Liquid-solid phase transitions can be an attractive route for the temperature regulation of electrical and/or thermal properties because of the availability of materials with a wide range of phase transition temperatures. Achieving different magnitudes of enhancement in solid and liquid state is difficult to explain from a theoretical point of view. When researchers made similar experiments using single-walled carbon nanotubes as the additives, they noticed much higher thermal conductivity improvement than the evidence available in existing literature. This is something they never anticipated to happen and they were quite surprised with the enhancement seen.
Researchers in Korea have found that rice husks - the outer, protective covering of a rice kernel - can be a source of silicon that can be used for high-capacity lithium battery anodes. Most of today's lithium-ion batteries rely on anodes made from graphite, a form of carbon. There are several candidate electrodes to replace graphite as the anode for lithium-ion batteries and silicon has been recognized as a favorable anode material because its capacity is 3-5 times larger than those of existing graphite anodes. The new work demonstrates that rice husks can be used to produce silicon with an ideal porous nanostructure for use in high-capacity lithium-ion battery anodes.
One of the problems researchers have to struggle with in exploiting the extraordinary mechanical properties of carbon nanotubes (CNTs), for instance for building superstrong fibers or T-shirt-thin ballistic armors, has been the question of how to synthesis CNTs with macroscale lengths and without decreasing areal density. A crucial step for realizing such applications will be the ability to mass-produce carbon nanotubes with meter-scale or even kilometer-scale length and excellent mechanical properties. In new work, a team of researchers from Tsinghua University in Beijing have found that the growth of ultralong carbon nanotubes could be described using Schulz-Flory distribution, which is very common in polymer science.
Colorimetric sensing techniques require only the naked eye or ordinary visible color photography and are attractive because of their low cost, use of inexpensive equipment, and above all, their simple-to-understand results. Researchers have now developed a plasmonic colorimetric assay to detect mercuric ion based on urine. Compared to other gold-nanoparticle-based colorimetric systems, it showed excellent selectivity to mercury ions and good sensitivity as high as can be used for mercury ion detection in industrial wastewater.
In the past few years, dialogues have become increasingly important for politics and science as well as scientific communication. More and more, they serve as an important feature for the responsible handling of nanotechnology at the national and European level. German speaking states have therefore laid emphasis on dialogues as a tool for communication and information in their nanotechnology action plans. The projects described in the following were largely initiated by the respective authorities as implementation measures of the national nanotechnology action plans.
New research shows that ordered intermetallic core-shell nanocatalysts are highly promising designs for fuel cells. These are the newest members to platinum-iron alloy nanocatalysts with such intermetallic core-shell (IMCS) design. Furthermore, on characterizing them after 10,000 cycles, they still retain their structural ordering at the core while the platinum shell got thicker and thicker. Such a static core-dynamic shell (SCDS) regime is being reported for the first time.
One of the most restricting parameters in nanofabrication is the difficulty involved with controllably patterning materials at precise locations in a repeatable manner over relatively large areas. A novel microelectromechanical system (MEMS)-based mask writer has now been developed by a team of researchers. The device allows to directly write structures at the nanoscale without the need to use photoresist, lift-off techniques or other complex and expensive approaches. The technique uses a MEMS plate with apertures drilled into it and a shutter so that one can, in effect, spray paint with atoms.
Edge magnetism is a unique property of graphene ribbons that has been predicted by theory, but not yet directly confirmed experimentally. If researchers want to utilize zigzag graphene nanoribbons (zGNRs) in spintronics, they first need to figure out a suitable termination group for zGNRs. The often used hydrogen atom termination is not a good choice since hydrogen terminated zGNRs can only be stabilized at extremely low hydrogen concentrations. In new work, researchers designed special boundaries for zGNRs that could become both stable and maintain the edge magnetism.