Phys.org March 30, 2022 The classical quasi-linear theory of electron precipitation through moderately fast diffusive interactions with plasma waves predicts that precipitating electron fluxes cannot exceed fluxes of electrons trapped in the radiation belt, setting an apparent upper limit for electron precipitation. From low-altitude satellite observations, an international team of researchers (USA – UCLA, France, Japan) has shown that ~100 keV electron precipitation rates often exceed this apparent upper limit. They demonstrated that such superfast precipitation is caused by nonlinear electron interactions with intense plasma waves, which have not been previously incorporated in radiation belt models. The high occurrence rate of […]
Study shows how superconductivity can be switched on and off in superconductors
Phys.org March 30, 2022 Recent experiments have suggested that superconductivity in metallic nanowires can be suppressed by the application of modest gate voltages. The source of this gate action has been debated and either attributed to an electric-field effect or to small leakage currents. An international team of researchers (Switzerland, Italy, USA – IBM, NY) has shown that the suppression of superconductivity in titanium nitride nanowires on silicon substrates does not depend on the presence or absence of an electric field at the nanowire but requires a current of high-energy electrons. The suppression is most efficient when electrons are injected […]
Team achieves 30-fold enhancement of thermoelectric performance in polycrystalline tin selenide
Phys.org March 28, 2022 Tin selenide (SnSe) is known to exhibit a record high energy conversion (ZT) in its single crystal form. However, the performance deteriorates in practical polycrystals because of a low electronic conductivity (σ) and a high thermal conductivity (κ). Researchers in Japan enhanced the ZT of polycrystalline SnSe by demonstrating a high σ and a low κ simultaneously by introducing tellurium (Te) ion into the structure of SnSe. The large-size Te ion in Sn(Se1−xTex) forms weak Sn-Te bonds, leading to the high-density formation of hole-donating Sn vacancies and the reduced phonon frequency and enhanced phonon scattering. This […]
Universal flu vaccine candidate
Science Daily March 30, 2022 The highly conserved 24–amino acid ectodomain of M2 protein (M2e) is a leading candidate for a universal flu vaccine. However, its poor immunogenicity has been a major roadblock in its clinical development. An international team of researchers (Singapore, Australia) successfully leveraged a novel vaccine platform to deliver M2e to immune cells. This allowed them to prove that a single shot immunization containing M2e was able to trigger long-lasting immune responses that could protect effectively against multiple strains of the flu. They demonstrated that this approach significantly enhanced protective immune responses in the context of pre-existing […]
Water as a ‘glue’ for elasticity enhanced, wet attachment of biomimetic structures
Phys.org March 29, 2022 Octopus, clingfish, and larva use soft cups to attach to surfaces under water. Using a novel micro cup, fabricated by two-photon lithography, coupled with in situ pressure sensor and observation cameras, an international team of researchers (Germany, USA – University of Illinois) has detailed the nature of its attachment/detachment under water. It involves elasticity-enhanced hydrodynamics generating “self-sealing” and high suction at the cup-substrate interface, converting water into “glue.” Detachment is mediated by seal breaking. They identified three distinct mechanisms of breaking including elastic buckling of the cup rim. A mathematical model described the interplay between the […]
When a band falls flat: Searching for flatness in materials
Science Daily March 30, 2022 An international team of researchers (USA – Princeton University, France, Germany, China, Spain) has developed a catalog of the naturally occurring three-dimensional stoichiometric materials with flat bands around the Fermi level. They considered 55,206 materials from the Inorganic Crystal Structure Database which provides their structural parameters, space group, band structure, density of states and topological characterization and combined several direct signatures and properties of band flatness with a high-throughput analysis of all crystal structures. From this set they created the Materials Flatband Database website https://www.topologicalquantumchemistry.fr/flatbands/ , with its own search engine for future theoretical and […]
Top 10 Science and Technology Inventions for the Week of March 25, 2022
01. Light derails electrons through graphene (w/video) 02. Novel quantum sensing possibilities with nonlinear optics of diamonds 03. Photonic encryption platform in the ultraviolet and visible 04. Physicists create compressible optical quantum gas 05. Qubits: Developing long-distance quantum telecommunications networks 06. Researchers develop silicon cuboid nanoantenna 07. Researchers develop the world’s first power-free frequency tuner using nanomaterials 08. Single-photon source paves the way for practical quantum encryption 09. A stretchy display for shapable electronics 10. Ultra-compact integrated photonic device could lead to new optical technologies And others… Blow flies can be used to detect use of chemical weapons, other pollutants […]
A stretchy display for shapable electronics
Nanowerk March 23, 2022 A team of researchers in the US (Stanford University, Berkeley National Laboratory, Southern Mississippi University) has developed a material design strategy and fabrication processes to achieve stretchable all-polymer-based light-emitting diodes with high brightness and stretchability (about 100 per cent strain). The final display contains seven layers. Two outer layers are two substrates that encapsulate the device. There are two electrode layers, each followed by charge transporting layers and the light-emitting layer sits sandwiched in the center. When electricity runs through the display, one electrode injects positive charges into the light-emitting layer while the other injects negatively […]
Blow flies can be used to detect use of chemical weapons, other pollutants
Phys.org March 24, 2022 Blow flies sample the environment as they search for water and food sources and can be trapped from kilometers away using baited traps. Researchers at Purdue University exposed three species of blow flies to the chemical warfare agent (CWA) simulants dimethyl methylphosphonate and diethyl phosphoramidate as well as the pesticide dichlorvos, followed by treatment-dependent temperature and humidity conditions. At intervals within a 14-day postexposure period the fly guts were extracted and analyzed. They found that the amount of CWA simulant in fly guts decreased with time following exposure but were detectable 14 days following exposure, giving […]
Direct generation of complex structured light
Phys.org March 18, 2022 An international team of researchers (China, USA – Arizona State University) generated structured transverse mode locking (TML) beams and second harmonic generation (SHG) beams by a sandwich-like microchip laser cavity that was passively Q-switched. They observed many rare SHG far-field beam patterns and their experiments showed good agreement with the simulations. It showed that parametric variation for the TML modes greatly changes the far-field beam patterns of the SHG beam. Generated SHG beam patterns vary with the propagation, and then they remain stable into the far field. The SHG beam patterns were observed to have more […]