1. Department of Applied Physics, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
2. Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
3. School of Physics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, P. R. China
4. 75310 Army, 25 Zhongnan Road, Wuhan 430071, P. R. China
5. School of Mathematics and Physics, China University of Geosciences, 388 Lumo Road, Wuhan 430074, P. R. China