Science Daily December 7, 2022 The issues arising from the low S mass loading and poor cycling stability caused by the shuttle effect of polysulfides seriously limit the operating capacity and cycling capability of room-temperature sodium–sulfur (RT-Na/S) batteries. An international team of researchers (China, Australia) synthesized sulfur-doped graphene frameworks supporting atomically dispersed 2H-MoS2 and Mo1 (S@MoS2-Mo1/SGF) with a record high sulfur mass loading of 80.9 wt.% as an integrated dual active sites cathode for RT-Na/S batteries. They displayed unprecedented cyclic stability with a high initial capacity and a low-capacity fading rate of 0.05% per cycle over 1000 cycles. Experimental and […]
Paper-thin solar cell can turn any surface into a power source (w/video)
Nanowerk December 10, 2022 To date, demonstrations of ultra-thin photovoltaics have been limited to small-scale devices, often prepared on glass carrier substrates with only a few layers solution-processed. Researchers at MIT have demonstrated large-area, ultra-thin organic photovoltaic (PV) modules produced with scalable solution-based printing processes for all layers. They were transferred onto lightweight and high-strength composite fabrics, resulting in durable fabric-PV systems ∼50 microns thin, weighing under 1 gram over the module are, and having a specific power of 370 W kg−1. Integration of the ultra-thin modules onto composite fabrics lends mechanical resilience to allow the fabric-PV systems to maintain […]
Scientists map heat beneath Antarctica’s icesheets
Phys.org December 13, 2022 Geothermal heat flow (GHF) can reveal past and present plate tectonic processes. In Antarctica, GHF has further consequences in predicting the response of ice sheets to climate change. In a review article an international team of researchers (Australia, Germany, USA – Stony Brook University, Colorado College) discuss variations in Antarctic GHF models based on geophysical methods and draw insights into tectonics and GHF model usage for ice sheet modelling. The inferred GHF at continental scale for West Antarctica points to numerous contributing influences, including non-steady state neotectonic processes. Combined influences cause especially high values in the […]
Signals from the ionosphere could improve tsunami forecasts
Phys.org December 12, 2022 Acoustic-gravity waves propagated by the eruption and tsunami caused global complex ionospheric disturbances. Researchers at the University of Washington studied the nature of the perturbations from Global Navigation Satellite System observables over the southwestern Pacific. After processing data from 818 ground stations, they detected supersonic acoustic waves, Lamb waves, and tsunamis, with filtered magnitudes between 1 and 7 Total Electron Content units. Phase arrivals appeared super positioned up to ∼1,000 km from HTHH and were distinct by ∼2,200 km. Within ∼2,200 km, signals had an initial low-frequency pulse that transitioned to higher frequencies. They found the […]
Studying spinning-induced scattering of sound to create next-generation acoustic devices using new phonon modes
Phys.org December 13, 2022 Understanding the acoustic scattering and radiation force and torque of an object is important in various fields, such as underwater communication, acoustic imaging, and noninvasive characterization, as well as biomedical ultrasound. An international team of researchers (Saudi Arabia, UK, USA – University of Illinois) studied scattering off cylindrical objects in spinning motion around the axis of rotational symmetry to investigate the radiation force and torque induced by various incident signals, e.g., cylindrical diverging and converging beams as well as quasi-Gaussian beams of different orders. The study assumed that the acoustic parameters of the objects (density and […]
Unique modulator could change mid-infrared photonic systems for the better
Phys.org December 12, 2022 Optical modulators are crucial photonic circuits that enable signal switching and routing, data encoding, phase-sensitive detection, and spectroscopic interrogation. Researchers in China have developed a new MIR all-optical modulator based on an acetylene-filled hollow-core fiber. Optical absorption of the control beam promotes the gas molecules to a higher energy level, which induces localized heating through non-radiative relaxation and modulates the refractive index of the gas material and hence the accumulated phase of the signal beam propagating through the hollow-core fiber. By modulating the intensity of the control beam, they modulated the phase of the signal beam. […]
Using lasers to bond semiconductor electronics components
Phys.org December 5, 2022 Important physical limitations have prevented applying laser micro-welding to silicon (Si) and other technology-essential semiconductors. High intensities are required for internal glass modification. However, they result in strong propagation nonlinearities which defocus and delocalize intense infrared radiation. To overcome this, researchers in France created defects inside silicon that later serve as weak points to produce clean-edge cuts. The defects acted as strong bonding points. After setting up the right conditions to circumvent the effects, they successfully made the first experimental demonstration of silicon-silicon laser welding. After an optimization process, they extended the technique to gallium arsenide […]
The Yellowstone Supervolcano Holds Way More Liquid Magma Than We Realized
Science Alert December 8, 2022 An obvious but key requirement for an eruption is the presence of magma. This magma also needs to be distributed so that it can mobilize and erupt as a coherent body. A key issue for eruption hazard assessment is to ascertain how much magma is below the surface and where. Researchers at UC Davis modeled seismic data to image melt beneath the Yellowstone Caldera. They concluded that more melt is present than had been recognized, and it is located at shallow depths in the crust. But the melt fraction they estimated is substantially lower than […]
Top 10 Science and Technology Inventions for the Week of December 9, 2022
01. Quantum leap for research into unhackable communications networks 02. Antiferromagnets are suitable for transporting spin waves over long distances, study finds 03. Flameproofing lithium-ion batteries with salt 04. High-performance and compact vibration energy harvester created for self-charging wearable devices 05. Iron for energy storage 06. Milestone for laser technology 07. New instrument measures supercurrent flow; data has applications in quantum computing 08. On-demand storage of photonic qubits at telecom wavelengths 09. Photonics – extending the spectrum 10. Proposing a new idea for spacecraft propulsion that involves dynamic soaring And others… Researchers advance insights into cause of ripples on icicles […]
Antiferromagnets are suitable for transporting spin waves over long distances, study finds
Phys.org December 6, 2022 In antiferromagnets, the efficient transport of spin-waves has until now only been observed in the insulating antiferromagnet hematite, where circularly polarized spin-waves diffuse over long distances. An international team of researchers (Germany, France, Norway, China) observed long-distance spin-transport in the antiferromagnetic orthoferrite YFeO3, where a different transport mechanism was enabled by the combined presence of the Dzyaloshinskii-Moriya interaction and externally applied fields. The magnon decay length exceeded hundreds of nanometers, in line with resonance measurements that highlight the low magnetic damping. They observed a strong anisotropy in the magnon decay lengths which they attributed to the […]