bluuebunny/crossref_metadata_2025 huggingface dataset:
A second-order phase field-lattice Boltzmann model with equation of state inputting for two-phase flow containing soluble surfactants
Authors: Zhang Shi-Ting , Hu Yang , Li Qianping , Li De-Cai , He Qiang , Niu Xiao-Dong
Published: February 2024

In this paper, we propose a phase field-lattice Boltzmann (LB) model with an equation of state (EOS) inputting for two-phase flow containing soluble surfactants. In this model, both the order parameter for the phase field and the surfactant concentration are described by second-order partial differential equations, along with Navier–Stokes equations for the flow field. Changes in surfactant concentration do not affect the order parameter distribution; hence, an unwanted sharpening effect cannot arise. Most importantly, in the existing models, the EOS of surface tension is determined by posterior simulation tests instead of being directly set as an input parameter before the simulations. Hence, it is difficult to determine the model parameters in practical applications. To address this issue, we systematically develop a fully analytical EOS for surface tension based on the Gibbs–Duhem equation. Subsequently, an approximate explicit form for EOS is provided by utilizing the Jacobi–Gauss quadrature rule. Furthermore, a multiple-relaxation-time LB scheme is utilized to numerically solve the governing equations of three physical fields. Two benchmark examples are simulated to validate the accuracy of the present model. The consistency between the numerical results and the analytical EOS is verified. Moreover, the dynamics of droplets with surfactant in simple shear flow is investigated, unveiling the profound impact of various factors, such as surfactant bulk concentration, capillary number, and viscosity ratio, on single droplet deformation and two equal-sized droplets interaction. A detailed exploration of the fluid mechanism involved in two-phase flow with soluble surfactants is presented.
Weak second-order quantum state diffusion unraveling of the Lindblad master equation
Authors: Adhikari Sayak , Baer Roi
Published: February 2024

Simulating mixed-state evolution in open quantum systems is crucial for various chemical physics, quantum optics, and computer science applications. These simulations typically follow the Lindblad master equation dynamics. An alternative approach known as quantum state diffusion unraveling is based on the trajectories of pure states generated by random wave functions, which evolve according to a nonlinear Itô–Schrödinger equation (ISE). This study introduces weak first-order and second-order solvers for the ISE based on directly applying the Itô–Taylor expansion with exact derivatives in the interaction picture. We tested the method on free and driven Morse oscillators coupled to a thermal environment and found that both orders allowed practical estimation with a few dozen iterations. The variance was relatively small compared to the linear unraveling and did not grow with time. The second-order solver delivers a much higher accuracy and stability with bigger time steps than the first-order scheme, with a small additional workload. However, the second-order algorithm has quadratic complexity with the number of Lindblad operators as opposed to the linear complexity of the first-order algorithm.
Effect of loading rate on the mechanical and seepage characteristics of gas-bearing coal–rock and its mechanical constitutive model
Authors: Wang Kai , Zhao Enbiao , Guo Yangyang , Du Feng , Ding Kai
Published: February 2024

The overall failure of gas-bearing coal–rock composite is the main cause of composite dynamic disasters. Investigating the mechanical-seepage characteristics of coal–rock specimens is the key to understanding the mechanism and minimizing composite dynamic disasters. In this paper, true triaxial mechanical experiments are designed and conducted under different maximum principal stress-loading rates. The mechanical properties, strength characteristics, and energy responses of samples under different loading rates are studied. A damage constitutive model of coal–rock specimens under different true triaxial loading rates is established; the solving methods for micro strength parameters m and F0 are described. The results show that as maximum principal stress-loading rate increases, the bearing capacity of the sample increases, the deformation parameters gradually increase, the degree of energy change increases, and the deformation failure becomes more severe. The model of gas-bearing coal–rock specimens under different true triaxial loading rates is in agreement with the test curves. Our model can provide useful references for predicting the stability of underground gas-bearing coal–rock.
An accelerated lattice Boltzmann method for natural convection coupled with convolutional neural network
Authors: Wang Zhiqiang , Xu Ying , Zhang Ying , Ke Zhaoqing , Tian Yuan , Zhao Shuting
Published: February 2024

A novel approach is proposed in the present study, which combines the lattice Boltzmann method (LBM) with convolutional neural networks and is suitable for square cavity natural convection and conjugate natural convection problems, exhibiting remarkable acceleration capabilities and potentials. The density distribution function obtained from LBM at time t and the temperature distribution function at time t+Δt under different Rayleigh numbers (Ra) are, respectively, utilized as input and output datasets for training and comparison in three convolutional neural networks, aiming to select the optimal coupling model, namely, half-Res-Unet. The coupling model can accurately simulate the natural convection in a square cavity within six times the upper limit of the Ra under the training condition, which can save the central processing unit (CPU) calculation time and the iteration steps by up to 29.2% and 30.3%, respectively. The coupling model is further extended in the current study to incorporate conjugate natural convection, enabling the accurate simulation of temperature distribution under training conditions with a thermal conductivity ratio (Ka) of 25 and an upper limit of Ra increased by 20 times. The corresponding maximum relative errors for the average Nusselt numbers (Nu) are found to be 1.8% and 0.7%, respectively, providing strong evidence for the generalization capability of the coupling model. Furthermore, the coupling model demonstrates a remarkable acceleration performance, as evidenced by its ability to reduce the CPU calculation time by up to 39.6% and iteration steps in the simulation process by 36.5%. It offers valuable insights into the integration of LBM with machine learning techniques, thereby enhancing the computational efficiency of LBM.
Co-evolution of heterogeneous cognition in spatial snowdrift game with asymmetric cost
Authors: Jing Yuxuan , Han Songlin , Feng Minyu , Kurths Jürgen
Published: February 2024

