k**l
发帖数: 2966 | 1 come on dude, he said his neutron detector went off scale,
these neutrons are radiation |
|
l******d
发帖数: 1633 | 2 A neutron walks into a bar and asks "how much for a beer?" The bartender
says:"oh my god, a talking neutron!" |
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H********g
发帖数: 43926 | 3 【 以下文字转载自 Military 讨论区 】
发信人: dirtyman (得体男，人称脏生), 信区: Military
标 题: 这篇科幻看起来不错！《龙蛋》（转载） (转载)
发信站: BBS 未名空间站 (Thu Jun 9 16:01:02 2016, 美东)
发信人: dirtyman (得体男，人称脏生), 信区: LeisureTime
标 题: 这篇科幻看起来不错！《龙蛋》（转载）
发信站: BBS 未名空间站 (Thu Jun 9 16:00:50 2016, 美东)
中子星确实会冷却。冷到合适的温度，还可能孕育出生命，甚至文明。
图片来自The Largest Neutron Star in Existence
新生的中子星温度在约1千亿到1万亿度之间。令人发指的高温来自它的前身——恒星热
聚变产生的巨大能量。然而，作为恒星的残骸，中子星本身并没有补充能量的机制，
反而会释放出大量的中微子，带走它的能量。这种无源之水很快就会走向干涸。在短
短数年之间，它的温度就会下降到百万度左右。这时，它仍然以X射线的方式向太空释
放能量，让自己的温度继续下降。
从诞... 阅读全帖 |
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k****u
发帖数: 1686 | 4 六爻基础（必看、必背）
基础口诀；
一看空二看冲，三看刑合衰旺中。四看化出进退死,五看神煞凶不凶。
六看用爻之位置,七看伏神出牢笼。八看反伏吟流泪,九看外应十观容。
（一）、生：相生，金生水、水生木之类。
扶：先帮后为扶 如卯为用神，寅日测，寅能扶卯。
拱 ：后帮先为拱 如寅为用神，卯日测，卯能拱寅。
合 ：合有二合、三合。二合，子与丑合，寅与亥合之类，三合，
三合成局，申子辰合成水局，寅午戌合成火局之类。故凡遇合，须防刑冲克害事。如寅
亥两爻本相和合，若卦中戌土发动，戌土克了亥水，虽合而无用。
二合：1. 合起：月日与卦中静爻相合，谓之合起。静爻被合起，有旺相之意
2. 合住：月日与卦中动爻相合，谓之合住，使动爻不能发动而起作用。
3. 爻与爻合：必须是两爻皆动，有一爻不动也不能成合。两爻俱静更不成合。两爻俱
动而成合，谓之合好，使用神更为旺相有力。
4. 化扶：动爻化出之爻，可以与本动爻合。如卦中丑动化出子水，子丑相合，谓之化
扶，为得化爻扶助之意。
三合成局：（１）卦中三爻都动可成合局。
（２）有两爻动，一爻不动，也可成局，谓之合起
不动之爻。两动包括一明动，一暗动。
（３）内卦... 阅读全帖 |
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w*********r
发帖数: 2192 | 5 http://en.wikipedia.org/wiki/Introduction_to_M-theory
In non-technical terms, M-theory presents an idea about the basic substance
of the universe.
