齒輪軸機(jī)械加工工藝及鉆4孔專用夾具設(shè)計（全套設(shè)計含CAD圖紙）,齒輪軸,機(jī)械,加工,工藝,專用,夾具,設(shè)計,全套,cad,圖紙 畢業(yè)設(shè)計(論文)外文資料翻譯 系　　部： 機(jī)械工程系 專 業(yè)： 機(jī)械工程及自動化 姓 名： 徐東青 學(xué) 號： 0501510144 外文出處： Electromechanical Integration and The Development of Technology Trends 附 件： 1.外文資料翻譯譯文；2.外文原文。 指導(dǎo)教師評語： 簽名： 年 月 日 附件1：外文資料翻譯譯文 機(jī)電一體化技術(shù) 一、機(jī)電一體化技術(shù)發(fā)展歷程及其趨勢 自電子技術(shù)一問世，電子技術(shù)與機(jī)械技術(shù)的結(jié)合就開始了，只是出現(xiàn)了半導(dǎo)體集成電路，尤其是出現(xiàn)了以微處理器為代表的大規(guī)模集成電路以后，機(jī)電一體化技術(shù)之后有了明顯進(jìn)展，引起了人們的廣泛注意。 (一)機(jī)電一體化的發(fā)展歷程 1.數(shù)控機(jī)床的問世，寫下了機(jī)電一體化歷史的第一頁； 2.微電子技術(shù)為機(jī)電一體化帶來勃勃生機(jī)； 3.可編程序控制器、電力電子等的發(fā)展為機(jī)電一體化提供了堅強(qiáng)基礎(chǔ)； 4.激光技術(shù)、模糊技術(shù)、信息技術(shù)等新技術(shù)使機(jī)電一體化躍上新臺階。 (二)機(jī)電一體化發(fā)展趨勢 1.光機(jī)電一體化。一般的機(jī)電一體化系統(tǒng)是由傳感系統(tǒng)、能源系統(tǒng)、信息處理系統(tǒng)、機(jī)械結(jié)構(gòu)等部件組成的。因此，引進(jìn)光學(xué)技術(shù)，實現(xiàn)光學(xué)技術(shù)的先天優(yōu)點是能有效地改進(jìn)機(jī)電一體化系統(tǒng)的傳感系統(tǒng)、能源(動力)系統(tǒng)和信息處理系統(tǒng)。光機(jī)電一體化是機(jī)電產(chǎn)品發(fā)展的重要趨勢。 2.自律分配系統(tǒng)化——柔性化。未來的機(jī)電一體化產(chǎn)品，控制和執(zhí)行系統(tǒng)有足夠的冗余度，有較強(qiáng)的柔性，能較好地應(yīng)付突發(fā)事件，被設(shè)計成自律分配系統(tǒng)。在自律分配系統(tǒng)中，各個子系統(tǒng)是相互獨立工作的，子系統(tǒng)為總系統(tǒng)服務(wù)，同時具有本身的自律性，可根據(jù)不同的環(huán)境條件作出不同反應(yīng)。其特點是子系統(tǒng)可產(chǎn)生本身的信息并附加所給信息，在總的前提下，具體行動是可以改變的。這樣，既明顯地增加了系統(tǒng)的適應(yīng)能力(柔性)，又不因某一子系統(tǒng)的故障而影響整個系統(tǒng)。 3.全息系統(tǒng)化——智能化。今后的機(jī)電一體化產(chǎn)品全息特征越來越明顯，智能化水平越來越高。這主要收益于模糊技術(shù)、信息技術(shù)(尤其是軟件及芯片技術(shù))的發(fā)展。除此之外，其系統(tǒng)的層次結(jié)構(gòu)，也變簡單的從上到下的形勢而為復(fù)雜的、有較多冗余度的雙向聯(lián)系。 4.生物一軟件化—仿生物系統(tǒng)化。今后的機(jī)電一體化裝置對信息的依賴性很大，并且往往在結(jié)構(gòu)上是處于靜態(tài)時不穩(wěn)定，但在動態(tài)(工作)時卻是穩(wěn)定的。這有點類似于活的生物：當(dāng)控制系統(tǒng)(大腦)停止工作時，生物便死亡，而當(dāng)控制系統(tǒng)(大腦)工作時，生物就很有活力。仿生學(xué)研究領(lǐng)域中已發(fā)現(xiàn)的一些生物體優(yōu)良的機(jī)構(gòu)可為機(jī)電一體化產(chǎn)品提供新型機(jī)體，但如何使這些新型機(jī)體具有活的生命還有待于深入研究。這一研究領(lǐng)域稱為生物——軟件或生物——系統(tǒng)，而生物的特點是硬件(肌體)——軟件(大腦)一體，不可分割?？磥?，機(jī)電一體化產(chǎn)品雖然有向生物系統(tǒng)化發(fā)展趨，但有一段漫長的道路要走。 5.微型機(jī)電化——微型化。目前，利用半導(dǎo)體器件制造過程中的蝕刻技術(shù)，在實驗室中已制造出亞微米級的機(jī)械元件。當(dāng)將這一成果用于實際產(chǎn)品時，就沒有必要區(qū)分機(jī)械部分和控制器了。屆時機(jī)械和電子完全可以融合，機(jī)體、執(zhí)行機(jī)構(gòu)、傳感器、CPU等可集成在一起，體積很小，并組成一種自律元件。這種微型機(jī)械學(xué)是機(jī)電一體化的重要發(fā)展方向。 二、典型的機(jī)電一體化產(chǎn)品 機(jī)電一體化產(chǎn)品分系統(tǒng)(整機(jī))和基礎(chǔ)元、部件兩大類。典型的機(jī)電一體化系統(tǒng)有：數(shù)控機(jī)床、機(jī)器人、汽車電子化產(chǎn)品、智能化儀器儀表、電子排版印刷系統(tǒng)、CAD／CAM系統(tǒng)等。典型的機(jī)電一體化元、部件有：電力電子器件及裝置、可編程序控制器、模糊控制器、微型電機(jī)、傳感器、專用集成電路、伺服機(jī)構(gòu)等。這些典型的機(jī)電一體化產(chǎn)品的技術(shù)現(xiàn)狀、發(fā)展趨勢、市場前景分析從略。 三、我國發(fā)展機(jī)電一體化面臨的形勢和任務(wù) 機(jī)電一體化工作主要包括兩個層次：一是用微電子技術(shù)改造傳統(tǒng)產(chǎn)業(yè)，其目的是節(jié)能、節(jié)材，提高工效，提高產(chǎn)品質(zhì)量，把傳統(tǒng)工業(yè)的技術(shù)進(jìn)步提高一步；二是開發(fā)自動化、數(shù)字化、智能化機(jī)電產(chǎn)品，促進(jìn)產(chǎn)品的更新?lián)Q代。 (一)我國機(jī)電一體化工作面臨的形勢 1. 我國用微電子技術(shù)改造傳統(tǒng)工業(yè)的工作量大而廣，有難度。 2. 我國用機(jī)電一體化技術(shù)加速產(chǎn)品更新?lián)Q代，提高市場占有率的呼聲高，有壓力。 3. 我國用機(jī)電一體化產(chǎn)品取代技術(shù)含量和附加值低，耗能、耗水、耗材高、污染、擾民產(chǎn)品的責(zé)任重，有意義。在我國工業(yè)系統(tǒng)中，能耗、耗水大戶，對環(huán)境污染嚴(yán)重的企業(yè)還占相當(dāng)大的比重。近年來我國的工業(yè)結(jié)構(gòu)、產(chǎn)品結(jié)構(gòu)雖然幾經(jīng)調(diào)整，但由于多種原因，成效一直不夠明顯。這里面固然有上級領(lǐng)導(dǎo)部門的政出多門問題，有企業(yè)的故土難離，死守故業(yè)問題，但不可否認(rèn)也有優(yōu)化不出理想的產(chǎn)業(yè)，優(yōu)選不出中意的產(chǎn)品問題。上佳的答案早就擺在了這些企業(yè)的面前，這就是發(fā)展機(jī)電一體化，開發(fā)和生產(chǎn)有關(guān)的機(jī)電一體化產(chǎn)品。機(jī)電一體化產(chǎn)品功能強(qiáng)、性能好、質(zhì)量高、成本低，且具有柔性，可根據(jù)市場需要和用戶反映時產(chǎn)品結(jié)構(gòu)和生產(chǎn)過程做必要的調(diào)整、改革，而無須改換設(shè)備。