The emergence of the evolutionary game on complex networks provides a fresh framework for studying cooperation behavior between complex populations. Numerous recent progress has been achieved in studying asymmetric games. However, there is still a substantial need to address how to flexibly express the individual asymmetric nature. In this paper, we employ mutual cognition among individuals to elucidate the asymmetry inherent in their interactions. Cognition arises from individuals’ subjective assessments and significantly influences their decision-making processes. In social networks, mutual cognition among individuals is a persistent phenomenon and frequently displays heterogeneity as the influence of their interactions. This unequal cognitive dynamic will, in turn, influence the interactions, culminating in asymmetric outcomes. To better illustrate the inter-individual cognition in asymmetric snowdrift games, the concept of favor value is introduced here. On this basis, the evolution of cognition and its relationship with asymmetry degree are defined. In our simulation, we investigate how game cost and the intensity of individual cognitive changes impact the cooperation frequency. Furthermore, the temporal evolution of individual cognition and its variation under different parameters was also examined. The simulation results reveal that the emergence of heterogeneous cognition effectively addresses social dilemmas, with asymmetric interactions among individuals enhancing the propensity for cooperative choices. It is noteworthy that distinctions exist in the rules governing cooperation and cognitive evolution between regular networks and Watts–Strogatz small-world networks. In light of this, we deduce the relationship between cognition evolution and cooperative behavior in co-evolution and explore potential factors influencing cooperation within the system.
How fork-length asymmetry affects solvent connectivity and diffusion in grafted polymeric model membranes
Authors: Dorenbos G.
Published: February 2024

The hydrophilic pore morphology and solvent diffusion within model (amphiphilic) polymer membranes are simulated by dissipative particle dynamics (DPD). The polymers are composed of a backbone of 18 covalently bonded A beads to which at regular intervals side chains are attached. The side chains are composed of linear Ap chains (i.e., –A1–A2…Ap) from which two branches, [AsC] and [ArC], split off (s ≤ r). C beads serve as functionalized hydrophilic pendent sites. The branch lengths (s + 1 and r + 1) are varied. Five repeat unit designs (with general formula A3[Ap[AsC][ArC]]) are considered: A2[A3C][A3C] (symmetric branching), A2[A2C][A4C], A2[AC][A5C], A2[C][A6C] (highly asymmetric branching), and A4[AC][A3C]. The distribution of water (W) and W diffusion through nanophase segregated hydrophilic pores is studied. For similar primary length p, an increase in side chain symmetry favors hydrophilic pore connectivity and long-range water transport. C beads located on the longer [ArC] branches reveal the highest C bead mobility and are more strongly associated with water than the C beads on the shorter [AsC] branches. The connectivity of hydrophilic (W and W + C) phases through mapped replica of selected snapshots obtained from Monte Carlo tracer diffusion simulations is in line with trends found from the W bead diffusivities during DPD simulations. The diffusive pathways for protons (H+) in proton exchange membranes and for hydronium (OH−) in anion exchange membranes are the same as for solvents. Therefore, control of the side chain architecture is an interesting design parameter for optimizing membrane conductivities.
Phonon transport across rough AlGaN/GaN interfaces with varying Al–Ga atomic ratios
Authors: Yang Chao , Wang Jian , Li Zhiqiang , Liu Linhua , Fu Zhiwei , Yang Jia-Yue
Published: February 2024

Exploring interfacial thermal transport of a heterojunction interface is crucial to achieving advanced thermal management for gallium nitride-based high electron mobility transistor devices. The current research primarily focuses on material enhancements and microstructure design at the interfaces of epitaxial layers, buffer layers, and substrates, such as the GaN/SiC interface and GaN/AlN interface. Yet, the influence of different concentrations of Al/Ga atoms and interface roughness on the interfacial thermal conductance (ITC) of AlGaN/GaN interface, the closest interface to the hot spot, is still poorly understood. Herein, we focus on the rough AlGaN/GaN interface and evaluate the changes in ITC under different Al–Ga atomic concentrations and interface roughness using atomistic simulations. When the interface is completely smooth and AlGaN and GaN are arranged according to common polarization characteristic structures, the ITC gradually increases as the proportion of Al atoms decreases. When the proportion of Al atoms is reduced to 20%–30%, the impact of the interface structure on heat transfer is almost negligible. For interface models with different roughness levels, as the interface roughness increases, the ITC drops from 735.09 MW m−2 K−1 (smooth interface) to 469.47 MW m−2 K−1 by 36.13%. The decrease in ITC is attributed to phonon localization induced by rough interfaces. The phonon modes at the interface are significantly different from those in bulk materials. The degree of phonon localization is most pronounced in the frequency range that contributes significantly to heat flux. This work provides valuable physical insights into understanding the thermal transfer behaviors across the rough AlGaN/GaN interfaces.
Limiting role of dislocations in high-current AlGaN/GaN hot electron transistors
Authors: Daulton J. W. , Molnar R. J. , Brinkerhoff J. A. , Weir T. J. , Hollis M. A. , Zaslavsky A.
Published: February 2024

