Funding for this research was provided by:
National Natural Science Foundation of China (U160411067, U1404301, 31700435)
Program for Scientific & Technology Innovation Talents in Universities of Henan Province (18HASTIT039)
Science and Technology Department of Henan Province (172102110197)
Science and Technology Department of Henan Province (162102210260)
Project for Youth Outstanding Teachers of Henan Province (2015GGJS-091)
Article History
Received: 30 November 2018
Accepted: 10 May 2019
First Online: 20 May 2019
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.