bluuebunny/crossref_metadata_2025 huggingface dataset:
Stable CsPbX3 mixed halide alloyed epitaxial films prepared by pulsed laser deposition
Authors: Zhou Yu , Yuan Beilei , Wei Haoming , Xu Fan , Li Yujiao , Chen Xin , Cao Bingqiang
Published: March 2022

The pulsed laser deposition (PLD) technique has been proved to be able to grow oxide thin films with high structural quality with precisely controlled composition and thickness to achieve designed optical and electronical properties established in alloyed semiconductors and heterostructures. In this Letter, inorganic halide perovskite CsPb(IxClyBr1−x−y)3 epitaxial alloyed films on (001)-SrTiO3(STO) substrates were grown by PLD. The film crystal quality, phase stability, and the epitaxial relationship between the film and substrate were characterized with a detailed x-ray diffraction technique like high-resolution reciprocal spatial mapping and ϕ-scan. In addition, the photocarrier dynamics of the alloyed epitaxial films were investigated by photophysics spectroscopy, including steady and femtosecond transient optical absorption spectroscopy and temperature-dependent and time-resolved photoluminescence spectroscopy. The bandgap of the CsPbX3 films was tuned from 1.75 to 2.98 eV by substituting X with I/Br/Cl and their mixture of different ratios. Free exciton emissions were observed at a low temperature photoluminescence spectrum (PL, 10 K), which confirmed the high crystal and optical quality of the epitaxial perovskite alloyed films except the CsPbI3 film. The femtosecond transient absorption spectra also showed that such perovskite films are of very low concentration of exciton trap states. These results indicated that PLD is a powerful technology for growing high quality inorganic halide perovskite films with a tunable bandgap covering the full visible light range, which provided more options for CsPbX3 based panchromatic LED and other optoelectronic devices.
Visible-light photoelectrochemical photodetector based on In-rich InGaN/Cu2O core-shell nanowire p–n junctions
Authors: Wang Jialin , Song Jiaxun , Qin Ling , Peng Yingchun , Nötzel Richard
Published: March 2022

n-InGaN/p-Cu2O core-shell nanowire (NW) p–n junctions enable efficient self-powered photoelectrochemical photodetectors (PEC PDs) in the visible. The photocurrent density under one-sun illumination is enhanced by 8 times compared to that of bare InGaN NW PEC PDs due to maximized photocarrier separation in the built-in electric field of the p–n junction. The responsivity reaches 173 μA/W under one-sun illumination. The response times of 30–40 ms are among the shortest achieved for PEC PDs. Together with the long-time stability and reusability, a robust, easy to fabricate, and easy to operate self-powered PEC PD is introduced.
High-speed imaging of magnetized plasmas: When electron temperature matters
Authors: Vincent Simon , Dolique Vincent , Plihon Nicolas
Published: March 2022

High-speed camera imaging is a powerful tool to probe the spatiotemporal features of unsteady processes in plasmas, usually assuming light fluctuations to be a proxy for the plasma density fluctuations. In this article, we systematically compare high-speed camera imaging with simultaneous measurements of the plasma parameters—plasma density, electron temperature, and floating potential—in a modestly magnetized Argon plasma column at low pressure (1 mTorr, magnetic fields ranging from 160 to 640 G). The light emission was filtered around 488 ± 5, 750 ± 5, and 810 ± 5 nm. We show that the light intensity cannot be interpreted as a proxy for the plasma density, and that the electron temperature cannot be ignored when interpreting high-speed imaging, both for the time-averaged profiles and for the fluctuations. The features of plasma parameter fluctuations are investigated, with a focus on ion acoustic waves (at frequency around 70 kHz) at low magnetic field and low-frequency azimuthal waves (around a few kHz) at larger magnetic fields. An excellent match is found between the high-speed images fluctuations and an Arrhenius law functional form, which incorporates fluctuations of the plasma density and of the electron temperature. These results explain the discrepancies between ion saturation current and narrow-band imaging measurements previously reported in the literature.
Beam optics analysis on magnetic-state-selected atomic clocks with optical detection
Authors: Chen Sifei , Liu Chang , Xu Shaohang , Li Yuanhao , Wang Jiale , Wang Yanhui , Liu Ying , Jiao Wenhai
Published: March 2022

In traditional cesium beam clocks, cesium atoms are deflected by strong inhomogeneous magnetic fields. The distribution of the detectable atoms, which is critical to the short-term frequency stability, is hard to describe with analytical functions. In this paper, we numerically analyze the beam optics performance of cesium beam tubes based on the magnetic-state-selected and fluorescence detection scheme. To accurately model the cesium beam tube, we apply the Monte Carlo sampling directly inside the collimator. The finite element method is also applied to model the magnetic field. Upon the high dimensional distribution space, two key parameters are selected as indicators of the short-term performance of the cesium beam tube, the effective velocity distribution, and the normalized density difference of atoms in |F=3,mF=0⟩ and |F=4,mF=0⟩. The influence of the configuration of the collimator is analyzed. Experiments are carried out with two manufactured beam tubes. The results show good agreement with the simulation model. We also discuss limitations of the simulation method when applied to designing cesium beam tubes.
Angular-dependent magnetoresistance in Cr1/3NbS2 single crystals
Authors: Li Xue , Li Zefang , Li Hang , Yao Yuan , Xi Xuekui , Lau Yong-Chang , Wang Wenhong
Published: March 2022

