bluuebunny/crossref_metadata_2025 huggingface dataset:
“Co-properties” of the nonlinear semi-group on L∞ generated by a scalar conservation law with p–Laplacian viscosity
Authors: Liu Yechi
Published: January 2025

This paper concerns properties of solutions to the Cauchy problem of scalar conservation law with p–Laplacian viscosity. We firstly prove the existence and uniqueness of solution with L∞ initial data, and give uniform estimates of the solution and its derivative. Then, we use these estimates to prove that the semi-group on L∞, generated by the solution map, satisfies the properties of comparison, contraction, conservation and constants, which are called “Co-properties.” “Co-properties” can be used to study the large time stability of solutions to the equation.
Universal finite-time scaling in the transcritical, saddle-node, and pitchfork discrete and continuous bifurcations
Authors: Corral Álvaro
Published: January 2025

Bifurcations are one of the most remarkable features of dynamical systems. Corral et al. [Sci. Rep. 8(11783), 2018] showed the existence of scaling laws describing the transient (finite-time) dynamics in discrete dynamical systems close to a bifurcation point, following an approach that was valid for the transcritical as well as for the saddle-node bifurcations. We reformulate those previous results and extend them to other discrete and continuous bifurcations, remarkably the pitchfork bifurcation. In contrast to the previous work, we obtain a finite-time bifurcation diagram directly from the scaling law, without a necessary knowledge of the stable fixed point. The derived scaling laws provide a very good and universal description of the transient behavior of the systems for long times and close to the bifurcation points.
Orbits of families of discrete dynamical systems evolving in the natural numbers
Authors: Campos Cantón Eric
Published: January 2025

In this paper, we give a class of one-dimensional discrete dynamical systems with state space N+. This class of systems is defined by two parameters: one of them sets the number of nearest neighbors that determine the rule of evolution, and the other parameter determines a segment of natural numbers Λ={1,2,…,b}. In particular, we investigate the behavior of a class of one-dimensional maps where an integer moves to an other integer given by the sum of the nearest neighbors minus a multiple of b∈N+. We find the coexistence of fixed points and periodic cycles. Two single parameter families of maps are introduced and their dynamics in the segment of natural sequence Λ. Furthermore, an order of the numbers of the set Λ−b is given by these families. Last, we present a connection of the N+ generated by the orbits of a particular case.
Dielectric reliability and interface trap characterization in MOCVD grown in situ Al2O3 on β-Ga2O3
Authors: Roy Saurav , Bhattacharyya Arkka , Peterson Carl , Krishnamoorthy Sriram
Published: January 2025

In this article, we investigate the in situ growth of Al2O3 on β-Ga2O3 using metal-organic chemical vapor deposition at a high temperature of 800 °C. The Al2O3 is grown within the same reactor as the β-Ga2O3, employing trimethylaluminum and O2 as precursors without breaking the vacuum. We characterize the shallow and deep-level traps through stressed capacitance–voltage (C–V) and photo-assisted C–V methods. The high-temperature deposited dielectric demonstrates an impressive catastrophic breakdown field of approximately 10 MV/cm. Furthermore, we evaluate the reliability and lifetime of the dielectrics using time-dependent dielectric breakdown measurements. By modifying the dielectric deposition process to include a high-temperature (800 °C) thin interfacial layer and a low-temperature (600 °C) bulk layer, we report a 10-year lifetime under a stress field of 3.5 MV/cm along a catastrophic breakdown field of 7.8 MV/cm.
Sustainable energy optimization in dual-area systems: Integrating floating solar with hydroelectric power using hCIGWO and advanced 2-DOF controllers
Authors: Gupta Rohan Kumar , Shankar Ravi , Kumar Amitesh
Published: January 2025

Integrating floating solar panels with hydroelectric power creates a sustainable energy solution, leveraging water-based resources for enhanced efficiency and environmental benefits. To optimize these systems, the hybrid Circle-Inspired Gray Wolf Optimization algorithm, combined with a hybrid two-degree-of-freedom proportional integral derivative controller cascaded with fractional order type integral controller and proportional integral controller (2-DOF PIDFOI-PI), addresses frequency stabilization challenges due to the lack of natural inertia in renewable sources. This dual-area system, featuring diverse renewable sources and Energy Storage Systems, mitigates the intermittent impact of renewables on frequency regulation. The proposed method outperforms optimization techniques like hybrid particle swarm optimization and Gray wolf optimization (hPSO&GWO), African Vulture optimization algorithm, and Gray Wolf Optimization (GWO) across five cases, reducing settling time by up to 81% and error by 0.5%–46%. The projected model with the controller is validated through stability analysis, which gives a stable system. This model can be applied to the Omkareshwar Hydroelectric facility, including a 600 MW floating solar project, enhancing system performance through innovative control and optimization.
Observing quantum coherent oscillations in a three-level atom via electromagnetically induced transparency by two-dimensional spectroscopy
Authors: Jin Jing-Yi-Ran , Zhang Hao-Yue , Yao Yi-Xuan , Chen Rong-Hang , Ai Qing
Published: January 2025

