U.K. scientists have succeeded in measuring how the surfaces of glassy materials flow like a liquid, even when they should be solid. A series of simple and elegant experiments were the solution to a problem that has been plaguing condensed matter physicists for the past 20 years. The finding has implications for thin-film coating designs.
A team of researchers has developed a material that could help prevent blood clots associated with catheters, heart valves, vascular grafts and other implanted biomedical devices. Blood clots at or near implanted devices are thought to occur when the flow of nitric oxide, a naturally occurring clot-preventing agent generated in the blood vessels, is cut off. When this occurs, the devices can fail.
A big step in the development of advanced fuel cells and water-alkali electrolyzers has been achieved with the discovery of a new class of bimetallic nanocatalysts that are an order of magnitude higher in activity than the target set by the U.S. Department of Energy for 2017. The new catalysts feature a 3-D catalytic surface activity that makes them significantly more efficient and far less expensive than the best platinum catalysts.
Ultraviolet light (UV) has not only harmful effects on molecules and biological tissue like human skin but it also can impair the performance of organic solar cells upon long-term exposure. Researchers in Germany have now developed a so-called plasmonic metamaterial which is compatible with solar technology and completely absorbs UV light despite being only 20 nm thin.
How heat flows at the nanoscale can be very different than at larger scales, and researchers are working to understand how these features affect the transport of the fundamental units of heat, called phonons. At Cornell Univ. scientists have invented a phonon spectrometer whose measurements are 10 times sharper than standard methods. This boosted sensitivity has uncovered never-before-seen effects of phonon transport.
Cornell Univ. researchers have recently led what is probably the most comprehensive study to date of block copolymer nanoparticle self-assembly processes. The work is important, because using polymers to self-assemble inorganic nanoparticles into porous structures could revolutionize electronics.
A Chinese-U.S. research team is exploring the use of metamaterials to create devices that manipulate sound in versatile and unprecedented ways. In a recently published paper, the team reports a simple design for a device, called an acoustic field rotator, which can twist wave fronts inside it so that they appear to be propagating from another direction.
While taking in the scenery during long road trips, passengers also may be taking in potentially harmful ultrafine particles (UFPs) that come into the car through outdoor air vents. Closing the vents reduces UFPs, but causes exhaled carbon dioxide to build up. Now, scientists have developed a high-efficiency cabin air filter that could reduce UFP exposure by 93% and keep carbon dioxide levels low.
Researchers at Argonne National Laboratory in collaboration with scientists at Northwestern Univ. are the first to grow graphene on silver which, until now, posed a major challenge to many in the field. Part of the issue has to do with the properties of silver, the other involves the process by which graphene is grown.
Mottronics is a term seemingly destined to become familiar to aficionados of electronic gadgets. Named for the Nobel laureate Nevill Francis Mott, Mottronics involve materials that can be induced to transition between electrically conductive and insulating phases. If these phase transitions can be controlled, Mott materials hold promise for future transistors and memories that feature higher energy efficiencies and faster switching speeds.
When deciding what materials to use in building something, determining how those materials respond to stress and strain is often the first task. A material’s macroscopic, or bulk, properties in this area is generally the product of what is happening on a microscopic scale. When stress causes a material’s constituent molecules to rearrange in a way such that they can't go back to their original positions, it is known as plastic deformation.
To attach itself to surfaces, the marine sponge Monorhaphis chuni forms an unusual glass rod. Researchers have recently analyzed the nanostructure of the filament passing through the center of this glass rod and discovered that it is formed with a perfect periodic arrangement of nanopores. In this way, the sponge employs a similar method that is now used for fabrication of man-made mesoporous nanomaterials.
Previous efforts to create graphene nanoribbons followed a top-down approach, using lithography and etching process to try to cut ribbons out of graphene sheets. Cutting ribbons 2 nm-wide is not practical, however, and these efforts have not been very successful. Now, a research team has developed a chemical approach to mass producing these graphene nanoribbons. This process that may provide an avenue to harnessing graphene's conductivity.
Researchers in the U.K. have developed a method of controlling the composition of a range of polymers, the large molecules that are commonly used as plastics and fibers. They have demonstrated how the chemical reactions can be manipulated, especially in fixing the composition of a polymer using a mixture of up to three different monomers. The secret lies in understanding and switching “on” and “off” the catalyst used to make the polymers.
The scarcity of ultraviolet (UV) light in sunlight has held back the usefulness of titanium dioxide-based photocatalysts. Through the application of nanotechnology, researchers in Japan have recently succeeded in the development of better titanium dioxide-based material that can be activated by visible light. The solution lies in an array of nanoparticles that “simulate” the photoexcitation of UV light.
Computers don’t need to be error-free. They just need to correct their errors reliably, which means that controlling a quantum system is crucial to the function of a quantum computer. A research team has now found a way to control the quantum system of a diamond which has a few nitrogen impurities. They have used the system to perform a logic operation and error correction in a quantum register made from nuclear spins of the gemstone.
A research collaboration consisting of IHP-Innovations for High Performance Microelectronics in Germany and the Georgia Institute of Technology has demonstrated the world's fastest silicon-based device to date. The investigators operated a silicon-germanium (SiGe) transistor at 798 GHz fMAX, exceeding the previous speed record for silicon-germanium chips by about 200 GHz.
On a pound-per-pound basis, carbon nanotube-based fibers invented at Rice Univ. have greater capacity to carry electrical current than copper cables of the same mass, according to new research. While individual nanotubes are capable of transmitting nearly 1,000 times more current than copper, the same tubes coalesced into a fiber using other technologies fail long before reaching that capacity.
Superconductor “recipes” are frequently tweaked by swapping out elements or manipulating the valence electrons to strike the perfect conductive balance. Most high-temperature superconductors feature only one orbital impacting performance. But what about introducing more complex configurations? Now, Brookhaven National Laboratory’s physicists have combined atoms with multiple orbitals and precisely pinned down their electron distributions.
An undesired effect in thin film amorphous silicon solar cells has puzzled the scientific community for the last 40 years. This effect, known as light-induced degradation, is responsible for reducing solar cell efficiency over time. Researchers in Germany have recently demonstrated that tiny voids within the silicon network are partly responsible for 10 to 15% efficiency loss as soon as they are used.
A team in France has greatly miniaturized the light-emitting diode (LED) by creating one from a single polythiophene wire placed between the tip of a scanning tunneling microscope and a gold surface. This nanowire, which is made of the same hydrogen, carbon and sulfur components found in much larger LEDs, emits light only when the current passes in a certain direction.
Modern electronics relies on utilizing the charge properties of the electron. The emerging field of atomtronics, however, uses ensembles of atoms to build analogs to electronic circuit elements. Physicists have built a superfluid atomtronic circuit that have allowed them to demonstrate a tool that is critical to electronics: hysteresis. It is the first time that hysteresis has been observed in an ultracold atomic gas.
New research at the Univ. of Arkansas reveals a novel magnetoelectric effect that makes it possible to control magnetism with an electric field. The novel mechanism may provide a new route for using multiferroic materials for the application of RAM (random access memories) in computers and other devices, such as printers.
An international partnerships is aiming to develop robust fingerprint sensors with resolution beyond today’s 500 dpi international standards, the minimum required by the U.S. Federal Bureau of Investigation. The new platform uses vertical piezoelectric nanowire matrices designed using multiphysics modeling software.
An international team has recently unveiled a superconducting pairing mechanism in calcium-doped graphene. The pairing, which was using a angle-resolved photoemission spectroscopy method, is important because graphene is easily doped or functionalized with chemicals, allowing scientists to more fully explore the nature of superconductivity.