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
外语
If you are a fan of science fiction, you’ve no doubt encountered the term nanotechnol-ogy. Yet over the past year also, a series
If you are a fan of science fiction, you’ve no doubt encountered the term nanotechnol-ogy. Yet over the past year also, a series
admin
2017-03-25
23
问题
If you are a fan of science fiction, you’ve no doubt encountered the term nanotechnol-ogy. Yet over the past year also, a series of breakthroughs have transformed nanotech from sci-fi fantasy into a real world. Applied science, in the process, inspired huge investments by business, academia, and government. In industries as diverse as health care, computers, chemicals, and aerospace, nanotech is overhauling production techniques, resulting in new and improved products, some of which may already be in your home or workplace.
The inspiration for nanotech goes back to a 1959 speech by the late physicist Richard Feynman, then a professor at the California Institute of Technology, titled "There’s Plenty of Room at the Bottom. " Four decades later, Chad Mirkin, a Chemistry professor at Northwestern University’s $34 million nanotech center, used a nanoscale device to etch most of Feynman’s speech onto a surface the size of about 10 tobacco smoke particles.
What accounts for the sudden acceleration of nanotechnology? A key breakthrough came in 1990, when researchers at IBM’s Almaden Research Center succeeded in rearranging individual atoms at will. Using a device known as a scanning probe microscope, the team slowly moved 35 atoms to spell the three-letter IBM logo, thus proving Feynman right. The entire Logo was less than three nanometers.
Soon, scientists were not only manipulating individual atoms but "spray painting" with them as well. Using a tool known as a molecular beam epitaxy, scientists have learned to create ultra fine films of specialized crystals, built up one molecular layer at a time. This is the technology used today to build read-head components for computer hard drives.
The next stage in the development of nanotechnology borrows a page from nature. Building a supercomputer no bigger than a speck of dust might seem an impossible task, until one realizes that evolution solved such problems more than a billion years ago. Living cells contain all sorts of nanoscale motors made of proteins that perform myriad mechanical and chemical functions, from muscle contraction to photosynthesis. In some instances, such motors may be re-engineered, or imitated, to produce products and processes useful to humans.
How are these biologically inspired machines constructed? Often, they construct themselves, manifesting a phenomenon of nature known as self assembly. The macromole-cules of such biological machines have exactly the right shape and chemical binding preferences to ensure that when they combine they will snap together in predesigned ways. For example, the two strands that make up DNA’s double helix match each other exactly, which means that if they are separated in a complex chemical mixture, they are still able to find each other easily.
Scientists created ultra fine films of specialized crystals by means of______.
选项
A、a scanning probe microscope
B、a nanoscale device
C、a molecular beam epitaxy
D、a super computer
答案
C
解析
本题的四个选项中,只有C项为正确答案。这可从文中第四段的第二句话“Using a tool known as a molecular beam epitaxy…of specialized crystals…”推知,即科学家使用的是a molecular beam epitaxy来制造ultra fine films of specialized crystals。
转载请注明原文地址:https://kaotiyun.com/show/aZGO777K
0
考博英语
相关试题推荐
Inaperfectlyfreeandopenmarketeconomy,thetypeofemployer—governmentorprivate—schoolhavelittleornoimpactont
Theenergycontainedinrockwithintheearth’scrustrepresentsanearlyunlimitedenergysource,butuntilrecentlycommercial
TheFederalGovernment______farmersbybuyingtheirsurpluscropsatpricesabovethemarketvalue.
Assumingthataconstanttravel-timebudget,geographicconstraintsandshort-terminfrastructureconstraintspersistasfundame
Assumingthataconstanttravel-timebudget,geographicconstraintsandshort-terminfrastructureconstraintspersistasfundame
Don’tcallhimjustacollegeprofessor.Internetentrepreneur,TVpersonality,advisertopresidents,andfriendtotherichan
TheGreatWallisagreattourist______,drawingmillionsofvisitorsfromallpartsoftheworldeveryyear.
Newtechnologylinkstheworldasneverbefore.Ourplanethasshrunk.It’snowa"globalvillage"wherecountriesareonlyseco
Rentalhousing,whichisanimportantcomponentofpriceindices,lookslikelytomoderateinthenextyear,inpartbecauseof
____,hedidbecomeannoyedwithherattimes.
随机试题
ShirleyAllenlovedtosingandplaythepiano.Shestudiedmusicincollege.Herdreamwastobecomea【C1】______orsinger.
宫内节育器的避孕原理不包括
A.疖B.痈C.丹毒D.急性蜂窝织炎E.浅部急性淋巴管炎
2001年3月13日下午。陈某因曾揭发他人违法行为,被两名加害人报复砍伤。陈某逃跑过程中,两加害人仍不罢休,持刀追赶陈。途中,陈某多次拦车欲乘,均遭出租车司机拒载。当两加害人即将追上时,适逢一中年妇女丁某骑一摩托车(价值9000元)缓速行使。陈某当即哀求丁
涂刷防水涂料时,第二层涂刷的方向应与第一层()。
某教师在讲授《自己的事情自己干》一课时,设置了如下教学活动。一、自立的含义和表现这些和我们同龄甚至比我们还小的“候鸟学生”,远离父母,独自在外,他们自己提行李、坐火车,自己打水、梳头、洗衣服,独自面对生活和学习过程中的各种问题。你敢晒晒自己的自立经历
•LookatthestatementsbelowandatthefiveextractsfromanarticleaboutWebhostingprovider,itsresellerandoutsourcing.
Idon’tliketodisturbyou,becauseyou’requitetired()workinghardtoday.
A、It’stoohigh.B、It’sacceptable.C、It’scheapindeed.D、Thewomanshouldhavebargainedforit.C[听力原文]W:Ispent$50onthi
A、Therepairmanhadfinishedcleaningtheplugs.B、Therepairmanhadjuststartedworkingonhercar.C、Therepairmanhadlostt
最新回复
(
0
)