Two-dimensional electronic spectroscopy (2DES) has high spectral resolution and is a useful tool for studying atomic dynamics. In this paper, we show a smallest unit of electromagnetically induced transparency (EIT) for 2DES, i.e., a three-level system. It is found that the original main peak is split into four small ones due to the introduction of EIT. It suggests that the homogeneous broadening of 2DES can be effectively reduced by EIT. Moreover, in sharp contrast to a constant height, the height of the peaks will manifest a damped oscillation with respect to the population time. It seems that the quantum-beat phenomenon appears. These findings may help us obtain more information about the dynamics of excited states.
Simulation of oxygen and carbon impurity transport during magnetically controlled Czochralski silicon growth
Authors: Zhang Wenyong , Gao Dedong , Wang Shan , An Yan , Wu Haohao , Lin Haixin , Hou Lin
Published: January 2025

This study establishes a multi-field coupling model that includes a thermal field, flow field, oxygen and carbon impurity concentration field, and magnetic field, focusing on controlling the transport of oxygen impurities at the free surface of the melt. The effects of cusp magnetic field introduction, argon inlet flow velocity, and furnace pressure on the transport of oxygen and carbon impurities are analyzed, and the concentration field distribution of oxygen and carbon impurities within the furnace at the equal-diameter stage (300 mm) under different parameters is obtained. The results show that the method combining the cusp magnetic field with adjustments in furnace pressure and argon flow velocity can significantly reduce the oxygen concentration in the melt below the crystal and effectively expel oxygen and carbon impurities, providing optimization references for applying cusp magnetic fields and reducing oxygen and carbon impurities in the melt for large-sized Czochralski single-crystal silicon.
Control of structural phase transition and energy storage behavior through cooling rate in (Bi0.5Na0.5)TiO3–BaTiO3 ceramics
Authors: Ohshima Yuri , Ochiai Yuta , Takagi Yuka , Nam Hyunwook , Nagata Hajime
Published: January 2025

In lead-free (Bi0.5Na0.5)TiO3–BaTiO3 (BNT–BT) ceramics, the BNT-rich side has R3c ferroelectric domains at room temperature, and modulated P4bm tetragonal nanodomains develop within the R3c rhombohedral phase at approximately the depolarization temperature Td. Such structural phase transitions have conventionally been modulated by doping with additives or by controlling the composition. However, it is considered that the coexistence region between the R3c and P4bm phases is important for enhancing the energy storage behavior because the phase reversal between them, caused by the electric field, can cause the BNT-based ceramics to exhibit an antiferroelectric-like pinched hysteresis loop. In this study, the structural phase transition of BNT–BT ceramics is promoted through process control, that is, by adjusting the cooling rate, and then the stabilization of the P4bm phase and the expansion of the coexistence region of the R3c and P4bm phases were examined, which results in enhanced energy storage behavior. Consequently, BNT–BT ceramics prepared at a slower cooling rate (0.01 °C s−1) than that of normal firing (0.05 °C s−1) demonstrate the stabilization of the P4bm phase and expansion of the coexistence region of the R3c and P4bm phases. Therefore, process control modulates the structural phase transition, which can cause enhanced energy storage behavior.
Twinning and strain induced modifications in insulator-metal transition and large magnetoresistance in La0.67Ca0.33MnO3 films
Authors: Mohan Brij , Manral Pooja , Chander Parvesh , Singh H. K. , Malik V. K.
Published: January 2025

The physical characteristics of epitaxially sputtered La0.67Ca0.33MnO3 (LCMO) films are modified by twinning when deposited on different single crystal substrates at varying thicknesses. Comprehensive high-resolution x-ray diffraction measurements reveal the formation of two types of tilted domains, whose influence becomes prominent in rocking curve scans with increasing thickness. The occurrence of twinning is attributed to the shear strain relaxation process that accommodates the lattice symmetry mismatch between the film and the substrate. In the electrical transport properties of thicker films, the effect of twinning manifests as a broadening of the insulator–metal transition in resistance–temperature (R–T) plots, in which an extra hump emerges. This broadening effect is also noticeable in magnetoresistance curves, leading to a large magnetoresistance spread over a broad temperature range. While the additional hump in R–T plots vanishes under stronger magnetic fields, the persistent broadening of the transition and magnetoresistance suggests that twinning continues to influence the film properties even at higher field strengths. Thick LCMO films exhibit similar broadening in the transition from the paramagnetic to ferromagnetic phase with an additional transition during magnetic (M–T) measurements. In contrast, LCMO films of lesser thickness display sharp electrical and magnetic transitions without significant evidence of any supplementary transition. These results suggest that the twinning effect in films, caused by substrate-induced strain relaxation, can profoundly alter the transport properties of these functional films and substantially widen the temperature range where maximum magnetoresistance is observed.
Non-ionizing cross section of electron scattering on atoms in matter accounting for dynamical screening effect
Authors: Medvedev N. , Zainutdinov D. I. , Volkov A. E.
Published: January 2025

We present a model of non-ionizing scattering of electrons on atomic ensemble in matter, applicable in a wide electron energy range from ∼eV up to relativistic ones. The approach based on the dynamic-structure factor formalism considers collective response of the atomic and electronic systems of a target. It accounts for dynamical screening of atomic nuclei in matter by valence (collective) and core–shell electrons during the scattering events, dependent on the incident electron velocity. The proposed formalism for the cross section enables us to describe in a unified manner the electron scattering on the ensemble of isolated atomic nuclei at high incident electron energies, reducing to the scattering on phonons with a decrease in the energy. Our model can be used, e.g., in transport Monte Carlo codes to describe the energy exchange between excited electrons and atomic ensemble in matter. An example of swift heavy ion track formation in quartz simulated with the proposed cross section shows reasonable agreement with the experiment validating the model.
Visualization of the phonon evolution behavior in NaNbO3 single crystal during field-induced phase transition by in situ Raman spectroscopy
Authors: Wang L. G. , Jiang X. L. , Zhu C. M. , Yu G. B. , Su X. F. , Qin M. Y. , Lu S. , Shen N. , Zheng X. X.
Published: January 2025

