Institution: | 1. Faculty of Mathematics and Physics, Huaiyin Institute of Technology, Huai’an, Jiangsu 223003, PR China;2. Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, PR China;3. College of Science, Nanjing University of Aeronautics & Astronautic, Nanjing, Jiangsu 210016, PR China |