bluuebunny/crossref_metadata_2025 huggingface dataset:
Secondary electron emission and vacuum electronics
Authors: Yater J. E.
Published: February 2023

Secondary electron emission serves as the foundation for a broad range of vacuum electronic devices and instrumentation, from particle detectors and multipliers to high-power amplifiers. While secondary yields of at least 3–4 are required in practical applications, the emitter stability can be compromised by surface dynamics during operation. As a result, the range of practical emitter materials is limited. The development of new emitter materials with high yield and robust operation would advance the state-of-the-art and enable new device concepts and applications. In this Perspective article, I first present an analysis of the secondary emission process, with an emphasis on the influence of material properties. From this analysis, ultra-wide bandgap (UWBG) semiconductors and oxides emerge as superior emitter candidates owing to exceptional surface and transport properties that enable a very high yield of low-energy electrons with narrow energy spread. Importantly, exciting advances are being made in the development of promising UWBG semiconductors such as diamond, cubic boron nitride (c-BN), and aluminum nitride (AlN), as well as UWBG oxides with improved conductivity and crystallinity. These advances are enabled by epitaxial growth techniques that provide control over the electronic properties critical to secondary electron emission, while advanced theoretical tools provide guidance to optimize these properties. Presently, H-terminated diamond offers the greatest opportunity because of its thermally stable negative electron affinity (NEA). In fact, an electron amplifier under development exploits the high yield from this NEA surface, while more robust NEA diamond surfaces are demonstrated with potential for high yields in a range of device applications. Although c-BN and AlN are less mature, they provide opportunities to design novel heterostructures that can enhance the yield further.
Investigation of neutron imaging applications using fine-grained nuclear emulsion
Authors: Muneem Abdul , Yoshida Junya , Ekawa Hiroyuki , Hino Masahiro , Hirota Katsuya , Ichikawa Go , Kasagi Ayumi , Kitaguchi Masaaki , Muto Naoto , Mishima Kenji , Nabi Jameel-Un , Nakagawa Manami , Naganawa Naotaka , Saito Takehiko R.
Published: February 2023

Neutron imaging is a nondestructive inspection technique that has a wide range of applications. One of the important aspects of neutron imaging is achieving a micrometer-scale spatial resolution. The development of a high-resolution neutron detector is a challenging task. As one potential solution to this task, we investigate whether neutron detectors based on fine-grained nuclear emulsions are suitable for high-resolution neutron imaging applications. High track density is necessary to improve the quality of neutron imaging. However, the available track analysis methods are difficult to apply under high track density conditions. Simulated images are used to determine the required track density for neutron imaging. A track density of the order of 104 tracks per 100×100μm2 is sufficient to utilize neutron detectors for imaging applications. Contrast resolution was also investigated for image datasets with various track densities and neutron transmission rates. Moreover, experiments were performed for the neutron imaging of gadolinium-based gratings with known geometries. The grating structures were successfully resolved. The calculated 1σ 10%–90% edge response using the grayscale optical images of the grating slit with a periodic structure of 9 μm was 0.945±0.004 μm.
Comparative study of electrical properties of semi-insulating GaN substrates grown by hydride vapor phase epitaxy and doped with Fe, C, or Mn
Authors: Tanaka Daiki , Iso Kenji , Suda Jun
Published: February 2023

The electrical properties of semi-insulating GaN substrates doped with iron (Fe), carbon (C), or manganese (Mn) grown by hydride vapor phase epitaxy are presented. Hall effect measurements were performed at temperatures ranging from 300 to 800 K. At all of the investigated temperatures, the Mn-doped samples exhibited the highest resistivity. The Fe-doped samples showed n-type conduction, whereas the C-doped samples and the Mn-doped sample with a Mn concentration of 1 × 1019 cm−3 showed p-type conduction. A detailed analysis of the temperature dependence of the carrier concentration showed that all of the impurities formed acceptor levels at EC −(0.59–0.61) eV for Fe, at EV +(0.90–1.07) eV for C, and at EV +1.55 eV for Mn. The Mn-doped sample with a Mn concentration of 8 × 1017 cm−3 showed a negative Hall coefficient (suggesting n-type conduction) at high temperatures, contradicting the formation of acceptor levels by Mn. We successfully explained the negative value by considering the conduction of both holes and electrons with different mobilities. On the basis of the results, we calculated the relationship between the resistivity and doping concentration for each dopant. The calculations indicated that the highest resistivity can be realized in Mn-doped GaN with an optimized doping concentration (depending on the residual donor concentration). All of the dopants can effectively realize high resistivity at room temperature. Mn is an effective dopant for attaining high resistivity, especially at high temperatures (e.g., 800 K).
Effect of turbulence modulation caused by thread structure on coaxial air-blast atomization
Authors: Wang Yufan , Yao Tianliang , Zhao Hui , Li Weifeng , Xu Jianliang , Liu Haifeng
Published: February 2023

