Supposed by the Project of National Science Foundation for Distinguished Young Scholars of China under Grant No.60225008(国家杰出青年科学基金);the Key Project of National Natural Science Foundation of China under Grant Nos.603320lO,60575007(国家自然科学基金重点项目);the Project for Young Scientists' Foundation of National Natural Science of China under Grant No.60303022(国家自然科学基金青年科学基金);the Project of Natural Science Foundation of Beijing of China under Grant No.4052026(北京市自然科学基金);the Beijing Municipal Education Commission Foundation of China under Grant No.KM200610005011(北京市教委基金)