A Nanotechnology Consumer Products Inventory

After more than twenty years of basic and applied research, nanotechnologies are gaining in commercial use. Nanoscale materials now are in electronic, cosmetics, automotive and medical products. But it has been difficult to find out how many "nano" consumer products are on the market and which merchandise could be called "nano." While not comprehensive, this inventory gives the public the best available look at the 200+ nanotechnology-based consumer products currently on the market. Prior to this inventory, the figure most often cited by the U.S. government was that approximately 80 consumer products containing nanomaterials were being sold. Visit the site

Surfing the Web with Nothing but Brainwaves

by Chris Taylor Business 2.0 Magazine, 24 Jul 2006 Two years ago, a quadriplegic man started playing video games using his brain as a controller. That may just sound like fun and games for the unfortunate, but really, it spells the beginning of a radical change in how we interact with computers -- and business will never be the same. Someday, keyboards and computer mice will be remembered only as medieval-style torture devices for the wrists. All work -- emails, spreadsheets, and Google searches -- will be performed by mind control. Read more

Toyota Plans Hybrid That Runs on Batteries USA Today, 19 Jul 2006 by Ken Thomas Toyota sees a future in plugging in vehicles -- instead of simply pulling in for gas. Already a leader in the hybrid market with its Prius sedan, Toyota Motors plans to develop a hybrid vehicle that will run locally on batteries charged by a typical 120-volt outlet before switching over to a gasoline engine for longer hauls. The technology is far from being ready -- and there's no timeline for when such cars might be offered for sale. Still, the automaker is taking a serious look at another idea aimed at reducing motorists' dependence on gasoline: flexible fuel vehicles capable of running on E85, an alternative fuel made of 85% ethanol. Read more

Turbulent Flow Properties of Large-Scale Vortex Systems

by P. S. Bernard Proceedings of the National Academy of Sciences, 5 Jul 2006 Large-scale computations of dynamically interacting vortex tubes forming filaments are performed with a view toward investigating their relationship to turbulent fluid flow. It is shown that the statistical properties of the tubes are consistent with commonly accepted observations about turbulence such as the Kolmogorov inertial range spectrum and lognormality of the vorticity distribution. A loop-removal algorithm is demonstrated to reduce the nominally exponential growth rate in the number of tubes to linear growth without apparent harm to the underlying physics. In this form, a vortex tube method may become a practical means for simulating high Reynolds number turbulent flows. Read more

Electric and Photoelectric Gates for Ion Feedback Suppression in Multi-GEM Structures

by A. Buzulutskov & A. Bondar arXiv.org E-print Archive, 5 Jul 2006 A new approach to suppress ion feedback in multi-GEM structures is suggested. In this approach, a potential difference applied across the gap between two adjacent GEMs has the opposite polarity compared to the standard configuration. In such a gap structure, called Electric Gate, the signal transfer from the first to second GEM is presumably provided by electric field lines still existing between the holes of the two GEMs at lower gate voltages. On the other hand, ion feedback between the GEMs turned out to be substantially reduced. We also consider another configuration, called Photoelectric Gate, in which in addition to the Electric Gate configuration, a CsI photocathode is deposited on the second GEM. In Photoelectric Gate, ion feedback through the gap is fully suppressed and the signal transfer through the gap is provided by photoelectric mechanism due to either avalanche scintillations in the first GEM or proportional scintillations in the electroluminescence gap replacing the first GEM. The suggested techniques of ion feedback suppression might find applications in the field of TPC detectors, gas photomultipliers and two-phase avalanche detectors. Read more

Hybrid Quantum Repeater Using Bright Coherent Light

by P. van Loock et al. Physical Review Letters, 19 June 2006 We describe a quantum repeater protocol for long-distance quantum communication. In this scheme, entanglement is created between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and distributing the outgoing bright coherent-light pulses among the stations. Noisy entangled pairs of electronic spin are then prepared with high success probability via homodyne detection and postselection. The local gates for entanglement purification and swapping are deterministic and measurement-free, based upon the same coherent-light resources and weak interactions as for the initial entanglement distribution. Finally, the entanglement is stored in a nuclear-spin-based quantum memory. With our system, qubit-communication rates approaching 100 Hz over 1280 km with fidelities near 99% are possible for reasonable local gate errors. Read more

Wireless Sensors Could Protect U.S. Power Grid

by Tom Simonite NewScientist.com, 4 Jul 2006 A network of compact surveillance sensors could soon be monitoring the U.S. power grid. Sensors attached to electricity pylons would spot problems like bad weather or damage caused by terrorist attacks and automatically re-route around trouble spots. Electricity companies already measure the load on power lines to spot problems and divert power around them. But the wireless sensor network under development at Iowa State University will provide firms with much more detailed information. Read more

Carbon Sheet Solutions

Nature, 20 Jul 2006 by Nicholas A. Kotov Carbon nanotubes have revolutionized materials science, with their combination of exceptional mechanical strength and unique electrical properties. The media has added to the hype, by enthusing over the way this new form of carbon will transform the transport and electronics industries. Yet many problems still need to be solved before carbon nanotubes can be successfully incorporated into composite materials. The three biggest issues are the fact that nanotubes tend to clump together during processing, the difficulty of controlling their diameter and the way the carbon sheet is rolled, and the high cost of their production. Read more

Electronic Control of Friction in Silicon pn Junctions

by Jeong Young Park et al. Science, 14 Jul 2006 A remarkable dependence of the friction force on carrier concentration was found on doped silicon substrates. The sample was a nearly intrinsic n-type Si(100) wafer patterned with 2-micrometer-wide stripes of highly B-doped p-type material. The counter surface was the tip of an atomic force microscope coated with conductive titanium nitride. The local carrier concentration was controlled through application of forward or reverse bias voltages between the tip and the sample in the p and the n regions. Charge depletion or accumulation resulted in substantial differences in friction force. The results demonstrate the capability to electronically control friction in semiconductor devices, with potential applications in nanoscale machines containing moving parts. Read more

Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts

by Anisoara Socoliuc et al. Science, 14 Jul 2006 Stiction and wear are demanding problems in nanoelectromechanical devices, because of their large surface-to-volume ratios and the inapplicability of traditional liquid lubricants. An efficient way to switch friction on and off at the atomic scale is achieved by exciting the mechanical resonances of the sliding system perpendicular to the contact plane. The resulting variations of the interaction energy reduce friction below 10 piconewtons in a finite range of excitation and load, without any noticeable wear. Without actuation, atomic stick-slip motion, which leads to dissipation, is observed in the same range. Even if the normal oscillations require energy to actuate, our technique represents a valuable way to minimize energy dissipation in nanocontacts. Read more

Nanotube micro-optomechanical actuators

by Shaoxin Lu & Balaji Panchapakesan Applied Physics Letters, 19 Jun 2006 In this letter we demonstrate a simple carbon nanotube patterning technique that combines nanotube film bonding, photolithography, and O₂ plasma etching. Well defined carbon nanotube film structures with line widths less than ~1.5 µm and thickness ranging from 40 to 780 nm were readily fabricated. A micro-optomechanical actuator based on this process has been demonstrated. This patterning process can be utilized for the integration of nanomaterials for wide variety of devices including microeletromechanical systems, field emission displays, and micro-optomechanical systems. Read more

Symmetry breaking in individual plasmonic nanoparticles

by Hui Wang et al. Proceedings of the National Academy of Sciences, 18 Jul 2006 The plasmon resonances of a concentric metallic nanoshell arise from the hybridization of primitive plasmon modes of the same angular momentum on its inner and outer surfaces. For a nanoshell with an offset core, the reduction in symmetry relaxes these selection rules, allowing for an admixture of dipolar components in all plasmon modes of the particle. This metallodielectric nanostructure with reduced symmetry exhibits a core offset-dependent multipeaked spectrum, seen in single-particle spectroscopic measurements, and exhibits significantly larger local-field enhancements on its external surface than the equivalent concentric spherical nanostructure. Read more

Dynamic Packet Aggregation to Solve Performance Anomaly in 802.11 Wireless Networks

by Tahiry Razafindralambo et al. arXiv.org E-print Archive, 20 Jul 2006 In the widely used 802.11 standard, the so called performance anomaly is a well known issue. Several works have tried to solve this problem by introducing mechanisms such as packet fragmentation, backoff adaptation, or packet aggregation during a fixed time interval. In this paper, we propose a novel approach solving the performance anomaly problem by packet aggregation using a dynamic time interval, which depends on the busy time of the wireless medium. Our solution differs from other proposition in the literature because of this dynamic time interval, which allows increasing fairness, reactivity, and in some cases efficiency. In this article, we emphasize the performance evaluation of our proposal. Read more

High-Speed Strained-Single-Crystal-Silicon Thin-Film Transistors on Flexible Polymers

by Hao-Chih Yuan et al. Journal of Applied Physics, 14 Jul 2006 (online) We fabricate thin-film transistors (TFTs) on both strained and unstrained single-crystal Si membranes transferred to flexible-polymer substrates. The active layer is transferred from the starting silicon on insulator (SOI) using a simple, fast, and reliable dry-printing method. When a multilayer Si/SiGe/Si structure is pseudomorphically grown on SOI and the buried oxide is selectively removed, strained Si with a negligible density of dislocations is achieved via elastic strain sharing between the SiGe alloy layer and the Si layers. Both the drain current and the transconductance of TFTs fabricated on this strained Si/SiGe/Si membrane after its transfer to the flexible polymer are much higher than of TFTs fabricated on the unstrained-Si counterpart. Read more

Universally Programmable Quantum Cellular Automaton

by D. J. Shepherd, T. Franz, & R. F. Werner Physical Review Letters, 13 Jul 2006 We discuss the role of classical control in the context of reversible quantum cellular automata. Employing the structure theorem for quantum cellular automata, we give a general construction scheme to turn an arbitrary cellular automaton with external classical control into an autonomous one, thereby proving the computational equivalence of these two models. We use this technique to construct a universally programmable cellular automaton on a one-dimensional lattice with single cell dimension. Read more

Graphene-Based Composite Materials

by Sasha Stankovich et al. Nature, 20 Jul 2006) Graphene sheets -- one-atom-thick two-dimensional layers of sp²-bonded carbon -- are predicted to have a range of unusual properties. Their thermal conductivity and mechanical stiffness may rival the remarkable in-plane values for graphite; their fracture strength should be comparable to that of carbon nanotubes for similar types of defects; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties. One possible route to harnessing these properties for applications would be to incorporate graphene sheets in a composite material. The manufacturing of such composites requires not only that graphene sheets be produced on a sufficient scale but that they also be incorporated, and homogeneously distributed, into various matrices. Graphite, inexpensive and available in large quantity, unfortunately does not readily exfoliate to yield individual graphene sheets. Here we present a general approach for the preparation of graphene-polymer composites via complete exfoliation of graphite and molecular-level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene-graphene composite formed by this route exhibits a percolation threshold of approx0.1 volume per cent for room-temperature electrical conductivity, the lowest reported value for any carbon-based composite except for those involving carbon nanotubes; at only 1 volume per cent, this composite has a conductivity of approx0.1 S m^-1, sufficient for many electrical applications. Our bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications. Read more

