Field In Different Directions Research Articles

Exploring the influence of external electric fields on the catalytic pyrolysis of oil shale kerogen molecules

Oil shale is a widely distributed and abundant sedimentary rock that can be converted into shale oil through pyrolysis, providing a supplementary solution to the increasing scarcity of conventional fossil energy. However, the traditional pyrolysis process of oil shale faces problems such as low oil yield, high energy consumption, and poor oil quality. Recent experiments have demonstrated that using an external electric field to catalyze the pyrolysis of oil shale can address these problems. However, due to the complex physical and chemical properties of oil shale and its pyrolysis process, the catalytic mechanisms and effects have not been reasonably explained. To address these issues, this study uses density functional theory to calculate the properties of oil shale molecules under external electric fields of different directions and strengths. The results indicate that at electric field strengths far exceeding experimental conditions, the external electric field does have a certain catalytic effect on oil shale, which varies depending on the molecule. However, at electric field strengths achievable in actual laboratory conditions, the catalytic effect of the electric field on oil shale is not significant. Therefore, the mechanisms revealed by past experiments on the catalytic effects of electric fields on oil shale pyrolysis may be partially flawed. This study not only fills the gap in understanding the mechanisms of external electric field catalysis of oil shale but also provides a theoretical foundation for future applications of electric fields in catalyzing oil shale.

Direct and inverse magnetocaloric effects in magnetostrictive GdMn2Ge2 with field-induced metamagnetic transition

Heavy rare-earth-based ternary intermetallic compounds with the formula RT2X2 have drawn great interest because of their multiple magnetic transitions and various magnetic structures. Here, anisotropic magnetic behaviors, magnetocaloric effects (MCEs), and magnetostriction effects in single-crystalline GdMn2Ge2 are studied in two different directions. Experiments show a magnetic transition characterized by a sudden decrease in magnetization for μ0H//a and a sharp increase for μ0H//c at Tt. The transition is driven by lower temperatures for μ0H//a, contrasting that for μ0H//c with an increase in the magnetic field. An inverse MCE is observed for μ0H//a with a maximum magnetic entropy change (−ΔSMmax) of −7.4 J kg−1 K−1 (μ0ΔH = 6 T), while a direct MCE is obtained for μ0H//c with an −ΔSMmax of 8.0 J kg−1 K−1 under the same magnetic field change. Moreover, a remarkable field-induced metamagnetic transition and a magnetostriction effect are observed simultaneously at Tt, indicating strong magneto-lattice coupling. The T-μ0H phase diagrams are constructed based on the magnetic properties. The coexistence of direct and inverse MCEs is discussed and is due to the spin-flop of Mn and anisotropic magnetic properties under magnetic fields in different directions.

Optimal weak measurement scheme for chiral molecular detection based on photonic spin Hall effect.

In this paper, we propose a precision method to measure the chiroptical signal of Artemisinin solutions using the photonic spin Hall effect (PSHE) on the Ce:YIG-YIG-SiO2 structure as a probe. The effects of transmission distance, incident angles, applied magnetic fields of different directions, and beam waist of light on the weak measurement system are analytically investigated through simulations. It is found that decreasing the beam waist of the incident spot, increasing the incident angle, increasing the transmission distance, and adding a longitudinal magnetic field is conducive to enhancing the amplification transverse shift of PSHE, thus the measurement sensitivity is greatly improved. Based on the optimal weak measurement scheme, the detection limit for concentration measurement of artemisinin based on optical rotatory (OR) was reduced to 0.05 mg/ml. The measurement precision of the OR angle has been improved to 10-7rad.

Large anomalous Hall effect and unusual domain switching in an orthorhombic antiferromagnetic material NbMnP

Specific antiferromagnetic (AF) spin configurations generate large anomalous Hall effects (AHEs) even at zero magnetic field through nonvanishing Berry curvature in momentum space. In addition to restrictions on AF structures, suitable control of AF domains is essential to observe this effect without cancellations among its domains; therefore, compatible materials remain limited. Here we show that an orthorhombic noncollinear AF material, NbMnP, acquired AF structure-based AHE and controllability of the AF domains. Theoretical calculations indicated that a large Hall conductivity of ~230 Ω−1cm−1 originated from the AF structure of NbMnP. Symmetry considerations explained the production of a small net magnetization, whose anisotropy enabled the generation and cancellation of the Hall responses using magnetic fields in different directions. Finally, asymmetric hysteresis in NbMnP shows potential for the development of controllability of responses in AF materials.