This study aims at investigating the influence of turbulence modulation caused by a thread structure on coaxial air-blast atomization by means of high-speed flow visualizations and droplet particle size techniques. The medium in the central channel of an atomizer is water while the annular channel is airflow. The results show that the thread structure added to the inner surface of an annular channel plays an important role in atomization effect. The generated liquid ligaments on the jet present more structures, which grow shorter and breakup faster than that without thread. To compare the difference in jet breakup length and droplet diameter caused by the thread structure, we establish a new breakup length model and then use the ratio of structure factors to describe the change in the droplet diameter. The results in this experiment confirm the improvement of atomization performance brought by optimization design of the thread structure.
Modeling for understanding of coronavirus disease-2019 (COVID-19) spread and design of an isolation room in a hospital
Authors: Wu Xiaofei , Abubakar-Waziri Hisham , Fang Fangxin , Dilliway Claire , Wu Pin , Li Jinxi , Yao Runming , Bhavsar Pankaj , Kumar Prashant , Pain Christopher C. , Chung Kian Fan
Published: February 2023

We have modeled the transmission of coronavirus 2019 in the isolation room of a patient suffering from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the Royal Brompton Hospital in London. An adaptive mesh computational fluid dynamics model was used for simulation of three-dimensional spatial distribution of SARS-CoV-2 in the room. The modeling set-up is based on data collected in the room during the patient stay. Many numerical experiments have been carried out to provide an optimal design layout of the overall isolation room. Our focus has been on (1) the location of the air extractor and filtration rates, (2) the bed location of the patient, and (3) consideration of the health and safety of the staff working in the area.
Fick–Jacobs description and first passage dynamics for diffusion in a channel under stochastic resetting
Authors: Jain Siddharth , Boyer Denis , Pal Arnab , Dagdug Leonardo
Published: February 2023

The transport of particles through channels is of paramount importance in physics, chemistry, and surface science due to its broad real world applications. Much insight can be gained by observing the transition paths of a particle through a channel and collecting statistics on the lifetimes in the channel or the escape probabilities from the channel. In this paper, we consider the diffusive transport through a narrow conical channel of a Brownian particle subject to intermittent dynamics, namely, stochastic resetting. As such, resetting brings the particle back to a desired location from where it resumes its diffusive phase. To this end, we extend the Fick–Jacobs theory of channel-facilitated diffusive transport to resetting-induced transport. Exact expressions for the conditional mean first passage times, escape probabilities, and the total average lifetime in the channel are obtained, and their behavior as a function of the resetting rate is highlighted. It is shown that resetting can expedite the transport through the channel—rigorous constraints for such conditions are then illustrated. Furthermore, we observe that a carefully chosen resetting rate can render the average lifetime of the particle inside the channel minimal. Interestingly, the optimal rate undergoes continuous and discontinuous transitions as some relevant system parameters are varied. The validity of our one-dimensional analysis and the corresponding theoretical predictions is supported by three-dimensional Brownian dynamics simulations. We thus believe that resetting can be useful to facilitate particle transport across biological membranes—a phenomenon that can spearhead further theoretical and experimental studies.
Influence of the environment on the infrared spectrum of alanine: An effective mode analysis
Authors: Bowles Jessica , Jähnigen Sascha , Vuilleumier Rodolphe , Calvo Florent , Clavaguéra Carine , Agostini Federica
Published: February 2023

The vibrational spectrum of the alanine amino acid was computationally determined in the infrared range 1000–2000 cm−1, under various environments encompassing the gas, hydrated, and crystalline phases, by means of classical molecular dynamics trajectories, carried out with the Atomic Multipole Optimized Energetics for Biomolecular Simulation polarizable force field. An effective mode analysis was performed, in which the spectra are optimally decomposed into different absorption bands arising from well-defined internal modes. In the gas phase, this analysis allows us to unravel the significant differences between the spectra obtained for the neutral and zwitterionic forms of alanine. In condensed phases, the method provides invaluable insight into the molecular origins of the vibrational bands and further shows that peaks with similar positions can be traced to rather different molecular motions.
The interactions of the elliptical instability and convection
Authors: de Vries Nils B. , Barker Adrian J. , Hollerbach Rainer
Published: February 2023

Elliptical instability is an instability of elliptical streamlines, which can be excited by large-scale tidal flows in rotating fluid bodies and excites inertial waves if the dimensionless tidal amplitude (ε) is sufficiently large. It operates in convection zones, but its interactions with turbulent convection have not been studied in this context. We perform an extensive suite of Cartesian hydrodynamical simulations in wide boxes to explore the interactions of elliptical instability and Rayleigh–Bénard convection. We find that geostrophic vortices generated by the elliptical instability dominate the flow, with energies far exceeding those of the inertial waves. Furthermore, we find that the elliptical instability can operate with convection, but it is suppressed for sufficiently strong convection, primarily by convectively driven large-scale vortices. We examine the flow in Fourier space, allowing us to determine the energetically dominant frequencies and wavenumbers. We find that power primarily concentrates in geostrophic vortices, in convectively unstable wavenumbers, and along the inertial wave dispersion relation, even in non-elliptically deformed convective flows. Examining linear growth rates on a convective background, we find that convective large-scale vortices suppress the elliptical instability in the same way as the geostrophic vortices created by the elliptical instability itself. Finally, convective motions act as an effective viscosity on large-scale tidal flows, providing a sustained energy transfer (scaling as ε2). Furthermore, we find that the energy transfer resulting from bursts of elliptical instability, when it operates, is consistent with the ε3 scaling found in prior work.
Emergence of allostery through reorganization of protein residue network architecture
Authors: Samanta Riya , Sanghvi Neel , Beckett Dorothy , Matysiak Silvina
Published: February 2023

