ABSTRACT
This book is the first collection of my papers published in China. It is my honor that the book is published by the Commercial Press. I had decided to take this opportunity to review and revise these papers, but the time-consuming activities of daily life hinder me from doing this. Ms. Ma Dongmei, the editor of this book, has been dedicated to this work since October 2012 and has shown the greatest patience regarding my delay in proofreading. I would like to express my most sincere gratitude and respect to her.
