1. Department of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, P. R. China
2. Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
3. Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
4. School of Physics, Liaoning University, Shenyang, Liaoning 110036, P. R. China
5. Michigan Center for Materials Characterization, University of Michigan, Ann Arbor, Michigan 48109-2102, United States
6. Department of Materials Science, University of Michigan, Ann Arbor, Michigan 48109, United States