快猫短视频

This is a classic article from 快猫短视频鈥檚 archive, republished as part of our 50th anniversary celebrations

A JAPANESE scientist has discovered cylindrical carbon molecules, which he has dubbed 鈥渂uckytubes鈥� because of their similarity to fullerenes, or 鈥渂uckyballs鈥�. The cylinders are made of sheets of carbon atoms, arranged in hexagons, as in graphite. But instead of forming closed cages, as they do in fullerenes, the carbon atoms form open-ended cylinders.

Sumio Iijima, an electron microscopist at the fundamental research laboratory of NEC, the Japanese electronics giant, in Tsukuba, discovered the tubes when attempting to examine buckyballs in his transmission electron microscope. 鈥淚 found a structure I鈥檇 not seen before,鈥� he says. The buckyballs turned out to disintegrate in the intense beam of electrons which forms the image in an electron microscope.

The needles, or tubes, are up to a micrometre long and very fine. Typically, their outside diameter is between 4 and 30 nanometres. Iijima is excited by the helical arrangement of the hexagons. 鈥淭he preliminary result is that they are very good conductors,鈥� he says. But the pitch of the helix (its repeat length) varies, and 鈥渋f you choose a different pitch, the electronic properties seem to be different, and it can become an insulator,鈥� he adds. Iijima says he is trying to find the best recipe for making the tubes. He wants to make them longer than the current maximum of a micrometre, and to control their size and the pitch of the helix.

This article was originally published in 快猫短视频 on 16 November 1991

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