†the corresponding author. Email address:math−lhliang@163.com(H. Liu) 1School of Mathematics and Physics, University of South China, Hengyang, 421001, China 2School of Mathematics and Computational Science, Hunan First Normal U-niversity, Changsha, 410205, China 3School of Mathematics and Statistics, Central South University, Changsha, 410083, China ∗The authors were supported by the Hunan Natural Science Fund Youth Fund Project(No. 2018JJ3419), Scientific Research Fund of Hunan Provincial E-ducation Department(Nos. 17C1362 and 17C1364) and Doctoral Funds of SCU(Nos. 2016XQD40 and 2016XQD42).
