z**********g
发帖数: 16 | 1 Repulsion Particle Hypothesis
: Zhuang Yilong
Shanghai Institute of Science & Technology Management
Jiading District of Shanghai, 201800, China
Abstract: The theory of “ Repulsion Particle Hypothesis” is a new theory
of matter interactions. In contrast to Newtons universal gravitation that
the apple drops from the tree, this hypothesis can be called the universal
repulsion theory tha... 阅读全帖 |
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z**********g
发帖数: 16 | 2 Discussing The Existence of “repulsion particle” And Its Significance
Zhuang Yiliong
Shanghai Institute of Science and Technology Management
Abstract:This report has advanced a assume about the existence of “
repellention” by a kind of new idea. Beginning with this, I have explained
more successfully some import theory questions in the area of the present
physics, cosmology and philosophy ect. At same time a few of new reasons
have been raised But this is only rough idea of physica... 阅读全帖 |
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e**n
发帖数: 5876 | 3 欢迎你来讨论. 那么我们就先定义: 通光量, 即单位时间内单位面积接受的photon数
目. (photon/each unit of area of sensor) . 总通光量, 即单位时间内内整个
sensor接受的photon总和. (photon/each unit of area of sensor * number of
units).
如你所说, "f1.8 on RX100 has the same photon/square inch sensor as f1.8 on
LX7." "F-stop这个概念， 在不同的相机上通光量可以比较". 这也就是把FF相机镜头
接在APS或者43上, f-stop值不变, i.e. 同一镜头的f1.4在ff的上的photon/square
inch sensor和它转接在APS或者43上的f1.4是一样的.
相信这个大家理解都是一致的. 那么下面说等效光圈和总通光量的关系.
我再用一下前面举的例子证明一下: 不同sensor大小,只要等效光圈一样,那么总通光量
就一样:
LX7和RX100的转换关系不好算. 就用FF和43... 阅读全帖 |
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D**s
发帖数: 6361 | 4 【 以下文字转载自 USANews 讨论区 】
发信人: chali1234 (查理), 信区: USANews
标 题: 别瞎传谣H1B 11万工资线了，看看Trump自己公司H1B申请情况
发信站: BBS 未名空间站 (Tue Nov 22 14:31:50 2016, 美东)
2013年以后46个，平均工资才7万，低的有3万多的。超过10万的只有2个。
http://h1bdata.info/index.php?em=trump&job=&city=&year=All+Years
New Click to see up to date H1-B filings from trump
46 Records, Median Salary $70000
Employers (12) Job Titles (29) Cities (16) Years (5)
<100k91.304347826087% Complete (success) 100k-150k4.3478260869565% Complete
(success) 150k-200k2.1739130434... 阅读全帖 |
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c*******4
发帖数: 1874 | 5 谁说trump从来不办h1b 又造谣
New Click to see up to date H1-B filings from trump
46 Records, Median Salary $70000
Employers (12) Job Titles (29) Cities (16) Years (5)
<100k91.304347826087% Complete (success) 100k-150k4.3478260869565% Complete
(success) 150k-200k2.1739130434783% Complete (warning) >200k2.1739130434783%
Complete (danger)
EMPLOYER
JOB TITLE
BASE SALARY
LOCATION
SUBMIT DATE
START DATE
CASE STATUS
TRUMP NATIONAL GOLF CLUB ASSISTANT GOLF COURSE SUPERINTENDENT 37,700
COLTS NECK, ... 阅读全帖 |
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c*******4
发帖数: 1874 | 6 2013年以后46个，平均工资才7万，低的有3万多的。超过10万的只有2个。
http://h1bdata.info/index.php?em=trump&job=&city=&year=All+Years
New Click to see up to date H1-B filings from trump
46 Records, Median Salary $70000
Employers (12) Job Titles (29) Cities (16) Years (5)
<100k91.304347826087% Complete (success) 100k-150k4.3478260869565% Complete
(success) 150k-200k2.1739130434783% Complete (warning) >200k2.1739130434783%
Complete (danger)
EMPLOYER
JOB TITLE
BASE SALARY
LOCATION
SUBMIT DATE
START DATE
CASE STATUS
TRUMP... 阅读全帖 |
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d**********u
