Supposed by the National Natural Science Foundaion of China under Grant Nos.60534060;60473094(国家自然科学基金);the National High-Tech Research and Development Plan of China under Grant No.2007AA01Z136(国家高技术研究发展计划(863));the National Basic Research Program ofChina under Grant No.2003CB317002(国家重点基础研究发展计划(973))