1. Department
of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong SAR, China
2. Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, China
3. National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, Taiwan