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 […]
Flameproofing lithium-ion batteries with salt
Science Daily December 7, 2022 A team of researchers in the US (Stanford University, SLAC National Accelerator Laboratory, UC Berkeley) found that anchored solvent molecules can increase the ionic conductivity of the electrolyte without undermining its non-flammability. They developed a liquid-state polymer electrolyte composed of LiFSI salts, dimethoxyethane (DME) solvents, and polysiloxane tethered with ion-solvating moieties. DME coordinated with both the salt and the polymer, while, together with the salt, they synergistically plasticized the polymer to increase the ionic conductivity. The resulting non-flammable polymer electrolyte had a room-temperature ionic conductivity of 1.6 mS/cm and a wide operation window of 25°C–100°C. […]
High-performance and compact vibration energy harvester created for self-charging wearable devices
Science Daily November 29, 2022 Vibration energy harvesters suffer from a significant drop in performance for non-steady-state vibrations, which are important for practical applications. Researchers in Japan demonstrated that the output power under an impulsive force can be increased significantly by placing a U-shaped metal component, called a dynamic magnifier (DM), under a MEMS piezoelectric vibration energy harvester (MEMS-pVEH) with a Pb(Zr,Ti)O3 film. Based on the results of numerical calculations they designed DM to have the same resonant frequency as the MEMS-pVEH and a high mechanical quality factor (). They measured the waveforms of the output voltage of the fabricated […]
Iron for energy storage
Max-Plank Society December 2, 2022 The combustion of iron powders seems very promising for stable and high-density energy storage technology. To better understand their in-process morphological and microstructural evolution an international team of researchers (Germany, the Netherlands) investigated two iron powder combustion pathways, one in air and one with the assistance of a propane pilot flame. Both processes resulted in spherical hollow particles composed of a complex microstructure of wüstite, magnetite and/or hematite. They observed nanoparticles on the micro-sized combustion products which indicated partial evaporation. According to the researchers the associated gas production inside the liquid droplet could be the […]
Milestone for laser technology
Science Daily December 5, 2022 To make free-electron lasers (FELs) smaller and more cost-effective, an international team of researchers (Israel, Japan, Germany, France, USA – UT Austin) has demonstrated seeded FEL lasing in the ultraviolet regime based on laser-plasma accelerator-driven free-electron laser in a seeded configuration, where control over the radiation wavelength was accomplished. The appearance of interference fringes, resulting from the interaction between the phase-locked emitted radiation and the seed, confirmed longitudinal coherence. Based on their work the researchers anticipate a navigable pathway to extreme-ultraviolet wavelengths, paving the way towards smaller-scale free-electron lasers, unique tools for a multitude of […]