Funding for this research was provided by:
Aeronautical Science Foundation of China (20155896025)
Article History
Received: 26 December 2018
Revised: 5 April 2019
Accepted: 26 May 2019
First Online: 4 June 2019
Compliance with Ethical Standards
:
: The authors declare that there are no conflicts of interest regarding the publication of this paper.
: No data were used to support this study.