1. Research Center of Nonlinear Science, School of Mathematical and Physical Sciences, Wuhan Textile University, Wuhan, P R. China
2. Department of Mathematics, Michigan State University, East Lansing, MI, United States
3. Key Laboratory of Computational Mathematics, Guangdong Province, and School of Mathematics, Sun Yat-sen University, Guangzhou, P R. China
4. Electrical and Computer Engineering and
5. Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States