Funding for this research was provided by:
Guangxi College Enhancing Youths Capacity Project (KY2016LX315, KY2016YB404)
National Natural Science Foundation of China (41461110,11461001)
Text and Data Mining valid from 2019-03-28
Received: 12 June 2018
Accepted: 5 February 2019
First Online: 28 March 2019
: The author declares that there is no conflict of interests.