Huang, Wenyuan
Liang, Yan
Ma, Xiaofeng
Funding for this research was provided by:
Youth Innovation Promotion Association (2012315)
Beijing Municipal Education Commission (KM201910029001)
Article History
Received: 2 March 2019
Accepted: 27 May 2019
First Online: 31 May 2019
Ethics approval and consent to participate
: Not applicable, no human subjects.
: Not applicable, no human subjects.
: The authors declare that they have no competing interests.