Railway noise barriers are an essential piece of infrastructure for reducing noise propagation.However,these barriers experience aerodynamic loads generated by high-speed trains,leading to dynamic effects that may com...Railway noise barriers are an essential piece of infrastructure for reducing noise propagation.However,these barriers experience aerodynamic loads generated by high-speed trains,leading to dynamic effects that may compromise their fatigue capacity.The most common structural design for railway noise barriers consists of vertical configurations of posts and panels.However,there have been few dynamic analyses of steel post/wood panel noise barriers under train-induced aerodynamic loads.This study used dynamic finite element analysis to assess the dynamic behavior of such noise barriers.Analysis of a 40-m-long noise barrier model and a triangular simplified load model,the latter of which effectively represented the detailed aerodynamic load,were first used to establish the model and input of the moving load during dynamic simulation.Then,the effects of different parameters on the dynamic response of the noise barrier were evaluated,including the damping ratio,the profile of the steel post,the span length of the panel,the barrier height,and the train speed.Gray relational analysis indicated that barrier height exhibited the highest correlations with the dynamic responses,followed by train speed,post profile,span length,and damping ratio.A reduction in the natural frequency and an increase in the train speed result in a higher peak response and more pronounced fluctuations between the nose and tail waves.The dynamic amplification factor(DAF)was found to be related to both the natural frequency and train speed.A model was proposed showing that the DAF significantly increases as the square of the natural frequency decreases and the cube of the train speed rises.展开更多
The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behav...The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.展开更多
Federated Learning(FL)provides an effective framework for efficient processing in vehicular edge computing.However,the dynamic and uncertain communication environment,along with the performance variations of vehicular...Federated Learning(FL)provides an effective framework for efficient processing in vehicular edge computing.However,the dynamic and uncertain communication environment,along with the performance variations of vehicular devices,affect the distribution and uploading processes of model parameters.In FL-assisted Internet of Vehicles(IoV)scenarios,challenges such as data heterogeneity,limited device resources,and unstable communication environments become increasingly prominent.These issues necessitate intelligent vehicle selection schemes to enhance training efficiency.Given this context,we propose a new scenario involving FL-assisted IoV systems under dynamic and uncertain communication conditions,and develop a dynamic interval multi-objective optimization algorithm to jointly optimize various factors including training experiments,system energy consumption,and bandwidth utilization to meet multi-criteria resource optimization requirements.For the problem at hand,we design a dynamic interval multi-objective optimization algorithm based on interval overlap detection.Simulation results demonstrate that our method outperforms other solutions in terms of accuracy,training cost,and server utilization.It effectively enhances training efficiency under wireless channel environments while rationally utilizing bandwidth resources,thus possessing significant scientific value and application potential in the field of IoV.展开更多
In multi-modal emotion recognition,excessive reliance on historical context often impedes the detection of emotional shifts,while modality heterogeneity and unimodal noise limit recognition performance.Existing method...In multi-modal emotion recognition,excessive reliance on historical context often impedes the detection of emotional shifts,while modality heterogeneity and unimodal noise limit recognition performance.Existing methods struggle to dynamically adjust cross-modal complementary strength to optimize fusion quality and lack effective mechanisms to model the dynamic evolution of emotions.To address these issues,we propose a multi-level dynamic gating and emotion transfer framework for multi-modal emotion recognition.A dynamic gating mechanism is applied across unimodal encoding,cross-modal alignment,and emotion transfer modeling,substantially improving noise robustness and feature alignment.First,we construct a unimodal encoder based on gated recurrent units and feature-selection gating to suppress intra-modal noise and enhance contextual representation.Second,we design a gated-attention crossmodal encoder that dynamically calibrates the complementary contributions of visual and audio modalities to the dominant textual features and eliminates redundant information.Finally,we introduce a gated enhanced emotion transfer module that explicitly models the temporal dependence of emotional evolution in dialogues via transfer gating and optimizes continuity modeling with a comparative learning loss.Experimental results demonstrate that the proposed method outperforms state-of-the-art models on the public MELD and IEMOCAP datasets.展开更多
