Carbon Nanotubes托福听力原文翻译及问题答案

Carbon Nanotubes托福听力原文翻译及问题答案

一、Carbon Nanotubes托福听力原文：

NARRATOR:Listen to part of a lecture in a structural engineering class.MALE PROFESSOR:Today,let's begin to look at structural engineering in the Space Age.Uh,new problems...new possibilities mean we can think in new ways...find radically different approaches.So let's consider,uh—well,What would you say is the biggest obstacle today to putting structures,equipment,people uh—anything,really—into space?FEMALE STUDENT:Well,the cost,right?MALE PROFESSOR:Exactly.I mean,just taking the space shuttle up and back one time is hugely expensive.Uh,why?FEMALE STUDENT:I-I guess a lot of it is for fuel,right?To—to get the rocket going fast enough...MALE PROFESSOR:OK...Fast enough to...?FEMALE STUDENT:To,uh,escape Earth's gravity.MALE PROFESSOR:Good.So we are burning up an enormous amount of fuel at every launch,just to get the rocket up to what's known as"escape velocity".Now,escape velocity is around 11 kilometers a second,pretty fast.But do we really have to go this fast?FEMALE STUDENT:Well...yeah!I mean,how else can you,um,escape?I mean,that's the whole point of escape velocity,right?Otherwise gravity will pull you back down to the Earth....

MALE PROFESSOR:Actually,that's a common misconception.Escape velocity is simply the speed of an object that's,uh,let's say,shot out of a cannon,the minimum initial speed so that the object could later escape Earth's gravity on its own.But that's just if there's no additional force being applied.If you keep on supplying force to the object,keep on pushing it upward.It could pull away from Earth's gravity at any speed.FEMALE STUDENT:Even really slow?So you're saying,like,if you had a ladder tall enough,you could just climb into space?MALE PROFESSOR:Yeah—uh,well,theoretically.I mean,I can see some practical problems with the ladder example.Uh,like you might get just a little bit tired out after the first few thousand kilometers or so,uh,especially with all the oxygen tanks you'd have to be hauling up with you!MALE PROFESSOR:No.I was thinking more along the lines of an elevator...FEMALE STUDENT:Wait,you're serious?MALE PROFESSOR:Sure.An elevator.That's a new idea to most of us,but in fact it's been around for over a century.If we could power such an elevator with solar energy,we could simply rise up into space--for a fraction of the cost of a trip by rocket or shuttle.FEMALE STUDENT:But wait,elevators don't just rise up.They have to hang on some kind of wire or track or something.MALE PROFESSOR:Uh,true—and for decades that's exactly what's prevented the idea from being feasible,or even just taken seriously: Um,where do we find a material strong enough,yet light weight enough,to act as a cable or track. I mean,we're talking 36,000 kilometers here—and the strain on the cable would be more than most materials could bear.

But a new material developed recently has a tensile strength higher than diamond,yet it's much more flexible. I'm talking about carbon nanotubes.

FEMALE STUDENT:OK.I've read something about carbon nanotubes.They are strong,alright,but aren't they just very short little cylinders in shape?MALE PROFESSOR:Ah,yes.But these cylinders cling together at a molecular level.You pull out one nanotube or row of nanotubes,and its neighbor's come with it,and their neighbors,and so on.So you could actually draw out a 36,000-kilometer strand or ribbon of nanotubes stronger than steel,but maybe a thousandth the thickness of a human hair.FEMALE STUDENT:OK.Fine.But what's going to hold this ribbon up and keep it reach enough to support an elevator car?MALE PROFESSOR:Well,we definitely have to anchor it at both ends.So what we need is a really tall tower here on the ground right at the equator and a satellite in geostationary orbit around the Earth.There's a reason I mentioned that figure of 36,000 kilometers.That's about how high an object would have to be orbiting straight up from the equator to constantly remain directly above the exact same spot on the rotating planet Earth.So once you are in this geostationary orbit right over the tower,just lower your carbon nanotube cable down from the satellite,tether it to the tower here on Earth.And there you have it!FEMALE STUDENT:So you really think this is a possibility?Like,how soon could it happen?MALE PROFESSOR:Well,the science fiction writer Arthur C.Clarke talked about building a space elevator back in the 1970s.And when someone asked him when he thought this idea might become a reality,his reply was,"Probably about fifty years after everybody quits laughing."

二、Carbon Nanotubes托福听力中文翻译：

旁白：请听结构工程课的一部分讲座。男教授：今天，让我们来看看太空时代的结构工程。嗯，新的问题…新的可能性意味着我们可以用新的方式思考…找到完全不同的方法。那么，让我们考虑一下，呃，你认为今天在将结构、设备、人，呃，任何东西真正送入太空方面最大的障碍是什么？女学生：嗯，成本，对吗？男教授：没错。我的意思是，仅仅乘坐航天飞机往返一次就非常昂贵。为什么？女学生：我想很多都是燃料，对吧？为了让火箭飞得足够快…男教授：好吧…足够快到。。。？女学生：为了逃避地球引力。男教授：很好。因此，我们在每次发射时都要消耗大量的燃料，以使火箭达到所谓的“逃逸速度”。现在，逃逸速度大约是每秒11公里，相当快。但我们真的要这么快吗？女学生：嗯……是的！我的意思是，你还能怎么逃脱？我的意思是，这就是逃逸速度的全部意义，对吗？否则，地心引力会把你拉回到地球。。。。

