bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell death in skin function, inflammation, and disease
Authors: Anderton Holly , Alqudah Suhaib
Published: August 2022

Cell death is an essential process that plays a vital role in restoring and maintaining skin homeostasis. It supports recovery from acute injury and infection and regulates barrier function and immunity. Cell death can also provoke inflammatory responses. Loss of cell membrane integrity with lytic forms of cell death can incite inflammation due to the uncontrolled release of cell contents. Excessive or poorly regulated cell death is increasingly recognised as contributing to cutaneous inflammation. Therefore, drugs that inhibit cell death could be used therapeutically to treat certain inflammatory skin diseases. Programmes to develop such inhibitors are already underway. In this review, we outline the mechanisms of skin-associated cell death programmes; apoptosis, necroptosis, pyroptosis, NETosis, and the epidermal terminal differentiation programme, cornification. We discuss the evidence for their role in skin inflammation and disease and discuss therapeutic opportunities for targeting the cell death machinery.
Lombard Effect in Individuals With Nonphonotraumatic Vocal Hyperfunction: Impact on Acoustic, Aerodynamic, and Vocal Fold Vibratory Parameters
Authors: Castro Christian , Prado Pavel , Espinoza Víctor M. , Testart Alba , Marfull Daphne , Manriquez Rodrigo , Stepp Cara E. , Mehta Daryush D. , Hillman Robert E. , Zañartu Matías
Published: August 2022

Purpose:

This exploratory study aims to investigate variations in voice production in the presence of background noise (Lombard effect) in individuals with nonphonotraumatic vocal hyperfunction (NPVH) and individuals with typical voices using acoustic, aerodynamic, and vocal fold vibratory measures of phonatory function.

Method:

Nineteen participants with NPVH and 19 participants with typical voices produced simple vocal tasks in three sequential background conditions: baseline (in quiet), Lombard (in noise), and recovery (5 min after removing the noise). The Lombard condition consisted of speech-shaped noise at 80 dB SPL through audiometric headphones. Acoustic measures from a microphone, glottal aerodynamic parameters estimated from the oral airflow measured with a circumferentially vented pneumotachograph mask, and vocal fold vibratory parameters from high-speed videoendoscopy were analyzed.

Results:

During the Lombard condition, both groups exhibited a decrease in open quotient and increases in sound pressure level, peak-to-peak glottal airflow, maximum flow declination rate, and subglottal pressure. During the recovery condition, the acoustic and aerodynamic measures of individuals with typical voices returned to those of the baseline condition; however, recovery measures for individuals with NPVH did not return to baseline values.

Conclusions:

As expected, individuals with NPVH and participants with typical voices exhibited a Lombard effect in the presence of elevated background noise levels. During the recovery condition, individuals with NPVH did not return to their baseline state, pointing to a persistence of the Lombard effect after noise removal. This behavior could be related to disruptions in laryngeal motor control and may play a role in the etiology of NPVH.

Supplemental Material:

https://doi.org/10.23641/asha.20415600
Recursive recurrent neural network: A novel model for manipulator control with different levels of physical constraints
Authors: Li Zhan , Li Shuai
Published: August 2022

Manipulators actuate joints to let end effectors to perform precise path tracking tasks. Recurrent neural network which is described by dynamic models with parallel processing capability, is a powerful tool for kinematic control of manipulators. Due to physical limitations and actuation saturation of manipulator joints, the involvement of joint constraints for kinematic control of manipulators is essential and critical. However, current existing manipulator control methods based on recurrent neural networks mainly handle with limited levels of joint angular constraints, and to the best of our knowledge, methods for kinematic control of manipulators with higher order joint constraints based on recurrent neural networks are not yet reported. In this study, for the first time, a novel recursive recurrent network model is proposed to solve the kinematic control issue for manipulators with different levels of physical constraints, and the proposed recursive recurrent neural network can be formulated as a new manifold system to ensure control solution within all of the joint constraints in different orders. The theoretical analysis shows the stability and the purposed recursive recurrent neural network and its convergence to solution. Simulation results further demonstrate the effectiveness of the proposed method in end‐effector path tracking control under different levels of joint constraints based on the Kuka manipulator system. Comparisons with other methods such as the pseudoinverse‐based method and conventional recurrent neural network method substantiate the superiority of the proposed method.
Elastic temporal alignment for few‐shot action recognition
Authors: Pan Fei , Xu Chunlei , Zhang Hongjie , Guo Jie , Guo Yanwen
Published: August 2022

Few‐shot action recognition aims to learn a classification model with good generalisation ability when trained with only a few labelled videos. However, it is difficult to learn discriminative feature representations for videos in such a setting. The Elastic Temporal Alignment (ETA) for few‐shot action recognition is proposed. First, a convolutional neural network is employed to extract feature representations of video frames sparsely sampled from videos. In order to obtain the similarity of two videos, a temporal alignment estimation function is utilised to estimate the matching score between each pair of frames from the two videos through an elastic alignment mechanism. The analysis shows that when we judge whether two frames from respective videos are matched, multiple adjacent frames in the videos should be considered, so as to embody the temporal information. Thus, before feeding per‐frame feature vectors of videos into the temporal alignment estimation function, a temporal message passing function is leveraged to propagate the information of per‐frame features in the temporal domain. The method has been evaluated on four action recognition datasets, including Kinetics, Something‐Something V2, HMDB51, and UCF101. The experimental results verify the effectiveness of ETA and show its superiority over state‐of‐the‐art methods.
Optimal scheduling of Egyptian grid with pumped storage hydroelectric power plant
Authors: Abdelhady Rameen , Abdellatif Diaa
Published: August 2022

