In this paper, we have discussed a special geomatric figure—the rectangle divided into some squares, and raise a theorem and six characters on the number of special route in the rectangle divided some squares.

The construction step of grid diagram and the network evolution method were introduced.

Band Gap Structures of 2D Triangular Lattice Photonic Crystals;

Service status of several common checker was introduced,some open questions on checker in China were pointed out and computational method of checker volume was presented.

It is pointed out that the clearing of regenerator checkers by liquefied petrol gas can give the following advantages : easy operating, cost saving,product quality improving and furnace campaign prolonging.

The blockage of semi-connection regenerator from collapse of checker-work brick lead exhaust gas to leave out and increase furnace pressure, which intensify furnace damage.

Photonic bandgaps of two-dimensional photonic crystals with graphite lattice;