The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was supported by the Major Program of National Natural Science Foundation of China (grant no.: 51490662), the Natural Science Foundation of Hunan Province of China (grant no.: 2017JJ2012), and the Educational Commission of Hunan Province of China (grant no.: 17A036, 17C0044).