Funding for this research was provided by:
National Natural Science Foundation of China (71472174, 61533019, 71232006, 61233001)
Hunan Natural Science Foundation of China (2017JJ336)
Article History
Received: 1 January 2018
Revised: 26 January 2018
Accepted: 31 January 2018
First Online: 19 February 2018
Compliance with ethical standards
:
: The authors declare that there is no conflict of interests regarding the publication of this paper.