发帖数: 4124 | 8 ☆─────────────────────────────────────☆
yuanfeiwo (原非我|梨园深) 于 (Sat Nov 15 15:51:26 2008) 提到:
从别处转载来的，可能统计并不完全
http://www.ncku1897.net/post/topic.aspx?tid=2763619
生物医学：
Cell. Vol 134, 279-290, 25 July 2008 (IF=29.887)
Physiol Rev 88: 1491–1545, 2008 (IF=29.6)
Nat Rev Neurosci. 2008 Aug;9(8):646-54. (IF=24.52)
Circulation. 2008, doi: 10.1161/CIRCULATIONAHA.107.761932 (IF=12.755)
Gastroenterology. 2008 Apr;134(4):998-1006. (IF=11.673)
Mol Psychiatry. 2008 Jan 8 [Epub ahead of print] (IF=10.9)... 阅读全帖 |
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c****r
发帖数: 1960 | 11 Subject: Graduate Positions at the National University of Singapore and
University of Delaware in Nanophotonics (November 1 2012 deadline)
Dear Potential Students,
The Nanophotonics group at the National University of Singapore is
recruiting for a total of ten fully-funded PHD positions this year, and we
are recruiting for multiple funded positions at our US organization at the
University of Delaware.
Please note there is a November 1 deadline - see the end of this message for
more information.... 阅读全帖 |
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b***z
发帖数: 2723 | 12 The following is a breakdown of the energetics of the photosynthesis process
from Photosynthesis by Hall and Rao:[5]
Starting with the solar spectrum falling on a leaf,
47% lost due to photons outside the 400–700 nm active range (chlorophyll
utilizes photons between 400 and 700 nm, extracting the energy of one 700 nm
photon from each one)
30% of the in-band photons are lost due to incomplete absorption or photons
hitting components other than chloroplasts
24% of the absorbed photon energy is los... 阅读全帖 |
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n*********2
发帖数: 357 | 13 <<我觉得你的理解错了。量子态并不是不可以复制，但是一旦复制，就很容易被对方发
现>>
It might be easier to debate this in English. First, let me rush to say that
I am not a physicist and my understanding of QKE might be flawed.
Let's use photon as an example, since photon has been widely used in a
simplified version of quantum key exchange (QKE). In an oversimplified case,
photon can be either rectilinear (with an angle of 0 or 90) or diagonal (
with an angle of 45 or 135); this rectilinear/diagonal property is called
its orientation. ... 阅读全帖 |
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e**n
发帖数: 5876 | 14 我再试着解释一下总通光量和画质的关系, 你看看这次能不能理解了
还是用ff和43做例子, 转换系数好算哈. 假设单位时间ff的sensor在f4光圈总共接受
到了1000个photon, 43在f2, 等效光圈f4, 同样时间内也接受到了1000个photon. 到
目前你能fellow我, 对吧. 那么假设ff和43都有100个像素, (像素少了点, 但好算哈),
43的面积是ff的1/4, 43那100个像素的密度和ff的不一样. 但是用总通光量就不用考
虑这些, 1000个photon, 100个像素, 所以不论是ff还是43,每个像素都接受到了10个
photon, 每个像素的photon数一样, SNR也一样, 像素总量一样, 画质也就一样.
当然, 这个1000个photon可以分给200个像素, 那每个像素分到5个photon, 像素总数增
加, 解析度可能增加, 但是每个像素的SNR下降了. 和做100个像素画质差不多, trade
off.
恩.... 我这么解释不知道你明白了没有... 根本的根本, 从理论上讲, 相机芯片需
要photon来做信号处... 阅读全帖 |
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c****t
发帖数: 19049 | 15 THE GIST
Hong Kong physicists say they have proven a single photon cannot travel
faster than the speed of light.
This demonstrates that time travel is impossible, they say.
Hong Kong physicists say they have proved that a single photon obeys
Einstein's theory that nothing can travel faster than the speed of light --
demonstrating that outside science fiction, time travel is impossible.