The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of i...The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of its influence on fluid migration are of crucial importance.While previous studies have revealed that salinity changes can modulate fluid migration,the underlying mechanisms remain poorly understood.We employ molecular dynamics simulations to elucidate how salinity variations in ore-forming fluids modulate the adsorption onto calcite nanopore walls,thereby revealing the microscopic mechanisms governing ore fluid transport through calcite nano-fractures.The results show that the adsorption energy Eint of the solution on the calcite surface increased from -14,948.84±182.48 kcal/mol to -12,144.08±118.2 kcal/mol as salinity increased,which is conducive to the long-range transport of the fluid in the calcite nanopore.展开更多
Vitrimers belong to a class of polymeric materials capable of bond exchange reactions,showing great promise for environmental protection and sustainable development.However,studies on the coupling mechanism between th...Vitrimers belong to a class of polymeric materials capable of bond exchange reactions,showing great promise for environmental protection and sustainable development.However,studies on the coupling mechanism between the bond exchange kinetics and segmental dynamics near the glass transition temperature(T_(g))remain scarce.Herein,we employed molecular dynamics simulations to investigate the dynamic heterogeneity of the segment motion and bond exchange in vitrimers.The simulation results revealed that the bond exchange energy barrier exerts a much stronger influence on the bond exchange kinetics than on the segmental dynamics.At lower temperatures,slower segmental relaxation further constraind the bond exchange rate.Additionally,increasing the bond exchange energy barrier markedly enhanced the dynamic heterogeneity of segment motion.A close correlation was observed between heterogeneity and bond exchange.This study elucidated the coupling mechanism between bond exchange and segmental dynamics at the molecular scale,thereby providing a theoretical basis for designing vitrimer materials with tunable dynamic properties.展开更多
With the rapid development of intelligent navigation technology,efficient and safe path planning for mobile robots has become a core requirement.To address the challenges of complex dynamic environments,this paper pro...With the rapid development of intelligent navigation technology,efficient and safe path planning for mobile robots has become a core requirement.To address the challenges of complex dynamic environments,this paper proposes an intelligent path planning framework based on grid map modeling.First,an improved Safe and Smooth A*(SSA*)algorithm is employed for global path planning.By incorporating obstacle expansion and cornerpoint optimization,the proposed SSA*enhances the safety and smoothness of the planned path.Then,a Partitioned Dynamic Window Approach(PDWA)is integrated for local planning,which is triggered when dynamic or sudden static obstacles appear,enabling real-time obstacle avoidance and path adjustment.A unified objective function is constructed,considering path length,safety,and smoothness comprehensively.Multiple simulation experiments are conducted on typical port grid maps.The results demonstrate that the improved SSA*significantly reduces the number of expanded nodes and computation time in static environmentswhile generating smoother and safer paths.Meanwhile,the PDWA exhibits strong real-time performance and robustness in dynamic scenarios,achieving shorter paths and lower planning times compared to other graph search algorithms.The proposedmethodmaintains stable performance across maps of different scales and various port scenarios,verifying its practicality and potential for wider application.展开更多
Partial least squares (PLS) model maximizes the covariance between process variables and quality variables,making it widely used in quality-related fault detection.However,traditional PLS methods focus primarily on li...Partial least squares (PLS) model maximizes the covariance between process variables and quality variables,making it widely used in quality-related fault detection.However,traditional PLS methods focus primarily on linear processes,leading to poor performance in dynamic nonlinear processes.In this paper,a novel quality-related fault detection method,named DiCAE-PLS,is developed by combining dynamic-inner convolutional autoencoder with PLS.In the proposed DiCAE-PLS method,latent features are first extracted through dynamic-inner convolutional autoencoder (DiCAE) to capture process dynamics and nonlinearity from process variables.Then,a PLS model is established to build the relationship between the extracted latent features and the final product quality.To detect quality-related faults,Hotelling's T^(2) statistic is employed.The developed quality-related fault detection is applied to the widely used industrial benchmark of the Tennessee.展开更多
