Funding for this research was provided by:
National Natural Science Foundation of China (11571292, 11471279)
National Natural Science Foundation of China (11771370)
Hunan Provincial Natural Science Foundation of China (2018JJ2376, 2017JJ3305)
the Youth Project of Hunan Provincial Education Department of China (16B257)
Article History
Received: 17 July 2018
Accepted: 30 May 2019
First Online: 13 June 2019
Competing interests
: The authors have no any competing interests in the subject of this research.