bluuebunny/crossref_metadata_2025 huggingface dataset:
Random P-bifurcation in a Duffing–van der Pol vibro-impact system with a Bingham model
Authors: Kan Zijian , Wang Jun , Zhang Jianchao , Niu Jiangchuan
Published: February 2025

The present work investigates stochastic P-bifurcation phenomena in a Duffing–van der Pol vibro-impact oscillator containing a Bingham model under Gaussian white noise excitation. By employing non-smooth transformations and stochastic averaging techniques, an approximate analytical method is proposed to analyze the stochastic response and bifurcation behavior of nonlinear systems with friction and vibro-impact effects. Using a non-smooth transformation, the stochastically excited vibro-impact oscillator is converted into an approximately equivalent system without velocity discontinuities. Subsequently, the friction term is handled, and stochastic averaging is applied to derive the averaged stochastic Itô equation. The corresponding Fokker–Planck–Kolmogorov equation is then solved to obtain the probability density function of the system's steady-state response. Numerical simulations are conducted to verify the reliability of the proposed method. Based on these results, the critical parameter conditions for stochastic P-bifurcation are derived using singularity theory, considering both the amplitude probability density and the joint probability density of system displacement and velocity. Bifurcation diagrams, extreme value plots, amplitude probability density plots, velocity probability density plots, and joint probability density plots of system displacement and velocity are constructed for different parameter spaces. The findings demonstrate that changes in the viscous damping coefficient of the magnetorheological damper, Coulomb damping force, noise intensity, vibro-impact coefficient, and nonlinear damping coefficient can all induce stochastic P-bifurcations.
Multiscale Res2RAFT particle image velocimetry algorithm optimized with global attention mechanism
Authors: Wen Jingqi , Zhou Zhiyu , Yang Junyi
Published: February 2025

Particle Image Velocimetry (PIV) technology is widely used in experimental fluid mechanics. However, due to the complexity of underwater environments, traditional PIV methods face significant challenges in terms of measurement accuracy and adaptability. With the advancement of computer vision and deep learning technologies, an increasing number of optical flow networks have been applied to PIV tasks, yet their performance in fine-grained displacement field prediction remains limited. To address this issue, this paper proposes a new optical flow network improvement model, Res2RAFT. By introducing the Bottle2neck module from the Res2Net network, we constructed the Res2BasicEncoder to enhance multiscale feature extraction capabilities. Additionally, a Global Attention Module was incorporated into the model to improve the prediction accuracy of complex flow fields by enhancing global dimension interaction features. Experimental results show that Res2RAFT achieves average endpoint errors of 2.0758, 8.0548, and 11.7254 on the Cylinder, Direct Numerical Simulation turbulence, and Surface Quasi-Geostrophic categories, respectively, representing improvements of 17.4%, 30.3%, and 27.3% compared to the RAFT-PIV model. Overall, the model achieved an accuracy improvement exceeding 20% in complex flow fields, providing new possibilities for the application of PIV technology in more complex fluid scenarios.
Suppression of vortex-induced vibration of a circular cylinder using a pair of jets near the free surface
Authors: Zhang Baoshou , Yang Zihan , Lv Jingze , Li Boyang , Li Zijian , Zhao Xizhi , Li Huichao , Zhang Rui
Published: February 2025

In practical engineering applications, Vortex-Induced Vibration (VIV) poses significant hazards to objects. Objects located near the free surface, such as those on a water platform, will also be affected by VIV. Therefore, the suppression of cylindrical vibration near the free surface should be paid more attention. In this paper, the effect of a pair of jets on cylinder vibration suppression near free surface is studied on the basis of two-dimensional model. To investigate the suppression effect of jet flows on the vibration of cylinders at different submerged depths near the free surface, four different submerged depth ratios (H* = 1, 2, 3, and 10) were studied, and a group of bare cylinders with submerged depth ratio H* = 2 was used for comparative analysis. The control effect of a couple of the jets on the cylinder increases as the submergence depth ratio decreases in the upper branch and lower branch. The motion response has changed from VIV to galloping in the lower branch. The flow is influenced by the narrow gap between the controlled cylinder and the free surface when it is close to the free surface, and a high-pressure area will be generated above the cylinder to suppress the vibration. Simultaneously, the presence of the jet disrupts the vortices forming on the rear side of the cylinder, thereby achieving the purpose of suppressing cylinder vibration. Furthermore, near the free surface, the presence of the jet alters the vortex structure, which also contributes to suppressing cylinder vibration.
Acoustic levitation of super-wavelength elastic films using ultrasound phased arrays
Authors: Arakawa Gakuto , Suzuki Shun , Kamigaki Takaaki , Makino Yasutoshi , Shinoda Hiroyuki
Published: February 2025

