1. The State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
2. Qingdao Center of Resource Chemistry & New Materials, Qingdao 266071, China
3. State Key Laboratory of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan 250100, China
4. College of Mechanical and Electronic Engineering, China University of Petroleum, Qingdao 266580, China
5. Department of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea