This dissertation concludes my four years work as a PhD candidate in Nanyang Technological University. It was only after starting my PhD, did I begin to understand "Life is complicated". But one day when you look back you will realize that what was frustration before has turned into unforgettable memory. I would not be able to finish this thesis without the generous help and support from many people. First of all, I would like to express my innermost appreciations to my supervisors, Professor Sun Handong and Professor Gagik G. Gurzadyan. Without their continuous support and encouragement, I will not be able to complete my PhD project. Professor Gurzadyan is not only my mentor, but also a good friend in life. He trained me a critical way of thinking rather than only experimental skills. Professor Sun taught me the importance of integrity in academia, which always reminds me to check myself according to the standard of a qualified researcher. Besides, Professor Maria-Elisabeth Michel-Beyerle has also provided me with much guidance and enlightening discussions, for whom I would like to give my special and sincere appreciation. Next, I want to extend my truthful thanks to my collaborators, including Dr.