国家自然科学基金项目(50777015;50837001);国家863高技术基金项目(2007AA05Z240);国家重点基础研究发展计划项目(973项目)(2009CB219705);Project Supported by National Natural Science Foundation of China(50777015;50837001);The National High Technology Research and Development of China 863 Program(2007AA05Z240);The National Basic Research Program of China(973 Program)(2009CB219705)