第四十六篇
Marvelous Metamaterials
Invisibility cloaks1 would have remained impossible，forever locked in science fiction，had it not been for the development of metamaterials2.In Greek，“meta” means beyond，and metamaterials can do things beyond what we see in the natural world-like shuffle light waves around an object，and then bring them back together3.If scientists ever manage to build a full-fledged invisibility cloak，it will probably be made of metamaterials.
“We are creating materials that don’t exist in nature，and that have a physical phenomenon that doesn't exist in nature，”says engineer Dentcho Genov. “That is the most exciting thing.” Genov designs and builds metamaterials-such as those used in cloaking-at Louisiana Tech University in Ruston，Louisiana4.
An invisibility cloak will probably not be the first major accomplishment to come from the field of metamaterials. Other applications are just as exciting. In many labs，for example，scientists are working on building a hyperlens. A lens is a device-usually made of glass-that can change the direction of light waves. Lenses are used in microscopes and cameras to focus light，thus allowing a researcher to see small things or a photographer to capture image of things that are far away.
A hyperlens，however，would be made of metamaterials. And since metamaterials can do things with light that ordinary materials can't，the hyperlens would be a powerful tool. A hyperlens would allow researchers to see things at the smallest scale imaginable-as small as the wavelength of visible light.
Genov points out that the science of metamaterials is driven by the imagination：If someone can mink of an idea for a new behavior for light，then the engineers can find a way to design a device using metamaterials. “We need people who can imagine，”he says.
Since 2006，many laboratories have been exploring other kinds of metamaterials that don't involve just visible light. In fact，scientists are finding that almost any kind of wave may respond to metamaterials.
At the Polytechnic University of Valencia in Spain5，Jose Sanchez-Dehesa is working with acoustics, or the science of sound. Just as an invisibility cloak shuffles waves of light，an “acoustic” cloak would shuffle waves of sound in a way that’s not found in nature. In an orchestra hall，for example. an acoustic cloak could redirect the sound waves-so someone sitting behind a column would hear the same concert as the rest of the audience，without distortion.
Sanchez-Dehesa，an engineer，recently showed that it's possible to build such an acoustic cloak, though he doubts we’ll see one any time soon. “In principle，it is possible，”he says，but it might be impossible to make one，he adds.
Other scientists are looking into ways to use larger metamaterials as shields around islands or oil rigs6 as protection from tsunamis. A tsunami is a giant, destructive wave. The metamaterial would redirect the tsunami around the rig or island，and the wave would resume its journey on the other side without causing any harm.
词汇：
cloak n.斗篷，披风 hyperlens n.超透镜
metamaterial n.超材料 acoustics n.声学
full-fledged adj.完全成熟的，完全合格的tsunami n.海震，海啸
注释：
1.Invisibility cloaks：隐形衣。在《哈利.波特与死亡圣器》(Harry Potter and the Deathly Hallows)一书中，哈利通过邓布利多的转交继承了他父亲的隐形衣。该书是英国女作家J.K.罗琳创作的哈利.波特系列小说的第7部。
2.…had it not been for the development of metamaterials：……如果超材料尚未得到开发的话。该句使用的是虚拟过去时的倒装结构。虚拟过去时表示与过去事实相反的假设;因为是倒装结构，所以将情态动词had提到主语之前。如使用正常语序，该句可写为....if it had not been for the development of metamaterials.
3.“meta”means beyond, and metamaterials can do things beyond what we see in the natural world-like shuffle light waves around an object，and then bring them back together：“meta"的词义是“超越”，metamaterials(超材料)能做出我们在自然界看不到的事情，例如将光波移动到某个物体周围，然后将光波全部收回。
4.Louisiana Tech University in Ruston，Louisiana：路易斯安那理工大学，位于路易斯安那州拉斯顿市。该校为公立大学，1894年建校，是美国最为重要的研究型大学之一。
5.the Polytechnic University of Valencia in Spain：瓦伦西亚理工大学，位于西班牙东南部的瓦伦西亚市，该校建于1968年。
6.oil rigs：石油钻塔
练习：
1.What is true for metamaterials?
A.They will always remain in science fiction.
B.They are already a reality.
C.They are nonexistent in nature.
D.Scientists begin to use them to build invisible cloaks.
2.A hyperlens is a more powerful tool than a traditional lens
A.as it can allow scientists to see small things.
B.as it can help photographers to capture images far away.
C. even if it is made of ordinary materials.
D.as it can help scientists to see even the wavelengths of visible light.
3.Scientists at the Polytechnic University of Valencia try to invent
A.an acoustic cloak that can shuffle waves of light.
B.an invisible cloak that can shuffle waves of sound.
C.an acoustic cloak that can shuffle waves of sound.
D.a cloak that is made of materials found in nature.
4.According to Sanchez-Dehesa，
A.it is of great possibility to build an acoustic cloak soon.
B.it is possible to build an acoustic cloak in theory but far from reality.
C.it is totally impossible to build an acoustic cloak.
D.it is theoretically impractical to build an acoustic cloak.
5.What ways are some scientists looking into to protect the island and oil rig from tsunamis?
(Read the last paragraph.)
A.Surround them with metamaterials as protective shields.
B.Stopping the tsunami with metamaterials hours before it reaches them.
C.Building them with larger metamaterials to keep away tsunamis.
D.Using the equipment made of metamaterials to forecast arrival of a tsunami.
答案与题解：
1.C A不是正确答案，因为短文一开始的句子使用了虚拟语态，句子的意思是：如果超
材料尚未得到开发的话……。也就是说，科学家已经在研发超材料。短文的后面部分也进一步提到科学家正致力于超材料的开发。但是因为超材料尚未研发成功，科学家更没有开始使用超材料来制造隐身衣，所以B和D也不是正确选择。第二段的第一句提供了答案。
2.D A、B所述功效均是第三段中普通的lens能够达到的功效，所以不是正确选择。Hyperlens不是用普通材料制成，所以C也是错误选择。短文第四段对hyperlens做了描述，
结合第四段内容可以得到D选项提供的结论。
3.C短文的第七段提供了答案。该段的大意是：瓦伦西亚理工大学的研究者Jose Sanchez-Dehesa试图研发acoustic cloak，其原理与invisible cloak相同，只是acoustic cloak移动声波(shuffle waves of sound)，而不是移动光波(shuffle waves of light)。所以，只有C是正确的选择。
4.B 短文的第八段提供了答案。工程师Sanchez-Dehesa认为，成功开发acoustic cloak在理论上是可能的，但他对是否能成功表现出怀疑。
5.A 短文的最后一段告诉我们，科学家也在研究如何将超材料应用于抵御海啸的袭击。可以在岛屿周围使用超材料作为防护(shields)，因为超材料可以让海啸改变行走方向(redirect tsunami)。A表达了这层意思，所以是答案。文章没有说，在海啸到达之前数小时用超材料
将海啸档住，B不是答案。文章没有建议用超材料建造海岛和石油钻塔，C不是答案。D的内容是用超材料制作海啸预警器，文章中没有提及，也不是答案