NSF of ChinaNational Natural Science Foundation of China (NSFC) [10971229, 11161015, 11371367, 11361012]; PSF of China [2012M512162, 2013T60934]; NSF of Hunan Province [11JJ900, 12JJ9001, 13JJ4098]; Education Foundation of Hunan Province [12C0541, 13C084]; Science Foundation of Hengyang Normal University [11B36]; construct program of the key discipline in Hunan Province