2019年雅思阅读模拟试题:流程图题(1)
2019年雅思写作小作文流程图解析及范文:废纸回收

2019年雅思写作小作文流程图解析及范文:废纸回收The chart below shows the process of waste paper recycling.范文:The flow chart shows how waste paper is recycled. It is clear that there are six distinct stages in this process,from the initial collection of waste paper to the eventual production of usable paper.At the first stage in the paper recycling process, waste paper is collected either from paper banks, where members of the public leave their used paper, or directly from businesses. This paper is then sorted by hand and separated according to its grade, with any paper that is not suitablefor recycling being removed. Next, the graded paper is transported to a paper mill.Stages four and five of the process both involve cleaning. The paper is cleaned and pulped, and foreign objects such as staples are taken out. Following this, all remnants of inkand glue are removed from the paper at the de-inking stage. Finally, the pulp can be processed in a paper making machine, which makes the end product: usable paper.(160 words, band 9)。
2019年雅思阅读模拟试题:流程图题(2)

2019年雅思阅读模拟试题:流程图题(2) The Search for the Anti-aging PillIn government laboratories and elsewhere, scientists are seeking a drug able to prolong life and youthful vigor.Studies of caloric restriction are showing the wayAs researchers on aging noted recently, no treatment onthe market today has been proved to slow human aging - the build-up of molecular and cellular damage that increases vulnerability to infirmity as we grow older. But one intervention, consumption of a low-calorie*yet nutritionally balanced diet, works incredibly well in a broad range of animals, increasing longevity and prolonging good health. Those findings suggest that caloric restriction could delay aging and increase longevity in humans, too.Unfortunately, for maximum benefit, people would probably have to reduce their caloric intake by roughly thirty per cent, equivalent to dropping from 2,500 calories a day to1,750. Few mortals could stick to that harsh a regimen, especially for years on end. But what if someone could create a pill that mimicked the physiological effects of eating less without actually forcing people to eat less? Could such a'caloric-restriction mimetic', as we call it, enable peopleto stay healthy longer, postponing age-related disorders (such as diabetes, arteriosclerosis, heart disease and cancer) until very late in life? Scientists first posed this question in the mid-1990s, after researchers came upon a chemicalagent that in rodents seemed to reproduce many of caloric restriction's benefits. No compound that would safely achievethe same feat in people has been found yet, but the search has been informative and has fanned hope that caloric-restriction (CR) mimetics can indeed be developed eventually.The benefits of caloric restrictionThe hunt for CR mimetics grew out of a desire to better understand caloric restriction's many effects on the body. Scientists first recognized the value of the practice more than 60 years ago, when they found that rats fed a low-calorie diet lived longer on average than free-feeding rats and also had a reduced incidence of conditions that become increasingly common in old age. What is more, some of the treated animals survived longer than the oldest-living animals in the control group, which means that the maximum lifespan (the oldest attainable age), not merely the normal lifespan, increased. Various interventions, such asinfection-fighting drugs, can increase a population's average survival time, but only approaches that slow the body's rate of aging will increase the maximum lifespan.The rat findings have been replicated many times and extended to creatures ranging from yeast to fruit flies, worms, fish, spiders, mice and hamsters. Until fairly recently, the studies were limited to short-lived creatures genetically distant from humans. But caloric-restriction projects underway in two species more closely related to humans - rhesus and squirrel monkeys - have made scientists optimistic that CR mimetics could help people.calorie: a measure of the energy value of foodThe monkey projects demonstrate that, compared with control animals that eat normally, caloric-restricted monkeys have lower body temperatures and levels of the pancreatic hormone insulin, and they retain more youthful levels of certain hormones that tend to fall with age.The caloric-restricted animals also look better on indicators of risk for age-related diseases. For example, they have lower blood pressure and triglyceride levels (signifying a decreased likelihood of heart disease), and they have more normal blood glucose levels (pointing to a reduced risk for diabetes, which is marked by unusually high blood glucose levels). Further, it has recently been shown that rhesus monkeys kept on caloric-restricted diets for an extended time (nearly 15 years) have less chronic disease. They and the other monkeys must