Acknowledgements
First and above all, I praise God, the almighty for providing me this opportunity
and granting me the capability to proceed successfully.
I feel very blessed to have the opportunity to study at Stony Brook University.
During these years, I received tremendous help and support from many individuals,
to whom I want to express my sincere thanks here.
I would like to express my deepest gratitude to my esteemed advisor, Prof.
Hong Qin, for accepting me as a Ph.D student. Your warm encouragement, thoughtful
guidance and critical comments, provided me an excellent atmosphere for doing
research.