Wang, Q. T.
Li, R. R.
Zhou, X. Z.
Li, J.
Lei, Z. Q.
Funding for this research was provided by:
Programme for Changjiang Scholars and Innovative Research Team in University (IRT_15R56)
Foundation of Northwest Normal University (NWNU-LKQN-13-5)
Programme for Colleges and Universities in Gansu Province (2014A-011)