III-nitride-based hot electron transistors (HETs) hold significant promise as high-speed, high-power devices. In our previous work, we demonstrated high current density and common-emitter gain at room temperature. Here, we measure multiple devices at cryogenic temperatures, extending the Gummel characteristics past the onset of intervalley scattering at 77 K. We demonstrate a Gummel current gain of 4.7 at a collector current density of 2.6 MA/cm2 at 77 K as well as a peak current density exceeding 3 MA/cm2. From these data, we determine that dislocation-associated inhomogeneities play a limiting role in AlGaN/GaN HETs, controlling the current gain, density, knee voltage, and base-collector leakage. A comparison of two nominally identical devices suggests that even a modest reduction in dislocation density would result in a substantial improvement in HET performance.
Early mechanical properties and strength calculation method of slag-based alkali activated concrete
Authors: Wang Yuhua , Tang Congrong , Wang Mengjun , Yu Yong , Chen Shuai
Published: February 2024

The use of slag-based alkali-activated concrete (AAC) could effectively address the issues of resource extraction and carbon emissions caused by traditional Portland cement. In this study, the effects of the fly ash content, water–binder ratio, and alkali activation modulus on the early mechanical properties of AAC were investigated. A total of 105 cube specimens (35 sets) were designed and subjected to compressive strength tests, scanning electron microscope tests, and x-ray diffraction composition analysis. The results indicated that excellent early strength was observed in AAC, with a compressive strength reaching ∼90% of the 28th day strength before 14 days. An increase in the fly ash content and a decrease in the water–binder ratio significantly improved the compressive strength within the same age period. The impact of a lower alkaline activation modulus on strength was found to be insignificant. Based on the experimental results, a calculation method and a constitutive model for early strength were proposed, and the theoretical values exhibited a high level of agreement with the measured values.
Vortex motion in vaneless space and runner passage of pump-turbine in S-shaped region
Authors: Liu Demin , Li Zhen , Xu Lianchen , Li Jialing , Yang Yuxuan , Wang Xiaolong , Pang Jiayang , Liu Xiaobing
Published: February 2024

This study examines the S-characteristic, a key factor affecting the safe grid connection and operation of pumped-storage units, and its significant impact on the safety of pumped-storage power stations. We conducted numerical simulations and model experiments to investigate vortex motion characteristics in the vaneless space and runner passage of pump-turbines operating within the S-shaped region, along with an analysis of pressure pulsation characteristics. The accuracy of these simulations was validated through laser Doppler velocimetry experiments, and particle image velocimetry experiments were used to capture vortex motion in the vaneless space. We observed that vortices generated on the guide vane side follow the flow direction, blocking the guide vane passage, while those generated by runner blades move in the opposite direction. Employing an entropy production theory and the Liutex method, we investigated vortex distribution and hydraulic loss in the S-shaped region. The results show that reduced flow rates lead to significant vortices in the vaneless space and guide vane area, which become main contributors to energy loss in this region. These vortices, along with those in the runner passage, mainly arise from flow separation on blade and guide vane surfaces due to suboptimal inflow conditions. The study also identifies pressure fluctuations in the vaneless space, induced by a rotating stall, as the most significant pressure pulsation phenomenon, which significantly impacts the performance of the unit in both upstream and downstream directions.
Quantum mechanical model of crossing and anti-crossing points in 3D full-band Monte Carlo simulations
Authors: Zhu Mike , Bertazzi Francesco , Matsubara Masahiko , Bellotti Enrico
Published: February 2024

This work presents a 3D quantum mechanics based model to address the physics at band structure crossing/anti-crossing points in full band Monte Carlo (FBMC) simulations. The model solves the Krieger and Iafrate (KI) equations in real time using pre-computed coefficients at k-points spatially sampled within the first Brillouin zone. Solving the KI equations in real time makes this model applicable for all electric fields, which enables its use in FBMC device simulations. In this work, a two-level refinement scheme is used to aggressively sample regions in proximity to band crossings for accurate solutions to the KI equations and coarsely sample everywhere else to limit the number of k-points used. The presented sampling method is demonstrated on the band structure of silicon but is effective for the band structure of any semiconductor material. Next, the adaptation of the fully quantum KI model into the semi-classical FBMC method is discussed. Finally, FBMC simulations of hole transport in 4H silicon carbide with and without the KI model are performed. Results along different crystallographic directions for a wide range of electric fields are compared to previously published simulation and experimental values.
Design of CrxFe1−xMnCoNiGeSi high-entropy alloy with large barocaloric effect
Authors: Guo Yong , Gong Yuanyuan , Zhang Tingting , Zhang Zhishuo , Chen Bin , Chen Fenghua , Jiang Zhengyi , Xu Feng
Published: February 2024

