1. Research Center of Nonlinear Science, College of Mathematics and Computer Science, Engineering Research Center of Hubei Province for Clothing Information, Wuhan Textile University, Wuhan 430200, P R. China
2. Department of Mathematics, Michigan State University, East Lansing, Michigan 48824, United States
3. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
4. Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824, United States