Contents
[hide]
* 1 Background
* 2 Status
* 3 See also
* 4 References
* 5 Books
* 6 External links
Background
In the early years of the 20th century, the atom – long believed to be the
smallest building-block of matter – was proven to consist of even smaller
components called protons, neutrons and electrons, which are known as
... 阅读全帖 |
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q**w
发帖数: 782 | 6 http://physicsworld.com/cws/article/news/48126
Physics World reveals its top 10 breakthroughs for 2011
6th place: Taking the temperature of the early universe
Just after the Big Bang, the universe was a complicated soup of free quarks
and gluons that eventually condensed to form the protons and neutrons we see
today. Sixth place in our top 10 goes to a team of physicists in the US,
India and China that has made the best calculation yet of this condensation
temperature: two trillion degrees Kelvi... 阅读全帖 |
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m**c
发帖数: 2103 | 7 三爽的ssd看上去很烂？
http://www.51nb.com/viewnews-87792.html
TechReport坚持进行的固态硬盘耐用性马拉松试验再次达到关键节点，数据写入量已经
走过300TB，现在各位参赛选手的情况又是如何呢？
最先出现问题的三星840 250GB情况正在持续恶化。100TB的写入后就出现了11个重
新分配扇区，200TB后增至370个，300TB后则达到了833个。三星依然拒绝透露每个扇区
的具体尺寸，如果按照1.5MB的猜测计算那就是1.2GB。
看上去不少，但幸运的是，因为冗余容量更多，用户实际可用的仍未发生变化。
840是唯一一个使用TLC闪存颗粒的，其耐久性存在天然缺陷，因此这一切都并不意
外。
写入不可压缩数据的金士顿HyperX 240GB之前出现了4个重新分配扇区，但此后表
现稳健，没有进一步增多。另一款写入的是可压缩数据，感谢SandForce主控的数据压
缩，实际写入量仅有215TB。
除此之外，Intel SSD 335 240GB也加入了这一行列，出现了1个重新分配扇区。
健康度方... 阅读全帖 |
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s******o
发帖数: 298 | 8 Astronomers think they've found two "quark stars."
by Vanessa Thomas
The Chandra X-ray Observatory has examined two weird objects that should look
like neutron stars, but don't. They appear to be incredibly dense — too dense
even for neutron stars. Astronomers suspect the objects are composed of a new
type of matter made simply of quarks, the most basic subatomic particles
known.
A team of scientists headed by Jeremy Drake of the Harvard-Smithsonian Center
for Astrophysics (CfA) studied RX J1856 |
|
a****n
发帖数: 3082 | 9 Neutron scattering lengths and cross sections
Varley F. Sears
Neutron News, 1931-7352, Volume 3, Issue 3, 1992, Pages 26 – 37 |
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z**h
发帖数: 224 | 10 the difference between the light anb x-ray or neutron is the length scale
they can measure. they all can measure the correaltion. just use small angle
scattering. usulay people use neutron because the contrast is bigger than
x-ray. |
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c***r
发帖数: 4631 | 11 I don't have idea of neutron, but for X-Ray, both of them are about 0.01
degree, if you want to go to such a low angle, the detector could be burned
easily, in the case you can go to such a low angle.
But I don't expect much difference in neutron case.
run
the
layer?
has |
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m***c
发帖数: 1403 | 12 synchrotron source和neutron source是不同的,虽然很多国家实验室
是两个都有的. 但也有一些地方是只有一个的. neutron的更少一些好像. |
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c****e
发帖数: 2097 | 13
condensation does happen, as someone mentioned, in the case of (low T_c)
superconductivity.
in the particular case of neutron stars, the neutron is made of (at least) 3
quarks.
the phase diagram of quark matter under the conditions you're considering
should be answered if people understood very dense quark (gluon) matter.
unfortunately people do not.
also, it seems not clear if in this regime the theory is strongly or weakly
coupled, and or any reliable approximations can be made to understand |
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S**********n
发帖数: 264 | 14 SEM couldn't see single atom. It can only see the rough surface of bulk
materials at a resolution larger than 10X atom sizes. All of the
information comes from very shallow surface (2nm?)
Electrons mostly interact with the potential of atoms. For atomic scale
images formed by TEM/STEM, they could be either understood as projections of
potential or complex inteference pattern mostly determined by point spread
function of lens, which could be comparable even smaller than the atom size.
All of... 阅读全帖 |
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s***e
发帖数: 5242 | 15 by Freeman Dyson
12/2010
In 1946 Subrahmanyan Chandrasekhar gave a talk at the University of Chicago
entitled “The Scientist.” 1 He was then 35 years old, less than halfway
through his life and less than a third of the way through his career as a
scientist, but already he wa reflecting deeply on the meaning and purpose of
his work. His talk was one of a series of public lectures organized by
Robert Hutchins, then the chancellor of the university. The list of speakers
is impressive, and included ... 阅读全帖 |
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e*******n
发帖数: 4912 | 16 101. 1917年，日本数学家挂谷宗一（Kakeya，S(1886-1947)）提出
一个问题：一位武士上厕所时遭到袭击，他只有一根短棒，为了
挡住射击，短棒应旋转360度（支点可以变化），但厕所很小，
问短棒最少要扫过多大面积？
这个问题引起当时很多人的兴趣，如1925年Birkhoff在他
写的The origin, nature, and influence of relativity
一书中提到“近几年日本数学家挂谷宗一提出的问题，是同样令
人感兴趣的问题”
1928年，苏联数学家Besicovitch，Abram Samoilovitch
（1891-1970）解决了这个问题，答案是可以任意小，1960s
Besicovitch在美国数学会就挂谷问题专门做了期科普电影，
有意思的是中间他打了个喷嚏，Besicovitch觉得很不雅，
坚持要求在录像中把这个镜头剪掉，于是现在人们看到的是
镜头突然转向一边，然后是一声闷响....
