Funding for this research was provided by:
National Natural Science Funding of China (71473248, 71673271, 71473247, and71273258)
the Major project of National Social Science Funding of China (16ZDA056)
Humanities and Social Sciences Research Project of Hebei Higher Education Institutions (SQ181020)
National Natural Science Foundation of China (71871084)
Article History
Received: 2 February 2018
Accepted: 12 August 2019
First Online: 16 August 2019
Ethics approval and consent to participate
: This research was approved by the China University of Mining and Technology Institutional Review Board (IRB). We employed a questionnaire survey to obtain the data, which is a traditional and widely recognized method used in the field of social science research. In China, it is unnecessary to receive the written consent of participants by convention. Thus, the “Ethics Statement” included in the questionnaire instructions clearly stated that “only respondents who agreed to the instructions participated in the survey.” All of the participants read and approved the statement before they participated in the survey.
: Not applicable.
: The authors declare that they have no competing interests.