NaNbO3 (NN) is a significant lead-free alternative for pulse power systems or nonvolatile memories due to its antiferroelectric P phase at room temperature. However, a comparable free energy between P phase and another ferroelectric Q phase leads to an irreversible transition from P to Q phase just under a weak electric field, which results in the unobservable double hysteresis loops. In addition, recent studies reveal that the critical field needed during the transition process is inconsistent between in situ microstructure characterization and macroscopic polarization measurement. Consequently, the intricate field-induced phase transition in NN is perplexing. Based on high sensitivity of Raman spectroscopy to symmetry breaking in lattices, this work systematically investigates the in situ Raman spectra of NN single crystals, analyzing the evolution and depolarization behavior of various phonons under an electric field. Correspondingly, the transition from P to Q phase is determinately identified, accompanied by in-depth understanding of the phonon dynamics of field-induced phase transition. This present work provides a reliable experimental foundation for further probing on the transition mechanism of ferroelectric/antiferroelectric order in dielectrics, as well as facilitating the performance control and application development of NN-based devices.
Exact solutions and classification of linearized eigenvalue problems for one-dimensional Gross–Pitaevskii system
Authors: Fazly Mostafa , Miyamoto Yasuhito
Published: January 2025

We derive exact solutions for a one-dimensional Gross–Pitaevskii system with Neumann boundary conditions using Jacobi elliptic functions. Additionally, we investigate the classical linearized eigenvalue problem for this system, providing three exact special eigenpairs and determining asymptotic formulas for the eigenvalues. This leads to a classification of the eigenvalues and eigenfunctions.
Model and algorithmic augmentation in phase field method for simulating the pool boiling phenomenon with high-density ratio
Authors: Zhang Xiao-Yu , Duan Xin-Yue , Zhang Tao , Xu Ming-Hai , Sun Shuyu , Gong Liang , Liu Lande
Published: January 2025

Although the dynamic van der Waals model has great potential in numerically simulating pool boiling, it is still limited to low liquid–vapor density ratios (about 10:1) due to the inherent thermodynamic inconsistency. This study proposes a thermodynamic consistency simplified dynamic van der Waals model to simulate pool boiling with large liquid–vapor density ratios. This model is based on the thermodynamic relationship associating the gradients of temperature and generalized chemical potential with the divergence of the reversible viscous stress tensor. A novel semi-discrete numerical algorithm that satisfies the thermodynamic consistency for this mathematical model is also proposed. The numerical results exhibit excellent agreement with that of analytical, validating the effectiveness and applicability of the proposed model for vapor–liquid coexistence. Compared to the original dynamic van der Waals model, the proposed model and algorithm can effectively reduce the spurious velocity at the vapor–liquid interface, breaking the limitations of low-density ratio and leading to stable simulation at higher-density ratios under low saturation temperatures. The approach is used to model pool boiling at low saturation temperatures with different wettability and liquid–vapor density ratios, and the saturation temperature significantly lower than reported in comparable literature (as low as 0.45Tc and the liquid–vapor density ratio is about 225:1). Compared to low liquid–vapor density ratios, larger liquid–vapor density ratios inhibit bubble coalescence, thereby suppressing the formation of large bubbles. In addition, larger density ratios more effectively maintain the shape of bubbles.
Mitigation of abnormal vibration on high-speed trains under unsteady aerodynamic loadings using bogie skirts
Authors: Li Yifan , Li Tian , Zhang Jiye
Published: January 2025

As train speeds increase and operating environments diversify, the issue of abnormal vibration of tail car in high-speed train has become a significant threat to operational stability and safety. In this study, numerical simulation was employed to develop aerodynamic and multi-body dynamics models for 3-car and 8-car train formations. Using the proper orthogonal decomposition method for reduced-order analysis, the research has examined the unsteady flow field distribution, surface pressure, and aerodynamic performance of the train cars at speeds of 200, 300, and 400 km/h, and the aerodynamic optimization was achieved by installing bogie skirts to improve the vehicle stability. The results indicate that the pressure fluctuation regions contributing to lateral aerodynamic loadings vibration are concentrated on the sidewalls near the bogie cabins at heights of z = 0.0 m to 0.8 m. The installation of bogie skirts optimizes the pressure mode distribution and the amplitude of temporal coefficients at these locations, effectively reducing the intensity of lateral aerodynamic loadings. Additionally, the main frequency of the loadings has been increased, thereby avoiding the possibility of resonance caused by aerodynamic loadings frequencies approaching the vehicle suspension's natural frequency. Across all three speed levels, varying degrees of tail car stability improvement were observed. In particular, at 400 km/h, the lateral and vertical Sperling indices were reduced by 6.96% and 9.41%, respectively, effectively mitigating the abnormal vibration in the tail car of long-formation trains caused by aerodynamic loadings during operations.
The wake enhancement effect of bionic grooved blade on low-specific-speed centrifugal pump
Authors: Ke Qidi , Liu Yingqian , Tang Lingfeng , Wang Aijun , Fu Qiang , Li Huairui , Su Haonan , Han Chen
Published: January 2025

