1. Department of Mathematics, School of Sciences, Nanchang University, Nanchang, P. R. China
2. Department of Mathematics, School of Sciences, Nanchang University, Nanchang, P. R. China bNumerical Simulation and High-Performance Computing Laboratory, School of Sciences, Nanchang University, Nanchang , P. R. China
3. School of Statistics, University of International Business and Economics, Beijing, P. R. China
4. Department of Mathematics, School of Sciences, Nanchang University, Nanchang, P.R. China + Numerical Simulation and High-Performance Computing Laboratory, School of Sciences, Nanchang University, Nanchang, P. R. China