NIMS, the University of Tokyo, Niigata University and RIKEN have jointly designed a multilayered metamaterial that realizes ultra-narrowband wavelength-selective thermal emission by combining the machine learning (Bayesian optimization) and thermal emission properties calculations (electromagnetic calculation). The joint team then experimentally fabricated the designed metamaterial and verified the performance. These results may facilitate the development of highly efficient energy devices. Thermal radiation, a phenomenon that an object emits heat as electromagnetic waves, is potentially applicable to a variety of energy devices, such as wavelength-selective heaters, infrared sensors and thermophotovoltaic generators. Highly efficient thermal emitters need to exhibit emission spectrum with narrow bands in practically usable wavelength range..
There are 16,000 transfers of premature babies to medical facilities each year in the UK alone. The babies are often transported over large distances from rural to city locations over significant periods of time, in some cases two hours or more. The ambulances, helicopters or aircraft used are miniaturised intensive care units, containing all the equipment required to keep the baby alive. Researchers developed a special'metamaterial' inspired by a nuclear reactor design that offers protection by combining negative Poisson's ratio and negative stiffness properties simultaneously Researchers built a special'metamaterial' inspired by a nuclear reactor design. It combines two unusual properties known to dampen vibrations to a much greater degree than existing materials.
Researchers have come up with a simple and cheap way of shaping sound waves using a new types of'super-material'. The material can be 3D-printed into fingernail-sized bricks which can be combined into a sheet to control sound. This sheet can then be stuck onto the front of loudspeakers to accurately direct the outgoing sound waves and create audio'hotspots' that only the user can hear. These metamaterial bricks together create a new super-material that manipulates sound. Each of the bricks coil up space and act to slow down sound, meaning that incoming sound waves can be accurately directed to specific audio'hot spots' Metamaterials are a new class of finely-engineered surfaces that perform nature-defying tasks.
Star Trek-style invisibility cloaks are a step closer to becoming reality after scientists developed a material that could make submarines invisible to sonar detectors. The invention deflects sound waves without echoing them back meaning sonar equipment cannot detect it. The device could lead to military submarines that are invisible to enemy sonar, paving the way for an invisibility cloak that deflects light like the device used by the Starship Enterprise spacecraft in the Star Trek film and TV franchise. Radar-evading stealth aircraft are a fixture of the world's air forces but until now underwater craft able to hide from sonar have proved elusive. Researchers developed the new material and incorporated it into a three-foot high prototype (pictured).
The metamaterials on the J-20 are likely to be used for as antennas and absorbers, given that the facility making them specializes in electromagnetic tech. Metamaterial antennas can increase radiated power, resulting in longer-range and more precise radar, as well as powerful jammers and datalinks. In turn, by fine-tuning their structures, metamaterial absorbers can be engineered to absorb specific wavelength ranges, such as those from the radars of enemy fighters and missiles. Such absorbers would likely be put on areas likely to reflect radar waves, such as the edges of canards, weapon bay doors, and engine nozzles. Additionally, metamaterials optimized for infrared radiation can improve the sensitivity of the J-20's infrared sensors for tracking missiles and aircraft.