【導(dǎo)讀】作復(fù)雜，對(duì)技術(shù)人員要求較高，而且不具有實(shí)時(shí)性。迫切需要各種方法簡(jiǎn)單，準(zhǔn)。本文介紹了一種氣體泄漏超聲檢測(cè)系統(tǒng),在分析小孔氣體。泄漏產(chǎn)生超聲波的原理的基礎(chǔ)上,闡述了該檢測(cè)系統(tǒng)的原理及設(shè)計(jì)方案。能對(duì)各種壓力容器的孔隙泄漏所產(chǎn)生的微弱超聲信號(hào)進(jìn)行精確檢測(cè)。檢測(cè)及泄漏量的估算。通過(guò)超聲波檢測(cè)，正確地判斷和定位產(chǎn)生泄漏位置，對(duì)于。提高企業(yè)的生產(chǎn)效率，節(jié)約能源，確保安全具有重大意義。空氣中傳播具有很強(qiáng)的方向性。電路；數(shù)字電路由單片機(jī)和LCD、鍵盤等外圍設(shè)備組成。信號(hào)的強(qiáng)度與流速；另一路通過(guò)降頻轉(zhuǎn)化為可聽(tīng)聲，從而實(shí)現(xiàn)檢測(cè)的目的。

　　

【正文】 大電路，其中包含了兩級(jí)放大，第一級(jí)放大 100 倍，第二級(jí)放大 10 倍，它們是用電容耦合而成的。輸出的波形為5 伏，頻率為 40K 的正弦波； （ 5）通過(guò)放大器后，信號(hào)進(jìn)入帶通濾波器，輸出波形的中心頻率為 40K，帶寬為 38K 至 40K； （ 6） 該信號(hào)進(jìn)入精密檢波電路，精密檢波電路的作用是將正弦波轉(zhuǎn)變?yōu)殡妷簽? 伏 的直流信號(hào)； （ 7） 最后信號(hào) A/D 轉(zhuǎn)換電路進(jìn)行 AD 采樣。 （ 8） 第二線路的測(cè)試：由本振電路產(chǎn)生頻率為 37K 的多諧振蕩波； （ 9） 在端口 1輸入頻率為 3842K的正弦波并與 37K的多諧振蕩波進(jìn)行混頻，混頻后 進(jìn)入低通濾波器后，得到頻率 03K 的信號(hào)； （ 10） 最后信號(hào)進(jìn)入音頻功放電路，喇叭口處產(chǎn)生響聲，此完成整個(gè)調(diào)試過(guò)程。 6 結(jié)論 本文設(shè)計(jì)和制作了氣體泄漏超聲波檢測(cè)系統(tǒng)，該電路主要以性能穩(wěn)定、簡(jiǎn)單實(shí)用為目的，整體制作符合要求。 通過(guò)概述使大家充分了解了該檢測(cè)系統(tǒng)的原理與功能。從摘要和引言部分概要介紹了其可靠性和實(shí)用性。第一章介紹了氣體泄漏檢測(cè)方案的選擇和論證，從絕對(duì)壓力法、壓差法、超聲波檢測(cè)法相比較中，選出最佳方法；第二章介紹泄漏檢測(cè) 的設(shè)計(jì)原理，從對(duì)氣體泄漏產(chǎn)生一定頻率的聲波現(xiàn)象中發(fā)現(xiàn)了存在有超聲波，通過(guò)對(duì)超聲波的檢測(cè)來(lái)判斷泄漏的確切位置，并且從數(shù)學(xué)的角度分析了聲壓與泄漏量的關(guān)系；第三章詳細(xì)介紹超聲檢測(cè)電路設(shè)計(jì)原理與各單元電路的設(shè)計(jì)，從系統(tǒng)原理的角度得出系統(tǒng)分為模擬和數(shù)字兩部分；第四、五章介紹了軟件設(shè)計(jì)與電路調(diào)試過(guò)程。 通過(guò)本次電路的制作，我對(duì)氣體泄漏超聲檢測(cè)系統(tǒng)原理有了進(jìn)一步的了解，在氣體泄漏的分析中對(duì)超聲波檢測(cè)產(chǎn)生了濃厚的興趣，提高了科學(xué)的分析和運(yùn)用能力。 本電路雖然已完成實(shí)際制作，并且符合要求，但也存在許多需要完善的地方，由于本人 水平有限，因此對(duì)其中的原理和實(shí)際操作方法有待深入的學(xué)習(xí)研究和提高。文中有不足之處懇請(qǐng)各位老師加以指導(dǎo)，本學(xué)生衷心感謝。 謝 辭 本文是在導(dǎo)師晉良念老師悉心指導(dǎo)和鼓勵(lì)下完成的。論文的選題、具體工作和撰寫過(guò)程都凝聚著導(dǎo)師的心血和汗水。晉良念老師淵博的知識(shí)，嚴(yán)謹(jǐn)?shù)闹螌W(xué)態(tài)度和一絲不茍的工作作風(fēng)給我留下了深深的印象，使我受益匪淺。在設(shè)計(jì)、制作到論文的完成過(guò)程中，晉良念老師盡量為我提供實(shí)踐基地和耐心指導(dǎo)，并且在生活上給予了極大的關(guān)心和幫助。在此向晉良念老師表示衷心的感謝和崇高的敬禮。 最后感謝桂林電子科技大學(xué)的培 養(yǎng)，感謝所有教過(guò)和沒(méi)教過(guò)我課的老師。衷心感謝在百忙中抽空參加論文評(píng)審的各位老師，感謝他們?yōu)楸疚母冻龅男燎趧趧?dòng)。另外還得感謝辛苦培養(yǎng)我的父母，感謝他們的培養(yǎng)。 參考文獻(xiàn) [1] 王化祥，張淑英 .傳感器原理及應(yīng)用 [M].天津：天津大學(xué)出版社， . [2]于亞非 .用超聲波傳感器檢測(cè)氣體泄漏 [J].儀器與未來(lái)， 1992(8). [3]李光海，王勇等 .基于聲發(fā)射技術(shù)的管道泄漏檢測(cè)系統(tǒng) [J].自動(dòng)化儀表， [4]李群芳 .單片微型計(jì)算機(jī)與接口技術(shù) [M].北京：電子工業(yè)出版社， 2021. [5]李進(jìn)，陳會(huì)倉(cāng)等 .氣體泄漏超聲波檢測(cè)裝置 [J]. 工業(yè)儀表與自動(dòng)化裝置， 1996， (5). [6]龔其春，葉騫 .新型氣體泄漏超聲檢測(cè)系統(tǒng)的研究與設(shè)計(jì) [J].電子技術(shù)應(yīng)用， 2021， 3 [7] 袁易全 ,黃建人 . 高靈敏超聲檢漏儀的研究 [M].東南大學(xué)學(xué)報(bào) ， 1989 [8] 李建藩 .氣壓傳動(dòng)系統(tǒng)動(dòng)力學(xué)廣州 [M].華南理工大學(xué)出版社 ， 1991 [9]ATMEL Microcontroller with 8K Bytes Flash AT89C52. [10]Donald Circuit Analysis and Design(Second edition). Published by the McGrawHill panies,2021. And what numberless and powerful causes tend to destroy these rare natures! What causes? In the first place there are their own virtues, their courage, temperance, and the rest of them, every one of which praise w orthy qualities (and this is a most singular circumstance) destroys and distracts from philosophy the soul which is the possessor of them. That is very singular, he replied. Then there are all the ordinary goods of life beauty, wealth, strength, rank, and great connections in the State you understand the sort of things these also have a corrupting and distracting effect. I understand。 