Water conveyors are important infrastructure supporting industrial, agricultural, and urban development. They provide a stable source of water for factories, farmland, and residential areas. As critical high-head water transportation devices, low-specific-speed centrifugal pumps frequently encounter flow separation at the trailing edges of their blades, adversely impacting hydraulic performance. To alleviate this problem, this study introduces a biomimetic Space-V groove at the trailing edge of the impeller, grounded in the second vortex theory. Computational fluid dynamics simulations were performed utilizing the shear stress transport K-ω turbulence model to analyze the flow field within the impeller domain. The Q criterion was employed to identify vortex cores and assess turbulence kinetic energy, while comparing the hydraulic performance and pressure pulsations of the centrifugal pump before and after the modification. The results indicate that, at the rated flow rate, the optimized biomimetic grooved impeller achieves approximately a 3% increase in head and a 5% increase in efficiency. Furthermore, the distribution of vortex cores at the outlet of the flow channel is also alleviated. Experimental validation confirmed that the biomimetic model enhances the flow conditions at the impeller trailing edge. This study serves as a reference for blade design in low-specific-speed centrifugal pumps.
Imprinting of stochastic magnetic domain configurations by fluctuating interlayer coupling
Authors: Ma Mangyuan , Zhao Le , Jiang Wanjun
Published: January 2025

Competing interaction within magnetic materials leads to the formation of complex magnetic domain configurations such as stripe domains, labyrinthine domains, magnetic bubbles, and skyrmions, which are fingerprints of different magnetic materials. An effective tailoring of these competing interactions and the resultant magnetic domain configurations by extrinsically means is of current interest. Through depositing an interfacially asymmetric Ta/CoFeB/MgO/Ta multilayer on a rare-earth-doped yttrium iron garnet of composition SmLu: YIG film, we show that the magnetic domain configurations from the bottom SmLu: YIG film can be partly imprinted onto the top Ta/CoFeB/MgO/Ta multilayer. The formation of stochastic domain configurations, such as labyrinthine domains, parallel stripe domains, and magnetic bubbles in the Ta/CoFeB/MgO/Ta multilayer, is jointly studied by using polar magneto-optical Kerr effect microscope and anomalous Hall effect measurements. The underlying physics is attributed to the fluctuating interlayer dipole–dipole interaction that results in the partial imprinting, which could substantially modify the intrinsic magnetism of the top Ta/CoFeB/MgO/Ta multilayer and leading to the formation of stochastic domain configurations. Our results provide an effective approach for tailoring the competing interaction in magnetic materials and for application scenarios in which the formation of stochastic domain configurations is required.
Koopman learning with episodic memory
Authors: Redman William T. , Huang Dean , Fonoberova Maria , Mezić Igor
Published: January 2025

Koopman operator theory has found significant success in learning models of complex, real-world dynamical systems, enabling prediction and control. The greater interpretability and lower computational costs of these models, compared to traditional machine learning methodologies, make Koopman learning an especially appealing approach. Despite this, little work has been performed on endowing Koopman learning with the ability to leverage its own failures. To address this, we equip Koopman methods—developed for predicting non-autonomous time series—with an episodic memory mechanism, enabling global recall of (or attention to) periods in time where similar dynamics previously occurred. We find that a basic implementation of Koopman learning with episodic memory leads to significant improvements in prediction on synthetic and real-world data. Our framework has considerable potential for expansion, allowing for future advances, and opens exciting new directions for Koopman learning.
Investigation of ferrofluid flow between torsionally oscillating disks
Authors: Singh Kuldeep , Kumar Rakesh
Published: January 2025

The ferrofluid flow between torsionally oscillating disks spans a spectrum of applications including enhanced damping, controlled energy dissipation, magnetic actuators, cooling systems, and advanced aerospace engineering. The current study focuses on exploring ferrofluid flow between torsionally oscillating disks under two selected cases: Case I, where the lower disk torsionally oscillates, while the upper disk remains stationary, and Case II, where both the upper and lower disks torsionally oscillate, with the upper disk 180° out of phase relative to the lower disk. The novel influence of magnetic field-dependent (MFD) viscosity and variable thermal conductivity are incorporated into the dealing equations of the ferrofluid flow to identify the real character of ferrofluids. The parametric form of these equations is obtained after utilizing the suitable similarity function approach. The patterns of the velocity field, streamlines, and isotherms along with velocity and temperature variations are portrayed pictorially after a series of experimental simulations conducted in the MATLAB environment by using Bvp5c. The variations in the coefficients of skin friction and Nusselt numbers at the respective upper and lower disks are displayed through graphs and tables with the emerging parameters. It is identified from the comparative analysis of above-mentioned two cases that the ferrofluid flow is a decreasing function of the MFD parameter due to the reduced magnitude of velocity, whereas a direct relationship between the ferrofluid temperature and the MFD parameter is noted. It is also observed that ferrofluid heat is enhanced by the variable thermal conductivity owing to the increased value of the ferrofluid temperature. This study may be helpful in understanding magnetically damped oscillations.
Electride transition in liquid aluminum under high pressure and high temperature
Authors: Qin Yuxin , Zhang Xiaoliang , Zhou Shiting , Wang Yangyang , Chen Gaoyuan , Dai Chen-Min , Li Weiwei , Li Cong
Published: January 2025

