Showing Spotlights 1633 - 1640 of 2784 in category All (newest first):
There has been tremendous interest in cloaking technology using metamaterials and there are two exciting possibilities to obtain drastic scattering reduction from moderately-sized objects. One is the concept of plasmonic cloaking, which is based on the use of a thin metamaterial cover to suppress the scattering from a passive object. The second one is the concept of mantle cloaking, which is based on a simple impedance surface to achieve similar effects. Now, new research shows that even a single layer of atoms, with the exciting conductivity properties of graphene, may achieve similar functionality in planar and cylindrical geometries. Once realized, this concept represents the 'thinnest' possible cloak, operating in the THz spectrum.
Jun 30th, 2011
Nanoindentation is derived from the classical hardness test but is carried out on a much smaller scale. It can be used to determine the hardness of thin layers as well as material properties such as elasticity, stiffness, plasticity, and tensile strength, or fracture toughness of small objects and microsystems in fields such as biotechnology. These measurements involve applying a small force to a sample using a sharp probe and measuring the resultant penetration depth. The measured value is used to calculate the contact area and hence the particular property of the sample material. Both the method of force application and the geometry of the indentation tip can be adjusted to suit the particular application.
Jun 29th, 2011
Notwithstanding all the buzz about renewable energy sources, the dirty facts are that coal accounts for 41% of electricity production worldwide. Since, realistically, coal will be a mainstay of electricity generation for many years to come, research into more environmentally friendly use of coal energy is picking up steam. One technology for more efficient power production centers around the solid oxide fuel cell (SOFC). Especially gasified carbon fuel cells offer great prospects for the most efficient utilization of a wide variety of carbonaceous solids fuels, including coal, biomass, and municipal solid waste. Researchers have now developed a self-cleaning technique that could allow solid oxide fuel cells to be powered directly by coal gas at operating temperatures as low as 750 degrees Celsius.
Jun 28th, 2011
One enabling technology for printed and flexible electronics devices is the use of a special silver nanoparticle ink that allow the patterning of silver microelectrodes by omnidirectional printing. Taking an important step towards enabling desktop manufacturing - or personal fabrication - using very low cost, ubiquitous printing tools, researchers have now demonstrated a pen-on-paper approach as a low-cost, portable fabrication route for printed electronic and optoelectronic devices. The team demonstrates the fabrication of electronic art, flexible displays, conductive text, and radio frequency antennas with their technique. The printed features can withstand repeated bending and folding while maintaining high conductivity.
Jun 27th, 2011
Among various technologies, reverse osmosis membranes have been widely used for water reclamation. However, external energy required and high operational pressure used make reverse osmosis membrane water reclamation processes energy intensive - not exactly an advantage given the rising cost of energy and the negative climate impact of fossil fuels. Today, forward osmosis is a well-recognized osmotic process for producing clean water with a bright future as it uses a natural phenomenon and does not require any operational pressure hence it saves large amount of energy compared with reverse osmosis process. Researchers now describe a novel forward osmosis membrane that presents remarkable properties superior over conventional membrane support layers.
Jun 24th, 2011
It is not often that the prefix multipliers kilo and nano come together, and when they do, it usually is in the opening chapters of physical sciences textbooks where the point is made that the universe around us spans enormous space and time scales while operating in unimaginably small ones. We are truly awestruck and inspired by the tension. Kilometer-long nanowires do have a similar eponymous echo. Researchers have now reported the first successful fabrication of arrays of millions of ordered indefinitely long nanowires and nanotubes in a flexible polymer fiber. The results are kilometer-long nanowires - a novel approach to nanowire fabrication that might bring with it fresh solutions.
Jun 23rd, 2011
Conventional metal patterning in the electronics industry is done by a photo-resist patterning with a photo-mask and metal evaporation in a vacuum chamber. This technology require expensive vacuum conditions, high processing temperatures, many steps, and toxic chemicals to fabricate one layer of a metal pattern. Furthermore, it is almost impossible to change the design of the expensive photomask once it is fabricated. Researchers have now developed a high-resolution metal nano-patterning technique by combining solution deposited metal nanoparticles and a femtosecond laser without using conventional vacuum deposition or photo-masks. With this method, the time and cost associated with high-resolution metal patterning can be reduced dramatically without using time-consuming vacuum processes and the pattern design can be easily changed in a digital manner without using expensive photo-masks.
Jun 22nd, 2011
Researchers demonstrate a new single element nanoscale device, based on the successfully commercialized phase change material technology, emulating the functionality and the plasticity of biological synapses. In the nervous system, a synapse is the junction between two neurons, enabling the transmission of electric messages from one neuron to another and the adaptation of the message as a function of the nature of the incoming signal - something that is called plasticity. Synapses dominate the architecture of the brain and are responsible for massive parallelism, structural plasticity, and robustness of the brain. Therefore, a compact nanoelectronic device emulating the functions and plasticity of biological synapses will be the most important building block of brain-inspired computational systems.
Jun 21st, 2011