On April 25th Norwegian F-16s hit Colonel Qaddafi's residential compound in the middle of Tripoli, destroying administrative offices and a command centre.

A halogen element, f, is major raw materials deriving fluorine compound, and because of low melting point, that is widely used in steelmaking, nonferrous metal smelting, cement, glass and ceramics.

In view of the actual operating mode, analyzed the correct meshing condition to the compound gear and the pin-track, in order to realize the high production and highly effective has laid the f.