1. College of Teacher Education, Chongqing Three Gorges University, Chongqing 404100, China
2. Institute for Structure and Function, Chongqing University, Chongqing 401331, China
3. College of Electronic and Information Engineering, Chongqing Three Gorges University, Chongqing 404100, China
4. School of Mathematical Sciences and Physics, Jinggangshan University, Ji’an 343009, China