Funding for this research was provided by:
The Outstanding Youth Science Foundation of Hunan Province of China (2019JJ20028)
The Open Research Fund Program of Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines (E21827)
The Natural Science Foundation of Hunan Province of China (2017JJ2296)
Article History
Received: 22 July 2020
Accepted: 23 December 2020
First Online: 7 January 2021
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.