Funding for this research was provided by:
National Natural Science Foundation of China (71502141)
Project of Humanities and Social Sciences of Ministry of Education in China (16YJA630069)
Article History
First Online: 20 November 2019
Compliance with Ethical Standards
: 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 Helsinki Declaration and its later amendments or comparable ethical standards.
: The authors declare that they have no conflict of interests.