First Direct Observations of Spinons and Holons

DOE/Lawrence Berkeley National Laboratory Press Release, 13 Jul 2006 The theory has been around for more than 40 years, but only now has it been confirmed through direct and unambiguous experimental results. Working at the Advanced Light Source of the Department of Energy's Lawrence Berkeley National Laboratory, a team of researchers has observed the theoretical prediction of electron "spin-charge separation" in a one-dimensional solid. These results hold implications for future developments in several key areas of advanced technology, including high-temperature superconductors, nanowires and spintronics. Read more

MIT Creates Fiber Webs That See

Massachusetts Institute of Technology Press Release, 17 Jul 2006 In a radical departure from conventional lens-based optics, MIT scientists have developed a sophisticated optical system made of mesh-like webs of light-detecting fibers. The fiber constructs, which have a number of advantages over their lens-based predecessors, are currently capable of measuring the direction, intensity and phase of light without the lenses, filters or detector arrays that are the classic elements of optical systems such as eyes or cameras. Ultimately the researchers expect the new system will be capable of much more, with potential applications ranging from improved space telescopes to clothing that provides situational awareness to soldiers or even the visually impaired. Read more

Neural Networks with Complex and Quaternion Inputs

by Adityan Rishiyur arXiv.org E-print Archive, 18 Jul 2006 This article investigates Kak neural networks, which can be instantaneously trained, for complex and quaternion inputs. The performance of the basic algorithm has been analyzed and shown how it provides a plausible model of human perception and understanding of images. The motivation for studying quaternion inputs is their use in representing spatial rotations that find applications in computer graphics, robotics, global navigation, computer vision and the spatial orientation of instruments. The problem of efficient mapping of data in quaternion neural networks is examined. Some problems that need to be addressed before quaternion neural networks find applications are identified. Read more

Determination of Accurate Microstructures Using X-Rays

by Sang-Wook Han SPIE Newsroom, accessed 20 Jul 2006 Materials have specific intrinsic properties, such as conductivity, magnetization, chemical potential, etc. These physical and chemical properties are mainly determined by the constituent elements of the material and the nature of their bonding. For example, diamond and graphite both consist of the same element (carbon), but their properties are quite distinct. Hence, to understand the properties of matter, structural determination is required. Read more

Self-Assembled Templates Guide Growth of Nanostructures on a Silicon Substrate

by James Owen SPIE Newsroom, accessed 20 Jul 2006 To build next-generation nanoelectronic devices -- composed of switchable molecules, carbon nanotubes, and so on -- arranging and interconnecting the nanoscale components creates a significant challenge. The problem arises when trying to fabricate features just a few nanometers wide across an entire device. Conventional or top-down lithographic techniques are reaching their limits at 65nm. Direct-writing techniques, such as electron-beam and scanning-probe-microscope lithography, can theoretically write lines one-atom wide, but these techniques do not scale up to patterning across an entire substrate, such as silicon. To address these issues, many bottom-up techniques based upon the assembly of nanostructures are currently being developed. Read more

Deformation of Nanostructured Materials

by Ruth Schwaiger SPIE Newsroom, accessed 20 Jul 2006 Increased interest in nanoscale deformation has been spurred by the rapid miniaturization of features and components in microelectronic devices, magnetic storage media, and micro- and nanoelectromechanical systems. Materials for these applications are often chosen because of their electronic, optical, or magnetic properties. Frequently, however, the mechanical properties are the performance-limiting factor. Until recently, the techniques used to produce samples resulted in a high number of induced artefacts and, hence, irregular mechanical properties. Thanks to progress in processing methods, we can now make nanograin samples of high purity and high density that, under experimental conditions, show reproducible characteristics. Such fully dense materials are excellent candidates for fundamental mechanical property studies as well as for high-performance applications. Read more

Heart of a New Machine

by Kim Krieger IEEE Spectrum, July 2006 The little robot's big round eyes glow a happy green, and its antennae lean forward. "Hello, I'm Quasi!" it chirps to a small crowd at an exhibition held this past fall at Carnegie Mellon University, in Pittsburgh. "What's your name?" While most robots are designed to serve a single dull, utilitarian function, Quasi's reason for being is charm. The machine's creators, all graduate students at Carnegie Mellon's Entertainment Technology Center, wanted to build a captivating character that would go well beyond the standard animatronic amusement park figures that spew out canned patter to bored preschoolers. They wanted to build a robot that would make people forget it's a robot. Read more

Metcalfe's Law Is Wrong

by Bob Briscoe, Andrew Odlyzko, & Benjamin Tilly IEEE Spectrum, July 2006 Of all the popular ideas of the Internet boom, one of the most dangerously influential was Metcalfe's Law. Simply put, it says that the value of a communications network is proportional to the square of the number of its users. The law is said to be true for any type of communications network, whether it involves telephones, computers, or users of the World Wide Web. While the notion of "value" is inevitably somewhat vague, the idea is that a network is more valuable the more people you can call or write to or the more Web pages you can link to. Remarkably enough, though the quaint nostrums of the dot-com era are gone, Metcalfe's Law remains, adding a touch of scientific respectability to a new wave of investment that is being contemplated. That's dangerous because, as we will demonstrate, the law is wrong. Read more

Old World, New Grid

by Fabrizio Gagliardi & Francois Grey IEEE Spectrum, July 2006 Sometime next year the largest scientific instrument ever built will come to life in an underground complex in Switzerland. The Large Hadron Collider will send two beams of protons in opposite directions around a 27-kilometer-long circular tunnel. The beams will collide head-on, producing a shower of subatomic fragments that scientists expect will include exotic, never-before-seen particles that could change our fundamental knowledge of the universe. Researchers at the European Organization for Nuclear Research know that spotting the elusive bits of matter they are looking for will be a daunting task. They will have to sift through a colossal haystack of collision data: some 15 million gigabytes a year. Their solution? A vast collection of high-powered computer systems scattered in nearly 200 research centers around the world, networked and configured to function as a single parallel processing system. Read more

