加拿大研究人员开发雷达“隐身衣”

 　　加拿大研究人员开发雷达“隐身衣”

　　TORONTO, Nov. 25 (Xinhua) --- Witches and magic may not exist, but Harry¹ Potter's invisibility cloak certainly does.

　　A pair of researchers in the Canadian city of Toronto have developed their very own cloaking method that could pretty much make any object disappear not to the human eye yet but on radar².

　　Since 2006, researchers from around the world have been working to create a functioning invisibility cloak using metamaterials artificial materials engineered to steer³ light to hide objects which could be impractical⁴ since the material often had to be as thick and large as the object it was being used to hide.

　　But University of Toronto electrical and computer engineering professor, George Eleftheriades, and Ph.D. candidate Michael Selvanayagam's innovation, published in the latest journal Physical Review X, offer a much different approach.

　　"We were looking at a way to develop a cloaking mechanism⁵ that was different from previous works where they use materials and bend light around the objects, we were trying to use sources to bend light around an object," Selvanayagam explained to Xinhua.

　　The idea is simple, said Eleftheriades. Instead of cloaking with a physical material, they surround the object with antennae⁶ which radiate an electromagnetic field, making it virtually undetectable to microwave and radio wave detectors⁷.

　　"Waves do not bounce around, the light that normally reflects from an object now is cancelled, so if you cancel the reflections, there is no shadow, there are no reflections coming out of the object and so it becomes invisible," he said.

　　To demonstrate their idea, the pair created an apparatus⁸ a contained metal box roughly the size of a pool table. Set in the center of the box is a metal cylinder⁹, which has 12 antennae surrounding it.

　　Each antennae fires waves back to nullify the waves, according to Selvanayam. Likening the metal box to a water tank, the incoming waves, instead of scattering¹⁰ as it hits the object, will then pass through completely unaffected as if the object did not exist.

　　"The wavefronts stay circular now as they travel through because the cloak suppresses the light that scatters¹¹ off the object," said Selvanayagam as he explained the shots taken of the waves before and after the demonstration¹². "And so we can see that the cloaking effect in terms of these wavefronts look like they're just travelling right through."

　　Besides offering up a cool technology, the duo said their work could also have some very practical real-world applications. Other than military use, it could also be used to create extremely thin lenses and devices that wouldn't otherwise be possible. Cell phone signals could also be enhanced by making buildings obstructing¹³ cell phone radiation "disappear."

　　And a Harry Potter like invisibility cloak that can camouflage¹⁴ objects to the naked eye may also become a very real possibility in the near future as technology continues to develop, according to the pair.

　　"If you have a way to make nano-antennas¹⁵ that replace these antennas for radio waves and control what light they radiate, this can become also something that works with the eyes (to make it) invisible," said Eleftheriades. "So it's very scalable, this technology."

　　But the work isn't done yet. The Toronto duo are hoping to continue perfecting the technology. As of now, one of the biggest limitations is that they have to know where the source that's illuminating¹⁶ the object is placed in space since they have to manually take a measurement at each point to reconstruct the image. The next step, Selvanayagam said, is to make the technology fully¹⁷ adaptive so it can respond and adjust in real-time.

　　"Future work with this idea is to make this cloak adaptable¹⁸ so that electronics that feed the cloak and make the cloak work could respond with the incident wave and then adapt with the change of settings so they could cancel out no matter where the object, no matter where the source is," he said.

　　Despite the long road ahead, the duo couldn't be happier with the results they've achieved over the last year-and-a-half.

　　"With any research project you want it to be something that hasn't been done before, so what people haven't thought of," said Selvanayagam. "What we were able to show you is that we were the first people to show you that active cloaking is possible."

　　"You can't really ask for more," he said.

