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
考研
Sunlight is free, but that is no reason to waste it. Yet even the best silicon solar cells—by far the most【C1】________ sort—conv
Sunlight is free, but that is no reason to waste it. Yet even the best silicon solar cells—by far the most【C1】________ sort—conv
admin
2023-04-14
38
问题
Sunlight is free, but that is no reason to waste it. Yet even the best silicon solar cells—by far the most【C1】________ sort—convert only a quarter of the light that falls on them. Silicon has the【C2】________of being cheap: manufacturing improvements have brought its price to a point where it is snapping at the heels of fossil fuels.【C3】________many scientists would like to replace it【C4】________something fundamentally better.
John Rogers, of the University of Illinois, Urbana-Champaign, is one. The cells he has【C5】________can convert 42.5% of sunlight.【C6】________improved, Dr Rogers reckons, their efficiency could rise to 50%. Their【C7】________is that they are actually not one cell, but four, stacked one on top of another.
Solar cells are made of semiconductors, and every type of semiconductor has a【C8】________called a band gap that is different from that of other semiconductors. The band gap【C9】________the longest wavelength of light a semiconductor can absorb (it is transparent to longer wavelengths). It also fixes the【C10】________amount of energy that can be【C11】________ from shorter wavelength. The result is that long-wavelength photons are lost and short-wave ones incompletely utilised.
Dr Rogers【C12】________this by using a different material for each layer of the stack. He chooses his materials【C13】________ the bottom of the band gap of the top layer matches the top of the band gap of the one underneath, and so on【C14】________ the stack. Each layer thus【C15】________off part of the spectrum, converts it efficiently into electrical energy and passes the rest on.
The problem is that the materials needed to make these semiconductors are【C16】________. But Dr Rogers has found a way to overcome this.【C17】________solar-cell modules are completely covered by semiconductor, but in his only 0.1% of the surface is so covered. The semiconducting stacks, each half a millimeter square, are【C18】________over that surface many dots. Each stack then has a pair of cheap glass lenses【C19】________over it. These focus the sun’s light onto the stack, meaning that all【C20】________light meets a semiconductor.
【C2】
选项
A、merit
B、effect
C、accessory
D、bonus
答案
A
解析
根据空格后being cheap(便宜)可以判断这是硅的一种优势,故空格处应填入A项merit“优点”。由空格后的being cheap及冒号后的解释可知,本句讨论的是硅太阳能电池的价格,无关B项effect“效果”。此处讨论的是硅太阳能电池,而不是其部件,因此C项accessory“附件”也可排除。D项bonus“奖金,红利”与主题无关。
转载请注明原文地址:https://jikaoti.com/ti/4c1iFFFM
0
考研英语二
相关试题推荐
ZoeBuhlerwasscheduledforanultrasoundappointmentontheSeptembermorningwhenAustralianpoliceenteredherhome.Thepre
ZoeBuhlerwasscheduledforanultrasoundappointmentontheSeptembermorningwhenAustralianpoliceenteredherhome.Thepre
AstudyinCyberpsychology,Behavior,andSocialNetworkingsuggeststhatartificialintelligenceholdsapromisingfutureinhe
AstudyofhowolderteenagersusesocialmediahasfoundthatFacebookis"notjustontheslide,itisbasicallydeadandburi
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
随机试题
简述因特网的“综合传播媒体”功能。
在Excel2000工作表中,正确的Excel公式形式为_______。
关于减刑,下列哪一选项是正确的?
在下面列举的选项中,需要进行招标的项目是()。
不论委托合同是有偿或无偿的,处理委托事务的报酬不能代替支付处理委托事项的费用。()
累积影响分析应当从时间、空间两方面考虑,累积影响的具体形式为()。
税收的基本特征是指税收的强制性、()和固定性。
我国小学教师的劳动特点有哪些?
甲、乙、丙、丁四位同学在学校参加歌唱比赛的编号分别是1、2、3、4,四人恰好获得比赛的前四名,其中,三名同学发表了一些言论,甲说:“我不及丙的名次好。”得第三名的同学说:“甲不是第四名”。另一位同学说:“我们的编号和我们所得名次都不相同”。请问得第一名的是
Howmanycoursesdidthewomantakelastsemester?
最新回复
(
0
)