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雅思阅读全真练习(2)

信息来源:网络  发布时间:2016-05-16

  本文为大家带来雅思阅读全真练习(2)的内容,希望大家能够关注。本系列的模拟试题在难度、长度、题材、题型方面都与雅思考试近似的练习。这些练习,均以国外报刊上的文章为素材,按雅思阅读的题型,出题并提供答案及简单注释。

  Time to cool it

  1 REFRIGERATORS are the epitome of clunkytechnology: solid, reliable and just a little bit dull.They have not changed much over the past century, but then they have not needed to. Theyare based on a robust and effective idea--draw heat from the thing you want to cool byevaporating a liquid next to it, and then dump that heat by pumping the vapour elsewhere andcondensing it. This method of pumping heat from one place to another served mankind wellwhen refrigerators' main jobs were preserving food and, as air conditioners, cooling buildings.Today's high-tech world, however, demands high-tech refrigeration. Heat pumps are no longerup to the job. The search is on for something to replace them.

  2 One set of candidates are known as paraelectric materials. These act like batteries whenthey undergo a temperature change: attach electrodes to them and they generate acurrent. This effect is used in infra-red cameras. An array of tiny pieces of paraelectric materialcan sense the heat radiated by, for example, a person, and the pattern of the array's electricaloutputs can then be used to construct an image. But until recently no one had bothered muchwith the inverse of this process. That inverse exists, however. Apply an appropriate currentto a paraelectric material and it will cool down.

  3 Someone who is looking at this inverse effect is Alex Mischenko, of Cambridge University.Using commercially available paraelectric film, he and his colleagues have generatedtemperature drops five times bigger than any previously recorded. That may be enough tochange the phenomenon from a laboratory curiosity to something with commercialapplications.

  4 As to what those applications might be, Dr Mischenko is still a little hazy. He has,nevertheless, set up a company to pursue them. He foresees putting his discovery to use inmore efficient domestic fridges and air conditioners. The real money, though, may be incooling computers.

  5 Gadgets containing microprocessors have been getting hotter for a long time. Oneconsequence of Moore's Law, which describes the doubling of the number of transistors on achip every 18 months, is that the amount of heat produced doubles as well. In fact, it morethan doubles, because besides increasing in number, the components are getting faster. Heat isreleased every time a logical operation is performed inside a microprocessor, so the faster theprocessor is, the more heat it generates. Doubling the frequency quadruples the heat output.And the frequency has doubled a lot. The first Pentium chips sold by Dr Moore's company,Intel, in 1993, ran at 60m cycles a second. The Pentium 4--the last "single-core" desktopprocessor--clocked up 3.2 billion cycles a second.

  6 Disposing of this heat is a big obstruction to further miniaturisation and higher speeds.The innards of a desktop computer commonly hit 80℃. At 85℃, they stop working. Tweakingthe processor's heat sinks (copper or aluminium boxes designed to radiate heat away) hasreached its limit. So has tweaking the fans that circulate air over those heat sinks. And theidea of shifting from single-core processors to systems that divided processing powerbetween first two, and then four, subunits, in order to spread the thermal load, also seems tohave the end of the road in sight.

  7 One way out of this may be a second curious physical phenomenon, the thermoelectriceffect. Like paraelectric materials, this generates electricity from a heat source and producescooling from an electrical source. Unlike paraelectrics, a significant body of researchers isalready working on it.

  8 The trick to a good thermoelectric material is a crystal structure in which electrons canflow freely, but the path of phonons--heat-carrying vibrations that are larger than electrons--isconstantly interrupted. In practice, this trick is hard to pull off, and thermoelectric materialsare thus less efficient than paraelectric ones (or, at least, than those examined by DrMischenko). Nevertheless, Rama Venkatasubramanian, of Nextreme Thermal Solutions in NorthCarolina, claims to have made thermoelectric refrigerators that can sit on the back of computerchips and cool hotspots by 10℃. Ali Shakouri, of the University of California, Santa Cruz, sayshis are even smaller--so small that they can go inside the chip.

  9 The last word in computer cooling, though, may go to a system even less techy than aheat pump--a miniature version of a car radiator. Last year Apple launched a personalcomputer that is cooled by liquid that is pumped through little channels in the processor, andthence to a radiator, where it gives up its heat to the atmosphere. To improve on this, IBM'sresearch laboratory in Zurich is experimenting with tiny jets that stir the liquid up and thusmake sure all of it eventually touches the outside of the channel--the part where the heatexchange takes place. In the future, therefore, a combination of microchannels and eitherthermoelectrics or paraelectrics might cool computers. The old, as it were, hand in hand with thenew.

  (830 words)

  Questions 1-5 Complete each of the following statements with the scientist or companyname from the box below.

  Write the appropriate letters A-F in boxes 1-5 on your answer sheet.

