星期六, 三月 31, 2007

量子彩票是你最好的赌注

量子彩票是你最好的赌注

是不是每次滚出来的球都不是你持有的彩票的号码?那么,何不来玩玩由一名英国大学生发明的游戏――赌辐射衰减周期的量子彩票?

Quantum lottery is your best bet (Mar 28)
http://physicsweb.org/article/news/11/3/20
Convinced the balls are always against you when you play the lottery?
Then why not bet on radioactive decay in the "quantum lottery", a game
invented by a university student in the UK.

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星期三, 三月 28, 2007

偶极子激光器工作温度首次降至室温

偶极子激光器工作温度首次降至室温

英国和瑞士物理学家首次将偶极子激光器的工作温度降至室温。研究人员宣称,这种半导体激光器件所需要的能量仅为类似的传统固态激光器的十分之一。该技术突破可为光存储系统(CD, DVD, etc.)提供极低功率消耗的激光器。

Polariton laser reaches room temperature (Mar 27)
http://physicsweb.org/article/news/11/3/19
The first polariton laser to operate at room temperature has been
demonstrated by physicists in the UK and Switzerland. The researchers
claim that the semiconductor device requires ten times less energy to
operate than a comparable conventional solid-state laser. The
breakthrough could lead the way to very low power lasers for use in
optical data-storage systems (Phys. Rev. Lett. 98 126405).

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星期二, 三月 27, 2007

对牛顿定律进行终极检验的实验

对牛顿定律进行终极检验的实验

奥地利的一名物理学家最近提出了一个实验,有可能揭示牛顿万有引力定律的一个缺陷。如果该缺陷确实存在,那么解释银河系的运动就不需要被迫引入暗物质了。

Experiment sets the ultimate test for Newton's laws (Mar 16)
http://physicsweb.org/article/news/11/3/12
A physicist in Australia has come up with an experiment that could
potentially reveal a flaw in Newton's law of gravitation. If the flaw
exists, it would be the first evidence in support of theories that
explain the movement of galaxies without having to introduce "dark
matter" (Phys. Rev. Lett. 98 101101).

双负性媒质的频率范围已经接近可见光波段了

美国研究人员最近制作的一种材料,在波长为813纳米的红外光波段,其导磁率和介电率都为负值。这是目前为止能实现双负性的材料所达到的最短波长,并且已经与可见光谱380-780纳米非常接近。之前的纪录为1500纳米。这个结果朝着实现可见光波段双负性材料(DN-NIMs)的目标前进了一大步。

Double-negative metamaterial edges towards the visible (Mar 16)
http://physicsweb.org/article/news/11/3/13
Researchers in the US have created a metamaterial that has a negative
magnetic permeability and negative electric permittivity for infrared
light with a wavelength of 813 nm. This is claimed to be the shortest
wavelength yet for such a metamaterial and lies just outside of the
visible spectrum at 380-780 nm. The previous record had been about 1500
nm, and the result is an important step towards the creation of
double-negative negative-index metamaterials (DN-NIMs) that operate in
the visible range.

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星期日, 三月 25, 2007

用探针来寻找精细结构常量的变化

用探针来寻找精细结构常量的变化

美国宇宙学家计划用一种新的方法来测量130亿年前的精细结构常量,以了解该常量的值是否与现在不同。该方法通过测量氢原子如何吸收宇宙微波背景辐射光子来获得精细结构常量的值,虽然还有待天文观察的验证。精细结构常量决定了电磁相互作用的强度,是自然界里的一个基本常量,这个方法有可能提供新的证据证明该常量实际上并不一定保持恒定。

Probe seeks changes in fine-structure constant (Mar 23)
http://physicsweb.org/article/news/11/3/18
Cosmologists in the US have proposed a new way to measure the
fine-structure constant as it was some 13 billion years ago -- and see
if its value differed from that measured today. The method, which has
yet to be verified using astronomical observations, involves measuring
how hydrogen atoms absorbed photons from the cosmic microwave
background. It could provide further evidence that this fundamental
constant of nature -- which defines the strength of the electromagnetic
interaction -- is not actually a constant after all (Phys. Rev. Lett. 98
11301).

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星期五, 三月 23, 2007

物理学家们在纳米尺度下对光进行控制

物理学家们在纳米尺度下对光进行控制

欧洲的物理学家们揭示了一种可以在远小于激光波长的尺度下对激光的光强分布进行调控的技术。这种技术结合了脉冲成形和近场光学等手段。研究人员认为,这是将激光作为微小尺度下操作物质的工具这一研发进程中一个巨大的进步。

Physicists control light at the nanoscale (Mar 22)
http://physicsweb.org/article/news/11/3/15
Physicists in Europe have unveiled a new technique that can control the
intensity distribution of laser pulses at dimensions that are much
smaller than the wavelength of the laser light. The method combines
pulse-shaping techniques with near-field optics and the researchers
claim that it is a major step forward in the development of laser-based
tools for the manipulation of matter on a very small length scales
(Nature 446 301).

