作者机构:[1]School of Mathematical Sciences, Inner Mongolia University, Hohhot 010021, China, [2]College of Sciences, Inner Mongolia University of Technology, Hohhot 010051, China
相关基金:Project supported by the National Natural Science Foundation of China (Grant Nos. 11061019 and 10962004), the Chunhui Program of Ministry of Education of China (Grant No. Z2009-1-01010), the Natural Science Foundation of Inner Mongolia, China (Grant Nos. 2010MS0110 and 2009BS0101), and the Cultivation of Innovative Talent of '211 Project' of Inner Mongolia University.