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
34
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.
【C20】
选项
A、incident
B、occasional
C、eventual
D、obvious
答案
A
解析
由空格前的meaning that可知后半句是对前半句的进一步解释,前面一直论述怎样利用各种材料吸收阳光并进行充分的转化。A项incident作形容词时含有“射入的”之义,incident light意为“射入的光线”。这些光线被吸收然后被半导体转为太阳能,符合语义逻辑。B项occasional“偶尔的”、C项eventual“最终的”和D项obvious“明显的”均不符合文章前面所述的“尽可能收集阳光”的情况。
转载请注明原文地址:https://kaotiyun.com/show/mZY4777K
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
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
在变化的市场环境中效率较高的组织结构是_______。
以合作为主、以互惠互利为基础的谈判应采用的让步方式是()
胆总管探查及引流术适用于
可能的癫痫发作类型是最佳选用的治疗药物为
不论宗地的类型如何,只要该类宗地有较发达的交易市场存在,可找到较多的交易实例,均适用()。
股份有限公司在财产清查时发现的存货盘亏、盘盈,应当于年末结账前处理完毕,如果确实尚未报经批准的,可先保留在“待处理财产损溢”科目中,待批准后再处理。()
下列各项中不符合契税计税依据的是()。
国家权力机关监督的客体包括()。
Whendoyouthinkthisconversationtookplace?
A、 B、 C、 C(A)Ms.Brooks是第三方,并不是正在对话的两个人之一,所以这一回答很别扭。(B)乍一听Ithink像是正确答案,但是抽屉里并不能成为宣布升职的场所。(C)在职工大会上宣布升职,这是正确答案。
最新回复
(
0
)