Nanowerk June 15, 2021 Perfect optical cloaking requires the total scattering of electromagnetic waves around an object at all angles, all polarizations, over a wide frequency range, irrespective of the medium. By simplifying the invisibility requirements, pioneering work on spherical transformation cloaks, carpet cloaks, plasmonic cloaks, and mantle cloaks has been realized in narrowband microwave, infrared, and even optical wavelengths. In a tutorial a team of researchers in the US (University of Michigan, industry) review the theoretical basis for invisibility cloaking, from spherical transformational optics to non-Euclidian cases, and discuss their limitations. Because the human eye is insensitive to the […]
Category Archives: Uncategorized
Surpassing the lower limit on computing energy consumption
Phys.org April 20, 2021 Researchers in Australia have confirmed the potential for topological materials to substantially reduce the energy consumed by computing. They demonstrated that the subthreshold swing of a topological transistor in which conduction is enabled by a topological phase transition via electric field switching, can be sizably reduced in a noninteracting system by modulating the Rashba spin–orbit interaction. By developing a theoretical framework for quantum spin Hall materials with honeycomb lattices, they showed that the Rashba interaction can reduce the subthreshold swing by more than 25% compared to Boltzmann’s limit in currently available materials but without any fundamental […]
This hydrogen fuel machine could be the ultimate guide to self-improvement
Science Daily April 5, 2021 Development of an efficient and durable photoelectrode is important for the deployment of solar-fuel production. A team of researchers in the US (Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, University of Michigan) has shown the photoelectrochemically self-improving behaviour of a silicon/gallium nitride photocathode for hydrogen production with efficiency approaching ~100%. Using correlative approach based on different spectroscopic and microscopic techniques, and density functional theory calculations, they provided a mechanistic understanding of the chemical transformation as the origin of the self-improving behaviour. A thin layer of gallium oxynitride forms on the side walls of the […]
Top 10 Science and Technology Inventions for the Week of April 2, 2021
01. A robot that senses hidden objects 02. Detecting hidden signals 03. Scientists develop ultra-thin terahertz source 04. Study shows promise of quantum computing using factory-made silicon chips 05. Discovery of a mechanism for making superconductors more resistant to magnetic fields 06. Fast-acting, color-changing molecular probe senses when a material is about to fail 07. First steps towards revolutionary ULTRARAM™ memory chips 08. A new spin on energy-efficient electronics 09. Special heat treatment improves novel magnetic material 10. Researchers first to link silicon atoms on surfaces And others…
Army Trains AI to Identify Faces in the Dark
IEEE Spectrum March 9, 2021 To develop a nighttime and low-light face recognition capability for the unconstrained or difficult lighting settings a team of researchers in the US (West Virginia University, Army Research Laboratory, Johns Hopkins University, University of Nebraska, industry) unveiled a dataset called Research Laboratory Visible-Thermal Face Dataset (ARLVTF) with over 500,000 images from 395 subjects. The data was captured using a LWIR camera mounted alongside a stereo setup of three visible spectrum cameras. Variability in expressions, pose, and eyewear were systematically recorded. The dataset has been curated with extensive annotations, metadata, and standardized protocols for evaluation. The […]
Microwave-assisted recording technology promises high-density hard disk performance
Science Daily March 9, 2021 Researchers in Japan analyzed the operation of the flux-control (FC) device by measuring the temporal resistance change in the sub-nanosecond region. They showed that the reversal of the FC device becomes faster as the bias current is increased and can be completed by 0.5 ns after the transition of the write current. They reproduced the experimental results by micromagnetic simulations using a head model, confirming that the simulations correctly describe the magnetization dynamics of the actual device. The simulations showed that the recording field gain by the FC device appears with little delay after the rise […]
New concept for rocket thruster exploits the mechanism behind solar flares
Science Daily January 28, 2021 Current plasma thrusters that use electric fields to propel the particles can only produce low specific impulse. The device proposed by researchers at Princeton Plasma Physics Laboratory would apply magnetic fields to cause particles of plasma to shoot out of a rocket and propel the craft forward. The particles are accelerated using magnetic reconnection which also occurs in tokamaks. They showed that the new plasma thruster concept can generate exhaust with velocities of hundreds of kilometers per second, 10 times faster than those of other thrusters. According to the researchers the new concept provides the […]
The first steps toward a quantum brain
EurekAlert February 1, 2021 The quest to implement machine learning algorithms in hardware has focused on combining various materials to create device functionality. This approach limits functionality, efficiency, complicates scaling and on-chip learning. Researchers in the Netherlands created an atomic spin system that emulates a Boltzmann machine directly in the orbital dynamics of one well-defined material system. They fabricated the prerequisite tunable multi-well energy landscape by gating patterned atomic ensembles using scanning tunneling microscopy. The anisotropic behaviour of black phosphorus, provided plasticity with multi-valued and interlinking synapses that led to tunable probability distributions. They observed an autonomous reorganization of the […]
Iceland Genetically Sequences Every COVID-19 Case in World-Leading Strategy
Science Alert January 17, 2021 Researchers at the biopharma group deCODE Genetics’ laboratory in Iceland have analyzed all the around 6,000 COVID-19 cases reported in Iceland making it the world leader in COVID sequencing. They have identified 463 separate variants – which scientists call haplotypes. Authorities have used the sequencing information to decide on precise, targeted measures to curb the spread of the virus. South African variant has not been detected in Iceland, 41 people have been identified as carriers of the British variant. If there are differences between viruses with the various pattern mutations, they are not obvious. While […]
Scientists in Japan Just Found a Detailed Record of Earth’s Last Magnetic Switcharoo
Science Alert October 31, 2020 Every 200,000 to 300,000 years, Earth’s magnetic poles reverse. The last reversal was unusual because for some reason, the poles have remained oriented the way they are now for about three-quarters of a million years. Researchers in Japan collected new samples and conducted paleo- and rock-magnetic analyses of samples from the Chiba composite section which is considered to contain the most detailed marine sedimentary record of the Matuyama-Brunhes geomagnetic reversal. It provides the most reliable chronostratigraphic framework of the time period around the Brunhes-Matuyama reversal. According to their study it took about 20,000 years, including […]