Despite the conventional view of liquid aluminum (l-Al) as a simple metal governed by the free-electron model, it exhibits unique bonding characteristics. This study uncovers a gradual transition from free electron to electride behavior in l-Al at high pressure and temperature, forming a type of two-component liquid where atomic and electride states coexist. The proportion of electride increases with pressure and temperature until reaching saturation, leading to notable changes in the pair-correlation function and coordination number of l-Al at saturation pressure. Furthermore, this electride transition was found to profoundly impact the thermodynamic and dynamic properties, as evidenced by anomalous crossovers in the isothermal bulk modulus, thermal expansivity, heat capacity, sound speed, and self-diffusion coefficient correlated with varying pressure and temperature. The finding of the anomalous behavior of l-Al described in this work will deepen our understanding of the electronic structure and also lay ground work for interpreting and predicting new physical and chemical behavior under extreme conditions.
Impact of key airfoil blade parameters on the internal flow and vibration characteristics of centrifugal pumps
Authors: Jia Xiaoqi , Zhang Jie , Chen Denghua , Tang Zhenhe , Huang Qing , Zhou Chengming , Ma Yongtao , Zhao Qigang , Lin Zhe
Published: January 2025

Pressure pulsations and transient fluid forces resulting from unstable internal flow can significantly impact the vibration performance and operational stability of centrifugal pumps. This study delves into the influence of key parameters like airfoil blade thickness, outlet angle, and curvature on the internal flow dynamics and vibration characteristics of these pumps. The research highlights how variations in airfoil blade parameters primarily affect the mid-to-rear regions of the impeller and the volute flow region. By optimizing the outlet angle of the airfoil blades, the curvature radius of the pressure side profile, and the maximum blade thickness within a specified range, the study demonstrates a reduction in flow velocity at the impeller outlet, alteration of flow direction, and mitigation of vertical fluid impact on the volute casing wall. These adjustments effectively decrease the strength and quantity of unstable vortex structures within the pump, leading to a more stable flow regime. Consequently, this optimization minimizes rotor–stator interaction effects within the pump, resulting in decreased pressure pulsations and fluid forces on the volute casing wall, thereby reducing vibration levels. However, deviations from optimal parameters, such as outlet angle coefficient A < 0.46, pressure side profile curvature radius coefficient B < 0.53, and maximum blade thickness coefficient C > 0.11, can lead to an uneven distribution of blade loads, increased radial forces, vorticity at the tongue, and pressure pulsations, ultimately compromising the operational stability of the pump.
Investigation on effects of vibration amplitude and frequency in vibration-assisted cutting of stainless steel SUS304
Authors: Shi Mang , Li Xiaoye , Zhang Jicheng
Published: January 2025

Vibration-assisted cutting (VAC) has been proved as an efficient process to machine difficult-to-cut materials, and vibration amplitude and vibration frequency are the main parameters that significantly affect the work of the VAC process. This paper investigated the effects of vibration amplitude and frequency in machining of SUS304 by the VAC process considering continuous cutting. With the help of the FE analysis method, the cutting force and its amplitude, as well as cutting temperature, were calculated and compared to evaluate the quality of the VAC process. Results show that the largest cutting force and the cutting temperature can be reduced with the increase in vibration amplitude and frequency, which is beneficial for the life of the tool. This is mainly induced by optimization of the chip during the VAC process. A higher feeding depth will lead this tendency to be less significant. The vibration amplitude should be 0.5–0.7 times the feeding depth due to the work of the instantaneous feeding speed. On the other hand, the cutting force amplitude will increase along with the vibration amplitude, and this will lead to reliability problems of tools and workpieces. The vibration amplitude and frequency based on their effect on cutting temperature and cutting force amplitude needs to be studied.
The alchemical integral transform revisited
Authors: Krug Simon León , Anatole von Lilienfeld O.
Published: January 2025

We recently introduced the Alchemical Integral Transform (AIT), enabling the prediction of energy differences, and guessed an ansatz to parameterize space r in some alchemical change λ. Here, we present a rigorous derivation of AIT’s kernel K and discuss the parameterization r(λ) in n dimensions, i.e., necessary conditions, mathematical freedoms, and additional constraints when obtaining it. Analytical expressions for changes in energy spectra and densities are given for a number of systems. Examples include homogeneous potentials such as the quantum harmonic oscillator, hydrogen-like atom, and Dirac well, both for one- and multiparticle cases, and a multiparticle system beyond coordinate scaling for harmonic potentials.
Field-free spin–orbit switching of canted magnetization in Pt/Co/Ru/RuO2(101) multilayers
Authors: Wu Yunzhuo , Wu Tong , Chen Haoran , Cui Yongwei , Xu Hongyue , Jiang Nan , Cheng Zhen , Wu Yizheng
Published: January 2025

Achieving field-free current-induced switching of perpendicular magnetization is crucial for the advancement of spin–orbit torque magnetic random access memory technology. In our study on the Pt/Co/Ru/RuO2(101) system, we have demonstrated field-free switching via current injection along the RuO2[010] axis. We found that the system features a tilted easy axis, deviating from the out-of-plane orientation toward the RuO2[1¯01] direction. The application of current perpendicular to this tilted axis generates a significant out-of-plane effective field, enabling field-free magnetization switching. Our findings also suggest that fine-tuning the thickness of the Ru layer to change the tilt angle can substantially reduce the critical switching current density. This work offers a promising approach for controlling the tilting magnetization, which is vital for the development of RuO2-based magnetic devices.
Creation of hyperoxia superconducting phase in La2CuO4 by applying shear strain under high-pressure compression
Authors: Mito Masaki , Abe Wasuke , Yamamoto Katsumi , Tajiri Takayuki , Horita Zenji
Published: January 2025

