Showing Spotlights 2001 - 2008 of 2140 in category (newest first):
Fuel cells are electrochemical energy conversion devices for the direct conversion of the chemical energy of a fuel into electricity. They are among the key enabling technologies for the transition to a hydrogen-based economy. Of several different types of fuel cells under development today, polymer electrolyte fuel cells (PEFCs) have been recognized as a potential future power source for zero emission vehicles. However, to become commercially viable, PEFCs have to overcome the barrier of high catalyst cost caused by the exclusive use of platinum and platinum-based catalysts in the fuel-cell electrodes. Researchers at Los Alamos National Laboratory now demonstrate a new class of low cost (non-precious metal)/(heteroatomic polymer) nanocomposite catalysts for the PEFC cathode, capable of combining high oxygen-reduction activity with good performance durability. The results of their study show that heteroatomic polymers can be used not only to stabilize the nonprecious metal in the acidic environment of the PEFC cathode but also to generate active sites for oxygen reduction reaction.
Oct 6th, 2006
Because of the huge effective surface area, the ability to blend different types of polymers, and the fact that the process is conducted at room temperature so that biological compounds can be loaded into the fibers, electrospinning has enormous potential to create new families of higher performance products across a wide array of industry sectors. For a technique invented in 1934, we are just now beginning to see its true potential.
Oct 5th, 2006
Researchers have developed an original process to investigate the spin transport properties of a single nanoparticle and provided evidence for its successful realization. This new approach paves the way for a more in-depth study of magneto-Coulomb phenomena in nanosized clusters. While only two results are available up to now on connecting a 0D nano-object to ferromagnetic electrodes enabling spin polarized injection and detection, extensive theoretical studies have been undertaken, leaving the field wide open for experiments.
Oct 4th, 2006
The potential use of antimicrobial surface coatings ranges from medicine, where medical device infection is associated with significant healthcare costs, to the construction industry and the food packaging industry. Thin films which contain silver have been seen as promising candidate coatings. Silver is known as one of the oldest antimicrobial agents. Silver ions are thought to inhibit bacterial enzymes and bind to DNA. Silver has been used effectively against different bacteria, fungi and viruses. Researchers in Germany developed a new method for producing antibacterial metal/polymer nanocomposite coatings, where silver and gold nanoparticles are only incorporated in a thin surface layer. The new material shows a greatly enhanced antibacterial efficiency of the thin films.
Oct 3rd, 2006
Seashells are natural armor materials. The need for toughness arises because aquatic organisms are subject to fluctuating forces and impacts during motion or through interaction with a moving environment. Nacre (mother-of-pearl), the pearly internal layer of many mollusc shells, is the best example of a natural armor material that exhibits structural robustness, despite the brittle nature of their ceramic constituents. This material is composed of about 95% inorganic aragonite with only a few percent of organic biopolymer by volume. New research at the university of South Carolina reveals the toughening secrets in nacre: rotation and deformation of aragonite nanograins absorb energy in the deformation of nacre. The aragonite nanograins in nacre are not brittle but deformable. The new findings may lead to the development of ultra-tough nanocomposites, for instance for armor material, by realizing the rotation mechanism.
Oct 2nd, 2006
Individual carbon nanotubes (CNTs) of different structural and thus electronic characteristics can be joined to build up three-terminal logic devices. However, today this can only be achieved using highly sophisticated nanomanipulation processes. The direct growth of intrinsic functional CNT elements such as Y-shaped CNTS (YCNTs) and helical CNTs (HCNTs) can be considered as an important alternative. YCNTs already have proven to show rapid and nonlinear transistor action without the need for external gating, while HCNTs could be used as inductive elements offering rapid signal processing. Additionally, HCNTs have shown operational functionality as high sensitivity force and mass sensors and are of great interest for nanoelectromechanical systems (NEMS). A research group in Spain now reports that sulfur may be used as a highly efficient additive in chemical vapor deposition (CVD) processes, allowing enhanced selectivity in the synthesis of helical and Y-shaped CNTs.
Sep 29th, 2006
Imagine to catch one, or a few, molecules dissolved in water, lock them up in a cage with a diameter of a few hundred nanometers, and keep them locked for a given length of time. Then bring these containers with the "captive" molecules to places within the solution where you want to have them, and release the captured molecules from their captivity on chemical command. Or simply keep the molecules in the cage "prison" locked up, add a few more different molecules to water, and watch their chemical reaction following movement across the container wall in "solitary" confinement within the containers with the molecules already captured. Such dreams of nanotechnologists have come much closer to reality as a result of a discovery made by a team of researchers, lead by Professor Julius Vancso of the University of Twente, from the MESA+ Institute for Nanotechnology collaborating with scientists of the Max Planck Institute of Colloids and Interfaces in Golm, Germany.
Sep 28th, 2006
Spintronics (short for "spin-based electronics") is an emergent technology which exploits the quantum propensity of electrons to spin as well as making use of their charge state. The spin itself is manifested as a detectable weak magnetic energy state characterized as "spin up" and "spin down". Spin flip length is an important parameter to know for designing spintronics devices. Because in spintronics, electron spin carries the information, it is important to know how far electrons can travel in a device before this spin information is lost. In a discovery that could contribute to the emerging field of spintronics, scientists at Oak Ridge National Laboratory (ORNL) and the Institute of Physics, Chinese Academy of Science, have demonstrated a way to measure the distance an electron travels in nanoscale materials before its spin is reversed due to scattering.
Sep 27th, 2006