thick, scientists have found. And they’re increasingly drawn by the possibility that such sheets might be useful in tiny electronic devices and circuits. Ultra-thin graphite sheets of this sort, called graphene, are among the hottest new materials under research, according to materials scientists. Graphene gained prominence when researchers late last year reported exotic electronic behavior in the material. The findings, from two scientific teams, appeared in the Nov. 10 issue of the research journal Nature.

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Laser could create dark-matter particles

Jul 25, 2006 - By the end of the year, physicists at the DESY laboratory in Germany may have caught a glimpse of an exotic dark-matter particle known as an axion. Andreas Ringwald and co-workers are planning an experiment at the lab’s FLASH free-electron laser, a device that generates extremely bright beams of high-frequency light by accelerating electrons. The researchers will try and create axions by passing the laser light through a vacuum in the presence of a magnetic field. If they succeed, it could help physicists understand dark matter, dark energy and even why matter exists in the universe at all.

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Terrific Timekeeper: Optical atomic clock beats world standard

Jul 22, 2006 - Physicists in Colorado say that they've refined an innovative atomic clock to be more precise than the breed of clocks that's been the best for 50 years. The advance indicates that the reign of atomic clocks tuned to the element cesium is coming to an end, says physicist James C. Bergquist of the National Institute of Standards and Technology (NIST) in Boulder, Colo., who led the work. To track time, a cesium clock exploits the absorption of microwaves by a cloud of cesium atoms. In contrast, the NIST optical clock makes use of interactions between ultraviolet radiation and a single mercury ion. Ultraviolet electromagnetic waves oscillate about 100,000 times as fast as the cesium-cloud microwaves do and so provide a much finer means to measure a second.

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Organic transistors act as sensors

Jul 21, 2006 - Researchers in the US have developed a new type of organic molecular transistor that can sense and respond to its chemical environment. The device, made by Colin Nuckolls at Columbia University and colleagues at the Brookhaven National Laboratory, consists of hydrocarbon molecules lying in the gap created when a single-walled carbon nanotube is cut in half. Since the electrical conductivity of the hydrocarbons changes signifcantly when the device is exposed to other molecules, the transistors can work as ultrasensitive chemical detectors (Proc. Natl. Acad. Sci. at press).

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