经济学人265:传递热量 良好的传导

 　　Science and technology

　　科学技术

　　Channelling heat

　　传递热量

　　Good conduct

　　良好的传导

　　It may soon be possible to control heat flows with great precision

　　有可能实现对热流的精确控制

　　HEAT, as every schoolboy knows, moves in three ways: conduction, convection and radiation.

　　每个学生都知道热传递有三种方式：传导、对流和辐射。

　　Convection is the mass movement of a fluid: hot water rising, for example.

　　对流是液体的整体移动，比如热水上升。

　　Radiation is simply infra-red light.

　　辐射只是红外光线。

　　Engineers know how to control both of these reasonably well.

　　工程师知道怎样合理地控制这两种热传递方式。

　　Conduction, however, is most similar to the transmission of sound.

　　传导很像声音传播。

　　It is caused, in other words, by atoms vibrating and passing such vibrations¹ on to their neighbours.

　　换言之，原子震动引起传导，这种震动向邻近物体传播。

　　Until now, controlling the conduction of heat through solid objects has been a tricky² engineering challenge.

　　时至今日，控制热量通过固体传导对工程界还是一个棘手的挑战。

　　But, by making the analogy with sound explicit³, Martin Maldovan, an engineer at the Massachusetts Institute of Technology, thinks he may have found a way of doing so.

　　然而麻省理工学院的工程师Martin Maldovan认为自己找到了解决问题的方法，可以使热传导以类似声波传递的方式进行。

　　Dr Maldovan's invention, published in Physical Review Letters, is based on the idea of a sonic filter.

　　物理评论快报刊登了Maldovan博士的发明，这个发明基于声音过滤器的理念。

　　A good way to filter sound—to eliminate certain frequencies while allowing others through—is to transmit the sound waves through a crystal.

　　这是一个过滤声音的好办法，就是通过水晶传递声波—在消除特定频率的同时允许其他频率通过。

　　The size of the gaps between the crystal's atoms will govern which frequencies can pass.

　　水晶原子之间缝隙的大小决定了哪种频率的声波可以通过。

　　Moreover, the path the sound takes can be controlled by introducing deliberate flaws into the crystal's atomic lattice.

　　此外，可以在水晶的原子点阵之间故意制造裂纹来控制声音的传播路径。

　　These flaws act as waveguides, channelling the sound energy along themselves.

　　这些裂纹起到了波导的作用，声能在裂纹之间传递。

　　One difference between sound and heat is that most sound waves have low frequencies, vibrating only a few thousand times a second, whereas most heatwaves have high frequencies, vibrating trillions of times a second.

　　声音传递和热量传递之间的一个区别在于声波的频率低，每秒只震动几千次，而大部分热波的频率很高，每秒震动数万亿次。

　　In general, low frequencies propagate farther than high ones.

　　通常低频率比高频率传播的更远。

　　This is why previous researchers had a difficult time trying to send heat through crystal lattices.

　　这就是以前的研究者试图在水晶点阵之间传播热能时遇到困难的原因。

　　Dr Maldovan, however, realised that although most heat is high-frequency, some has frequencies that approach those of sound.

　　然而Maldovan博士认识到尽管很多热波的频率很高，然而有些热波的频率接近声波频率。

　　He theorised that if the highest-frequency waves were stripped away, it might be possible to control the remainder.

　　他的理论是如果把频率最高的热波去掉，其余的热波就有可能得到控制。

　　To test this idea, he grew crystals of silicon⁴ that contained tiny particles of germanium in their lattices.

　　为了验证这个观点，他研制出了硅晶体，晶体的点阵之间含着细小的锗颗粒。

　　The layouts of these crystals scattered⁵ and blocked high-frequency heatwaves but allowed low-frequency waves through.

　　散乱的晶体的布局阻挡了高频率的热波，却允许低频率的热波通过。

　　These remaining waves had frequencies in a range of 100 billion to 300 billion vibrations a second.

　　这些可以通过晶体的热波的频率范围在每秒震动一千亿次到每秒震动三千亿次之间。

　　They were still heatwaves and carried warmth, but because their frequencies were lower they behaved much more like sound.

　　他们依然是热波而且带着热量，但是这些热波的频率比较低，所以它们的传导方式和声音的传播方式就很像了。

　　And Dr Maldovan could control the heat's path in waveguides as tightly as that of sound waves.