102. William James seemed to have what seemed vitally important
ideas in d... 阅读全帖 |
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s**********8
发帖数: 25265 | 17 Sterilization (microbiology)
http://en.wikipedia.org/wiki/Sterilization_(microbiology)
From Wikipedia, the free encyclopediaJump to: navigation, search This
article has multiple issues. Please help improve it or discuss these issues
on the talk page.
It may need reorganization to meet Wikipedia's quality standards. Tagged
since March 2008.
It is in need of attention from an expert on the subject. WikiProject
Microbiology may be able to help recruit one. Tagged since December 2010.
Contents [hide... 阅读全帖 |
|
s******o
发帖数: 298 | 18 Astronomers think they've found two "quark stars."
by Vanessa Thomas
The Chandra X-ray Observatory has examined two weird objects that should look
like neutron stars, but don't. They appear to be incredibly dense — too dense
even for neutron stars. Astronomers suspect the objects are composed of a new
type of matter made simply of quarks, the most basic subatomic particles
known.
A team of scientists headed by Jeremy Drake of the Harvard-Smithsonian Center
for Astrophysics (CfA) studied RX J1856 |
|
c****s
发帖数: 5892 | 19 上个月，安省东部地区的一名物理学家突然离奇失踪。目前案件仍无任何进展，这令他的同事感到迷惑不解。
失踪男子名叫Lachlan Cranswick，今年41岁，于1月18日下班后失踪。Cranswick在渥太华(Ottawa)西北部(位于Chalk River)的国家研究委员会的加拿大中子束中心(National Research Council's Canadian Neutron Beam Centre，简称NRC-CNBC)工作。
Cranswick的家位于附近的Deep River，据悉，他的住宅没有上锁，汽车也还在车库里，他的钱包、钥匙和护照也都在。
有媒体报道称，警方已经使出了各种办法，但仍无头绪。
Cranswick的同事Daniel Banks说，Cranswick的失踪太离奇，之前没有人发现他有什么不对的地方。这名同事还说，Cranswick是一个安全警觉性很高的人，如果不带手机和GPS他是不会出门的。“如果他的朋友喝多了，他会给他们做完酒测再准他们离开。”“他就是这么一个认真的人，所以说他不太可能会去冒不必要的险。”
Cranswick是一名澳大利亚移民，在英国辞职后 |
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m***y
发帖数: 14763 | 20 hehe, Thorium-based requires continual supply of neutrons, and thus runs on
a negative-feedback. If anything went wrong, the chain reaction is stopped
automatically.
