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
48
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.
【C17】
选项
A、Advanced
B、Special
C、Normal
D、Odd
答案
C
解析
由后半句的but可知本句是对新旧电池进行对比,因此所填入的词语应是和“新”相对的词,即普通的太阳能电池。故选C项Normal“通常的”。此处不是就电池做评价,因此A项Advanced“先进的”可排除。B项Special“特别的”与所表达意义相反。D项Odd“古怪的”不符合对普通电池的描述。
转载请注明原文地址:https://kaotiyun.com/show/N5MD777K
0
考研英语二
相关试题推荐
ZoeBuhlerwasscheduledforanultrasoundappointmentontheSeptembermorningwhenAustralianpoliceenteredherhome.Thepre
Everyonewantstobeauthentic.Youwanttobetruetoyourself,notaslavishfollowerofsocialexpectations.Youwantto"liv
AstudyinCyberpsychology,Behavior,andSocialNetworkingsuggeststhatartificialintelligenceholdsapromisingfutureinhe
AstudyinCyberpsychology,Behavior,andSocialNetworkingsuggeststhatartificialintelligenceholdsapromisingfutureinhe
AstudyofhowolderteenagersusesocialmediahasfoundthatFacebookis"notjustontheslide,itisbasicallydeadandburi
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
随机试题
关于女用避孕药的描述正确的是
职业健康安全管理体系的内部审核又称为()。
根据世界贸易组织有关协议,我国正式加入其在保险业上的承诺主要有()
某企业2018年年初拥有房产3栋,分别为:厂房1栋,原值500万元,已经使用5年,预计还可以使用20年;办公楼l栋(10层),原值1000万元,已经使用1年,预计还可以使用19年;仓库1栋,原值150万元,已经使用10年,预计还可以使用15年。2018年6
征收企业所得税时,下列项目中,应纳入企业收入总额的是()。
商品流通企业对是否要开拓新市场的决策,属于()决策。
下列关于每股收益的表述不正确的是()。
杭帮菜为浙菜的代表菜,烹饪上以()居多。
在(x2+3x+1)5的展开式中,x2系数为().
改造主观世界包括()
最新回复
(
0
)