1. College of Geophysics and Information Engineering, China University of Petroleum, Beijing 102249, China
2. College of Science, Hebei United University, Tangshan 063000, China
3. School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710048, China
4. Department of Mathematics, University of Salerno, Via Ponte don Melillo, Fisciano, 84084 Salerno, Italy
5. Department of Mathematics and Mechanics, China University of Mining and Technology, Xuzhou, Jiangsu 221008, China