We present a comprehensive study of angular-dependent magnetoresistance (MR) in the layered chiral helimagnet Cr1/3NbS2 (CNS), which realizes a magnetic soliton lattice. It was found that, at temperatures below Curie temperature, CNS showed a negative magnetoresistance related to the emergence of a chiral soliton lattice state when a magnetic field was applied parallel to the ab-plane (H ‖ ab-plane). When the magnetic field was applied parallel to the c-axis (H ‖ c-axis), however, the negative MR disappeared and a positive MR appeared around zero field at low temperatures. Detailed analysis and modeling indicate that the positive MR is due to the weak anti-localization effect arising from the strong spin–orbit coupling of CNS.
Hyperbolic phonon polaritons with positive and negative phase velocities in suspended
α
-MoO3
Authors: Shen Jialiang , Zheng Zhiren , Dinh Thao , Wang Chuanyu , Chen Mingyuan , Chen Pengyu , Ma Qiong , Jarillo-Herrero Pablo , Kang Lixing , Dai Siyuan
Published: March 2022

Sample suspension is a valuable method to improve the mechanical, thermal, electronic, and optical properties of low-dimensional materials. In terms of confined light-matter waves—the polaritons, sample suspension can elongate the wavelength of polaritons with a positive phase velocity. Previous work demonstrates a wavelength elongation of ∼10% for hyperbolic phonon polaritons (HPPs) in uniaxial crystals of hexagonal boron nitride (hBN). In this work, we report the alteration of HPPs in biaxial α-phase molybdenum trioxide (α-MoO3) by sample suspension. Our combined infrared nano-imaging experiments and electromagnetic theory reveal a wavelength elongation > 60% and a propagation length increase > 140%, due to the simultaneous wavelength elongation and dissipation elimination in the suspended specimen. We have also examined HPPs in α-MoO3 with a negative phase velocity. The sample suspension shortens the HPP wavelength and simultaneously reduces the dissipation due to the unique permittivity tensor. The HPPs with improved figures of merits in the suspended specimen may be developed for nano-polaritonic circuits, biochemical sensing, emission engineering, and energy transfer.
Transient mixed-lubrication analysis of low-viscosity lubricated bearings under impact load with consideration of turbulence
Authors: Lv Fangrui , Shangguan Yanqin , Zou Donglin , Ji Aimin
Published: March 2022

For heavy-duty bearings with low-viscosity lubricant, asperities may contact near the minimum nominal film thickness, while turbulence may develop in the area with large film thickness. When bearings encounter transient impact or unsteady loads, the influence of turbulence and surface roughness is relatively complex. To investigate transient lubrication and dynamic characteristics of mixed-lubricated bearings with turbulent flow, a transient mixed-lubrication model considering turbulence is proposed in this paper. A transient generalized average Reynolds equation is derived based on the Ng-Pan turbulence model. The transient journal center positions are obtained by solving the journal's dynamic equation. The numerical procedure is established. Based on the proposed model, the effect of turbulence, surface roughness, and transient impact load direction as well as the magnitude on transient lubrication and dynamic characteristics of mixed-lubrication bearings is analyzed. The results show that turbulence increases the transient minimum nominal film thickness and may decrease the transient friction force in the mixed-lubrication regime. Surface roughness modifies the dynamic trajectory of the journal center and increases both the transient minimum nominal film thickness and the friction force in the mixed-lubrication regime. The impact load direction significantly affects transient characteristics of the bearing. An increase in the load-deflection angle destabilizes the bearing operation state.
Marangoni flow and surfactant transport in evaporating sessile droplets: A lattice Boltzmann study
Authors: Farhadi Jafar , Bazargan Vahid
Published: March 2022

The circulatory Marangoni flow can alter the contact line deposition in evaporating colloidal droplets with pinned contact line. Marangoni flow can be induced by surfactants or thermal effects. Although both cases have been exclusively investigated, the combined effect of surfactant-induced and thermal Marangoni flows is still unknown. The lattice Boltzmann method is utilized to simulate droplet evaporation and corresponding Marangoni flow. Five equations for hydrodynamics, interface capturing, vapor concentration, temperature field, and surfactant transport are intrinsically coupled with each other. They are simultaneously solved in the lattice Boltzmann framework. A geometrical method is proposed to pin the contact line at the triple point. First, evaporation-induced and thermal Marangoni flows are successfully captured. By incorporating surfactant-induced effects, interesting flow patterns are observed. Considering the combined effect of surfactant and temperature gradient, maximum surfactant concentration and maximum temperature (local minima for surface tension) are found at the top and the edge of the droplet, respectively. The maximum surface tension is consequently located between them, and double-circulation flow is observed. If the thermal effect is eliminated, surfactant local concentrations intermittently converge to steady values so that the edge concentration becomes higher than the apex concentration. Until reaching the steady state, there are two patterns that the flow alternates between: one in the direction of the thermal Marangoni flow and the other in the opposite direction.
Eulerian and Lagrangian transport by shallow-water breaking waves
Authors: Xie Zhihua , Lin Pengzhi
Published: March 2022