Being a crucial research frontier, high-entropy alloys advance traditional materials in mechanical properties under various conditions. Nonetheless, other functions, like magnetic, electrical, and optical properties, of high-entropy alloys are still deficient. This paper presents a high-entropy system exhibiting a large barocaloric effect. Experimental results confirm that equiatomic FeMnCoNiGeSi and CrMnCoNiGeSi are high-entropy solid-solutions with hexagonal and orthorhombic structures at room temperature, respectively. Further tuning Fe/Cr ratio in a CrxFe1−xMnCoNiGeSi high-entropy system establishes a thermal-induced hexagonal–orthorhombic structural transformation. For the alloy with x = 0.44–0.50, the structural transformation occurs at room temperature and can be induced by applying or withdrawing hydrostatic pressure. The barocaloric effect reaches −30.6 J kg−1·K−1 when withdrawing hydrostatic pressure from 5 to 0 kbar, and the entropy change per 1 kbar is comparable to widely studied intermetallic compounds.
The influence of magnetic dipolar interaction on giant magnetoimpedance effect
Authors: Sun Xutao , Liu Jiang , Li Meiqin , Li Xin , Zhao Zhenjie
Published: February 2024

The giant magnetoimpedance (GMI) effect can be used to precisely investigate the magnetization process of samples. However, it is influenced by the magnetic interactions between the samples, among which dipolar interaction is a crucial factor to tune the GMI response and further design in magnetic device. Therefore, it is essential to study the impact of dipolar interaction on the GMI effect. Previous research was limited at the qualitative analysis. The introduction of the geometric factor between the strips and the application of the minimization of the free energy allowed for a quantitative analysis of their influence. Theoretical predictions and experimental results indicated that dipolar interaction led to an inward shift of the double peaks in the impedance curve and an increase in the maximum GMI ratio. This study enabled more accurate and precise analysis of the influence of dipolar interaction in both strip-shaped and filamentous-shaped magnetic samples on magnetic characterization. Thus, the GMI curve could expand our understanding of the internal interactions within magnetic materials and offer perspectives for the design and optimization of magnetic materials in practical applications.
Device simulations of perovskite transistors containing mobile ions and their relevance to experimental data
Authors: Shamalia Doaa , Tessler Nir
Published: February 2024

We present a device simulation of lead-halide perovskite-based thin film transistors (TFTs) containing mobile charged species to provide physical reasoning for the various experimental reports. We study the output characteristics for a range of scan duration (1/speed), average mobile ion densities, and N- and P-channel TFTs. We then directly compare our results to published data by Zeidell et al. [Adv. Electron. Mater. 4(12), 1800316 (2018)] and show that if the transistor’s measurement procedure is such that the ions’ effects are apparent, and then, our model can resolve the sign of the mobile ions in their MAPbI3−xClx TFTs (cations) and provide a good estimate of their density (∼1017 cm−3 at 200 k). Interestingly, we find that effects previously associated with channel screening are due to the ion-blocking of the charge extraction and that the incomplete saturation often reported is due to ion-induced channel shortening. Utilizing the same perovskite materials as in solar cells would allow researchers to improve their understanding of the mechanisms governing solar photovoltaics and improve their performance.
High-frequency loss modeling of nanocrystalline core considering nonuniform distribution of flux density
Authors: Meng Wenbin , Zhang Changgeng , Li Yongjian , Sun He , Wan Zhenyu
Published: February 2024

Nanocrystalline core is widely used in the design process of high-frequency transformers and inductors due to the attractive magnetic properties of nanocrystalline material. However, the flux density distribution is nonuniform in the core because the reluctance is closely related to its geometric shape. The nonuniformity of flux density distribution may cause huge calculation errors of core losses. In this paper, Finite Element Method (FEM) is used to justify taking into account nonuniform distribution of flux density during the process of core loss calculation. An improved loss separation equation considering nonuniform distribution of flux density is proposed, and the improved equation is verified through calculating and analyzing the losses of nanocrystalline cores with different wound thicknesses. Compared with the traditional loss separation equation, the accuracy is improved, and the average error of improved equation is confined in 10%.
Impurity effect on magnetic and thermal properties of S = 3/2 spin gap system Ba3Ca(Ru1−xNbx)2O9
Authors: Ochiai Yuta , Terasaki Ichiro , Yasui Yukio
Published: February 2024

We have investigated the nonmagnetic impurity effects on magnetic and thermal properties for the spin gap system Ba3CaRu2O9, which has the Ru2O9 dimers composed of two Ru5+ spins (S = 3/2). The measurements of the magnetic susceptibility and specific heat have been carried out for the polycrystalline samples of Ba3Ca(Ru1−xNbx)2O9, where the Ru5+ spins are partially substituted by the non-magnetic Nb5+ ions. We have observed the magnetic behavior of the remained Ru5+ spins derived from breaking the singlet formation by the Nb-doping. These magnetic behaviors can be understood by the S = 3/2 free spin model under an internal magnetic field. Based on the obtained results, the mechanism of the singlet formation of Ba3CaRu2O9 is discussed.
A reconfigurable bipolar coil for wireless charging systems with interoperability and misalignment tolerance characteristics
Authors: Liu Chao , Zhou Mingzhu , Zhuang Yizhan , Zhang Yiming
Published: February 2024

