Funding for this research was provided by:
National Natural Science Foundation of China (61872297)
Seed Foundation of Innovation and Creation for Graduate Students (ZZ2018170, ZZ2018235)
China National Training Programs of Innovation and Entrepreneurship for Undergraduates (201710699330)
Program of Peak Experience of Northwestern Polytechnical University (2016)
Article History
Received: 8 October 2018
Accepted: 1 April 2019
First Online: 8 April 2019