This study examines the mass and Lagrangian transport, kinematic and dynamic characteristics of shallow-water breaking waves, focusing on the wave breaking, and jet impingement processes. A multiphase Navier–Stokes flow model has been developed to track the origin and trajectory for the jet and the splash-up using both a geometric piece-wise linear interface calculation volume-of-fluid (PLIC-VOF) and the Lagrangian particle tracking approaches. The model is first validated both quantitatively and qualitatively against the experimental data for the plunging jet and the splash-up during wave breaking, in which a good agreement is obtained. The mass transport and the origin of the jet and splash-up are studied using the new multi-component PLIC-VOF approach, and the different regions in the interior of the wave are tracked in an Eulerian way. Both horizontal and vertical drifts for the interior and surface particles are shown using the Lagrangian particles. The location and origin of the plunging jet can be clearly seen from the simulations. Various wave steepness and beach slopes have been investigated for different types of breakers. Furthermore, the detailed jet impingement, velocity, pressure, vorticity, and turbulence fields during wave breaking are discussed and presented, providing more detailed flow fields to gain further insight into the plunging jet and splash-up in shallow-water breaking waves.
Coulomb drag and plasmonic effects in graphene field-effect transistors enable resonant terahertz detection
Authors: Ryzhii M. , Ryzhii V. , Otsuji T. , Mitin V. , Shur M. S.
Published: March 2022

We analyze the response of lateral n+-i-n-n+ graphene field-effect transistors (GFETs) to terahertz (THz) radiation. The nonlinearity due to the Coulomb drag of quasi-equilibrium carriers by injected ballistic carriers accompanied by plasmonic oscillations in a GFET channel enables a resonantly strong response. This effect can be used for effective resonant detection of THz radiation.
Preface: Non-equilibrium transport, interfaces, and mixing in plasmas
Authors: Abarzhi Snezhana I. , Gekelman Walter
Published: March 2022

Non-equilibrium transport, interfaces, and interfacial mixing play an important role in plasmas in high and low energy density regimes, at astrophysical and at atomic scales, and in nature and technology. Examples include the instabilities and interfacial mixing in supernovae and in inertial confinement fusion, the particle-field interactions in magnetic fusion and in imploding Z-pinches, the downdrafts in stellar interiors and in the planetary magneto-convection, magnetic flux ropes and structures in the solar corona, and plasma thrusters and nano-fabrication. This Special Topic exposes the state-of-the-art research on non-equilibrium transport, interfaces, and interfacial mixing in plasmas, including theory, experiment, and simulations. The works were presented at the invited mini-conference “Non-equilibrium Transport, Interfaces and Mixing in Plasmas” at the 2019 Annual Meeting of the Division of Plasma Physics of the American Physical Society.
After-hours presentations to community-based primary care in the Australian Capital Territory
Authors: Barnes Katelyn , Agostino Jason , Ceramidas Dagmar , Douglas Kirsty
Published: March 2022

Backgound This study describes patient characteristics and presentations to community-based primary care medical services in the after-hours period. Methods A cross-sectional survey completed by practitioners was voluntarily conducted over one weeknight and weekend in 2019 at 31 of 51 extended hours general practices (GP), three of three medical deputising services and three of three nurse-led walk-in clinics (WICs). Results Of 3371 community-based after-hours presentations, 934 consultation records were obtained (overall response: 28%). Emergency departments reported 524 triage code 4 and 5 patients within the study period. Problems managed in community-based after-hours services were most often rated as non-urgent (n = 482; 51.6%) and new (n = 606; 64.9%). The most common community-based after-hours presentations were diagnostic or disease related (e.g. infections or injury; n = 667; 59.5%). The most common body systems impacted were respiratory (n = 329; 29.6%), skin (n = 164; 16.4%) and general/unspecified (e.g. fever; n = 164; 16.4%). Community-based after-hours services reported different types of presentations, with medical deputising services reporting more urgent presentations, GPs reporting more procedural presentations and walk-in clinics reporting more skin-related issues (e.g. wound care). Conclusions Community-based after-hours medical services contribute significantly to after-hours medical care in the ACT. Patients are self-selecting community-based after-hours medical services appropriately based on problems managed by practitioners.
QES-Fire: a dynamically coupled fast-response wildfire model
Authors: Moody Matthew J. , Gibbs Jeremy A. , Krueger Steven , Mallia Derek , Pardyjak Eric R. , Kochanski Adam K. , Bailey Brian N. , Stoll Rob
Published: March 2022

A microscale wildfire model, QES-Fire, that dynamically couples the fire front to microscale winds was developed using a simplified physics rate of spread (ROS) model, a kinematic plume-rise model and a mass-consistent wind solver. The model is three-dimensional and couples fire heat fluxes to the wind field while being more computationally efficient than other coupled models. The plume-rise model calculates a potential velocity field scaled by the ROS model’s fire heat flux. Distinct plumes are merged using a multiscale plume-merging methodology that can efficiently represent complex fire fronts. The plume velocity is then superimposed on the ambient winds and the wind solver enforces conservation of mass on the combined field, which is then fed into the ROS model and iterated on until convergence. QES-Fire’s ability to represent plume rise is evaluated by comparing its results with those from an atmospheric large-eddy simulation (LES) model. Additionally, the model is compared with data from the FireFlux II field experiment. QES-Fire agrees well with both the LES and field experiment data, with domain-integrated buoyancy fluxes differing by less than 17% between LES and QES-Fire and less than a 10% difference in the ROS between QES-Fire and FireFlux II data.
Extension services can promote pasture restoration: Evidence from Brazil’s low carbon agriculture plan
Authors: Bragança Arthur , Newton Peter , Cohn Avery , Assunção Juliano , Camboim Cristiane , de Faveri Diego , Farinelli Barbara , Perego Viviana M.E. , Tavares Mateus , Resende Janei , de Medeiros Sidney , Searchinger Timothy D.
Published: March 2022