This paper prepared a novel as-cast W-Zr-Ti metallic ESM using high-frequency vacuum induction melting technique.The above ESM performs a typical elastic-brittle material feature and strain rate strengthening behavior...This paper prepared a novel as-cast W-Zr-Ti metallic ESM using high-frequency vacuum induction melting technique.The above ESM performs a typical elastic-brittle material feature and strain rate strengthening behavior.The specimens exhibit violent chemical reaction during the fracture process under the impact loading,and the size distribution of their residual debris follows Rosin-Rammler model.The dynamic fracture toughness is obtained by the fitting of debris length scale,approximately 1.87 MPa·m~(1/2).Microstructure observation on residual debris indicates that the failure process is determined by primary crack propagation under quasi-static compression,while it is affected by multiple cracks propagation in both particle and matrix in the case of dynamic impact.Impact test demonstrates that the novel energetic fragment performs brilliant penetration and combustion effect behind the front target,leading to the effective ignition of fuel tank.For the brittleness of as-cast W-ZrTi ESM,further study conducted bond-based peridynamic(BB-PD)C++computational code to simulate its fracture behavior during penetration.The BB-PD method successfully captured the fracture process and debris cloud formation of the energetic fragment.This paper explores a novel as-cast metallic ESM,and provides an available numerical avenue to the simulation of brittle energetic fragment.展开更多
Droplet impact dynamics on solid surfaces,which are ubiquitously present in aerospace engineering,energy systems,agricultural production,etc.,involve complex fluid–structure interactions.Herein,we employ a single-cam...Droplet impact dynamics on solid surfaces,which are ubiquitously present in aerospace engineering,energy systems,agricultural production,etc.,involve complex fluid–structure interactions.Herein,we employ a single-camera high-speed threedimensional digital image correlation system to quantify the full-field deformations of flexible thin films during droplet impact dynamics.Experimental results revealed that the substrate flexibility not only reduces the maximum spreading diameter by 10%but also modulates rebound dynamics via energy competition between kinetic energy and surface adhesion energy,suggesting that coupled deformation of the solid–fluid interface plays an important role in the dynamic progress.We propose the structure-coupled response number(Sn),a governing dimensionless parameter unifying droplet spreading on both rigid and flexible films,validated by a universal 1/2 scaling law.A theoretical criterion for droplet rebound on hydrophobic flexible thin films is derived and experimentally demonstrated,which achieves the precise control of droplet rebound/non-rebound mode.This work bridges the theories of droplet impact dynamics on rigid and flexible substrates,offering a robust strategy to govern the droplet impact behaviors.展开更多
MgO has been shown to facilitate the precipitation of MgO-rich crystalline phases within the MgO-CaO-Al_(2)O_(3)-SiO_(2)(MCAS)glassy inclusion system,which possesses a high liquidus temperature and a significant Young...MgO has been shown to facilitate the precipitation of MgO-rich crystalline phases within the MgO-CaO-Al_(2)O_(3)-SiO_(2)(MCAS)glassy inclusion system,which possesses a high liquidus temperature and a significant Young’s modulus.The underlying linkage between the structural evolution and the crystallization characteristics of the MCAS system was systematically investigated using molecular dynamics simulation and thermodynamic calculation.The results revealed that Mg^(2+) ions played a dual role,constructing networks through the formation of tricluster oxygens while consuming bridging oxygens(BOs)in a mechanism similar to Ca^(2+) ions.However,despite this dual role,the network connectivity was still decreased with the increase in MgO/(MgO+Al_(2)O_(3))(M/(M+A))and CaO/(CaO+SiO_(2))(C/(C+S))ratios,primarily due to the reduction in BOs.This microscopic structural evolution resulted in a reduction in viscosity and an enhancement of crystallization ability.Furthermore,the remarkable diffusion capability of Mg^(2+) ions,coupled with the increased proportion of 6-coordinated Mg^(2+)ions,unveiled the mechanism underlying the precipitation of MgSiO_(3) and Mg_(2)SiO_(4) crystals,which exhibited high Young’s moduli of 165.23 and 196.67 GPa,respectively.To prevent the precipitation of MgO-rich crystalline phases,it was crucial to maintain the M/(M+A)ratio below 0.42 and the C/(C+S)ratio below 0.16 within the MCAS system.展开更多