Wireless Power Transfer (WPT) technology has been developing rapidly in recent years. Electric Vehicles (EVs), as an emerging mode of transport, also benefit from the WPT technology. Various EV manufacturers have different coupling structures, which can lead to incompatibility problems between the coils. Meanwhile, due to the human parking, misalignment between the transmitting and receiving coils may occur. To solve these problems, this paper proposes a reconfigurable bipolar coil structure with both interoperability and misalignment tolerance. A 200-W experimental prototype is built, which can achieve 84.33% and 84.76% system transmission efficiency with vertical and horizontal bipolar coils. The effectiveness of the proposed reconfigurable bipolar coil is finally verified by comparing the computational and experimental results.
Volume optimization of high-speed surface-mounted permanent magnet synchronous motor based on sequential quadratic programming technique and analytical solution
Authors: Hoang Duy-Tinh , Nguyen Manh-Dung , Woo Jong-Hyeon , Shin Hyo-Seob , Shin Kyung-Hun , Phung Anh-Tuan , Choi Jang-Young
Published: February 2024

This study proposes an innovative approach that integrates the subdomain method with sequential quadratic programming (SQP) to optimize the volume of a high-speed surface-mounted permanent magnet synchronous motor in an air compressor operating at 110 000 rpm. Unlike conventional optimization tools that often rely on finite element analysis (FEA) software, by leveraging the subdomain method for electromagnetic modeling, we obtain an analytical solution that rapidly represents the behaviors of the motor. Subsequently, the SQP technique is applied to optimize the volume of the model while satisfying design constraints. The proposed model is verified by FEA simulation.
Measurement of magnetic properties of grain-oriented electrical steel considering multi-physics factors influence
Authors: Chen Long , Liu XianZhi , Ben Tong , Yan Dongyang , Zhang Xian
Published: February 2024

The magnetic properties of electrical steel sheets are strongly affected by the Multi-Physics Factors (MPF), such as bending stress, working temperature, and magnetization patterns. To investigate the complex magnetic properties of the material under MPF magnetizing conditions, a magnetic property measurement system is first developed, considering the effect of bending stress, temperature loading, and non-sinusoidal magnetization waveforms. Then, the magnetic and the loss properties of Grain-Oriented (GO) electrical steels under MPF magnetizing conditions are measured and discussed. Obtained results showed that bending stress and non-sinusoidal magnetization waveforms are positively correlated with the loss properties of electrical steel sheets, and elevated temperatures can mitigate the effects of bending stress and harmonics on magnetic properties and losses.
Magneto-optical characterization of TCO films using standard and enhanced configurations
Authors: Syed M. , Reza S. A. , Miller P. D. , Roop B.
Published: February 2024

Thin film samples like transparent conducting oxides (TCO) are typically investigated using measurements like Hall Effect and 4-point probe measurements. We use a sensitive AC Faraday rotation (FR) setup to study thin film samples for which a magneto-optic response is challenging to characterize. The experimental setup employs a stabilized He-Ne laser (633 nm) along with an AC magnetic field that enables lock-in detection. We investigate a series of TCO samples that are deposited on a glass substrate. The TCO samples include the more widely used Indium Tin Oxide (ITO) and the relatively newer Fluorine doped Tin Oxide films, usually referred to as FTO. These films have a magneto-optic response due to the presence of free carrier concentration and therefore measurement of this response (Verdet constant) could allow one to determine the carrier concentration of these films. Given that magneto optic responses like FR depend on the length of the sample length traveled by light, these sub-micron films pose considerable challenges in trying to extract the FR response of the film from that of the much thicker glass substrate. Furthermore, we present details of the design and FR characterization of samples using a Michelson interferometer-based measurement setup which enhances the Faraday rotation and affords a new means of studying harmonic peaks of the recorded optical signal in response to a sinusoidally-varying applied magnetic field. We compare some early results from this setup to the typical “single-pass” setup to highlight the difference in the recorded signals from the two setups. To showcase the advantages of the proposed measurements, we also include some early results from a very different type of sample, namely superparamagnetic nanoparticles (SNPs).
Bit-island arrangement and signal processing in double-layer magnetic recording technology
Authors: Sawangarom V. , Buajong C. , Kankhunthod K. , Warisarn C.
Published: February 2024

The escalating demand for high-density storage of hard disk drives has prompted the innovation of advanced technologies to significantly boost an areal density (AD). Among these, three-dimensional magnetic recording systems incorporating double recording layers and bit-patterned magnetic recording (BPMR) have currently emerged as one promising solution. Therefore, this article investigates the integration of double-layer magnetic recording and BPMR technologies which is called double-layer BPMR, aiming for a substantial increase in AD. The primary focus lies on minimizing inter-layer interference and mitigating two-dimensional interferences by optimizing bit-island sizes for both upper and lower layers under the incorporation of staggered-like recording media arrangement and an array of magneto-resistive readers. Moreover, we also employ a rate-5/6 modulation code for compensating these effects. Detailed examinations reveal that our proposed system has a superior bit-error rate performance compared with conventional single-layer BPMR system.
Reduction effect of coercivity of electroplated Fe-Pt film magnets by chloride ion in plating baths
Authors: Yanai Takeshi , Fukushima Daiki , Narabayashi Ryuta , Ogushi Naoki , Yamaguchi Yuito , Yamashita Akihiro , Nakano Masaki , Fukunaga Hirotoshi
Published: February 2024