這是解決機(jī)電產(chǎn)品多品種、少批量生產(chǎn)的重要出路。同時，可為傳統(tǒng)的機(jī)械工業(yè)注入新鮮血液，帶來新的活力，把機(jī)械生產(chǎn)從繁重的體力勞動中解脫出來，實現(xiàn)文明生產(chǎn)。 另外，從市場需求的角度看，由于我國研制、開發(fā)機(jī)電一體化產(chǎn)品的歷史不長，差距較大，許多產(chǎn)品的品種、數(shù)量、檔次、質(zhì)量都不能滿足需求，每年進(jìn)口量都比較大，因此亟需發(fā)展。 (二) 我國機(jī)電一體化工作的任務(wù) 我國在機(jī)電一體化方面的任務(wù)可以概括為兩句話：一句話是廣泛深入地用機(jī)電一體化技術(shù)改造傳統(tǒng)產(chǎn)業(yè)；另一句話是大張旗鼓地開發(fā)機(jī)電一體化產(chǎn)品，促進(jìn)機(jī)電產(chǎn)品的更新?lián)Q代?？偟哪康氖谴龠M(jìn)機(jī)電一體產(chǎn)業(yè)的形成、為我國產(chǎn)業(yè)結(jié)構(gòu)和產(chǎn)品結(jié)構(gòu)調(diào)整作貢獻(xiàn)。 總之，機(jī)電一體化技術(shù)既是振興傳統(tǒng)機(jī)電工業(yè)的新鮮血液和源動力，又是開啟我國機(jī)電行業(yè)產(chǎn)品結(jié)構(gòu)、產(chǎn)業(yè)結(jié)構(gòu)調(diào)整大門的鑰匙。 四、我國發(fā)展機(jī)電一體化的對策 (一)加強(qiáng)統(tǒng)籌安排，協(xié)調(diào)發(fā)展計劃 目前，我國從事機(jī)電一體化研究開發(fā)及生產(chǎn)的單位很多。各自都有一套自己的發(fā)展策略。各單位的計劃由于受各自立足點、著眼點的限制，難免只考慮局部利益，各主管部門的有關(guān)計劃和規(guī)劃，也有統(tǒng)一考慮不足，統(tǒng)籌安排不夠的問題，同時缺少綜觀全局的有權(quán)威性的發(fā)展計劃和戰(zhàn)略規(guī)劃。因此，建議各主管部門責(zé)成有關(guān)單位在進(jìn)行深入調(diào)查研究、科學(xué)分析的基礎(chǔ)上，制定出統(tǒng)管全局的機(jī)電一體化研究、開發(fā)、生產(chǎn)計劃和規(guī)劃，避免開發(fā)上重復(fù)，生產(chǎn)上撞車。 (二)強(qiáng)化行業(yè)管理，發(fā)揮協(xié)會作用 目前，我國機(jī)電一體化較熱，而按目前的行業(yè)劃分方法和管理體制，政出多門是難哆的。因此，我國有必要明確一個機(jī)電一體化行業(yè)的統(tǒng)管機(jī)構(gòu)，根據(jù)目前國家政治體制改革和經(jīng)濟(jì)體制改革的精神，以及機(jī)電一體化行業(yè)特點，我們建議，盡快加強(qiáng)北京機(jī)電一體化協(xié)會的建設(shè)，賦予其行業(yè)管理職能。協(xié)會要進(jìn)一步擴(kuò)大領(lǐng)導(dǎo)機(jī)構(gòu)——理事會的代表層面和復(fù)蓋面，要加強(qiáng)辦公室、秘書處的建設(shè)；要通過其精明干練的辦事機(jī)構(gòu)、經(jīng)濟(jì)實體，組織行業(yè)發(fā)展計劃、戰(zhàn)略規(guī)劃的擬制；指導(dǎo)行業(yè)布點布局的調(diào)整，進(jìn)行發(fā)展突破口的選擇，抓好重點工程的試點和有關(guān)項目的發(fā)標(biāo)、招標(biāo)工作…… (三)優(yōu)化發(fā)展環(huán)境、增大支持力度 優(yōu)化發(fā)展環(huán)境指通過宣傳群眾，造成一種社會上下、企業(yè)內(nèi)外都重視、支持機(jī)電一體化發(fā)展的氛圍，如盡快為外商到我國投資發(fā)展機(jī)電一體化產(chǎn)業(yè)提供方便；盡可能為興辦開發(fā)、生產(chǎn)機(jī)電一體化產(chǎn)品的高新技術(shù)企業(yè)開綠燈；盡力為開發(fā)、生產(chǎn)機(jī)電一體化產(chǎn)品調(diào)配好資源要素等。 增大支持力度，在技術(shù)政策上，要嚴(yán)格限制耗電、耗水、耗材高的傳統(tǒng)產(chǎn)品的發(fā)展，對未采用機(jī)電一體化技術(shù)落后產(chǎn)品限制強(qiáng)制淘汰；大力提倡用機(jī)電一體化技術(shù)對傳統(tǒng)產(chǎn)業(yè)進(jìn)行改造，對有關(guān)機(jī)電一體化技術(shù)對傳統(tǒng)產(chǎn)業(yè)乾地改造，對有關(guān)技術(shù)開發(fā)、應(yīng)用項目優(yōu)先立項、優(yōu)先支持，對在技術(shù)開發(fā)、應(yīng)用中做出貢獻(xiàn)的單位領(lǐng)導(dǎo)、科技人員進(jìn)行表彰獎勵等。 (四)突出發(fā)展重點，兼顧兩個層次 機(jī)電一體化產(chǎn)業(yè)復(fù)蓋面非常廣，而我們的財力、人力和物力是有限的，因此我們在抓機(jī)電一體化產(chǎn)業(yè)發(fā)展時不能面面俱到、平鋪直敘，而應(yīng)分清主次，大膽取舍，有所為，有所不為。要注意抓兩個層次上的工作。第一個層次是面上的工作，即用電子信息技術(shù)對傳統(tǒng)產(chǎn)業(yè)進(jìn)行改造，在傳統(tǒng)的機(jī)電設(shè)備上植入或嫁接上微電子(計算機(jī))裝置，使機(jī)械和電子技術(shù)在淺層次上結(jié)合。第二個層次是提高工作，即在新產(chǎn)品設(shè)計之初，就把機(jī)械與電子統(tǒng)一起來進(jìn)行考慮，使機(jī)械與電子密不可分，深度結(jié)合，生產(chǎn)出來的新產(chǎn)品起碼正做到機(jī)電一體化。 結(jié)束語：本論文在各位老師的悉心指導(dǎo)和嚴(yán)格要求下已完成。在學(xué)習(xí)和生活期間，也始終感受著導(dǎo)師的精心指導(dǎo)和無私的關(guān)懷，我受益匪淺。在此向各位老師表示深深的感謝和崇高的敬意。不積跬步何以至千里，本設(shè)計能夠順利的完成，也歸功于各位任課老師的認(rèn)真負(fù)責(zé)，使我能夠很好的掌握和運(yùn)用專業(yè)知識，并在設(shè)計中得以體現(xiàn)。同時我在網(wǎng)上也搜集了不少資料，才使我的畢業(yè)論文工作順利完成。在此向?qū)W院工程系的全體老師表示由衷的謝意。 