Despite more than a century of study, consensus on the molecular basis of allostery remains elusive. A comparison of allosteric and non-allosteric members of a protein family can shed light on this important regulatory mechanism, and the bacterial biotin protein ligases, which catalyze post-translational biotin addition, provide an ideal system for such comparison. While the Class I bacterial ligases only function as enzymes, the bifunctional Class II ligases use the same structural architecture for an additional transcription repression function. This additional function depends on allosterically activated homodimerization followed by DNA binding. In this work, we used experimental, computational network, and bioinformatics analyses to uncover distinguishing features that enable allostery in the Class II biotin protein ligases. Experimental studies of the Class II Escherichia coli protein indicate that catalytic site residues are critical for both catalysis and allostery. However, allostery also depends on amino acids that are more broadly distributed throughout the protein structure. Energy-based community network analysis of representative Class I and Class II proteins reveals distinct residue community architectures, interactions among the communities, and responses of the network to allosteric effector binding. Bioinformatics mutual information analyses of multiple sequence alignments indicate distinct networks of coevolving residues in the two protein families. The results support the role of divergent local residue community network structures both inside and outside of the conserved enzyme active site combined with distinct inter-community interactions as keys to the emergence of allostery in the Class II biotin protein ligases.
Microbubble collapse near a fiber: Broken symmetry conditions and a planar jet formation
Authors: Mur Jaka , Agrež Vid , Zevnik Jure , Petkovšek Rok , Dular Matevž
Published: February 2023

The collapse of microbubbles near a fiber is an example often encountered in water treatment situations and cavitation fibrillation processes. However, due to the broken symmetry conditions, this process has not been studied in detail experimentally or numerically, making it difficult to precisely measure or simulate the rapid bubble evolution during collapse. In this work, we present a novel experimental method, allowing for precisely repeatable cavitation events observation, combined with numerical simulations offering insight into pressure and velocity fields distribution developments in time. Both experimental and numerical works focused on small distances between the bubble and the fiber, where the physical interaction between subjects is the strongest. Four different bubble offsets were considered within the scope of this work, and very good agreement of numerical simulations with experiments was found in all cases. Two modes of bubble collapse were identified, leading to mushroom-shaped bubbles at positions closest to the fiber and a pear-shaped bubble at the farthest position. It is noteworthy that in all four cases, a planar jet formation toward the fiber was observed. The formed jet initially assumes an elongated shape, whereas its stability depends on the mode of bubble collapse. Numerical analysis of the planar jet as the defining feature of the collapse defined lower bounds for the actual values of peak jet velocities, ranging between 250 and 330 m/s, and the resulting impact pressures, which range from 100to 500 MPa.
Collision integrals for N(4S)–N(4S), N(4S)–N(2D), and N(4S)–N(2P) interactions
Authors: Ding Zi , Qin Zhi , Liu Linhua
Published: February 2023

Collision integrals for the scattering of nitrogen (N) atoms are essential to model transport properties of air plasmas, which can be highly dependent on the species involved. At high temperatures, N atoms may exist in their excited states. Therefore, collision integrals for N atoms are computed at the temperature range of 500–50 000 K, in which the interactions between the excited [N(2D) and N(2P)] atoms and ground N(4S) atom are considered. The interaction between the excited N(2P) atom and ground N(4S) atom is considered for the first time. A comparison of the collision integrals from our combined-hyperbolic-inverse-power-representation (CHIPR) potential energy function with those obtained using other analytical potential energy functions in the literature is given. The results show that the trend of potential energy curves (PECs) in dissociated asymptotic and short-range regions has an important effect on the collision integrals. These regions are difficult to cover in experiments. Here we seek the state-of-the-art ab initio methods for a theoretical guideline to compute the PECs of N2, which are then modeled by the CHIPR function. PECs of some low-lying states are also refined by available experimental spectroscopic data. Overall, our collision integrals are reliable.
Scaled charges for ions: An improvement but not the final word for modeling electrolytes in water
Authors: Blazquez S. , Conde M. M. , Vega C.
Published: February 2023

