Showing Spotlights 1777 - 1784 of 2424 in category All (newest first):
Since SWCNTs are sensitive to their chemical environment, they can be intentionally doped by a variety of dopants such as iron chloride, ammonia or nitrogen dioxide. But they can also be unintentionally doped. Scientists have known for some time that something funny happens when nanotubes are sonicated in certain solvents - sometimes their electronic properties change. Since mass produced nanotubes are clumped into bundles and ropes, they need to be dispersed prior to further processing in order to separate the individual nanotubes. A popular way of doing this is by exposing the CNT samples to ultrasonic pressure waves. Adding a dispersing reagent into the solution will accelerate the dispersion effect. New research now sheds light on how and why the electronic structure of carbon nanotubes changes during sonication.
Sep 29th, 2008
'Smart' is the key buzz word used by materials engineers when they describe the future of coatings, textiles, building structures, vehicles and just any material that you can think of. Materials are made 'smart' when they are engineered to have properties that change in a controlled manner under the influence of external stimuli such as mechanical stress, temperature, humidity, electric charge, magnetic fields etc. Smart materials have some form of sensor capability that detects a change in the material or its environment that then triggers some kind of action. Not only for use in smart materials but as general sensor materials, especially for monitoring large areas, the development of materials that act as 'chemical paints' - or coatings - by responding to a (bio)chemical parameter with a change in their optical properties has developed into an exciting new field. In a typical application, the object of interest is painted and the color or fluorescence of the paint is monitored by methods of optical imaging. This technique represents a simple but exciting new technology to monitor (bio)chemical and even physical parameters over relatively large areas and in real time without having to look at only a minute sample through a microscope.
Sep 26th, 2008
Nanotechnology applications could provide decisive technological breakthroughs in the energy sector and have a considerable impact on creating the sustainable energy supply that is required to make the transition from fossil fuels. Possibilities range from gradual short- and medium-term improvements for a more efficient use of conventional and renewable energy sources all the way to completely new long-term approaches for energy recovery and utilization. With enough political will - and funding - nanotechnology could make essential contributions to sustainable energy supply and global climate protection policies. The technological foundation is there, all it takes is political leadership to create the right research and investment conditions to make it happen.
Sep 25th, 2008
Radio frequency ablation (RF ablation) is a treatment for cancer that works by inserting a thin needle guided by computed tomography or ultrasound through the skin and into a tumor. Electrical energy is then delivered through a number of electrodes deployed through the needle, causing a zone of thermal destruction that encompasses the tumor. Researchers have experimented with non invasive radiowave thermal ablation of cancer cells that uses nanoparticles as a novel approach to treat cancer. The idea is that RF treatment of malignant tumors at any site in the body should be possible if it were possible to get agents that release heat under the influence of the RF field to the specific tumor site. Researchers have now developed a novel nanomaterial that has proven to be a very strong RF absorber and provides high enough thermal-ablation ability in order to generate localized thermally-driven damages inside the cancer cells. Even more, these nanoparticles have shown relatively low cytotoxicity and they absorb low frequency RF radiation, which has significant penetration depth inside living organism.
Sep 24th, 2008
The concept of a 'machine' - a mechanical or electrical device that transmits or modifies energy to perform a certain task - can be extended to the nano-world. On the nanoscale, the nanomachine components would be atomic or molecular structures each designed to perform a specific task which, all taken together, would result in a complex function. However, these nanomachines can not be built by just further miniaturizing machine blueprints from the macro-world. Functional nanomachinery will need to take into account the quantum effects that dominate the behavior of matter at the nanoscale, affecting the optical, electrical and magnetic behavior of materials. Scientists in The Netherlands are now reporting how an atomic scale mechanical device consisting of two moving parts, each composed of only two atoms can be controlled by an external electrical signal, while being stable and providing a variety of functional modes. They jokingly refer to it as playing atomic pinball, since the two moving parts resemble the flippers in a pinball machine - unfortunately they haven't got a ball yet to play with.
Sep 23rd, 2008
The processes by which molecules pass through pores in thin films and biological membranes are essential for understanding various physical, chemical and biological phenomena. For instance, the fundamental behavior of molecules in porous solids and their transfer through cell membranes necessarily involves a process of molecules passing through pores - knowledge that, for instance, is crucial for the development of nanotechnology-based hydrogen storage materials for fuel tanks. So far, research methods have been based on studying the statistical average of the behavior of groups of molecules; there were no experimental approaches that examined the interaction of a single molecule with a pore. There has been a lack of experimental methods that can obtain information on the structure and orientation of the molecules as they pass through a pore, and their interactions with the pore during passage. Researchers in Japan have now succeeded for the first time in observing a long chain of a fullerene-labeled hydrocarbon passing through a nanometer-size pore in the wall of a carbon nanotube as if it were alive.
Sep 22nd, 2008
Travel through wormholes, time machines and hovering landspeeders are the stuff of science fiction novels. Nevertheless, scientists have suggested that the quantum mechanics of something called the Casimir effect can be used to produce a locally mass-negative region of space-time, a phenomenon that theoretically could be used to stabilize a wormhole to allow faster than light trave. For many years the Casimir effect was little more than a theoretical curiosity. With the advances in micro- and nanotechnology and the fact that the Casimir force affects nanoscale devices such as NEMS, research in detecting and manipulating this mysterious force has generated substantial interest. Now, the secretive DARPA, a research agency of the U.S. Department of Defense that often dabbles in far-out technologies - and that also brought us the Internet's predecessor ARPANET - is soliciting innovative research proposals in the area of Casimir Effect Enhancement.
Sep 19th, 2008
For nanoelectronics applications like single-electron devices to become practical, everyday items, they need to move from the highly individual and customized fabrication process typically found in laboratories to an automated, high-throughput and industrial-scale production environment. The reason this hasn't happened yet is that the various nanoscale pattern definition techniques used today - such as e-beam lithography, mechanically controllable break junctions, electromigration, electrodeposition, nanoscale oxidation, and scanning tunneling microscopy - generally are not suitable for large-scale parallel processing. The fabrication of single-electron devices requires nanoscale geometrical arrangement of device components, that is, source and drain electrodes and Coulomb islands. Developing methods to fabricate nanoscale devices in large numbers at a time has been one of the major efforts of the nanotechnology community. A new study now demonstrates that this can be done with complete parallel processing using CMOS-compatible processes and materials. Furthermore, these single-electron devices can operate at room temperature, an essential requirement for practical implementations.
Sep 18th, 2008