The Hong Kong University of Science and Technology research team led by Du
Shengwang said they had prov... 阅读全帖 |
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l***d
发帖数: 1798 | 16 这个龚 算是老学霸了
查了一下肖， 龚co-corresponding author的文章
净挑好文章，当co-corresponding authors
2010年龚有三篇只是署名，
估计肖被警告了
以后基本都是co-correspond authors
国内这种欺负 青椒 太tnnd恶心了
2013
Yong-Chun Liu, Yun-Feng Xiao*, You-Ling Chen, Xiao-Chong Yu, and Qihuang Gon
g*, "Parametric Down-Conversion and Polariton Pair Generation in Optomechani
cal Systems," Phys. Rev. Lett. 111(8), 083601 (2013).
Linbo Shao, Xue-Feng Jiang, Xiao-Chong Yu, Bei-Bei Li, William R. Clements,
Frank Vollmer, Wei Wang, Yun-Feng Xiao*, and Qihuang Gong*, "De... 阅读全帖 |
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G***Y
发帖数: 9698 | 17 发信人: Alres (阿瑞斯), 信区: Ski
标 题: 这里可以卖 SKI么？K2 A.M.P Photon Skis with Marker M3 10.0 Bindings
2012
发信站: BBS 未名空间站 (Sun Feb 5 22:55:12 2012, 美东)
160cm
K2 A.M.P Photon Skis with Marker M3 10.0 Bindings 2012
K2 A.M.P. Photon Skis 2012: For 2012, the K2 A.M.P. Photon Skis carry a
powerful force of energy with the forgiveness and control of All-Terrain
Rocker™, combined with new Glass Web and M3 binding system. The Photon
has the power to take recreational skiers to every corner of the resort,
... 阅读全帖 |
|
N*L
发帖数: 4 | 18 【 以下文字转载自 EE 讨论区 】
发信人: NSL (懒的想), 信区: EE
标 题: 转一个Thorlab在上海的工作机会
发信站: BBS 未名空间站 (Wed Jun 26 16:08:38 2013, 美东)
Title: Photonics Lab Specialist
Location: Shanghai
The person that fills this newly created position will be responsible for
designing and improving laboratory training programs in Thorlabs’ Training
Center located in Shanghai. He/she will work with application engineers to
design experiments dedicated to conduct photonics lab knowledge to our
customers as a value-added service. He/sh... 阅读全帖 |
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U*****g
发帖数: 366 | 19 My area: semiconductor device and physics / electrical engineering
CV:
QIUGUI ZHOU
Email: q**[email protected]
Phone: 1+(434) 243-2147
===========================================================================
EDUCATION
UNIVERSITY OF VIRGINIA
Charlottesville, VA
Ph.D. in Electrical Engineering
2011
UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA(中国科学技术大学)
Hefei, CHINA
Master of Science in Optics ... 阅读全帖 |
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t******0
发帖数: 629 | 20 我想问一下photonics这一行找工作的方法是什么样的呢？
大侠看我的理解对不对：
（1），Photonics这一行都要求5+years working experience,而且学位高比较好，所
以适合读PhD，把PhD这5年算到工作经验里去，fresh master甭想了，是吗？
（2），Photonics 这一行有了PhD学位之后，才算是有资格找相关工作了（排除
Photonics master硬转行当码工的情况）。
（3），公司基本上都在CA和TEXAS，别的学校的毕业生要勤买飞机票。
（4），面试怎么面啊？读CS的PhD喜欢抱怨“论文对于找工作，是浮云，关键是skill,
看看面试题，算法都背下来，答题时候得100分，就找到工作了”，但是Photonics是
不是这样呢？？？肯定不是吧，需要的知识很杂，没法出一些统一的题型来考，是不是
就看论文，谈话，面试者主观断定你有没有货？？
期待Photonics方面的过来人，指点迷津。。。
A。如果面试是考官主动了解你的辉煌历史，然后下结论，那么咱就心无旁骛地好好搞
研究，出论文。
B。如果面试是考官出一堆标准题让你答，然后下结论，... 阅读全帖 |
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N*L
发帖数: 4 | 21 【 以下文字转载自 EE 讨论区 】
发信人: NSL (懒的想), 信区: EE
标 题: 转一个Thorlab在上海的工作机会
发信站: BBS 未名空间站 (Wed Jun 26 16:08:38 2013, 美东)
Title: Photonics Lab Specialist
Location: Shanghai
The person that fills this newly created position will be responsible for
designing and improving laboratory training programs in Thorlabs’ Training
Center located in Shanghai. He/she will work with application engineers to
design experiments dedicated to conduct photonics lab knowledge to our
customers as a value-added service. He/sh... 阅读全帖 |
|
A***s
发帖数: 109 | 22 http://www.mitbbs.com/article_t0/NewYork/32497793.html
中城地区可以当面交易
160cm
K2 A.M.P Photon Skis with Marker M3 10.0 Bindings 2012
K2 A.M.P. Photon Skis 2012: For 2012, the K2 A.M.P. Photon Skis carry a
powerful force of energy with the forgiveness and control of All-Terrain
Rocker™, combined with new Glass Web and M3 binding system. The Photon
has the power to take recreational skiers to every corner of the resort,
continuously expanding your comfort zone with its stability and forgiveness.