In this work, we discuss the use of scaled charges when developing force fields for NaCl in water. We shall develop force fields for Na+ and Cl− using the following values for the scaled charge (in electron units): ±0.75, ±0.80, ±0.85, and ±0.92 along with the TIP4P/2005 model of water (for which previous force fields were proposed for q = ±0.85 and q = ±1). The properties considered in this work are densities, structural properties, transport properties, surface tension, freezing point depression, and maximum in density. All the developed models were able to describe quite well the experimental values of the densities. Structural properties were well described by models with charges equal to or larger than ±0.85, surface tension by the charge ±0.92, maximum in density by the charge ±0.85, and transport properties by the charge ±0.75. The use of a scaled charge of ±0.75 is able to reproduce with high accuracy the viscosities and diffusion coefficients of NaCl solutions for the first time. We have also considered the case of KCl in water, and the results obtained were fully consistent with those of NaCl. There is no value of the scaled charge able to reproduce all the properties considered in this work. Although certainly scaled charges are not the final word in the development of force fields for electrolytes in water, its use may have some practical advantages. Certain values of the scaled charge could be the best option when the interest is to describe certain experimental properties.
High-throughput ab initio reaction mechanism exploration in the cloud with automated multi-reference validation
Authors: Unsleber Jan P. , Liu Hongbin , Talirz Leopold , Weymuth Thomas , Mörchen Maximilian , Grofe Adam , Wecker Dave , Stein Christopher J. , Panyala Ajay , Peng Bo , Kowalski Karol , Troyer Matthias , Reiher Markus
Published: February 2023

Quantum chemical calculations on atomistic systems have evolved into a standard approach to studying molecular matter. These calculations often involve a significant amount of manual input and expertise, although most of this effort could be automated, which would alleviate the need for expertise in software and hardware accessibility. Here, we present the AutoRXN workflow, an automated workflow for exploratory high-throughput electronic structure calculations of molecular systems, in which (i) density functional theory methods are exploited to deliver minimum and transition-state structures and corresponding energies and properties, (ii) coupled cluster calculations are then launched for optimized structures to provide more accurate energy and property estimates, and (iii) multi-reference diagnostics are evaluated to back check the coupled cluster results and subject them to automated multi-configurational calculations for potential multi-configurational cases. All calculations are carried out in a cloud environment and support massive computational campaigns. Key features of all components of the AutoRXN workflow are autonomy, stability, and minimum operator interference. We highlight the AutoRXN workflow with the example of an autonomous reaction mechanism exploration of the mode of action of a homogeneous catalyst for the asymmetric reduction of ketones.
Effects of incoming free-stream turbulence on the flow dynamics of a square finite wall-mounted cylinder
Authors: Chen Guang , Li Xiaobai , Xue Rudai , He Kan , Wang Hanfeng , Liang Xifeng
Published: February 2023

This study attempts to describe associated fluid dynamics of a square finite wall-mounted cylinder (FWMC) immersed within free-stream turbulent flow characterized by different turbulence intensities and integral length scales. An improved delayed detached eddy simulation method is adopted to numerically reproduce the fully developed turbulent flow fields. The results reveal that both the turbulence intensities and integral length scales have a significant effect on the separated shear layers, base pressure, and associated aerodynamic forces of the cylinder. Constrained streamlines along with critical point techniques are employed to further illustrate the influence of parameters of interest on a time-averaged flow pattern, including horseshoe vortex, surface flow, and wake topology. Distribution of second-order statistics within the wake region shows a shorter longitudinal length of the reversed flow region and enhanced vortex strength when background turbulence intensity increases. The time-dependent interaction between background turbulence and separated flow around the square FWMC is illustrated based on the phase difference between pressure of opposing side faces and the evolution of the reverse-flow region. In the end, the spectral proper orthogonal decomposition technique is employed to further investigate the effects of incoming flow turbulence on characteristics of the free-end shear flow and Von Kármán vortex shedding in the wake.
The “violin model”: Looking at community networks for dynamic allostery
Authors: Madan Lalima K. , Welsh Colin L. , Kornev Alexandr P. , Taylor Susan S.
Published: February 2023

Allosteric regulation of proteins continues to be an engaging research topic for the scientific community. Models describing allosteric communication have evolved from focusing on conformation-based descriptors of protein structural changes to appreciating the role of internal protein dynamics as a mediator of allostery. Here, we explain a “violin model” for allostery as a contemporary method for approaching the Cooper–Dryden model based on redistribution of protein thermal fluctuations. Based on graph theory, the violin model makes use of community network analysis to functionally cluster correlated protein motions obtained from molecular dynamics simulations. This Review provides the theory and workflow of the methodology and explains the application of violin model to unravel the workings of protein kinase A.
Solving response expressions in the ADC/ISR framework
Authors: Scheurer Maximilian , Papapostolou Antonia , Fransson Thomas , Norman Patrick , Dreuw Andreas , Rehn Dirk R.
Published: February 2023

We present an implementation for the calculation of molecular response properties using the algebraic-diagrammatic construction (ADC)/intermediate state representation approach. For the second-order ADC model [ADC(2)], a memory-efficient ansatz avoiding the storage of double excitation amplitudes is investigated. We compare the performance of different numerical algorithms for the solution of the underlying response equations for ADC(2) and show that our approach also strongly improves the convergence behavior for the investigated algorithms compared with the standard implementation. All routines are implemented in an open-source Python library.
Experiment on liquid film flow and heat transfer of laminar liquid jet impacting on cylindrical surface
Authors: Wu Shuang-Ying , Zhou Shi-Yao , Xiao Lan , Chen Li , Chen Zhi-Li
Published: February 2023

Laminar liquid jet impact has good heat transfer performance with low impact stress on targets. In order to explore the liquid film flow and heat transfer under laminar liquid jet impact on a cylindrical surface, first the flow of a liquid film was analyzed visually; then, the local convective heat transfer characteristics on the cylindrical surface at different impact heights and outlet Reynolds numbers (Re) were obtained by a combination of direct measurement and numerical simulation, followed by a comparative analysis with continuous droplets impacting on the cylindrical surface. The results show that according to flow behavior of the liquid film along the circumferential direction, circumference can be classified into stagnation, thin liquid film, hydraulic jump, stable flow path, and dripping regions. Local convective heat transfer coefficient first drops and subsequently increases marginally along the circumferential direction, while decreasing monotonically along the axial direction. The effect of impact height and outlet Re on local convective heat transfer coefficient is manifested mainly in stagnation, thin liquid film, and hydraulic jump regions. For outlet Re = 984, as impact height rises to a certain degree, there are apparent enhancements of the liquid film perturbation and convective heat transfer performance. Finally, the local Nusselt number correlations in different circumferential regions were proposed.
Reconstructing the self-luminous image of a flame in a supersonic combustor based on residual network reconstruction algorithm
Authors: Deng Xue , Guo Mingming , Tian Ye , Li Linjing , Le Jialing , Zhang Hua , Zhong Fuyu
Published: February 2023

The reconstruction of the self-luminous image of a flame through deep learning can inform research on the characteristics of combustion of a scramjet. In this study, the authors propose a residual network model based on the channel and spatial attention mechanisms to reconstruct the self-luminous image of a flame from schlieren images of the flow field of a scramjet. We compare the reconstruction-related performance of single-path and dual-path models under different conditions. The channel and spatial attention mechanisms enable the model to focus on important feature-related information, and the residual connection prevents gradient disappearance to improve the capability of the model for generalization. The proposed method was tested through a supersonic combustion experiment in a ground wind tunnel under different equivalence ratios, and data on the flow field of the combustion chamber and the evolution of the flame were recorded as a dataset. A number of experiments as well as subjective and objective analyses were subsequently carried out on this dataset. The results show that the effect of reconstruction is consistent with the original image of the flame, and the geometric characteristics of the flame are accurately reconstructed.
Relationship between coherent Reynolds shear stress and large-scale vortical structures
Authors: Chen J. G. , Antonia R. A. , Zhou Y.
Published: February 2023

An equation that relates the principal derivative of the Reynolds shear stress and large-scale vorticity fluxes is developed and validated using experimental data in a cylinder near wake. When large-scale vortices prevail, the Reynolds shear stress associated with the coherent motion is a good approximation to the conventional Reynolds shear stress. The latter is essentially determined by the imbalance between the dynamic pressure arising from the streamwise non-homogeneity caused by large-scale vortical structures and the lateral coherent vorticity flux.
Assessment of three-body dispersion models against coupled-cluster benchmarks for crystalline benzene, carbon dioxide, and triazine
Authors: Xie Yi , Glick Zachary L. , Sherrill C. David
Published: February 2023

To study the contribution of three-body dispersion to crystal lattice energies, we compute the three-body contributions to the lattice energies for crystalline benzene, carbon dioxide, and triazine using various computational methods. We show that these contributions converge quickly as the intermolecular distances between the monomers grow. In particular, the smallest value among the three pairwise intermonomer closest-contact distances, Rmin, shows a strong correlation with the three-body contribution to the lattice energy, and, here, the largest of the closest-contact distances, Rmax, serves as a cutoff criterion to limit the number of trimers to be considered. We considered all trimers up to Rmax=15Å. The trimers with Rmin<4Å contribute 90.4%, 90.6%, and 93.9% of the total three-body contributions for crystalline benzene, carbon dioxide, and triazine, respectively, for the coupled-cluster singles, doubles, and perturbative triples [CCSD(T)] method. For trimers with Rmin>4Å, the second-order Møller–Plesset perturbation theory (MP2) supplemented with the Axilrod–Teller–Muto (ATM) three-body dispersion correction reproduces the CCSD(T) values for the cumulative three-body contributions with errors of less than 0.1 kJ mol−1. Moreover, three-body contributions are converged within 0.15 kJ mol−1 by Rmax=10Å. From these results, it appears that in molecular crystals where dispersion dominates the three-body contribution to the lattice energy, the trimers with Rmin>4Å can be computed with the MP2+ATM method to reduce the computational cost, and those with Rmax>10Å appear to be basically negligible.
A novel method for measuring residual flux density of the single-phase transformer core based on phase difference
Authors: Ren Yuzhan , Wang Youhua , Liu Chengcheng , Wu Shipu
Published: February 2023

A serious inrush current may occur when a power transformer is re-energized, which will cause many adverse effects on power equipment and the power grid. The corresponding potential hazards can be reduced if the existing residual flux density (Br) can be accurately measured. Combined with the field-circuit coupling analysis method, a novel method for measuring the Br based on the phase difference between the applied AC voltage and resulting transient current is proposed in this paper. When the same AC voltage is applied to the transformer winding, the Br affects the resulting transient current. The phase difference between the applied voltage and the resulting current can be calculated by the cross-correlation technique. Based on the finite element method (FEM), the empirical formula for the quantitative measurement of Br in the transformer core is determined. Finally, an experimental study is performed on the square core of single-phase transformers. The experimental results reveal that the proposed measurement method is with high accuracy.
The 3-D vector hysteresis model of SMC materials based on the SAE and play operator
Authors: Ma Yangyang , Li Yongjian , Dou Yu , Yue Mingyu , Yang Ming
Published: February 2023