Attention Turns to RF and Microwave Test and Measurement

by Courtney E. Howard Military & Aerospace Electronics, July 2006 Doubtless, it is important to ensure the accuracy, availability, and reliability of virtually all electronic systems employed in military, avionics, and aerospace applications, yet few are more critical than radio-frequency and microwave solutions. Read more

European Research Team Strives to Make Robotic Systems More Decisive

Max-Planck-Gesellschaft Press Release, 14 Jul 2006 We are sitting in a soccer stadium and discover our neighbor sitting in the 10th row. We recognize him with no difficulty at all, even though he is wearing sunglasses and a cap in his club colors. Complex recognition processes like this work because the brain, sensory organs and nerve pathways are able to pick up stimuli and process them. The ability to classify things appears to be a fundamental characteristic of human intelligence, and one that gives robots a real "headache." In situations in which a robot has no access to knowledge of a pre-defined environment, and pre-programmed control is therefore not possible, the robot will tend to fail miserably in its task. But it is precisely autonomous robots capable of acting in response to a given situation that could be of great use to humans. Read more

Ultrasensitive Solution-Cast Quantum Dot Photodetectors

by Gerasimos Konstantatos et al. Nature, 13 Jul 2006 Solution-processed electronic and optoelectronic devices offer low cost, large device area, physical flexibility and convenient materials integration compared to conventional epitaxially grown, lattice-matched, crystalline semiconductor devices. Although the electronic or optoelectronic performance of these solution-processed devices is typically inferior to that of those fabricated by conventional routes, this can be tolerated for some applications in view of the other benefits. We report the fabrication of solution-processed infrared photodetectors that are superior in their normalized detectivity (D*, the figure of merit for detector sensitivity) to the best epitaxially grown devices operating at room temperature. We produced the devices in a single solution-processing step, overcoating a prefabricated planar electrode array with an unpatterned layer of PbS colloidal quantum dot nanocrystals. The devices showed large photoconductive gains with responsivities greater than 10³ A W^-1. The best devices exhibited a normalized detectivity D* of 1.8 times 10¹³ jones (1 jones = 1 cm Hz^1/2 W^-1) at 1.3 microm at room temperature: today's highest performance infrared photodetectors are photovoltaic devices made from epitaxially grown InGaAs that exhibit peak D* in the 10¹² jones range at room temperature, whereas the previous record for D* from a photoconductive detector lies at 10¹¹ jones. The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices. Read more

Electronic Control of Friction in Silicon pn Junctions

by Jeong Young Park et al. Science, 14 Jul 2006 A remarkable dependence of the friction force on carrier concentration was found on doped silicon substrates. The sample was a nearly intrinsic n-type Si(100) wafer patterned with 2-micrometer-wide stripes of highly B-doped p-type material. The counter surface was the tip of an atomic force microscope coated with conductive titanium nitride. The local carrier concentration was controlled through application of forward or reverse bias voltages between the tip and the sample in the p and the n regions. Charge depletion or accumulation resulted in substantial differences in friction force. The results demonstrate the capability to electronically control friction in semiconductor devices, with potential applications in nanoscale machines containing moving parts. Read more

Suprising Discovery May Lead to New Understanding of Water Quality

DOE/Argonne National Laboratory Press Release, 11 Jul 2006 Scientists at the U.S. Department of Energy's Argonne National Laboratory have discovered new ways that ions interact with mineral surfaces in water, opening a door to new knowledge on how contaminants travel in the environment. The insight, leads to a better understanding of the factors that determine water quality. Read more

New Model of Internet Topology Using k-shell Decomposition

by Shai Carmi et al. arXiv.org E-print Archive, 17 Jul 2006 We introduce and use k-shell decomposition to investigate the topology of the Internet at the AS level. Our analysis separates the Internet into three sub-components: (a) a nucleus which is a small (~100 nodes) very well connected globally distributed subgraph; (b) a fractal sub-component that is able to connect the bulk of the Internet without congesting the nucleus, with self similar properties and critical exponents; and (c) dendrite-like structures, usually isolated nodes that are connected to the rest of the network through the nucleus only. This unique decomposition is robust, and provides insight into the underlying structure of the Internet and its functional consequences. Our approach is general and useful also when studying other complex networks. Read more

Scientists to Build 'Brain Box'

BBC News, 17 Jul 2006 A new type of computer that mimics the complex interactions in the human brain is being built by U.K. scientists. The £1m machine, nicknamed the "brain box", will be constructed at the University of Manchester. The first of its kind in the world, it will be used to help researchers engineer fail-safe electronics. Read more

Plastic Planes Set to Rule Sky

BBC News, 16 Jul 2006 Britons travelling abroad are likely to be flying in plastic planes in the future, says the chief of Boeing. All 737 planes will be made from non-metal materials, or composites, because they do not corrode, said president Alan Mulally. Read more

An Atom-Sorting Machine

by Yevhen Miroshnychenko et al. Nature, 13 Jul 2006 Laser cooling and trapping techniques allow us to control and manipulate neutral atoms. Here we rearrange, with submicrometre precision, the positions and ordering of laser-trapped atoms within strings by manipulating individual atoms with optical tweezers. Strings of equidistant atoms created in this way could serve as a scalable memory for quantum information. Read more

Converting Thoughts into Action

by Stephen H. Scott Nature, 13 Jul 2006 There is a clear need to help people who have brain or spinal-cord damage to communicate and interact with the outside world. Progress to that end is being made with brain-implantation technology. Read more

