First, I would like to express my grateful thanks and sincere respect to my supervisor, Dr. Mo Li. I had no concept of research when I enrolled in this Ph.D career four years ago. During these years, Dr. Mo Li helped me develop classic research taste, rigorous research attitude, and standard research logic. I learned a lot from him, not only about research, but also about the bravery when I have to face difficulties, the resilience when I have to take paper rejections, and the optimism when I have to accept failures. Ph.D study is not easy, fortunately, I work with the best supervisor.Second, I would like to thank my mother and my father. They spent all their energy during the past thirty years protecting a warm family where I can grow up, get mature and learn responsibility. They act physical examples to explain me the meaning of diligence, integrity and gratitude, which set me up from the inside so that I can approach to complete the Ph.D study. In particular, I want to thank my mother. She does not talk too much, but the way she works always inspires me to keep moving forward.