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—conve
Sunlight is free, but that is no reason to waste it. Yet even the best silicon solar cells—by far the most【C1】________sort—conve
admin
2022-01-04
46
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.
【C4】
选项
A、as
B、to
C、for
D、with
答案
D
解析
空格处需要填入介词与replace搭配,用“什么代替什么”常用固定短语replace sth.with sth.来表达,故选D项with。A项replace sb./sth.as后接身份,表示“以……身份代替某人或某物”,不符合该句语义。B项to无此搭配。C项replace sb./sth.for后接替代某人/物的原因。
转载请注明原文地址:https://kaotiyun.com/show/CZY4777K
0
考研英语二
相关试题推荐
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Thosedaysarelonggonewhenplacingatelephonecallmeantsimplypickingupthereceiverandaskingtheoperatortopatchyou
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
随机试题
【背景资料】某公司承接了一项市政排水管道工程,管道为DN1200mm的混凝土管,合同价为1000万元,采用明挖开槽施工。项目部进场后立即编制施工组织设计,拟将表层杂填土放坡挖除后再打设钢板桩。设置两道水平钢支撑及型钢围檩,沟槽支护见图5-2。沟槽
12岁男孩,初生时正常,智力良好,家庭环境尚好,家长发现自幼生长慢于其他儿童,最近与同班同学相比差异更大。查体:身高110cm,体重20kg,心、肺、腹(一),双睾丸较同龄人小,声音细脆。预计这种异常最可能的疾病是
天时公司与地利公司合同纠纷一案,双方申请仲裁。仲裁过程中,双方达成和解协议。则:()
甲公司所得税税率为25%,税法规定,为第三方提供担保的损失不得税前扣除。A公司从乙银行取得贷款900万元,甲公司为其担保本息和罚息总额的70%,A公司逾期无力偿还借款,被乙银行起诉,甲公司成为第二被告,乙银行要求甲公司与被担保单位共同偿还贷款本息1050万
某出版社收到一部由某行业协会推荐的书稿。编辑小李审读全稿后,认为可以出版。他接下来要做的工作是()。
省民政厅需要在你市组织一个社区示范单位经验交流会,由你筹备会议,你准备做哪些工作?
如果将一台Catalyst6500交换机的管理地址设置为212.220.8.99/28,缺省路由设置为212.220.8.97,下列对交换机的配置,正确的是()。
HeatIsKillerExtremelyhotweatheriscommoninmanypartsoftheworld.Althoughhotweatherjustmakesmostpeoplefeel
Iftheseshoesaretoobig,buyasmaller______.
A、Ithasnowdevelopedintoamoderncity.B、Thefirstsettlerstherewereallfreedblackslaves.C、Itusedtobeabarrenspot
最新回复
(
0
)