Deformation of a magnetic fluid droplet with an immersed magnetizable body under uniform magnetic fields

The effect of a uniform applied tilted magnetic field on the deformation of a magnetic fluid droplet (resting on a horizontal plane) with an immersed magnetizable ball is investigated numerically and compared with experimental data. It is shown that the ball takes its equilibrium position in the droplet at a certain levitation height above the plane under a uniform tilted field. A 3D mathematical model is used to predict the deformation of the droplet under uniform fields of different directions and magnitudes. The calculated drop shapes are in good agreement with the experimental ones, especially for small volumes and high magnetic fields.

Analysis of Movement and Activities of Handball Players Using Deep Neural Networks

This paper focuses on image and video content analysis of handball scenes and applying deep learning methods for detecting and tracking the players and recognizing their activities. Handball is a team sport of two teams played indoors with the ball with well-defined goals and rules. The game is dynamic, with fourteen players moving quickly throughout the field in different directions, changing positions and roles from defensive to offensive, and performing different techniques and actions. Such dynamic team sports present challenging and demanding scenarios for both the object detector and the tracking algorithms and other computer vision tasks, such as action recognition and localization, with much room for improvement of existing algorithms. The aim of the paper is to explore the computer vision-based solutions for recognizing player actions that can be applied in unconstrained handball scenes with no additional sensors and with modest requirements, allowing a broader adoption of computer vision applications in both professional and amateur settings. This paper presents semi-manual creation of custom handball action dataset based on automatic player detection and tracking, and models for handball action recognition and localization using Inflated 3D Networks (I3D). For the task of player and ball detection, different configurations of You Only Look Once (YOLO) and Mask Region-Based Convolutional Neural Network (Mask R-CNN) models fine-tuned on custom handball datasets are compared to original YOLOv7 model to select the best detector that will be used for tracking-by-detection algorithms. For the player tracking, DeepSORT and Bag of tricks for SORT (BoT SORT) algorithms with Mask R-CNN and YOLO detectors were tested and compared. For the task of action recognition, I3D multi-class model and ensemble of binary I3D models are trained with different input frame lengths and frame selection strategies, and the best solution is proposed for handball action recognition. The obtained action recognition models perform well on the test set with nine handball action classes, with average F1 measures of 0.69 and 0.75 for ensemble and multi-class classifiers, respectively. They can be used to index handball videos to facilitate retrieval automatically. Finally, some open issues, challenges in applying deep learning methods in such a dynamic sports environment, and direction for future development will be discussed.

Electric Field Effects on Water and Ion Structure and Diffusion at the Orthoclase (001)–Water Interface

Understanding the electrochemical properties of mineral–water interfaces tends to rely upon electrical double layer (EDL) models, but these models are based on the assumption that electrostatic equilibrium is constantly maintained. In reality, interfacial reactions, ion diffusion, and their electrochemical signatures are based in nonequilibrium conditions of locally or globally imbalanced electrical fields where current EDL models have limited purview. Here, we performed molecular dynamics (MD) simulations of the orthoclase (001) surface in contact with a 1 M NaCl aqueous solution under various electric fields, to explore the interplay between EDL structure and dynamics when perturbed by electric fields of different directions and strengths, by confinement, and by different distributions of structural surface charge. The simulations showed that confinement between two opposing (001) surfaces led to the development of an induced field when the applied field was perpendicular to the surfaces and, as a result, to ionic diffusion coefficients that were independent of electric field strength. In contrast, when the applied field was parallel to the surfaces, confinement resulted in ionic diffusion coefficients that were more strongly dependent on the magnitude of the electric field than in bulk water. Differences in the density and distribution of aluminol groups on the two surfaces had a significant impact on how the interfacial structure and dynamics varied in the presence of an electric field. Notably, these differences resulted in an electro-osmotic flow with opposite directions at the two surfaces under parallel applied electric field. Overall, the MD simulations highlighted the importance of considering atomic-level structure and heterogeneities when developing models of the electrochemical properties of mineral–water interfaces.

Production of magnetic field due to heavy ion collisions around transition energy

Isospin quantum molecular dynamics (IQMD) model is a reliable computational tool for the study of various phenomena (multi fragmentation, anisotropic flow, nuclear stopping) from low to intermediate heavy ion collisions (HICs). Here, simulation has been carried out for the magnetic field generated during non-central HICs using the IQMD model. The effect of various parameters, such as centrality, angular momentum, rapidity and incident energy has been thoroughly investigated on the magnetic field with the evolution of time and space. It has been observed that the rapidity bin significantly impacts the magnitude of the magnetic field in different directions. Furthermore, the magnetic field produced during HIC leads to a notable impact on the in-plane momentum of the proton and neutron.