Significance

Livestock supply chains account for 14.5% of global greenhouse gases (GHG) emissions. There is a consensus that approaches that improve cattle productivity while enhancing carbon sequestration can contribute to the multiple goals of improving ranchers’ livelihoods and mitigating climate change. Identifying policies that simultaneously increase productivity and sequestration is therefore critical to promote sustainable growth in the livestock sector. This paper documents the impact of training and technical assistance on pasture restoration and productivity in Brazil. We found that providing technical assistance to previously trained producers promoted pasture restoration, induced farmers to use more inputs, helped them improve their practices, and increased productivity and carbon sequestration. These findings highlight the importance of providing customized information to ranchers to help them sustainably intensify.
Elucidation of the key role of Pt···Pt interactions in the directional self-assembly of platinum(II) complexes
Authors: Zheng Xiaoyan , Chan Michael Ho-Yeung , Chan Alan Kwun-Wa , Cao Siqin , Ng Maggie , Sheong Fu Kit , Li Chu , Goonetilleke Eshani Chrisana , Lam William Wai Yan , Lau Tai-Chu , Huang Xuhui , Yam Vivian Wing-Wah
Published: March 2022

Significance

Molecular self-assembly provides a bottom-up platform to design supramolecular functional materials, attracting numerous interests in material sciences. The utilization of platinum(II) complexes as building blocks of supramolecular assemblies opens up the unique noncovalent Pt···Pt interaction as one of the driving forces, imparting the supramolecular materials with rich spectroscopic features. However, the exact role of Pt···Pt interactions in molecular assembly remains elusive. The current study combines experimental and computational techniques to elucidate the role of Pt···Pt interactions in the self-assembly process of a representative amphiphilic platinum(II) complex. This work demonstrates the directional role of Pt···Pt interactions in assisting the molecular assembly in an anisotropic manner, achieving the formation of ordered self-assembled structures.
Recombination resolves the cost of horizontal gene transfer in experimental populations of
Helicobacter pylori
Authors: Nguyen An N. T. , Woods Laura C. , Gorrell Rebecca , Ramanan Shamitraa , Kwok Terry , McDonald Michael J.
Published: March 2022

Significance

Horizontal gene transfer (HGT)—the transfer of DNA between lineages—is responsible for a large proportion of the genetic variation that contributes to evolution in microbial populations. While HGT can bring beneficial genetic innovation, the transfer of DNA from other species or strains can also have deleterious effects. In this study, we evolve populations of the bacteria
Helicobacter pylori
and use DNA sequencing to identify over 40,000 genetic variants transferred by HGT. We measure the cost of many of these and find that both strongly beneficial mutations and deleterious mutations are genetic variants transferred by natural transformation. Importantly, we also show how recombination that separates linked beneficial and deleterious mutations resolves the cost of HGT.
Modulation of amyloid precursor protein cleavage by γ-secretase activating protein through phase separation
Authors: Jin Chen , Wang Jiaoni , Wang Yumeng , Jia Bojun , Guo Xuefei , Yang Guanghui , Xu Peng , Greengard Paul , Zhou Rui , Shi Yigong
Published: March 2022

Significance

γ-secretase activating protein (GSAP) has emerged as a key regulator of γ-secretase. In cells, GSAP exists primarily in the form of a 16-kDa fragment known as GSAP-16K. In this study, we report the finding that GSAP-16K undergoes phase separation in vitro and in cells. Importantly, the outcome of GSAP-16K phase separation directly regulates the protease activity of human γ-secretase. Through direct interaction with the substrate amyloid precursor protein–C-terminal 99-residue fragment, GSAP-16K in dilute phase favors the production of β-amyloid peptide 42 (Aβ42) but not Aβ40. These observations not only explain how GSAP activates γ-secretase but also identify their interaction as a target of potential therapeutic intervention.
Correspondences of matter field fluctuations in semiclassical and classical gravity in the decoherence limit
Authors: Satin Seema
Published: March 2022

A correspondence between fluctuations of non-minimally coupled scalar fields and that of an effective fluid with heat flux and anisotropic stresses, is shown. Though the correspondence between respective stress tensors of scalar fields and fluids is known and widely used in literature, the fluctuations in the two cases still await a formal correspondence and are open to investigation in all details. Using results obtained in the newly established theory of semiclassical stochastic gravity which focuses on the fluctuations of the quantum stress tensor, we show new relations in this regard. This development, apart from its relevance to the field-fluid correspondence, is expected to give insight to the mesoscopic phenomena for gravitating systems, and enable backreaction studies of the fluctuations on the perturbations of astrophysical objects. Such a development is aimed to enhance the perturbative analysis for cosmological spacetimes and astrophysical objects specifically in the decoherence limit. A kinetic theory, which can be based on stochastic fluctuations vs particle picture in curved spacetime may find useful insights from such correspondences in future work.
Light-enhanced gating effect at the interface of oxide heterostructure
Authors: Wadehra Neha , Tomar Ruchi , Yokoyama Yuichi , Yasui Akira , Ikenaga E , Wadati H , Maryenko Denis , Chakraverty S
Published: March 2022