but I should like to know more precisely what you mean about them. Grasp the truth as a whole, I said, and in the right way。 you will then have no difficulty in apprehending the preceding remarks, and they will no longer appear strange to you. And how am I to do so? he asked. Why, I said, we know that all germs or seeds, whether vegetable or animal, when they fail to meet with proper nutriment or cl imate or soil, in proportion to their vigour, are all the more sensitive to the want of a suitable environment, for evil is a greater enemy to what is good than what is not. Very true. There is reason in supposing that the finest natures, when under alien conditions, receive more injury than the inferior, because the contrast is greater. Certainly. And may we not say, Adeimantus, that the most gifted minds, when they are illeducated, bee preeminently bad? Do not great crimes and the spirit of pure evil spring out of a fulness of nature ruined by education rather than from any inferiority, whereas weak natures are scarcely capable of any very great good or very great evil? There I think that you are right. And our philosopher follows the same analogy he is like a plant which, having proper nurture, must necessarily grow and mature into all virtue, but, if sown and planted in an alien soil, be es the most noxious of all weeds, unless he be preserved by some divine power. Do you really think, as people so often say, tha t our youth are corrupted by Sophists, or tha t private teachers of the art corrupt them in any degree worth speaking of ? Are not the public who say these things the greatest of all Sophists? And do they not educate to pe rfection young and old, men and women alike, and fashion them after their own hearts? When is this acplished? he said. When they meet together, and the world sits down at an assembly, or in a court of law, or a theatre, or a camp, or in any other popular resort, and there is a great uproar, and they praise some things which are being said or done, and blame other things, equally exaggerating both, shouting and clapping their hands, and the echo of the roc ks and the place in which they are assembled redoubles the sound of the praise or blame at such a time will not a young man39。s heart, as they say, leap within him? Will any private training enable him to stand firm against the overwhelming flood of popular opinion? or will he be carried away by the stream? Will he not have the notions of good and evil which the public in general have he will do as they do, and as they are, such will he be? Yes, Socrates。 necessity will pel him. And yet, I said, there is a still greater necessity, which has not been mentioned. What is that? The gentle force of attainder or confiscation or death which, as you are aware, these new Sophists and educators who are the public, apply when their words are powerless. Indeed they do。 and in right good earnest. Now what opinion of any other Sophist, or of any private person, can be expected to overe in such an unequal contest? None, he replied. No, indeed, I said, even to make the attempt is a great piece of folly。 there neither is, nor has been, nor is ever likely to be, any different type of character which has had no other training in virtue but that which is supplied by public opinion I speak, my friend, of human virtue only。 what is more than human, as the proverb says, is not inc luded: for