Funding for this research was provided by:
National Natural Science Foundation of China (81371797)
the key projects of Natural Science Research of Anhui Education Department (KJ2016A248 and KJ2012A152)
the Provincial quality project of China (201610366067)
Received: 9 November 2017
Accepted: 2 February 2018
First Online: 10 February 2018
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