A High-Performance Brain–Computer Interface

by Gopal Santhanam et al. Nature, 13 Jul 2006 Recent studies have demonstrated that monkeys and humans can use signals from the brain to guide computer cursors. Brain-computer interfaces (BCIs) may one day assist patients suffering from neurological injury or disease, but relatively low system performance remains a major obstacle. In fact, the speed and accuracy with which keys can be selected using BCIs is still far lower than for systems relying on eye movements. This is true whether BCIs use recordings from populations of individual neurons using invasive electrode techniques or electroencephalogram recordings using less- or non-invasive techniques. Here we present the design and demonstration, using electrode arrays implanted in monkey dorsal premotor cortex, of a manyfold higher performance BCI than previously reported. These results indicate that a fast and accurate key selection system, capable of operating with a range of keyboard sizes, is possible (up to 6.5 bits per second, or approximately 15 words per minute, with 96 electrodes). The highest information throughput is achieved with unprecedentedly brief neural recordings, even as recording quality degrades over time. These performance results and their implications for system design should substantially increase the clinical viability of BCIs in humans. Read more

Neuronal Ensemble Control of Prosthetic Devices by a Human with Tetraplegia

by Leigh R. Hochberg et al. Nature, 13 Jul 2006 Neuromotor prostheses (NMPs) aim to replace or restore lost motor functions in paralysed humans by routeing movement-related signals from the brain, around damaged parts of the nervous system, to external effectors. To translate preclinical results from intact animals to a clinically useful NMP, movement signals must persist in cortex after spinal cord injury and be engaged by movement intent when sensory inputs and limb movement are long absent. Furthermore, NMPs would require that intention-driven neuronal activity be converted into a control signal that enables useful tasks. Here we show initial results for a tetraplegic human (MN) using a pilot NMP. Neuronal ensemble activity recorded through a 96-microelectrode array implanted in primary motor cortex demonstrated that intended hand motion modulates cortical spiking patterns three years after spinal cord injury. Decoders were created, providing a 'neural cursor' with which MN opened simulated e-mail and operated devices such as a television, even while conversing. Furthermore, MN used neural control to open and close a prosthetic hand, and perform rudimentary actions with a multi-jointed robotic arm. These early results suggest that NMPs based upon intracortical neuronal ensemble spiking activity could provide a valuable new neurotechnology to restore independence for humans with paralysis. Read more

In Search of the Sixth Sense

Nature, 13 Jul 2006 by Alison Abbott Implants in the brain could one day help paralysed people move robotic arms and legs. But first, scientists need to work out how our brains know where our limbs are. Read more

HP Develops Tiny Radio Chips

by John Markoff New York Times, 17 Jul 2006 HP researchers based in England have developed very small chips that can store 512,000 bytes of information and be read by a handheld device. The chips, called Memory Spots, are 1.4 square millimeters and feature small processors, which would allow the chips to actively protect the data they contain. Unlike RFID tags, which company officials said the new chips are not intended to replace, the chips hold significantly more data and cannot be read from several feet away. Whereas RFID chips are designed for inventory and supply-chain applications, Memory Spots have different potential. Because the HP chips have a relatively large capacity, they can store not only text-based information but also audio, video, or images. HP officials said the chips might be used in medical bracelets, for example, or attached to photos to store information about the pictures. Read more

Dyson Announces School to Promote Engineering

BBC News, 10 Jul 2006 British inventor and entrepreneur James Dyson has announced plans to start a new school for students between the ages of 14 and 18 to promote the study of engineering. According to Dyson, British schools do not provide sufficient instruction in engineering to students who want to study it. As a result, he said, the country stands to lose out to nations including China and India in science and engineering. The Dyson School of Design Innovation in Bath would cost an estimated 22 million pounds, of which half would come from the Dyson Foundation and half from the British government. The school would also enjoy the support of several leading engineering firms -- Airbus, Rolls-Royce, and Williams Racing, a Formula One team. Engineers from these companies would visit the school and speak to students, who would in turn be allowed to visit the companies' offices. Read more

Glass Seals Promise Image Sensor Yield Boosts

by David Bursky EE Times, 13 Jul 2006 As image sensor resolution increases and pixel sizes decrease, the sensor production yields become more sensitive to particulates -- material particles that end up dropping onto the surface of the sensor. Read more

Georgia Tech Preps Personal Robots for Computer Science Students

by Patrick Mannion EE Times, 13 Jul 2006 A new academic group at Georgia Institute of Technology will design personal robots for use in education, claiming that robotics is about to enter the equivalent of the PC era in computing. The effort is partly motivated by a desire to address a nationwide downturn in computer science enrollment. Read more

Army Enlists Nanotechnology for Vehicle Armor

by George Leopold EE Times, 11 Jul 2006 The U.S. Army has for months been searching for ways to improve armor on vehicles that have been a prime target for improvised explosives and roadside bombs in Iraq and Afghanistan. A requirement for lightweight ground vehicles is the ability to join different materials when adding armor. The Army has launched a research effort under its small business innovation program to find new ways to join different materials. One approach is called nanofoil. Read more

Understanding the Internet Topology Evolution Dynamics

by Shi Zhou arXiv.org E-print Archive, 13 Jul 2006 The internet structure is extremely complex. The Positive-Feedback Preference (PFP) model is a recently introduced internet topology generator. The model uses two generic algorithms to replicate the evolution dynamics observed on the internet historic data. The phenomenological model was originally designed to match only two topology properties of the internet, i.e. the rich-club connectivity and the exact form of degree distribution. Whereas numerical evaluation has shown that the PFP model accurately reproduces a large set of other nontrivial characteristics as well. This paper aims to investigate why and how this generative model captures so many diverse properties of the internet. Based on comprehensive simulation results, the paper presents a detailed analysis on the exact origin of each of the topology properties produced by the model. This work reveals how network evolution mechanisms control the obtained topology properties and it also provides insights on correlations between various structural characteristics of complex networks. Read more

