1. School of Mechanical Engineering , Hebei University of Technology , Tianjin , , PR China
2. Research Institute for Structure Technology of Advanced Equipment , Hebei University of Technology , Tianjin , , PR China
3. School of Economics and Management , Tianjin University of Science and Technology , Tianjin , China
4. Key Laboratory for Micro/Nano Technology and Systems of Liaoning Province , Dalian University of Technology , Dalian , China