1. College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
2. Department of Chemistry, City University of Hong Kong, Hong Kong, SAR 999077, P. R. China
3. Department of Advanced Materials Engineering, Chung-Ang University, Seoul 156-756, South Korea
4. Beamline Research Division, Pohang Accelerator Laboratory (PAL), Pohang 37673, Korea