Egypt's national development plan aims at diversifying energy resources and expanding on renewable energy generation technologies. However, the Egyptian national grid needs energy‐storage components to stabilize its power supply when coupled with renewable energy due to the intermittent and random nature of them. The optimal power expansion plan has been reached using a production and costing software package electric generation expansion analysis system (EGEAS). Although pumped storage hydroelectric power plants (PSHPPs) have potential to be constructed in Attaqa Mountain, Egypt, it has not been considered in Egypt's optimal power expansion plan. This study proposes an optimal scheduling of Egypt's grid, adding PSHPP as a committed power plant. First, a mathematic formulation of Attaqa PSHPP is presented. Then, to reach the goal of economic dispatch, an optimal scheduling model of national grid is established with the consideration of both respective operation constraints and load requirements. The results of EGEAS simulation module showed that PSHPP operation for 20 years achieves a net fuel cost saving of 795 M$ as calculated from with and without PSHPP conditions at domestic subsidized fuel prices. More than double of this saving, 7778 M$, could be achieved if the net fuel cost savings are calculated at international fuel prices.
WLS algorithm for UAV navigation in satellite‐less environments
Authors: Santos Ricardo , Matos‐Carvalho J. P. , Tomic Slavisa , Beko Marko
Published: August 2022

This work addresses one of the major challenges in the field of Unmanned Aerial Vehicles (UAVs), which is related to UAV navigation in 3‐dimensional indoor environments. This topic is highly relevant due to limited‐to‐no availability of satellite signals that are usually the main sources used to govern the movement of UAVs in outdoor environments. Instead, the algorithm proposed in this work resorts to terrestrial radio measurements between the UAV and a set of stationary reference points to accomplish accurate navigation. The radio measurements are first exploited to give origin to range information that is used to calculate intersection points between a suitable subset of spheres, which serve as a coarse estimate of the UAV's position. From the intersection points, both azimuth and elevation angle estimates are obtained at each reference point. Finally, by taking advantage of estimated bearing information and applying simple geometry, the localisation problem is formulated according to the Weighted Least Squares (WLS) criterion and solved in closed form. The authors’ simulation results show good performance of the proposed approach, matching or even outperforming the state‐of‐the‐art methods in terms of localisation accuracy with significantly lower computational complexity.
Highly collimated microquasar jets as efficient cosmic-ray sources
Authors: Escobar G. J. , Pellizza L. J. , Romero G. E.
Published: August 2022

Context. Supernova remnants (SNRs) are currently believed to be the main sites of origin for Galactic cosmic rays. This scenario, however, fails to explain some of the features observed in the cosmic-ray spectrum. Microquasars have been proposed as additional candidates, as their non-thermal emission indicates the existence of efficient particle acceleration mechanisms in their jets. Only a few initial attempts have been made so far to quantify the contribution of microquasars to the Galactic cosmic-ray population. A promising scenario envisages the production of relativistic neutrons in the jets that decay outside the system, injecting relativistic protons to the surroundings. The first investigations of this scenario suggest that microquasars might stand as a fair alternative to cosmic-ray sources.

Aims. We aim to assess the role played by the degree of collimation of the jet on the cosmic-ray energetics in the neutron-carrier scenario, as well as the location and size of the emission region and the interactions of protons with photon fields. Our goal is to explain the Galactic component of the observed proton cosmic-ray spectrum at energies higher than ∼10 GeV and to relate the aforementioned jet properties with the power and spectral index of the produced cosmic rays.

Methods. Here, we improve upon previous analytical models of relativistic particle transport in microquasar jets by including prescriptions for the jet geometry and convection within it. We introduced the neutron component through catastrophic terms that couple the proton and neutron transport equations, then we computed the escape and decay of these neutrons. Finally, we followed the propagation of the decay products and obtained the proton cosmic-ray spectrum once the particles reached the interstellar medium.

Results. We find that collimated jets, with compact acceleration regions close to the jet base, are very efficient sources that could deliver a fraction of up to ∼0.01 of their relativistic proton luminosity into cosmic rays. Collimation is the most significant feature regarding efficiency: a well-collimated jet might be four orders of magnitude more efficient than a poorly collimated one. These sources produce a steep spectral index of ∼2.3 at energies up to ∼10 TeV.

Conclusions. Single microquasars may rival SNRs with respect to the power injected to the interstellar medium through cosmic rays. The main advantage of the former is the production of a steeper spectrum than the latter that is closer to what has been observed. The predictions of our model may be used to infer the total contribution of the population of Galactic microquasars to the cosmic ray population and, therefore, to quantitatively assess their significance as cosmic-ray sources.
Particle acceleration and radiation reaction in a strongly magnetised rotating dipole
Authors: Pétri J.
Published: August 2022

Context. Neutron stars are surrounded by ultra-relativistic particles efficiently accelerated by ultra-strong electromagnetic fields. These particles copiously emit high-energy photons through curvature, synchrotron and inverse Compton radiation. To date, however, no numerical simulations have been able to handle such extreme regimes of very high Lorentz factors and magnetic field strengths close to or even above the quantum critical limit of 4.4 × 109 T.