We successfully stabilized the hyperoxia superconducting phase of La2CuO4, the parent insulating compound of La-based cuprate superconductors, by applying compression under high pressure and successive shear strains via the process of high-pressure torsion (HPT). Superconducting phases in the La2CuO4 system are created via the hole doping by replacing the La-sites with alkali-earth metals or by overdoping oxygen. However, the present study demonstrates that the HPT processing induces structural strain, and subsequent annealing stabilizes the hyperoxia phase, i.e., the superoxide phase. The superconducting transition temperature Tc systematically varies as a function of the revolution number N in HPT processing under compression of 6 GPa, and Tc has the maximum value of approximately 40 K for N≤1. Stabilized superconducting states intrinsically have a large critical field at the 20 T level. This approach proposes a high-pressure material synthesis method that is useful for mechanically tuning carriers in insulating La2CuO4.
Three-channel terahertz beam steering based on polarization multiplexed metasurfaces
Authors: Li Pengxuan , Fan Fei , Wang Hao , Zhao Dan , Cheng Jierong , Chang Shengjiang
Published: January 2025

Terahertz (THz) beam steering is of great significance for realizing high-speed communication, radar scanning, and information processing, but it is limited by the number of channels and strong crosstalk between different channels. In this work, we demonstrate a three-channel polarization multiplexed metasurface, enabling polarization-dependent and frequency-dependent multi-beam steering. The independent phase gradients are superimposed on a single-layer structure for three non-orthogonal polarization states, and we solved the supercell structure of the metasurface by Least Squares Approximation and Gradient Descent Algorithm to effectively suppress the crosstalk between non-orthogonal modes. The experimental results show that the deflection angles on different linear polarization states and frequencies can cover the angle range of 15°–50° in the broadband range of 0.3–0.5 THz, and the maximum crosstalk between channels is −27.84 dB at the center frequency of 0.4 THz. The proportion of beam energy correctly multiplexed by each channel reaches >80%. This non-orthogonal polarization multiplexing mechanism is of great value for THz metasurface multi-channel wavefront manipulation.
Investigation on the flow characteristics of a centrifugal pump with a fractured leading edge of a single blade
Authors: Li Huairui , Zhang Rongyong , Fu Qiang , Liu Yingqian , Chen Huazheng , Bian Rui , Zhu Rongsheng
Published: January 2025

Centrifugal pumps are essential in various industrial applications, and their stable and efficient operation has a direct impact on the overall performance of the system. This study simulates different lengths of fractures at the LE (leading edge) of a single blade to conduct an in-depth analysis of their effects on internal flow and transient characteristics. The study reveals that the most significant effects of blade LE fractures on pump performance occur near a flow rate of 0.8Qd, where the head and efficiency can decrease by up to 6.19% and 3.77%, respectively, compared to the original blades. Blade fractures lead to deterioration of flow on the pressure and suction sides, creating vortices and inducing leakage flow, while entropy production significantly increases in this area. A 230.1% increase in the distribution angle and a 26.6% increase in the maximum radial force reflect changes in the radial force distribution. Also, LE fractures make the wall pressure pulsations stronger at the SPF (shaft passing frequency), and they make the amplitude of the pulsations on the blade surface much bigger at both SPF and 3SPF frequencies. Finally, LE fractures change the way vibrations behave at radial measurement points in both the x and y directions in a big way. The acceleration amplitudes at SPF and 3SPF frequencies go up by 125.8%, 193.1%, and 62.5%, 184.6%, respectively. These findings provide an important theoretical basis for the early warning and diagnosis of blade fracture failures.
h-CMD: An efficient hybrid fast centroid and quasi-centroid molecular dynamics method for the simulation of vibrational spectra
Authors: Limbu Dil K. , London Nathan , Faruque Md Omar , Momeni Mohammad R.
Published: January 2025

Developing efficient path integral (PI) methods for atomistic simulations of vibrational spectra in heterogeneous condensed phases and interfaces has long been a challenging task. Here, we present the h-CMD method, short for hybrid centroid molecular dynamics, which combines the recently introduced fast quasi-CMD (f-QCMD) method with fast CMD (f-CMD). In this scheme, molecules that are believed to suffer more seriously from the curvature problem of CMD, e.g., water, are treated with f-QCMD, while the rest, e.g., solid surfaces, are treated with f-CMD. To test the accuracy of the newly introduced scheme, the infrared spectra of the interfacial D2O confined in the archetypal ZIF-90 framework are simulated using h-CMD compared to a variety of other PI methods, including thermostatted ring-polymer molecular dynamics (T-RPMD) and partially adiabatic CMD as well as f-CMD and experiment as reference. Comparisons are also made with classical MD, where nuclear quantum effects are neglected entirely. Our detailed comparisons at different temperatures of 250–600 K show that h-CMD produces O–D stretches that are in close agreement with the experiment, correcting the known curvature problem and redshifting of the stretch peaks of CMD. h-CMD also corrects the known issues associated with too artificially dampened and broadened spectra of T-RPMD, which leads to missing the characteristic doublet feature of the interfacial confined water, rendering it unsuitable for these systems. The new h-CMD method broadens the applicability of f-QCMD to heterogeneous condensed phases and interfaces, where defining curvilinear coordinates for the entire system is not feasible.
Flame structure transition and instability excitation by pilot fuel in a centrally staged combustor
Authors: Fu Pengfei , Li Shan , Hou Lingyun , Wen Qi , Li Jie , Ma Hongyu
Published: January 2025

