1. Control Science and Engineering Department, University of Shanghai for Science and Technology, Shanghai 200093, P. R. C.; Mathematics and Physics Department, Hohai University, Changzhou Campus, Changzhou 213022, P. R. C.
2. Control Science and Engineering Department, University of Shanghai for Science and Technology, Shanghai 200093, P. R. C.
3. College of Science, University of Shanghai for Science and Technology, Shanghai 200093, P. R. C.