The beginning time of HouJin master s dominance is always a controversial issue in academic circles.

Diplomacy Between Later Jin under Nurhaci and Kingdom of Joseon and Its Effects;

On the Legal Measures used by Later Jin Dynasty to Pacificate Monan-Mongolia;

Based on the basic principles of differential geometry the locus equation of the movement of the grinding wheel center during clearance face grinding of the major cutting edge of a ball nose end milling cutter with equal orthogonal clearance angle is deduced,which supply the NC grinding of the clearance face of a ball nose end milling cutter with a feasible mathematical mode