I would like to express my gratitude and appreciation to my advisor, Dr. Yong Guan, for his patience, enthusiasm, immense knowledge, and efforts to help me through this whole process. I have received systematic and strict academic training under his guide, which are significant first steps in preparing for the professional career that I desire. I could not have imagined having a better mentor for my master's study. I would like to thank Dr. Daji Qiao and Dr. Goce Trajcevski for serving on my committee and providing me with valuable and insightful suggestions.In addition, I would like to thank my friends, the department faculty, and staff for making my time at Iowa State University a wonderful experience. I would also like to thank my family and friends for their support and encouragement and their continuous motivation for me to keep forging ahead. All of my lab mates are appreciated for help and concern about this project.