男教授：事实上，这是一个普遍的误解。逃逸速度就是物体从大炮中射出的速度，最小初始速度，这样物体就可以自己逃逸地球重力。但这只是如果没有施加额外的力。如果你继续向物体提供力，继续向上推动它。它可以以任何速度脱离地球引力。女学生：真的很慢吗？所以你的意思是，如果你有足够高的梯子，你可以直接爬到太空中？男教授：是的，嗯，理论上。我的意思是，我可以看到梯子例子的一些实际问题。呃，就像你在最初的几千公里后可能会有点累，呃，尤其是你必须带着所有的氧气罐！男教授：不，我想的更多的是电梯……女学生：等等，你是认真的吗？男教授：当然。电梯。对我们大多数人来说，这是一个新想法，但事实上，它已经存在了一个多世纪。如果我们能用太阳能为这样的电梯提供动力，我们就可以简单地升入太空——只需花费火箭或航天飞机旅行的一小部分费用。女学生：但是等等，电梯不只是上升。他们必须挂在某种电线或轨道上。男教授：嗯，是的，几十年来，这正是这个想法不可行，甚至不被认真对待的原因：；嗯，我们在哪里能找到一种足够坚固、重量又足够轻的材料来充当电缆或轨道&nbsp；我的意思是，我们在这里讨论36000公里，电缆上的张力将超过大多数材料所能承受的。

但最近开发的一种新材料的抗拉强度高于金刚石，但它的柔韧性要高得多&nbsp；我说的是碳纳米管。

女学生：好的，我读过一些关于碳纳米管的文章。它们很结实，好吧，但它们只是形状很短的小圆柱体吗？男教授：啊，是的。但这些圆柱体在分子水平上紧密结合在一起。你拔出一根纳米管或一排纳米管，它的邻居和他们的邻居，等等。所以你实际上可以拔出一条36000公里长的比钢更坚固的纳米管，但可能是人类头发厚度的千分之一。女学生：好的，很好。但是，什么能支撑住这条带子，让它够到支撑电梯轿厢的高度呢？男教授：好吧，我们一定要把它固定在两端。所以我们需要的是一个非常高的塔，在赤道的地面上，一颗卫星在地球静止轨道上。我提到36000公里是有原因的。这是关于一个物体必须从赤道垂直向上运行的高度，才能一直保持在旋转行星地球上的同一点的正上方。所以，一旦你在塔楼上方的地球静止轨道上，只要把你的碳纳米管电缆从卫星上放下来，把它拴在地球上的塔楼上。你就在那里！女学生：那么你真的认为这是可能的？比如，这会发生多久？男教授：科幻作家亚瑟·C·克拉克（Arthur C.Clarke）早在20世纪70年代就谈到过建造太空电梯。当有人问他这个想法何时会成为现实时，他的回答是：“大概是在大家都不再笑了50年后。”

三、Carbon Nanotubes托福听力问题：

Q1:1.What is the main purpose of the lecture?

A.To help students understand what is required to launch a satellite

B.To describe new materials now being used to explore space

C.To describe a potential technology for space exploration

D.To show how ideas from science fiction often develop into actual technologies

Q2:2.Why does the student mention climbing a ladder?

A.To demonstrate his familiarity with certain new types of technology

B.To make sure he understands the point the professor is making

C.To raise an objection to the professor's claims about escape velocity

D.To provide a humorous example for the other students'amusement

Q3:3.What does the professor imply about using carbon nanotubes in the development of space elevators？

A.Current technology is good enough to make space elevators even without nanotubes.

B.We do not yet have the technology to bind nanotubes together in a ribbon.

C.Nanotube cables would not be rigid enough to support an elevator car.

D.Nanotubes are the kinds of materials that will be needed if space elevators are ever to be built.

Q4:4.According to the professor,what is the significance of having a satellite in orbit about 36,000 kilometers above Earth's surface?

A.This is the physical limit of the length that a carbon nanotube cable could reach.

B.A satellite orbiting at this height can remain directly above on location on Earth.

C.Earth's gravitational field is too weak to hold a satellite in orbit at higher altitudes.

D.The distance around Earth's equator is approximately 36,000 kilometers.

Q5:5.Why does the professor mention the writer Arthur C.Clarke?

A.To use a comment made by Clarke as a way of answering a student's question.

B.To familiarize students with Clarke's ideas on space engineering.

C.To cite a prominent opponent of the idea of space elevators.

D.To point out that Clarke wrote about carbon nanotube technology long before it became a reality.

Q6:6.What can be inferred about the professor when he says this?

A.He is enjoying an opportunity to make his students laugh.

B.He is disappointed that none of his students thought of this idea themselves.

C.He wants his students to seriously consider an idea they might find surprising.

D.He has spent a great deal of time researching the idea that he is now presenting.

四、Carbon Nanotubes托福听力答案：

A1:正确答案：C

A2:正确答案：B

A3:正确答案：D

A4:正确答案：B

A5:正确答案：A

A6:正确答案：C

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