基金Supported by the National Natural Science Foundation of China under Grant Nos.10571112, 60673105(国家自然科学基金)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE, China(高等学校优秀 青年教师教学科研奖励计划)the National Basic Research Program of China under Grant No.2002CB312200(国家重点基础研究发展 计划(973))