Funding for this research was provided by:
National Natural Science Foundation of China (CN) (61572300)
Natural Science Foundation of Shandong Province in China (ZR2014FM001)
Taishan Scholar Program of Shandong Province in China (TSHW201502038)
SDUST Excellent Teaching Team Construction Plan (JXTD20160512)
Shandong Province Higher Educational Science & Technology Program (J14LN79)