Funding for this research was provided by:
National Natural Science Foundation of China (61379065)
Natural Science Foundation of Hebei Province (F2019203285)
Project funded by China Postdoctoral Science Foundation (2018M631763)
Yanshan University Doctoral Foundation (BL18010)
Natural Science Foundation of Hebei Province (F2019203526)
Article History
First Online: 29 October 2019
Compliance with ethical standards
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: The authors declare that they have no conflict of interest.