In this article,by employing the Hirota bilinear approach and the long wave limit method,we not only derive soliton solutions,lump solutions,and hybrid solutions for the(2+1)-dimensional Yu-Toda-Sasa-Fukuyama(YTSF)equ...In this article,by employing the Hirota bilinear approach and the long wave limit method,we not only derive soliton solutions,lump solutions,and hybrid solutions for the(2+1)-dimensional Yu-Toda-Sasa-Fukuyama(YTSF)equation,but also analyze the dynamical behaviors of nonlinear local wave propagation in shallow water.Firstly,based on the Hirota bilinear approach,one to four-order soliton solutions of the YTSF equation are obtained,and the effects of different parameters on the amplitude,propagation trajectory,and displacement of solitons are investigated.Secondly,using the long wave limit approach,one to three-order lump solutions and various physical quantities of the YTSF equation are derived.It is found that the real and imaginary parts of the parameter pi dominate the propagation trajectory and the shape of lump waves,respectively.Furthermore,we construct the hybrid solution for the YTSF equation,leading to the conclusion that the interaction between lumps and solitons constitutes an elastic collision.To intuitively understand the dynamic behaviors of these solutions,we conduct numerical simulations to present vivid three-dimensional visualizations.展开更多
The study presents an analysis of the spatiotemporal evolution of vegetation cover in the Izarene forest,using LANDSAT satellite images collected for the years 1984,2003,and 2022.The methodological approach is based o...The study presents an analysis of the spatiotemporal evolution of vegetation cover in the Izarene forest,using LANDSAT satellite images collected for the years 1984,2003,and 2022.The methodological approach is based on the use of ArcGIS 10.8 software for processing multispectral images,as well as the calculation of the Normalized Difference Vegetation Index(NDVI),which enables the observation of variations in vegetation cover over time.The findings show that biodiversity is pretty abundant,but they also show that some places with low vegetation density are under a lot of stress.Due in large part to overuse of natural resources,uncontrolled human activity,and environmental factors,these regions seem to be more vulnerable to degradation.However,a decrease in deforestation over the past 20 years is revealed by comparing the two periods(1984–2003 and 2003–2022).The participation of governmental agencies,especially the Department of Water and Forests,through concrete projects like reforestation,forest fire prevention,and awareness-raising campaigns among local communities,is responsible for this progress.In several areas,these measures have stabilized or even improved the state of the vegetation.The analysis emphasizes how crucial sustainable,integrated,and participatory management is to protecting the Izarene forest,which is a significant resource for maintaining the region’s ecological balance.展开更多
In response to the increasing demand for hadron therapy facilities,significant efforts have been directed toward enhancing the performance of high-gradient and high-transmission injectors for light ion beams.For carbo...In response to the increasing demand for hadron therapy facilities,significant efforts have been directed toward enhancing the performance of high-gradient and high-transmission injectors for light ion beams.For carbon ion irradiations,which offer greater radiobiological efficiency in tumor treatment,recent research has focused on developing high-production sources of fully stripped C^(6+)ions and highly compact,high-frequency RFQ cavities.This study explores the design possibilities of a carbon ion acceleration section using 750 MHz Interdigital H-mode Drift Tube Linacs(IH-DTLs)as a high-efficiency solution for accelerating ions in the 5-10 MeV per nucleon energy range.A particle-tracking routine based on the TRAVEL code was developed to design the acceleration line through a tailored KONUS-type configuration.Three design solutions were proposed and compared,exploring different alternatives regarding the use of a MEBT to match the output beam phase space of the RFQ to the optics of the line,as well as varying considerations for magnetic systems to focus the beam.Additionally,the compatibility of the proposed solutions with the existing design of the carbon ion bent-linac for hadron therapy was assessed.展开更多
Like-charge pairing is a physical manifestation of the unique solvation properties of certain ion pairs in water.Water's high dielectric constant and related charge screening capability significantly influence the...Like-charge pairing is a physical manifestation of the unique solvation properties of certain ion pairs in water.Water's high dielectric constant and related charge screening capability significantly influence the interaction between like-charged ions,with the possibility to transform it-in exceptional cases when noncovalent interactions are involved-from repulsion to attraction.Guanidinium cations(Gdm^(+))represent a quintessential example of such like-charge pairing due to their specific geometry and electronic structure.In this work,we present experimental validation and quantification of Gdm^(+)-Gdm contact ion pairing in water utilizing nuclear magnetic resonance(NMR)spectroscopy complemented by molecular dynamics(MD)simulations and density functional theory(DFT)calculations.The observed Gdm^(+)-Gdm^(+)interaction is attractive albeit weak-about 0.5 kJ·mol^(-1)-which aligns with theoretical estimation from MD simulations.We contrast the behavior of Gdm^(+) with that of NH_(4)^(+) cations,which exhibit no contact ion pairing in water.DFT calculations predict that the NMR chemical shift of Gdm^(+) dimers is different than that of monomers,in agreement with NMR titration curves that display a nonlinear Langmuir-like behavior.Additionally,we conducted cryo-electron microscopy-to our knowledge,for the first time-on concentrated oligoarginines R9,which,unlike nona-lysines K9,exhibit aggregation in water.These results point to like charge pairing of the guanidinium side chain groups,as corroborated also by MD simulations and free energy calculations.展开更多
Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials.In this study,four linear low-density polyethylenes(LLD...Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials.In this study,four linear low-density polyethylenes(LLDPEs)with comparable molecular weights but different short-chain branch(SCB)contents(ranging of 5-66 per 1000 carbon atoms)were modified via dynamic melt mixing using 2 wt% benzoyl peroxide at 145℃ and 50 r/min for 30 min.The influence of SCB content on the processability and structure of the resulting products was systematically investigated.All modified products exhibited good melt processability with melt flow rates(MFR)ranging from 0.46 g/10min to 1.07 g/10min.Products derived from low-SCB LLDPEs showed a lower MFR,higher cross-linking content,a larger number of long-chain branches,and a higher degree of benzoyl grafting.In contrast,those produced from high-SCB LLDPEs exhibited improved processability,reduced cross-linking,fewer long-chain branches,and lower benzoyl grafting levels.A detailed structural investigation of the soluble and insoluble fractions,which were separated using trichlorobenzene fractionation,was conducted to analyze the structural features of various modified products and demonstrate that the SCB content(i.e.,tertiary carbon density)significantly influences radical coupling during dynamic modification.Elevated tertiary carbon density,by introducing greater steric hindrance,suppresses radical coupling during dynamic modification,thereby reducing the efficiency of both crosslinking and peroxide fragment grafting.These findings provide new insights into the structure-reactivity relationships in peroxide-induced polyethylene modification and lay the foundation for tailoring material properties via dynamic processing.展开更多
THE mechanical response and deformation mechanisms of pure nickel under nanoindentation were systematically investigated using molecular dynamics(MD)simulations,with a particular focus on the novel interplay between c...THE mechanical response and deformation mechanisms of pure nickel under nanoindentation were systematically investigated using molecular dynamics(MD)simulations,with a particular focus on the novel interplay between crystallographic orientation,grain boundary(GB)proximity,and pore characteristics(size/location).This study compares single-crystal nickel models along[100],[110],and[111]orientations with equiaxed polycrystalline models containing 0,1,and 2.5 nm pores in surface and subsurface configurations.Our results reveal that crystallographic anisotropy manifests as a 24.4%higher elastic modulus and 22.2%greater hardness in[111]-oriented single crystals compared to[100].Pore-GB synergistic effects are found to dominate the deformation behavior:2.5 nm subsurface pores reduce hardness by 25.2%through stress concentration and dislocation annihilation at GBs,whereas surface pores enable mechanical recovery via accelerated dislocation generation post-collapse.Additionally,size-dependent deformation regimes were identified,with 1 nm pores inducing negligible perturbation due to rapid atomic rearrangement,in contrast with persistent softening in 2.5 nm pores.These findings establish atomic-scale design principles for defect engineering in nickel-based aerospace components,demonstrating how crystallographic orientation,pore configuration,and GB interactions collectively govern nanoindentation behavior.展开更多
To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals ...To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals during coal mass loading.By integrating innovative analytical approaches,introducing quantitative evaluation indices,and developing a charge–stress inversion model,and incorporating underground monitoring practices,significant progress has been achieved in elucidating the correlation between stress variations and charge signals throughout the entire coal mass fracturing process.First,in the field of stress–charge correlation analysis,empirical mode decomposition(EMD)was combined with wavelet coherence analysis for the first time,enabling the removal of slow-varying stress trends while retaining high-frequency fluctuations.This approach allowed for the quantitative characterization of the evolution of coherence between stress variations and charge fluctuations across multiple time scales.Second,coherence skewness and the proportion of high-coherence intervals were innovatively introduced to examine the influence of time scale selection on correlation results.On this basis,a criterion for determining the near-optimal observation scale of charge signals was proposed,providing a quantitative reference for time scale selection in similar signal analyses.Finally,by correlating charge signals with coal damage factors and stress states,a charge-based damage evolution equation was established to achieve effective stress