附件2：外文原文 Electromechanical Integration 1. electromechanical integration and the development of technology trends Since an electronic technology birth of electronic technology and mechanical technology integration began， only a semiconductor integrated circuit， particularly in a microprocessor representative of the large-scale integrated circuits for the future， “mechatronics，” a technical after significant progress， and has attracted widespread attention. (A) mechanical-electrical integration， “the course of development 1. CNC machine tools come out， wrote “mechatronics，” the first page of history； 2. Microelectronic technology， “mechatronics''bring a great vitality； 3. PLC， “Power Electronics” for the development of “mechatronics” provide a firm foundation； 4. Laser technology， fuzzy technology， information technology and other new technologies to “mechanical and electrical integration，” a new and higher level. (B) mechanical-electrical integration， “the development trend 1. Integration of optical and electrical machinery. General mechanical and electrical integration system by sensing systems， energy systems， information processing systems， machinery， and other components of the structure. Therefore， the introduction of optical technology， the realization of the inherent advantages of optical technology is effective Improved mechanical-electrical integration system sensing system， energy (power) systems and information processing system. optical and electrical machinery integration is the development of mechanical and electrical products trend. 2. Systematic self-distribution - Flexible Future electromechanical integration products， and implementation of control systems are adequate “redundancy” and more “flexible” and can better deal with an emergency， is designed “self-distribution system.” Self-discipline in the distribution system， the various subsystems are independent of each other's work， the subsystem for system services， and has its own “self-discipline”， according to different environmental conditions react differently. Its characteristics are subsystem can generate its own information and additional information given in the overall premise， specific “action” can be changed. In this way， significantly increase the system's ability to adapt (flexible)， not because of the failure of a subsystem of the whole system. 3. Holographic systematic - intelligent. Future integration of mechanical and electrical products， “holographic” features more and more obvious， more and more high-level intelligence. This is mainly revenues in the fuzzy technology， information technology (especially software and chip technology) development. In addition， the hierarchical structure of the system， a simple change of “top-down” situation is complex， there is much more two-way link redundancy. 4. “Of a software” of the - Biomimetic systematic. Future integration of electrical and mechanical devices on the dependence of great information， and often the structure is in a “static” instability， but in a dynamic (work) when is stable. This is a bit like living biological: When control system (the brain) to stop work， then of “Death”， and when control system (brain) work， the biological vitality. Bionics research in the field of a number of organisms have been found good institutions can provide products for the electrical and mechanical integration of the new body， but how to live with these new body of “Life” has to be in-depth study. This field of study referred to as “biological - Software” or “biological - System”， and biological characteristics of the hardware (body) - Software (brain) one and indivisible. It seems， electromechanical integration of the products although there are more systematic development， but there is a long way to go. 5. MEMS of - miniaturization. At present， the