We present a method for levitating films with a surface size larger than the wavelength using airborne ultrasound phased arrays. A typical example is a polyimide film with a side length of 40–50 mm and a thickness of 5 μm (aspect ratio: 8–10 × 103). We verified our method by measuring the height, horizontal position, and vibration of the levitating film. The results show that the film levitates at the height of the original standing wave node and at discrete horizontal positions approximately every transducer interval. The levitated film vibrates at the same frequency as the ultrasonic transducer and cannot be regarded as rigid against ultrasonic waves. Different film materials and thicknesses were examined, including metal foils and wood papers. In this study, the maximum surface density of the films that levitated was 3.5 ×10−2 mg/mm2. Therefore, the proposed method can be used to hold film samples in the air for observation or as an aerial screen.
Buried Au nanoparticles-assisted enhancement of local electric field toward improved resistance switching in Au/ZnO/Si structures
Authors: Lv Zhicheng , Chen Mingming , Zhang Qunzhong , Zhang Huimin , Zhang Chenglin , Cao Dawei
Published: February 2025

In this work, we reported the fabrication of improved Au/ZnO/Si resistance switching (RS) devices achieved by introducing buried cone-like Au nanoparticles (NPs). The Au NPs were facilely obtained by thermally annealing a thin Au film grown on a Si substrate, which did not influence the subsequent growth of ZnO thin films. Electric measurements verified typical RS behaviors in the Au/ZnO/Si devices, which are related to the recovery and rupture of conductive filaments due to electric field-driven oxygen vacancy migration. Notably, COMSOL-based electrostatic field simulations on Au/ZnO/Au structures have shown that an enhanced local electric field with 4.5 times enhancement was produced at the tip of Au NPs, which facilitated the oxygen vacancies migration around the tip of Au NPs. Accordingly, controlled formation and rupture of conductive filaments are proposed in the Au/ZnO/Au NPs/Si devices, which greatly improved the RS window, stability, and endurance. The results shown in this work may pave the way for the fabrication of high-performance oxide-based RS devices in the future.
Axisymmetric background-oriented schlieren measurement for cylindrical combustion flow in micro-rocket torches
Authors: Hirayama Y. , Ogawa S.
Published: February 2025

A high-precision background-oriented schlieren (BOS) measurement technique was developed to analyze the density field of gases ejected from a micro-rocket torch in scramjet combustors. The BOS method was enhanced using an axisymmetric model and inverse Abel transforms, thereby allowing accurate density measurements in complex flow fields and addressing the limitations of traditional BOS applications. Validation tests confirmed the accuracy and stability of the BOS analysis, demonstrating its robustness against experimental noise and reliable density reconstruction. Experiments with varying equivalence ratios revealed significant effects on the ejected gas-density distribution and spread. Under fuel-rich conditions, the combustion temperature and molecular interactions increase, resulting in a lower density and greater jet expansion. This effect produced a clear boundary between the ejected gas and the surrounding atmosphere, whereas lean combustion conditions displayed more diffuse gas boundaries and instability, owing to the lower hydrogen concentration and combustion temperature. These observed behaviors were linked to Lewis number effects, where higher values under fuel-rich conditions enhanced combustion stability and maintained a more defined gas boundary. To further improve the accuracy of the density analysis, this study applied a modified Gladstone–Dale constant based on the in-flame gas composition. The BOS approach was optimized for angled fields of view and extended measurement areas. The results demonstrated that the BOS technique, particularly with the integration of axisymmetric modeling, provides an effective approach for capturing intricate flow structures in combustion, including spatial density gradients along both radial and axial directions.
High-temperature annealing induced electrical compensation in UID and Sn doped β-Ga2O3 bulk samples: The role of VGa–Sn complexes
Authors: von Bardeleben H. J. , Zhou Xuanze , Zhou Jingbo , Xu Guangwei , Long Shibing , Gerstmann U.
Published: February 2025

By electron paramagnetic resonance (EPR) and photoluminescence spectroscopy, we have investigated the effect of high-temperature annealing under oxygen atmosphere on the electrical and defect properties of unintentionally doped (UID) and highly doped (Sn) n-type bulk samples of β-Ga2O3. The EPR analysis of the shallow donor concentration shows efficient electrical compensation in the Sn doped β-Ga2O3 samples but only marginal changes for the UID samples. In the Sn doped samples, we observe the formation of a Ga vacancy related acceptor defect responsible for the compensation. Its spin Hamiltonian parameters are electron spin S = 1/2, g-tensor g11 = 2.0423, g22 = 2.0160, g33 = 2.0024, and hyperfine interaction (hf) with two equivalent Ga atoms with A(69Ga) = 28 G. To identify its microscopic structure, we have performed first-principles calculations of the EPR parameters and the associated photoluminescence spectra of different Ga vacancy–Sn donor complexes, including a simple nearest neighbor pair VGa–SnGa. From these calculations, we attribute this VGa defect to a negatively charged split vacancy complex VGa1–Snib–VGa1. This VGa defect is different from the irradiation induced VGa center.
Resistance experiments on ships in a leader-follower formation
Authors: Zhu Fengshen , Dai Saishuai , Yuan Zhi-Ming
Published: February 2025

