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 nanotechnology. Yet over the past year also, a series
If you are a fan of science fiction, you’ve no doubt encountered the term nanotechnology. Yet over the past year also, a series
admin
2013-01-29
25
问题
If you are a fan of science fiction, you’ve no doubt encountered the term nanotechnology. 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 macromolecules 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://jikaoti.com/ti/k9qYFFFM
0
考博英语
相关试题推荐
FrictionbetweenAmerica’smilitaryanditscivilianoverseersisnothingnew.America’s220-yearexperimentinciviliancontrol
Everychildshouldestablishthe______idealtocontributetothemodernizationofourcountry.
Whatismeant【51】theword"friend"?Thedictionary【52】itas:."oneattachedto【53】byaffectionoresteem".Americansuset
Whatismeant【51】theword"friend"?Thedictionary【52】itas:."oneattachedto【53】byaffectionoresteem".Americansuset
Whatismeant【51】theword"friend"?Thedictionary【52】itas:."oneattachedto【53】byaffectionoresteem".Americansuset
Theserviceoperates36librariesthroughoutthecountry,whilesix______librariesspeciallyservethecountryside.
FreeAdviceIsJustAroundtheCorner(1)WhenDanielFranklin,apoliticalscienceprofessorfromAtlanta,neededcareeradv
MargheritaisaLondongirlandarrivingatCapitalwaslikecominghome."IgrewuplisteningtoCapitalRadio,"shesays."Peo
Atthefall2001SocialScienceHistoryAssociationconventioninChicago,theCrimeandJusticenetworksponsoredaforumonth
Atthefall2001SocialScienceHistoryAssociationconventioninChicago,theCrimeandJusticenetworksponsoredaforumonth
随机试题
客户机/服务器模式中,每个节点()
既是糖分解代谢的产物又是糖异生原料的物质是
禽类的卵黄囊憩室位于
急性颅内压增高时患者早期生命体征改变为
慢粒患者有哪条染色体改变
当人们在海洋游泳时,身体会释放一种看不见的电信号。科研人员根据这一情况研制了海洋隐形衣。该隐形衣通过屏蔽身体释放的电信号,使得鲨鱼等海洋生物无法发现人们的踪迹。这样,人们就可以近距离接触并观察鲨鱼等海洋生物。以下哪项是科研人员假设的前提?
甲因失恋,将前女友乙的照片传到网上,并公开她的姓名、电话、单位名称等,且捏造事实恶意中伤。乙要求网络服务提供者删除,但遭拒绝。对此,下列说法不正确的是()。
存款保证金
处理时不可分割的代码称为【71】。一旦这部分代码开始执行,则不允许任何中断打断。μC/OS–II系统调用宏【72】()执行关中断操作。
有三个关系R、S和T如下:由关系R和S通过运算得到关系T,则所使用的运算为
最新回复
(
0
)