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
The History of the Atomic Bomb On August 2, 1939, just before the beginning of World War II, Albert Einstein wrote to then
The History of the Atomic Bomb On August 2, 1939, just before the beginning of World War II, Albert Einstein wrote to then
admin
2014-09-18
58
问题
The History of the Atomic Bomb
On August 2, 1939, just before the beginning of World War II, Albert Einstein wrote to then President Franklin D. Roosevelt. Einstein and several other scientists told Roosevelt of efforts in Nazi Germany to purify uranium-235, which could be used to build an atomic bomb. It was shortly thereafter that the United States Government began the serious undertaking known then only as "The Manhattan Project". Simply put, the Manhattan Project was committed to expediting research that would produce a viable atomic bomb.
The most complicated issue to be addressed in making of an atomic bomb was the production of ample amounts of "enriched" uranium to sustain a chain reaction. At the time, uranium-235 was very hard to extract. In fact, the ratio of conversion from uranium ore to uranium metal is 500:1. Compounding this, the one part of uranium that is finally refined from the ore is over 99% uranium-238, which is practically useless for an atomic bomb. To make the task even more difficult, the useful U-235 and nearly uselessU-238 are isotopes(同位素), nearly identical in their chemical makeup. No ordinary chemical extraction method could separate them; only mechanical methods could work.
A massive enrichment laboratory/plant was constructed at Oak Ridge, Tennessee. Harold C. Urey and his colleagues at Columbia University devised an extraction system that worked on the principle of gaseous diffusion, and Ernest O. Lawrence (inventor of the Cyclotron) at the University of California in Berkeley implemented a process involving magnetic separation of the two isotopes.
Next, a gas centrifuge was used to further separate the lighter U-235 from the heavier, non-fissionable U-238. Once all of these procedures had been completed, all that needed to be done was to put to the test the entire concept behind atomic fission ("splitting the atom", in layman’s terms).
Over the course of six years, from 1939 to 1945, more than $2 billion was spent during the history of the Manhattan Project. The formulas for refining uranium and putting together a working atomic bomb were created and seen to their logical ends by some of the greatest minds of our time. Chief among the people who unleashed the power of the atom was J. Robert Oppenheimer, who oversaw the project from conception to completion.
Finally, the day came when all at Los Alamos would find out if "The Gadget" (code-named as such during its development) was going to be the colossal dud of the century or perhaps an end to the war. It all came down to a fateful morning in midsummer, 1945.
Which of the following is the least possible reason for the launching of the Manhattan Project?
选项
A、Franklin D. Roosevelt.
B、Nazi Germany.
C、Albert Einstein and other scientists.
D、The Second World War.
答案
A
解析
根据提问,罗斯福是决策者,其他几个选项或多或少足促成曼哈顿计划的原因。It was shortly thereafter that the United States Government began the serious undertaking。
转载请注明原文地址:https://kaotiyun.com/show/TaTK777K
0
专业英语四级
相关试题推荐
Educationofexceptionalchildrenmeansprovisionofspecialeducationalservicestothosechildrenwhoareeitherhandicappedo
It’swidelyagreedthatgirlsgenerallystarttalkingearlierthanboys,andusemorecomplexvocabulary.Whenthey(1)______sch
Foralongtime,newspapershavebeenthechiefmeansbywhichpeoplegetthemselves(1)______.Thenewspapers,daily,evening,a
Althoughinteriordesignhasexistedsincethebeginningofarchitecture,itsdevelopmentintoaspecializedfieldisreallyqui
WhichofthefollowingsentencesDOESN’Tincludepassivevoice?
Thenewcolleague______tohaveworkedinseveralbigcorporationsbeforehejoinedourcompany.[2002]
Thechairmanofthecompanysaidthatnewtechniqueshad______improvedtheirproductionefficiency.[1999]
Televisioncanbeawonderfullearningtool.Thirty-oddyearsago,"SesameStreet,""TheElectricCompany"and"Mr.Rogers’Neig
Thevenerable20-volumeOxfordEnglishDictionarycontainsabout700,000words,buttheeditorsrecentlyrealizedtheyweremiss
Twentyyearsago,atallyoungwomanwithashysmileflubbedherlinesbeforemillionsofpeopleandbecameasuperstar.OnJul
随机试题
顾步汤适用的脱疽证候是
男性,50岁,烧伤患者,烧伤总面积35%,其中Ⅲ度烧伤面积10%。该患者属于烧伤的类型为
工程项目施工质量工作计划主要包括()。
[背景资料]某水泥厂生活区建设项目包括一栋三层食堂和会议室、六层宿舍楼。食堂和会议室的建筑面积为1872.2平方米,宿舍的建筑面积为1450平方米。食堂会议室楼为现浇混凝土框架结构,按6度抗震设防,抗震等级为4级。工程采用天然地基,根据地质勘探资料,
(2014年真题)下列古典名曲与王维的送别诗有关的是()。
容易犯错误是我们人类无法避免的一个弱点,不管科技发展到什么程度,事故总是会在不经意间发生。懂得这个道理,我们就可以“_______”,只有这样,或许我们才能_______应对一切可能出现的麻烦。填入划横线部分最恰当的一项是:
社会医学是指从社会的角度研究与人群的生、老、病、死有关的医学问题,研究社会因素在生命的准备、保护和提高生命质量等不同阶段发挥的综合作用,为医疗卫生事业的管理提供理论依据,为保障人群健康制定相应的卫生目标、政策、策略与措施。根据上述定义,下列不属于社会医学研
《合同法》第51条规定,无处分权的人处分他人财产,经权利人追认或者无处分权的人订立合同后取得处分权的,该合同有效。这一规定属于法律构成要素中的()。
设A,B同时发生,则C发生.证明:P(C)≥P(A)+P(B)-1.
已知矩阵只有一个线性无关的特征向量,那么矩阵A的特征向量是__________.
最新回复
(
0
)