Funding for this research was provided by:
National Natural Science Foundation of China (61422311)
National Natural Science Foundation of China (61673263)
Hunan Provincial Natural Science Foundation of China (2015JJ1021)
National Natural Science Foundation of China (61503403)
Article History
Received: 3 May 2017
Accepted: 20 November 2018
First Online: 30 November 2018