Effects of Magnetic Fields in Arc Welding, Laser Welding, and Resistance Spot Welding: A Review

The pictures show the effect of magnetic fields in different directions, including welding direction, transverse, longitudinal and cusp magnetic fields, on the shape of welding arc and molten pool. The magnetic field can significantly affect the arc morphology and droplet transfer, as well as the macro morphology and microstructure of the weld bead. Further information can be found in the article, number 2200682 by Yonghua Shi, and co-workers.

Effects of edge hydrogenation and applied electric field on the structure and electrical properties of zigzag silicene nanoribbons by SCC-DFTB calculations

The effects of edge hydrogenation and applied electric field in different directions on the geometrical structure and electrical properties of zigzag silicene nanoribbons (ZSiNRs) with different period widths (width = 2,3,4) were investigated by using a self-consistent charge density functional tight-binding (SCC-DFTB) method. The results show that the degree of warpage of the ZSiNRs is significantly changed by hydrogenation, while the bond length and bond angle are less affected. The edge hydrogenation reduces the Si-dangling bonds in the nanoribbons, which increased the binding energy of nanoribbon and enhanced system stability. In the absence of an electric field, the unhydrogenated nanoribbons with different period widths all exhibit semiconducting properties, and the hydrogenated nanoribbons exhibit metallic or semi-metallic properties. Under the vertical external electric field in the z-direction, the stability and energy gap of the unhydrogenated nanoribbons are sensitive to the change of strength, and the oscillation fluctuation is large. With the increase of strength, the atoms in the outermost four layers of the nanoribbons show obvious charge gain and loss. When the vertical electric field is applied to the hydrogenated nanoribbons, the energy gap changes are related to the period width. Their electrical properties realized the conversion between the semi-metal properties and the direct band gap semiconductor properties. Charge transfer occurs between the adjacent two layers of atoms. Under the same electric field strength, the amount of charge transfer increases from left to right along the direction of the width of the nanoribbon; at the same time, with the increase of the electric field strength, the amount of charge transfer also presents an increasing trend.

Spatial-temporal measurement of waves in laboratory based on binocular stereo vision and image processing

Acquisition of wave field data is essential for hydrodynamics studies. Current studies show deficiencies in the spatial measurement of wave fields in the laboratory, and a more efficient method is urgently needed. A stereo imaging method was proposed for the spatial-temporal measurement of waves in the laboratory based on binocular stereo vision and digital image processing. Then, a series of regular and focused waves were simulated in a wave flume to examine the feasibility and reliability of the method by comparison with the measurements by wave probes. Floating particles were evenly sprinkled on the water surface as the representation of the water-air interface, providing texture features for wave surface images and allowing the realization of dense reconstruction. Synchronized cameras provided the synchronized stereo pairs sequence for each wave, and temporal reconstruction was achieved by processing frame by frame. The 4D spatial-temporal volume for every wave could be constructed. Subsequently, spatial slices of the volume obtained the instantaneous profiles of the wave field in different directions. Temporal slices obtained the wave time series at a fixed point, which were compared with the measurements of the standard resistive probe to verify the accuracy. The results showed that the proposed method was capable of measuring the spatial-temporal field of waves efficiently and precisely and offered the potential to measure more complex wave fields in nonlinear wave-structure interactions.

Regulating structure and flow of ionic liquid confined in nanochannel using water and electric field

Developing regulation method for the structure and flow of ionic liquids (ILs) in the nanochannel is of great importance to their application in nanodevice. For this purpose, the density and charge distribution and the flow behavior of [EMIM][BF4] blended with water as diluent and imposed electric field in nanochannel are studied using molecular dynamic simulation method in this work. The results reveal that the addition of water can weaken the stratification effect of density and charge distribution while doesn’t significantly change the micro-structure of [EMIM][BF4], while the electric field in different directions results different influence on the stratification effect. Addition of water can make a significant improvement in the flow velocity of [EMIM][BF4] and change its flow state. Imposing electric field in flow direction can accelerate the flow, but imposing electric field perpendicular to nanochannel handles the flow.

