1. Department of Chemical Engineering, Hunan University, Changsha, 410082 Hunan, P. R. China
2. Department of Mathematics and
Physics, Jingchu University of Technology, Jingmen, 448000 Hubei, P. R. China
3. Zhejiang Shuyang Chemical Co. Ltd., Quzhou, 31000 Zhejiang, P. R. China