1. Ph.D. Student, Research Center of Small Sample Technology, Beijing Univ. of Aeronautics and Astronautics, Beijing 100191, China (corresponding author).
2. Professor, Research Center of Small Sample Technology, Beijing Univ. of Aeronautics and Astronautics, Beijing 100191, China.
3. Lecturer, Research Center of Small Sample Technology, Beijing Univ. of Aeronautics and Astronautics, Beijing 100191, China.