The interaction between two ships in a leader-follower formation involves interference by both waves and viscosity, making the phenomenon highly complex. A series of experiments are conducted in this study to measure the total resistance of ships moving individually and in two-ship formations on calm water. The results indicate that the shape of the bow has a more significant impact on the total resistance of single ships than the shape of the stern. Specifically, the total resistance of a single ship with a transom stern is nearly identical to that of a ship with a sharp stern. However, ships with a flat bow exhibit significantly higher total resistance compared to those with a sharp bow. In a two-ship single-file formation, the hydrostatic drag of both the leading and trailing ships is significantly reduced when the gap between the two ships is small. This reduction occurs because the hollow in the water aft the transom stern induced by flow separation is filled by the bow waves of the trailing ship. When the trailing ship is positioned in the divergent wave zone within the wake of the leading ship, wave interference between the two ships becomes the dominant factor influencing the variation in the total resistance of the trailing ship. As the gap between the two ships increases further, the wave interference weakens; however, the trailing ship still experiences a substantial reduction in resistance due to weakened flow separation and bubble drag reduction within the turbulent–bubble mixed flow region.
Dynamics and modulation of cosmic ray modified magnetosonic waves in a galactic gaseous rotating plasma
Authors: Turi Jyoti , Banerjee Gadadhar
Published: February 2025

The influence of the presence of cosmic fluid on the magnetosonic waves and modulation instabilities in the interstellar medium (ISM) of spiral galaxies is investigated. The fluid model is developed by modifying the pressure equation in such dissipative rotating magnetoplasmas incorporating thermal ionized gas and cosmic rays. Applying the normal mode analysis, a modified dispersion relation is derived to study linear magnetosonic wave modes and their instabilities. The cosmic rays influence the wave damping by accelerating the damping rate. The standard reductive perturbation method is employed in the fluid model leading to a Korteweg–de Vries–Burgers (KdVB) equation in the small-amplitude limit. Several nonlinear wave shapes are assessed by solving the KdVB equation, analytically and numerically. The cosmic ray diffusivity and magnetic resistivity are responsible for the generation of shock waves. The modulational instability (MI) and the rogue wave solutions of the magnetosonic waves are studied by deriving a nonlinear Schrödinger equation from the obtained KdVB equation under the assumption that the cosmic ray diffusion and magnetic resistivity are weak and the carrier wave frequency is considerably lower than the wave frequency. The influence of various plasma parameters on the growth rate of MI is examined. The modification of the pressure term due to cosmic fluid reduces the MI growth in the interstellar medium. In addition, a quantitative analysis of the characteristics of rogue wave solutions is presented. Our investigation's applicability to the interstellar medium of spiral galaxies is traced out.
Confinement and wettability-driven dispersed phase hydrodynamics in cross-flow jets at low velocity and density ratios
Authors: Mondal Nilanjan , Biswas Diptesh , Mukherjee Rabibrata , Bakli Chirodeep
Published: February 2025

The evolution characteristics of a low-velocity dispersed phase into continuous shear flow have numerous applications across biomedical devices, chemical processes, water management in fuel cells, spray systems, film deposition, and atomizing devices. The flow characteristics arise from a complex interplay of wettability, hydrodynamics, and interfacial properties, which, when constrained by confined geometries such as those in fuel cells, present a fascinating multiphase-multiphysics problem. This study investigates the impact of the chemical signature of a confined geometry and the velocity ratio between the dispersed and continuous phases on the evolution of the dispersed phase. The footprint and shape of the generated droplet guide the pressure distribution, deformation, and subsequent cross-flow-induced stretching. By systematically analyzing the dynamic effects of capillarity, inertia, air-shear, gravity, viscosity, wettability, and confinement, we classify the fate of a liquid droplet within classical flow regimes: jetting, threading, and dripping. These distinct flow regimes are mapped using classical non-dimensional numbers, and a quasi-universal characteristic is obtained relative to velocity ratios. The findings of this research contribute to precise control and prediction of dispersed-phase hydrodynamics, which play a pivotal role in enhancing the efficiency of fuel cells, droplet generation devices, water harvesting systems, film deposition techniques, coatings, and point-of-care diagnostic devices. The work underscores the relevance of integrating experimental and computational insights for optimizing interface-driven processes in interdisciplinary applications.
Regulation of intermolecular interaction energies for improving polarization-sensitive photodetection
Authors: Shao Zhimin , Yu Feng , Fan Yijing , Tan Zhi , Lin Guanglu , Luo Junquan , Chen Chuan , Lv Yibo , Chen Peng , Mai Wenjie , Su Wenyan , Fan Qunping , Zhang Wei , Jiang Jiaxing , Yang Renqiang , Hou Lintao
Published: February 2025

