Phys.org September 2, 2021 Quantum dots often suffer from adjacent unwanted emitters, which contribute to the background noise of the QD emission and fundamentally limit the single-photon purity. Researchers in South Korea developed a technique that can isolate the desired quality emitter by reducing the noise surrounding the target with what they have dubbed a ‘nanoscale focus pinspot. The technique is a structurally nondestructive technique under an extremely low dose ion beam and is generally applicable for various platforms to improve their single-photon purity while retaining the integrated photonic structures. Using this technique they focused the ion beam on a […]
Author Archives: Hema Viswanath
Researchers develop novel analog processor for high performance computing
Phys.org August 27, 2021 The lack of modularization and lumped element reconfigurability in photonics has prevented the transition to an all-optical analog computing platform. A team of researchers in the US (George Washington University, UCLA, City College of New York) explored using numerical simulation, a nanophotonic platform based on epsilon-near-zero materials capable of solving in the analog domain partial differential equations (PDE). Wavelength stretching in zero-index media enables highly nonlocal interactions within the board based on the conduction of electric displacement, which can be monitored to extract the solution of a broad class of PDE problems. By exploiting the experimentally […]
‘Tipping points’ in Earth’s system triggered rapid climate change 55 million years ago
Science Daily August 31, 2021 The Paleocene–Eocene Thermal Maximum (PETM) was a period of geologically-rapid carbon release and global warming ~56 million years ago. Although modelling, outcrop and proxy records suggest volcanic carbon release occurred, it has not yet been possible to identify the PETM trigger, or if multiple reservoirs of carbon were involved. An international team of researchers (UK, Denmark, USA – UC Riverside) report that elevated levels of mercury relative to organic carbon—a proxy for volcanism—directly preceding and within the early PETM from two North Sea sedimentary cores, signifying pulsed volcanism from the North Atlantic Igneous Province likely […]
Top 10 Science and Technology Inventions for the Week of August 27, 2021
01. One material with two functions could lead to faster memory 02. An innovative process prevents irreversible energy loss in batteries 03. Laser scribed graphene for supercapacitors 04. High-rate magnesium rechargeable batteries move one step closer to realization 05. New form of carbon in a mesh tantalizes with prospects for electronics 06. New insulation material provides more efficient electricity distribution 07. A new platform for integrated photonics 08. Lightweight composite material inspects itself: Changes in color indicate deformations 09. New Exotic Magnetic Quasiparticle: “Skyrmion Bundle” Joins Topological Zoo 10. Energy harvesting technology based on ferromagnetic resonance And others… Dual-phase alloy […]
Dual-phase alloy extremely resistant to fractures
Phys.org August 20, 2021 An international team of researchers (China, USA – Argonne National Laboratory, University of Tennessee, Germany) has developed a new type of multi-principal element alloys (MPEA) called DS: EHEA (Directly Solidified: Eutectic High-Entropy Alloy) that features multiscale spatial heterogeneities using eutectic high-entropy alloys. They found that a particular aluminum-iron-cobalt-nickel dual-phase alloy solidified in a herringbone micropattern that was very highly resistant to fracturing. Its secret, they discovered, was in its hard and soft phases and the way cracks formed. Those that formed during the hard phase were stopped when they reached a border with a soft phase—the […]
Energy harvesting technology based on ferromagnetic resonance
Phys.org August 24, 2021 Researchers in Japan demonstrated electrical charging using the electromotive force (EMF) generated in a ferromagnetic metal (FM) film under ferromagnetic resonance (FMR). In the case of Ni80Fe20 films, electrical charge due to the EMF generated under FMR can be accumulated in a capacitor; however, the amount of charge is saturated well below the charging limit of the capacitor. In the case of Co50Fe50, electrical charge generated under FMR can be accumulated in a capacitor and the amount of charge increases linearly with the FMR duration time. The difference between the Ni80Fe20 and Co50Fe50 films is due […]
High-rate magnesium rechargeable batteries move one step closer to realization
Science Daily August 23, 2021 Mg/S batteries are some of the most promising rechargeable batteries owing to their high theoretical energy density. However, their development is hindered by low electronic conductivity of S, sluggish Mg2+ diffusion in solid Mg–S compounds formed by discharge, and dissolubility of polysulfides into electrolytes. To address these problems researchers in Japan proposed liquid-S/sulfide composite cathode materials in combination with an ionic liquid electrolyte at intermediate temperatures (∼150 °C). The composite structure is spontaneously fabricated by electrochemically oxidizing metal sulfides, yielding liquid S embedded in a porous metal-sulfide conductive frame. They demonstrated the concept by a […]
In a first, scientists capture a ‘quantum tug’ between neighboring water molecules
Phys.org August 25, 2021 An accurate description of the ultrafast vibrational motion of water molecules is essential for understanding the nature of hydrogen bonds and many solution-phase chemical reactions. An international team of researchers (USA – SLAC National Accelerator Laboratory, UC Davis, University of Nebraska, Stanford University, Sweden) measured the ultrafast structural response to the excitation of the OH stretching vibration in liquid water with femtosecond temporal and atomic spatial resolution using liquid ultrafast electron scattering. They observed a transient hydrogen bond contraction of roughly 0.04 Å on a timescale of 80 femtoseconds, followed by a thermalization on a timescale of […]
An innovative process prevents irreversible energy loss in batteries
Phys.org August 24, 2021 Due to the permanent loss of Li ions that occurs during the initial charge in the stabilization stage of the battery production the theoretical energy density that can be stored in the batteries has not been achieved. To overcome this issue researchers in South Korea have developed an electrode pre-treatment solution capable of minimizing the initial Li ion loss in graphite-silicon oxide composite anodes. After being dipped in the solution, the anode, which was composed of 50% SiOx, demonstrated negligible Li loss, enabling a full cell to exhibit near-ideal energy density. The work highlights the promise […]
Laser scribed graphene for supercapacitors
Nanowerk August 23, 2021 Supercapacitors, which have safe and fast charge (in seconds) and high energy storage are promising for consumer electronics, hybrid electric vehicles and industrial power management. Recently, laser scribed graphene has been increasingly studied for supercapacitor applications. With the laser scribing process, graphene can be directly fabricated and patterned for supercapacitors. Researchers in China summarize recent developments, current challenges and future advancements of supercapacitors based on laser scribed graphene. They summarize facile laser scribing methods for graphene and the application for electrochemical double-layer capacitors, pseudo-capacitors, and hybrid supercapacitors. Recent developments are discussed demonstrating that laser scribing technology […]