Showing Spotlights 1641 - 1648 of 2340 in category All (newest first):
The development of electron-beam lithography, focused ion beam milling, and other nanofabrication techniques has provided researchers with great freedom to pattern metallic structures at the nanoscale. This has fueled the design and implementation of new ultracompact photonic devices based on the plasmonic behavior of metals. Plasmonics is an emerging field of nanophotonics that relies on hybrid light-charge density waves on metal-dielectric interfaces and holds the promise for control of light at dimensions much below the free-space wavelength of light. Lenses have always been an important component for controlling light in optical systems. The focusing capability of conventional, dielectric-based microlenses however deteriorates as their physical dimensions are reduced toward a single-wavelength scale. That's why scientists have begun exploring alternative approaches to refractive lensing. While nano-patterning of optically thick metallic films was theoretically proposed as an alternative to refractive lensing, scientists at Stanford University have now reported the first experimental demonstration of far-field lensing using a plasmonic slit array.
Dec 19th, 2008
Synthetic fibers are ubiquitous in modern society and their manufacture represents a huge, multi-billion dollar worldwide industry. Synthetic fibers - carbon fibers, nylon, polyester, kevlar, spandex, etc. - are manufactured from fossil fuels, usually from oil, but sometimes from coal or natural gas. Most of these materials are not biodegradable and, in addition to their significant carbon footprint during production, they pose environmental problems at the end of their life cycle. Natural fibers, on the other hand, such as wool and cotton, come from renewable animal or plant sources but they usually lack the high-performance characteristics of many synthetic fibers. This may change, as the new field of bio-based nanomaterials promises to deliver environmentally friendly, high-performance bio-fiber materials that can replace some of the synthetic materials.
Dec 18th, 2008
Companies manufacturing, using, or selling nanoproducts in the Unites States would be well-served, at this early stage, to think proactively about minimizing future litigation risks. Candidly, the legal world has thus far lagged behind the growth in nano-related products and enterprises. But if the encyclopedic history of toxic tort, product liability, and environmental litigation in this country is any guide whatsoever, there is no reason enterprising plaintiffs' attorneys are less likely to tackle nanotechnology than other lucrative products and technological advances. Indeed, references to a potential link between carbon nanotubes and lung cancer have already sprouted on plaintiff-oriented websites across the country.
Dec 17th, 2008
Researchers have demonstrated that salmon DNA can be used to develop a simple and scalable method for sorting carbon nanotubes that reduces the cost, as compared to commonly used synthetic DNA, by a factor of 1,000. Before carbon nanotubes (CNTs), especially single-walled ones, can live up to the many expectations for their use in nanoelectronics, researchers have to overcome a seemingly trivial but nonetheless major obstacle: how to separate a produced batch of nanotubes according to their properties such as diameter, length, chirality and electronic attributes. Current production methods for CNTs result in a jumble of units with different properties, all lumped together in bundles, and often blended with some amount of amorphous carbon. These mixtures are of little practical use since many advanced applications, especially for nanoelectronics, are sensitively dependent on tube structures and the slightest deviation from a desired set of parameters can lead to vastly different performance results.
Dec 16th, 2008
Climate change is high on the global agenda. While the United Nations Climate Change Conference in Poznan, Poland, in December 2008, is an important step towards achieving an international agreement on climate change scheduled for the upcoming Conference of the Parties in Copenhagen at the end of 2009, policy makers and practitioners alike are increasingly looking for practical solutions. A new report by the United Nations University Institute of Advanced Studies (UNU-IAS) offers three innovative solutions in responding to climate change, namely nanotechnology, ocean energy and forestry. The 46-page report goes beyond the technological, biological and procedural aspects of these solutions by critically assessing the opportunities and challenges that each type of innovation presents. This report addresses the question why these innovations - despite their large potential to reduce emissions, ocean energy alone could cover the world's electricity needs - have not yet reached the stage of mass commercialization
Dec 15th, 2008
A new report prepared for the German Federal Ministry of Education and Research outlines an institutional model that meets the safety and security demands of human health, the environment and society. The report draws on an analysis of national and international approaches to nanotechnology regulation.
One of the key findings is that in the case of developing nanotechnologies, the place of classical regulation has been taken by precautionary measures such as observatories, voluntary codes of conduct and stakeholder dialogues. The development of an institutional model is proposed, the Scanning Probe Agency (SPA), as both a necessary and appropriate collective learning process and a means of generating public trust. Its guiding question would be: 'Is nanotechnology in good hands?'
Dec 12th, 2008
The hydrogen that will power tomorrow's cars is not a naturally occurring resource that can be tapped by drilling a hole in the ground. Hydrogen has to be produced, and that can be done using a variety of resources. The cleanest by far of course would be renewable energy electrolysis: using electricity to split water into hydrogen and oxygen; this electricity could be generated using renewable energy technologies such as wind, solar, geo- and hydrothermal power. As it stands, most of today's hydrogen production is 'dirty' - it is produced from methane in natural gas using high-temperature steam in what is called steam methane reforming. Many research groups around the world are working hard on developing cheap, clean and efficient technologies to produce hydrogen from water, particularly using sunlight (artificial photosynthesis). This would be the ultimate clean, renewable and abundant energy source. However, to become commercially viable, fuel cells have to overcome the barrier of high catalyst cost caused by the exclusive use of expensive platinum and platinum-based catalysts in the fuel-cell electrodes - the reason is that platinum is the most efficient electrocatalyst for accelerating chemical reactions in fuel cells. Scientists have found that platinum catalysts can be replaced with bacteria-produced hydrogenase enzymes that have nickel and iron in their active sites.
Dec 10th, 2008
The performance of devices like organic light emitting diodes (OLEDs), flexible solar cells, or plastic electronics is sensitive to moisture because water and oxygen molecules seep past the protective plastic layer over time and degrade the organic materials which form the core of these products. To protect these sensitive devices, barrier technologies have been developed that protect them from environmental degradation. State-of-the-art barrier materials employ metal oxide thin films, commonly from aluminum or silicon oxides, which provide excellent protection from atmospheric oxygen and water, but still suffer from problems. A new study demonstrates a nanocomposite material that can initiate self-healing upon the influx of water through pores and cracks by delivering titanium dioxide nanoparticles to the defective site, which ultimately slows the rate of moisture diffusion to the reactive electronic device.
Dec 9th, 2008