T... 阅读全帖 |
|
A***s
发帖数: 109 | 23 http://www.mitbbs.com/article_t0/NewYork/32497793.html
中城地区可以当面交易
160cm
K2 A.M.P Photon Skis with Marker M3 10.0 Bindings 2012
K2 A.M.P. Photon Skis 2012: For 2012, the K2 A.M.P. Photon Skis carry a
powerful force of energy with the forgiveness and control of All-Terrain
Rocker™, combined with new Glass Web and M3 binding system. The Photon
has the power to take recreational skiers to every corner of the resort,
continuously expanding your comfort zone with its stability and forgiveness.
T... 阅读全帖 |
|
c****t
发帖数: 19049 | 24 Some particles such as photons and electrons, when brought together and then
separated, can become “entangled” and exist in the same quantum
mechanical state.
This quantum mechanical state, prior to any form of measurement, possesses
indefinite properties such as position in space, spin, and polarization.
Such properties remain indefinite until they are measured, at which point
they take on definite values such as a particular location in space or a
clockwise spin. After one such entangled parti... 阅读全帖 |
|
N*L
发帖数: 4 | 25 Title: Photonics Lab Specialist
Location: Shanghai
The person that fills this newly created position will be responsible for
designing and improving laboratory training programs in Thorlabs’ Training
Center located in Shanghai. He/she will work with application engineers to
design experiments dedicated to conduct photonics lab knowledge to our
customers as a value-added service. He/she will also help develop the oral
presentation skills of the application engineers group. The successful
candidat... 阅读全帖 |
|
N*L
发帖数: 4 | 26 【 以下文字转载自 EE 讨论区 】
发信人: NSL (懒的想), 信区: EE
标 题: 转一个Thorlab在上海的工作机会
发信站: BBS 未名空间站 (Wed Jun 26 16:08:38 2013, 美东)
Title: Photonics Lab Specialist
Location: Shanghai
The person that fills this newly created position will be responsible for
designing and improving laboratory training programs in Thorlabs’ Training
Center located in Shanghai. He/she will work with application engineers to
design experiments dedicated to conduct photonics lab knowledge to our
customers as a value-added service. He/sh... 阅读全帖 |
|
z**********g
发帖数: 16 | 27 继续发表有关斥力子的文章，请指正。
“斥力子理论”对物理学的影响1
庄一龙
近年来，由中国学者创立的“斥力子理论”，经过中国科学院《科技促进发展》《
科技成果管理与研究》、《科技中国》、《中国科技财富》、《中国科技成果》等主流
科技杂志报导后，引起了学术界广泛重视。那么，这一理论究竟有那些观点震动了学术
界，值得人们如此关注呢？
“斥力子理论” 是一种新物质作用理论，实际上也是一种物理哲学理论。它的代
表性文章是《论“斥力子”的存在及其意义》，另外还包括《相对性效应和牛顿定律的
本质》、《物理学中精细结构常数的理论推导与解释》等几十篇论文。同牛顿的苹果从
树上掉下来的万有引力理论相对应，这是一个可称作“苹果如何转移到树上去的‘万有
斥力’理论”。该理论认为，地面的物体一旦动起来，不管方向如何，都具有一种挣脱
地球引力的能力，就好象物体吸收了一种对抗万有引力的物质那样。“斥力子理论”把
普朗克能量子看作是一种对抗引力的实物粒子，称它为“斥力子”，并认为物体运动状
态的改变就是由于吸收或释放斥力子造成的。
在思维方法上，它有两个根本突破：其一,是把抽象的能量概念实物化，使能量有
一个实物载... 阅读全帖 |
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s*****r
发帖数: 11545 | 28 Scientists discover new form of light
DUBLIN, Ireland, May 17 (UPI) -- Researchers in Ireland have discovered a
new form of light. Their discovery is expected to reshape scientists'
understanding of light's basic nature.