be followed still longer, however, to know whether low-calorie intake can increase both average and maximum life spans in monkeys. Unlike the multitude of elixirs being touted as the latest anti-aging cure, CR mimetics would alter fundamental processes that underlie aging. We aim to develop compounds that fool cells into activating maintenance and repair.How a prototype caloric-restriction mimetic worksThe best-studied candidate for a caloric-restriction mimetic, 2DG (2-deoxy-D-glucose), works by interfering with the way cells process glucose. It has proved toxic at some doses in animals and so cannot be used in humans. But it has demonstrated that chemicals can replicate the effects of caloric restriction; the trick is finding the right one.。
2019雅思阅读考试真题(11)

2019年雅思阅读模拟试题:流程图题(2) The Search for the Anti-aging PillIn government laboratories and elsewhere, scientists are seeking a drug able to prolong life and youthful vigor.Studies of caloric restriction are showing the wayAs researchers on aging noted recently, no treatment onthe market today has been proved to slow human aging - the build-up of molecular and cellular damage that increases vulnerability to infirmity as we grow older. But one intervention, consumption of a low-calorie*yet nutritionally balanced diet, works incredibly well in a broad range of animals, increasing longevity and prolonging good health. Those findings suggest that caloric restriction could delay aging and increase longevity in humans, too.Unfortunately, for maximum benefit, people would probably have to reduce their caloric intake by roughly thirty per cent, equivalent to dropping from 2,500 calories a day to1,750. Few mortals could stick to that harsh a regimen, especially for years on end. But what if someone could create a pill that mimicked the physiological effects of eating less without actually forcing people to eat less? Could such a'caloric-restriction mimetic', as we call it, enable peopleto stay healthy longer, postponing age-related disorders (such as diabetes, arteriosclerosis, heart disease and cancer) until very late in life? Scientists first posed this question in the mid-1990s, after researchers came upon a chemicalagent that in rodents seemed to reproduce many of caloric restriction's benefits. No compound that would safely achievethe same feat in people has been found yet, but the search has been informative and has fanned hope that caloric-restriction (CR) mimetics can indeed be developed eventually.The benefits of caloric restrictionThe hunt for CR mimetics grew out of a desire to better understand caloric restriction's many effects on the body. Scientists first recognized the value of the practice more than 60 years ago, when they found that rats fed a low-calorie diet lived longer on average than free-feeding rats and also had a reduced incidence of conditions that become increasingly common in old age. What is more, some of the treated animals survived longer than the oldest-living animals in the control group, which means that the maximum lifespan (the oldest attainable age), not merely the normal lifespan, increased. Various interventions, such asinfection-fighting drugs, can increase a population's average survival time, but only approaches that slow the body's rate of aging will increase the maximum lifespan.The rat findings have been replicated many times and extended to creatures ranging from yeast to fruit flies, worms, fish, spiders, mice and hamsters. Until fairly recently, the studies were limited to short-lived creatures genetically distant from humans. But caloric-restriction projects underway in two species more closely related to humans - rhesus and squirrel monkeys - have made scientists optimistic that CR mimetics could help people.calorie: a measure of the energy value of foodThe monkey projects demonstrate that, compared with control animals that eat normally, caloric-restricted monkeys have lower body temperatures and levels of the pancreatic hormone insulin, and they retain more youthful levels of certain hormones that tend to fall with age.The caloric-restricted animals also look better on indicators of risk for age-related diseases. For example, they have lower blood pressure and triglyceride levels (signifying a decreased likelihood of heart disease), and they have more normal blood glucose levels (pointing to a reduced risk for diabetes, which is marked by unusually high blood glucose levels). Further, it has recently been shown that rhesus monkeys kept on caloric-restricted diets for an extended time (nearly 15 years) have less chronic disease. They and the other monkeys must be followed still longer, however, to know whether low-calorie intake can increase both average and maximum life spans in monkeys. Unlike the multitude of elixirs being touted as the latest anti-aging cure, CR mimetics would alter fundamental processes that underlie aging. We aim to develop compounds that fool cells into