Firstly,the configuration of primary-side feedback AC/DC converter is described and its feedback voltage waveform is detailedly analyzed.

On the basis of the system and cybernetics, a population system is regarded as a multiple feedback system.

A Study of the Effects of Peer Feedback on Writing by Chinese EFL Learners at Different Proficiency Levels;

So this paper presents the functions,using methods and principles of peer feedback in college writing class so as to change teachers and students attitude towards peer feedback,incite students writing interest,empower students writing and innovation ability and inspire college English writing instruction.

The results of a questionnaire survey and follow-up interviews show that advanced learners of English have strong inclination to and a high rate of accuracy in peer feedback;students English writing proficiency influences their peer feedback ability;more attention is paid to language than to content and structure in peer feedback.