天童美语英语四级阅读模拟题及详解答案Word文件下载.docx

1、EsettleFcautiousGcooperateHgreatlyIdroppingJhardlyKintenseLfocusMaspirationNcriticalOprocedure参考答案：1.D2.I3.N4.G5.H6.F7.A8.C9.L10.BHeres the Totally Amazing Wonder Material That Could Revolutionize TechnologyA.In the technology industry,every new product or service seems to come with the promise that

2、 it is an innovation with the potential to change the world.Graphene（石墨烯），a form of carbon，might actually do just that.B.“Graphene is a wonderful material，”Jeanie Lau，a professor of physics at the University of California at Riverside，told Fortune.“It conducts heat 10 times better than copper and el

3、ectricity 100 times better than silicon，is transparent like plastic，extremely lightweight,extremely strong,yet flexible and elastic.In the past decade，it has taken the scientific and technology communities by storm，and has become the most promising electronic material to supplement or replace silico

4、n.”C.Graphene has already found its way into a number of compelling applications，Lau said.For instance，“since it is both transparent and electrically conductivetwo attributes rarely found in the same material in natureit has tremendous potential as the transparent electrode in monitors.displays;sola

5、r cells，and touch screens，”she explained.“Companies such as Samsung that invest heavily in this area have already secured patents，produced prototypes，and are expected to bring products to market in a few years.”Wearable electronic devices，aviation components，broadband photodetectors（光电检测器），radiation

6、-resistant coatings，sensors，and energy storage are among numerous other areas of active research.Lau said.D.For many researchers and investors，the ultimate application is graphene-based transistors，the building blocks of modem electronics.But getting there may take some time.A child of graphiteE.Fir

7、st produced in a lab back in 2004，graphene is essentially a single layer of pure carbon atoms bonded together in a honeycomb lattice so thin its actually considered two-dimensional.“We generally regard anything less than 10 layers of graphene as graphene;otherwise，its graphite，”said Aravind Vijayara

8、ghavan，a lecturer in nanomaterials at the University of Manchester.F.Even“graphene”is a bit of an umbrella term.“To oversimplify,there are two major types of graphene，”Michael Patterson，CEO of Graphene Frontiers，said.The first：“Nanoplatelets，”which are powders or flakes made from graphite.These have

9、 been around for a while and are“not really super-sexy,”Patterson said.“You mix them into polymers（聚合物）or inks or rubbers to make them conductive.”In flake form，graphene is already on its way to becoming a commodity,Patterson added.The other typein sheet or film formis where graphenes biggest promis

10、e lies.Graphene sheets have“incredible potential for electronics，”Patterson said.In the near term，that potential may manifest in situations where the quantity requirements are“not that great”and where quality or conductivity doesnt have to be as high，such as in basic touch-screen applications，he sai

11、d.Products that use graphene in this way could arrive to market in the next six to 1 2 months.G.Looking a little further out，graphene can be employed in membranes used for water desalination.Lockheed-Martin already has a patented product known as Perforene.“Its real and it works，but it wont be econo

12、mically viable until the product reaches an industrial scale where the cost is measured in pennies per square inch”rather than dollars or tens of dollars per square inch，Patterson explained.“Thats where were working today.”Its expensive and low-capacityH. But use of graphene in semiconductorsthe tec

13、hnologys Holy Grailis likely a decade away.“Many of the challenges presented by graphene are common to most new materials，”Paul Smith,a patent associate with the Intellectual Property Law Group at Fenwick & West，told Fortune.“The trick is figuring out how to synthesize graphene in a way that first i

14、s manufacturable beyond lab scale;second，preserves the desirable properties of the material;and third，can be integrated into a product or technology.”I.Synthesizing graphene in sheet form is considerably more expensive and time-consuming than producing graphene flakes.Whereas the latter typically in

15、volves a“quick and dirty”process by which bulk graphite is disassembled into millions of tiny pieces，Lau explained，large sheets of graphene are carefully“grown”on substrates（基板）such as copper，germanium，or silicon carbide.J. Graphene sheets are also prone to defects and“very difficult to make in good

16、 quality,”Ron Mertens，owner and editor of Graphene-Info.tom，said.Production capacity is also very limited.“There are thousands of small companies that can make graphene，but its expensive and low-capacity,”Mertens said.alround wafer measuring one inch in diameter,for instance，costs about$1 00，he adde

17、d.K.An even thornier obstacle on the way to graphene transistors is the fact that the material has no“band gap，”an essential property that allows transistors to be turned on and off without leaking electronic charge in the“off”state，said Elias Towe，a professor of electrical and computer engineering

18、at Carnegie Mellon University.L.“Band-gap engineering has been and remains the biggest challenge in the development of graphene transistors and computer chips.”Lau said.It requires controlling the material almost down at the atomic level，and“thats really pushing the edges of existing technology,”Pat

19、terson said.“In 10 years，we11 start to see these problems solved.”It is largely a matter of timeM.If graphene is to succeed as a replacement for silicon，every unit of cost and performance will make a difference，Towe said.N.“Silicon is hard to displace，with all the billions dollars of investments mad

20、e in manufacturing infrastructure，”he said.“A replacement for silicon has to offer extraordinary performance at extremely rock-bottom cost to compel industry to change its way.”O.Though graphene is just 10 years oldin contrast,use of silicon in transistors dates to the early 1950sconsiderable progre

21、ss has already been made.For example，the largest graphene sheet was produced by hand in a laboratory eight years ago;its width was less than that of a human hair.“Nowadays，roll-to-roll printing of graphene sheets up to 1 00 meters long has been achieved，”Lau said.“With the increasing interest，invest

22、ment，and research in graphene-based technology,I think it is largely a matter of time before the economy of scale kicks in and truly low-cost，large-scale production ofhigh-quality graphene is accomplished，”she added.46.Nanoplatelet is the powder-or flake-type of graphene that has been used for some

23、time to make conductors and that is being launched on the market.47.To encourage industry to replace silicon with graphene，it is necessary for graphene to provide high property at an extremely low expense.48.While graphene flakes are roughly processed with bulk graphite，graphene sheets are carefully

24、 made on substrates like copper，germanium，or silicon carbide.49.In the past ten years.graphene has become a hot topic among the scientific and technology groups.50.Perforene wont come into the market before it can be manufactured at a very low cost.51.Despite of a much younger age than silicon，great

25、 progress has been made in graphene;and with ever increasing interest，investment and research in graphene technology,its probable to manufacture cost- effective graphene of high quality.52.Graphene has been attempted to be used for plenty of noticeable applications.53.Yet it still needs to take ten

26、years for graphene to be used in semiconductors，which lies at the heart of the technology.54.With todays technology,it is still impossible to control material down at the atomic level.55.Elias Towe pointed out that having no“band gap”，the dispensable feature of transistors，makes it more difficult to produce graphene transistors.46.Nanoplatelet is the powder-or flake-type of graphene that has been used for some time to make conductors and that is being launched on the market.纳米片是粉末状或者薄片状的石墨烯，被用于制作导体已经有一段