This work was supported by National Natural Science Foundation of China (31370680, and 31400556), the Natural Science Foundation of Hubei Province (2013CFA039), the Foundation for Innovative Research Groups of Natural Science of Hubei Province (2011CDA117), and International Science and Technology Cooperation Project of Hubei Province (2013BHE029 and 2013BHE039), and the Graduate Innovative Project of Jiangsu Province (2013CXZZ13-D551).