In semiconducting materials, electrostatic gating and light illumination are widely used stimuli to tune the electronic properties of the system. Here, we show a significant enhancement of photoresponse at the conducting interface of LaVO3–SrTiO3 under the simultaneous application of light and negative gate bias voltage, in comparison to their individual application. On the other hand, the illuminated LaVO3-SrTiO3 interface does not show any enhancement, when a positive gate bias voltage is applied. Our x-ray diffractometer, Raman spectroscopy and photoemission measurements show that unlike the LaAlO3–SrTiO3 interface, migration of oxygen vacancies may not be the prime mechanism for the enhanced photoresponse. Rather, we suggest that the photoresponse of our system is intrinsic and this intrinsic mechanism is a complex interplay between band filling, electric field at the interface and modification of conducting channel width.
A label-free biomarkers detection platform relied on a bilayer long-wave infrared metamaterials BioNEMS sensor
Authors: Marvi Fahimeh , Jafari Kian
Published: March 2022

A novel approach based on optical Biological-Nano-Electro-Mechanical-Systems (BioNEMS) sensor is presented in this paper to provide highly sensitive and precise detection of biomolecules. The proposed BioNEMS sensor is relied on a bi-layer metamaterials structure, tuned by its wavelength. The presented biosensor consists of a BioNEMS membrane coated by Complementary Split Ring Resonators and an array of Split Ring Resonators cells on the substrate. While the immobilized bioreceptors adsorb the biomarkers (i.e. mRNA or protein), it causes a bending of the suspended membrane. This is due to the differential surface stress which is induced on the Nano-Electro-Mechanical-Systems structure. As a consequence, the coupling strength of two complementary metamaterial layers and thus the electromagnetic response of the biosensor are changed. Furthermore, the proposed device is designed and analyzed by numerical and analytical approaches in order to obtain its functional characteristics as follows: detection sensitivity of 21 967 nm/RIU, figure of merit of 327.8 RIU−1", mechanical sensitivity of 2.6 μm/Nm−1" and resonant frequency of 4.92 kHz. According to the obtained results, the functional characteristics of the proposed label-free biosensor show its high potential for highly sensitive and accurate molecule detections, disease diagnosis as well as drug delivery tests for Lab-On-Chip systems.
Synergistically segmenting choroidal layer and vessel using deep learning for choroid structure analysis
Authors: Zhu Lei , Li JunMeng , Zhu Ruilin , Meng Xiangxi , Rong Pei , Zhang Yibao , Jiang Zhe , Geng Mufeng , Qiu Bin , Rong Xin , Zhang Yadi , Gu Xiaopeng , Wang Yuwei , Zhang Zhiyue , Wang Jing , Yang Liu , Ren Qiushi , Lu Yanye
Published: March 2022

Objective. The choroid is the most vascularized structure in the human eye, whose layer structure and vessel distribution are both critical for the physiology of the retina, and disease pathogenesis of the eye. Although some works have used graph-based methods or convolutional neural networks to separate the choroid layer from the outer-choroid structure, few works focused on further distinguishing the inner-choroid structure, such as the choroid vessel and choroid stroma. Approach. Inspired by the multi-task learning strategy, in this paper, we propose a segmentation pipeline for choroid analysis which can separate the choroid layer from other structures and segment the choroid vessel synergistically. The key component of this pipeline is the proposed choroidal U-shape network (CUNet), which catches both correlation features and specific features between the choroid layer and the choroid vessel. Then pixel-wise classification is generated based on these two types of features to obtain choroid layer segmentation and vessel segmentation. Besides, the training process of CUNet is supervised by a proposed adaptive multi-task segmentation loss which adds a regularization term that is used to balance the performance of the two tasks. Main results. Experiments show the high performance (4% higher dice score) and less computational complexity (18.85 M lower size) of our proposed strategy. Significance. The high performance and generalization on both choroid layer and vessel segmentation indicate the clinical potential of our proposed pipeline.
Absolute OH density measurements in a CO2–H2O glow discharge by laser-induced fluorescence spectroscopy
Authors: Budde Maik , Martini Luca Matteo , Ceppelli Matteo , Quercetti Sara , Engeln Richard
Published: March 2022

Time-resolved absolute OH density measurements in a millisecond-pulsed DC glow discharge from carbon dioxide with water admixture, by laser-induced fluorescence (LIF) spectroscopy, are presented. For this purpose, a novel technique is suggested to calibrate the OH LIF setup by means of two-photon absorption LIF spectroscopy measurements on a CO-filled gas cell. OH densities in the order of 1 × 1018 m−3 are reported at a pressure of 6.67 mbar with a water admixture of 20% and a discharge current of 50 mA. Furthermore, the time evolution of the CO2 conversion is determined from collision energy transfer LIF and validated against the literature. The time-dependent rotational temperature of OH is obtained with LIF thermometry.
Cosmic ray ensembles as signatures of ultra-high energy photons interacting with the solar magnetic field
Authors: Dhital N. , Homola P. , Alvarez-Castillo D. , Góra D. , Wilczyński H. , Almeida Cheminant K. , Poncyljusz B. , Mędrala J. , Opiła G. , Bhatt A. , Łozowski B. , Bhatta G. , Bibrzycki Ł. , Bretz T. , Ćwikła A. , Del Peral L. , Duffy A.R. , Gupta A.C. , Hnatyk B. , Jagoda P. , Kasztelan M. , Kopański K. , Kovacs P. , Krupinski M. , Medvedev M. , Nazari V. , Niedźwiecki M. , Ostrogórski D. , Piekarczyk M. , Rodríguez Frías M.D. , Rzecki K. , Smelcerz K. , Smolek K. , Stasielak J. , Sushchov O. , Wibig T. , Wozniak K. , Zamora-Saa J. , Zimborás Z. , Tursunov A.
Published: March 2022

