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
While chemists try to assemble molecules using a combination of theoretical principles and practical experience to mold m
While chemists try to assemble molecules using a combination of theoretical principles and practical experience to mold m
admin
2011-01-17
90
问题
While chemists try to assemble molecules using a combination of theoretical
principles and practical experience to mold molecules that have desired
structural and chemical properties, nanotechonologists generally seek to make
Line more than a single molecule. They build arrays of identical or complexed
(5) molecules, sometimes on a scale that will transcend the boundaries of the
microscopic and approach the macroscopic, using both top-down and bottom-up
approaches. The first is exemplified by scientists who build objects and
molecular arrays using the techniques of scanning probe microscopy, while the
second is exemplified by investigators who design two-and three-dimensional
(10) chemical systems that cohere according to the rules of chemical interactions.
The top-down approach has exquisite precision, but its disadvantage is its lack
of extensive parallelism; it requires manipulating atoms and molecules
practically one by one, while the bottom-up approach is massively parallel. But
in both cases, scientists are forced to use the difficult nanometer scale, i.e. the
(15) level at which living systems tend to make their structural components, rather
than the angstrom scale of chemistry.
It can be inferred from the passage that the author believes which of the following concerning the top-down method of nanotechnology?
选项
A、The top-down method tends to be accurate but highly inefficient, resulting in a process that takes a great deal of time and energy.
B、The top-down method, unlike the bottom-up method, tends to disobey the rules of many chemical interactions.
C、The top-down method requires a greater level of technological involvement than does the bottom-up method.
D、The top-down method shows the limits of nanotechnology methods that rely too heavily on parallel processes.
E、The top-down method is fairly useless when applied to the problem of creating a single molecule.
答案
A
解析
转载请注明原文地址:https://www.kaotiyun.com/show/2hjO777K
本试题收录于:
GRE VERBAL题库GRE分类
0
GRE VERBAL
GRE
相关试题推荐
Leavingtogocollegewasmyveryfirsttimeawayfromhome,andittookalotofadjustingtonew【C1】______Ididn’thavemymo
Wehadtoput______ourweddinguntilSeptember.
Perhapsmorethananythingelse,scientistsareeagertofindoutifMartianlifeexistedinthepast—orstillexists.【C1】______
LivinginthecentralAmericandeserthasitsproblems,______obtainingwaterisnottheleast.
Ifxis1,2,3or4andyis2,4,8or16,thentheproductxycanhavehowmanydifferentpossiblevalues?
Thefactthatsuperiorservicecangenerateacompetitiveadvantageforacompanydoesnotmeanthateveryattemptatimproving
Intendedprimarilytostimulatefamilysummertravel,thenewairfare,whichallowsbothanadultandachildtoflyforthepri
Developingnationsinvariouspartsoftheworldhaveamassed$700billionindebt;atstake,shouldasignificantnumberofthe
TRICKLE:GUSH::
Thecurrentpenchantfor(i)____aproductbydenigratingarival,namedintheadvertisementbybrandname,seemssomewhat(ii)
随机试题
Whentwohandsmeet,wepassonsomethingofourselves.After【C1】______toMarkTwain,Helen—whowasbothdeafandblind—commente
不属于皮肤黏膜观察的内容是
下列有关股份有限公司股份转让的行为中,不符合《公司法》规定的是()。
下列句子中,加粗的传统礼貌语使用正确的一项是()。
取保候审时犯罪嫌疑人、被告人提出保证人的,就不必交纳保证金。()
2010年7月,党中央、国务院召开了西部大开发工作会议,总结西部大开发10年取得的巨大成就和丰富经验,全面分析国内外形势和西部大开发面临的新机遇、新挑战。关于西部大开发战略,下列表述不正确的是()。
简述学校管理的发展趋势。
Agoodtranslatorisbydefinitionbilingual.Theoppositeisnot【C1】______tree,however.Abornandbredbilingualwillstilln
(1)Doyoueverfeelasthoughyouspendallyourtimeinmeetings?(2)HenryMintzberg,inhisbookTheNatureofManagerial
A、Bettermemories.B、Betterstudyhabits.C、Moreefficientwaysofconveyinginformation.D、Greaterabilitiestodealwithcompl
最新回复
(
0
)