1. CCTEG Ecological Environment Technology Co., Ltd., Beijing 100013, China
2. School of Microelectronics, Xidian University, Xi′an 710071, China
3. College of Mathematics and Statistics, Jishou University, Jishou 416000, China
4. Changsha Research Institute of Mining and Metallurgy Co., Ltd., Changsha 410083, China
5. Technical Center for Soil, Agricultural and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing 100012, China