Propagation of ultra-high energy photons in the solar magnetosphere gives rise to cascades comprising thousands of photons.
We study the cascade development using Monte Carlo simulations and find that the photons in the cascades are
spatially extended over millions of kilometers on the plane distant from the Sun by 1 AU.
We estimate the chance of detection considering upper limits from current cosmic rays observatories in order to provide an optimistic estimate rate of 0.002 events per year from a chosen ring-shaped region around the Sun.
We compare results from simulations which use two models of the solar magnetic field, and show that although signatures of such cascades are different for
the models used, for practical detection purpose in the ground-based detectors, they are similar.
Formation of quaternary all-d-metal Heusler alloy by Co doping fcc type Ni2MnV and mechanical grinding induced B2-fcc transformation
Authors: Peng Lu , Zhang Qiangqiang , Wang Na , Xia Zhonghao , Zhang Yajiu , Wu Zhigang , Liu Enke , Liu Zhuhong
Published: March 2022

The structure of the all-d-metal alloy Ni50–x
Co
x
Mn25V25 (x = 0–50) is investigated by using theoretical and experimental methods. The first-principles calculations indicate that the most stable structure of the Ni2MnV alloy is face-centered cubic (fcc) type structure with ferrimagnetic state and the equilibrium lattice constant is 3.60 Å, which is in agreement with the experimental result. It is remarkable that replacing partial Ni with Co can turn the alloy from the fcc structure to the B2-type Heusler structure as Co content x > 37 by using the melting spinning method, implying that the d–d hybridization between Co/Mn elements and low-valent elements V stabilizes the Heusler structure. The Curie temperature T
C of all-d-metal Heuser alloy Ni50–x
Co
x
Mn25V25 (x > 37) increases almost linearly with the increase of Co due to that the interaction of Co–Mn is stronger than that of Ni–Mn. A magnetic transition from ferromagnetic state to weak magnetic state accompanying with grinding stress induced transformation from B2 to the dual-phase of B2 and fcc has been observed in these all-d-metal Heusler alloys. This phase transformation and magnetic change provide a guide to overcome the brittleness and make the all-d-metal Heusler alloy interesting in stress and magnetic driving structural transition.
Low-temperature heat transport of the zigzag spin-chain compound SrEr2O4
Authors: Chu Liguo , Guang Shuangkui , Zhou Haidong , Zhu Hong , Sun Xuefeng
Published: March 2022

Low-temperature thermal conductivity (κ), as well as the magnetic properties and specific heat, are studied for the frustrated zigzag spin-chain material SrEr2O4 by using single-crystal samples. The specific heat data indicate the long-range antiferromagnetic transition at ∼ 0.73 K and the existence of strong magnetic fluctuations. The magnetizations at very low temperatures for magnetic field along the c axis (spin chain direction) or the a axis reveal the field-induced magnetic transitions. The κ shows a strong dependence on magnetic field, applied along the c axis or the a axis, which is closely related to the magnetic transitions. Furthermore, high magnetic field induces a strong increase of κ. These results indicate that thermal conductivity along either the c axis or the a axis are mainly contributed by phonons, while magnetic excitations play a role of scattering phonons.
Superconductivity in Ce3PdIn11 single crystals – intrinsic phenomenon or parasitic effect?
Authors: Chajewski G , Gnida D , Das D , Kaczorowski D
Published: March 2022

Single crystals of the compound Ce3PdIn11 that belongs to a large family of superconducting cerium indides with the general formula Ce
m
T
n
In3m
+2n
(T stands for d-electron transition metal) were grown from indium flux and characterized by means of low-temperature specific heat and electrical resisitivity measurements. The collected data revealed significant sample-dependent divergence in their magnetic and superconducting properties which raises the question of whether these two cooperative phenomena are intrinsic properties of Ce3PdIn11.
Electronic structures and effective models in BaPtSb and BaPtAs with ordered honeycomb structures
Authors: Imai Yoshiki , Imazu Tsuyoshi , Goryo Jun
Published: March 2022

We investigate the low-energy electronic properties and construct the effective model Hamiltonians in the normal state for new materials BaPtSb and BaPtAs with ordered honeycomb structures. The preliminary experimental study suggested that the former compound may be a candidate of the time-reversal symmetry breaking superconductors. The low-energy electronic structures obtained from the first principles calculation mainly consist of Pt 5d and Sb/As 5p/4p orbitals, where there exist the strong hybridizations between both orbitals. We show that the main parts in the low-energy region including the Fermi surface are well described using renormalized 3 bands consisting of dominant Pt 2 bands and Sb/As 1 band. Our result provides a starting point for microscopic investigation in the superconducting states for the materials with the hexagonal structure.
Variation of the elliptical Fermi surface for a two-dimensional electron gas with anisotropic mass
Authors: Ciftja Orion
Published: March 2022