Aims. It is the purpose of this paper to study particle acceleration and radiation reaction damping in a rotating magnetic dipole with realistic field strengths of 105 T–1010 T typical of millisecond and young pulsars and of magnetars.

Methods. To this end, we implemented an exact analytical particle pusher including radiation reaction in the reduced Landau–Lifshitz approximation where the electromagnetic field is assumed constant in time and uniform in space during one time step integration. The position update is performed using a velocity Verlet method. We extensively tested our algorithm against time independent background electromagnetic fields like the electric drift in cross electric and magnetic fields and the magnetic drift and mirror motion in a dipole. Finally, we apply it to realistic neutron star environments.

Results. We investigated particle acceleration and the impact of radiation reaction for electrons, protons, and iron nuclei inserted around millisecond pulsars, young pulsars, and magnetars, in comparison to situations without radiation reaction. We found that the maximum Lorentz factor depends on the particle species, but only weakly on the neutron star type. Electrons reach energies up to γe ≈ 108 − 109, whereas protons reach energies up to γp ≈ 105 − 106 and iron up to γ ≈ 104 − 105. While protons and iron are not affected by radiation reaction, electrons are drastically decelerated, reducing their maximum Lorentz factor by four orders of magnitude. We also found that the radiation reaction limit trajectories agree quite well with the reduced Landau–Lifshitz approximation in almost all cases.
Tracking of magnetic helicity evolution in the inner heliosphere
Authors: Alberti T. , Narita Y. , Hadid L. Z. , Heyner D. , Milillo A. , Plainaki C. , Auster H.-U. , Richter I.
Published: August 2022

Context. Magnetic helicity is one of the invariants in ideal magnetohydrodynamics, and its spectral evolution has a substantial amount of information to reveal the mechanism that are behind turbulence in space and astrophysical plasmas.

Aims. The goal of our study is to observationally characterize the magnetic helicity evolution in the inner heliosphere by resolving the helicity transport in a scale-wise fashion in the spectral domain.

Methods. The evolution of the magnetic helicity spectrum in the inner heliosphere was tracked using a radial alignment event achieved by Parker Solar Probe at a distance of 0.17 astronomical units (AU) from the Sun and BepiColombo at 0.58 AU with a delay of about 3.5 days.

Results. The reduced magnetic helicity resolved in the frequency domain shows three main features: (1) a coherent major peak of a highly helical component at the lowest frequency at about 5 × 10−4 Hz, (2) a damping of helicity oscillation at the intermediate frequencies from 10−3 to 10−2 Hz when observed at 0.58 AU, and (3) a coherent nonhelical component in the ion-kinetic range at frequencies of about 0.1 − 1 Hz.

Conclusions. Though limited in the frequency range, the main message from this work is that the solar wind develops into turbulence by convecting large-scale helicity components on the one hand and creating and annihilating helical wave components on the other hand. Excitation of waves can overwrite the helicity profile in the inner heliosphere. By comparing this with the typical helicity spectra at a distance of 1 AU (that is, a randomly oscillating helicity sign in the intermediate frequency range up to about 1 Hz), the helicity evolution reaches a nearly asymptotic state at the Venus orbit (about 0.7 AU) and beyond.
Crossing Plasmopara viticola strains in controlled conditions to uncover the genomic bases of downy mildew resistance breakdown in grapevine
Authors: Dvorak E. , Mazet I. , Couture C. , Foulongne-Oriol M. , Delmotte F.
Published: August 2022

The biotrophic oomycete Plasmopara viticola is the causal agent of downy mildew, one of the major grapevine diseases. We report here a successful strategy to cross compatible strains of this pathogen and obtain a large viable progeny. We used this method to study the offspring between two P. viticola strains able to overcome two major grapevine resistance factors (Rpv3, Rpv10). Thanks to the genomic resources now available, we will genotype this progeny to build an unprecedented linkage map and uncover the genomic bases of grapevine resistance breakdown displayed by P. viticola virulent strains.
Les approches One Health pour faire face aux émergences: un nécessaire dialogue État-sciences-sociétés
Authors: Olive Marie-Marie , Angot Jean-Luc , Binot Aurélie , Desclaux Alice , Dombreval Loïc , Lefrançois Thierry , Lury Antoine , Paul Mathilde , Peyre Marisa , Simard Frédéric , Weinbach Jérôme , Roger François
Published: August 2022

En mars 2021, Montpellier Université d’excellence (MUSE) et Agropolis International ont réuni des décideurs, acteurs opérationnels, représentants d’organisations internationales et scientifiques pour partager leurs expériences des approches intégrées en santé dans le cadre du concept One Health. Ces échanges intersectoriels fructueux ont croisé les points de vue et ont pointé les obstacles et les enjeux de la mise en œuvre concrète de ces approches. Les participants ont abouti à des propositions pour rendre plus efficace cette mise en œuvre et faire face aux menaces sanitaires émergentes et aux futures pandémies : coconstruire des projets intégrés avec tous les acteurs concernés (citoyens, décideurs politiques, chercheurs, services locaux) ; développer des méthodes d’évaluation de leurs impacts ; former les acteurs ; institutionnaliser et coordonner les actions du niveau local au niveau mondial.
Orthographe et compétence linguistique : ce que dit le e de crie
Authors: Vogüé Sarah de
Published: August 2022