The pilot stage plays a crucial role in central-staged combustion technology. This study aimed to investigate the impact of the jet-type pilot stage on the flame structure and combustion instability in a novel strong coupled centrally staged swirl gas turbine combustor, using both experiments and large eddy simulations (LES). Nonlinear dynamic analyses of dynamic pressure, including phase and recurrence plots, were performed alongside a proper orthogonal decomposition of the dynamic flame structures. It is indicated that a richer pilot stage worsens the instability of the centrally staged combustion system. An increase in the equivalence ratio of the pilot stage leads to enhanced non-premixed combustion and a downstream shift in the heat release region. The transition results in the shift of flame shape from an attached V-shaped flame to an intermittent lifting U-shaped flame. The flame surface statistics from LES results including the strain rate and progress variable gradient of lean and rich pilot conditions were compared. Under richer pilot conditions, the lifting U-shaped flame demonstrates increased sensitivity to flow field fluctuations, intensifying vortex–flame interactions. This interaction causes the large-scale flame surface stretching and even extinction of the pilot stage flame, exacerbating combustion instability observed in this study. These insights offer a deeper understanding of the impact of the jet-type pilot stage on the novel multi-staged central combustion systems.
A novel prediction model of grounding resistance based on long short-term memory
Authors: Pu Xinghai , Zhang Jing , Wang Fei , Xue Shuai
Published: January 2025

This study aims to investigate the use of Long Short-Term Memory (LSTM) models for predicting temporal variations in grounding resistance using time series data. This analysis is the first to apply LSTM models to grounding resistance prediction, utilizing experimental data, including soil resistivity and rainfall. The LSTM model is trained, validated, and tested with various parameters, enabling a comparative assessment of its accuracy in capturing grounding resistance variations. Furthermore, the study benchmarks the LSTM model’s performance against traditional Artificial Neural Networks, confirming the LSTM’s superior predictive accuracy regarding time-dependent changes in grounding resistance. The results of the prediction show that LSTM significantly surpasses traditional methods in terms of mean absolute percentage error, with an improvement of 72.73% across various metrics.
Enhancing the superconducting properties of bulk (Sm,Eu,Gd)Ba2Cu3O7−δ: Impact of BaO2 and Ag2O addition via infiltration growth process in air
Authors: Agarwal Akash Garg , Muralidhar Miryala
Published: January 2025

The air fabrication of bulk LREBa2Cu3O7−δ [where LRE can be Nd, Sm, Eu, Gd, or combinations such as (Y,Gd), (Y,Er), (Sm,Eu,Gd), (Nd,Eu,Gd), and (Nd,Sm,Gd)] holds the potential to revolutionize the cost-effective production of high-temperature superconductors. This method enables batch processing on an industrial scale, opening up a range of applications across various fields with enhanced superconducting performance. In this study, we fabricated large single-domain (Sm,Eu,Gd)Ba2Cu3O7−δ using the top-seeded infiltration growth process in air. To suppress the RE/Ba substitutions, BaO2 was added in the secondary (Sm,Eu,Gd)2BaCuO5 (SEG-211) phase with various BaO2 weight percentages. The optimized sample achieved an onset critical temperature Tc(onset) of 94.57 K and a transition width of ΔTc < 1 K, representing a 71% improvement in ΔTc over the reference sample. Furthermore, the self-field critical current density Jc of the BaO2-optimized sample was 33.55 kA/cm2 at 77 K and 62.26 kA/cm2 at 65 K, H//c-axis. The addition of Ag2O to the BaO2-optimized sample yielded an onset critical temperature of Tc(onset) > 93 K and a transition width of ΔTc < 1.5 K. Significant improvement in high-field critical current density was observed in the Ag2O-added sample, with a Jc value of 18.14 kA/cm2 at 77 K and 1 T, and 50.54 kA/cm2 at 65 K and 3 T, H//c-axis. These results indicate that ternary (Sm,Eu,Gd)Ba2Cu3O7−δ can be produced in air using the IG process with optimal BaO2 and Ag2O, which is crucial for batch production in air.
Soil carbon, organic matter fractions, and soil physical quality under different sugarcane harvesting systems in north-east Brazil
Authors: Lima Handerson Brandão Melo de , Borges Sávio Tavares Ferreira , Santos Crislâny Canuto dos , Maia Stoécio Malta Ferreira
Published: January 2025