The hysteresis modeling of ferromagnetic materials in electrical equipment is one of the basic theoretical studies in the field of electrical engineering. In this paper, a 3-D vector hysteresis model is proposed based on Stacked Auto-Encoder (SAE) model and hysteresis operator space theory. Multiple 3-D vector Play hysteresis operators are used to construct an hysteresis operator space to create the high-dimensional operator data. By the operator space, the nonlinear hysteresis relationship in the hysteresis data is transformed into a nonlinear mapping between the operator data and the output of the model. And the SAE model is used to characterize this nonlinear mapping. In the training of the SAE model, training set is composed of operator data and magnetic field strength data. The structure of the vector hysteresis model is determined by taking the output of the operator space as the input of the SAE model. The simulation results show that the model can effectively describe the nonlinear characteristics and anisotropic of the Soft Magnetic Composite under 3-D vector excitation. In addition, this model has certain generalization ability.
High-precision 3D reconstruction of multiple magnetic targets based on center weighting method
Authors: Lan Tian , Qiu Jing , Li Yuquan , Sun Hexuan , Huang Shuanglong
Published: February 2023

A high-precision three-dimensional reconstruction method of multiple magnetic targets is studied in this paper. The inversion space is divided into cubic grid cells, and various complex shapes of magnetic targets are simulated by the combination of grid cells. The forward calculation of the magnetic gradient tensor in the spatial domain is performed. Then, the correlation imaging method is used to calculate cross correlation between the observed magnetic gradient tensor and the theoretical magnetic gradient at each grid cell tensor due to a magnetic dipole. The spatial distribution and center position of magnetic targets are preliminarily estimated by the resultant correlation coefficients, and use them to construct the center weighting function as a constraint to the inversion equations. The solution is completed by using the conjugate gradient method to estimate the magnetic susceptibility of each grid cell, and the 3D outline of the magnetic target is depicted by using the visualization technique. The experimental results show that the proposed method can achieve the 3D reconstruction of multiple simple magnetic targets with high precision.
Effects of Cr doping on the magnetic properties of one-dimensional spin chain system α–CoV2O6
Authors: Mulibana M. , Mohanty P. , Prinsloo A. R. E. , Sheppard C. J. , Jacobs B. S.
Published: February 2023

This study investigates the structural and magnetic properties of α–CoV2O6 and Cr doped α–CoV2O6 samples synthesized using a wet chemical method. X-ray diffraction (XRD) measurements and analysis indicate that α–CoV2O6 forms in a monoclinic crystal structure, with lattice parameters a = 9.26 Å, b = 3.50 Å, c = 6.62 Å, β = 111.42°, and α = γ = 90°. The magnetic properties of the compounds were probed using a vibrating sample magnetometer (VSM), by measuring the temperature, T, field, μ0H, and time, t, dependence of magnetization, M. The compounds take on an antiferromagnetic (AFM) order at 0.1 T, with an enhancement of the magnetization below 6.5 K. Cr doping resulted in an enhancement of magnetization below TN. M(μ0H) isotherms show metamagnetic transitions with a 1/3 magnetization plateau for both samples. A large hysteresis is observed for fields less than 5 T and is attributed to frozen metastable, irreversible states. M(T) data at 2.5 T and 5 T shows that the metamagnetic transitions take both compounds from an AFM to an intermediate ferrimagnetic (FI) state and ferromagnetic (FM) state at high fields. No significant changes in TN were observed with Cr doping. Zero-field-cooled (ZFC) and field-cooled (FC) bifurcation was observed for fields between 1 T and 3 T, attributed to spin-glass-like freezing of the samples at TSG. The spin-glass behaviour of the samples was confirmed using the Gabay-Toulouse (G-T) line and M(t) curves.
The magnetic and magnetocaloric properties of Al-rich Al0.85+xSi0.15Fe2B2 compounds prepared by drop-casting
Authors: Stillwell Kyra , Kramer Noah , Birch Bryan , Reese Brandon , Pathak Arjun K. , Khan Mahmud
Published: February 2023

Owing to the relative abundance of its constituent elements and large magnetocaloric properties observed near room temperature, the AlFe2B2 system has attracted much attention recently. Here, we have studied the magnetic and magnetocaloric properties of Al0.85+xSi0.15Fe2B2 (x = 0.2, 0.4) prepared by drop-casting followed by annealing and acid treatment. The second order ferromagnetic phase transitions were observed near room temperature (∼298–305 K) and peak magnetic entropy changes (−ΔSM) of more than −6 J kg−1 K−1 were observed for a field change of 5 T. The results are discussed in terms of the impurity phases formed in the compounds due to excess aluminum.
Magnetocaloric properties of Co-doped Mn0.5Fe0.5Ni1−xCoxSi0.94Al0.06 intermetallic alloys
Authors: Bhattacharjee Sharmistha , Kramer Noah , Hanley Christopher , Pathak Arjun K. , Khan Mahmud
Published: February 2023

