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
39
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
InAmericaalone,tippingisnowa$16billion-a-yearindustry.Arecentpollshowedthat40%ofAmericans(1)______thepractic
InAmericaalone,tippingisnowa$16billion-a-yearindustry.Arecentpollshowedthat40%ofAmericans(1)______thepractic
It’swidelyagreedthatgirlsgenerallystarttalkingearlierthanboys,andusemorecomplexvocabulary.Whenthey(1)______sch
______asapsychologistwithallkindsofpeople,I’velearnedthatsuccessfulpeoplearen’tnecessarilytheoneswiththegrea
TherearemanytheoriesaboutthebeginningofdramainancientGreece.Theonemost(1)______acceptedtodayisbasedontheass
Althoughinteriordesignhasexistedsincethebeginningofarchitecture,itsdevelopmentintoaspecializedfieldisreallyqui
Manymanufacturerswereaccusedofconcentratingtooheavilyoncostreduction,oftenatthe______ofthequalityoftheirprodu
TheClarkshaven’tdecidedyetwhichhotel______.
Letmespeakfirsttoparents.Youaretheoneswhoplant,orfailtoplant,theseedsofcharacterinyourchildren.Tryfromt
Theboytiptoedoutoftheroomandheadedfortheswimmingpoolwithouthisfather’s
随机试题
Wehavecometothinkofteenagersasabreedapart—askanyparentofone.Butasadriverofculture,asaconsumerniche,asa
在谈判人员的成才过程中,基本素质的奠定主要依靠()
对洋务派兴办洋务事业的指导思想最先作出比较完整表述的是()
Let’sthinkofasituation______thisidiomcanbeused.
其胎位为应采取的措施是
一般情况下,耐火等级为一、二级的高层民用建筑之间的防火间距不应小于()m。
市盈率的主要决定因素有()。
()是指商业银行根据全部贷款余额按一定比例计提,用于弥补尚未识别的可能性损失的准备。
法人的成立应当具备下列条件()。
What’sAmericanpublic’sviewtowardsguncontrol?
最新回复
(
0
)