Heat spurs growth of tiny carbon trees.With a simple heating and cooling process, scientists can grow a forest of microscopic carbon trees on a surface, according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. a new study. In the past, scientists have used catalysts to stimulate the growth of nanotubes and other carbon structures on surfaces (SN: 8/21/99, p. 127). Catalysts, however, can be troublesome, says Pulickel M. Ajayan of Rensselaer Polytechnic Institute Rensselaer Polytechnic Institute, at Troy, N.Y.; coeducational; founded and opened 1824 as Rensselaer School; chartered 1826. It was called Rensselaer Institute from 1837 to 1861. in Troy, N.Y. Researchers first have to find appropriate ones and then remove them when the reaction is complete, he explains. Ajayan and his colleagues instead use a technique called flash chemical vapor deposition Vapor deposition Production of a film of material often on a heated surface and in a vacuum. Vapor deposition technology is used in a large variety of applications. . The researchers bathe a pair of graphite electrodes Electrodes Tiny wires in adhesive pads that are applied to the body for ECG measurement. Mentioned in: Electrocardiography in methane and helium, heat them quickly and briefly with an electric current, then allow them to cool. During each heat flash, carbon atoms Noun 1. carbon atom - an atom of carbon atom - (physics and chemistry) the smallest component of an element having the chemical properties of the element from the methane settle on the electrodes' surface. Over many heating and cooling cycles, thin cones of carbon with round heads sprout from the graphite. Ajayan and his coworkers report their findings in the March 16 NATURE. "These are really spectacular structures," says Ajayan. "Ultimately, we'd like to grow nanotubes with this technique." |
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