Therefore, there won't be 核弹爆炸. But still, there would be radioactive
leakage. Even in this case, Thorium is better, because it barely resolves in
water. |
|
a*****o
发帖数: 209 | 21 Positron emission or beta plus decay (β+ decay) is a particular type of
radioactive decay, called beta decay, in which a proton is converted to a
neutron, and it releases a positron and a neutrino. |
|
s********e
发帖数: 13723 | 22 打俄罗斯，TG最需要的是NEUTRON JAMMER |
|
i***a
发帖数: 195 | 23 还是让我这专业人士来解答一下吧：
核放射物质主要通过释放核粒子（NEUTRON和GAMMA）来产生对人的影响，除了粒子数量
（取决于距离、时间，传播途径等因素）外，还主要取决于两个方面：一个是衰变强度
，一个衰变能量。衰变强度指的是一秒钟产生多少个例子，一般是以居里为单位，1Ci=
3.7x10^10 Bq, 表示一秒钟产生3.7x10^10个粒子。每个粒子的能量用兆电子伏(MeV）
来衡量。一般而言，同等衰变强度下，能量越高的粒子对人体伤害越大，中子比gamma
伤害更大，是10-20倍之多，原因是高能中子在穿透人体，与人体元素发生作用，产生
细胞变异。
一般实验室用的源都在铅盒里保存，原因是铅（Pb)具有强大的密度能阻碍粒子射出，
因此严格防备的实验室对人体伤害不大。
而核电站辐射产生的核放射元素，通过风，雨，地下水，河流，尘土等等入侵人体后，
其中包含各种复杂的粒子源，半衰期长的对人体影响更大，最长的有几百年，比如反应
堆产物之一Americium-241（半衰期为432年），也就四说过了432年，其核衰变强度才
降低到原来的一半,通过ALPHA衰变，该物质可产生5.5MeV的G... 阅读全帖 |
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i***a
发帖数: 195 | 24 核放射物质主要通过释放核粒子（NEUTRON和GAMMA）来产生对人的影响，除了粒子数量
（取决于距离、时间，传播途径等因素）外，还主要取决于两个方面：一个是衰变强度
，一个衰变能量。衰变强度指的是一秒钟产生多少个例子，一般是以居里为单位，1Ci=
3.7x10^10 Bq, 表示一秒钟产生3.7x10^10个粒子。每个粒子的能量用兆电子伏(MeV）
来衡量。一般而言，同等衰变强度下，能量越高的粒子对人体伤害越大，中子比gamma
伤害更大，是10-20倍之多，原因是高能中子在穿透人体，与人体元素发生作用，产生
细胞变异。
一般实验室用的源都在铅盒里保存，原因是铅（Pb)具有强大的密度能阻碍粒子射出，
因此严格防备的实验室对人体伤害不大。
而核电站辐射产生的核放射元素，通过风，雨，地下水，河流，尘土等等入侵人体后，
其中包含各种复杂的粒子源，半衰期长的对人体影响更大，最长的有几百年，反应堆产
生的辐射物质种类极其之多，比如反应堆产物之一Americium-241（半衰期为432年），
也就四说过了432年，其核衰变强度才降低到原来的一半,通过ALPHA衰变，该物质可产
生5.5MeV的... 阅读全帖 |
|
|
a***x
发帖数: 1303 | 26 The current method of extracting energy from fusion is a joke. The energy
extractable from the fusion is the neutron heating, a too fancy idea. |
|
h****u
发帖数: 788 | 27 老美二战之后的总统基本上都是服过军役：
Dwight D. Eisenhower, commander of US force in Europe during WWII
J.F.K, navy officer served in pacific front in WWII
Lyndon B. Johnson, silver star in WWII
Richard Nixon, navy logistical officer in WWII
Gerald Ford, naval aviator in WWII
Carter, navy officer served in the nuclear sub fleet of early days.
Reagan, served in active duty during WWII.
Bush Senior, naval aviator, flew combat missions in pacific front of WWII
Clinton, never served
Bush Junior, air force reserve for... 阅读全帖 |
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i*****g
发帖数: 11893 | 28 我靠，阿3哥的技术
好莱坞赶紧上，赶紧采访，neutron可以加热融化地核，又可以拍一个2112了 |
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H****g
发帖数: 14447 | 29 再来谈你提到的第二点。
首先，马克思提出人类社会的阶级属性，具体就是说，人是社会关系的总和。这个很好
理解，比如说，咱们买买提上的屁歪，就常常津津乐道自己的社会关系，可谓是：“中
南海倒茶，皇城根开车，天桥下说书，买卖提卖艺”。
而这个阶级属性由什么决定呢，就是一个人的社会经济地位了。这里需要提醒的是，不
同理论体系的用词，字面一样，但是含义未必一样，所以不能自由转换的。比如说马克
思提到的经济基础，和Bourdieu的经济资本，就不是一个概念。我们不能根据Bourdieu
将资本划分为经济资本社会资本文化资本，来批判马克思的经济基础不包含社会资本文
化资本。在我看来，是不是理解为Bourdieu将经济基础进一步细分了更贴切呢？就如同
物理学，开始是分子，原子，后来又分成了proton，neutron，electron，后来的后来
呢，又发现proton这些都是quark组成的。现在呢，string theory又认为quark就是
string。我们能不能根据后人的进展来推翻前者的理论呢？我看不能。就好像我们不能
因为我们今天使用了Win7，就认为Win98一无是处一样。 |
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f*u
发帖数: 5923 | 30 要说不热门，为什么影视小说都要说哥德巴赫猜想呢？连悬赏都有。
To generate publicity for the novel Uncle Petros and Goldbach's
Conjecture by Apostolos Doxiadis, British publisher Tony Faber offered a $1,
000,000 prize if a proof was submitted before April 2002. The prize was not
claimed.
