Funding for this research was provided by:
the National Natural Science Foundation of China (71373020, 71271055)
the Beijing Municipal Key Programs of Education Sciences during the 13th Five-Year Plan Period (BAEA18043)
postgraduate research and innovation fund of the University of International Business and Economics (201832)
joint doctor training program of the University of International Business and Economics (JS20190202)
Article History
First Online: 4 August 2020
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.