1. Faculty of Mechanical Engineering and Automation Zhejiang Sci-Tech University Hangzhou Zhejiang 310018 P. R. China
2. Automotive Tribology Center Department of Mechanical Engineering School of Engineering and Computer Science Oakland University Rochester MI 48309 USA
3. Key Laboratory of Automobiles Materials Department of Materials Science and Engineering Jilin University Changchun Jilin 130025 P. R. China