Circle Formation of Weak Mobile Robots

by Yoann Dieudonne, Ouiddad Labbani-Igbida, & Franck Pet arXiv.org E-print Archive, 12 Jul 2006 The contribution is twofold. We first show the validity of the conjecture of D´efago and Konagaya, i.e., there exists no deterministic oblivious algorithm solving the Uniform Transformation Problem for any number of robots. Next, a protocol which solves deterministically the Circle Formation Problem in finite time for any number n of weak robots -- n /∈ {4, 6, 8} -- is proposed. The robots are assumed to be uniform, anonymous, oblivious, and they share no kind of coordinate system nor common sense of direction. Read more

Characterization of CDMA Communication by Eigenvalue Spectrum

by Koujin Takeda, Shinsuke Uda, & Yoshiyuki Kabashima arXiv.org E-print Archive, 11 Jul 2006 An approach by which to analyze the performance of the code division multiple access (CDMA) scheme, which is a core technology used in modern wireless communication systems, is provided. The approach characterizes the objective system by the eigenvalue spectrum of a cross-correlation matrix composed of signature sequences used in CDMA communication, which enables us to handle a wider class of CDMA systems beyond the basic model reported by Tanaka. The utility of the novel scheme is shown by analyzing a system in which the generation of signature sequences is designed for enhancing the orthogonality. Read more

'Magnetic Memory' Chip Unveiled

BBC News, 10 Jul 2006 A microchip which can store information like a hard drive has been unveiled by U.S. company Freescale. The chip, called magnetoresistive random-access memory, maintains data by relying on magnetic properties rather than an electrical charge. Read more

Surface Crystallization in a Liquid AuSi Alloy

by Oleg G. Shpyrko et al. Science, 7 Jul 2006 X-ray measurements reveal a crystalline monolayer at the surface of the eutectic liquid Au₈₂Si₁₈, at temperatures above the alloy's melting point. Surface-induced atomic layering, the hallmark of liquid metals, is also found below the crystalline monolayer. The layering depth, however, is threefold greater than that of all liquid metals studied to date. The crystallinity of the surface monolayer is notable, considering that AuSi does not form stable bulk crystalline phases at any concentration and temperature and that no crystalline surface phase has been detected thus far in any pure liquid metal or nondilute alloy. These results are discussed in relation to recently suggested models of amorphous alloys. Read more

Seeking Room-Temperature Ferromagnetic Semiconductors

by Koji Ando Science, 30 Jun 2006 Microelectronic circuits that retain their logic state when the power is off would permit entirely new kinds of computers. Ferromagnetic semiconductors might make this technology possible. Read more

Bio-Inspired Fabrication of Flexible Ceramics

by Naoto Shirahata SPIE Newsroom, accessed 7 Jul 2006 The microfabrication of optoelectronic components that are made of ceramic and attached to a mechanically flexible polymer sheet, has recently attracted attention. This is due to their varied practical applications including flexible flat panel and wearable displays, radio-frequency identification tags, and electronic papers. Such high-technology potential is attributed to polymers' distinctive properties such as flexibility, light weight, ease of design and coloring, and low cost. Read more

Layer-by-Layer Assembled Nanocontainers for Self-Healing Corrosion Protection

by D. G. Shchukin Advanced Materials, 27 Jun 2006 Planes, trains, and automobiles could one day last a whole lot longer thanks to a smart coating that stops rust in its tracks. The material reacts to damage by releasing a substance that blocks corrosion then reseals the breach. Today, metals are protected from rusting either by galvanising them with a thin layer of zinc, or by applying a waterproof polymer film. But these only stop corrosion if their surface remains pristine. The moment it is punctured, moist air or water can get in and do its worst to the naked metal underneath. Now Helmut Möhwald and colleagues at the Max Planck Institute for Colloids and Interfaces in Potsdam, Germany, have designed a coating that not only acts as a moisture barrier but also copes with cracks and scratches. Read more

Phase Modifiers Promote Efficient Production of Hydroxymethylfurfural from Fructose

Science, 30 Jun 2006 by Yuriy Román-Leshkov, Juben N. Chheda, & James A. Dumesic Furan derivatives obtained from renewable biomass resources have the potential to serve as substitutes for the petroleum-based building blocks that are currently used in the production of plastics and fine chemicals. We developed a process for the selective dehydration of fructose to 5-hydroxymethylfurfural (HMF) that operates at high fructose concentrations (10 to 50 weight %), achieves high yields (80% HMF selectivity at 90% fructose conversion), and delivers HMF in a separation-friendly solvent. In a two-phase reactor system, fructose is dehydrated in the aqueous phase with the use of an acid catalyst (hydrochloric acid or an acidic ion-exchange resin) with dimethylsulfoxide and/or poly(1-vinyl-2-pyrrolidinone) added to suppress undesired side reactions. The HMF product is continuously extracted into an organic phase (methylisobutylketone) modified with 2-butanol to enhance partitioning from the reactive aqueous solution. Read more

I Robot, Your Companion

IST Results Press Release, 29 Jun 2006 The concept of a cognitive robotic companion inspires some of the best science fiction but one day may be science fact following the work of the four-year COGNIRON project funded since January 2004 by the IST's Future and Emerging Technologies initiative. But what could a cognitive robot companion do? "The example that's often used is a robot that's able to fulfil your needs, like passing you a drink or helping in everyday tasks," says Dr Raja Chatila, project coordinator. "That might seem a bit trivial, but let me ask you a question: In the 1970s, what was the use of a personal computer?" he asks. It's a good point. In fact, it was then impossible to imagine how PCs would change the world's economics, politics and society in just 30 years. The eventual uses, once the technology developed, were far from trivial. Read more

