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
65
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
Psychologistshaverecentlymountedanoffensiveagainstwhattheydescribeasnastinesstowardstudentsbyeducators.
Deathcomesquicklyinthemountains.Eachwinterholidaymakersarecaughtunawaresastheyhappilyskiawayfromthefixedrun
TherepressionintheNetherlands,insteadofsolvingacrucialproblem,elicitedbittercriticismfromeverymajorEuropeansta
Thedoctorsareverymuchworriedaboutthe______ofthepatient’sconditionafteroperation.
Boneandivoryarelight,strong,andaccessiblematerialsforInuitartists.
FamedsingerSteveWondercan’tseehisfansdancingathisconcerts.Hecan’tseethehandsofhisaudienceastheyapplaudwild
Asianeconomiccrisishasonlya______effectonthelivesofChinesepeople.
Mr.Mortongradually______aknowledgeofthesubject.
NewcomerstoSanFranciscowhocan’tspeakEnglishhaveahardtimefindinganapartment,ajob,orhealthcare.Institutionsth
Forfarmershopingforahealthyharvest,thebestplacetoturnforhelpthesedaysistheMonsantoCorp.Oneoftheworld’sle
随机试题
特种设备行政许可规定,特种设备在()时应到特种设备安全监督管理部门办理相关手续。
在下列几种商品中,商场会选择通过降价促销的方式来提高销售收入的是()。
甲:如果小张去,小李就去。乙:小张去了但小李没去。这两句话()。
美国国家航空航天局公布:“好奇”号确认火星上存在适合生命生存的物质,但目前仍然没有发现生命存在,其理由可能是()。
新时期最鲜明的特点是()。
对于颌面部损伤病员若不及时处理,会马上造成生命危险的主要原因是()。
甲和乙签订了一份买卖合同,约定甲先发货,乙再付款。甲在还没有发货时向乙请求支付货款,乙予以拒绝。乙所行使的权利是()
甲午战争以后,亡国灭种的威胁迫使中国人去寻找救亡之道,探求新的救国方案。资产阶级维新派掀起了一场维新救亡运动,维新运动有其特定的背景条件和思想基础。以下体现其背景条件和思想基础的是()
A、 B、 C、 D、 A
中国国家计算机网络设施是()
最新回复
(
0
)