semiconductor devices used in the manufacturing process of etching technology， in the lab has produced sub-micron mechanical components. When will this result for the actual product， there is no need to distinguish between the mechanical part and controller. Will be completely mechanical and electronic “integration”， and the body， the Executive Body， sensors， such as CPU can be integrated with the size of a small， and the formation of a self-regulatory components. This micro-mechanical integration of electromechanical important direction of development. Second， the typical electromechanical integration products Mechanical and electrical subsystems integration products (complete machine) and the foundation yuan， part two categories. Typical mechanical-electrical integration system: CNC machine tools， robotics， automotive electronic products， intelligent instrumentation， electronic publishing printing systems， CAD / CAM systems. Typical electromechanical integration yuan， components are: power electronic devices and devices， programmable logic controller， fuzzy controller， micro-motors， sensors， ASIC， servo institutions. These typical electromechanical integration of technical status quo and development trends， market analysis of (not quoted). Third， China's development “mechatronics” the situation and tasks facing Mechanical and electrical integration mainly include two levels: First， by using microelectronic technology to transform traditional industries， and its purpose is energy and materials to enhance efficiency， improve product quality， the traditional industries of technological advances in improving step two is to develop automated， digital ， intelligent mechanical and electrical products， and promote the upgrading of products. (A) China's “mechatronics” of the situation facing 1. China's microelectronics technology to transform traditional industries with the workload of large and broad， difficult 2. Electromechanical integration technology with China's accelerated product upgrading， enhancing the voice of the market share， pressure. 3. Electromechanical integration with China replaced by products of low technology content and added value， energy， water， supplies， pollution， disturbing product liability heavy and meaningful. China's industrial systems， energy consumption， water consumption big， serious environmental pollution enterprises also accounted for a fairly large proportion. In recent years China's industrial structure， product mix Although several adjustments， but for various reasons， lack of effectiveness has been obvious. This is a higher level inside leading departments from many doors， enterprises are “finding it hard to leave their native land”， “is entrenched industry”， but also optimize the undeniable not the ideal industry， the optimized no Italian products. The best answer long ago put these enterprises in the face， this is the development of mechanical and electrical integration， development and production of the electrical and mechanical integration products. Mechatronics product features strong， good performance， high-quality， low cost， and has a flexible， according to the needs of the market and reflect the user when the product mix and production process to do the necessary restructuring and reform， instead of switching equipment. This is the solution of mechanical and