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
33
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.
The author implies that villagers liked LED bulbs very much, because they_____.
选项
A、were given by Irvine-Halliday
B、are rugged
C、are cheap
D、are easily-recharged
答案
D
解析
这是一道引申判断题。第二段提到,村民们每晚用电4个小时,然后用脚踏的方式来给电池充电。可以想象,在一个遥远的小村庄,这可能是最理想的充电方式了。
转载请注明原文地址:https://kaotiyun.com/show/0KnO777K
0
考博英语
相关试题推荐
Havingliberatedtheplayerfromanexclusivelyteamperformance,LouisArmstrongunwittinglycodifiedthevocabularyofthesol
Therehasbeenanincreaseinattendanceatlectures______bytheWorldAffairsCouncil,whichbringsinternationalissuestop
Thecaronedrivesmayshowhis/her______orsocialposition.
Thedoctorponderedforawhile,tryingtorecallwhichofseveralmedicationswouldbebestto______thepatient’ssuffering.
TheMinister’s______answerledtoanoutcryfromtheOpposition.
TheCommitteepronouncedfourmembersexpelledforfailuretoprovideinformationinthe______ofinvestigations.
Agreathornedowlhootsacrossthequietwater-andthenglidesthroughthestandofbaldcypressalongtheeasternsideofthe
Dublinwillnolonger______itsconstitutionalclaimtoNorthernIreland,asithadpromisedtodoonSunday.
Youareexposedtoobtrusiveadsthat______seeminglyfromnowhereevenwhenyouaredisconnectedfromtheNet,andyourperson
Sofarasthefoodindustryisconcerned,theprocessingofsheepandlambsisrelatively______intheUnitedStates,accountin
随机试题
在主体的审美心理结构中必然处于最高位置的是()
Meetingboysissometimeseasy,sometimesdifficult,butineithercase,itisonlythebeginning.Manygirlstryalltheapproa
女性,40岁,既往体健,不明原因出现左面部麻木和眼球活动障碍25天。检查发现左面部感觉缺失,复视,水平运动仅左眼可外展;四肢腱反射消失,行走不稳。2个月前有双侧面神经麻痹史。首先应该考虑何种疾病
天然骨料开采,在河漫滩多采用()。
甲公司于1月5日向乙企业发出签订合同的要约信函。1月8日,乙企业收到甲公司声明该要约作废的传真。1月10日,乙公司收到该要约的信函。根据合同法律制度的规定,甲公司发出传真声明要约作废的行为属于()。
法国A公司是国际知名的电气跨国公司,十年前通过设立中国分公司进入中国市场。针对中国成为世界加工厂和世界经济的有力推动者之一的趋势不断加强,A公司开始着手研究在中国的发展战略。经过十年充分的战略情报研究和战略保障准备,从2005年开始在中国实施并购。
OneSundaymorning,MillieandAmywenttoSunshinePark.Theylovetochatthere.Asusual,theysat【C1】______abigtree.Sudde
我国政府公职人员的奖励有以下几种类型()。
8,4,4,6,15,()
中国特色社会主义理论体系在党的()提出,是包括()等重大战略思想在内的科学理论体系。
最新回复
(
0
)