1. School of Information Science & Engineering, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China
2. Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China
3. Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Science, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China