Supported by the National Natural Science Foundation of China under Grant No.60403018;60773077(国家自然科学基金);the National Basic Research Program of China under Grant No.2005CB321905(国家重点基础研究发展计划(973));the Postdoctoral Science Foundation Funded Project of China under Grant No.20070420257(中国博士后科学基金);the Natural Science Foundation of Shanghai of China under Grant No.04ZR14011(上海市自然科学基金);Collaboration Plan of AMD with Universities(AMD大学合作计划)