US Patent 7625530 - Manufacture of isotope-doped CNTs

http://www.freepatentsonline.com/7625530.html

Isotope labeling is a technique used to study nanoscale growth mechanisms. This patent from Tsinghua University and Hon Hai Precision teaches an arc discharge method using isotope doping to study the growth process. Claim 1 reads:

1. A method for manufacturing isotope doped carbon nanotubes, comprising the steps of:

(a) providing a carbon rod connected with an anode of an electrical source, the carbon rod comprising at least two kinds of carbon isotope segments arranged alternately along a longitudinal direction of the carbon rod;

(b) providing a pure carbon rod connected with a cathode of the electrical source, the pure carbon rod positioned corresponding to the carbon rod; and

(c) producing an arc discharge between the carbon rod and the pure carbon rod, the carbon isotope segments of the carbon rod being consumed in sequence to form the isotope doped carbon nanotubes.