We consider a two-dimensional electron gas in the thermodynamic (bulk) limit. It is assumed that the system consists of fully spin-polarized (spinless) electrons with anisotropic mass. We study the variation of the shape of the expected elliptical Fermi surface as a function of the density of the system in presence of such form of internal anisotropy. To this effect, we calculate the energy of the system as well as the optimum ellipticity of the Fermi surface for two possible liquid states. One corresponds to the standard system with circular Fermi surface while the second one represents a liquid anisotropic phase with a tunable elliptical deformation of the Fermi surface that includes the state that minimizes the kinetic energy. The results obtained shed light on several possible scenarios that may arise in such a system. The competition between opposing tendencies of the kinetic energy and potential energy may lead to the stabilization of liquid phases where the optimal elliptical deformation of the Fermi surface is non-obvious and depends on the density as well as an array of other factors related to the specific values of various parameters that characterize the system.
Magnetic and vibrational properties of the covalent chain antiferromagnet RbFeS2
Authors: Kiiamov A , Seidov Z , Croitori D , Tsurkan V , Krug von Nidda H-A , Günther A , Tagirov L , Tayurskii D
Published: March 2022

Ternary rubidium-iron sulfide, RbFeS2, belongs to a family of quasi-one-dimensional compounds with the general chemical composition AFeCh
2 (where A – K, Rb, Cs, Tl; Ch – S, Se). Understanding the magnetic properties of these compounds is a challenge. The controversy concerning the spin-state of the iron ion needs to be resolved to build the proper model of magnetism. Single crystals of RbFeS2 were grown and characterized by powder x-ray diffraction. QD MPMS-5 SQUID magnetometry was used to measure the magnetic susceptibility, and specific heat was measured utilizing QD PPMS-9 setup. Above the transition to three-dimensional antiferromagnetic order at the Néel temperature of T
N = 188 K, the susceptibility exhibits unusual quasi-linear increase up to the highest measured temperature of 500 K. The specific heat was measured in the temperature range 1.8 – 300 K. Ab initio phonon dispersion and density-of-states calculations were performed by means of density functional theory (DFT), and the calculated lattice specific heat was subtracted from the measured one giving the magnetic contribution to the specific heat. Our results suggest that the features of the magnetic specific heat are general for the whole family of the covalent chain ternary iron chalcogenides of the AFeCh
2 structure and indicate an intermediate S = 3/2 spin state of the iron ion.
Majorana excitations in the anisotropic Kitaev model with an ordered-flux structure
Authors: Hashimoto Akihiro , Murakami Yuta , Koga Akihisa
Published: March 2022

We investigate the anisotropic S = 1/2 Kitaev model on the honeycomb lattice with the ordered-flux structure. By diagonalizing the Majorana Hamiltonian for the flux configuration, we find two distinct gapped quantum spin liquids. One of them is the gapped state realized in the large anisotropic case, where low energy properties are described by the toric code. On the other hand, when the system has small anisotropy, the other gapped quantum spin liquid is stabilized by the ordered-flux configuration. Since these two gapped quantum spin liquids are separated by the gapless region, these are not adiabatically connected to each other.
Low-temperature physical properties of new orthorhombic compounds RE2Au3Sn6 (RE = Ce, La)
Authors: Onishi K , Matsuoka E , Sugawara H , Sakurai T , Ohta H
Published: March 2022

We have prepared polycrystalline samples of RE2Au3Sn6 (RE = Ce, La) and investigated their magnetic, transport and thermal properties. We found that Ce2Au3Sn6 shows antiferromagnetic transition at T
N = 2.54 K, while La2Au3Sn6 shows no phase transition above 0.4 K. The electronic specific heat coefficient of Ce2Au3Sn6 is γ = 350 mJ Ce-mol K2, which indicates that Ce2Au3Sn6 is a heavy fermion compound. The magnetic entropy of Ce2Au3Sn6 at T
N is estimated to be 70% of Rln2, which can be attributed to the shielding of the magnetic moment by the Kondo effect.
Antiphase oscillations in the time-resolved spin structure factor of a photoexcited Mott insulator on a square lattice
Authors: Tohyama Takami , Shinjo Kazuya , Tsutsui Kenji
Published: March 2022

We investigate momentum-dependent transient spin dynamics after photoirradiation in a two-dimensional Mott insulator described by a half-filled Hubbard model on a square lattice by using a numerically exact-diagonalization technique. We find a temporal oscillation in the static spin structure factor of a

18

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periodic lattice. The oscillation exhibits an antiphase behavior between, for example, two orthogonal momentum directions parallel and perpendicular to the electric field of a pump pulse. The origin of the antiphase oscillation is attributed to a photoexcited wave function that has overlap with eigenstates producing the B
1g bimagnon Raman intensity. Observing such antiphase oscillations will be a big challenge for time-resolved resonant elastic x-ray scattering experiments.
Out of equilibrium charge transport in molecular electronic devices
Authors: Nava Andrea , Giuliano Domenico , Lepori Luca , Rossi Marco
Published: March 2022

Using the Lindblad equation approach, we study the nonequilibrium stationary state of a benzene ring connected to two reservoirs in the large bias regime, a prototype of a generic molecular electronic device. We show the emergence of an optimal working point (corresponding to a change in the monotonicity of the stationary current, as a function of the applied bias) and its robustness against chemical potential and bond disorder.
Properties of the spin-momentum locked state
Authors: Doria Mauro M. , Rodrigues Edinardo I. B.
Published: March 2022

