Recirculation fumigation was carried out under the film covered the grain bulk through,adding recirculation ducts inside grain bulk,to solve the problem of application of recirculation fumigation in the warehouse without ventilation ducts.

This paper describes newly technology trend of component mounter and green technology of ductless reflow furnance.

Taking example for suspended reconnaissance missile which fall freely,using the interrelated program the windiness trajectory and no wind trajectory of.

Then according to the effect of correction to no wind trajectory,the drag characters (CA) of bomb-parachute system is found as foundanon numbers of the open parachute theory.

The Design of Ventiduct-detecting Robot;

Discussion on the pressure balance formula for ventilating duct;

Performance analysis and choosing of ventilating duct material;

Lagrangian simulation for particle deposition in square ventilating ducts;