Funding for this research was provided by:
National Natural Science Foundation of China (11661009)
Guangxi Natural Science Fund for Distinguished Young Scholars (2015GXNSFGA139001)
Guangxi Natural Science Key Fund (2017GXNSFDA198046)
Innovation Project of Guangxi Graduate Education (YCSW2018046)
Article History
Received: 30 January 2019
Accepted: 27 August 2019
First Online: 18 September 2019
Competing interests
: The authors declare to have no competing interests.