Spin-momentum locking is becoming a cornerstone for the understanding and applications of novel condensed matter systems. Here we assume that it holds locally in position space and from it predict the existence of a local magnetic field. Although residual, this local magnetic field is important because it brings the topological stability that transforms particles into quasi-particles. The present approach shows that the Rashba term is already contained in the Schrödinger kinetic energy and a Dirac linear spectrum can be obtained without invoking a Dirac equation for the particles.
Field-angle dependence of thermal transport in Kitaev-Γ model
Authors: Koyama Shinnosuke , Nasu Joji
Published: March 2022

We investigate the magnetic field effect on the Kitaev model with the Γ-type interaction, which plays an essential role in understanding the magnetic properties of real materials. We examine the mean-field phase diagram and thermal Hall conductivity using the linear spin-wave theory. We find that the Γ interaction substantially changes the field-angle dependence of the thermal Hall conductivity and suppresses its magnitude. The suppression is caused by the enhancement of the low-energy magnon gap while increasing the Γ interaction.
Comparison of Arduino Nano and Due processors for time-based data acquisition for low-cost mobile radiation detection system
Authors: Lee J. , Lee M.S. , Jang M. , Lim J.-M.
Published: March 2022

Arduino is an open-source hardware and software platform
that consists of a single-board microcontroller (MCU). Arduino
offers low-cost and low-power operation, which allows the design of
a mobile battery-operated device and offers easy programming with a
wide range of compatible sensors. Hence, Arduino has recently been
widely used as an inexpensive solution to build educational and
evaluation tools. Here, we combined Arduino processors with
custom-developed time-based signal readout electronics for a
low-cost mobile radiation detection system; the system utilizes a
time-over-threshold technique that provides compact
electronics. Arduino processors were used for chip configuration,
serial communication, and real-time data acquisition. In this study,
we tested two commercial Arduino processors, Nano and Due, in
various signal environments and compared their performances. The
developed Arduino-based data acquisition system was combined with a
48 × 48 × 20 mm3 GAGG:Ce
(Gd3Al2Ga3O12:Ce) scintillation crystal and an
8 × 8 array of 6 × 6 mm2 SiPM. The developed
low-cost mobile gamma detection system achieved 9.35% energy
resolution at 662 keV and was able to acquire events up to 600 Hz
using an Arduino Nano.
Indo-Pacific warm pool present warming attribution and future projection constraint
Authors: Bai Wenrong , Liu Hailong , Lin Pengfei , Hu Shijian , Wang Fan
Published: March 2022

The Indo-Pacific warm pool (IPWP) has warmed and expanded substantially over the past decades, which has significantly affected the hydrological cycle and global climate system. It is unclear how the IPWP will change in the future under anthropogenic (ANT) forcing. Here, we quantify the human contribution to the observed IPWP warming/expansion and adjust the projected IPWP changes using an optimal fingerprinting method based on Coupled Model Intercomparison Project phase 6 (CMIP6) simulations. We find that more than 95% rapid warming and 85% expansion of the observed IPWP are detected and attributable to human influence. Furthermore, human activities affect IPWP warming through both greenhouse gases and ANT aerosols. The multiple model ensemble mean can capture the ANT warming trend and tends to underestimate the ANT warming trend. After using the observation constraint, the IPWP warming is projected to increase faster than that of the ensemble mean in the 21st Century, and the Indian Ocean warm pool is projected to expand more than previously expected. The rapid warming and expansion of IPWP over the rest of the 21st century will impact the climate system and the life of human beings.
Notch tensile and dry sliding wear studies on Mg-Nd-Gd-Zn alloy
Authors: Soundararajan R , Ali L Feroz , Srinidhi M S , Prabhu T Ram
Published: March 2022

This main purpose of the present research is to investigate the properties of wear and tensile in smooth and notch conditions of the heat-treated Mg-Nd-Gd-Zn alloy. The material applications such as complex helicopter gear box casing, piston and brake actuating components demands tensile data in notch conditions and wear characterizations. The alloy was characterized for microstructure, hardness, tensile properties in smooth and notch conditions and tribological properties such as wear resistance and friction coefficient. The microstructure examination revealed equiaxed grain structure with the size of about 42 μm. The XRD results confirms the presence of Mg3 (Nd) precipitates. Smooth and notched samples were evaluated to determine the effect of notch radii and ductile-brittle transition. Notched samples show 25.31% improvements in strength compared to the smooth sample with the marginal reduction in ductility (1.3%–1.8%). The fractography results for notched specimens exhibited cleavage, intergranular mode whereas the smooth specimens exhibited quasi cleavage, inter and transgranular modes. At 10N, the wear rate and friction coefficient change from 8.83 × 10–5 mm3 min−1 to 7.11 × 10–5 mm3 min−1 (24.2%) and to 0.29 and 0.26 (11.5%) respectively when the sliding velocity increases from 1 to 5 m s−1. Similarly, at 20N, the wear rate and friction coefficient change from 9.11 × 10–5 mm3 min−1 to 0.75 × 10–6 mm3 min−1 (12.7%) and 0.29 to 0.23 (26.1%) respectively when the sliding velocity increases from 1 to 5 m s−1. With the increase of load, plastic deformation is dominant controlling the wear rate. With the increase of sliding speed, oxidation is dominant controlling the wear rate and friction coefficient. Mixed modes of wear mechanisms such as abrasion, oxidation, delamination, third body assisted wear and melt wear were observed.