国家自然科学基金资助项目51078035,21177010;高等学校博士学科点专项科研基金20100014110004;人力资源和社会保障部留学回国人员科技活动择优资助重点项目;the National Natural Science Foundation of China51078035,21177010;the Ph.D.Programs Foundation of the Ministry of Education of China20100014110004;the Technology Foundation for Selected Overseas Chinese Scholar,Ministry of Personnel of China