#科技头条#【哈利波特的隐形衣变成了现实?】

#科技头条#【哈利波特的隐形衣变成了现实?】目前英国科学家最新研制一种纳米颗粒材料,具有7个不同的层结构,涂在物体表面可使物体隐形。该材料设计是基于转换光学,由纳米微粒构成,能弯曲物体表面,使电磁波“变平”。研究表明该材料可应用于其它工程应用领域,如纳米-天线和航空工业。http://www.looooker.com/?p=31079

Are invisibility cloaks on their way? New material can make objects 'disappear' by stopping them scattering radio waves

  • Coated object in seven layers of materials made of nano-sized particles
  • The device made curved surfaces appear flat to electromagnetic waves
  • Researchers say technology could be used to change shapes of antennae

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From Star Trek to Harry Potter, invisibility cloaks are a popular theme in science fiction that has led to scientists around the world to strive to turn the technology into a reality.

Now, experts in London have made an object completely 'disappear' by coating it in a material made of tiny particles.

Their cloaking device made curved surfaces appear flat to electromagnetic waves.

The researchers, from Queen Mary University of London (QMUL), coated a curved surface with a material made of nano-sized particles.

The 'composite' material had seven distinct layers, where the electric property of each layer varies depending on the position.

The combined effect of all of these layers is to 'cloak' the object. This means a structure can hide an object that would normally have caused an incoming electromagnetic wave to be scattered.

The technology worked on waves between 8 and 10 Giga Hertz in frequency, in radio part of the electromagnetic spectrum.

This band of frequencies is also known as the centimetre band or centimetre wave as the wavelengths range from one to ten centimetres.

The wavelength of these low frequency waves are long, much longer than light.

Because of the difficulty of building antennas that can radiate such frequencies, antenna size reduction is often required in modern communication systems.

'The design is based upon transformation optics, a concept behind the idea of the invisibility cloak,' said co-author and electrical engineer Professor Yang Hao said.

The researchers said the technology might not lead to the invisibility cloak made famous in J.K Rowling's Harry Potter novels quite yet.

But they said it a practical demonstration could result in a step-change in how antennas are tethered to their platform.

It could allow for antennas in different shapes and sizes to be attached in awkward places and a wide variety of materials.

'Previous research has shown this technique working at one frequency,' said Professor Hao.

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'However, we can demonstrate that it works at a greater range of frequencies making it more useful for other engineering applications, such as nano-antennas and the aerospace industry.'

The design has wider applications, ranging from microwave to optics for the control of any kind of electromagnetic surface waves.

'The study and manipulation of surface waves is the key to develop technological and industrial solutions in the design of real-life platforms, for different application fields,' said first author Dr Luigi La Spada.

'We demonstrated a practical possibility to use nanocomposites to control surface wave propagation through advanced additive manufacturing.

'Perhaps most importantly, the approach used can be applied to other physical phenomena that are described by wave equations, such as acoustics. For this reason, we believe that this work has a great industrial impact.'

原文链接:http://www.dailymail.co.uk/sciencetech/article-3690542/Are-invisibility-cloaks-way-New-material-make-objects-disappear-stopping-scattering-light-waves.html


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