基金We would Like to thank Dr. Ge-Tu Zhaori for helpful discussion.This work was supported by tHe grants from the National Science Fund for Distinguished Young Scholars （No. 30725019）, the National Natural Science Foundation of China （No. 81030021）, and the National Basic Research Program of China （No. 2006CB504502, No. 2011 CB504403, and No. 2011CB505200）.