Funding for this research was provided by:
National Natural Science Foundation of China (71673073, 71473064)
Program for New Century Excellent Talents in University (1252-NCET02)
Heilongjiang Provincial Association of Social Sciences (15058)
Received: 3 April 2019
Accepted: 16 June 2020
First Online: 24 June 2020
Ethics approval and consent to participate
: Not applicable to this study.
: This manuscript has not been published or presented elsewhere in part or in entirety and is not under consideration by another journal. All study participants provided informed consent, and the study design was approved by the appropriate ethics review board. We have read and understood your journal’s policies, and we believe that neither the manuscript nor the study violates any of these.
: No competing interests.