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ii Acknowledgements I express my sincere appreciation and gratitude to my major professor, Dr. Todd F. Shupe, for his guidance, advice, insight, availability and support from the beginning of my program to the completion of this thesis. Special thanks to Dr. Chung Y. Hse for his guidance on the experimental design and kind assistance throughout the duration of this project. His profound insight into research problems deeply impressed me. I would like to express my gratitude to Dr. Niels deHoop for his advice on my experiments and thesis. I also would like to express appreciation to Dr. Thomas Eberhardt for offering kind and helpful suggestions in preparation of the experiment. Appreciation is also extended to Ms. Donna Edwards and Ms. Karen Reed who gave me support and suggestions during the experiments. I would like to show my deepest gratitude to my parents and my girlfriend. Their support and encouragement is my treasure