Supported in part by NSFC(No.11401009);Anhui Provincial Natural Science Foundation(No.1408085QA01);the Key Natural Science Foundation of Anhui Educational Committee(No.KJ2014A082)
supported by NSFC(No.11471108);Natural Science Foundation of Hunan Province(Nos.2015JJ2051,2016JJ2050);Scientific Research Foundation of Hunan Provincial Education Department(No.12B101);the Teaching Reform Foundation of Hunan Province(No.G21316)