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
45
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://jikaoti.com/ti/Ac1iFFFM
0
考研英语二
相关试题推荐
ZoeBuhlerwasscheduledforanultrasoundappointmentontheSeptembermorningwhenAustralianpoliceenteredherhome.Thepre
TheWorldHealthOrganization(WHO)hasreleaseditsfirsteverguidanceonhowmuchtimeyoungchildrenshouldspendusingelec
Sunlightisfree,butthatisnoreasontowasteit.Yeteventhebestsiliconsolarcells—byfarthemost【C1】________sort—conv
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
Notsolongago,itwasthestuffofnightmares:youpickupthelandlinetelephoneandthere’snodialingtone.Nothing.Theph
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
下列关于异硫氰酸荧光素的叙述,正确的是
患者女,60岁。因不规则发热、腰痛、面部水肿5个月来诊。检测尿蛋白(+++),WBC5~10个/HP,尿本一周蛋白阳性;骨髓穿刺涂片可见骨髓瘤细胞0.20,此类细胞大,核仁明显,有双核及三核浆细胞。诊断为多发性骨髓瘤(MM)。患者的最佳治疗方案是
A.减少肠道氨的形成和吸收B.促进氨代谢C.减少假性神经递质的形成D.补充脑部正常神经递质E.防治脑水肿肝性脑病时,谷氨酸钠的作用机制是
绒毛膜癌最常见的转移部位是()
甲公司在与乙公司交易中获汇票一张,出票人为丙公司,承兑人为丁公司,付款人为戊公司,汇票到期日为2003年11月30日。当下列哪些情况发生时,甲公司可以在汇票到期日前行使追索权?
根据外商投资企业和外国企业所得税法律制度的规定,下列各项中,应计入应纳税所得额的有()。
某综合性企业2015年度发生如下业务:(1)与A公司签订一项易货合同,约定用120万元市场价格的库存商品换取市场价格为140万元的原材料,支付A公司差价20万元。(2)与B公司签订一份加工合同,为其加工一批特殊商品,原材料由该综合性企业提供,金
舌面前音,发音时舌面抬起与()构成阻碍。
已知(axy3一y2vosx)dx+(1+bysinx+3x2y2)dy为某一函数的全微分,则a,b取值分别为
LINDA:Lindawantsthecollegetoofferbetteradviceon【D1】______.Studentsneedmoreinformationaboutjobs【D2】______.Shethi
最新回复
(
0
)