致谢：感谢那些支持我完成论文的人

As I approach the completion of my thesis, I wish to express my gratitude to those who have supported and encouraged me to reach this point. I am thankful for their encouragement and companionship throughout my university life.

First and foremost, I would like to express my gratitude to my supervisor, Professor Xie Gaofu. Over the past four years, Professor Xie has provided me with attentive guidance and support, allowing me to gain invaluable knowledge in my field of study. Moreover, he has helped me identify the areas that I need to improve upon in my future academic research.

Lastly, I would like to thank my parents and friends for their unwavering support and companionship during my studies. Their encouragement has been a driving force that has helped me to overcome challenges and reach this point in my academic journey.