　　博士Maldovan可以在波导上控制热波的传导途径，使热波传导和声波传导一样紧密。

　　Though turning these crystals into practical products will require further tinkering, Dr Maldovan thinks they will be immediately useful in the construction of thermoelectric materials, which transform waste heat into electricity, and will ultimately lead to the thermal⁶ equivalent of diodes, allowing heat circuits analogous⁷ to electrical ones to be built.

　　尽管把这类晶体转化成实用产品还需要进一步的思考，Maldovan博士认为这类晶体可以马上投入到热电材料的制作上，将废热转化为电能，最后通向热当量的二极管，可以建立和电路类似的热路。

　　Where that would lead, no one knows.

　　谁也不知道热路的那一端联着什么。

　　But it is worth bearing in mind that it was the ability to control convective heat, via the steam engine, which powered the industrial revolution.

　　但是控制对流热流还是值得我们思考的，因为蒸汽机给工业革命提供了能量。

　　Controlling conductive heat might have equally unforeseen consequences.

　　同样，控制传导热流也会带来意想不到的结果。

　　1.heat flow 热流，热流动

　　As soon as I start reiki I usually feel a heat flow from the palm of my hands.

　　当我开始灵疗的时候，我总能感到一股热量在我的手掌处流动。

　　Practical application for heat flow measurements in ocean floors are the location of hot brines.

　　洋底热流量测量的实际目的是圈定热卤水的位置。

　　2.similar to 类似得，同样的；如同

　　You should see something similar to figure 2.

　　你应该会看到类似图2的内容。

　　Try and visualize⁸ this energy as a bright white light similar to that of sunlight.

　　试着想象这一能源，把它当做一种明亮如阳光一样的白光。

　　3.base on 使建立在…基础上

　　Lance cpl. baker⁹ at shir ghazay patrol base on jan. 30.

　　兰斯科普尔贝克在西尔嘎泽巡逻基地。

　　But this is a worryingly flimsy base on which to build a bigger economic and monetary¹⁰ union.

　　但是在经不起风吹雨打的基础上就想建立一个较为庞大的经济和货币联盟实在是令人忧心如焚。

　　4.in general 通常；大体上；一般而言

　　That's a good rule for life in general.

　　一般来说这是一个很好原则。

　　Three explanations apply in general, however.

　　然而，这种现象通常有三种解释。

1 vibrations   

n.摆动( vibration的名词复数 )；震动；感受；（偏离平衡位置的）一次性往复振动

参考例句：

• We could feel the vibrations from the trucks passing outside. 我们可以感到外面卡车经过时的颤动。
• I am drawn to that girl; I get good vibrations from her. 我被那女孩吸引住了，她使我产生良好的感觉。 来自《简明英汉词典》

2 tricky   

adj.狡猾的，奸诈的；(工作等)棘手的，微妙的

参考例句：

• I'm in a rather tricky position.Can you help me out?我的处境很棘手，你能帮我吗？
• He avoided this tricky question and talked in generalities.他回避了这个非常微妙的问题，只做了个笼统的表述。

3 explicit   

adj.详述的，明确的；坦率的；显然的

参考例句：

• She was quite explicit about why she left.她对自己离去的原因直言不讳。
• He avoids the explicit answer to us.他避免给我们明确的回答。

4 silicon   

n.硅(旧名矽)

参考例句：

• This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
• A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。

5 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

6 thermal   

adj.热的，由热造成的；保暖的

参考例句：

• They will build another thermal power station.他们要另外建一座热能发电站。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

7 analogous   

adj.相似的；类似的

参考例句：

• The two situations are roughly analogous.两种情況大致相似。
• The company is in a position closely analogous to that of its main rival.该公司与主要竞争对手的处境极为相似。

8 visualize   

vt.使看得见，使具体化，想象，设想

参考例句：

• I remember meeting the man before but I can't visualize him.我记得以前见过那个人，但他的样子我想不起来了。
• She couldn't visualize flying through space.她无法想像在太空中飞行的景象。

9 baker   

n.面包师

参考例句：

• The baker bakes his bread in the bakery.面包师在面包房内烤面包。
• The baker frosted the cake with a mixture of sugar and whites of eggs.面包师在蛋糕上撒了一层白糖和蛋清的混合料。

10 monetary   

adj.货币的，钱的；通货的；金融的；财政的

参考例句：

• The monetary system of some countries used to be based on gold.过去有些国家的货币制度是金本位制的。
• Education in the wilderness is not a matter of monetary means.荒凉地区的教育不是钱财问题。