1. School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China e-mail:
2. Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 2G8, Canada e-mail:
3. Department of Mechanical Engineering, Shijiazhuang Railway Institute, Shijiazhuang 050043, China e-mail:
4. Department of Precision Instruments
and Mechanology, Tsinghua University, Beijing 100084, China e-mail:
5. Department of Mechanical Engineering, University of Cincinnati, Cincinnati, OH 45221-0072 e-mail: