Affiliation: | 1. School of Jet Propulsion , Beihang University , Beijing, 100191, P.R. China;2. Department of Mathematics and Physical Sciences, College of Engineering, Mathematics and Physical Sciences , University of Exeter , Exeter, EX4 4QF, UK lj249@exeter.ac.uk;4. Department of Mathematics and Physical Sciences, College of Engineering, Mathematics and Physical Sciences , University of Exeter , Exeter, EX4 4QF, UK;5. School of Jet Propulsion , Beihang University , Beijing, 100191, P.R. China |