Effects of local exchange field in different directions on spin transport of stanene

Topological insulator is a new quantum state of matter in which spin-orbit coupling gives rise to topologically protected gapless edge or surface states. The nondissipation transport properties of the edge or surface state make the topological device a promising candidate for ultra-low-power consumption electronics. Stanene is a type of two-dimensional topological insulator consisting of Sn atoms arranged similarly to graphene and silicene in a hexagonal structure. In this paper, the effects of various combinations of local exchange fields on the spin transport of stanene nanoribbons are studied theoretically by using the non-equilibrium Green's function method. The results show that the spin-dependent conductance, edge states, and bulk bands of stanene are significantly dependent on the direction and strength of the exchange field in different regions. Under the joint action of the exchange fields in [I: <inline-formula><tex-math id="M12">\begin{document}$ \pm Y $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M12.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M12.png"/></alternatives></inline-formula>, II: <inline-formula><tex-math id="M13">\begin{document}$ +Z $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M13.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M13.png"/></alternatives></inline-formula>, III: <inline-formula><tex-math id="M14">\begin{document}$ \pm Y $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M14.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M14.png"/></alternatives></inline-formula>] direction, the edge states form a band-gap under the influence of the <i>Y</i>-direction exchange field. The band-gap width is directly proportional to the exchange field strength <i>M</i>, and the conductance is zero in an energy range of <inline-formula><tex-math id="M15">\begin{document}$ -M<E<M $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M15.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M15.png"/></alternatives></inline-formula>. When the exchange fields in the direction of <inline-formula><tex-math id="M16">\begin{document}$ +Z $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M16.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M16.png"/></alternatives></inline-formula> or <inline-formula><tex-math id="M17">\begin{document}$ -Z $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M17.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M17.png"/></alternatives></inline-formula> are applied, respectively, to the upper edge region and the lower edge region at the same time, the spin-up energy band and the spin-down energy band move to a high energy region in opposite directions, and strong spin splitting occurs in the edge state and bulk bands. Increasing the strength of the exchange field, the range of spin polarization of conductance spreads from the high energy region to the low energy region. When the directions of the exchange field are [I: <inline-formula><tex-math id="M18">\begin{document}$ \mp Z $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M18.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M18.png"/></alternatives></inline-formula>, II: <inline-formula><tex-math id="M19">\begin{document}$ \pm Y $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M19.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M19.png"/></alternatives></inline-formula>, III: <inline-formula><tex-math id="M20">\begin{document}$ \pm Z $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M20.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M20.png"/></alternatives></inline-formula>], the edge states are spin degenerate, but the weak spin splitting occurs in the bulk bands. Under the condition of different exchange field strengths, the spin-dependent conductance maintains a conductance platform of <inline-formula><tex-math id="M21">\begin{document}$ G_\sigma=e^2/h $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M21.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M21.png"/></alternatives></inline-formula> in the same energy range of <inline-formula><tex-math id="M22">\begin{document}$ -\lambda_{\rm so} <E<\lambda_{\rm so} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M22.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20220277_M22.png"/></alternatives></inline-formula>.

The influence of magnetic field on the beam quality of relativistic electron beam long-range propagation in near-Earth environment

In recent years, it has been proposed to use satellite-mounted radio-frequency (RF) accelerators to produce high-current relativistic electron beams to complete debris removal tasks. However, when simulating the long-range propagation (km-range) process of the electron beam, it is difficult to directly use the particle-in-cell method to simultaneously consider the space charge effect of beam and the influence of the geomagnetic field. Owing to these limitations, in this paper, we proposed a simplified method. The ps-range electronic micropulses emitted by the RF accelerator were transmitted and fused to form a ns-range electron beam; then, combined with the improved moving window technology, the model was constructed to simulate the long-range propagation process of the relativistic electron beam in near-Earth environment. Finally, by setting the direction of movement of the beam to be parallel, perpendicular and at an inclination of 3° to the magnetic field, we analyzed and compared the effects of the applied magnetic fields in different directions on the quality of the beam during long-range propagation. The simulation results showed that the parallel state of the beam motion and magnetic fields should be achieved as much as possible to ensure the feasibility of the space debris removal.

Dynamic analysis and active control of hard-magnetic soft materials

ABSTRACT The hard-magnetic soft materials which can sustain high residual magnetic flux density gradually attract the attention of researchers because of potential applications in soft robotics and biomedical fields. In this work, we focus on the dynamic response of hard-magnetic soft materials. The dynamic motion equations are derived by the Euler-Lagrange equation. The effects of the aspect radio on the nonlinear vibration of the hard-magnetic soft cuboid under the force and applied magnetic fields in different directions are investigated. The amplitude-frequency curves demonstrate that the aspect ratio also has an influence on the frequency and amplitude of the primary resonance. Moreover, to eliminate undesired vibration responses, the PID controller is applied to the vibration of the hard-magnetic soft materials, and the desired results can be obtained.

