Li, Shan http://orcid.org/0000-0001-6001-1586
Zheng, Juan
Article History
First Online: 1 September 2018
Compliance with Ethical Standards
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: The data can be obtained on request in electronic copy by email. The research was conducted in accordance with the journal’s ethical guidelines. All the participation was voluntary. The authors declare that the work described was original research that has not been published previously, and not under considerations for publication elsewhere, in whole or in part.