1. Department of Mechanics, Inner Mongolia University of Technology, Hohhot 010051, P. R. China
2. College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, P. R. China
3. College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot 010051, P. R. China
4. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, P. R. China