activating maintenance and repair.How a prototype caloric-restriction mimetic worksThe best-studied candidate for a caloric-restriction mimetic, 2DG (2-deoxy-D-glucose), works by interfering with the way cells process glucose. It has proved toxic at some doses in animals and so cannot be used in humans. But it has demonstrated that chemicals can replicate the effects of caloric restriction; the trick is finding the right one.Cells use the glucose from food to generate ATP (adenosine triphosphate), the molecule that powers many activities in the body. By limiting food intake, caloric restriction minimizes the amount of glucose entering cells and decreases ATP generation. When 2DG is administered to animals that eat normally, glucose reaches cells in abundance but the drug prevents most of it from being processed and thus reduces ATP synthesis. Researchers have proposed several explanations for why interruption of glucose processing and ATP production might retard aging. One possibility relates to the ATP-making machinery's emission of free radicals, which are thought to contribute to aging and to such age-related diseases as cancer by damaging cells. Reduced operation of the machinery should limit their production and thereby constrain the damage. Another hypothesis suggests that decreased processing of glucose could indicate to cells that food is scarce (even if it isn't) and induce them to shift into an anti-aging mode that emphasizes preservation of the organism over such 'luxuries' as growth and reproduction.。
2019年雅思流程图9分范文及考官点评:砖块的制作-推荐word版 (2页)

2019年雅思流程图9分范文及考官点评:砖块的制作-推荐word版本文部分内容来自网络整理,本司不为其真实性负责,如有异议或侵权请及时联系,本司将立即删除!== 本文为word格式,下载后可方便编辑和修改! == 雅思流程图9分范文及考官点评:砖块的制作下面雅思为大家整理了雅思流程图9分范文及考官点评:砖块的制作,供考生们参考,以下是详细内容。
WRITING TASK 1You should spend about 20 minutes on this task .The diagram below shows the process by which bricks are manufactured for the building industry .Summarise the information by selecting and reporting the main features , and make comparisons where relevant .Write at least 150 words .Brick manufacturingClay : type of sticky earth that is used for making bricks , pots , etc .【满分范文】The process by which bricks are manufactured for the building industry can be outlined in seven consecutive steps . First the raw material , clay , which was just below the surface of soil in certain clay - rich areas has to be dug up by a digger .Then the lumps of clay are placed on a metal grid in order to break up the big chunks of clay into much smaller areas , which fall through the metal grid onto a roller , whose motion further segregates the bits of clay . Sand and water are added to make a homogenous mixture , which is then either formed in moulds or cutinto brick - shaped pieces by means of a wire cutter .Those fresh bricks are then kept in a drying oven for at least 24 and a maximum of 48 hours , several dozens if not hundreds of。
2019年雅思阅读模拟练习题1

This reading test contains 10 questions. You should spend about 20 minuteson this task.To make it more authentic, download the test and do it with pen and paper.Read the passage below and answer 10 questions.Early ClocksHumans have been trying, in various ways, to keep track of the passing oftime for around 6000 years. This means, of course, that for the very longstretch of human history before this time, people didn’t have ways to divide theday other than the rising and the setting of the sun. It is thought that theancient Sumerians may have been the first true time-keepers, but this is notclear as archaeological evidence is not sufficient. There is evidence, however,that the ancient Egyptians incorporated time-keeping as an aspect of their dailylife over five thousand years ago.The earliest type of clock, and the one which was used in ancient Egypt, was the sundial. As the name suggests, the sundial uses the sun to show thetime. There were many different types of such clocks in use at that time, but itis one type, the obelisk, which has become most closely linked with ancientEgypt. An obelisk is a tall, narrow stone tower, built outside, which would casta shadow on the ground in different places during different times of the day. Astime progressed, obelisks became more complex, and markings around the base ofthe tower could indicate further time divisions.Two centuries after obelisks were first used the Egyptians had expanded upon the idea and created more complex sundials. Sundials as we think of themtoday are flat stone objects with a long, narrow bar, called a gnomon, attachedat the centre of the ‘face’, or surface of the stone. The sun would shine downon the gnomon and its shadow would fall on the face, indicating the time ofday.Water clocks were among the first clocks which didn’t depend on the sun orstars to keep time. The oldest one known dates back to 1500 BC, and water clocksor ‘clepsydras’ became popular in amongst the Greeks and Arabs a thousand yearslater. The Clepsydra (Greek for “water thief”) consisted