The television drama Lewis featured a mathematics professor who had won
the Fields medal for his work on Goldbach's conjecture.
Isaac Asimov's short story "Sixty Million Trillion Combinations"
featured a mathematician who suspected... 阅读全帖 |
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h******i
发帖数: 661 | 31 你们学校ap能发这么多paper?
1989
Cosmological implications of quasar-galaxy associations, L.Z.Fang, Y.Q.Chu
and X.F. Zhu, Mod. Phys. Lett., 4, 887.
Geometrical optics in an inhomogeneous universe, L.Z.Fang and X.P.Wu,
Chinese Phys. Lett., 6, 233.
Quasar clustering and its cosmological implication, L.Z.Fang, Inter. J. Mod.
Phys. A4, 3477.
L'Osservatorio astronomico di Pechino: la sua storia, il presente, L.Z.Fang,
Scienza e Tecnica, Annuario della EST 88/89 404.
Overview on the frontier of high energy astr... 阅读全帖 |
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L*******o
发帖数: 895 | 32 1. Isaac Newton - English. Quantified and Qualified laws of motion and
gravity. Invented the reflecting telescope. Explained the concept of light
dispersion and co-invented the Calculus.
2. Albert Einstein - German/Swiss/American - Developed Theories of Special
and General Relativity. Described Brownian Motion. Nobel Prize winner for
his work on the photoelectric effect. Showed mass-energy equivalence.
3. Galileo Galilei - Italian - Discovered the law of Uniformly accelerated
motion. Improved on... 阅读全帖 |
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s********n
发帖数: 2939 | 33 为什么一帮人就喜欢动嘴皮子不喜欢动手狗一下？明明说了是Fe4[Fe(CN)6]3，哪来的
钾？
https://en.wikipedia.org/wiki/Prussian_blue
Prussian blue
From Wikipedia, the free encyclopedia
This article is about the pigment. For the musical duo, see Prussian Blue.
See also: Midnight blue
Prussian blue
IUPAC name[hide]
Iron(II,III) hexacyanoferrate(II,III)
Other names[hide]
Berlin blue
Ferric ferrocyanide
Ferric hexacyanoferrate
Iron(III) ferrocyanide
Iron(III) hexacyanoferrate(II)
Parisian blue
Identifiers
CAS number 14038-43-8
PubChem ... 阅读全帖 |
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m********5
发帖数: 17667 | 34 http://www.youtube.com/watch?v=aHnQWPjS7aE
At the recent Google “Solve for X” conference on February 7, Lockheed
Martin's long-term R&D department (“Skunk Works”) announced they are
working on a compact fusion reactor. With what seems a 4th generation
prototype called "T4", the aerospace giant says to have developed a high
beta configuration, which allows a compact reactor design and faster
development timeline.
