Funding for this research was provided by:
Natural Science Foundation of China (11801574, 11571370, 11601525)
Natural Science Foundation of Hunan Province (2017JJ2213, 2019JJ50788)
Research Foundation of Education Bureau of Hunan Province (18A452)
Fundamental Research Funds for Central Universities of the Central South University (2019CX022)
Huaihua University Scientific Research Project (HHUY2019-3)
Article History
Received: 10 December 2018
Accepted: 24 September 2019
First Online: 3 October 2019
Competing interests
: The authors declare that they have no competing interests.