We have found an IELTS reading simulation exercises--Time to cool it.
Dec 13th 2006
From The Economist print edition
1 REFRIGERATORS are the epitome of clunky technology: solid, reliable andjust a little bit dull. They have not changed much over the past century, butthen they have not needed to. They are based on a robust and effectiveidea--draw heat from the thing you want to cool by evaporating a liquid next toit, and then dump that heat by pumping the vapour elsewhere and condensing it.This method of pumping heat from one place to another served mankind well whenrefrigerators' main jobs were preserving food and, as air conditioners, coolingbuildings. 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 toreplace them.接下来为大家介绍"分折雅思阅读模拟练习：Time to cool it"
雅思阅读模拟练习：Time to cool it
2 One set of candidates are known as paraelectric materials. These act likebatteries when they undergo a temperature change: attach electrodes to them andthey generate a current. This effect is used in infra-red cameras. An array oftiny pieces of paraelectric material can sense the heat radiated by, forexample, a person, and the pattern of the array's electrical outputs can then beused to construct an image. But until recently no one had bothered much with theinverse of this process. That inverse exists, however. Apply an appropriatecurrent to a paraelectric material and it will cool down.
3 Someone who is looking at this inverse effect is Alex Mischenko, ofCambridge University. Using commercially available paraelectric film, he and hiscolleagues have generated temperature drops five times bigger than anypreviously recorded. That may be enough to change the phenomenon from alaboratory curiosity to something with commercial applications.
4 As to what those applications might be, Dr Mischenko is still a littlehazy. He has, nevertheless, set up a company to pursue them. He foresees puttinghis discovery to use in more efficient domestic fridges and air conditioners.The real money, though, may be in cooling computers.
5 Gadgets containing microprocessors have been getting hotter for a longtime. One consequence of Moore's Law, which describes the doubling of the numberof transistors on a chip every 18 months, is that the amount of heat produceddoubles as well. In fact, it more than doubles, because besides increasing innumber, the components are getting faster. Heat is released every time a logicaloperation is performed inside a microprocessor, so the faster the processor 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'scompany, Intel, in 1993, ran at 60m cycles a second. The Pentium 4--the last"single-core" desktop processor--clocked up 3.2 billion cycles a second.
6 Disposing of this heat is a big obstruction to further miniaturisationand higher speeds. The innards of a desktop computer commonly hit 80℃. At 85℃,they stop working. Tweaking the processor's heat sinks (copper or aluminiumboxes designed to radiate heat away) has reached its limit. So has tweaking thefans that circulate air over those heat sinks. And the idea of shifting fromsingle-core processors to systems that divided processing power between firsttwo, 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, thethermoelectric effect. Like paraelectric materials, this generates electricityfrom a heat source and produces cooling from an electrical source. Unlikeparaelectrics, a significant body of researchers is already working on it.
8 The trick to a good thermoelectric material is a crystal structure inwhich electrons can flow freely, but the path of phonons--heat-carryingvibrations that are larger than electrons--is constantly interrupted. Inpractice, this trick is hard to pull off, and thermoelectric materials are thusless efficient than paraelectric ones (or, at least, than those examined by DrMischenko). Nevertheless, Rama Venkatasubramanian, of Nextreme Thermal Solutionsin North Carolina, claims to have made thermoelectric refrigerators that can siton the back of computer chips and cool hotspots by 10℃. Ali Shakouri, of theUniversity of California, Santa Cruz, says his are even smaller--so small thatthey can go inside the chip.
9 The last word in computer cooling, though, may go to a system even lesstechy than a heat pump--a miniature version of a car radiator. Last year Applelaunched a personal computer that is cooled by liquid that is pumped throughlittle channels in the processor, and thence to a radiator, where it gives upits heat to the atmosphere. To improve on this, IBM's research laboratory inZurich is experimenting with tiny jets that stir the liquid up and thus makesure all of it eventually touches the outside of the channel--the part where theheat exchange takes place. In the future, therefore, a combination ofmicrochannels and either thermoelectrics or paraelectrics might cool computers.The old, as it were, hand in hand with the new.
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.
D. Alex Mischenko
E. Ali Shakouri
F. Rama Venkatasubramanian
1. ...and his research group use paraelectric film available from themarket to produce cooling.
2. ...sold microprocessors running at 60m cycles a second in 1993.
3. ...says that he has made refrigerators which can cool the hotspots ofcomputer chips by 10℃.
4. ...claims to have made a refrigerator small enough to be built into acomputer chip.
5. ...attempts to produce better cooling in personal computers by stirringup liquid with tiny jets to make sure maximum heat exchange.
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 areattached to them.
7. Dr. Mischenko has successfully applied his laboratory discovery tomanufacturing more efficient referigerators.
8. Doubling the frequency of logical operations inside a microprocessordoubles the heat output.
9. IBM will achieve better computer cooling by combining microchannels withparaelectrics.
Choose the appropriate letters A-D and write them in box 10 on your answersheet.
10. Which method of disposing heat in computers may have a brightprospect?
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.
Complete the notes below.
Choose one suitable word from the Reading Passage above for eachanswer.
Write your answers in boxes 11-14 on your answer sheet.
Traditional refrigerators use...11...pumps to drop temperature. At present,scientists are searching for other methods to produce refrigeration, especiallyin computer microprocessors....12...materials have been tried to generatetemperature drops five times bigger than any previously recorded. ...13...effecthas also been adopted by many researchers to cool hotspots in computers. Aminiature version of a car ...14... may also be a system to realize idealcomputer cooling in the future.
IELTS reading needs more practice.An article,Time to cool it, is not enough.We hope that the majority of candidates continue to work hard.
现在了解"艺术类专升硕留学项目分折雅思阅读模拟练习：Time to cool it"了吧？