The singularity of metamaterials makes them have a wide application prospect, from high receiving antennas to radar reflectors, and even earthquake warning.
Metamaterials is an interdisciplinary subject, including electronic engineering, condensed matter physics, microwave, optoelectronics, classical optics, material science, semiconductor science and nanotechnology.
Chinese name: metamaterial mbth: metamaterial category: physical characteristics: disciplines with extraordinary physical properties: materials science: the definition of materials science, six metamaterials, historical evolution, research status, foreign development, China development, development prospects, basic principles, main features, applied research and expert opinions. The definition of "metamaterial" refers to some artificially designed structures with extraordinary physical properties that natural materials do not have. "Metamaterial" is a new material that has appeared since the 20th century. It has special properties that natural materials do not have, and these properties mainly come from the special artificial structure. The design idea of metamaterials is novel. The basis of this idea is to break through the limitations of some apparent natural laws through the design of various physical structures, so as to obtain extraordinary material functions. The design idea of metamaterials shows that people can artificially obtain "new substances" with extraordinary physical properties completely different from nature without violating the basic laws of physics, and bring the design and development of functional materials into a brand-new world. Typical metamaterials include left-handed materials, photonic crystals, super-magnetic materials and metallic water. Six metamaterials 1 and self-repairing materials-bionic plastics Scott White of the University of Illinois developed a bionic plastic with self-repairing ability. This polymer is embedded in the "vascular system" composed of liquid. When it is damaged, liquid can ooze and coagulate like blood. Compared with other materials that can only repair tiny cracks, this bionic plastic can repair cracks as wide as 4 mm. 2. Thermoelectric Materials A company named Alphabet Energy has developed a thermoelectric generator, which can be directly inserted into the exhaust pipe of an ordinary generator to convert waste heat into usable electric energy. This kind of generator uses a relatively cheap and natural thermoelectric material called tetrahedrite, which is said to achieve 5- 10% energy efficiency. Scientists have been studying a thermoelectric material with higher energy efficiency, called skutterudite, a mineral containing cobalt. At present, thermoelectric materials have been used in small scale-for example, on spacecraft-but skutterudite has the characteristics of low cost and high energy efficiency, and can be used to wrap the exhaust pipe of cars, freezers or any machines. 3. Perovskite In addition to crystalline silicon, perovskite can also be used as an alternative material for solar cells. In 2009, the solar conversion rate of solar cells made of perovskite was 3.8%. By 20 14, this number has increased to 19.3%. Compared with the traditional crystalline silicon battery, the energy efficiency is improved by more than 20%. Scientists believe that the performance of this material may still be improved. Perovskite is a material defined by a specific crystal structure. They can contain any number of elements. Generally speaking, lead and tin are used in solar cells. Compared with crystalline silicon, these raw materials are much cheaper and can be sprayed on glass without careful assembly in a clean room. 4. Aerogels Aerogels can be made of many substances, including silicon dioxide, metal oxides and graphene. Aerogel is an excellent insulator because air accounts for a large proportion. Its structure also gives it ultra-high strength and toughness. Scientists of NASA have been experimenting with a flexible aerogel made of polymer as insulation material for spacecraft to cross the atmosphere. 5. Sterene-Material with conductivity of 100% Like graphene, Sterene is also a material composed of monoatomic layers. However, due to the use of tin atoms instead of carbon atoms, it has a characteristic that graphene cannot achieve: 100% conductivity. Professor Zhang Shousheng of Stanford University put forward the theory of steranes for the first time on 20 13. Predicting the electronic properties of sterene and other materials is one of the fields that Professor Zhang's laboratory is good at. According to their model, sterene is a topological insulator, that is, its edge is a conductor and its interior is an insulator. In this way, Stanene can conduct electricity with zero resistance at room temperature. 