Construct Program of the Key Discipline in Hunan Province; NSF of ChinaNational Natural Science Foundation of China (NSFC) [10971229, 11161015, 11371367]; PSF of China [2012M512162]; NSF of Hunan Province [11JJ900, 12JJ9001, 13JJ4098]; Education Foundation of Hunan province [12C0541, 13C084]