Funding for this research was provided by:
the National Natural Science Foundation of China (61672217, 61602164)
the National Natural Science Foundation of China (61702172)
the Natural Science Foundation of Hunan Province, China (2018JJ3076, 2018JJ2063)
the Fundamental Research Funds for the Central Universities
Article History
Received: 6 July 2017
Revised: 26 June 2020
Accepted: 29 June 2020
First Online: 15 July 2020