6. Optical manipulation materials The nanostructures of optical manipulation metamaterials can scatter light in a specific way, which may really make objects invisible. According to different manufacturing methods and materials, metamaterials can also scatter microwaves, radio waves and lesser-known T-rays. In fact, any electromagnetic spectrum can be controlled by metamaterials. During the historical evolution of 1968, Veselago, a theoretical physicist of the former Soviet Union, raised this question and theoretically predicted the above-mentioned "abnormal" phenomenon. Just because there is no experimental verification, and it is in the early stage of the development of functional materials, people have not paid enough attention to the discovery of Fislag. American Science magazine listed it as one of the 10 important scientific progress before this century, which triggered a new generation of major changes in the fields of information technology, national defense industry, new energy technology, micro-processing technology and so on. * * *, academia and industry in developed countries attach great importance to the research and development of metamaterial technology, formulate relevant plans, and invest a lot of manpower and material resources. The U.S. Department of Defense has launched a research project on metamaterials, and six largest semiconductor companies in the United States, such as Intel, AMD and IBM, have also set up joint funds to support this research. The US Department of Defense even listed it as one of the "six subversive basic research fields". The European Union has organized more than 50 top scientists in related fields to focus on research in this field and given them high financial support. During the economic downturn, Japan launched a research plan to support at least two research projects on metamaterial technology, each of which is about 3 billion yen. The present situation of foreign research In the laboratories of scientists all over the world, many novel inventions have appeared. American scientists have made a kind of rebound ceramic tube, which can be recovered after 50% compression compared with traditional brittle hard ceramics. This kind of ceramics will play a great role in "places where ordinary materials can't do anything", such as the heat insulation equipment of space shuttle or jet engine. In 2006, researchers from Duke University in North Carolina and Imperial College London in London successfully challenged the traditional concept by using metamaterials to make objects invisible under microwave radiation. Although there are still many difficulties to overcome, for the first time in history, we have a scheme to make ordinary objects invisible (the research was funded by the Defense Advanced Research Projects Agency (DARPA) of the Pentagon). In Germany, scientists used a technique called "direct laser lithography" to make an invisible material sheet made of tiny plastic rods. When the invisible material sheet covers the object, under the observation of the infrared camera, the invisible material changes the speed of light around the cover, so that the cover and the covered object disappear together. Military organizations, including the Defense Advanced Research Projects Agency (DARPA), are looking for this kind of hiding technology to make the plane invisible within the detection range of military radar. French scientists have found that by accurately drilling holes in metamaterial walls and the ground, seismic waves can be transferred, so that earthquakes and tsunamis can deviate from buildings or towns and achieve the purpose of disaster reduction. Dutch scientists have made smart rubber that can be programmed mechanically. Through the control of small switch and special design, this kind of intelligent rubber can be hardened or softened like an oversized sponge, and even can be quickly deformed in these two stages under extrusion. With the help of this material, people will soon be able to wear shoes that can be automatically adjusted by sensing the hardness of the ground. Compared with the relatively dispersed development mode of many countries, China's development mode in the field of metamaterials is more concentrated and powerful. China supported the research of metamaterials in the 863 Program, the 973 Program, the National Natural Science Foundation and the major projects of new materials. In the basic research of electromagnetic black holes, metamaterial stealth technology, dielectric metamaterial and negative refraction of sound waves, China enterprises have made many original achievements and are in the leading position in the international metamaterial industrialization competition. Liu Ruopeng, who studied in the United States and published a new metamaterial broadband invisibility cloak in Science magazine, is undoubtedly one of the representatives. In 20 10, a team of five overseas students headed by Dr. Liu Ruo Peng returned to China to establish Shenzhen Guangqi. After several years of development, the company has applied for more than 2,800 patents worldwide, accounting for about 86% of the total number of patent applications in related fields. The company is also in the forefront of the world in creating wireless city based on metamaterials, wireless interconnection, aerospace and other fields. For example, it is the world's first precision test line for metamaterial microstructure, with equipment calibration as high as 70% and process accuracy as high as 2 microns. They also designed a standardized process for metamaterial production. Taking the designed electromagnetic metamaterial antenna as an example, using a circuit board that can be folded to the size of a