In this study, we systematically modified the polymer structure by incorporating non-conjugated units and substituting atoms in the fused-ring core, resulting in significant alterations to intermolecular interaction energies of −974.1, −1076.4, and −1115.1 kJ/mol between the polymer:chloroform and polymer:ethylene glycol. These modifications greatly enhance the orientation of the all-polymer backbone and the intrinsic polarization-sensitive performance of the device, demonstrating exceptional capabilities in polarized light detection and imaging. The optimal device exhibits an ultra-fast response speed of 10.6 μs, a wide frequency response of 17.78 kHz, and a large linear dynamic range of 132.3 dB with good imaging ability, indicating potential benefits for a diverse array of extreme applications. This work illustrates how the strategy of incorporating non-conjugated units and modifying the core atoms can contribute to continuous improvements in molecular orientation and polarized light detection.
Effect of interface structure on solid-state amorphization of dual-phase Mg alloys
Authors: Li X. Y. , Song H. Y. , Bo H. Y.
Published: February 2025

The interface and its structure have a significant impact on the mechanical properties of the magnesium (Mg) alloys. However, the role of the interface in the solid-state amorphization process of the Mg alloys is still unclear. Here, the effect of four interface structures, namely, basal/prismatic (BP), stacking fault (SF), twin boundary (TB), and high-angle grain boundary (HAGB) on the solid-state amorphization (SSA) of the amorphous/crystalline dual-phase Mg alloys is investigated using molecular dynamics simulation. The results indicate that the introduction of all four interfaces increases the SSA degree of the alloys. For the four models, the SSA degree of the alloys varies from high to low in order as the BP model, the TB model, the SF model, and the HAGB model, which means that atomic diffusion has a significant dependence on the interface structure and interface energy. The results show that the interface plays two roles in the SSA process: first, it changes the structure of the amorphous–crystalline interface in contact with the interface and second, the interface with a more open structure itself is a fast channel for atomic diffusion, both of which are beneficial for the SSA of the alloys.
Terahertz non-Hermitian topological metasurface with switchable characteristics of transmission and reflection
Authors: Zhang Yuping , Liu Yang , Wang Yu , Zheng Siyu , Hao Xiaoyu , Liu Meng , Zhang Huiyun
Published: February 2025

With the increasing exploration of non-Hermitian systems, the topological properties of exceptional points (EPs) in non-Hermitian metasurfaces have garnered significant attention. This paper investigates a VO2-based non-Hermitian topological metasurface within the terahertz (THz) frequency domain. We achieve switching between transmission and reflection by actively controlling the conductivity of vanadium dioxide (VO2), thereby realizing dual-channel EPs simultaneously. Notably, there is a consistent 2π phase accumulation around the EPs, irrespective of the closure path. Furthermore, we demonstrate that EP can also be observed by varying the incidence angle. The examination of dual-channel EPs and their topological properties offers a promising avenue for the development of topological devices and future applications in optical transmission and modulation.
Rheology of mRNA-loaded lipid nanodumbbells
Authors: Kanso Mona A. , Singh Shalini , Giacomin Alan J. , Braatz Richard D.
Published: February 2025

In one important chemical engineering unit operation of messenger ribonucleic acid (mRNA) vaccine manufacture, the precious mRNA payload is encapsulated in lipid nanoparticles (LNPs). Recent elegant cryogenic-transmission electron microscopy [Brader et al., Biophys. J. 120, 2766 (2021)] reveals that these lipid nanoparticles take the form of dumbbell suspensions. When encapsulating their mRNA payloads, these dumbbells can be both lopsided and interpenetrating, with the smaller of the two beads carrying the payload. In this work, we arrive at analytical expressions for these suspensions of lopsided lipid nanoparticle dumbbells encapsulating mRNA payloads. For this, we first exploit rigid dumbbell theory [Abdel-Khalik and Bird, Appl. Sci. Res. 30, 268 (1975)], which relies on the orientation distributions of the lopsided dumbbells, to predict the suspension rheology, and specifically to predict how this departs from Newtonian behavior. We next exploit elastic dumbbell theory [Phan-Thien et al., Phys. Fluids 36, 071707 (2024)], which also relies on the orientation distributions of the lopsided dumbbells and to which we add dumbbell stretching. Our results include analytical expressions for the relaxation time, rotational diffusivity, zero-shear viscosity, shear stress relaxation function, steady-shear viscosity and both the viscous part and minus the elastic part of the complex viscosity. We determine the rotational diffusivity of the mRNA-loaded lipid nanoparticle nanodumbbells from small-amplitude oscillatory shear measurements.
Comparison between the acoustic fields of conventional and tubercled propellers
Authors: Posa Antonio , Broglia Riccardo , Shi Weichao , Felli Mario
Published: February 2025

The results of large eddy simulations on a cylindrical grid consisting of 5.8 × 109 points are utilized to reconstruct the acoustic fields radiated by conventional and tubercled propellers in wetted conditions, using the Ffowcs Williams and Hawkings acoustic analogy. The analysis of the flow features demonstrates that while the distribution of the turbulent fluctuations of pressure on the surface of the propeller blades is substantially affected by the presence of leading edge tubercles (LETs), this is not the case for the wake flow, which does not display dramatic differences across cases. As a result, while the loading component of the acoustic field, which is the leading one at most frequencies, is significantly modified by the implementation of LETs, this is not the case for the quadrupole component, which is rather similar between conventional and tubercled geometries. The loading sound of the tubercled propellers is reduced around the blade frequency, fb, while it is reinforced at higher frequencies, around 10fb. Furthermore, while the loading sound was found usually the leading one, at the highest resolved frequencies, above 20fb, the quadrupole sound was verified more intense than the linear one, even in the acoustic far field, for both conventional and tubercled propellers.
Experimental study of the hydraulic and aeration characteristics within the vortex drop shaft spillway
Authors: Zhang Bin , Fu Xiaoli , Hu Xianrui , Luo Bingcheng , Fu Hui , Guo Xinlei
Published: February 2025

