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.
It has long been known that free, ionic silver particles can be highly toxic to aquatic organisms. Yet we a lack of detailed knowledge about the doses required to trigger a response and how the organisms deal with the stress. To learn more about the cellular processes, scientists in Switzerland subjected algae to a range of silver concentrations. The results are reassuring, but the presence of other stressors could compound the problem.
Associated with unhappy visits to the dentist, “cavity” means something else in the science of optics. An arrangement of mirrors that allows beams of light to circulate in closed paths, or cavities, help us build laser and optical fibers. Now, a research team pushed the concept further by developing an optical “nanocavity” that boosts the amount of light that ultrathin semiconductors absorb.
A new study from the International Electrotechnical Commission and the Fraunhofer Institute in Europe has found that nanotechnology will bring significant benefits to the energy sector, especially to energy storage and solar energy. Improved materials efficiency and reduced manufacturing costs are just two of the real economic benefits that nanotechnology already brings these fields and that’s only the beginning.
Last year, a physicist and a mechanical engineer at Northeastern Univ. combined their expertise to integrate electronic and optical properties on a single electronic chip, enabling them to switch electrically using light alone. Now, they have built three new devices that implement this fast technology: an AND-gate, an OR-gate and a camera-like sensor made of 250,000 miniature devices.
Every second, your computer must process billions of computational steps to produce even the simplest outputs. Imagine if every one of those steps could be made just a tiny bit more efficient. A Northeastern Univ. team has developed a series of novel devices that do just that. The team combined their expertise to unearth a physical phenomenon that could usher in a new wave of highly efficient electronics.
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.
Researchers have devised a way of making tiny holes of controllable size in sheets of graphene, a development that could lead to ultra-thin filters for improved desalination or water purification. The team of researchers succeeded in creating subnanoscale pores in a sheet of the one-atom-thick material, which is one of the strongest materials known.
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.
Researchers from NIST and the FDA have demonstrated that they can make sensitive chemical analyses of minute samples of nanoparticles by, essentially, roasting them on top of a quartz crystal. The NIST-developed technique, "microscale thermogravimetric analysis," holds promise for studying nanomaterials in biology and the environment, where sample sizes often are quite small and larger-scale analysis won't work.
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.
A light-activated drug delivery system for treating cancer is particularly promising to traditional chemotherapy methods because it can accomplish spatial and temporal control of drug release. To this end, scientists have developed a new type of nanoparticle that can absorb energy from tissue-penetrating light that releases drugs in cancer cells.
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.
A tabletop device invented at Rice Univ. can tell how efficiently a nanoparticle would travel through a well and may provide a wealth of information for oil and gas producers. The device gathers data on how tracers, microscopic particles that can be pumped into and recovered from wells, move through deep rock formations that have been opened by hydraulic fracturing.
From steel beams to plastic Lego bricks, building blocks come in many materials and all sizes. Today, science has opened the way to manufacturing at the nanoscale with biological materials. Potential applications range from medicine to optoelectronic devices. In a paper published in Soft Matter, scientists announced their discovery of a 2-D crystalline structure assembled from the outer shells of a virus.
A pathway to more effective and efficient synthesis of pharmaceutical drugs and other flow reactor chemical products has been opened by a study in which, for the first time, the catalytic reactivity inside a microreactor was mapped in high resolution from start-to-finish. The results not only provided a better understanding of the chemistry behind the catalytic reactions, they also revealed opportunities for optimization.
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.
Univ. of Colorado Boulder scientists have found a creative way to radically improve thermoelectric materials, a finding that could one day lead to the development of improved solar panels and more energy-efficient cooling equipment. The technique, building an array of tiny pillars on top of a sheet of thermoelectric material, represents an entirely new way of attacking a century-old problem.
A multi-university team of engineers has developed what could be a promising solution for charging smartphone batteries on the go, without the need for an electrical cord. Incorporated directly into a cell phone housing, the team's nanogenerator could harvest and convert vibration energy from a surface, such as the passenger seat of a moving vehicle, into power for the phone.
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 team of Belgian researchers have made what may be the first optical circuit that uses interconnections that are not only bendable, but also stretchable. These new interconnections, made of a rubbery transparent material called PDMS, guide light along their path even when stretched up to 30% and when bent around an object the diameter of a human finger.
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.