We recently reported the electroplating of Fe-Pt thick films using plating baths with varying concentrations of NaCl, suggesting the potential for coercivity enhancement by Na ions. In the present study, our focus shifted to not Na ions but Cl ones, and we investigated the effect of the Cl ions on the crystal structures and magnetic properties of electroplated Fe-Pt films. With the increasing concentration of Cl ions, the coercivity of the films decreased. Furthermore, XRD analysis suggested that the Cl ions in the plating baths prevent the L10 ordering of the Fe-Pt crystalline phase, leading us to conclude that a Cl-free bath is favorable for preparing Fe-Pt thick-film magnets with high coercivity.
Magnetocaloric effect in aluminum doped ErCr1−xAlxO3 orthochromites
Authors: Sultana Jolaikha , Sawon Asraf , Brzykcy Grace , Pathak Arjun K. , Mishra Sanjay R.
Published: February 2024

Aluminum-doped ErCr1-xAlxO3 orthochromites prepared via autocombustion technique were investigated for their magnetic and magnetocaloric properties. X-ray diffraction confirmed that samples were orthorhombic phases with the Pbnm space group without a trace of any impurity. As analyzed via Rietveld refinement of XRD data, structural parameters such as lattice parameters, volume, bond angle, and bond lengths were affected by doping nonmagnetic Al3+ in the compound. ErCrO3 possesses the long-range antiferromagnetic ordering with a weak display ferromagnetism at TN =133 K. Low-temperature high-field magnetic study shows a decrease in Neel temperature (TN ∼ 114 K for x = 0.5), suggesting magnetic ordering suppression due to Al3+ doping. The asymptotic paramagnetic Curie temperature Tcw = −25 K suggests the predominance of antiferromagnetic interactions in ErCrO3 orthochromites, which was observed to increase with Al3+ doping. Isothermal magnetization data show changes in magnetic entropy (−ΔSMmax) and relative cooling power (RCP). The magnetic entropy change, −ΔSMmax, for ErCrO3 estimated from magnetization measurements show 11.60 J kg−1 K−1 at 11 K and a relative cooling power (RCP) of 209.4 J kg−1 at 5 T applied field. While ErCr0.75Al0.25O3 show a maximum magnetic entropy of 11.52 J kg−1 K−1 at 11 K with a 5 T applied field and RCP of 186.66 J kg−1, whereas ErCr0.5Al0.5O3 displayed −ΔSMmax of 11.63 J kg−1 K−1 at 5 K with a 5 T applied field and RCP value of 160.78 J kg−1. The results show that nonmagnetic doping, such as Al3+, could maintain the compound’s magnetocaloric property to an extent.
Role of interdiffusion on the magnetism of ultrathin LaMnO3 films
Authors: Stramaglia F. , Panchal G. , Nolting F. , Vaz C. A. F.
Published: February 2024

We present a detailed study of the magnetic, spectroscopic and structural properties of ultrathin LaMnO3 films deposited on SrTiO3(001) substrates by oxide molecular beam epitaxy. We find that the as-grown LaMnO3 films are slightly reduced and present a significant magnetic moment, while annealing to 600 °C fully oxidizes and enhances its magnetic properties. From synchrotron x-ray photoemission spectromicroscopy, we find the presence of Sr, Ca and Si in the LaMnO3 film that diffuse from the SrTiO3 substrate; these impurities act as hole dopants, and can explain the presence of ferromagnetism in LaMnO3. This work highlights the importance of cation mobility at the elevated growth temperature in modifying the magnetic properties of ultrathin LaMnO3 films.
Thickness dependent structural, morphological, and magnetic properties of PLD grown CoFe thin film
Authors: Kumar Prashant , Kumar Ravi , Sharma Vipul , Khanna Manoj Kumar , Kuanr Bijoy Kumar
Published: February 2024

The objective of the present investigation is to optimize the thickness of Pulse Laser Deposition (PLD)-grown CoFe thin films to achieve minimal effective Gilbert damping (αeff) for potential spintronics applications. The effect of the thickness (5-30 nm) of CoFe ultra-thin films on the Si/SiO2 substrate on the structural, morphological and magnetic properties has been reported. The X-ray diffraction (XRD) peak at 44.5° shows the growth of CoFe along the (110) crystal plane. A nearly square M-H loop with high saturation magnetization (Ms) suggests good crystalline growth of CoFe film. A high coercive field (Hc) observed in the thinnest 5 nm film is due to defects such as dislocations and stacking faults that appear at very low thickness. These defects gradually decrease with an increase in CoFe film thickness, as evident from a decrease in the Hc and an increase in the Ms. The value of αeff is largest for the thinnest 5 nm film due to defects and magnetic inhomogeneities present at this thickness. The damping is reduced by approximately one-third for the 10 nm thin film in comparison to the 5 nm film, which signifies a good quality film with fewer disorders.
Integration of fiber tracts in anatomically accurate brain models during transcranial magnetic stimulation
Authors: Lewis Connor J. , Harris Connor M. , Mittal Neil , Peterson Carrie L. , Hadimani Ravi L.
Published: February 2024

Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique used in the treatment of several neurological conditions. The dosage parameter for TMS protocols is the resting motor threshold (RMT) which has been shown to vary between participants with limited understanding. The goal of this study was to investigate how white matter-derived fiber tracts integrated into finite element analysis simulations influence TMS response in the form of RMT. Ten healthy participants were included in this study who underwent TMS, diffusion tensor imaging, and structural magnetic resonance imaging. Anatomically accurate head models were created, and fiber tracts were extracted from Diffusion tensor imaging and integrated into these head models before finite element analysis simulations were performed to model the effects of empirical TMS. Linear mixed effects models were used to evaluate how the induced electric field strength on the fiber tracts (EFSTract) influenced RMT. We found the induced electric field strength along fiber tracts did influence RMT, however the effect of this relationship on RMT is not clinically relevant due to its small magnitude. This suggests finite element analysis of the fiber tracts is not meaningful when tracts are considered a homogenous material and thus lacking physiology. However, tractography provides a valuable framework within which to organize physiological models of signal transmission, and it is likely a combination of this approach with more physiologically detailed modeling would provide more accurate RMT prediction.
Size dependence of domain wall mediated switching dynamics of perpendicular magnetic tunnel junctions in the presence of reference layer stray field
Authors: Nisar Arshid , Kaushik Brajesh Kumar , Pramanik Tanmoy
Published: February 2024

Recent investigations on spin-transfer-torque-induced switching dynamics of perpendicular magnetic tunnel junctions (MTJ) have revealed different switching anomalies. Here, the influence of stray field from a synthetic anti-ferromagnet (SAF) based reference layer on the domain wall (DW) mediated switching of the free-layer magnet is studied via finite temperature micro-magnetic simulations for varying MTJ diameters. For larger diameters (∼80 – 120 nm), a stray field gives rise to persistent back-and-forth oscillation of the unswitched domain, delaying the switching process and causing increased write errors. For smaller diameters (∼30 – 56 nm), quasi-coherent switching occurs, as expected. For the intermediate ranges of MTJ diameters (∼60 – 70 nm), another switching mode emerges where a bubble-like feature is observed to evolve during the switching process, causing a very rapid change in magnetization. These paths are observed to originate from DWs partly in Bloch and partly in Néel configuration. We find that at the intermediate ranges of device size, the stray field becomes stronger for a given SAF configuration, and the energy difference between the Néel and Bloch configurations is also lowered. Hence, a stronger stray field could easily distort the DW propagation in the Walker breakdown regime, leading to such magnetization behavior. Our findings present interesting insights into DW-mediated switching modes in perpendicular MTJ structures caused by unoptimized stray fields from the SAF.
Temperature-dependent hysteresis model based on temporal convolutional network
Authors: Zhang Hao , Yang Qingxin , Zhang Changgeng , Li Yongjian , Chen Yifan
Published: February 2024

The variation of temperature modifies the magnetic behavior of ferromagnetic cores which may affect the performance of electrical equipment. Therefore, it is imperative to develop a temperature-dependent hysteresis model to precisely calculate electromagnetic characteristics of electrical equipment. In this paper, a Temporal Convolutional Network (TCN) in combination with the Play operator is developed. The proposed model incorporates the temperature-dependent spontaneous magnetization intensity as the model input to introduce the temperature effect. To enhance the accuracy of model training outcomes, the Bayesian optimization approach for automatically selecting network model parameters is provided. The results show that the proposed model can accurately predict the hysteresis characteristics of materials under varying temperature and frequency conditions.
Magnetoelectric CoV2O6—Role of Fe inter-play in Co-based Ising spin chain interactions
Authors: Meher K.R.S. Preethi , Maignan Antoine , Pelloquin D. , Simon Ch.
Published: February 2024

CoV2O6, a Brannerite-type material, exists in both monoclinic (α) and triclinic (γ) forms. α- CoV2O6 exhibits quasi-1D ferromagnetic chains of octahedrally-coordinated Co2+ions in the higher spin state. Fe2+ doped α-CoV2O6 (3 mol%) single crystals were synthesized using high temperature melt method. The motivation is to investigate whether disruption of 1D Co2+ ferromagnetic chains by small Fe3+ substitution alters the antiferromagnetic ground state and lead to stronger spin-frustration. In this paper, we report the magnetic and magnetodielectric properties of Fe doped α-CoV2O6 in detail. The strongly anisotropic nature of magnetic and magnetodielectric characteristics were captured well in the data through orientation dependent measurements with H being parallel to a and c axes of the crystal. Relative dielectric permittivity (εr) exhibited sharp peaks coinciding with the plateau edges Hc1 ∼2.2 T and Hc2 ∼4.4 T in the magnetization curves (M-H) for applied H parallel to a-axis. For dielectric measurements under applied H parallel to c-axis, relative dielectric permittivity exhibited sharp peak around Hc2 ∼3.1 T, again coinciding with the M-H behavior. Such closely related magnetic field induced dielectric transitions reflected in both M(H) and εr(H) measurements is a rare phenomenon and representative of strong spin-lattice coupling in this phase.
Equilibrium and locomotion characteristics of multi-modular magnetic millirobots with different magnet patterns
Authors: Lee Y. , Jeon S.
Published: February 2024