This study focuses on a novel type of vortex drop shaft spillway, addressing the lack of comprehensive research on its hydraulic and aeration characteristics. A combination of experimental and theoretical methods was employed to investigate these characteristics in detail. The results reveal that the relationship between the swirl angle and the Froude number (Frx) remains unclear. However, a positive correlation was observed between the water layer thickness, flow velocity, and Frx. Analytical formulas derived for the swirl angle and water layer thickness showed a small relative deviation from experimental data, and the maximum relative differences are about 4% and 8%, respectively. Furthermore, a linear negative correlation was identified between vortex cavity length, relative aeration rate (β), and Frx. An empirical relationship between β and Frx was established. When Frx ranges from 0.064 to 0.89, the aeration concentration along the shaft gradually decreases, while it increases along the outlet tunnel. At lower Frx values, the transverse aeration concentration in the upper layer of the outlet tunnel is highest at the center and lower at the sides. In the lower layer, the concentration is higher at the sides and lower at the center. The aeration concentration near the wall of the outlet tunnel is more than 4%, which can effectively reduce the cavitation damage in the outlet tunnel. These findings deepen the understanding of the hydraulics and aeration mechanism in the vortex drop shaft spillway, offering theoretical support for its application and further development.
Multiphysics coupling particle dissolution in aluminum electrolysis cells based on computational fluid dynamics and discrete element model
Authors: Hou Wenyuan , Hu Xia , Zhang Chunhua , Liu Lei , Liu Hantao , Liu Wei , Li Mao , Li Hesong
Published: February 2025

Particle dissolution is a common phenomenon in the metallurgical and chemical industries, involving heat and mass transfer. A user-defined solver toward the computational fluid dynamics and discrete element model method with particle dissolution sub-models integrating was developed based on the open-source software OpenFOAM-LIGGGHTS, which can simulate the alumina and spent refractory material (SRM) dissolution in electrolysis cells. This approach solves the fluid phase in the Eulerian framework and the particle motion in the Lagrangian framework, comprehensively considering the particle size shrinkage, bath temperature response, and concentration diffusion during particle dissolution. The model's accuracy was verified against experimental results. The dissolution of the alumina and SRM mixture at different mixing ratios was simulated. The results show that as the proportion of SRM in the mixture increases, the mixture's dissolution rate decreases, and the remaining undissolved mass increases significantly. The SRM content in the mixture will not affect the operation stability of aluminum electrolysis cells when it is 10%, and the maximum content cannot exceed 30%. The mixture particles and the dissolved alumina and silica first move around along the inter-anode gap and center channel and then gradually transport and diffuse to the anode–cathode distance region to replenish the consumed alumina and silica. The established model and method could provide guidance for optimizing the process parameters and feeding strategies of the electrolysis cell, further improving the dissolution rate of the mixtures and increasing the SRM consumption.
Experimental study on multi-scale characterization and damage model of coal particle pores under circulating critical outburst pressure
Authors: Liu Xuan , Fu Xiang , Wu Qixuan , Chang Teng , Wang Yifan
Published: February 2025

In the process of coal seam mining, continuous high pressure gas circulation causes accumulating microscopic damage in coal, leading to a decrease in fracture toughness. When pore damage reaches a critical level, the coal body may fracture and become unstable under high pressure gas. Understanding this damage is essential for uncovering the mechanisms of coal and gas outbursts. This study presents experiments on circulating critical outburst pressure desorption using a high pressure desorption device, combined with low temperature liquid nitrogen adsorption tests, to analyze the pore parameters of different coal samples. The experimental results indicate that as the number of high pressure cycles increases, methane desorption generally increases. Bituminous coal exhibits the highest desorption, while lignite shows the lowest. Circulating high pressure significantly impacts the pore characteristics of coal samples. The pores in bituminous coal are well developed, with a liquid nitrogen adsorption growth rate of 50.01%, compared to only 16.49% for anthracite. The growth rate of micropore volume and specific surface area is the highest, indicating that these are the primary sites for gas storage. A comprehensive analysis of the circulating high pressure gas action, gas desorption characteristics, and pore evolution of coal particles led to the development of a quantitative model for pore damage. This model reveals the extent of damage in different coal types after circulating high pressure desorption, providing a theoretical basis for the migration characteristics of coalbed methane.
Dynamic response characteristics of floating offshore photovoltaic systems with anchor position deviations under extreme environmental conditions
Authors: Du Jun-Feng , Zhang De-Qing , Jin Tao , Zhu Feng-Shen , Yuan Zhi-Ming , Incecik Atilla
Published: February 2025

