Nanotube Technology

Please choose the most appropriate answer for each sentence.
  • 1

    CNTs (carbon nanotubes) have probably been around for a lot longer than was first realized, but ..... microscopy at that time was not advanced enough to distinguish them from other types of tubes.

  • 2

    The first method for producing CNTs and fullerenes in ..... quantities was by applying an electric current across two carbonaceous electrodes in an inert gas atmosphere.

  • 3

    This method is called plasma arcing: it involves the evaporation of one electrode as cations followed by ..... at the other electrode.

  • 4

    The carbon arc discharge method is the most common and easiest way to produce CNTs, but it produces a complex mixture of components and requires further purification to separate the CNTs from the soot and the ..... catalytic metals present in the crude product.

  • 5

    This method creates CNTs through arc-vaporization of two carbon rods placed end to end, separated by approximately 1mm, in an enclosure that is usually filled with ..... gas at low pressure.

  • 6

    Another method of nanotube synthesis involves plasma arcing in the ..... of cobalt with a 3% or greater concentration.

  • 7

    The nanotube product is a compact cathode deposit of rod-like ......

  • 8

    However, when cobalt is added, the nature of the product changes to a web, with strands of 1mm or so thickness that stretch from the cathode to the walls of the reaction ......

  • 9

    The ..... by which cobalt changes this process is unclear, however one possibility is that such metals affect the local electric fields and hence the formation of the five-membered rings.

  • 10

    Arc-discharge and laser vaporization are currently the principal methods for obtaining small quantities of high quality CNTs, but both methods suffer from .....: the CNTs are difficult to purify, manipulate, and assemble for building nanotube-device architectures for practical applications.