This paper investigated a multi-modular magnetic microrobot/millirobot (MMM) with a serial chain structure consisting of multiple identical modules. Depending on the magnet pattern used for the MMM’s modules, an MMM can have different equilibrium postures under an external magnetic field, such as assembled ring and disassembled straight-line postures. In this study, we investigated the equilibrium and locomotion characteristics of the MMM by applying two different representative magnet patterns, considered to be effective for magnetic actuation, to the robots. We established various equations to determine and control the assembly, disassembly, and locomotion of the MMM with each magnet pattern. We also conducted various experiments demonstrating the assembly, disassembly, and cargo delivery capabilities of the MMM under different external magnetic fields. Results confirmed that each MMM and their magnet pattern have distinctive and useful characteristics, demonstrating that the two magnet patterns can be selectively and effectively used as MMM in different applications.
The Fine-grained Structure of the Lexical Area
Authors: Fábregas Antonio
Published: February 2024

This is the first book that presents a complete description and analysis of the Spanish suffixes that alter the grammatical behaviour of nouns and adjectives without changing their grammatical category, supporting a fine-grained decomposition of the syntactic area where these word classes are defined.

In this monograph the reader will find a detailed empirical description of suffixes for gender, mereological properties of nouns, scalar properties of adjectives and a variety of nominal suffixes expressing actions, measures or locations, as well as an integral Neo-Constructionist analysis of the syntactic structure of the resulting formations. Framed within a Nanosyntactic-oriented framework, this book sheds light on the nature of lexical categories and the components of the low syntactic structure of nouns and adjectives. The book will be useful both to researchers in Spanish linguistics or theoretical morphology and to advanced students of Spanish interested in learning more about the expressive devices that nouns and adjectives allow.
“Ding ding ding we have a hypocrite!”
Authors: Tanskanen Sanna-Kaisa
Published: February 2024

This study approaches verbal hypocrisy from a metapragmatic perspective, arguing that our understanding of
hypocrisy as a pragmatic phenomenon benefits from an analysis of how language users negotiate hypocrisy in actual
interaction. The goal is to uncover what kinds of statements participants in online discussions perceive as verbal
hypocrisy, how they react to it and how they discuss it. Participants’ claims of hypocrisy are regarded as evaluative
metapragmatic acts, with which they make visible their assessment of language use as hypocritical. The analysis of the
claims in their context reveals that claims are made in situations of perceived double standards or misalignment.
Reactions to claims of hypocrisy range from resistance and negotiation to silence. Furthermore, the negotiation of
hypocrisy involves considerations of intention and accountability.
Apology as hypocrisy
Authors: Halmari Helena
Published: February 2024

Apologies have been a rewarding target for research in the pragmatics tradition; however, few studies
connect apologies to hypocrisy. This chapter is an attempt to do so. I approach the pragmalinguistic aspects of
hypocrisy by examining two notorious apologies: Clinton’s 1998 apology for his Monica Lewinsky affair and Trump’s 2016
apology for his vulgar comments about women. I argue that hypocritical apologies can be identified via an analysis of
felicity conditions (including the speakers’ motivations and intentions) and move structures. Clinton’s and Trump’s
apologies share most features with non-hypocritical apologies, but they also include self-promotional and accusatory
moves toward the end of the speech event which are absent from genuine apologies. These extra moves turn their
apologies into hypocritical ones.
An epilogue and note on cross-cultural hypocrisy
Authors: Culpeper Jonathan
Published: February 2024

This chapter very briefly comments on some of the chapters of this volume, and then focuses on what has not
been covered: hypocrisy across cultures (and languages). With a particular focus on British English and culture, it
notes synchronic contrasts, specifically with Israeli “dugri” speech, and diachronic contrasts, from the mediaeval
period to today. It argues that Haugh’s (Chapter 7, this volume) notion of
“sincere hypocrisy” is key to British English politeness. Finally, it reminds readers of how “sincere hypocrisy” fits
the range of hypocrisy types, and finishes with a re-statement of Sorlin and Virtanen’s (Chapter 2, this volume) pragmatic definition of hypocrisy.
Study of deformation behavior of plastic metal materials during laser-assisted micro-imprinting formings
Authors: Meng Siwei , Shi Guangfeng , Lv Hongbing
Published: February 2024

When a large taper angle diamond taper indenter is used for micro-imprinting plastic metals, the stagnation zone is caused by excessive extrusion and friction within the material at the tip of the indenter, which in turn affects the flow characteristics of the material and the quality of the processed surface. In this study, the formation of laser-assisted diamond indenter micro-imprinting stagnation zone mechanism was proposed. The deformation behavior when processing plastic-metal materials using this technique is revealed by numerical simulation. And observed this phenomenon through the hardness distribution of the micro tapered hole cross-section. The results show that when the taper angle of the diamond indenter is greater than 105°, a significant stagnation zone occurs in the material. The initial morphology is jug-shaped, showing periodic changes due to the hard substrate. The average hardness in this region is 91.5 HV, which is significantly lower than the rest of the material. When P = 30 W, the height of the stagnation zone is reduced by 43 μm and the first presence time is extended by 90 μm. The reduction in the friction coefficient leads to a reduction in the width of the interfacial stagnation zone.