基金supported in part by the National Natural Science Foundation of China under Grants no. 11101054 , 11101434Hunan Provincial Natural Science Foundation of China under Grant no. 12JJ4005+3 种基金the Scientific Research Funds of Hunan Provincial Science and Technology Department of China under Grants no. 2013FJ4035Humanities and Social Sciences Foundation of Ministry of Education of China under Grants no. 12YJAZH173the National Innovation Foundation for Undergraduate no. 201410536011Changsha University of Science and Technology Innovation Foundation for Postgraduate no. CX2014YB19