1 harry   

vt.掠夺，蹂躏，使苦恼

参考例句：

• Today,people feel more hurried and harried.今天，人们感到更加忙碌和苦恼。
• Obama harried business by Healthcare Reform plan.奥巴马用医改掠夺了商界。

2 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。

3 steer   

vt.驾驶，为…操舵；引导；vi.驾驶

参考例句：

• If you push the car, I'll steer it.如果你来推车，我就来驾车。
• It's no use trying to steer the boy into a course of action that suits you.想说服这孩子按你的方式行事是徒劳的。

4 impractical   

adj.不现实的，不实用的，不切实际的

参考例句：

• He was hopelessly impractical when it came to planning new projects.一到规划新项目，他就完全没有了实际操作的能力。
• An entirely rigid system is impractical.一套完全死板的体制是不实际的。

5 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

6 antennae   

n.天线；触角

参考例句：

• Sometimes a creature uses a pair of antennae to swim.有时某些动物使用其一对触须来游泳。
• Cuba's government said that Cubans found watching American television on clandestine antennae would face three years in jail.古巴政府说那些用秘密天线收看美国电视的古巴人将面临三年监禁。

7 detectors   

探测器( detector的名词复数 )

参考例句：

• The report advocated that all buildings be fitted with smoke detectors. 报告主张所有的建筑物都应安装烟火探测器。
• This is heady wine for experimenters using these neutrino detectors. 对于使用中微子探测器的实验工作者，这是令人兴奋的美酒。 来自英汉非文学 - 科技

8 apparatus   

n.装置，器械；器具，设备

参考例句：

• The school's audio apparatus includes films and records.学校的视听设备包括放映机和录音机。
• They had a very refined apparatus.他们有一套非常精良的设备。

9 cylinder   

n.圆筒，柱(面)，汽缸

参考例句：

• What's the volume of this cylinder?这个圆筒的体积有多少？
• The cylinder is getting too much gas and not enough air.汽缸里汽油太多而空气不足。

10 scattering   

n.[物]散射；散乱，分散；在媒介质中的散播adj.散乱的；分散在不同范围的；广泛扩散的；（选票）数量分散的v.散射(scatter的ing形式)；散布；驱散

参考例句：

• The child felle into a rage and began scattering its toys about. 这孩子突发狂怒，把玩具扔得满地都是。 来自《简明英汉词典》
• The farmers are scattering seed. 农夫们在播种。 来自《简明英汉词典》

11 scatters   

v.（使）散开， （使）分散，驱散( scatter的第三人称单数 )；撒

参考例句：

• He scatters money about as if he were rich. 他四处挥霍，好像很有钱。 来自《简明英汉词典》
• Truth raises against itself the storm that scatters its seeds broadcast. 真理引起了反对它自己的狂风骤雨，那场风雨吹散了真理的广播的种子。 来自辞典例句

12 demonstration   

n.表明，示范，论证，示威

参考例句：

• His new book is a demonstration of his patriotism.他写的新书是他的爱国精神的证明。
• He gave a demonstration of the new technique then and there.他当场表演了这种新的操作方法。

13 obstructing   

阻塞( obstruct的现在分词 )； 堵塞； 阻碍； 阻止

参考例句：

• You can't park here, you're obstructing my driveway. 你不能在这里停车，你挡住了我家的车道。
• He was charged for obstructing the highway. 他因阻碍交通而受控告。

14 camouflage   

n./v.掩饰，伪装

参考例句：

• The white fur of the polar bear is a natural camouflage.北极熊身上的白色的浓密软毛是一种天然的伪装。
• The animal's markings provide effective camouflage.这种动物身上的斑纹是很有效的伪装。

15 antennas   

[生] 触角，触须（antenna的复数形式）

参考例句：

• Marconi tied several antennas to kites. 马可尼在风筝上系了几根天线。 来自超越目标英语 第3册
• Radio astronomy today is armed with the largest antennas in the world. 射电天文学拥有世界上最大的天线。

16 illuminating   

a.富于启发性的，有助阐明的

参考例句：

• We didn't find the examples he used particularly illuminating. 我们觉得他采用的那些例证启发性不是特别大。
• I found his talk most illuminating. 我觉得他的话很有启发性。

17 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

18 adaptable   

adj.能适应的，适应性强的，可改编的

参考例句：

• He is an adaptable man and will soon learn the new work.他是个适应性很强的人，很快就将学会这种工作。
• The soil is adaptable to the growth of peanuts.这土壤适宜于花生的生长。