【正文】 he years has led to major improvements, Thus development of improved additives like antioxidants and viscosity index improves for engine oil has enabled routine servicing intervals to increase from 300 to 6000 to 12000 and development work has also resulted in improved lubricating oils and greases, and better brake again the contribution of automobile polymers and plastics has been very striking with the proportion of the total automobile derived from these materialsdashboard, steering wheel, seat padding and covering exceeding 40%.(4)Shelter, leisure and terms of shelter the contribution of modern synthetic polymers has been are tending to replace traditional building materials like wood because they are lighter, maintenancefree( are resistant to weathering and do not need painting).Other polymers, and polyurethanes, are important insulating materials for reducing heat losses and hence reducing energy and polymers have made a considerable impact on leisure activities with applications ranging from allweather artificial surfaces for athletic tracks, football pitches and tennis courts to nylon strings for racquets and items like golf balls and footballs made entirely from synthetic major advances in this sphere have been in colorfastness, ., resistance to the dye being washed out when the garment is developments in the discovery of modern synthetic dyes and the technology to “bond” them to the fiber have resulted in a tremendous increase in the variety of colors available to the fashion they now span almost every color and hue of the visible if a suitable shade is not available, structural modification of an existing dye to achieve this can readily be carried out, provided there is a satisfactory market for the product.(3) improvement in properties of modern synthetic fibers over the traditional clothing materials( and wool)has been quite shirts, dresses and suits made from polyesters liker Terylene and polyamides like Nylon are creaseresistant, machinewashable, and dripdry or are also cheaper than natural materials.（2） are all aware of the major contribution which the pharmaceutical sector of the industry has made to help keep us all healthy, curing bacterial infections with antibiotics, and even extending life itself, to lower blood pressure.(1) chemical industry makes a major contribution to food production in at leastthree , by making available large quantities of artificial fertilizers which are used to replace the elements(mainly nitrogen, phosphorus and potassium)which are removed by the growing crops during modern intensive ,by manufacturing protection chemicals , which markedly reduce the proportion of the crops consumed by ,by producing veterinary products which protect livestock from disease or cure their may seem strange in textbook like this one to pose the question ”do we need a chemical industry?” However, trying to answer this question will provide(i)an indication of the range of the chemical industry’s activates.(ii)Its influence on our lives in everyday terms, and(iii)how great is society’s need for a chemical approach in answering the question will be toconsider the industry’s contribution to meeting and satisfying our major are these? Clearly food(and drink)and health are which we shall consider in their turn are clothing and(briefly)shelter, leisure and Need for Chemical IndustryThe chemical industry is concerned with converting raw materials, such as crude oil, firstly into chemical intermediates, and then into a tremendous variety of other are then used to produce consumer products, which make our lives more fortable or，in some case such as pharmaceutical products,help to maintain our wellbeing or even life each stage of these operations value is added to the product and provided this added value exceeds the raw material plus processing costs then a profit will be made on the is the aim of chemical industry to achieve is therefore apparent that, because office diversity of operations and close links on many areas with other industries, there is no simple definition of the chemical each official body which collects and publishes statistics on manufacturing industry will have its definition as to which operations are classified as “the chemical industry.It is important to bear these in mind when paring statistical information which is derived from several 化學(xué)工業(yè)化學(xué)工業(yè)的定義上世紀(jì)初，定義化學(xué)工業(yè)的構(gòu)成是沒有什么困難的，因?yàn)橹挥蟹浅Ｓ邢薜漠a(chǎn)品被生產(chǎn)，而且這些產(chǎn)品是無害的化學(xué)制品如強(qiáng)堿和硫酸。然而現(xiàn)在大量的化學(xué)制品被生產(chǎn)，這些從未加工的材料如原油（在某些情況下）通過中間介質(zhì)得到可以直接消費(fèi)的產(chǎn)品，或某些準(zhǔn)備轉(zhuǎn)變?yōu)橄M(fèi)品。例如原油，首先要變成化工中間產(chǎn)品，然后轉(zhuǎn)變成相當(dāng)多種類的其他化工產(chǎn)品。其他的我們應(yīng)考慮它們換來的服飾，住房，娛樂及交通運(yùn)輸。現(xiàn)在的合成纖維的性能比以前的服飾材料（如麻，棉）有了顯著的改善。塑料和合成物在娛樂活動(dòng)引起一個(gè)相當(dāng)大的影響。典型的數(shù)字占到銷售收入的5％，是大部分研究和制藥部門的兩倍。計(jì)算機(jī)都得到了各種類型的廣泛應(yīng)用，從化工設(shè)備的自動(dòng)化控制到化合物的分子結(jié)構(gòu)模型，到實(shí)驗(yàn)室分析儀器的控制。p?ret]……蒸發(fā)；使……脫水；使……消失，揮發(fā)；消失，失蹤C(jī)ombustion [k?m39。In developing countries like Ghana where solid waste disposal is increasingly an environmental burden with its attendant health hazards, the idea of converting the organic fraction of municipal solid waste into energy for the national grid is a wele proposition towards reducing volumes of domestic waste to be disposed of or —；burden—；attendant—隨員、伴隨的；hazard—；convert—；organic fraction—有機(jī)部分；municipal—市政的；the national grid—國家電網(wǎng)；proposition—提議volumes of—大量的；在像加納這樣的發(fā)展中國家中，因?yàn)榘殡S著健康危害，固體垃圾處理正日益成為環(huán)境負(fù)擔(dān)，而把城市生活垃圾轉(zhuǎn)換成電能并輸送到國家電網(wǎng)中的想法，對于減少將被處理或填埋的大量的生活垃圾來說，是一個(gè)不錯(cuò)的提議。 higher temperatures are employed, toughness or shock resistance of the steel is increased, but the hardness and strength is the ability of a metal to change shape before it quenched martensite is hard but not ductile。Refine the grain structure of hot worked steels which may have developed coarse grain size。完全退火的突出的特點(diǎn)是：（a）溫度高于臨界溫度（b）緩慢冷卻，通常是爐冷。去應(yīng)力是指加熱鋼到轉(zhuǎn)變溫度以下的適宜溫度，正如回火一樣，但這樣做是為了減少內(nèi)應(yīng)力從而避免在加工過程中的變形和破裂。改變或修正鋼的磁性。另外，回火大大增加馬氏體抵抗沖擊負(fù)荷的能力。另一方面，退火過程的目的是為了使鋼更容易變形和機(jī)器加工。退火過程不必需要緩慢冷卻，因?yàn)樽畹娃D(zhuǎn)變溫度下的任何冷卻速度都會得到相同的微觀結(jié)構(gòu)和硬度。那就是說，一塊區(qū)域可能比周圍的含有更多的碳。當(dāng)一根鋼棒或鋼板被加熱到一個(gè)點(diǎn)高于另一個(gè)點(diǎn)，就像焊接或鍛造一樣，內(nèi)應(yīng)力就會產(chǎn)生。這步驟就叫做去應(yīng)力退火，或僅僅叫去應(yīng)力。ASME鍋爐和壓力標(biāo)準(zhǔn)中第八卷第一節(jié)指定一個(gè)范圍從15磅在底部到上限，然而，內(nèi)部壓