On s’intéresse à une confusion à l’écrit entre formes homophones correspondant à un nom et un verbe mais s’opposant par un simple e final. On montre que les personnes susceptibles de faire l’erreur maîtrisent pourtant la différence nom/verbe, comme aussi les propriétés des e muets et des consonnes dites latentes. On revisite le statut morphologique de ce e et on présente un dispositif pédagogique destiné aux jeunes adultes, qui utilise les ressources du numérique pour intégrer ces différents résultats.
Le savoir orthographique : du collectivement construit à l’individuellement approprié ?
Authors: Lavieu-Gwozdz Belinda , Pagnier Thierry
Published: August 2022

L’objet de notre recherche est de comprendre la manière dont les élèves se saisissent de manières différenciées des situations didactiques qui leurs sont proposées dans le cadre de l’orthographe, notamment les interactions. La question de recherche qui guide notre protocole de recherche est la suivante : le savoir orthographique, collectivement construit peut-il être individuellement mobilisé, ressaisi par les élèves lorsqu’ils se trouvent confrontés à une forme à orthographier ?
Des effets des dispositifs et des pratiques : retour sur la notiond’effetsà partir d’une première synthèse des résultats produits par le programme de recherche TAO,Twictéepour apprendre l’orthographe
Authors: Delarue-Breton Catherine
Published: August 2022

Le programme de recherche TAO a évalué des effets d’un dispositif collaboratif d’enseignement de l’orthographe, Twictée, sur les apprentissages des élèves et sur le développement professionnel des enseignants. À partir d’une première synthèse des résultats de ce programme, on revient sur la notion d’effets du dispositif, qui dépendent des pratiques pédagogiques et langagières qui l’accompagnent.
Numérique et apprentissages : des décalages de perceptions entre élèves et enseignants
Authors: Fenoglio Prisca , Crinon Jacques , Ferone Georges
Published: August 2022

« Twictée » vise à développer les compétences orthographiques des élèves de l’école et du collège, grâce à l’échange, entre classes distantes, de phrases dictées et de corrections justifiées, au moyen du réseau Twitter. Cet article interroge les convergences et divergences de perceptions du numérique qu’ont des enseignants et des élèves participant à ce dispositif. Par l’analyse de contenu thématique de trois séries d’entretiens de 19 enseignants de cycle 3 et de deux séries d’entretiens de 45 de leurs élèves (dans cinq classes), nous constatons des écarts de représentations à propos du numérique et des difficultés, pour la plupart des élèves, mais surtout pour les plus faibles, à concevoir ce qui leur est demandé.
Audiovisual intervention alleviates anxiety of patients during PET/CT imaging
Authors: Abouzian Safae , Camacho Valle , Sabaté Aida , Stefaneli Patricia , Sizova Marina , Gich Ignasi , López-Mora Diego , Duch Joan , Fernández Alejandro , Estorch Montserrat , Carrió Ignasi , Flotats Albert
Published: August 2022

Aim to assess if the use of an audiovisual intervention in the uptake room and/or in the scanning room, could help to reduce anxiety during [18F]FDG PET/CT imaging.

Methods We prospectively studied 120 patients referred for [18F]FDG PET/CT imaging. Patients were allocated in 4 groups of 30 patients depending on the use of the audiovisual intervention: (1) no audiovisual intervention; (2) audiovisual intervention only in the uptake room; (3) audiovisual intervention only in the scanning room; (4) audiovisual intervention in the uptake and the scanning rooms. In order to measure the anxiety levels of the patients before and after the scan, all patients answered the State-Trait Anxiety Inventory (STAI).

Results The anxiety status across typical situations on a daily basis (STAI-T) of the 4 groups of patients was comparable with no significant differences. The mean State Anxiety (STAI-S) sum-score at prescan and postscan among groups was: (1) 17.5±8.7 vs. 17.3±8.6, p=0.834; (2) 17.4±10.5 vs. 15.8±9.6, p=0.110; (3) 17.5±11.7 vs. 15.1±9.8, p= 0.013; (4) 17.4±9.7 vs. 14.9±8.1, p= 0.009. The percentage of patients with reduction of the STAI-S score among groups 1–4 was 17%, 47%, 50%, and 66%, respectively. The variation of the percentage of patients with lower scores after intervention among groups was statistically significant (p<0.001).

Conclusion Audiovisual intervention decreases anxiety levels of patients referred for PET/CT imaging. The results of our study support a beneficial effect of the audiovisual intervention and its potential to alleviate the anxiety of oncological patients who undergo a PET/CT scan.
Multidisciplinary Postoperative Care Pathway to Reduce Readmissions following Endoscopic Transsphenoidal Pituitary Surgery: Improving Quality of Patient Care
Authors: Ghiam Michael K. , Ali Ibrahim A. , Dable Cortney L. , Ayala Alejandro R. , Kargi Atil Y. , Komotar Ricardo J. , Levine Corinna G. , Sargi Zoukaa
Published: August 2022

Background Thirty-day unplanned readmission following endoscopic transsphenoidal pituitary surgery (ETPS) occurs in up to 14% of patients. Delayed hyponatremia is one of the most common causes, accounting for 30% of readmissions and often occurs within 1 week of surgery. The authors' prior retrospective review identified endocrinology follow-up as protective factor.

