Affiliation: | 1. School of Mathematics and Computational Science,Changsha University of Science and Technology,Changsha 410076,China;School of Mathematics and Computational Science,Xiangtan University,Xiangtan 411105,China 2. Dept.of Mathematics,Harbin Institute of Technology,Harbin 150001,China 3. School of Mathematics and Computational Science,Xiangtan University,Xiangtan 411105,China 4. School of Mathematics,Central South University,Changsha 410075,China |