1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 201139, China
2. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
3. Department of Mechanical Engineering, California State University, Los Angeles, California 90032, United States
4. College of Energy, Beijing University of Chemical Technology, Beijing 100029, China
5. Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States