Objectives Implementation of a multidisciplinary postoperative care (POC) pathway: (1) to reduce 30-day hospital readmissions following ETPS and (2) improve inpatient and outpatient coordination of care with endocrinologist.

Methods This study is a single institution temporal cohort study of patients prior to (control cohort) and after implementation of the POC pathway (intervention cohort). The POC pathway utilized postdischarge 1 to 1.5 L/d fluid restriction, postoperative days 5 to 7 serum sodium, and endocrinology follow-up within 1 week of discharge to stratify patients into tiered hyponatremia regimens.

Results A total of 542 patients were included in the study, 409 (75%) in the control cohort and 133 (25%) in the intervention cohort. All-cause readmission was significantly reduced following implementation of the POC pathway (14 vs. 6%, p = 0.015). Coordination with endocrinologist significantly increased in the inpatient (96 vs. 83%, p < 0.001) and outpatient (77 vs. 68%, p = 0.042) settings. Patients who were not in the POC pathway had the highest risk of readmission (odds ratio: 2.5; 95% confidence interval: 1.1–5.5).

Conclusion A multidisciplinary POC pathway incorporating endocrinologist in conjunction with postdischarge weight-based fluid restriction and postoperative serum sodium levels can safely be used to reduce 30-day readmissions following ETPS.
The Awakening of a Sleeping Beauty: The ortho Photocycloaddition in the Total Synthesis of Protoilludane- and Prezizaene-Type ­Sesquiterpenes
Authors: Bach Thorsten , Gilbert Audrey
Published: August 2022

Photochemical cascade (domino) reactions provide a unique opportunity for the construction of complex molecular architectures. Specifically, an intramolecular ortho photocycloaddition of 7-(alkenyloxy)-indanones triggers a sequence of consecutive reactions that can lead in a single operation to the complete skeleton of two important classes of sesquiterpenes: protoilludanes and prezizaenes. In the former case, two transformations follow the initial photocycloaddition, while in the latter case, there are three consecutive transformations, two of which are initiated by a photon. Remarkably, the reaction cascades proceed with exquisite diastereoselectivity, generating three (protoilludane) or five (prezizaene) stereogenic centers with defined relative configurations.

1 Introduction

2 First Encounter and Initial Studies

3 Protoilludane-Type Sesquiterpenes

4 Prezizaene-Type Sesquiterpenes

5 Enantioselectivity

6 Perspective and Summary
Convergent neutral gas injection using supersonic gas puffing (SSGP) method for propellant feeding system in RF electric propulsion
Authors: Furukawa Takeru , Ishigami Yuichi , Kuwahara Daisuke , Miyazawa Jyunichi , Shinohara Shunjiro
Published: August 2022

A convergent gas feeding method is proposed to alleviate neutral gas depletion near the central plasma region in typical electrodeless radio-frequency (RF)/helicon plasma thrusters. To achieve further performance improvement, the SuperSonic Gas Puffing (SSGP) system is one of the methods that is expected to overcome the above-mentioned depletion and the density limit. This study discovered that the spatiotemporal profiles of the neutral pressure and the estimated gas diffusion angle vary depending on the SSGP gas feeding condition, i.e., the nozzle size, filling pressure, and the valve opening time. Convergent gas feeding is successfully conducted using the SSGP method in a vacuum. As a preliminary study, high-density plasma is also obtained in the vicinity of the gas injection region using the developed SSGP system. The effects of the gas feeding position and an external divergent magnetic field on the plasma density are investigated. A suitable gas feeding position/region exists for plasma generation using the RF/helicon plasma thruster.
Miniature laser powder bed fusion system for in situ synchrotron x-ray micro-computed tomography experiments at the European Synchrotron Radiation Facility
Authors: Lhuissier Pierre , Hébrard Louis , Bataillon Xavier , Lapouge Pierre , Coste Frédéric , Peyre Patrice , Boller Elodie , Blandin Jean-Jacques , Salvo Luc , Martin Guilhem
Published: August 2022

We describe our miniature laser powder bed fusion (L-PBF) system for in situ synchrotron x-ray micro-computed tomography (XCT) at the European Synchrotron Radiation Facility. This replicator was designed to extend the characterization of L-PBF to 3D. This instrument fills in a technical gap because the existing replicators were mostly designed to shed light on the dynamic mechanisms involved in molten pool formation but, therefore, suffered from a lack of 3D information. Technical details regarding the setup and beamline integration are given. Experimental validations via post-mortem XCT scans and in situ scans acquired during experiments conducted at the BM05 beamline of the European Synchrotron Radiation Facility are provided. Based on a few illustrative examples, we show that such a replicator opens the path to collect key 3D information that to date could not be available. Our miniature instrument complements the other replicators developed in the world by other research groups that enable operando x-ray imaging (radiography) and operando x-ray diffraction.
Theoretical prediction of Curie temperature in two-dimensional ferromagnetic monolayer
Authors: Xue Yufei , Shen Zhong , Wu Zebin , Song Changsheng
Published: August 2022

