首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
To get from Kathmandu to the tiny village in Nepal, Dave Irvine-Halliday spent more than two days. When he arrived, he found vil
To get from Kathmandu to the tiny village in Nepal, Dave Irvine-Halliday spent more than two days. When he arrived, he found vil
admin
2012-07-18
85
问题
To get from Kathmandu to the tiny village in Nepal, Dave Irvine-Halliday spent more than two days. When he arrived, he found villagers working and reading around battery-powered lamps equipped with light-emitting diodes, or LEDs—the same lamps he had left there in 2000.
Irvine-Halliday, an American photonics engineer, was not surprised. He chose to use LED bulbs because they are rugged, portable, long-lived, and extremely efficient. Each of his lamps produces a useful amount of illumination from just one watt of power. Villagers use them about four hours each night, then top off the battery by pedaling a generator for half an hour. The cool, steady beam is a huge improvement over lamps still common in developing Countries. In fact, LEDs have big advantages over familiar incandescent (白炽的)lights as well—so much so that Irvine-Halliday expects LEDs will eventually take over from Thomas Edison’s old lightbulb as the world’s main source of artificial illumination.
The dawn of LEDs began about 40 years ago, but early LEDs produced red or green glows suitable mainly for displays in digital clocks and calculators. A decade ago, engineers invented a semiconductor crystal made of an aluminum compound that produced a much brighter red light. Around the same time, a Japanese engineer developed the first practical blue LED. This small advance had a huge impact because blue, green, and red LEDs can be combined to create most of the colors of the rainbow, just as that in a color television picture.
These days, high-intensity color LEDs are showing up everywhere such as the traffic lights. The reasons for the rapid switchover are simple. Incandescent bulbs have to be replaced annually, but LED traffic lights should last five to yen years. LEDs also use 80 to 90 percent less electricity than the conventional signals they replace. Collectively, the new traffic lights save at least 400 million kilowatt-hours a year in the United States.
Much bigger savings await if LEDs can supplant Mr. Edison’s bulb at the office and in the living room. Creating a white-light LED that is energy-saving, cheap and appealing has proved a tough engineering challenge. But all the major lightbulb makers—including General Electric, Philips, and Osram-Sylvania—are teaming up with semiconductor manufacturers to make it happen.
Which of the following statements does not agree with the facts in the passage?
选项
A、The displays in digital clocks and calculators are just produced by early LEDs.
B、Irvine-Halliday believes that LED will certainly become the world’s main source of artificial light.
C、A decade ago, engineers developed red and blue LEDs, which were regarded as a milestone in this research.
D、It is the blue LED developed by a Japanese engineer that had a great impact on the research process.
答案
C
解析
这是一道事实寻读题。第三段说,10年前一位日本工程师研制出了蓝色发光二极管,这个小小的进展具有极大的影响,因为红、绿、蓝是组成彩虹的主要颜色。
转载请注明原文地址:https://kaotiyun.com/show/gKnO777K
0
考博英语
相关试题推荐
Althoughofcoursethereareexceptions,itseemsreasonablyclearthatincertaincountries—Rwanda,Somaliaandpartsofthefo
Citiesdevelopasaresultoffunctionsthattheycanperform.Somefunctionsresultdirectlyfromtheingenuityofthecitizenr
Agreathornedowlhootsacrossthequietwater-andthenglidesthroughthestandofbaldcypressalongtheeasternsideofthe
Dublinwillnolonger______itsconstitutionalclaimtoNorthernIreland,asithadpromisedtodoonSunday.
IhaveobservedthattheAmericansshowalessdecidedtasteforgeneralideasthantheFrench.Thisisespeciallytrueinpolit
Itisuptothegovernmenttotackletheairpollutionproblemand______measuresinlinewiththecouncil’ssuggestions.
Don’tmeddleinmyaffairs,andinfactaIcanhandlethemproperlybymyself.
Charmistheultimateweapon,thesupremeseduction,againstwhichtherearefewdefenses.Ifyou’vegotit,youneedalmostnot
Whoeversaidthatvictoryhasmanyfathersanddefeatisanorphan,surelyhadneverheardoftheWorldTradeorganization(WTO)
Hecannot______thefactthathewaslateagainfortheconferenceattheuniversityyesterday.
随机试题
在整个环境标准中处于核心地位的是()
顺逆两境又常相间以迭乘。以:迭乘:
甲和乙是一对关系很好的朋友,一次因为一件小事发生争执,甲一气之下用砖头打破了乙的头。在民法上,甲的行为侵犯了乙的()
女性,51岁,孕3产3,阴道不规则流血3个月,量时多时少。既往月经规律,3~4天/28~30天,放置宫内节育器(惰性不锈钢环)20年。临床上首选的治疗方法是
关于手术后疼痛对机体的影响,不正确的是
A.处拘役或者管制B.处3年以下有期徒刑C.处7年以上有期徒刑,并处罚金D.处15年有期徒刑或无期徒刑根据《中华人民共和国刑法》某个体诊所无《医疗机构制剂许可证》,擅自用中药黄芪、黄连等生产胃康冲剂,虽未发现对人体造成严重危害,销售金额
2014年,为迎接APEC会议的召开,北京、天津、河北等地实施“APEC治理模式”,采取了有史以来最严格的减排措施。果然,令人心醉的“APEC蓝”出现了。然而,随着会议的结束,“APEC蓝”也渐渐消失了。对此,有些人士表示困惑,既然政府能在短期内实施“AP
有些情况下如多线程对共享数据操作时,这种线程运行顺序的不确定性将会产生执行结果的不确定性,使共享数据的一致性被破坏,因此,在某些应用程序中必须对线程进行______.
Islanguage,likefood,abasichumanneedwithoutwhichachildatacriticalperiodoflifecanbestarvedanddamaged?Judgin
____________(虽然只懂得一点语法),heattendthecourse.
最新回复
(
0
)