2016年职称英语理工类概括大意试题
Maglev Trains
1 A few countries are using powerful electromagnets to develop high-speed trains, called maglev trains. Maglev is short for magnetic levitation 1 , which means that these trains float over a guide way using the basic principles of magnets to
replace the old steel wheel and track trains.
2 If you’ve ever played with magnets, you know that opposite poles attract and like poles repel each other2. This is the basic principle behind electromagnetic propulsion. Electromagnets are similar to other magnets in that they attract metal objects, but the magnetic pull is temporary. You can easily create a small electromagnet yourself by connecting the ends of a copper wire to the positive and negative ends of an AA—cell battery3. This creates a small magnetic field. If you disconnect either end of the wire from the battery, the magnetic field is taken away.
3 The magnetic field created in this wire-and-battery experiment is the simple idea behind a maglev train rail system. There are three components to this system: A large electrical power source, metal coils lining a guide way or track, and large guidance magnets attached to the underside of the train.
4 The big difference between a maglev train and a conventional train is that maglev trains do not have an engine — at least not the kind of engine used to pull typical train cars along steel tracks4. The engine for maglev trains is rather innoticeable. Instead of using fossil fuels, the magnetic field created by the electrified coils in the guideway walls and the track combines to propel the trains5.
5 The magnetized coil running along the track, called a guideway, repels the large magnets on the train’s undercarriage, allowing the train to levitate between 1 to 10 cm above the guideway. Once the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push th train along the guideway. The electric current supplied to the coils in the guideway walls is constantly alternating to change the polarity of the magnetized coils. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust.
6 Maglev trains float on a cushion of air’ , eliminating friction. This lack of friction allows these trains to reach unprecedented ground transportation speeds of more than 500 kph, or twice as fast as the fastest conventional train. At 500 kph, you could travel from Paris to Rome in just over two hours.
词汇:悬浮electrified v.使带电 n. 悬浮magnetize v. 使带磁 导向槽line v.排列成行 推进underside n.下侧,下面 n.推进 undercarriage n.车盘
注释:
1. Maglev is short for magnetic levitation :maglev 是 magnetic levitation 的 缩略词。
2. opposite poles attract and like poles repel each other:异极相吸,同极相斥
3. AA—cell battery:5 号电池
4. at least not the kind of engine used to pull typical train cars along steel tracks:至少不是沿着轨道拉动典型的火车车厢的那种发动机。
5. the magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train:由嵌入导向壁内的电磁线圈产生的磁场加 上轨道,一起推动火车前进。The magnetic field和the track是句子主语,created by the electrified coils in the guideway walls 是过去分词短语,用作定语,修饰 the magnetic field.
练习:
1. Paragraph 3
2. Paragraph 4
3. Paragraph 5
4. Paragraph 6
A The Main Components of the Maglev Train System B High-speed Maglev due to Zero Friction C The Working Principle of the Maglev Train D Differences between Polarity and Magnetic Field E Comparison of Maglev Trains with Traditional Ones F Maglev with a Powerful Motor
5. Several countries in the world are using strong electromagnets
6. You can connect a wire to the positive and negative ends of a battery
7. A unique system of magnetic fields is created by the coils
8. The frictionless maglev train enables you A to develop a maglev train rail system
B To explain why maglev trains are faster
C to pull and push the train forward
D to create a magnetic field
E to experiment with the maglev train
F to travel from Paris to Rome in about two hours
答案与题解:
1. A第三段了举了磁浮列车的三个组成部分,动力源、金属线圈和此贴。选项A概括 了第三段列的内容。
2. E第四段就磁浮列车和传统火车进行了比较:磁浮列车没有发动机而传统火车有发 动机。选项C用comparsion来概括是准确的。
3. C第五段比较详细的介绍了为什么磁浮列车会向前运动,也就揭示了磁浮列车的工作原理。
4. B在第五段解释了磁浮列车浮起和向前运动的原理之后,作者在第六段中进行了磁 浮列车速度奇快的原因:去除了传统火车的车轮于铁轨的摩擦。
5. A选A的依据是本文第一段第一句:A few countries using powerful electromagnets to develop high-speed trains, called maglev trains.
6. D第二段说,把电线与干电池相连接就能产生一个小磁场,而磁浮列车的运动原理与 此相同。第二段第四句是选择D的依据。
7. C 第五段的第二句,即 “0nce the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway” ,是选择 c 的依据。
8. F本文最后一句举出坐上时速500公里的磁浮列车从巴黎到罗马只需约2小时这个例 子来说明磁浮列车速度之快。
译文:磁悬浮列车
一些国家正在使用强有力的额电磁体发展高速列车,这种列车叫作磁悬浮列车。Maglev 是磁悬浮的缩略词,它意味着这些列车漂浮在导向槽上,导向槽是使用磁铁的基本原理来替 换原来的钢轮子和钢轨道的列车。
如果你曾经玩过磁铁,你知道异极相吸,同极相斥的道理。这是电磁式推进背后的基 本原理。电磁体与其他磁铁在吸引金属物品方面是一样的,但是电磁力是暂时的。你能通过 铜丝连接一节5号电池的正负极很容易地自己创造出一个小的电磁体。这就创造了一个小磁 场。如果你从电池分开导线的任意一个末端,磁场就消失。
这个导线和电池实验创造的磁场是磁悬浮列车系统背后的简单想法。这个系统有三个成 分:一个大电能来源、金属卷排列成导向槽或轨道和附着在列车下面的大的导电磁体。
磁悬浮列车和传统列车之间的一个很大的大区别是磁悬浮列车没有发动机一一至少不 是沿着轨道拉动典型的火车车厢的那种发动机。磁悬浮列车的发动机相当不显眼。代替矿物 燃料的使用,由嵌入导向壁内的电磁线圈产生的'磁场加上轨道,一起推动火车前进。
导向槽是沿着轨道延伸的带磁性的线圈。它排斥在列车的车盘上的大磁铁,允许列车在 导向槽之上1一10cm之间悬浮。一旦列车被悬浮,就把力量供给在导向槽墙体之内的线卷来 创造出一个单独的磁场系统,沿着导向槽推拉列车。在导向槽墙体内供给线圈的电流不断交 替改变被磁化的线卷的极性。在极性上的变化造成了列车前面的磁场向前拉动列车,而在列 车后面的磁场增加更多向前推力。
磁悬浮列车漂浮在气垫上来减少摩擦。这种缺乏摩擦(的状态)让这些列车超过500kph 的速度,(这个速度)是地面交通工具史无前例的速度,或者是最快的传统列车两倍的速度。 500kph,你可能用刚好超过两个小时的时间从巴黎旅行到罗马。
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