Angular momentum describes the rotation of a light beam around its axis.
Until now, researchers believed the angular momentum was always a multiple
of Planck's constant -- a constant ratio that describes the relationship
between photon energy and frequency, and also sets the sca... 阅读全帖 |
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t**i
发帖数: 3 | 29 The Purdue University’s Quantum Foundations and Quantum Photonics
Laboratory (Prof. Tongcang Li’s group) has open positions for self-
motivated excellent postdocs, graduate students, visiting students and
visiting scholars starting from 08/2014.
Tongcang Li
Assistant Professor of Physics and Astronomy
Assistant Professor of Electrical and Computer Engineering
Purdue University
Email: t**[email protected]
http://www.physics.purdue.edu/people/faculty/tcli.shtml
Selected publications:
1. Peng Zhang, To... 阅读全帖 |
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t**i
发帖数: 3 | 30 The Purdue University’s Quantum Foundations and Quantum Photonics
Laboratory (Prof. Tongcang Li’s group) has open positions for self-
motivated excellent postdocs, graduate students, visiting students and
visiting scholars starting from 08/2014.
Tongcang Li
Assistant Professor of Physics and Astronomy
Assistant Professor of Electrical and Computer Engineering
Purdue University
Email: t**[email protected]
http://www.physics.purdue.edu/people/faculty/tcli.shtml
Selected publications:
1. Peng Zhang, To... 阅读全帖 |
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y**********9
发帖数: 566 | 31 来自主题: Immigration版 - 求两篇文章 我的邮箱是 [email protected]。 有包子送
1， Four-Photon Entanglement Generation with Integrated Optical Frequency
Combs
Christian Reimer, Michael Kues, Piotr Roztocki, Lucia Caspani, Yaron
Bromberg, Benjamin Wetzel, Brent E. Little, Sai T. Chu, David J. Moss, and
Roberto Morandotti
Integrated Photonics Research, Silicon and Nanophotonics 2016
Vancouver Canada
18–20 July 2016
ISBN: 978-1-943580-14-9
From the session
Quantum Photonic Circuits (IW3A)
==========================================... 阅读全帖 |
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e**n
发帖数: 5876 | 32 等效光圈和总通光量的关系, 要不你再读一遍?
或者这样吧, 给你举个简单的例子算一算:
LX7和RX100的转换关系不好算. 就用FF和43举个例子. 43的转换系数是2, 面积是FF的1
/4. 43的f2的等效光圈是f4. 假设单位时间内, 就说1/100s吧, 43用f2的光圈拍照,
整个sensor收集了1000个photon. 同样的单位时间内, 1/100s, FF用f2曝光, FF的面积
是43的4倍, FF整个sensor收集到了1000*4=4000个photon. FF用f4曝光, f4的光圈比f2
小2档, 也就是sensor上面单位面积的收集的photon是f2的1/4. 在1/100s, FF整个
sensor收集了1000个photon. 所以43在f2,等效光圈f4时和FF在f4的photon收集能力(
总通光量）一样. |
|
e**n
发帖数: 5876 | 33 我前面的帖子你没读?
