国家自然科学基金项目No.31270498,31170423;高等学校博士学科点专项科研基金No.20135103110002;四川省杰出青年学术与技术带头人培育项目No.2012JQ0008,2012JQ0059;中国博士后科学基金特别资助项目No.2012T50782;Supported by the National Natural Science Foundation of China No.31270498,31170423,the Doctoral Program Foundation of Institutions of Higher Education of ChinaNo.20135103110002,the Sichuan Youth Science&Technology FoundationNo.2012JQ0008,2012JQ0059and the Post-doctoral Foundation of China No.2012T50782