notebook and printed with "Jiangnan Watertown Scenery", airplanes, trains, ships and cars can connect satellite broadband to the Internet in remote places where mobile networks cannot reach. No matter where the satellite is in the sky, the antenna can track it, without staring at the satellite in one direction all the time like the traditional dish antenna. The commercial sales plan of similar products in the United States only started this year, and Guangqi installed and tried it in 22 provinces in China as early as three years ago. This is just one of the fierce competitions between China and the United States in the core field of metamaterials in recent years. In addition, in order to break the monopoly of European and American metamaterials technical standards, last month, the National Technical Committee of Electromagnetic Metamaterials Technology and Product Standardization reviewed and submitted the national standard "Terminology of Electromagnetic Metamaterials". This means that China takes the lead in formulating national standards in the field of metamaterials in the world, which will play an important role in the research and standard transformation of metamaterials technology in China. The development prospect is predicted by a research company. The global market scale of metamaterials will grow at a compound annual growth rate of 465,438+0% from 2065,438+00 to 2020. It can be predicted that with the deepening of the global "Industry 4.0" process and the continuous expansion of the "smart+"application field, a metamaterial industrial cluster with a scale of 100 billion is emerging, which can drive high-speed trains, new ground traveling equipment, aerospace, national defense technology, ground intelligent robots and other fields. Using metamaterial technology to harness electromagnetic waves to build the future world is becoming another focus of global scientific and technological innovation. According to the general theory of relativity, both time and space can be "curved", and so can the light in space, provided that the "equipment" is designed and made small enough. In recent years, following Fislag's theory, scientists have assembled the unit structure of materials (artificial atoms and artificial molecules) by relying on some artificial structures with a spacing of only a few thousandths of 1 mm, and designed and manufactured various metamaterials through different combination structures and arrangements, thus realizing the dream of bending light waves, radar waves, radio waves, sound waves and even earthquake waves. The application of rainbow metamaterials formed by different wavelengths of light captured by special waveguides is very different from the original material preparation. In the past, there were all kinds of materials in nature, but metamaterials were completely reverse designed to produce materials with corresponding functions according to the specific application requirements of electromagnetic waves. Main characteristics Metamaterials have three important characteristics: (1) Metamaterials are usually composite materials with novel artificial structures; (2) Metamaterials have extraordinary physical properties (which are often not found in natural materials); (3)3) The properties of metamaterials are often mainly determined not by the intrinsic properties of the constituent materials, but by the artificial structure. Applied Research At present, the pace of product transformation based on these experimental results is also accelerating. The development and utilization of metamaterial smart skin, metamaterial radar antenna, absorbing material, electronic countermeasure radar, metamaterial communication antenna, UAV radar, acoustic stealth technology and other products have become the focus of competition in various countries. Expert opinion The concept of "metamaterial" has gradually penetrated into many fields. This technology caused a sensation in the field of electromagnetism at first, then went straight to many fields, including thermodynamics, and recently started to make an uproar in the field of mechanics. (Professor Martin Wei Gena of Karlsruhe Institute of Technology, Germany) The promotion of metamaterials to aerospace, national defense and civil science and technology shows that new materials will become a very important entry point and direction in scientific research, which will bring impact and influence to many fields and produce new industries, with far-reaching significance. (Duan Baoyan, Academician of China Academy of Engineering) The design ideas and methods of metamaterials are likely to become a powerful means to explore new functions of materials, lead new directions of industries, improve comprehensive properties of materials and break through the bottleneck of scarce resources. We should further clarify the necessity of vigorously developing metamaterial technology at the national level, concise the development priorities, choose a reasonable technical route, and formulate a metamaterial technology development strategy that conforms to the development trend of metamaterial technology and adapts to China's national conditions. (Zhou Shaoxiong, deputy chief engineer of China Yan Gang Science and Technology Group Co., Ltd.)