1. Department of Chemistry
2. Capital Normal University
3. Beijing 100048
4. P. R. China
5. CAS Key Laboratory of Standardization and Measurement for Nanotechnology
6. CAS Center for Excellence in Nanoscience
7. National Center for Nanoscience and Technology
8. Beijing 100190
9. School of Mechanical Engineering
10. Hebei University of Technology
11. Tianjin 300401