Funding for this research was provided by:
National Science Foundation (21566030)
Scientific Research Program of Higher Education Institutions of Inner Mongolia Autonomous Region (B2016101)
Graduate Research and Innovation Projects of Jiangsu Province (X201307)
Natural science foundation of Inner Mongolia autonomous region (2015MS0217)
Article History
Received: 23 September 2019
Accepted: 7 December 2019
First Online: 9 January 2020
Compliance with ethical standards
: The work of this study conforms to ethical standards.
: There are no conflicts to declare.