1. Key Laboratory of Manufacturing Equipment of the Shaanxi Province, School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710048, Shaanxi, China
2. Key Laboratory of Manufacturing Equipment of the Shaanxi Province, School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710049, Shaanxi, China
3. Petro China Lanzhou Lubricating Oil R & D Institute, Lanzhou 730060, Gansu, China