【導(dǎo)讀】隨著汽車的不斷普及，特別是中國(guó)汽車市場(chǎng)的不斷擴(kuò)大，由汽車帶來(lái)的一系列問題一一顯露，本文介紹的防撞報(bào)警系統(tǒng)為汽車的倒車報(bào)警裝置的研究提供了一些可行性方案。本文設(shè)計(jì)的基于單片機(jī)超聲波測(cè)距儀汽車防撞系統(tǒng)采用STC89C52為控制中心，超聲波測(cè)距儀完成對(duì)距離的檢測(cè)，測(cè)出距離以后將數(shù)據(jù)交給單片機(jī)處理運(yùn)算，距離的值可以通過按鍵設(shè)置，設(shè)定值的大小通過數(shù)碼管顯示出來(lái)，當(dāng)測(cè)定的距離小于設(shè)定值的時(shí)候，STC89C52便發(fā)出控制指令控制蜂鳴器發(fā)出報(bào)警聲，從而達(dá)到報(bào)警防撞的目的。由于超聲波測(cè)距系統(tǒng)具有不接觸，受外界干擾較少的優(yōu)點(diǎn)，所以在汽車的倒車技術(shù)研制方面得到了很廣泛的應(yīng)用。所以，超聲波測(cè)距技術(shù)在空氣測(cè)距的特殊環(huán)境下有廣泛的應(yīng)用。本設(shè)計(jì)包括硬件設(shè)計(jì)和軟件設(shè)計(jì)兩部分。電路結(jié)構(gòu)可劃分為：超聲波傳感器、蜂鳴器、單片機(jī)控制電路。硬件包括單片機(jī)、輸入/輸出設(shè)備、以及外圍應(yīng)用電路等組

　　

【正文】 as sacrificed. The American edition uses the framework of the Empress Dowager in her senior years reminiscing at the beginning and the end of each episode, hinting at what39。s to e and recapping the key points. This device, not used in the original, is culturally understandable but artistically mediocre. What puzzles me is the two new songs for the opening and end credits. They were written in English, but sung by Chinese with an unfortable accent. They were obviously designed to appeal to an Englishspeaking base, but do not jibe with the Chinese dialogue. Speaking of the dialogue, the English translation, picked apart by some Chinese, is too literal for my taste. I can imagine a typical American hit by a flurry of royal ranks, addresses and greetings, even multiple names and titles for the same person. The first half hour must be a swamp to wade through, very much like my experience of getting through a Tolstoy tome with its endless inflections of names transliterated into lengthy Chinese. I see the choice of verbatim translation as an effort for conveying exotica. It is fairly petent, with no error that I could detect, but fails to rise above words or capture the essence of the language. A cultural product usually crosses over to a foreign territory first by an emphasis on the monalities. But whether inside or outside China, the temptation to sell it for the differences is just too great. Sure, the sumptuous sets and costumes are a big attraction, but the narrative technique has bee－h(huán)ow shall I put it?－a bit anglicized, which is necessary for cultural export. Judging by the responses, this legend, which, contrary to the claim of the English trailer, is totally fictitious, has departed from China but not yet landed on American shores. I am a big fan of Ralph Waldo Emerson39。s essay titled SelfReliance. If you39。ve not yet read it, I strongly encourage you to do so. In this essay, the venerable Emerson talks about eschewing the trappings of society and finding one39。s own path. He urges the reader to find rectitude and lead a moral life. He professes that, only by being self reliant, as opposed to relying on the government and being dictated to by society, can one begin leading a decent and purposeful life. He avers that such a life is the only life worth living. I agree with him. This essay was written during a time of social upheaval in America, and it is rather odd that Emerson authored it, as he was a part of the upper crust of society at the time. It just so happened that he looked around him, at the indolence and the wantonness of the people in his circle。 he wondered how in the world he came to belong there. Indeed his penning and publishing this essay caused his exmunication from high society and also caused him a lot of legal trouble. The legal trouble came as a result of the fact that he was speaking out against the government. I like to reference such texts from time to time as an example both of the fact that history does repeat itself and that this world is not so big that what applies to one society does not in any way touch another society. On a much smaller scale,Emerson39。s essay affects me very deeply. Not as an urging to bee self reliant – I39。m nothing if not that! In his text he expounds on the idea that one must give their life a purpose. And that is the true topic of this entry. These last four years have been so easy: teach for a grand total of six hours a week, and the rest of my time is mine. Since I39。ve been here I have been tasked with nothing more challenging than learning my students39。 names and figuring out what to do with them for the brief time each week that I stand in front of them. I do not consider the challenges of learning to live here part of a purposeful life. I consider those issues existential in nature. One of the problems with my life in America was that I felt it had no purpose. I went to work every day and even did what I could to make my colleagues39。 work lives easier, but I simply could not digest the fact that that was my sole purpose in life. With no family to support, I was the sole beneficiary of my employment: the paycheck, the benefits, the incentives and the rewards were mine alone. Not much of a purpose in being selfserving, is there? While I was a student, I felt I was leading a purposeful life. Learning new things, broadening my horizons, expanding my life experiences all gave my life a zip and drive that I had not felt since being in survival mode when my kids were small. After graduating college I felt oddly deflated… but by then, China was on my horizon.21