1. State Key Laboratory of Solid Lubrication
2. Lanzhou Institute of Chemical Physics
3. Chinese Academy of Sciences
4. Lanzhou 730000
5. China
6. School of Materials Science & Engineering
7. Lanzhou University of Technology
8. Lanzhou 730050
9. Shaanxi University of Science and Technology
10. Xi'an 710021
11. College of Chemical Engineering & Technology
12. Tianshui Normal University
13. Tianshui 741001
14. Institute for Chemical Physics & Department of Chemistry