the National Natural Science Foundation of China under Grant Nos.60673146, 60703017, 60736012, 60603049(国家自然科学墓金);the National High-Tech Research and Development Plan of China under Grant Nos.2006AA010201, 2007AAO1Z114(国家高技术研究发展计划(863));the National Basic Research Program of China under Grant No.2005CH321600(国家重点基础研究发展计划(973));the Beijing Natural Science Foundation of China under Grant No.4072024(北京市自然科学基金)