自旋需要长时间来逐渐变慢

美国工程师们发现,在有机纳米导线构成的"自旋阀"中,电子自旋极其稳健。弗吉尼亚联邦大学和西西纳提大学的研究团队发现,这些导线中的电子自旋耗散时间起码比其它任何一个系统中的电子自旋耗散时间长1000倍。该结果意味着这些材料可能是用于自旋电子学――一种在电子线路、计算机或者其他装置里利用电子自旋来对信息进行编码的新兴研究领域――的理想选择。

Spins take their time to relax (Mar 22)
http://physicsweb.org/article/news/11/3/16
Engineers in the US have discovered that the spin of electrons in
organic nanowire "spin valves" is extremely robust. A team of
researchers from Virginia Commonwealth University and the University of
Cincinnati have found that the "spin-relaxation time" in these wires is
at least 1000 times longer than that reported in any other system. The
result means that these materials could be ideal for use in spintronics,
an emerging field that exploits the spin of the electron to encode
information in electronic circuits, computers and other devices (Nature
Nanotechnology doi:10.1038/nnano.2007.64).

超级放大镜头让人看到从未见过的细节

美国的两个物理学家团队独立地创造出了第一台使用具有负折射系数的元材料的真正超级放大镜头。与传统镜头不同的是,超级镜头可以提供几乎无限分辨率的图像。这样,也许在某一天,能够通过它来实现蛋白质、病毒、DNA等的光学成像。

Magnifying superlenses show more detail than ever before (Mar 22)
http://physicsweb.org/article/news/11/3/17
Two teams of physicists from the US have independently created the first
truly magnifying "superlenses" using metamaterials with a negative index
of refraction. Unlike conventional lenses, superlenses can provide
images of almost limitless resolution, and could one day enable the
optical imaging of proteins, viruses and DNA.

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星期三, 三月 21, 2007

医用扫描器已经能够控制细胞大小的医疗仪器了

医用扫描器已经能够控制细胞大小的医疗仪器了

加拿大的科学家们应用一种传统的核磁共振成像(MRI)系统来控制血管里微小的金属珠的移动。这个实验对MRI最终用于控制微小"无法拴住"的器件来进行完全非侵入式的外科手术起到了示范性的作用。

Hospital scanners could control cell-sized medical devices (Mar 20)
http://physicsweb.org/article/news/11/3/14
Physicists in Canada have used a conventional magnetic resonance imaging
(MRI) system to control the movement of a small metal bead inside blood
vessels. The experiment demonstrates that MRI systems could eventually
control tiny "untethered" devices that perform truly non-invasive
surgery (App. Phys. Lett. 90 114105).

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星期一, 三月 19, 2007

FT中文网对读者评论进行观点一致性审核

ftchinese经常对中国政府的互联网审核制度发表不满,但ft中文网的读者留言审查制度却也不亚于中国政府。

ftchinese,只允许符合你们意图的留言才能被审核通过,搞得跟共产党一样狠。

之前我对凯雷收购徐工的评论不符合FT中文网“要求中国放宽对外资限制”的意图,并表示之前的福建南孚被外国资本玩弄最终在愚蠢官员的利益驱动配合下丧失,导致优质的国有资产被贱卖给外国资本。而徐工收购案恐怕也会是另一个(但不会是最后一个)南孚。

这样的留言没有通过ft中文网的审核,但这却是一个ftchinese读者实实在在的评论。

作一个让人尊敬、并且值得信赖的媒体,允许读者发表不同意见,这是基本素质。

凭什么中国就该把所有的优质资产都向外国人敞开?美国还不让中国收购一个只排名第七的石油公司呢,收购IBM PC的时候,也是费尽周折。

搞笑的ft中文网。

星期日, 三月 18, 2007

只能同时给一个电子制冷的电冰箱

只能同时给一个电子制冷的电冰箱

芬兰和意大利的物理学家们正计划建造一种可以将物体冷却到10mK的微型电冰箱。这个已经部分建成的装置,通过允许单独的热电子从金属岛由隧道效应穿过一个绝热的缝隙而到达处于超导状态下的铅上。赫尔辛基技术大学的Jukka Pekola指出,这个装置有比传统隧道节点电冰箱效率高3倍多的潜力,并且,传统的隧道节点电冰箱仅能冷却至100mK。

Refrigerator cools one electron at a time (Jan 24)
http://physicsweb.org/article/news/11/1/20
Physicists in Finland and Italy have unveiled plans for a tiny
refrigerator that might be able to cool objects to temperatures as low
as 10 mK. The device, which has been partially built, works by allowing
single "hot" electrons to tunnel through an insulating gap from a metal
island to a superconducting lead. According to Jukka Pekola of the
Helsinki University of Technology, the device has the potential to be
about three times more efficient than conventional tunnel-junction
refrigerators, which struggle to cool below about 100 mK (Phys. Rev.
Lett. 98 037201).

Hanbury Brown螺旋效应的一种新螺旋体

相互排斥的波色-爱因斯坦和费米-迪拉克统计学首次同时在相同的仪器上发现。荷兰和法国的物理学家宣告了这一消息,他们对两种氦同位素原子的Hanbury Brown 螺旋效应进行了研究。这个发现可能使量子相关性的直接观测成为可能。

Another new twist on the Hanbury Brown-Twiss effect (Jan 24)
http://physicsweb.org/article/news/11/1/21
Bose-Einstein and Fermi-Dirac statistics, which are by definition
mutually exclusive, have been witnessed in the same apparatus for the
first time. This is the claim of physicists in the Netherlands and
France, who investigated the atomic "Hanbury Brown-Twiss effect" for two
isotopes of helium. The discovery could make direct observations of
quantum correlations possible (Nature 445 402).

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