Lockheed Martin and its infamous "Skunk Works" top-secret technology
development gro... 阅读全帖 |
|
p****s
发帖数: 3184 | 35 “中央集权制大一统政体”有个屁“科学性”和“合理性”。
中央集权制，归根到底是基于tree数据结构的算法，中央就是root，蚁民是leafs，中
间的等级官僚是各层intermediates。
tree这种建模是万能的吗？哪个家伙万事都用tree来建模解决问题这人肯定就是个大傻。
network才是比tree更本质的对世界上事物的建模。
人体是细胞网络network of cells，人脑是神经元网络network of neutron cells。
互联网是路由器构成的网络network of routers，社会是人构成的网络network of
persons。
树也是网络的一种。
网络里情况较复杂，树只是其中很小的一类，根本没什么代表性。就和hypercube这种
网络一样，是比较极端的特例，可能在某些情况下其个别性能最佳（比如hypercube各
项指标都是均衡的O(lgn))，但总体性能未必好、甚至是坏成狗屁都很有可能。
举个例子，robustness和performance最好的name lookup server的结构是hypercube(
如CAN, Chord等其实... 阅读全帖 |
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O*******d
发帖数: 20343 | 36 Radiation-hardening techniques[edit]
Physical:
Hardened chips are often manufactured on insulating substrates instead of
the usual semiconductor wafers. Silicon dioxide (SOI) and sapphire (SOS) are
commonly used. While normal commercial-grade chips can withstand between 50
and 100 gray (5 and 10 krad), space-grade SOI and SOS chips can survive
doses many orders of magnitude greater. At one time many 4000 series chips
were available in radiation-hardened versions (RadHard).[3]
Bipolar integrated ... 阅读全帖 |
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d*b
发帖数: 21830 | 37 你来说说100GeV的cosmic muon怎么屏蔽？知道muon的stopping power是多少么？
宇宙线的屏蔽跟裂变产品的屏蔽不一样，前者的目的是如何避免高能muon造成的运算
random error,后者主要是防止neutron activation后产生的damage.
无论如何，radiation damage是个非常缓慢的过程，一般detector的radiation damage
都要好几年后才完全死掉。宇航级的芯片的辐射防护主要目标是提高运算的可靠性，而
不是整体寿命。 |
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d*b
发帖数: 21830 | 38 NAA（neutron activation analysis）是最常用的办法，一般情况下只要你接触过爆炸
物就能查出来，如果NAA都查不出来的话，那肯定是国家级的恐怖分子了
机场的check in行李scanner都有data recorder的，事后分析也可以发现究竟有没有爆
炸物，除非机场有人照应。 |
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d*b
发帖数: 21830 | 39 可以，现在机场普遍使用NAA(neutron activation analysis),用10MeV以上的gamam射
线照射激发产生中子（中子的binding energy是8MeV),然后分析产生的同位素频谱，基
本上没有炸弹可以逃脱检查的。
所以现在漏网的都是些随身行李，比如水瓶，鞋底炸弹等等。因为随身行李不能做NAA，
除了NAA外，机场也有便携式ion scanner, 用于手，箱子外壳的爆炸物残留痕检。一般
认为，如果没有内应，或者管理问题，炸弹基本不可能过安检，看看美国近年来的成果
就知道了。 |
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S******8
发帖数: 24594 | 40 老方到美国后发的文章列表，你自己看吧：
1990
174. Biased clustering in a universe with hot dark matter and a cosmic
string, L.Z.Fang, S.P.Xiang and L.Yan, Astr. & Astrophys. 233, 1.
175. Periodicity of redshift distribution in a T-3 universe, L.Z.Fang, Astr.
& Astrophys. 239, 24.
176. An upper limit to quasar's peculiar velocity, L.Z.Fang, Y.Q.Chu, X.F.
Zhu and L.F. Wang, Inter. J. Mod. Phys., 5, 2993.
177. Quasar pair and quasar's peculiar velocity, L.Z.Fang, Developments in
general relativity, astrophysics and qu... 阅读全帖 |
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d*b
发帖数: 21830 | 41 ion scanner, 物理里叫neutron activation,各大机场都有这设备，原则上只要你当天
手接触过火柴就能被检出。 |
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g**1
发帖数: 10330 | 42 23岁陆生朱树楠 车祸亡
记者王湛／旧金山报导
August 22, 2015, 6:00 am 1140 次
朱树楠生前喜欢驾着爱车跑山路。（图片由戴伊提供）
朱树楠生前喜欢驾着爱车跑山路。（图片由戴伊提供）
年仅23岁的俄勒冈大学中国留学生朱树楠（Shunan Zhu）于15日晚8时40分死于一场车
祸。家属赶办签证后已启程前往美国。朱树楠生前爱好业余赛车，同好已决定于29日举
行悼念活动，驾车走朱树楠生前最爱开的山路。
车祸发生地点位于俄勒冈州Tillamook县，靠近Upper Nestucca River路和Bible Creek
路交汇路口。31岁的赛车同好巴塞罗（Joel Pacello）驾驶1989年款日产240SX轿跑车
，高速行使撞上路肩。坐在旁边的朱树楠卡在车中当场死亡。巴塞罗被送往Tillamook
县医疗中心，县警局初步判定事故原因是酒驾。
Tillamook县警麦格劳（Gordon Mcgraw）表示，巴塞罗涉嫌酒驾和二级过失杀人，已被
暂时收押，案件目前仍在调查。县警局已从校方得到消息，朱树楠的父亲将于本周末抵
达俄勒冈州处理后事。初步调查，巴塞罗和朱树楠... 阅读全帖 |
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G*******n
发帖数: 6889 | 43 先杀光老酱，二上cyber，随后neutron蛋 |
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w*j
发帖数: 6104 | 44 不会是假的吧
Irvine, Calif., August 15, 2016 – Recent findings indicating the possible
discovery of a previously unknown subatomic particle may be evidence of a
fifth fundamental force of nature, according to a paper published in the
journal Physical Review Letters by theoretical physicists at the University
of California, Irvine.
