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
29
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.
【C18】
选项
A、accumulated
B、assembled
C、scattered
D、decorated
答案
C
解析
本句提到新电池的半导体面积仅为0.5平方毫米,其体积极小,不可能占据电池堆很多地方,因此只能是散布在其上,故C项scattered“散布”为答案。A项accumulated “积累”表示数量由少至多,空格所在句无此意。B项assembled“集合”,主语一般为“人”,故不符合本句的主语“许多点”。半导体的功能不是用来装饰的,因此D项decorated亦可排除。
转载请注明原文地址:https://kaotiyun.com/show/QZY4777K
0
考研英语二
相关试题推荐
Whichofthefollowingcanbethebesttitleofthispassage?Thereasonwhythebraincellsofthepersonwhobothsmokesand
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Thosedaysarelonggonewhenplacingatelephonecallmeantsimplypickingupthereceiverandaskingtheoperatortopatchyou
Thosedaysarelonggonewhenplacingatelephonecallmeantsimplypickingupthereceiverandaskingtheoperatortopatchyou
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
造成离合器打滑的原因有哪些?
计算机病毒具有()、潜伏性和爆发性等特点。
It’scommonknowledgethattoday’sworkplaceismorevolatile(易变的)thanitoncewas.Onehastoknowhowtomakethenecessa
麻疹病毒的特征是
异地临时经营活动可在异地开立临时存款账户。()
OECD于2015年10月发布税基侵蚀和利润转移项目全部15项产出成果。下列各项中,属于该产出成果的有()。
品牌联想是基于()的心理联想,它反映了品牌在消费者心目中的稳定性。
下列条目中,哪些是当SQL语句嵌入到主语言时要解决的问题Ⅰ.区分SQL语句与主语言语句Ⅱ.数据库工作单元和程序工作单元之间的通信Ⅲ.协调SQL语句与主语言语句处理记录的不同方式
WhatdidKarlaDeCaprioenjoymostasahumanresourceprofessional?
Theicecreamconeandtheicedteawereallintroducedatthe1904LouisianaPurchaseExposition,accidentallygiventhenameo
最新回复
(
0
)