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发表于 2011-12-22 17:32:42
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日志：
2011/12/22，refla
初稿。
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前言
又找到一篇文章，进一步讲解了“量子捕获”的原理 —— 只有分子级厚度的超导层，如果某一点的分子结构存在缺陷，就会被磁通量贯穿。
需要提醒大家注意的是，本文并非官方权威发布，而是一名老外的博客文章，后被转载到 io9.com 这个科普网站上的。我觉得他讲得还是很有道理的，所以分享给大家，仅作参考之用。
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原文：http://io9.com/superconductivity/
Quantum locking will blow your mind — but how does it work?
让你意淫的量子锁定是如何工作的？
If case you haven't seen it yet, here's the quantum levitation (or, more accurately, quantum locking) video that's taken the internet by storm in the last 36 hours.
如果你还没有见识过它，就先看看量子悬浮（确切地说，是量子锁定）视频吧！在过去 36 小时里，它刮起了一场互联网风暴。
And while quantum locking (also known as "flux pinning") may not have anything to do with Weeping Angels, it's still pretty freaking amazing. But how does it work, and where the hell is your hoverboard?
虽然量子锁定（也称“磁通极点”）与哭泣天使【译注1】无关，但它还是非常非常地惊人。它是如何实现的？这个悬浮板（hoverboard）到底是怎么回事？
译注1：在科幻剧《神秘博士》第3季中提到，哭泣天使（The weeping Angels）是一种专门偷时间的外星生物，他们是量子锁定的。
参见http://baike.baidu.com/view/3247041.htm
Fortunately for all of us, Joe Hanson—who runs the awesome blog It's Okay to be Smart went out of his way to explain this phenomenon in more accessible terms:
幸运的是，乔·汉森在他那一级棒的博客 It's Okay To Be Smart 中，使出浑身解数，试图用较为通俗易懂的语言来解释这一现象。
What you start with is an inert [i.e. chemically inactive] disc, in this case a crystal sapphire wafer. That wafer is then coated with a superconductor called yttrium barium copper oxide. When superconductors get very cold (like liquid nitrogen cold) they conduct electricity with no loss of energy, which normal conducting materials like copper can't do.
我们的故事开始于一张惰性（即化学性质不活泼）盘，一片水晶蓝宝石晶圆被名为钇钡铜氧化物的超导体包裹着。超导体在液氮低温下导电时，不存在能量损耗，这是一般的导电材料（比如铜）所做不到的。
Superconductors hate magnetic fields (when cold enough), and normally would just repel the magnetic force and float in a wobbly fashion. But because the superconductor is so thin in this case, tiny imperfections allow some magnetic forces through. These little magnetic channels are called flux tubes [pictured here].
超导体会排斥磁场，因而产生反向磁力使磁铁以抖动的方式悬浮起来。但本例中的超导体是如此的薄，以至于有些很小很小的点被磁通量穿透，形成被称为“磁通量管道”的磁通量通道。
磁通量管道
The flux tubes cause the magnetic field to be "locked" in all three dimensions, which is why the disk remains in whatever position it starts in, levitating around the magnets.
磁通管道导致磁场在三个维度方向上，都被“锁定”。这就是盘片能保持住它原始姿势，绕着磁铁悬浮移动的原因。
Those of you with backgrounds in materials science, ceramics engineering or graduate-level physics may recognize this phenomenon as something similar to the Meissner-Ochsenfeld effect, though strictly speaking what you're witnessing is not a result of the Meissner effect.
如果你有材料科学方面的背景，熟知陶瓷工程或者你的物理学达到研究生水平，就能看出这一现象类似于迈斯纳-奥克森费尔德效应【译注2】。
译注2：迈斯纳-奥克森费尔德效应就是我们常说的“迈斯纳效应”。
参见：http://baike.baidu.com/view/59063.htm
In the Meissner effect, the superconductor that is placed within the magnetic field deflects the field entirely (see the image pictured here), such that none of the field passes through the object itself.
在迈斯纳效应中，磁场中的超导体会把全部磁通量排出体外。换句话说，也就是没有磁通量能穿过超导体。
右图是物质变成超导体后的磁力线走向
But as Hanson points out, the thinness of the superconductive coating featured in the quantum locking video allows for the magnetic field to penetrate it (albeit in discrete quantities) wherever there exist defects in the superconductor's molecular structure. This penetration gives rise to the "flux tubes" (again, pictured alongside Hanson's explanation), which pass through the inert crystal sapphire wafer and "trap" it in midair. This trapping provides the typically wobbly "levitation" characteristic of the Meissner effect a stiffer quality.
但正如汉森指出的那样，在《量子锁定》视频中，薄薄的超导覆盖层被磁场击穿了（尽管只是些散布着的点），超导层在这些点的分子结构存在缺陷。如果这样的超导体悬浮在磁场中，这些有缺陷的点就会“俘获”磁通量，并贯穿化学性质不活泼的水晶蓝宝石晶圆，从而形成所谓的“磁通量管道”。这一捕获实现了迈斯纳效应 —— 典型地磁悬浮特性。
As for your hoverboard: as Hanson points out in his explanation, superconductors only possess their field-banishing properties at extremely cold temperatures, making hovering skateboards more or less impossible at this point. But for what it's worth, there's currently no evidence that says room-temperature superconductors can't exist—we just haven't haven't discovered them yet.
至于悬浮板（hoverboard）：一如汉森在他的博客所说，超导体在极低温下只具有抗磁性，这使得悬浮板或多或少地漂移滑动，不可能固定在一点上。这个有什么用呢？目前没有任何证据证明室温超导体不能存在，我们只是还没有找到它们而已。 |
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发表于 2011-12-20 15:45:12
发表于 2011-12-20 18:03:39