We have synthesized a series of Co-doped Mn0.5Fe0.5Ni1−xCoxSi0.94Al0.06 (0.025 ≤ x ≤ 0.05) alloys by arc melting followed by a rapidly quenched vacuum suction casting technique and studied the magnetic and magnetocaloric properties of the system. All measurements were performed on the as-cast and annealed samples. X-ray diffraction data indicated that the samples exhibited a hexagonal phase at room temperature. Magnetization data showed that the annealed samples exhibited significantly larger transition temperatures than the as-cast samples. All samples showed the first-order phase transition with a thermomagnetic hysteresis of more than 20 K. The phase transitions were accompanied by isothermal entropy changes of as large as −16.4 J kg−1 K−1 and −42.4 J kg−1 K−1 for field changes of 20 and 50 kOe, respectively. Large refrigeration capacities and temperature averaged entropy changes of up to 201 J/kg and 34.05 J kg−1 K−1, respectively, were observed for a field change of 50 kOe.
Effects of annealing temperature on the magnetic properties of highly crystalline biphase iron oxide nanorods
Authors: Attanayake S. B. , Chanda A. , Das R. , Phan M. H. , Srikanth H.
Published: February 2023

We report on the effects of annealing temperatures ranging from 225 °C to 325 °C on the magnetic properties of high aspect ratio iron oxide nanorods consisting of a ferrimagnetic Fe3O4 phase and an antiferromagnetic α-Fe2O3 phase in an as-prepared state. Annealing at the aforementioned temperatures under a constant flow of O2 for 3 h leads to an increment of the volume fraction of the antiferromagnetic α-Fe2O3 phase and concomitant enhancement of the crystallinity of the ferrimagnetic Fe3O4 phase. These opposing effects compete with each other, resulting in a decrease in global magnetization with increasing the annealing temperature. The desirable magnetic properties are achieved for the sample annealed at 250 °C. For all samples investigated, we observed an increase in low field magnetization at low temperatures after the sample is field cooled in the presence of a 1T magnetic field, which we attribute to the ordering of macro-spins of the weakly ordered antiferromagnetic α-Fe2O3 phase in the presence of the cooling field. Our study will pave the way for determining the optimal conditions to enhance the magnetic characteristics in iron oxide nanorods, which will enable its use in spintronics and biomedical applications.
Skew angle estimation and alleviation based multi-layer perceptron in V-shaped read-head array BPMR systems
Authors: Fatika K. A. , Koonkarnkhai S. , Kovintavewat P. , Warisarn C.
Published: February 2023

The demand for a massive storage device has kept rising and it has led to the emergence of advanced technology with a vast storage capacity. Achieving this idea might bring some obstacles called two-dimensional interference as well as a skew angle (SA). Array-reader-based magnetic recording can be the potential to give a better performance in the system by reading multiple tracks simultaneously. This paper investigates a V-shaped read-head array (VRA) with three read sensors performance on five levels of skew angle consideration in three different zones of hard disk drive. VRA with three read sensors is being grouped; therefore, SA can be considered as the change in this group movement. To achieve a good system performance, we propose an SA estimation method for bit-patterned media recording systems by computing a specific target by three readback sequences before estimating the SA value and finally detecting the data. Both estimation and detection processes are carried out using a neural network method known as multilayer perceptron.
Divergent sensory and immune gene evolution in sea turtles with contrasting demographic and life histories
Authors: Bentley Blair P. , Carrasco-Valenzuela Tomás , Ramos Elisa K. S. , Pawar Harvinder , Souza Arantes Larissa , Alexander Alana , Banerjee Shreya M. , Masterson Patrick , Kuhlwilm Martin , Pippel Martin , Mountcastle Jacquelyn , Haase Bettina , Uliano-Silva Marcela , Formenti Giulio , Howe Kerstin , Chow William , Tracey Alan , Sims Ying , Pelan Sarah , Wood Jonathan , Yetsko Kelsey , Perrault Justin R. , Stewart Kelly , Benson Scott R. , Levy Yaniv , Todd Erica V. , Shaffer H. Bradley , Scott Peter , Henen Brian T. , Murphy Robert W. , Mohr David W. , Scott Alan F. , Duffy David J. , Gemmell Neil J. , Suh Alexander , Winkler Sylke , Thibaud-Nissen Françoise , Nery Mariana F. , Marques-Bonet Tomas , Antunes Agostinho , Tikochinski Yaron , Dutton Peter H. , Fedrigo Olivier , Myers Eugene W. , Jarvis Erich D. , Mazzoni Camila J. , Komoroske Lisa M.
Published: February 2023