electrical products and more variety， the less important way to mass production. At the same time， for the traditional mechanical industries injection of fresh blood， bringing new vitality， and the heavy machinery production from the manual relieved to achieve civilized production. Furthermore， from the point of view of market demand， China's research and development of mechanical and electrical integration products with no long history， a big gap between the many varieties of product， quantity， grade， quality， can not meet the demand， larger than the annual import volume， much-needed development. (B) China's “mechatronics，” the task China's mechanical and electrical integration， the task can be summed up in two sentences: The first observation is extensively used electromechanical integration technology to transform traditional industries； Another observation is that the mechanical and electrical integration in a big way to develop products， and promote the upgrading of mechanical and electrical products. The overall goal is to promote the formation of mechanical and electrical integration industry for China's industrial structure and product mix adjustment and make contributions. In short， electromechanical integration technology is to revitalize traditional electromechanical industrial source of fresh blood and driving force， is to open China's electromechanical industry products， the industrial structure adjustment of the keys to the door. Fourth， China's development “mechatronics” Countermeasures (A) strengthen the co-ordination arrangements， coordinated development plan Currently， the country engaged in “mechatronics” research and development and production of many units. Each had a set of its own development strategy. The units in their plans because of the foothold， the focus of the restrictions， it is inevitable to consider only local interests， the competent departments of the project and planning， lack of a unified consider， and make enough issue， the lack of authoritative Looking at the overall development plans and strategic planning. It is therefore recommended that the competent departments instruct the relevant units of in-depth investigation and study and scientific analysis on the basis of the overall development of a unified management “mechatronics” research， development， production plans and programmes to avoid duplication of development， production crashes! (B) strengthen regulation of the industry， to play the “Association” role At present， China's “mechatronics” more heat， while the current industry breakdown methods and management system， “from many doors” is the difficult pyridoxine. Therefore， it is necessary to clarify our country a “mechatronics” industry's management body， according to the country's political and economic reforms the spirit， as well as mechanical and electrical integration industry characteristics， we propose that the Beijing as soon as possible to strengthen the construction of the Electrical and Mechanical Integration Association， given its industry management functions. “Association” We should further expand the leadership - the representatives of the Governing Council and the level of coverage， we must strengthen the Office of the Secretariat building； able to pass its smart offices， economic entities， organizations， “industry” development， strategic planning