Funding for this research was provided by:
National Natural Science Foundation of China (61866002)
Guangxi Natural Science Foundation (2018GXNSFAA138122;2015GXNSFAA139293)
Innovation Project of Guangxi Graduate Education (YCSW2018203)
Innovation Project of GuangXi University of Science and Technology Graduate Education (GKYC201706; GKYC201803)
Article History
Received: 5 October 2018
Revised: 9 April 2019
Accepted: 1 May 2019
First Online: 21 May 2019