Showing Spotlights 1465 - 1472 of 2424 in category All (newest first):
Among the various production methods for carbon nanotubes and graphene, currently only chemical vapor deposition techniques demonstrate a significant opportunity for mass production of CNT material. Using the CVD process, which is based on the catalytic action of metals, manufacturers can combine a metal catalyst such as iron with reaction gases such as hydrogen to form carbon nanotubes inside a high-temperature furnace. In order to optimize the synthesis process, a detailed understanding of the interaction between nanotubes or graphene and metal atoms is required - something that has been missing so far. Researchers in France have now shown that it is possible to create atomic-scale defects in carbon nanotubes and in graphene in preselected positions with a focused electron beam and to use these defects as trapping centers for foreign atoms.
May 31st, 2010
Carbon nanotubes' interesting structural, chemical, electrical, and optical properties are explored by numerous nanomedicine research groups around the world with the goal of drastically improving performance and efficacy of biological detection, imaging, and therapy applications. In many of these envisaged applications, CNTs would be deliberately injected or implanted in the body, for instance as intercellular molecular delivery vehicles. One of the issues researchers have been exploring is how - once the primary role of CNTs in a therapeutic application is fulfilled - they can promote the rapid removal of CNTs from the body, or the dispersal of aggregated clusters to sub-micron size in order to mitigate the harmful effects. Researchers in India have now demonstrated a novel, optical tweezers based approach to scavenge CNTs from biological fluids such as blood.
May 27th, 2010
Graphite oxide sheet, now being named graphene oxide - a compound of carbon, oxygen, and hydrogen obtained by treating graphite with strong oxidizers - has attracted substantial interest as a possible intermediate for the manufacture of graphene. It has been largely viewed as hydrophilic - having a strong affinity for water illustrated by its excellent colloidal stability in water. In what should help to better understand and improve the solution processing of graphite oxide-based graphene materials and open up opportunities to design new functional graphite oxide-based hybrid materials, researchers have now reported that graphite oxide is amphiphilic - possessing both hydrophilic and lipophilic (fat-liking) properties - and can adsorb onto air-water, oil-water and solid-water interfaces.
May 26th, 2010
Aberrations in optical systems, which leads to blurring of the image, and their elimination using adaptive optics have been studied in astronomical research for quite a long time. Aberrations occur when light from one point of an object after transmission through the optical system does not converge into a single point. The complicated part in correcting this error usually lies in identifying the aberrations that need to be eliminated from the system. With the emergence of nanoscale applications, aberrations in modern microscopy have become a severe limitation on the optimal performance in imaging, nanosurgery, nanofabrication and micromanipulation, just to name a few. Researchers have now demonstrated a powerful method for aberration correction with a simple implementation that typically requires minimal changes in the particular geometry.
May 25th, 2010
Metal nanomaterials are often synthesized using the toxic reagent formaldehyde at concentrations thousands of times higher than necessary. Many of these same nanomaterials are being investigated for use in cancer treatment - however, there is a risk that they could do more harm than good. The large excess of formaldehyde that is used originates from methods developed 100 years ago. Because these methods work well, they have stood the test of time. By better understanding the role that formaldehyde plays in nanomaterial synthesis it will become possible to reduce or eliminate this toxic reagent. By eliminating formaldehyde it will become safer to prepare these nanomaterials and safer to use them in cancer treatment.
May 24th, 2010
Electrically conductive composite materials capable of substantial elastic stretch and bending - conductive rubbers - is an industrially important field. The composites are needed for such applications as smart clothing, flexible displays, stretchable circuits, strain gauges, implantable devices, high-stroke microelectromechanical systems, and actuators. A variety of approaches involving carbon nanotubes and elastic polymers have been suggested for the fabrication of conductive elastic composites. Various studies indicated that high loading of CNTs or other conductive additives into the polymer was necessary to obtain a highly conducting composite. A research team has now demonstrated that a combination of high stretchability and high electrical conductivity can be obtained for composites prepared from three-dimensional CNT structures.
May 21st, 2010
The development of artificial muscles is one of the key areas for bionic enhancements or replacements. The discovery of the electromechanical actuation properties of single-walled carbon nanotubes and the complex behavior of multi-walled carbon nanotubes has led to the development of various carbon nanotube actuators. Besides artificial muscles, potential applications include microelectro-mechanical systems (MEMS), biomimetic micro-and nanorobots, and micro fluidic devices. Recently, a new class of active system, carbon nanotube/polymer composite actuators, has received great attention with regard to macroscopic artificial muscle applications. It has been demonstrated that successful introduction of the highly conductive CNTs could significantly enhance the polymer nanocomposite's electrical, thermal, mechanical, and interface properties, thus providing a suitable material for novel artificial muscle-like actuator investigations.
May 19th, 2010
The ability to extract, dispense and manipulate very small amounts of liquids on the micro- and nanoscale is important in biotechnology, chemistry and also for patterning inorganic, organic and biological inks. Several methods for dispensing liquids exist, but many require complicated electrodes and high-voltage circuits. Researchers in Italy have now demonstrated a pyroelectrohydrodynamic droplet dispenser based on pyroelectric forces.Researchers in Italy have developed and demonstrated a completely new method for extracting and dispensing very small amounts of liquid - as small as few attoliters - from liquid droplet reservoirs or thin liquid films by a method called pyroelectrohydrodynamic (Pyro-EHD).
May 18th, 2010