Theoretical prediction of Curie temperature (TC) is of vital importance for designing spintronic devices in two-dimensional (2D) ferromagnetic materials. Herein, based on the extensive investigation of Monte Carlo simulations, we summarize and propose an improved method to estimate TC more precisely, which includes the different contributions of multiple near-neighbor interactions. Using monolayer CrI3 as an example, the trends of TC with biaxial strain are investigated via Monte Carlo simulations, mean-field formulas, and our method. Our method is not only accurate and convenient to predict the TC in 2D ferromagnetic honeycomb lattice CrI3, but it can also be extended to predicting the TC of other 2D lattices. Our work paves the way to accelerate the prediction and discovery of novel 2D ferromagnets for spintronic applications.
A compound cantilever beam piezoelectric harvester based on wind energy excitation
Authors: Zhang Zheng , He Lipeng , Hu Renhui , Hu Dianbin , Zhou Jianwen , Cheng Guangming
Published: August 2022

In this paper, a compound cantilever beam based piezoelectric energy harvester (CCBPH) is proposed. This piezoelectric energy harvester uses vibrations caused by vortex excitation behind the winding fluid to harvest wind energy. In particular, this structure uses vortex excitation formed behind a vertically suspended cylindrical winding fluid to cause the vibration of the cylindrical winding fluid, which then indirectly excites the piezoelectric element. The CCBPH consists of a fixed support, a cantilever beam, magnet-1 and magnet-2, a support beam, two piezoelectric units-PVDF (polyvinylidene fluoride), a compound cantilever beam, and a cylindrical winding fluid. We investigated the parameters affecting the structure and verify the effectiveness of the energy harvester through the design of the structure, simulation analysis, and experiments. The experimental results show that the CCBPH can obtain the maximum output voltage from the energy harvester at a wind speed of 18 m/s. The maximum output power was achieved with an external load resistance of 2000 kΩ. By comparison, it is found that the maximum output power is 0.095 mW when the distance between two magnets is 20 mm and the mass ratio is 1:2 for copper.
Statistical neural network (SNN) for predicting signal-to-noise ratio (SNR) from static parameters and its validation in 16-bit, 125-MSPS analog-to-digital converters (ADCs)
Authors: Hou Linjie , Liu Yvtao , Xie Weikun , Dai Zhijian , Yang Wanyv , Zhao Yijiu
Published: August 2022

In the analog-to-digital converter (ADC) test process, the static and dynamic performance parameters are the most important, and the tests for these parameters account for the bulk of the ADC test cost. These two types of parameters follow certain relationships, which are incorporated into the ADC test to reduce the cost. In this paper, we focus on the signal-to-noise ratio (SNR), a key indicator of the dynamic performances of ADCs. A statistical neural network (SNN) with two hidden layers was constructed to predict the SNR from the feature variables, which were extracted from the static parameters. A 16-bit, 125-MSPS ADC was used to evaluate the proposed prediction model. Compared to the measured SNR obtained by traditional fast Fourier transform based test methods, the predicted value had a mean average error of only 0.75 dB. In addition, the Shapley additive explanations interpreter was adopted to analyze the feature dependences of the SNN model, and the results demonstrated that the deterioration of the integral nonlinearity-curve-related features could significantly decrease the SNR, which is consistent with previous research results. The reported results demonstrated that, at the cost of a slight loss of accuracy, the proposed SNN can significantly reduce the test complexity, avoid dynamic parameter measurements, and reduce the total test time by about 4%.
High sensitivity gas pressure sensor based on different inner diameter quartz capillary cascading and Vernier effect
Authors: Ye Wenhao , Jiang Chao , Guo Xiaoshan , Chen Hailin , Wang Yuan , Zhu Xiping , Sun Simei , Liu Changning
Published: August 2022

In this paper, a highly sensitive optical fiber gas pressure sensor is proposed and experimentally verified. The sensor is composed of two Fabry–Pérot (F-P) cavities, and two F-P cavities are fabricated by a single-mode fiber and two quartz capillaries with different inner diameters splicing. Among them, the small inner diameter capillary is used as a gas channel connecting the large inner diameter capillary and the external environment. The manufacturing process of the sensor only involves capillary cleaver and splicing and does not involve other complex manufacturing technologies. By correctly adjusting the length of the two quartz capillaries, when the free spectral range of the two F–P cavities is very close, the optical Vernier effect will be observed and used as a sensitive probe for detecting gas pressure. The experimental results show that, in the pressure range of 0–0.8 MPa, the gas pressure sensitivity of the sensor reaches −81.73 nm/MPa with a linearity of 99.7%, and the temperature cross-sensitivity is only 1.82 kPa/°C. Due to its easy manufacture, high sensitivity, compact structure, and small volume, the sensor has become one of the preferred structures for large-scale use in the field of gas sensing.
Energetic electron scattering by kinetic Alfvén waves at strong magnetic field gradients of dipolarization front
Authors: Shen Yangyang , Artemyev Anton , Vasko Ivan , Zhang Xiao-Jia , Angelopoulos Vassilis , An Xin , Runov Andrei
Published: August 2022

