Carbon nanotubes are minute pipes made of graphite, the form of carbon familiar in pencil lead. Carbon atoms in graphite naturally organize themselves into two-dimensional sheets or lattices in a chicken wire or beehive like hexagonal lattice. Modern fabrication techniques can roll up such sheets into ultra thin tubes 100,000 times smaller than a human hair -- less than 2 nanometers in diameter. Twisting such tubes can drastically change their electronic properties, from conductors, to semiconductors. A main focus of interest now is their use in flat panel displays.
The experiment used semiconductor nanotubes two nanometers in diameter and 3,000-5000 nanometers long But when the experimenters added noise -- random electrical activity -- generated by several alternate methods, the signal came through. The noise makes the fragmentary picture suddenly recognizable. Kosko believes that increased awareness of the stochastic resonance phenomenon can aid designers of communications, including especially modern spread-spectrum devices, which often rely on an array of faint signals. "Nano-device designers can individually tailors nanotubes to specific signals and then deploy them in numbers -- rather like pipe organs tuned to different notes -- to take advantage of the SR-effects, " he said.
http://www.eurekalert.org/pub_releases/2003-12/uosc-tst121603.php
posted by jnmullendore @ Thursday, October 26, 2006
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