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Richard E. Smalley's group at Rice University (http://cnst.rice.edu/reshome.html)has studied the application of carbon nanotubes as probes for scanning tunneling microscopes. They found that nanotubes have many advantages over conventional probes. First of all, nanotubes do not break when they "crash" into the surface being studied. Instead, they buckle, and return to their original form when retracted. Second, the tubes are smaller than the probes currently used, so they can reach into narrower trenches and give a better image. Third, the small diameter of the nanotube reduces the force of the water holding the probe in place (most surfaces to be probed are either covered in water from normal humidity conditions or have been deliberately flooded), making for easier movement of the probe.
The Zettl Research Group at Berkeley (http://www.physics.berkeley.edu/research/zettl/projectlist.html) is "investigating creative ways to catalyze the production of nanotubes from
carbon as well as other elements." They want to find a way to produce a large amount of carbon nanotubes of the same shape. They are also trying to find out as much as possible
about the physical properties of nanotubes, through several types of spectroscopy and microcopy. One member of the group is attempting to learn about the chemistry of nanotubes
by reacting them with other substances.
The possibility of using nanotubes to make very tiny gears has been explored by D.H. Robertson (http://www.chem.iupui.edu/Research/Robertson/Robertson.html). He formed the tubes into gears and shafts joined together, and ran tests with the gears rotating with their teeth interlocking. For all speeds except the very fastest attempted, this was successful, with the teeth staying on track.
Cees Dekker (http://vortex.tn.tudelft.nl/~dekker), along with his Delft group at the Delft University of Technology, is studying the electrical properties of single molecule carbon nanotubes. Their work has shown that currents with densities of up to about 109 A/cm2 (amps per square centimeter) can be run through carbon nanotube wires without the wire fusing. This is many orders of magnitude larger than the fusing current density for a normal copper wire. They have also demonstrated that nanotubes can be thought of as one-dimensional boxes, just as in the "particle in a box" model.
Image at Right: Representation of Carbon Nanogears. Courtesy of Dr. D. H. Robertson of IU/PU I