Energetic electron scattering and precipitation from the Earth's plasma sheet to the ionosphere is an important contributor to magnetosphere–ionosphere coupling. In this study, we investigate the role of one of the most intense wave emissions, kinetic Alfvén waves (KAWs), in energetic electron scattering. We have evaluated the effect of KAWs on energetic electrons within a curved magnetic field configuration exhibiting sharp cross field gradients. The magnetic field in Earth's magnetotail plasma sheet with an embedded dipolarization front is used as a working example. Taking into account electron bounce motion and perpendicular guiding-center drifts, we have shown that electrons with energies of tens to hundreds of keV can be scattered by KAWs in pitch angle and momentum through Doppler-shifted Landau resonance near the magnetic equator. The bounce-averaged pitch-angle diffusion coefficients for near-loss-cone (∼2°) electrons are on the order of 10–7–10–6 rad2/s for a characteristic KAW amplitude of 1 mV/m and approach the strong diffusion limit of ∼10–4 rad2/s for amplitudes of greater than 10 mV/m. These results suggest that under such ambient conditions, KAWs can pitch-angle scatter energetic electron population into the loss cone. In Earth's plasma sheet, this scattering is, thus, very likely to cause significant precipitation during active times. The diffusion coefficients of energetic electrons at large pitch angles (∼45°–∼80°) are more than two orders of magnitude larger than those of electrons near the loss cone, suggesting that KAWs contribute to isotropization of anisotropic electrons due to adiabatic heating should they drift into the vicinity of the magnetic field gradient.
Selective electronic excitations in nearly half-metallic Heusler alloy NiFeMnSn—A Raman spectroscopic study
Authors: Bera Kousik , Mukherjee Supratik , Mukadam M. , Mondal Subrata , Firoz M. K. , Vaitheeswaran G. , Roy Anushree , Yusuf S. M.
Published: August 2022

Half-metallic ferromagnetic full Heusler alloy NiFeMnSn is a promising material in spintronic device fabrication as it carries high spin polarization and high Curie temperature (Tc = 405 K). Understanding electronic excitations in a spin-polarized band structure is essential for the further use of this material in spin-based devices and to optimize the spin-dependent electronic structure in related compounds. In this Letter, we report electronic Raman scattering of NiFeMnSn with spectral signatures at a higher wavenumber than expected from the calculated phonon modes of the system. Temperature-dependent Raman spectroscopy demonstrates a non-monotonic behavior of the Raman shift with temperature across Tc. The orbital resolved electronic density of states and electronic band structure for both spin channels of the system, as obtained from the first principles density functional theory calculations, suggest that the observed Raman signatures originate from the Fe d orbital and its splitting due to the crystal field near the Fermi level. Furthermore, a strong magnetic field dependence of the spectral profile is observed. The study not only exhibits electronic Raman scattering in a Heusler alloy compound, which was unexplored to date, but also establishes Raman scattering as a promising probe to study the orbital-resolved partial density of states in the band structure near the Fermi level of a Heusler alloy.
Extension of natural reaction orbital approach to multiconfigurational wavefunctions
Authors: Ebisawa Shuichi , Tsutsumi Takuro , Taketsugu Tetsuya
Published: August 2022

Recently, we proposed a new orbital analysis method, natural reaction orbital (NRO), which automatically extracts orbital pairs that characterize electron transfer in reaction processes by singular value decomposition of the first-order orbital response matrix to the nuclear coordinate displacements [Ebisawa et al., Phys. Chem. Chem. Phys. 24, 3532 (2022)]. NRO analysis along the intrinsic reaction coordinate (IRC) for several typical chemical reactions demonstrated that electron transfer occurs mainly in the vicinity of transition states and in regions where the energy profile along the IRC shows shoulder features, allowing the reaction mechanism to be explained in terms of electron motion. However, its application has been limited to single configuration theories such as Hartree–Fock theory and density functional theory. In this work, the concept of NRO is extended to multiconfigurational wavefunctions and formulated as the multiconfiguration NRO (MC-NRO). The MC-NRO method is applicable to various types of electronic structure theories, including multiconfigurational theory and linear response theory, and is expected to be a practical tool for extracting the essential qualitative features of a broad range of chemical reactions, including covalent bond dissociation and chemical reactions in electronically excited states. In this paper, we calculate the IRC for five basic chemical reaction processes at the level of the complete active space self-consistent field theory and discuss the phenomenon of electron transfer by performing MC-NRO analysis along each IRC. Finally, issues and future prospects of the MC-NRO method are discussed.
Self-consistent formation and steady-state characterization of trapped high-energy electron clouds in the presence of a neutral gas background
Authors: Le Bars G. , Hogge J.-Ph. , Loizu J. , Alberti S. , Romano F. , Cerfon A.
Published: August 2022