Context Sugarcane cultivation is one of the main agricultural activities in Brazil. Among the production systems, unburnt harvesting has gained prominence and has been replacing the burning system. The use of unburnt harvesting system increases straw retention on soil surface, which influences the quantity and quality of soil organic matter (SOM). Aims We evaluated the effects of burnt and unburnt sugarcane harvesting systems on soil organic carbon (SOC) stocks and SOM dynamics in the north-east region of Brazil. Methods The study was conducted at three sites, each containing one area of burnt sugarcane harvesting system (Bs), two areas of unburnt sugarcane harvesting systems (Us) and one area of native vegetation (NV), totaling 12 collection sites. Key results The results show that the conversion of NV to sugarcane cultivation areas led to SOC loss, which ranged from 7% to 62%, and reduced soil quality due to losses of particulate organic matter (POM) and increased soil bulk density (BD), being corroborated by changes in other indicators, such as soil degree of compactness (SDC), and reduction in the soil structural stability index (SSI). Conclusions Despite the losses when compared to NV, the Us system showed increments in SOC, POM-C, and SSI and reductions in BD and SDC compared to Bs. Implications The findings of this study highlight the importance of understanding the impact of land use change on the properties of SOM.
Endonuclease G promotes hepatic mitochondrial respiration by selectively increasing mitochondrial tRNA
Thr
production
Authors: Xu Xihui , Penjweini Rozhin , Székvölgyi Lóránt , Karányi Zsolt , Heckel Anne-Marie , Gurusamy Devikala , Varga Dóra , Yang Shutong , Brown Alexandra L. , Cui Wenqi , Park Jinsung , Nagy Dénes , Podszun Maren C. , Yang Sarah , Singh Komudi , Ashcroft Stephen P. , Kim Jeonghan , Kim Myung K. , Tarassov Ivan , Zhu Jun , Philp Andrew , Rotman Yaron , Knutson Jay R. , Entelis Nina , Chung Jay H.
Published: January 2025

Mitochondrial endonuclease G (EndoG) contributes to chromosomal degradation when it is released from mitochondria during apoptosis. It is presumed to also have a mitochondrial function because EndoG deficiency causes mitochondrial dysfunction. However, the mechanism by which EndoG regulates mitochondrial function is not known. Fat accumulation in metabolic dysfunction–associated steatotic liver disease (MASLD), which is more common in men, is caused in part by mitochondrial dysfunction. EndoG expression is reduced in MASLD liver, and EndoG deficiency causes MASLD in an obesity-independent manner but only in males. EndoG promotes mitochondrial respiration by resolving mitochondrial tRNA/DNA hybrids formed during mtDNA transcription by recruiting RNA helicase DHX30 to unwind them. EndoG also cleaves off the 3′-end of the H-strand transcript that can prevent mt-tRNA
Thr
precursor cloverleaf-folding, and processing, which increases mt-tRNA
Thr
production and mitochondrial translation. Using fluorescent lifetime imaging microscopy technology to visualize oxygen consumption at the individual mitochondrion level, we found that EndoG deficiency leads to the selective loss of a mitochondrial subpopulation with high-oxygen consumption. This defect was reversed with mt-tRNA
Thr
supplementation. Thus, EndoG promotes mitochondrial respiration by selectively regulating the production of mt-tRNA
Thr
in male mice.
A mutant ASXL1-BAP1-EHMT complex contributes to heterochromatin dysfunction in clonal hematopoiesis and chronic monomyelocytic leukemia
Authors: Dong Zhen , Sepulveda Hugo , Arteaga-Vazquez Leo J. , Blouin Chad , Fernandez Jenna , Binder Moritz , Chou Wen-Chien , Tien Hwei-Fang , Patnaik Mrinal M. , Faulkner Geoffrey J. , Myers Samuel A. , Rao Anjana
Published: January 2025

ASXL transcriptional regulator 1 (ASXL1)
is one of the three most frequently mutated genes in age-related clonal hematopoiesis (CH), alongside
DNA methyltransferase 3 alpha (DNMT3A)
and
Tet methylcytosine dioxygenase 2
(
TET2)
. CH can progress to myeloid malignancies including chronic monomyelocytic leukemia (CMML) and is also strongly associated with inflammatory cardiovascular disease and all-cause mortality in humans. DNMT3A and TET2 regulate DNA methylation and demethylation pathways, respectively, and loss-of-function mutations in these genes reduce DNA methylation in heterochromatin, allowing derepression of silenced elements in heterochromatin. In contrast, the mechanisms that connect mutant ASXL1 and CH are not yet fully understood. CH/CMML-associated
ASXL1
mutations encode C-terminally truncated proteins that enhance the deubiquitinase activity of the ASXL-BAP1 “PR-DUB” deubiquitinase complex, which removes monoubiquitin from H2AK119Ub. Here, we show that ASXL1 mutant proteins interact with the euchromatic histone lysine methyltransferases 1 and 2 (EHMT1–EHMT2) complex, which generates H3K9me1 and me2, the latter a repressive modification in constitutive heterochromatin. Compared to cells from age-matched wild-type mice, we found that expanded myeloid cells from old (≥18-mo-old)
Asxl1tm/+
mice, a heterozygous knock-in mouse model of CH, display genome-wide decreases of H3K9me2, H3K9me3, and H2AK119Ub as well as an associated increase in expression of transposable elements (TEs) and satellite repeats. Increased TE expression was also observed in monocytes from
ASXL1
-mutant CMML patients compared to monocytes from healthy controls. Our data suggest that mutant ASXL1 proteins compromise the integrity of both constitutive and facultative heterochromatin in an age-dependent manner by reducing the levels of H3K9me2/3 and H2AK119Ub. This increase in TE expression correlated with increased expression of nearby genes, including many interferon-inducible (inflammation-associated) genes (ISGs).