1. School of Mechanical and Electrical Information, Yiwu Industrial and Commercial College, Yiwu, 322000, P. R. China
2. Institute of Nonlinear Analysis and Department of Mathematics, Lishui University, Lishui, 323000, P. R. China
3. Department of Mathematics, Zhejiang Sci-Tech University, Hangzhou, 310018, P. R. China
4. Institute of Optoelectronic Technology and Department of Photoelectric Engineering, Lishui University, Lishui, 323000, P. R. China