of a reservoir forholding water, and a mechanism by which water would and steadily flow or dripinto the reservoir. The rising level of the water would indicate how much timehad passed since the dripping began.The earliest water clocks were not very accurate, but as with the sundial,as time passed, water clocks became more mechanised and complex and they wereincreasingly outfitted with gadgets – some rang bells or gongs, some showed themovement of the planets, and some opened little windows to display statues orfigures. Just before the turn of the century, the Greeks built what is calledthe “tower of winds”, a complex water clock showing time, seasons, winddirection, and much more. Around this time, water clock making took root inChina, and after a thousand years of development, another famous clock, theeponymous Su Sung clock tower, was built. This tower clock was over 30 feet talland contained a variety of mechanisms not only for telling time accurately, butfor following the position of the stars and planets.The history of the development of clocks continued in Europe, and startinga few hundred years after the building of the Su Sung, clocks were developedthat kept time due to other natural phenomenon, mostly related to natural motion– the pulling of gravity, the swinging of pendulums, and finally, thereleasedtension of coiled springs, a mechanism which, for the first time, allowedportable watches to become a reality.QuestionsLabel the diagram below.Choose NO MORE THAN THREE WORDS from the passage for each answer.Classify the following features according to the type of clock:A) SundialsB) Water ClocksC) Other kinds of clocksWrite the correct letter, A, B or C in boxes 7-10 on your answer sheet.7) Developed in Europe after the Su Sung8) Served purposes other than telling time9) Were easily portable10) Oldest recorded time-keeping device参考答案Answers1) Obelisk2) Sundial3) Gnomon4) Face5) Water clock / Clepsydra6) Reservoir7) C8) B9) C10) A。
2019雅思阅读考试真题(4)

2019年雅思考试阅读模拟试题:段落标题(1)Volcanoes-earth-shattering newsWhen Mount Pinatubo suddenly erupted on 9 June 1991, the power of volcanoes past and present again hit the headlinesAVolcanoes are the ultimate earth-moving machinery. A violent eruption can blow the top few kilometres off a mountain, scatter fine ash practically all over the globe and hurl rock fragments into the stratosphere to darken the skies a continent away.But the classic eruption—cone-shaped mountain, big bang, mushroom cloud and surges of molten lava—is only a tiny part of a global story. Vulcanism, the name given to volcanic processes, really has shaped the world. Eruptions have rifted continents, raised mountain chains, constructed islands and shaped the topography of the earth. The entire ocean floorhas a basement of volcanic basalt.Volcanoes have not only made the continents, they arealso thought to have made the world's first stable atmosphere and provided all the water for the oceans, rivers and ice-caps. There are now about 600 active volcanoes. Every yearthey add two or three cubic kilometres of rock to the continents. Imagine a similar number of volcanoes smokingaway for the last 3,500 million years. That is enough rock to explain the continental crust.What comes out of volcanic craters is mostly gas. More than 90% of this gas is water vapour from the deep earth:enough to explain, over 3,500 million years, the water in the oceans. The rest of the gas is nitrogen, carbon dioxide, sulphur dioxide, methane, ammonia and hydrogen. The quantity of these gases, again multiplied over 3,500 million years, is enough to explain the mass of the world's atmosphere. We are alive because volcanoes provided the soil, air and water we need.BGeologists consider the earth as having a molten core, surrounded by a semi-molten mantle and a brittle, outer skin. It helps to think of a soft-boiled egg with a runny yolk, a firm but squishy white and a hard shell. If the shell is even slightly cracked during boiling, the white material bubbles out and sets like a tiny mountain chain over the crack—like an archipelago of volcanic islands such as the Hawaiian Islands. But the earth is so much bigger and the mantle below is so much hotter.Even though the mantle rocks are kept solid by overlying pressure, they can still slowly 'flow' like thick treacle. The flow, thought to be in the form of convection currents,is powerful enough to fracture the 'eggshell' of the crust into plates, and keep them bumping and grinding against each other, or even overlapping, at the rate of a few centimetres a year. These fracture zones, where the collisions occur, are where earthquakes happen. And, very often, volcanoes.CThese zones are lines of weakness, or hot spots. Every eruption is different, but put at its simplest, where there are weaknesses, rocks deep in the mantle, heated to 1,350℃, will start to expand and rise. As they do so, the pressure drops, and they expand and become liquid