Phys.org November 10, 2020 The concept of impedance matching has been established in electrical, acoustic, and optical engineering to maximize energy transmission from a source through a media. However, existing design of acoustic impedance matching, which extends exactly by a quarter wavelength, sets a fundamental limit of narrowband transmission. An international team of researchers (China, USA – MIT, Harvard University, Duke University, South Korea, Denmark, Canada, Scotland, Germany) has shown that a class of bioinspired metagel impedance transformers can overcome this limit. The transformer embeds a two-dimensional metamaterial matrix of steel cylinders into hydrogel. Using experimental data of the biosonar […]
DARPA’s plan for an airborne COVID detector
Defense Systems November 11, 2020 The small and variable characteristics of the virus combined with complex indoor environments make using a single detection and measurement technique extraordinarily difficult. Optical environmental sensors, which can offer fast detection times, are not always able to discriminate between benign and pathogenic material. The SenSARS program (Pre-solicitation) aims to overcome these existing challenges to environmental monitoring. DARPA is primarily interested in three use cases: detecting the virus in a 50-cubic-meter office, similar detection in a 300-cubic-meter conference room or classroom, and central monitoring of HVAC systems in buildings up to 10 stories. Solutions must have […]
DARPA Selects Teams to Modify Skin Microbiome for Disease Prevention
DARPA November 6, 2020 The ReVector program aims to maintain the health of military personnel operating in disease-endemic regions limiting exposure to mosquito-transmitted diseases. In order to advance concept of exerting precise control over our microbiomes to provide protection from mosquito-borne diseases, DARPA has awarded ReVector Phase 1 contracts to Stanford University and Ginkgo Bioworks. They are tasked with developing precise, safe, and efficacious technologies to modulate the profile of skin-associated volatile molecules by altering the organisms that are present in the skin microbiome and/or their metabolic processes. Phase 1 of the ReVector program (18 months) will focus on modifying […]
Getting single-crystal diamond ready for electronics
Phys.org November 10, 2020 A limitation of silicon is that high temperatures damage which limits the operating speed of silicon-based electronics. Researchers in Japan fabricated a single-crystal diamond wafer and polished it using plasma-assisted polishing to be nearly atomically smooth. Common methods of polishing the surface are slow and damaging to the material. The polished surface was unaltered chemically. The only detected impurity was a small amount of nitrogen from the original wafer preparation. The procedure can help replace some of the silicon components of electronic devices with diamond…read more. Open Access TECHNICAL ARTICLE
Invisible organic light-emitting diodes reach new world record
EurekAlert November 11, 2020 Inspired by a class of molecules previously used for biomedical imaging researchers in Canada developed two new organic compounds with emission peak at a wavelength of 840 nm. The OLED showed a quantum efficiency of 3.8%. The latter corresponds to the percentage of electrons circulating throughout the device, electrons which are then converted into useable light. The efficiency is more than three times higher than that of the best previously reported fluorescent OLEDs in this spectral range and approaches that achievable with the best platinum‐containing phosphorescent emitters. The device has possible applications in biomedicine, facial recognition, […]
New tractor beam has potential to tame lightning
Phys.org November 11, 2020 Numerous experiments utilizing powerful pulsed lasers with peak-intensity above air photoionization and photo-dissociation have demonstrated excitation and confinement of plasma tracks in the wakes of laser field. An international team of researchers (Australia, USA – UCLA) developed and demonstrated an efficient approach for triggering, trapping, and guiding electrical discharges in air. It is based on the use of a low-power continuous-wave vortex beam that traps and transports light-absorbing particles in mid-air. They found a 30% decrease in discharge threshold mediated by optically trapped graphene microparticles with the use of a laser beam of a few hundred […]
New approach to circuit compression could deliver real-world quantum computers years ahead of schedule
EurekAlert November 12, 2020 “Quantum advantage” has been achieved in Noisy Intermediate-Scale Quantum (NISQ) devices in early proof-of-principle experiments. But the NISQ devices are still prone to lots of errors that accumulate during their operation. To negate the need for millions of physical qubits for a fault-tolerant computer researchers in Japan proposed the use of the ZX-calculus as an intermediate language for braided circuit compression in large-scale fault-tolerant quantum computers. According to the researchers by compressing quantum circuits, they could reduce the size of the quantum computer and its runtime, which in turn lessens the requirement for error protection…read more. […]
The next biometric identifier? 3D images of your finger veins
Technology.org November 10, 2020 Biometric methods based on finger veins, as compared to face and fingerprints, obviate privacy concerns and degradation due to wear, age, and obscuration. However, they are 2D and are fundamentally limited by conventional imaging and tissue-light scattering. A team of researchers in the US (SUNY Buffalo, industry) has developed a method of 3D finger vein biometric authentication based on photoacoustic tomography. Using a compact photoacoustic tomography setup and a novel recognition algorithm, they demonstrated the advantages of the 3D biometrics method. Tests of the method on people showed that it can correctly accept or reject an […]
Power-free system harnesses evaporation to keep items cool
MIT News November 11, 2020 A camel’s coat, or a person’s clothing, can help to reduce loss of moisture while at the same time allowing enough sweat evaporation to provide a cooling effect. Tests have showed that a shaved camel loses 50 percent more moisture than an unshaved one, under identical conditions. Researchers at MIT have developed a system with a two-layer material with the bottom layer, substituting for sweat glands. It consists of hydrogel, a gelatin-like substance that consists mostly of water, contained in a sponge-like matrix from which the water can easily evaporate. This is covered with an […]
Scientists uncover secrets to designing brain-like devices
Phys.org November 10, 2020 To create devices that mimic what occurs in our brain’s neurons and synapses, researchers need to overcome a fundamental molecular engineering challenge: how to design devices that exhibit controllable and energy-efficient transition between different resistive states triggered by incoming stimuli. A team of researchers in the US (University of Chicago, Argonne National Laboratory) investigated the defective cobaltites and unraveled the structural, electronic, and magnetic changes responsible for the metal-to-insulator transition (MIT) when oxygen vacancies are introduced in the material. They showed that cooperative structural distortions instead of local bonding changes are responsible for the MIT, described […]