In this thesis writing process, to be particularly grateful to my guidance teacher guidance and supervision, without the teacher's help there will be no today's paper. The journey of study is hard, but it is also happy. In this process, Mr. Liang always strict requirements of me, not the slightest sloppy, for me some problems, he is always able to put forward targeted insights, at the same time he paymore attention to my self-study ability to train.