and rise more swiftly.Sometimes it is slow: vast bubbles of magma—molten rock from the mantle—inch towards the surface, cooling slowly, to show through as granite extrusions (as on Skye, or the Great Whin Sill, the lava dyke squeezed out like toothpaste that carries part of Hadrian's Wall in northern England). Sometimes—as in Northern Ireland, Wales and the Karoo in South Africa—the magma rose faster, and then flowed out horizontally on to the surface in vast thick sheets. In the Deccan plateau in western India, there are more than two million cubic kilometres of lava, some of it 2,400 metres thick, formed over 500,000 years of slurping eruption.Sometimes the magma moves very swiftly indeed. It does not have time to cool as it surges upwards. The gases trapped inside the boiling rock expand suddenly, the lava glows with heat, it begins to froth, and it explodes with tremendous force. Then the slightly cooler lava following it begins to flow over the lip of the crater. It happens on Mars, it happened on the moon, it even happens on some of the moons of Jupiter and Uranus. By studying the evidence, vulcanologists can read the force of the great blasts of the past. Is the pumice light and full of holes? The explosion was tremendous. Are the rocks heavy, with huge crystalline basalt shapes,like the Giant's Causeway in Northern Ireland? It was a slow, gentle eruption.The biggest eruptions are deep on the mid-ocean floor, where new lava is forcing the continents apart and widening the Atlantic by perhaps five centimetres a year. Look at maps of volcanoes, earthquakes and island chains like the Philippines and Japan, and you can see the rough outlines of what are called tectonic plates—the plates which make up the earth's crust and mantle. The most dramatic of these is the Pacific 'ring of fire' where there have been the most violent explosions—Mount Pinatubo near Manila, Mount St Helen's in the Rockies and El Chichón in Mexico about a decade ago, not to mention world-shaking blasts like Krakatoa in the Sunda Straits in 1883.DBut volcanoes are not very predictable. That is because geological time is not like human time. During quiet periods, volcanoes cap themselves with their own lava by forming a powerful cone from the molten rocks slopping over the rim of the crater; later the lava cools slowly into a huge, hard, stable plug which blocks any further eruption until the pressure below becomes irresistible. In the case of Mount Pinatubo, this took 600 years.Then, sometimes, with only a small warning, the mountain blows its top. It did this at Mont Pelée in Martinique at7.49 a.m. on 8 May, 1902. Of a town of 28,000, only two people survived. In 1815, a sudden blast removed the top1,280 metres of Mount Tambora in Indonesia. The eruption was so fierce that dust thrown into the stratosphere darkened the skies, cancelling the following summer in Europe and North America. Thousands starved as the harvests faded, after snowin June and frosts in August. Volcanoes are potentially world news, especially the quiet ones.。
雅思小作文-流程图

雅思小作文——流程图出现频率:低难易程度:高流程图和普通图表的区别在于:●流程图基本上不会出现数据,文字信息占主要地位●流程图以描述为主,比较的概率比较少●流程图需要把图中出现的信息都做描述,而普通图表则不需要将每一个数据都表述●流程图的时态比较单一,主要是用一般现在时●流程图的分段比较灵活,只要不同阶段之间的差距很明显,就可以另起一段●流程图可以不写总结段【如果写总结段,可以把步骤稍微总结一下】流程图注意事项:1)注意掌握段落连接或者不同阶段之间的说法(sequence expression)表示首阶段的一些说法:①The process starts from (名词or动名词)②At the first/initial stage + 句子③At the beginning of the cycle + 句子④During the initial phase + 句子⑤The beginning of the whole cycle is marked by (名词or动名词)⑥(名词or动名词)is the first step in (名词or动名词)表示次阶段的一些说法:①The second stage is(名词or动名词)②The next step in the process is (名词or动名词)表示最后阶段的一些说法:①(名词or动名词)is the last step in the procedure②The final phase of the procedure is about (名词or动名词)③In the final phase + 句子④Entering the final phase + 句子⑤(名词or动名词)is the final stage2)单词的转换主要体现在名词转换成动词。
流程图经常会出现一些器具的名词,如“grinder”“mixer”“heater”,考生需要改动成名词使用,如”ground”, “mixed”和”heated”例:The powders are delivered to the grinder, where they are ground into cement.3)注意流程图读图的顺序,很多是以循环形式出现4)除了连接词外,还可以使用分词结构和状语从句来表示顺序,如:下面几句话的意思是一样的,●Liquor butter is filtered, before being converted into solid butter.●Once liquor butter is filtered, it is converted into solid butter.●Liquor butter is filtered, until it is converted into solid matter.5)常用被动语态●误:Put these materials in the heater.●正:These materials are put in the heater.6)工序图的叙述流程图可以遵循下面的步骤:步骤1:确定材料步骤2:确定工具步骤3:确定动词,然后将这些信息写成一句话。
2019雅思阅读考试真题(7)