Floating offshore photovoltaic (FOPV) systems are key technologies for harnessing offshore solar resources, playing a crucial role in mitigating global climate change. Anchoring systems, essential components of FOPV systems, ensure operational safety by limiting floating body's displacement. However, factors such as positioning errors, uneven seabed, and inhomogeneous loads make it challenging to install anchors exactly at their designed locations. These deviations can significantly alter the system's dynamic responses, particularly under extreme environmental conditions, posing potential safety risks. This study aims to explore the dynamic response characteristics of FOPV systems with varying anchor position deviations under extreme sea states, offering valuable insights for system design. First, a coupled numerical model is developed to capture interactions between multiple modules and their mooring lines. Then, the effects of anchor offset distance, direction, relative position, and the incident direction of sea loads on modules motion and mooring tension are discussed. The results indicate that anchor deviations along the mooring projection direction significantly affect the maximum horizontal motion, maximum mooring tension, and minimum mooring safety coefficient, while the maximum heave motion remains largely unaffected. Additionally, when the displaced anchor and the direction of environmental loads acting on the FOPV system are on the same side, the system's maximum dynamic responses are significantly higher compared to those due to the displaced anchor on the leeward side.
AI-empowered digital design of zeolites: Progress, challenges, and perspectives
Authors: Wu Mengfan , Zhang Shiyi , Ren Jie
Published: February 2025

The rise of artificial intelligence (AI) as a powerful research tool in materials science has been extensively acknowledged. Particularly, exploring zeolites with target properties is of vital significance for industrial applications, integrating AI technologies into zeolite design undoubtedly brings immense promise for the advancements in this field. Here, we provide a comprehensive review in the AI-empowered digital design of zeolites. It showcases the state-of-the-art progress in predicting zeolite-related properties, employing machine learning potentials for zeolite simulations, using generative models for the inverse design, and aiding the experimental synthesis of zeolites. The challenges and perspectives are also discussed, emphasizing the new opportunities at the intersection of AI technologies and zeolites. This review is expected to offer crucial guidance for advancing innovations in materials science through AI in the future.
Abscisic acid signaling gates salt-induced responses of plant roots
Authors: Lamers Jasper , Zhang Yanxia , van Zelm Eva , Leong Cheuk Ka , Meyer A. Jessica , de Zeeuw Thijs , Verstappen Francel , Veen Mark , Deolu-Ajayi Ayodeji O. , Gommers Charlotte M. M. , Testerink Christa
Published: February 2025

Soil salinity presents a dual challenge for plants, involving both osmotic and ionic stress. In response, plants deploy distinct yet interconnected mechanisms to cope with these facets of salinity stress. In this investigation, we observed a substantial overlap in the salt (NaCl)-induced transcriptional responses of
Arabidopsis
roots with those triggered by osmotic stress or the plant stress hormone abscisic acid (ABA), as anticipated. Notably, a specific cluster of genes responded uniquely to sodium (Na
+
) ions and are not regulated by the known monovalent cation sensing mechanism
MOCA1
. Surprisingly, expression of sodium-induced genes exhibited a negative correlation with the ABA response and preceded the activation of genes induced by the osmotic stress component of salt. Elevated exogenous ABA levels resulted in the complete abolition of sodium-induced responses. Consistently, the ABA insensitive
snrk2.2/2.3
double mutant displayed prolonged sodium-induced gene expression, coupled with increased root cell damage and root swelling under high salinity conditions. Moreover, ABA biosynthesis and signaling mutants were unable to redirect root growth to avoid high sodium concentrations and had increased sodium accumulation in the shoot. In summary, our findings unveil an unexpected and pivotal role for ABA signaling in mitigating cellular damage induced by salinity stress and modulating sodium-induced responses in plant roots.
Free-electron resonance transition radiation via Brewster randomness
Authors: Gong Zheng , Chen Ruoxi , Wang Zun , Xi Xiangfeng , Yang Yi , Zhang Baile , Chen Hongsheng , Kaminer Ido , Lin Xiao
Published: February 2025

Free-electron radiation, such as Cherenkov radiation and transition radiation, can generate light at arbitrary frequencies and is fundamental to diverse applications, ranging from electron microscopy, spectroscopy, lasers, to particle detectors. Generally, the features of free-electron radiation are stochastic when electrons interact with random media. Counterintuitively, here, we reveal a type of free-electron radiation that has both its intensity and directionality invariant to specific sorts of long-range structural randomness. Essentially, this invariance is enabled by the Brewster effect and the judiciously engineered phase coherence condition of emitted light, namely that the light induced by electron’s penetration through a layered aperiodic nanostructure is engineered to interfere constructively at the Brewster angle. As such, when each constituent layer with a random thickness fulfills this phase coherence condition, there is always the emergence of free-electron resonance transition radiation at the Brewster angle. At this resonant Brewster angle, we further find that the radiation intensity and directionality could be enhanced by orders of magnitude by readily increasing the interface number. The revealed resonance transition radiation via long-range Brewster randomness may offer a feasible route to explore more enticing photonic applications driven by free electrons, such as light sources at previously unreachable spectral regimes, optical frequency combs, particle detectors, and random lasers.
Nanoparticle-Assisted Phonon Transport Modulation in Si/Ge Heterostructures Using Neuroevolution Potential Machine Learning Models
Authors: Yue Jincheng , Chen Rongkun , Ma Dengke , Hu Shiqian
Published: February 2025

