1. Department of Materials Science and Engineering
2. College of Engineering
3. Peking University
4. Beijing 100871
5. People's Republic of China
6. Micro- and Nanotechnology Research Center
7. Harbin Institute of Technology
8. Harbin 150080
9. China
10. Department of Materials Physics and Chemistry
11. School of Materials Science and Engineering
12. University of Science and Technology Beijing
13. Beijing 100083
14. Department of Chemistry
15. Dalian Medical University
16. Dalian 116044