Sea turtles represent an ancient lineage of marine vertebrates that evolved from terrestrial ancestors over 100 Mya. The genomic basis of the unique physiological and ecological traits enabling these species to thrive in diverse marine habitats remains largely unknown. Additionally, many populations have drastically declined due to anthropogenic activities over the past two centuries, and their recovery is a high global conservation priority. We generated and analyzed high-quality reference genomes for the leatherback (
Dermochelys coriacea
) and green (
Chelonia mydas
) turtles, representing the two extant sea turtle families. These genomes are highly syntenic and homologous, but localized regions of noncollinearity were associated with higher copy numbers of immune, zinc-finger, and olfactory receptor (OR) genes in green turtles, with ORs related to waterborne odorants greatly expanded in green turtles. Our findings suggest that divergent evolution of these key gene families may underlie immunological and sensory adaptations assisting navigation, occupancy of neritic versus pelagic environments, and diet specialization. Reduced collinearity was especially prevalent in microchromosomes, with greater gene content, heterozygosity, and genetic distances between species, supporting their critical role in vertebrate evolutionary adaptation. Finally, diversity and demographic histories starkly contrasted between species, indicating that leatherback turtles have had a low yet stable effective population size, exhibit extremely low diversity compared with other reptiles, and harbor a higher genetic load compared with green turtles, reinforcing concern over their persistence under future climate scenarios. These genomes provide invaluable resources for advancing our understanding of evolution and conservation best practices in an imperiled vertebrate lineage.
Resolving content moderation dilemmas between free speech and harmful misinformation
Authors: Kozyreva Anastasia , Herzog Stefan M. , Lewandowsky Stephan , Hertwig Ralph , Lorenz-Spreen Philipp , Leiser Mark , Reifler Jason
Published: February 2023

In online content moderation, two key values may come into conflict: protecting freedom of expression and preventing harm. Robust rules based in part on how citizens think about these moral dilemmas are necessary to deal with this conflict in a principled way, yet little is known about people’s judgments and preferences around content moderation. We examined such moral dilemmas in a conjoint survey experiment where US respondents (N= 2, 564) indicated whether they would remove problematic social media posts on election denial, antivaccination, Holocaust denial, and climate change denial and whether they would take punitive action against the accounts. Respondents were shown key information about the user and their post as well as the consequences of the misinformation. The majority preferred quashing harmful misinformation over protecting free speech. Respondents were more reluctant to suspend accounts than to remove posts and more likely to do either if the harmful consequences of the misinformation were severe or if sharing it was a repeated offense. Features related to the account itself (the person behind the account, their partisanship, and number of followers) had little to no effect on respondents’ decisions. Content moderation of harmful misinformation was a partisan issue: Across all four scenarios, Republicans were consistently less willing than Democrats or independents to remove posts or penalize the accounts that posted them. Our results can inform the design of transparent rules for content moderation of harmful misinformation.
ELT coursebooks for primary school learners
Authors: Peng Mei , Shi Yangyang , Zhang Ping
Published: February 2023

This article reports on the findings of a comparative study on songs in four English coursebook series for primary school learners, with two published in China and another two in the UK. Detailed analysis focuses on the number, the coverage, the teaching purposes, and the instructional arrangements of songs. The findings show that although the total number of songs in coursebooks from China outnumbers that from the UK, no correlation exists between learners’ grade levels and the number of songs in each fascicle. The study further demonstrates that the purposes of songs in all four series are mainly to arouse learners’ interest, to improve pronunciation, and to enhance vocabulary and sentence structure understanding, revealing a lack of due attention to fostering learners’ intercultural awareness. Regarding the pedagogical approach and other instructional arrangements, British coursebooks feature a more diversified approach, highlighting the integration of learners’ physical, psychological and cognitive development, whereas Chinese coursebooks concentrate on providing simplistic and unified instructions which may pose a challenge for novice teachers but an opportunity for experienced teachers. Based on the findings, recommendations are offered to future coursebook writers.
Macrophages promote anti-androgen resistance in prostate cancer bone disease
Authors: Li Xue-Feng , Selli Cigdem , Zhou Han-Lin , Cao Jian , Wu Shuiqing , Ma Ruo-Yu , Lu Ye , Zhang Cheng-Bin , Xun Bijie , Lam Alyson D. , Pang Xiao-Cong , Fernando Anu , Zhang Zeda , Unciti-Broceta Asier , Carragher Neil O. , Ramachandran Prakash , Henderson Neil C. , Sun Ling-Ling , Hu Hai-Yan , Li Gui-Bo , Sawyers Charles , Qian Bin-Zhi
Published: February 2023

Metastatic castration-resistant prostate cancer (PC) is the final stage of PC that acquires resistance to androgen deprivation therapies (ADT). Despite progresses in understanding of disease mechanisms, the specific contribution of the metastatic microenvironment to ADT resistance remains largely unknown. The current study identified that the macrophage is the major microenvironmental component of bone-metastatic PC in patients. Using a novel in vivo model, we demonstrated that macrophages were critical for enzalutamide resistance through induction of a wound-healing–like response of ECM–receptor gene expression. Mechanistically, macrophages drove resistance through cytokine activin A that induced fibronectin (FN1)-integrin alpha 5 (ITGA5)–tyrosine kinase Src (SRC) signaling cascade in PC cells. This novel mechanism was strongly supported by bioinformatics analysis of patient transcriptomics datasets. Furthermore, macrophage depletion or SRC inhibition using a novel specific inhibitor significantly inhibited resistant growth. Together, our findings elucidated a novel mechanism of macrophage-induced anti-androgen resistance of metastatic PC and a promising therapeutic approach to treat this deadly disease.