Wang, W. G.
Li, X. Y.
Liu, T.
Funding for this research was provided by:
the National Natural Science Foundation of China (11604286)
Shaanxi Provincial Natural Science Foundation (15JK1833)
Special project of Yan’an university institute of material physics research and High-level University Construction Special Program of Shaanxi Province (Physics-2012SXTS05)
Yan’an University National Natural Science Foundation (YD2015-07,YD2009-2,YDBK2014-01)
the Shanxi Provincial College students’ innovative projects (1280)