1. Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen 518055, P. R. China
2. Department of Electrical and Electronic Engineering, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen 518055, P. R. China
3. Department of Mechanical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 00000, Hong Kong