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
This summer, as Olympic athletes go faster, higher, and stronger in London, a record has fallen in a lab in Hamburg: Scientists
This summer, as Olympic athletes go faster, higher, and stronger in London, a record has fallen in a lab in Hamburg: Scientists
admin
2015-03-25
61
问题
This summer, as Olympic athletes go faster, higher, and stronger in London, a record has fallen in a lab in Hamburg: Scientists have created the world’s lightest material. The new carbon nanomaterial, called Aerographite, weighs 0.2 milligrams per cubic centimeter. That’s less than a quarter the weight of the last record-holder, a nickel-phosphorous microlattice created by American researchers last year. And it’s six times lighter than air.
Nanotechnology researchers have been working with carbon nanotubes for years(as the name suggests, these are very, very small tubes made of carbon atoms), building everything from superlight bicycles to medical implants. What the German team(from the University of Hamburg and the University of Kiel)figured out was how to build a network of branching nanotu-bules, thereby making the material stronger and a better conductor of electricity—two qualities that make it much more widely useful in electronics. The unprecedented lightness was an unexpected bonus.
Aerographite was created by a clever molecular-scale version of the lost-wax process: Carbon gas was pumped into a furnace, where it coated a lattice of zinc oxide molecules(think of Dairy Queen hard-shell coating soft-serve ice cream). Then hydrogen gas was pumped into the furnace, bonding with the oxygen in the zinc oxide to form water, which evaporated, and leaving the zinc to in turn evaporate as gas. What was left was a hollow interconnected web of carbon tubes.
Aerographite has a foam-like consistency, so it’s hard to imagine building Formula One race cars or fighter jets out of it. Because of its extraordinary lightness and strength, though, as well as its compressibility(it can be squashed down by 95 percent without any damage)and ability to conduct electricity, its creators believe it can be used to create better batteries and other electrical components like supercapacitors. Using Aerographite would remove weight, of course, but, more important for power sources, could add energy—the anodes in batteries work by storing electrons, and all of the tiny pores in Aerographite are spaces for electrons to become embedded.
A cubic centimeter of Aerographite is 99.99 percent air, and perhaps the weirdest thing about it is that all that air actually makes the material heavier. Normally, things are light because they’re airy—as in Styrofoam or cotton candy. Not so with Aerographite, whose carbon nanotubes are actually less dense than the molecules in a cubic centimeter of air(six times less, as you’ll recall). The air in Aerographite weighs it own. Suck it out somehow, and the stuff would just lift off the table like a helium balloon.
About Aerographite, which of the following is TRUE?
选项
A、Air in this material is its own weight.
B、It is light because it’s airy.
C、It is as light as helium balloon.
D、Air makes it heavier than other materials.
答案
A
解析
推理判断题。根据选项提示词airy,helium balloon.定位至最后一段。该段最后两句指出:阿罗石墨中的空气就是其自身的重量。如果把空气抽干,这种物质就会像氦气球一样从桌面上升起来,由此可以推出[A]正确。
转载请注明原文地址:https://kaotiyun.com/show/iT74777K
0
考研英语一
相关试题推荐
Inthefollowingarticle,somesentenceshavebeenremoved.ForQuestions41-45,choosethemostsuitableonefromthelistA-G
Themostcriticaltimeinthelifeofahumanistheverybeginning—thefirsthoursafterbirth.Yetithasbeenonlywithinthe
ItisgenerallybelievedthatthedigitaldivideissomethingTheauthorseemstobelievethatwidenedwagegapcanbeattribut
EmployeesaredemandingmorefromtheiremployersbecauseTheword"gewgaws"(Paragraph6)mostprobablymeans
[A]Higherlivingstandard.[B]Importanceoftransportintrade.[C]Various,meansoftransport.[D]Birthoftransport-rela
AmericanScientistsTrytoDevelopArtificialBloodVesselwiththeSkinCellScientistshavegrownbloodvesselsforkidney
TheteachingofEnglishasasecondlanguage(ESL)inschoolshashadahistoryofconflictingarguments,interestinginnovation
Theinventionofbothlabor-savingtoolsandtoolsofintelligenceisrarelyaccidental.Instead,itisusuallytheproductofh
Parenthoodisn’tacareer-killer.Infact,economistswithtwoormorekidstendtoproducemoreresearch,notless,thantheir
Parenthoodisn’tacareer-killer.Infact,economistswithtwoormorekidstendtoproducemoreresearch,notless,thantheir
随机试题
20世纪90年代,俄罗斯联邦共和国颁布制定的法律主要有()
Asthedefiningepidemicofamodernagenotableforoverconsumptionandexcess,obesityishardtobeat.Theincreasedavailabi
某3×30m预应力连续梁桥,在其质量评定中,应划归为分部工程的包括()。
在经济活动实践中,如果当事人双方在签订合同时,价款或报酬不明确,合同履行中当事人应按()。
评估通用设备的重置成本,应首先考虑使用()。
()的含义是将未来的现金流按照一个固定的利率折现,使之等于当前的价格。
某房地产开发企业在土地使朋权挂牌出让中,以每平方米2100元的价格获得一块住宅用地,土地总面积20000平方米,容积率为3。经测算,预计开发建设总成本为每平方米建筑面积2500元(不含土地成本),销售税费率10%。在具体实施项目前,公司高层管理者提出要以市
A企业销售货物时,下列选项应当作为价外费用计算增值税销项税额的有()。
军队建设总目标的实现,是一个宏大的系统工程。江泽民依据邓小平新时期军队建设思想,结合不断发展的军队建设实际,从增强国防实力和履行军队根本职能出发,提出用政治合格、军事过硬、作风优良、()“五句话”来指导和规范我军的质量建设。
Youshouldspendabout20minutesonQuestions1-13whicharebasedonReadingPassage1below.PAPERRECYCLINGAPaperisdiffe
最新回复
(
0
)