2019年雅思阅读模拟试题:流程图题(1) BAKELITEThe birth of modern plasticsIn 1907, Leo Hendrick Baekeland, a Belgian scientist working in New York, discovered and patented a revolutionary new synthetic material. His invention, which he named'Bakelite,’was of enormous technological importance, and effectively launched the modern plastics industry.The term 'plastic' comes from the Greek plassein, meaning 'to mould'. Some plastics are derived from natural sources, some are semi-synthetic (the result of chemical action on a natural substance), and some are entirely synthetic, that is, chemically engineered from the constituents of coal or oil. Some are 'thermoplastic', which means that, like candlewax, they melt when heated and can then be reshaped. Others are 'thermosetting': like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever. Bakelite had the distinction of being the first totally synthetic thermosetting plastic.The history of today's plastics begins with the discovery of a series of semi-synthetic thermoplastic materials in the mid-nineteenth century. The impetus behind the development of these early plastics was generated by a number of factors—immense technological progress in the domain of chemistry, coupled with wider cultural changes, and the pragmatic need to find acceptable substitutes for dwindling supplies of 'luxury' materials such astortoiseshell and ivory.Baekeland's interest in plastics began in 1885 when, asa young chemistry student inBelgium, he embarked on research into phenolic resins, the group of sticky substances produced when phenol (carbolic acid) combines with an aldehyde (a volatile fluid similar to alcohol). He soon abandoned the subject, however, only returning to it some years later. By 1905 he was a wealthy New Yorker, having recently made his fortune with the invention of a new photographic paper. While Baekeland had been busily amassing dollars, some advances had been made in the development of plastics. The years 1899 and 1900 had seen the patenting of the first semi-synthetic thermosetting material that could be manufactured on an industrial scale. In purely scientific terms, Baekeland's major contribution to the field is not so much the actual discovery of the material to which he gave his name, butrather the method by which a reaction between phenol and formaldehyde could be controlled, thus making possible its preparation on a commercial basis. On 13 July 1907, Baekeland took out his famous patent describing this preparation, the essential features of which are still in use today.The original patent outlined a three-stage process, in which phenol and formaldehyde (from wood or coal) wereinitially combined under vacuum inside a large egg-shaped kettle. The result was a resin known as Novalak which became soluble and malleable when heated. The resin was allowed to cool in shallow trays until it hardened, and then broken up and ground into powder. Other substances were then introduced:including fillers, such as woodflour, asbestos or cotton, which increase strength and moisture resistance, catalysts substances to speed up the reaction between two chemicalswithout joining to either) and hexa, a compound of ammoniaand formaldehyde which supplied the additional formaldehyde necessary to form a thermosetting resin. This resin was then left to cool and harden, and ground up a second time. The resulting granular powder was raw Bakelite, ready to be made into a vast range of manufactured objects. In the last stage, the heated Bakelite was poured into a hollow mould of the required shape and subjected to extreme heat and pressure, thereby 'setting' its form for life.The design of Bakelite objects, everything from earrings to television sets, was governed to a large extent by the technical requirements of the molding process. The objectcould not be designed so that it was locked into the mouldand therefore difficult to extract. A common general rule was that objects should taper towards the deepest part of the mould, and if necessary the product was molded in separate pieces. Moulds had to be carefully designed so that themolten Bakelite would flow evenly and completely into the mould. Sharp corners proved impractical and were thus avoided, giving rise to the smooth, streamlined' style popular in the 1930s. The thickness of the walls of the mould was also crucial: thick walls took longer to cool and harden, .afactor which had to be considered by the designer in order to make the most efficient use of machines.Baekeland's invention, although treated with disdain inits early years, went on to enjoy an unparalleled popularity which lasted throughout the first half of the twentieth century. It became the wonder product of the new world of industrials expansion—‘the material of a thousand uses’. Being both non-porous and heat-resistant, Bakelite kitchengoods were promoted as being germ-free and sterilisable. Electrical manufacturers seized on its insulating properties, and consumers everywhere relished its dazzling array of shades, delighted that they were now, at last, no longer restricted to the wood tones and drab browns of thepreplastic era. It then fell from favour again during the 1950s, and was despise and destroyed in vast quantities. Recently, however, it has been experiencing something of a renaissance, with renewed demand for original Bakelite objects in the collectors' marketplace, and museums,societies and dedicated individuals once again appreciating the style and originality of this innovative material.。