"LX7和RX100的转换关系不好算. 就用FF和43举个例子. 43的转换系数是2, 面积是FF的
1
/4. 43的f2的等效光圈是f4. 假设单位时间内, 就说1/100s吧, 43用f2的光圈拍照,
整个sensor收集了1000个photon. 同样的单位时间内, 1/100s, FF用f2曝光, FF的面积
是43的4倍, FF整个sensor收集到了1000*4=4000个photon. FF用f4曝光, f4的光圈比f2
小2档, 也就是sensor上面单位面积的收集的photon是f2的1/4. 在1/100s, FF整个
sensor收集了1000个photon. 所以43在f2,等效光圈f4时和FF在f4的photon收集能力(
总通光量）一样." |
|
e**n
发帖数: 5876 | 34 "LX7和RX100的转换关系不好算. 就用FF和43举个例子. 43的转换系数是2, 面积是FF的
1
/4. 43的f2的等效光圈是f4. 假设单位时间内, 就说1/100s吧, 43用f2的光圈拍照,
整个sensor收集了1000个photon. 同样的单位时间内, 1/100s, FF用f2曝光, FF的面积
是43的4倍, FF整个sensor收集到了1000*4=4000个photon. FF用f4曝光, f4的光圈比f2
小2档, 也就是sensor上面单位面积的收集的photon是f2的1/4. 在1/100s, FF整个
sensor收集了1000个photon. 所以43在f2,等效光圈f4时和FF在f4的photon收集能力(
总通光量）一样."
那你再读一遍好不好. 这个等效光圈和总通光量的计算哪里错了? 怎么就"误导"了?
弱光的表现和光线充足的两种情况我昨天也分别解释了. |
|
e**n
发帖数: 5876 | 35 进光量一样画质一样, regardless of幅面面积. 前提条件(假设同样sensor工艺水平,
pixel well没有溢出,lens是同样素质)
这样说吧, 摄影就是一个采集photon的过程, 采集photon数量越多, SNR越高, 画质越
好. 那么怎么才能提高采集photon数量呢? 可以降低快门. 曝光时间长,采集的就多.
在同样曝光时间, 有2个方法. 第一, sensor面积越大,采集photon数量越多. 第二, 单
位面积光线强度越高(就是镜头光圈越大),采集photon数量越多. 所以, 要达到同样画
质, 一个方法是大sensor, 比如ff vs m43, 一个方法是大光圈, 比如f2 vs f4. 两个
方法等效.
不信的话, 你可以去dpr等网站看看对比图, 现在好像dpr也提供缩图对比了. 举个例子
, 比如m43的f2等效ff的f4, 那么在同样光圈和同样的快门速度下, ff的iso是m43的2倍
. 对不对? 这个时候m43和ff的total light一样. 你找一个ff的6400, 找一个m43的
1600, 对比一下, 你看看画质哪个好... 阅读全帖 |
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y*******o
发帖数: 746 | 36 物理系的Nature Photonics：
http://www.nature.com/nphoton/journal/vaop/ncurrent/abs/nphoton.2007.299.html
Nature Photonics
Published online: 3 February 2008 | doi:10.1038/nphoton.2007.299
Picosecond and low-power all-optical switching based on an organic photonic-
bandgap microcavity
Xiaoyong Hu1, Ping Jiang1, Chengyuan Ding1, Hong Yang1 & Qihuang Gong1
Abstract
Photonic crystals, materials with periodic dielectric structures, are able
to control the propagation states of photons owing to the so-calle |
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q**w
发帖数: 782 | 37 http://rmp.aps.org/accepted/R/90073E18W461210b80be18d6e6730d5cb
可能还是评不上院士
Multiphoton entanglement and interferometry
Jian- Wei Pan, Zeng- Bing Chen, Chao- Yang Liu, Harald Weinfurter, Anton
Zeilinger, and Marek Zukowski
Accepted Tuesday Sep 20, 2011
Multi-photon interference reveals strictly non-classical phenomena. Its
applications range from fundamental tests of quantum mechanics to photonic
quantum information processing, where a significant fraction of key
experiments achieved so far comes ... 阅读全帖 |
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v*******e
发帖数: 11604 | 38 这篇文章：
www.quantenkryptographie.at/ECOCPoppe_2005.pdf
的图二标出了一些能够entangled和不能entangled的光子对；他说：
“If the polarization of one photon is strictly linked to another property
of a photon, entanglement is not possible. The photons indicated by the
rectangular position in fig. 2 have different wavelengths and are
distinguishable. Even when both pair-photons are degenerated, i.e. having
the same wavelength, but different emission angles, the polarization is
determined by the position. Only for the intersec... 阅读全帖 |
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t**i
发帖数: 3 | 39 The Purdue University’s Quantum Foundations and Quantum Photonics
Laboratory (Prof. Tongcang Li’s group) has open positions for self-
motivated excellent postdocs, graduate students, visiting students and
visiting scholars starting from 08/2014.