Resonance in the Electron-Doped High-Transition-Temperature Superconductor Pr0.88LaCe0.12CuO4-

by Stephen D. Wilson Nature, 6 July 2006 In conventional superconductors, the interaction that pairs the electrons to form the superconducting state is mediated by lattice vibrations (phonons). In high-transition-temperature (high-Tc) copper oxides, it is generally believed that magnetic excitations might play a fundamental role in the superconducting mechanism because superconductivity occurs when mobile ‘electrons’ or ‘holes’ are doped into the antiferromagnetic parent compounds. Indeed, a sharp magnetic excitation termed ‘resonance’ has been observed by neutron scattering in a number of hole-doped materials. The resonance is intimately related to superconductivity, and its interaction with charged quasi-particles observed by photoemission, optical conductivity, and tunnelling suggests that it might play a part similar to that of phonons in conventional superconductors. The relevance of the resonance to high-Tc superconductivity, however, has been in doubt because so far it has been found only in hole-doped materials. Here we report the discovery of the resonance in electron-doped superconducting Pr_0.88LaCe_0.12CuO4- (T_c = 24 K). We find that the resonance energy (Er) is proportional to Tc via E_r 5.8k_BT_c for all high-Tc superconductors irrespective of electron- or hole-doping. Our results demonstrate that the resonance is a fundamental property of the superconducting copper oxides and therefore must be essential in the mechanism of superconductivity. Read more

Increased Osteoblast and Decreased Staphylococcus Epidermidis Functions on Nanophase ZnO and TiO2

by Gabriel Colon, Brian C. Ward, & Thomas J. Webster Journal of Biomedical Materials Research - Part A, 2 Jun 2006 Many engineers and surgeons trace implant failure to poor osseointegration and/or bacteria infection. By using novel nanotopographies, researchers have shown that nanostructured ceramics, carbon fibers, polymers, metals, and composites enhance osteoblast adhesion and calcium/phosphate mineral deposition. However, the function of bacteria on materials with nanostructured surfaces remains largely uninvestigated. This is despite the fact that during normal surgical insertion of an orthopedic implant, bacteria from the patient's own skin and/or mucosa enters the wound site. These bacteria irreversibly adhere to an implant surface while various physiological stresses induce alterations in the bacterial growth rate leading to biofilm formation. Because of their integral role in determining the success of orthopedic implants, the objective of this in vitro study was to examine the functions of (i) S. epidermidis and (ii) osteoblasts on ZnO and titania (TiO₂), which possess nanostructured compared to microstructured surface features. ZnO is a well-known antimicrobial agent and TiO₂ readily forms on titanium once implanted. Results of this study provided the first evidence of decreased S. epidermidis adhesion on ZnO and TiO₂ with nanostructured when compared with microstructured surface features. Moreover, compared with microphase formulations, results of this study showed increased osteoblast adhesion, alkaline phosphatase activity, and calcium mineral deposition on nanophase ZnO and TiO₂. In this manner, this study suggests that nanophase ZnO and TiO₂ may reduce S. epidermidis adhesion and increase osteoblast functions necessary to promote the efficacy of orthopedic implants. Read more

Multiple Self-Localized Electronic States in Trans-Polyacetylene

by Xi Lin et al. Proceedings of the National Academy of Sciences, 13 Jun 2006 Electronic structure calculations on a conjugated polymer chain by Hartree-Fock and density functional theory show a sequence of self-localized states, which stand in contrast to the single self-localized soliton state described by the Su-Schrieffer-Heeger model Hamiltonian. An extended Hubbard model, which treats electron-electron interactions up to second neighbors, is constructed to demonstrate that the additional states arise from a strong band-bending effect due to the presence of localized electric fields of charged solitons. We suggest the optical response of these electronic states may be associated with the near-edge oscillations observed in photo-induced absorption spectra. Our calculations indicate further that in the presence of counterions, the additional localized states continue to exist. Implications regarding soliton mobility and high-resolution ion sensing are briefly discussed. Read more

Microfabricated Surface-Electrode Ion Trap for Scalable Quantum Information Processing

by S. Seidelin et al. Physical Review Letters, 30 Jun 2006 Individual laser-cooled ²⁴Mg+ ions are confined in a linear Paul trap with a novel geometry where gold electrodes are located in a single plane and the ions are trapped 40 µm above this plane. The relatively simple trap design and fabrication procedure are important for large-scale quantum information processing (QIP) using ions. Measured ion motional frequencies are compared to simulations. Measurements of ion recooling after cooling is temporarily suspended yield a heating rate of approximately 5 motional quanta per millisecond for a trap frequency of 2.83 MHz, sufficiently low to be useful for QIP. Read more

Conjugated Chromophore Arrays with Unusually Large Hole Polaron Delocalization Lengths

by Kimihiro Susumu et al. Journal of the American Chemical Society, 9 Jun 2006 The future of high-speed electronics might very well be defined by linking together small, "electrically jumpy" molecules called chromophores. According to researchers at the University of Pennsylvania and St. Joseph's University, electrical charges can zip along chains of linked chromophores faster than any electrical charge yet observed in organic semiconductors, beating the previous benchmark in this regard by a factor of three. Their findings suggest the use of chromophore-based circuitry that could create nano-sized electronic components for numerous applications. Read more

