Monday, January 19, 2004

Carbon nanotubes, long, thin cylinders of carbon, were discovered in 1991 by S. Iijima. [22] These are large macromolecules that are unique for their size, shape, and remarkable physical properties. They can be thought of as a sheet of graphite (a hexagonal lattice of carbon) rolled into a cylinder. These intriguing structures have sparked much excitement in the recent years and a large amount of research has been dedicated to their understanding. Currently, the physical properties are still being discovered and disputed. What makes it so difficult is that nanotubes have a very broad range of electonic, thermal, and structural properties that change depending on the different kinds of nanotube (defined by its diameter, length, and chirality, or twist). To make things more interesting, besides having a single cylindrical wall (SWNTs), nanotubes can have multiple walls (MWNTs)--cylinders inside the other cylinders.

ok now we know what are nanotubes ....but I really don't know what's thier application and what's the point of a tube of carbon!!!????and how come it's self assembling?

ok but what is nanotbes??

Nanotubes are essentially what they sound like - tubes (cylinders with a hollow center) that have nanoscale dimensions. Typically, the tubes are very long in length. Scientists have made nanotubes out of carbon and other elements. Naturally, different elements will have slightly different properties, but what makes nanotubes attractive is their potential. They exhibit unique electrical properties and unique strength profiles (they are very strong considering their dimensions).
Engineers are starting to add carbon nanotubes to enhance the performance of certain products. For example, automobile tires, tennis balls, and even materials for space travel. A lot of potential exists for these unique devices, it's just a matter of time before we'll find them everywhere.

Sunday, January 18, 2004

Nanowire or nanotube?

Intel said that it is working with Harvard and other universities on silicon nanowires and carbon nanotubes, two experimental structures made up of, respectively, self-assembling silicon and carbon atoms. After 2010, one of these technologies could begin to replace standard transistors and over time become the building block of chips.

Description: The bottom, light part of this electron microscope image shows he silicon core of a nanowire and the dark part shows the germanium outer shell. The spheres are individual atoms. The scale bar is 5 nanometers.
The Harvard researchers are working on making a high-performance field-effect transistor that could be integrated with conventional electronic circuitry, said Lieber. "We are pushing very hard to make [a] transistor that could find its way into hybrid devices," he said. "This is something we're discussing with Intel's advanced transistor group."

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