Tongcang Li
Assistant Professor of Physics and Astronomy
Assistant Professor of Electrical and Computer Engineering
Purdue University
Email: t**[email protected]
http://www.physics.purdue.edu/people/faculty/tcli.shtml
Selected publications:
1. Peng Zhang, To... 阅读全帖 |
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b*****d
发帖数: 271 | 40 现在的粒子物理理论把除了引力之外基本相互作用都放到一个framework里，
现在的难题是如何量子化引力。 这些工作的发展，这些年受到实验技术的限制，目前
只有LHC， 能标只能达到14 TeV ( ~1.4 * 10^4 GeV ) ，而引力对应的普朗克能标则
是10^19 GeV。在相当长的一段时间内， 大统理论得不到实验的支持。
但在其他理论，也有很多发展，特别是宇宙学。
近些年来的热点就是暗物质，科普一下最近的实验吧，
背景：pamela测到宇宙中GeV的正电子反常(arXiv:0810.4995)， 作为反物质， 密度应
该随着能量的增加而下降， 但是目前实验测到正电子的密度在GeV附近有反弹(图见Fig
4 of arXiv:0810.4995)。目前流行的观点是， GeV的暗物质湮灭产生正电子，所以
GeV能标附近正电子密度增加。
1) 现在大家都去galaxy中心找暗物质湮灭产生的gamma射线， Rouven提议去dwarf
galaxies里去找gamma射线(arXiv:0902.4750)。point是dwarf galaxies不发光， 背景
很小，实验上好测... 阅读全帖 |
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b***y
发帖数: 14281 | 41 既然有人争论方的学术水平，就上网搜了一下。应该说这个水平对于一个junior
faculty来说可以算是很牛B了，但是对于老方这种senior的已经搞了一辈子的人来说，
就只能算so so。不要说是院士，离aps fellow的级别也还差了不少。引用率最高的一
篇文章还是95年到了arizona之后跟老外合作的，被引118次，这也是方唯一一篇被引用
上百次的文章。可见方励之89之前确实没有做出过什么重要的工作，他的名声和地位绝
对是靠政治得来的，当然其中部分的也是80年在中国搞科普所得，必须承认科普工作也是
有重要的社会意义的。
(BTW，有人说你这个搜索未必完整。不错，确实不能保证100％毫无遗漏。但是我
用的search engine is THE search engine everybody in this community uses today.
So, if any article is not found by this search engine, sadly, it simply doesn't matter,
because no one would ever n... 阅读全帖 |
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发帖数: 1 | 42 Lieber's contributions to the rational growth, characterization, and
applications of a range of functional nanoscale materials and
heterostructures have provided concepts central to the bottom-up paradigm of
nanoscience. These include rational synthesis of functional nanowire
building blocks, characterization of these materials, and demonstration of
their application in areas ranging from electronics, computing, photonics,
and energy science to biology and medicine.[13]
Nanomaterials synthesis. ... 阅读全帖 |
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L***s
发帖数: 9258 | 43 Singapore-MIT Alliance for Research and Technology Centre
SMART is a major research enterprise established by the Massachusetts
Institute of Technology (MIT) in partnership with the National Research
Foundation of Singapore (NRF). SMART serves as an intellectual hub for
international research collaborations, not only between MIT and Singapore,
but also involving researchers from the region and beyond. At SMART, we
identify and carry out research on critical problems of societal importance.
SM... 阅读全帖 |
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L***s
发帖数: 9258 | 44 Singapore-MIT Alliance for Research and Technology Centre
SMART is a major research enterprise established by the Massachusetts
Institute of Technology (MIT) in partnership with the National Research
Foundation of Singapore (NRF). SMART serves as an intellectual hub for
international research collaborations, not only between MIT and Singapore,
but also involving researchers from the region and beyond. At SMART, we
identify and carry out research on critical problems of societal importance.