Imaging Defects in Strained-Silicon Thin Films by Glancing-Incidence X-Ray Topography

by D. R. Black et al. Applied Physics Letters, 2 Jun 2006 X-ray topographical images from thin strained-Si films grown on relaxed, planarized crystalline SiGe-on-Si virtual substrates have been imaged by glancing-incidence monochromatic x-ray topography. This extremely asymmetric diffraction geometry, utilizing diffraction planes, can limit penetration into the sample to as little as 6 nm and allows separate images from the thin strained-Si film, the SiGe layer, and the base Si wafer to be recorded at different angles above the critical angle. Strain fields from the misfit dislocations in the SiGe layer penetrate the Si wafer and act as a template for the defect structure of the strained-Si films, even after an ex situ planarization step was inserted during the growth of the SiGe layer. This defect structure remains in the strained-Si film throughout the fabrication of strained-Si-on-insulator substrates. Read more

Researchers at UCLA Announce Breakthrough in Silicon Photonics Devices

University of California - Los Angeles Press Release, 28 Jun 2006 Turning the tables on chip power consumption: Rather than using electrical power, new silicon optical amplifiers generate it by harvesting energy normally wasted as heat Building on a series of recent breakthroughs in silicon photonics, researchers at the UCLA Henry Samueli School of Engineering and Applied Science have developed a novel approach to silicon devices that combines light amplification with a photovoltaic -- or solar panel -- effect. UCLA Engineering researchers report that not only can optical amplification in silicon be achieved with zero power consumption, but power can now be generated in the process. Read more

Mechanism for High-Tc Superconductivty Probed

by R. Colin Johnson EE Times, 6 Jul 2006 Researchers said they have moved a step closer to understanding the mechanism behind high-temperature superconductivity. The discovery of a high-temperature superconductor (bismuth strontium calcium copper oxide) by IBM in 1986 made lower-cost devices feasible. Since then, researchers have been trying to understand why these materials superconduct at such a high temperature. Their aim is to design materials that superconduct at even higher temperatures -- perhaps even at room temperature. Read more

Performance of STBC MC-CDMA Systems over Outdoor Realistic MIMO Channels

by Fabrice Portier, Jean-Yves Baudais, & Jean-François Hélard arXiv.org E-print Archive, 6 Jul 2006 The paper deals with orthogonal space-time block coded MC-CDMA systems in outdoor realistic downlink scenarios with up to two transmit and receive antennas. Assuming no channel state information at the transmitter, we compare several linear single-user detection and spreading schemes, with or without channel coding, achieving a spectral efficiency of 1-2 bits/s/Hz. The different results obtained demonstrate that spatial diversity significantly improves the performance of MC-CDMA systems, and allows different chip-mapping without notably decreasing performance. Moreover, the global system exhibits a good trade-off between complexity at mobile stations and performance. Then, Alamouti's STBC MC-CDMA schemes derive full benefit from the frequency and spatial diversities and can be considered as a very realistic and promising candidate for the air interface downlink of the 4th generation mobile radio systems. Read more

Joint Beamforming and Scheduling for SDMA Systems with Limited Feedback

by Kaibin Huang, Robert W. Heath, Jr, & Jeffrey G. Andrews arXiv.org E-print Archive, 29 Jun 2006 On a multi-antenna broadcast (downlink) channel, simultaneous transmission to multiple users is capable of achieving very high throughput. Unfortunately, the optimal approach for such multi-user transmission, namely dirty paper coding, is highly complicated. Therefore, this paper proposes a practical joint beamforming and scheduling scheme that is enabled by feedback of quantized channel state information. In this approach, the base station generates multiple sets of orthogonal beamforming vectors and associates each vector with a specific user. Next, the base station selects one set of beamforming vectors and the associated users for downlink transmission such that the throughput is maximized. Unlike the optimal approach, the proposed scheme has computational complexity that increases only linearly with the number of users since it does not require an exhaustive search over all possible subsets of users. Compared with two recently proposed schemes, the present scheme achieves higher downlink throughput, avoids multi-user conflicts when selecting beamforming vectors, requires no broadcast of beamforming vectors, and facilitates feedback compression. Read more

Performance Comparison of Multi-User Detectors for the Downlink of a Broadband MC-CDMA System

by Fabrice Portier et al. arXiv.org E-print Archive, 28 Jun 2006 In this paper multi-user detection techniques, such as Parallel and Serial Interference Cancellations, General Minimum Mean Square Error, and polynomial MMSE, for the downlink of a broadband Multi-Carrier Code Division Multiple Access system are investigated. The Bit Error Rate and Frame Error Rate results are evaluated, and compared with single-use. Read more

Silicon Valley Racing Ahead with Electric Cars

CNN.com, 29 Jun 2006 Like many Silicon Valley engineers, Martin Eberhard loves cars, especially fast ones. But the self-described "closet gearhead" didn't feel comfortable buying a hot rod that guzzled gas from the Middle East or some other troubled region. So three years ago, Eberhard and friend Marc Tarpenning launched Tesla Motors Inc. Their goal: to design a sports car that would go as fast as a Ferrari or Porsche, but run on electricity. Read more

'Bionic' Limb Breakthrough Made

BBC News, 3 Jul 2006 UK scientists have developed technology that enables artificial limbs to be directly attached to a human skeleton. The breakthrough, developed by researchers at University College London, allows the prosthesis to breach the skin without risk of infection. The team says early clinical trials have been "very promising." Read more

Environmental Health and Safety Database

The International Council of Nanotechnology's Environmental, Health and Safety (EHS) database contains citations and abstracts for research papers related to the EHS implications of nanoscale materials. Some entries have links to full papers, although site registration or payment may be required to access the full content of many of these articles. This database was developed initially by Dr. Tim Borges and Ms. LeeAnn Wilson at Oak Ridge National Laboratory. ICON EHS database