Reducing thermal boundary resistance (TBR) is critical for enhancing thermal management efficiency and optimizing the performance of electronic and thermoelectric devices. In this study, we employed non-equilibrium molecular dynamics (NEMD) simulations using Neuroevolution Potential (NEP) machine learning models to investigate how embedding nanoparticles in Si/Ge heterostructures impacts TBR. Our results show a significant reduction in TBR, attributed to enhanced phonon density of states matching via resonance, promoting more efficient elastic phonon transport across the interface. However, this approach also leads to a substantial increase in bulk thermal resistance, highlighting a trade-off where overall heat dissipation is compromised. To address this, we propose an alternative strategy of positioning a nanoparticle directly at the interface to modulate interfacial modes, improving phonon transport efficiency without adversely affecting bulk thermal properties. NEMD simulations validate this approach, showing comparable TBR reduction while mitigating the bulk thermal resistance increase observed with the resonance-based embedding method. This study offers valuable insights into resolving interfacial heat dissipation challenges, providing a balanced strategy for optimizing thermal transport efficiency in nanoscale material systems.
Theoretical analysis and simulation verification for measuring the geometric distances between the silicon spheres with the laser interferometer in G measurement
Authors: Huang Tong , Liu Rui-Qi , Li Rui-Jie , Yang Ling-Ling , Zhang Yan-Jie , Mao Qiang-Bing , Li Qing
Published: February 2025

The Newtonian gravitational constant G is one of the most fundamental constants in nature. In G measurement with the angular acceleration feedback method, the largest error comes from the distances between the geometric centers of the source masses. In the on-going experiment, the silicon spheres with a more homogeneous density are used as the source masses. Here a scheme of measuring the geometric distances between the silicon spheres with the laser interferometer is proposed. The measurement principle is analyzed, and the error sources, such as the laser, the sphere, the alignment of optical path, and the environment are evaluated. With this method, the horizontal and vertical geometric distances can be measured with uncertainties of 11 nm and 9 nm, respectively. The simulation is performed to verify the theoretical model of measuring the distance, where the maximum deviation between the simulation result and the theoretical one is only −2.7 nm. When the sphericities of the four silicon spheres are at the level of 0.1 µm, the uncertainty of each distance after considering the sphericity is about 0.1 µm, corresponds to a combined uncertainty of 0.6 ppm for G measurement with the angular acceleration feedback method. This provides an effective method to reduce the measurement uncertainty of geometric distance between the silicon spheres, and makes it possible to measure G with a higher precision.
Existence of structural, electronic and magnetic correlations in Sm2NiMnO6 double perovskite
Authors: Majumder Supriyo , Tripathi Malvika , de Souza D O , Sagdeo A , Olivi L , Singh M N , Pal S , Phase D M , Choudhary R J
Published: February 2025

Coupling between different interactions allows the control of physical aspects in multifunctional materials by perturbing any degrees of freedom. Here, we aim to probe the correlation among structural, electronic, and magnetic observables in Sm2NiMnO6 (SNMO) ferromagnetic insulator double perovskite. Our employed methodology includes thermal evolution of x-ray diffraction, x-ray absorption spectroscopy, and bulk magnetometry. The magnetic ordering in SNMO adopts two transitions, at T
C = 160 K due to the ferromagnetic arrangement of Ni–Mn sublattice and at T
d = 34 K because of anti-parallel alignment of polarized Sm paramagnetic moments with respect to Ni–Mn network. Signature of Ni/Mn anti-site disorders are evidenced from short-range structure and magnetization analysis. The long-range as well as short-range crystal structure of SNMO undergo changes across T
C and T
d, observed through temperature dependent variation in Ni/Mn–O bonding characters. Hybridization between Ni, Mn 3d, O 2p electronic states show changes in the vicinity of magnetic transition. The change in crystal environments governs the magnetic response by imposing alteration in metal—ligand orbital overlap. On the other hand, it is observed that application of electric bias causes monotonic reduction in the saturation magnetic moment. By using these experimental methods, we demonstrate how the structural, electronic, and magnetic properties are correlated in SNMO, which makes it a potential platform for technological usage.
Efficient feature fusion network for small objects detection of traffic signs based on cross-dimensional and dual-domain information
Authors: Tao Hongfeng , Huang Zuojun , Wang Yue , Qiu Jier , Vladimir Stojanovic
Published: February 2025

