1. College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, China
2. Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, China
3. Department of Technical Centre, Hunan Sheng Provincial Quality Supervision and Inspection Institute, Changsha, Hunan, China
4. College of Mathematic and Econometrics, Hunan University, Changsha, Hunan, China