This study considers the self-consistent formation and dynamics of electron clouds interacting with a background neutral gas through elastic and inelastic (ionization) collisions in coaxial geometries similar to gyrotron electron guns. These clouds remain axially trapped as the result of crossed magnetic field lines and electric equipotential lines creating potential wells similar to those used in Penning traps. Contrary to standard Penning traps, in this study, we consider a strong externally applied radial electric field which is of the same order as that of the space-charge field. In particular, the combination of coaxial geometry, strong radial electric fields, and electron collisions with the residual neutral gas (RNG) present in the chamber induce non-negligible radial particle transport and ionization. In this paper, the dynamics of the cloud density and currents resulting from electron–neutral collisions are studied using a 2D3V particle-in-cell code. Simulation results and parametric scans are hereby presented. Finally, a fluid model is derived to explain and predict the cloud peak density and peak radial current depending on the externally applied electric and magnetic fields, and on the RNG pressure.
Mainlobe maintenance for FDA-MIMO radar
Authors: Xu YanJie , Wang ChunYang , Gong Jian , Zhao YingJian , Zhou ChangLin
Published: August 2022

During radar detection, the adaptive beamforming technique needs to create nulls to resist the interference. When the interference appears within the mainlobe, the main detection beam will become distorted. To solve this problem, a new method for the covariance matrix reconstruction is proposed for the mainlobe maintenance problem, and a worst-case performance optimization (WCPO) algorithm with enhanced waveform robustness is obtained. Its integration is performed over a known region without the target information to obtain the improved covariance matrix, which is then brought into the convex optimization equation to solve for the weight vector. Simulation results show that the output signal-to-noise ratio of this algorithm is higher than that of the conventional WCPO algorithm with a robust beam for the same signal-to-noise ratio. It can also effectively eliminate the primary lobe offset and secondary lobe elevation problems.
High-frequency limit of spectroscopy
Authors: Nazarov Vladimir U. , Baer Roi
Published: August 2022

We consider an arbitrary quantum mechanical system, initially in its ground-state, exposed to a time-dependent electromagnetic pulse with a carrier frequency ω0 and a slowly varying envelope of finite duration. By working out a solution to the time-dependent Schrödinger equation in the high- ω0 limit, we find that, to the leading order in [Formula: see text], a perfect self-cancellation of the system’s linear response occurs as the pulse switches off. Surprisingly, the system’s observables are, nonetheless, describable in terms of a combination of its linear density response function and nonlinear functions of the electric field. An analysis of a jellium slab and jellium sphere models reveals a very high surface sensitivity of the considered setup, producing a richer excitation spectrum than accessible within the conventional linear response regime. On this basis, we propose a new spectroscopic technique, which we provisionally name the Nonlinear High-Frequency Pulsed Spectroscopy (NLHFPS). Combining the advantages of the extraordinary surface sensitivity, the absence of constraints by the traditional dipole selection rules, and the clarity of theoretical interpretation utilizing the linear response time-dependent density functional theory, NLHFPS has a potential to evolve into a powerful characterization method for nanoscience and nanotechnology.
A new potential energy surface and rovibrational spectra of the CO–CO2 complex: Dependence on the antisymmetric stretching vibration of CO2
Authors: Peng Yang , Zhu Fangfang , Zhu Hua
Published: August 2022

We present a new ab initio five-dimensional potential energy surface for the CO–CO2 complex containing the Q3 normal mode for the ν3 asymmetric stretching vibration of the CO2 unit. The potential was calculated by the supermolecular approach at the explicitly correlated coupled cluster [CCSD (T)-F12a] level with aug-cc-pVTZ basis set plus midpoint bond functions. Two vibrationally averaged four-dimensional potentials for CO–CO2 with CO2 at the ground and ν3 excited states were generated by the integration of the five-dimensional potential over the Q3 intramolecular coordinate. Each potential displays a T-shaped global minimum with the C end in the CO unit pointing toward the C atom in the CO2 unit and a T-shaped local minimum but with the CO monomer rotated by 180°. The rovibrational bound states and energy levels for the CO–CO2 dimer were obtained employing the radial discrete variable representation/angular finite basis representation method in conjunction with the Lanczos algorithm. The vibrational ground and some lower excited states for CO–CO2 are localized around the global minimum because of the higher potential barriers. The band origin is blueshifted by 0.2089 cm−1 for CO–CO2 in the CO2 ν3 range, which is consistent with the experimental result of 0.211 cm−1. The geared bending vibrational frequencies for CO–CO2 are 24.7101 and 24.5549 cm−1 at the ground and ν3 excited states of CO2, respectively. The predicted rovibrational frequencies, as well as spectral constants, coincide with the available observations, and these parameters show that the CO–CO2 complex is a nearly prolate asymmetric rotor.
High kinetic inductance NbTiN superconducting transmission line resonators in the very thin film limit
Authors: Bretz-Sullivan Terence M. , Lewis Rupert M. , Lima-Sharma Ana L. , Lidsky David , Smyth Christopher M. , Harris C. Thomas , Venuti Michael , Eley Serena , Lu Tzu-Ming
Published: August 2022

We examine the DC and radio frequency (RF) response of superconducting transmission line resonators comprised of very thin NbTiN films, <12 nm in thickness, in the high-temperature limit, where the photon energy is less than the thermal energy. The resonant frequencies of these superconducting resonators show a significant nonlinear response as a function of RF input power, which can approach a frequency shift of Δf=−0.15% in a −20 dB span in the thinnest film. The strong nonlinear response allows these very thin film resonators to serve as high kinetic inductance parametric amplifiers.