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2019年雅思阅读模拟试题:流程图题(1) BAKELITEThe birth of modern plasticsIn 1907, Leo Hendrick Baekeland, a Belgian scientist working in New York, discovered and patented a revolutionary new synthetic material. His invention, which he named'Bakelite,’was of enormous technological importance, and effectively launched the modern plastics industry.The term 'plastic' comes from the Greek plassein, meaning 'to mould'. Some plastics are derived from natural sources, some are semi-synthetic (the result of chemical action on a natural substance), and some are entirely synthetic, that is, chemically engineered from the constituents of coal or oil. Some are 'thermoplastic', which means that, like candlewax, they melt when heated and can then be reshaped. Others are 'thermosetting': like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever. Bakelite had the distinction of being the first totally synthetic thermosetting plastic.The history of today's plastics begins with the discovery of a series of semi-synthetic thermoplastic materials in the mid-nineteenth century. The impetus behind the development of these early plastics was generated by a number of factors—immense technological progress in the domain of chemistry, coupled with wider cultural changes, and the pragmatic need to find acceptable substitutes for dwindling supplies of 'luxury' materials such astortoiseshell and ivory.Baekeland's interest in plastics began in 1885 when, asa young chemistry student inBelgium, he embarked on research into phenolic resins, the group of sticky substances produced when phenol (carbolic acid) combines with an aldehyde (a volatile fluid similar to alcohol). He soon abandoned the subject, however, only returning to it some years later. By 1905 he was a wealthy New Yorker, having recently made his fortune with the invention of a new photographic paper. While Baekeland had been busily amassing dollars, some advances had been made in the development of plastics. The years 1899 and 1900 had seen the patenting of the first semi-synthetic thermosetting material that could be manufactured on an industrial scale. In purely scientific terms, Baekeland's major contribution to the field is not so much the actual discovery of the material to which he gave his name, butrather the method by which a reaction between phenol and formaldehyde could be controlled, thus making possible its preparation on a commercial basis. On 13 July 1907, Baekeland took out his famous patent describing this preparation, the essential features of which are still in use today.The original patent outlined a three-stage process, in which phenol and formaldehyde (from wood or coal) wereinitially combined under vacuum inside a large egg-shaped kettle. The result was a resin known as Novalak which became soluble and malleable when heated. The resin was allowed to cool in shallow trays until it hardened, and then broken up and ground into powder. Other substances were then introduced:including fillers, such as woodflour, asbestos or cotton, which increase strength and moisture resistance, catalysts substances to speed up the reaction between two chemicalswithout joining to either) and hexa, a compound of ammoniaand formaldehyde which supplied the additional formaldehyde necessary to form a thermosetting resin. This resin was then left to cool and harden, and ground up a second time. The resulting granular powder was raw Bakelite, ready to be made into a vast range of manufactured objects. In the last stage, the heated Bakelite was poured into a hollow mould of the required shape and subjected to extreme heat and pressure, thereby 'setting' its form for life.The design of Bakelite objects, everything from earrings to television sets, was governed to a large extent by the technical requirements of the molding process. The objectcould not be designed so that it was locked into the mouldand therefore difficult to extract. A common general rule was that objects should taper towards the deepest part of the mould, and if necessary the product was molded in separate pieces. Moulds had to be carefully designed so that themolten Bakelite would flow evenly and completely into the mould. Sharp corners proved impractical and were thus avoided, giving rise to the smooth, streamlined' style popular in the 1930s. The thickness of the walls of the mould was also crucial: thick walls took longer to cool and harden, .afactor which had to be considered by the designer in order to make the most efficient use of machines.Baekeland's invention, although treated with disdain inits early years, went on to enjoy an unparalleled popularity which lasted throughout the first half of the twentieth century. It became the wonder product of the new world of industrials expansion—‘the material of a thousand uses’. Being both non-porous and heat-resistant, Bakelite kitchen。