“If true, it’s revolutionary,” said Jonathan Feng, professor of physics &
astronomy. “For decades, we’ve known of four fundamental forces:
gravitation, electromagnetism, and... 阅读全帖 |
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d*b
发帖数: 21830 | 45 ADS的理论背景就是原子物理里的neutron activation, 原子核里的质子和中子的
binding energy大致是8MeV,超过8MeV就能把原子核里的质子，中子轰出来，原来的靶
变成低半衰期的原子快速衰变，这个理论无数地方用，比如机场码头侦察爆炸物的ion
scanner,很多就是用8MeV以上的粒子轰，分析产生的低半衰期的气体，比如氧13，从而
分析爆炸物含量。
当然，spend fuel很多，反应截面很小，这玩意效率不会很高，不过原子物理的玩意，
哪个效率高了？
这事从本质上说就是西方现在真的没有钱，根本搞不了上规模的R&D，除了台南嘴炮还
是一如既往的强大外。
义。 |
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r*s
发帖数: 2555 | 46 【 以下文字转载自 Joke 讨论区 】
发信人: rbs (jay), 信区: Joke
标 题: 诺委会太不像话了
发信站: BBS 未名空间站 (Wed Oct 4 10:23:52 2017, 美东)
尼玛87篇参考文献就不能加一篇施教授或能教授的CNS？
References
1. Ruska, E., Nobel Lectures, Physics 1981-1990, Tore Frängsmyr and
Gösta Ekspong, Eds. (1993) World Scientific Publishing, Singapore
2. Marton, L. (1934) Electron microscopy of biological objects. Nature
133, 911-911
3. Althoff, T., Mills, D. J., Popot, J. L., and Kühlbrandt, W. (2011)
Arrangement of electron transport chain compone... 阅读全帖 |
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S*********g
发帖数: 24893 | 49 【 以下文字转载自 Stock 讨论区 】
发信人: StephenKing (金博士), 信区: Stock
标 题: 市面上流通1358种电子货币，包括ByteCoin
发信站: BBS 未名空间站 (Fri Dec 15 00:59:47 2017, 美东)
# Name Symbol Market Cap Price Circulating Supply Volume (
24h) % 1h % 24h % 7d
1
Bitcoin BTC $290,617,804,480 $17,358.40 16,742,200 $15,
825,500,000 -0.36% 5.62% 3.15%
2
Ethereum ETH $63,827,563,522 $662.47 96,348,146 $3,723,
910,000 -0.48% -10.50% 52.62%
3
Bitc... 阅读全帖 |
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s*****V
发帖数: 21731 | 50 https://www.math.columbia.edu/~woit/wordpress/
今年是费曼诞辰100周年，纪念文章里面大部分都是赞扬费曼的天才，但是也有一些不
同的声音。
夸克发现者盖尔曼的采访，回忆他才去caltech的时候很崇拜费曼，但是发现很难跟费
曼合作。
One of your best-known interactions was with Richard Feynman at Caltech.
What was that like?
We had offices essentially next door to each other for 33 years. I was very,
very enthusiastic about Feynman when I arrived at Caltech. He was much
taken with me, and I thought he was terrific. I got a huge kick out of
working with him. He was funny, amusing, brillia... 阅读全帖 |
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