Funding for this research was provided by:
the National Aerospace Science Foundation of China (2016ZF53061)
the National Natural Science Foundation of China (11204241, 61601375)
the Northwestern Polytechnical University scientific research allowance (G2015KY0302)
the Natural Science Basic Research Plan in Shaanxi Province of China (2017JM1009)
the Fundamental Research Funds for the Central Universities (3102017jghk02004)