作者机构:[1]School of Mathematical Sciences and Computing Technology, Central South University, Changsha410075, China, [2]School of Mathematics and Computing Sciences, Hunan University of Science and Technology, Xiangtan 411201, China
相关基金:Supported by the NSFC (10771058, 11071062, 10871205), NSFH (10JJ3065), Scientific Research Fund of Hunan Provincial Education Department (10A033), and Hunan Provincial Degree and Education of Graduate Student Foundation (JG2009A017).