University of Pennsylvania March 21, 2019 Researchers at the University of Pennsylvania have introduced a metamaterial platform capable of solving an arbitrary wave as the input function to an equation associated with a prescribed integral operator. The solution of such an equation is generated as a complex-valued output electromagnetic field. They demonstrated their technique at microwave frequencies through solving a generic integral equation and using a set of waveguides as the input and output to the designed metastructures. The research provides a route to develop chip-based analog optical computers and computing elements…read more. TECHNICAL ARTICLE
Category Archives: Advanced materials
Supercrystal: A hidden phase of matter created by a burst of light
Science Daily March 18, 2019 A team of researchers in the US (Pennsylvania State University, Oak Ridge National Laboratory, Argonne National Laboratory, UC Berkeley, Lawrence Livermore National Laboratory) has shown that atomic-scale PbTiO3/SrTiO3 superlattices, counterpoising strain and polarization states in alternate layers, are converted by sub-picosecond optical pulses to a supercrystal phase. This phase persists indefinitely under ambient conditions, has not been created via equilibrium routes, and can be erased by heating. By adjusting only dielectric properties, the phase-field model describes this emergent phase as a photo-induced charge-stabilized supercrystal formed from a two-phase equilibrium state. The research has implications for […]
Materials could delay frost up to 300 times longer than existing anti-icing coatings
Nanowerk March 21, 2019 An international team of researchers (USA – University of Illinois, France) has demonstrated that the use of certain phase‐change materials, called phase‐switching liquids (PSLs), which are in liquid state under ambient conditions and have melting point higher than the freezing point of water can impede condensation–frosting lasting up to 300 and 15 times longer in bulk and surface infused state, respectively. The freezing delay is primarily a consequence of the release of trapped latent heat due to condensation, solidified PSL surface morphology and its miscibility in water. Regardless of surface chemistry, PSL‐infused textured surfaces exhibit low […]
NUS researchers create water-resistant electronic skin with self-healing abilities
Eurekalert March 18, 2019 An international team of researchers (China Singapore) has developed a material inspired by jellyfish. It is composed of a fluorocarbon elastomer and a fluorine-rich ionic liquid, has an ionic conductivity that can be tuned to as high as 10−3 S cm−1 and can withstand strains as high as 2,000%. Owing to ion–dipole interactions, it offers fast and repeatable electro-mechanical self-healing in wet, acidic and alkali environments. It can be printed into soft and pliable ionic circuit boards and touch, pressure and strain sensors. The material has applications in aquatic soft robots and water-resistant human–machine interfaces…read more. TECHNICAL ARTICLE
Nanocoating makes lightweight metal foams bone-hard and explosion-proof
Phys.org March 15, 2019 The metal foams currently available are suitably lightweight, but the production process is complicated and expensive, and the structures are still too weak and not resilient enough for many applications. Inspired by bone, researchers in Germany used aluminium or polymer foam as the initial lattice substrate to manufacture highly stable, porous metallic foams. They developed a proprietary procedure for coating the individual struts that make up the open-cell interior lattice. As a result, the exterior of the foam is stronger, more stable, light and the withstands extreme loads. They found polyurethane foams have a low density, […]
‘Meta-mirror’ reflects sound waves in any direction
Science Daily March 7, 2019 To break the law of reflection with sound waves, an international team of researchers (Finland, USA – Duke University) designed a meta-mirror out of plastic with precisely etched channels on the surface of the metamaterial. Between the meta-mirror’s shape and the depth of its channels, the interference pattern results in the sound wave reflecting in a desired direction without any of its energy being absorbed or scattered in an unwanted direction. In demonstration the device reflected a soundwave traveling directly toward it at 3,000 Hertz and perfectly reflects it at an angle of 70 degrees. […]
Organic electronics: Scientists develop a high-performance unipolar n-type thin-film transistor
Science Daily March 1, 2019 Researchers in Japan used a series of new poly(benzothiadiazole-naphthalenediimide) derivatives and fine-tuned the material’s backbone conformation introducing vinylene bridges capable of forming hydrogen bonds with neighboring fluorine and oxygen atoms. Overall, the resultant material had an improved molecular packaging order and greater strength, which contributed to the increased electron mobility. The material achieved an electron mobility of 7.16 cm2 V-1 s-1, representing more than a 40 percent increase over previous comparable results.The researchers will also aim to improve the air stability of n-channel transistors — a crucial issue for realizing practical applications that would include […]
Material that shields beetle from being burned by its own weapons, holds promise
Science Daily February 25, 2019 The pygidial glands in Carabid beetles manufacture, store and propel toxic chemicals to ward off insect, amphibian and even small mammalian predators. A team of researchers in the US (Pennsylvania State University, University of New Hampshire) found that the tissues in the glandular system transporting the defensive chemicals to be rich in soft, rubbery resilin, a compound found in many insects and other arthropods. Resilin is a compound that is likely to be used in future bioengineering and biomedical applications due to its unusual properties. It has many similarities with elastin, a protein found in […]
Researchers discover anti-laser masquerading as perfect absorber
Phys.org February 15, 2019 Researchers at Duke University constructed zirconia ceramic surface dimpled with cylinders like the face of a Lego brick. After computationally modeling the device’s properties by altering the cylinders’ size and spacing, the researchers realized that they had actually created a more fundamental kind of coherent perfect absorber (CPA) which can absorb both aligned and misaligned waves. Unlike typical CPAs the new material has three variables the cylinders’ radius, height and periodicity. This gives a lot of flexibility for tailoring the CPA model and put them in the frequency spectrum where needed…read more. TECHNICAL ARTICLE
Engineered metasurfaces reflect waves in unusual directions
Nanowerk February 16, 2019 An international team of researchers (Finland, USA – Duke University) introduced purely local reflective metasurfaces for arbitrary manipulations of the power distribution of reflected waves without excitation of any auxiliary evanescent field. The method is based on the analysis of the power flow distribution and the adaptation of the reflector shape to the desired distribution of incident and reflected fields. As a result, they found that these power-conformal metamirrors can be easily implemented with conventional passive unit cells. The results can be used for the design of reflecting surfaces with multiple functionalities and for waves of […]