SM... 阅读全帖 |
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L***s
发帖数: 9258 | 45 SMART is a major research enterprise established by the Massachusetts
Institute of Technology (MIT) in partnership with the National Research
Foundation of Singapore (NRF). SMART serves as an intellectual hub for
international research collaborations, not only between MIT and Singapore,
but also involving researchers from the region and beyond. At SMART, we
identify and carry out research on critical problems of societal importance.
SMART is a magnet attracting and anchoring global research t... 阅读全帖 |
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e**n
发帖数: 5876 | 46 你测试相机在大白天base iso测嘛? 大家多花了那么多钱上了FF, 是因为大白天base
iso画质比APS好吗? 不过, 我还是在原文进行了补充了一下废话. copy在下面了
"
比较光线充足的条件下的base iso的画质是一件很无聊的事情. 在光学充足的时候,
现在的芯片技术可以做到FF和APS在同样base iso时成像画质差别不大. RX100和其他DC
芯片大小的比例关系大致相对于FF和APS的关系. 再考虑到LX7 的base iso是 80,
RX100是125, 在同样面积, 光学充足的情况下, LX7能容纳比RX100多60%左右的photon.
RX100的面积比LX7大个160%左右, 那么photon saturation总量RX100只比LX7多60%左
右. photon总量决定画质. 这个photon总量的差别比FF和APS还要小. 差不多是APS和43
的比例关系. 现在的芯片技术可以做到APS和43在同样base iso时成像画质几乎一样.
例子就是EM5和NEX, 而且EM5实际base iso比nex的还要高一点. LX7和RX10... 阅读全帖 |
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e**n
发帖数: 5876 | 47 不客气. 但kyro把这个帖子马克了, 你非要overrule了kyro, 把它un马克了. 总得有
overwhelming的理由吧. 那我和你探讨探讨这些理由总可以吧?
你前面给的un马克理由
"等效光圈用来讨论进光量是错的"
这个我相信已经解释清楚了吧?
下面你又说
"等效光圈->进光量->画质
这每一步都不对"
那么就讨论"进光量->画质"的关系吧. 我举的例子, "每个像素photon数一样，SNR也一
样", 这里有个前提, 就说感光器等技术相似, photon最后变成像素里面的颜色, 要经
过很多处理, 从sensor的具体结构, filter, 到相机内的处理器, converter, 到软件
的解raw算法. 到处都是variable. 但photon数量决定SNR是基本的. 这也是感光器等
技术相似的前提下, photon数量是成像的基本. 而等效光圈和总通光量方便了各个画幅
大小之间的横向比较. 这也就是我的帖子的主旨. 你要是觉得"有不少错误之处", 我
希望你能指出来, 我闻过则喜. |
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t******s
发帖数: 43 | 48 Ph.D. Student
We are recruiting highly motivated students with strong research interests
to pursue Ph.D. degree in the areas of nano-photonics, plasmonics and
metamaterials, starting from Spring 2012 or Fall 2012. Our interdisciplinary
research projects require students having strong experimental or
theoretical skills in one of the following areas: electromagnetics, optics
and photonics, thermo-fluids and heat transfer, applied physics, NEMS/MEMS,
and cleanroom nanofabrication. Students with var... 阅读全帖 |
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y********d
发帖数: 150 | 49 Ph.D. Student
We are recruiting highly motivated students with strong research interests
to pursue Ph.D. degree in the areas of nano-photonics, plasmonics and
metamaterials, starting from Fall 2012. Our interdisciplinary research
projects require students having strong experimental or theoretical skills
in one of the following areas: electromagnetics, optics and photonics,
thermo-fluids and heat transfer, applied physics, NEMS/MEMS, and cleanroom
nanofabrication. Students with various background... 阅读全帖 |
|
y********d
发帖数: 150 | 50 Ph.D. Student
We are recruiting highly motivated students with strong research interests
to pursue Ph.D. degree in the areas of nano-photonics, plasmonics and
metamaterials, starting from Fall 2012. Our interdisciplinary research
projects require students having strong experimental or theoretical skills
in one of the following areas: electromagnetics, optics and photonics,
thermo-fluids and heat transfer, applied physics, NEMS/MEMS, and cleanroom
nanofabrication. Students with various background... 阅读全帖 |
|
