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
90
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.
【C15】
选项
A、smashes
B、retains
C、drains
D、chops
答案
D
解析
Dr Rogers所研发的电池要克服传统电池不能有效利用光能的缺点,空格所在句提到“每一层……光谱的一部分,将其有效地转化为电能,并把剩下的光谱传递下去”。由此推出,电池的每一层要“截取”光谱的一部分,且填入的动词要能与off连用,所以D项chops“砍”为答案,chop off意为“砍掉”。A项smashes“粉碎”和C项drains“耗尽”均不符合“将其有效地转化”这一动作。B项retains“保持”为及物动词,其后直接接宾语,不接off。
转载请注明原文地址:https://kaotiyun.com/show/85MD777K
0
考研英语二
相关试题推荐
Everyonewantstobeauthentic.Youwanttobetruetoyourself,notaslavishfollowerofsocialexpectations.Youwantto"liv
AstudyinCyberpsychology,Behavior,andSocialNetworkingsuggeststhatartificialintelligenceholdsapromisingfutureinhe
TheWorldHealthOrganization(WHO)hasreleaseditsfirsteverguidanceonhowmuchtimeyoungchildrenshouldspendusingelec
AstudyofhowolderteenagersusesocialmediahasfoundthatFacebookis"notjustontheslide,itisbasicallydeadandburi
AstudyofhowolderteenagersusesocialmediahasfoundthatFacebookis"notjustontheslide,itisbasicallydeadandburi
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
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
随机试题
Theautoindustryspendslargeamountsofmoneyonmarketingcampaigns_________youngadultcustomers.
Airlinecompaniesareresponsiblefortransportingyourluggage.Ifyoucannotrecoveritatthepointofarrival,youmustinfo
阴部内动脉的分支有
患儿,男,3岁,哭闹时出现青紫1年。查体:心前区隆起,胸骨左缘第3~4肋间可闻及Ⅳ级收缩期杂音,可触及震颤。X线检查示:左右心室及左房增大,肺血管影增多,肺动脉段凸出。此患儿最可能的诊断是()
下面关于中国封建社会的刑法制度的说法不正确的是:()
在管理承包模式(MC)中,业主要求管理承包商提出保证最大工程费用。关于实际工程费用的说法,正确的是()。
签订()时,需要在专用条款中对其他合同文件的具体组成予以明确。
海关对企业在办理报关注册登记过程中所提交的文件、资料予以审核,在规定的期限内,按规定的职权范围进行审批,作出批准或不予批准的决定。我国海关现行规定()具有报关企业的审批权。
以下最早运用马克思主义观点阐述教育教学问题的著作是()
二元函数f(x,y)在点(x0,y0)处两个偏导数fx’(x0,y0),fy’(x0,y0)存在,是f(x,y)在该点连续的
最新回复
(
0
)