1. School of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
2. Department of Mathematics and Physics, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
3. School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
4. Department of Mathematics and Physics, and Hebei Key Laboratory of Physics and Energy Technology, North China Electric Power University, Baoding 071003, China