The objectives in traffic sign detection and recognition scenario are predominantly small, which frequently result in missed and erroneous detection due to their limited information content and complex environment. To address these problems, this paper proposes a new network architecture cross-dimensional and dual-domain feature fusion-you only look once (CDFF-YOLO) which is integrated of various modules. For the purpose of overcoming the difficulty in extracting information from small objects, the Multi-dimension Spatial information Fusion module in the network are used to extract feature sequences at different dimensions by superposition. So as to address the issue of the loss of detail information of small objects, embed the Multi-branch Perceptual Attention module into the C2f module to capture feature information and enhance the global-local feature information exchange. In order to solve the issue of uneven illumination and occlusion in the detection scene. The DFF module is employed to transform and fuse the extracted small object feature information from the Space-to-depth convolution at the frequency and spatial domains, thereby enhancing the network’s capability to reconstruct and fuse feature information in dual-domains. The experimental data on the TT100K dataset demonstrate that the enhanced algorithm exhibits an increase of 3.7% in mAP@50, 4.8% in mAP@50:95, and a 4.5% and 3.7% rise in the average precision and average recall for small objects, respectively. Additionally, the frames per second remains 157. The improved algorithm also performs well on the CCTSDB dataset. It is evident that the CDFF-YOLO algorithm has the capacity to markedly enhance the detection efficacy of traffic signs, while maintaining optimal detection speed.
Integrated proprioceptive piezoelectric actuators for miniature robots and devices
Authors: Kabutz Heiko , Jayaram Kaushik
Published: February 2025

Piezoelectric motors have become a promising technology for the actuation of miniature robots. In this paper, we propose a novel integrated approach to measuring the deflection of piezoelectric actuators, by adding a thin film polyvinylidene fluoride (PVDF) as a dedicated sensor layer in a ceramic actuator laminate (PZT-5 H) to enable proprioception. We leverage our unique femtosecond laser micromachining process to pattern PVDF without altering its dielectric characteristics and validate this experimentally, including quantifying the changes with temperature and laser processing parameters, to develop a high-fidelity process for manufacturing proprioceptive actuators. The advantage of our approach lies in the requirement of minimal changes to the existing design process or fabrication workflow. To support the experimental results of actuator position tracking using the proposed approach, we derive first-principles-based theoretical expressions for modeling sensor and actuator functions and show that these predictions are in close alignment with experimental measurements. We then integrate the sensory actuators into a leg mechanism to demonstrate the use of proprioception capabilities for leg motion tracking, the detection of leg collisions with environmental obstacles and other surface interactions. Together, these experiments demonstrate the exciting potential of integrated proprioceptive sensing for robotic mechanisms by enabling servomotor-like functionality into traditional piezoelectric actuators, making them capable of closed-loop control in the near future. We conclude by examining possible limitations of this current method with potential mitigation strategies and emphasizing promising future prospects such as onboard closed-loop feedback control. We expect that the integration of PVDF sensors into actuators will enable the next generation of terrain-adaptive robots to adjust their movement to environmental changes, such as varying their gait in response to different ground surfaces.
A Neo-Aristotelian Approach to a Unified Theory of Physics
Authors: Kakkuri-Knuuttila Marja-Liisa
Published: February 2025

The core task of this paper is to demonstrate the heuristic merits of the Aristotelian philosophy of science as compared with the strict empiricism in constructing and justifying a unified theory of physics. The impetus for the study was the question of whether the success of the Dynamic Universe (DU) theory as a candidate for such a unification could be explained by energy as its basic notion (Suntola, T. 2018a, 2018b, 2020, 2021, 2022, 2024), while the other unificatory attempts (string theories, inflation theory, and loop quantum gravity), all based on the notion of force, appear to fail. DU’s reliance on Aristotle’s methodology of first principles and his potentiality-actuality metaphysics soon invited to explore DU’s Aristotelian presuppositions as an explanatory ground for its seeming success. A major weakness of empiricism is its rejection of metaphysical reflection, necessary for the revolutionary paradigm change in the unification project. While the empiricist negative stand towards metaphysics is based on its narrow conception of basis of knowledge and logical reasoning and the principle of methodological unity, Aristotelian solutions to these problems are difficult to refute. The Stagirite’s methodology of Saving the Appearances (SA), little known outside Aristotle scholarship, exposes ways of expanding the knowledge basis to make room for metaphysical knowledge. SA is valuable to our purposes here also by yielding a heuristic model for the discovery and justification of a unified theory of physics. Aristotle’s argument for the reality of potentiality in the form of an inference from a fact of life to its necessary presuppositions illustrates how to expand the empiricist premises-conclusion notion of logic. To specify the object of physics, the Aristotelian genus-species structure of reality exposes that the definition of the genus proximum constitutes the highest first principle of a theory. Applying Aristotle’s metaphysical notions of change and motion (dunamis, substance–attribute, matter-form), the genus proximum in DU turns out to be mass as prime substance, mass defined as the substance for the expression of energy. To conclude, I shall point to the need for modifying the Aristotelian metaphysical categories to allow room for the holism in DU. Having studied the heuristic principles underlying the DU theory, the paper contributes both to the emerging studies of the Meta-Empirical argument forms in physics and the recent Neo-Aristotelian approach in the philosophy of physics.