fiction； guidance layout layout of the industry adjustment， the starting point for the development of options， do a good job of the pilot and key projects of the issuing of the project， the tender exercise…… (C) Optimization development environment， increased support for the Optimization development environment that through propaganda among the masses， creating a community as a whole， both inside and outside the enterprise to support “the mechanical and electrical integration，” the atmosphere of development， such as China as soon as possible for foreign investors to invest in the development of “mechatronics” industry to provide convenient as possible for the establishment of development， production integration of mechanical and electrical products give the green light to high-tech enterprises； endeavour to develop， manufacture electromechanical integration products， such as the deployment of elements of good resources. Increase the intensity of support， technology policy， it is necessary to strictly limit the consumption of electricity， water， supplies high-traditional product development， did not use the mechanical and electrical integration of backward technology products restrictions mandatory elimination； strongly advocated using electromechanical integration on the traditional industries for the transformation of the electrical and mechanical integration technology to transform traditional industries dry on the technical development and application of project priority projects， and give priority support to the technical development and application of the unit to contribute to leadership， science and technology personnel of recognition incentives. (D) to highlight key development， take into account the “two levels” Mechatronics industries cover a very wide， and our financial， human and material resources are limited， so we grasp mechatronics industry development can not be exhaustive， Bengpuzhixu， it should distinguish between primary and secondary， bold choices， in order， selective. Attention should be paid to work on two levels. The first level is the “face” of work， namely the use of electronic information technology to transform traditional industries， in the traditional electromechanical devices implanted or grafted on Microelectronics (computer) devices， the “machinery” and “electronic” technology in the Jiancengci integrate. The second level is the “increase”， that is the beginning of the new product design， they “machinery” and “electronic” unified consideration， “machinery” and “electronic” inextricably linked， in-depth integration of the new production Products are at least do electromechanical integration. CONCLUSION: In this paper， in the careful guidance of teachers and strict requirements have been completed. Learning and life， will always feel the careful guidance of a mentor and selfless caring， I benefited. You are here to express our deep gratitude and lofty respect. Why not plot to step of a thousand miles， the smooth completion of the design， but also owe much to the datum related to the serious and responsible teacher， I can well understand and use our professional knowledge， and to be reflected in the design. At the same time， I collected a lot of online information before making my dissertation work smoothly. College of Engineering here to all teachers expressed heartfelt thanks.