  A. Apple

  B. IBM

  C. Intel

  D. Alex Mischenko

  E. Ali Shakouri

  F. Rama Venkatasubramanian

  1. ...and his research group use paraelectric film available from the market to producecooling.

  2. ...sold microprocessors running at 60m cycles a second in 1993.

  3. ...says that he has made refrigerators which can cool the hotspots of computer chips by10℃.

  4. ...claims to have made a refrigerator small enough to be built into a computer chip.

  5. ...attempts to produce better cooling in personal computers by stirring up liquid withtiny jets to make sure maximum heat exchange.

  Questions 6-9 Do the following statements agree with the information given in the readingpassage?

  In boxes 6-9 on your answer sheet write

  TRUE if the statement is true according to the passage

  FALSE if the statement is false according to the passage

  NOT GIVEN if the information is not given in the passage

  6. Paraelectric materials can generate a current when electrodes are attached to them.

  7. Dr. Mischenko has successfully applied his laboratory discovery to manufacturing moreefficient referigerators.

  8. Doubling the frequency of logical operations inside a microprocessor doubles the heatoutput.

  9. IBM will achieve better computer cooling by combining microchannels with paraelectrics.

  Question 10 Choose the appropriate letters A-D and write them in box 10 on youranswer sheet.

  10. Which method of disposing heat in computers may have a bright prospect?

  A. Tweaking the processors?heat sinks.

  B. Tweaking the fans that circulate air over the processor抯 heat sinks.

  C. Shifting from single-core processors to systems of subunits.

  D. None of the above.

  Questions 11-14 Complete the notes below.

  Choose one suitable word from the Reading Passage above for each answer.

  Write your answers in boxes 11-14 on your answer sheet.

  Traditional refrigerators use...11...pumps to drop temperature. At present, scientists aresearching for other methods to produce refrigeration, especially in computermicroprocessors....12...materials have been tried to generate temperature drops five timesbigger than any previously recorded. ...13...effect has also been adopted by many researchersto cool hotspots in computers. A miniature version of a car ...14... may also be a system torealize ideal computer cooling in the future.

  答案及解析 Key and Explanations:

  1. D

  See Paragraph 3: ...Alex Mischenko, of Cambridge University. Using commercially available paraelectric film, he and his colleagues have generated temperature drops...

  2. C

  See Paragraph 5: The first Pentium chips sold by Dr Moore's company, Intel, in 1993, ran at 60m cycles a second.

  3. F

  See Paragraph 8: ...Rama Venkatasubramanian, of Nextreme Thermal Solutions in North Carolina, claims to have made thermoelectric refrigerators that can sit on the back of computer chips and cool hotspots by 10℃.

  4. E

  See Paragraph 8: Ali Shakouri, of the University of California, Santa Cruz, says his are even smaller梥o small that they can go inside the chip.

  5. B

  See Paragraph 9: To improve on this, IBM's research laboratory in Zurich is experimenting with tiny jets that stir the liquid up and thus make sure all of it eventually touches the outside of the channel--the part where the heat exchange takes place.

  6. TRUE

  See Paragraph 2: ...paraelectric materials. These act like batteries when they undergo a temperature change: attach electrodes to them and they generate a current.

  7. FALSE

  See Paragraph 3 (That may be enough to change the phenomenon from a laboratory curiosity to something with commercial applications. ) and Paragraph 4 (As to what those applications might be, Dr Mischenko is still a little hazy. He has, nevertheless, set up a company to pursue them. He foresees putting his discovery to use in more efficient domestic fridges?

  8. FALSE

  See Paragraph 5: Heat is released every time a logical operation is performed inside a microprocessor, so the faster the processor is, the more heat it generates. Doubling the frequency quadruples the heat output.

  9. NOT GIVEN

  See Paragraph 9: In the future, therefore, a combination of microchannels and either thermoelectrics or paraelectrics might cool computers.

  10. D

  See Paragraph 6: Tweaking the processor's heat sinks ?has reached its limit. So has tweaking the fans that circulate air over those heat sinks. And the idea of shifting from single-core processors to systems?also seems to have the end of the road in sight.

  11. heat

  See Paragraph 1: Today's high-tech world, however, demands high-tech refrigeration. Heat pumps are no longer up to the job. The search is on for something to replace them.

  12. paraelectric

  See Paragraph 3: Using commercially available paraelectric film, he and his colleagues have generated temperature drops five times bigger than any previously recorded.

  13. thermoelectric

  See Paragraph 7: ...the thermoelectric effect. Like paraelectric materials, this generates electricity from a heat source and produces cooling from an electrical source. Unlike paraelectrics, a significant body of researchers is already working on it.

  14. radiator

  See Paragraph 9: The last word in computer cooling, though, may go to a system even less techy than a heat pump--a miniature version of a car radiator.

  以上就是雅思阅读全真练习(2)的具体内容介绍,希望大家能够关注。相信本文内容,考生做起来还是有一定难度的,但是这是锲合雅思阅读试题的,考生必须多多练习。

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