A novel electro-mechanical technique for efficient dispersion of carbon nanotubes in liquid media

In this paper, we introduce a method to disperse carbon nanotubes (CNTs) within liquid media, established based on the applied hydrodynamic stress in the alignment process of the CNTs using an electric field. The main novelty of this technique is the capability of CNTs length protection and real-time control of the dispersion degree. Herein, the agglomerates and bundles are frequently induced by switching the field in different directions, and subsequently, the CNTs are separated from the main agglomerates. UV-Vis and dynamic light scattering spectroscopies and optical microscope analysis determined the dispersibility of the presented technique is very satisfying. The CNT's length distribution was assessed by the field emission scanning electron microscope. The results revealed that the shortening of CNTs is approximately 230% less than the well-known ultrasonic and melt mixing process. This is due to the unknown fatigue mechanism in which the required energy for dispersing CNTs is much less than CNT-CNT interaction energy. In addition to the capability of CNTs length protection, this method reduces the post-dispersed CNTs’ structural defects strikingly, certified by Raman spectroscopy. For real-time monitoring of the dispersion, the time-dependent voltage is measured. It was found that more reduction in the voltage corresponds to more dispersion.

Terahertz Characteristics of Magnetic Fluid Based on Microfluidic Technology

Magnetic fluid is a new functional material with both liquid fluidity and solid magnetism, which has important application value in medicine, biology, and so on. In this study, terahertz technology and microfluidic technology were combined to investigate the terahertz transmission characteristics of a magnetic fluid in different magnetic fields and different electric fields. In the external magnetic field, the intensity of the terahertz spectrum increased with an increase in the magnetic field intensity, and the response to the magnetic field in different directions was different. Under the applied electric field, the intensity of the terahertz spectrum decreased with an increase in the electric field intensity. This method is convenient for studying the terahertz characteristics of magnetic fluid and provides technical support for in-depth studies of magnetic fluid.

Nonreciprocal optical solitons in a spinning Kerr resonator

We propose a spinning nonlinear resonator as an experimentally accessible platform to achieve nonreciprocal control of optical solitons. Nonreciprocity here results from the relativistic Sagnac-Fizeau optical drag effect, which is different for pump fields propagating in the spinning direction or in the direction opposite to it. We show that in a spinning Kerr resonator, different soliton states appear for the input fields in different directions. These nonreciprocal solitons are more stable against losses induced by inter-modal coupling between clockwise and counterclockwise modes of the resonator. Our work builds a bridge between nonreciprocal physics and soliton science, providing a promising route towards achieving soliton-wave optical isolators and one-way soliton communications.

Self-Assembly Magnetic Micro- and Nanospheres and the Effect of Applied Magnetic Fields.

The impact of in-plane and perpendicular magnetic fields on the spatial arrangement of superparamagnetic nanospheres is explored. We utilize nanosphere self-organization methods like Spin Coating and Drop-Casting in the presence of magnetic fields. In this way, the additional parameter of the long range magnetic dipolar interactions is introduced to the competing nanosphere–surface and nanosphere–nanosphere interactions, which control order and agglomeration. We present a comparative analysis of the self-assembly characteristics with respect to the different methods and the effect of the applied field in different directions. Under zero field perfect hexagonal arrays can be obtained by spin coating. Parallel applied fields tend to create directional patterns, while perpendicular favor 3D-accumulation.

A multi-directional magnetic field sensor based on tapered few mode fiber and magnetic fluid

A multi-directional magnetic field sensor based on tapered few mode fiber and magnetic fluid is proposed via a single mode fiber (SMF)-tapered few mode fiber (TFMF)-SMF structure. Magnetic fluid (MF) is encapsulated outside the TFMF to detect magnetic fields in different directions. The experimental results show that the change trend of the transmission spectrum is related to the direction of the magnetic field, independent of the length of the taper. When a vertical magnetic field is applied to the sensor, the transmission spectrum is red-shifted with the decrease of the magnetic field intensity. When a parallel magnetic field is applied to the sensor, the transmission spectrum is blue-shifted with the decrease of the magnetic field intensity. For the same sensor, the magnetic field sensitivity in vertical direction is significantly higher than that in parallel direction, and can be up to 70,792.85 pm/Oe by applying a magnetic field direction of 180°. The sensor has the advantages of simple fabrication and high sensitivity, and has a good application prospect in scientific research and other magnetic field measurement.