1. Nonlinear Scientific Research Center, Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, People's Republic of China
2. School of Mathematical Sciences, Nanjing Normal University, Nanjing, Jiangsu, People's Republic of China
3. School of Science of Nanjing University of Posts and Telecommunications, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu, People's Republic of China