National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [21003014, 21001017, 21275022]; Natural Science Foundation of Hunan Province, ChinaNatural Science Foundation of Hunan Province [13JJ3068, 10JJ5002]; Scientific Research Fund of Hunan Provincial Education DepartmentHunan Provincial Education Department [12C0007]; Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation (Changsha University of Science Technology) [2014CL05]