inversion.Combined with in situ monitoring of stress and charge in roadway surrounding rock,this approach revealed the correlation characteristics of stress and charge intensity responses during the dynamic fracturing process.The results indicate,first,that charge signals are not significantly correlated with the absolute stress level of coal but are directly associated with stress variations following coal damage and failure,with the amplitude of charge fluctuations increasing alongside stress fluctuations.Second,coherence between stress and charge signals varies markedly across time scales,with excessively small or large scales leading to distortion,and the scale corresponding to the peak proportion of intervals with coherence>0.8 was identified as the near-optimal observation scale.Third,charge signals can effectively characterize coal damage factors,and the established damage evolution equation can effectively invert stress variation trends.Fourth,in underground roadways,zones of dynamic fracturing in surrounding rock are commonly located in areas where stress concentration overlaps with regions of high charge intensity,further confirming the strong consistency between charge and stress variations.These findings improve the theoretical framework of charge signal responses in loaded coal and provide a scientific basis for precise“stress-charge”monitoring of dynamic disasters,offering practical potential for engineering applications.展开更多
Reinforced concrete(RC)columns are often subjected to off-central explosion due to the uncertainty of blast locations.However,few studies have focused on the dynamic response of RC columns under offcentral explosions....Reinforced concrete(RC)columns are often subjected to off-central explosion due to the uncertainty of blast locations.However,few studies have focused on the dynamic response of RC columns under offcentral explosions.A field blast experiment was conducted under close-in explosion with varying detonation offset distances(0 m,0.5 m,and 1 m),the overpressure load and dynamic responses of the full-scale RC columns were measured.Compared with the centrally detonated condition,a relative offset distance of 1.67 decreases the maximum and residual deflections of the RC column by 16.8%and 21.4%,respectively,while increasing the maximum and residual support rotations by 24.7%and 17.8%.Based on the experimental results,a theoretical model was proposed that considers the detonation location and charge mass,boundary conditions,axial compression ratio and material properties.The theoretical model exhibited good agreement with the experimental results,with prediction errors below 10%for both maximum and residual deflection.The effects of parameters were analyzed,and it indicated that an increase in offset distance results in decreased maximum and residual deflections but an increased support angle,thereby exacerbating damage.Higher axial load ratio,span-depth ratio,and longitudinal reinforcement ratio reduce both deflections and support angle.Additionally,a rapid method to predict the maximum and residual deflection of RC columns under off-central blast loading was also proposed based on the Generalized Regression Neural Network(GRNN).Eleven features which related to the RC column properties and the blast characteristics were used in the training process of GRNN,and accurate predictions were achieved with prediction errors within 20%.This study fills the gap in predicting the dynamic response of RC columns under off-central explosion,providing valuable references for blast-resistant design.展开更多
Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal sca...Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal scale tasks.In this study,we report an OECT-based neuromorphic device with tunable relaxation time(τ)by introducing an additional vertical back-gate electrode into a planar structure.The dual-gate design enablesτreconfiguration from 93 to 541 ms.The tunable relaxation behaviors can be attributed to the combined effects of planar-gate induced electrochemical doping and back-gateinduced electrostatic coupling,as verified by electrochemical impedance spectroscopy analysis.Furthermore,we used theτ-tunable OECT devices as physical reservoirs in the RC system for intelligent driving trajectory prediction,achieving a significant improvement in prediction accuracy from below 69%to 99%.The results demonstrate that theτ-tunable OECT shows a promising candidate for multi-temporal scale neuromorphic computing applications.展开更多
基金financially supported by the Swedish Transport Administration(Trafikverket)through the“Excellence Area 4”and FOI-BBT program(Grant Nos.BBT-2019-022 and BBT-TRV 2024/132497).
文摘Railway noise barriers are an essential piece of infrastructure for reducing noise propagation.However,these barriers experience aerodynamic loads generated by high-speed trains,leading to dynamic effects that may compromise their fatigue capacity.The most common structural design for railway noise barriers consists of vertical configurations of posts and panels.However,there have been few dynamic analyses of steel post/wood panel noise barriers under train-induced aerodynamic loads.This study used dynamic finite element analysis to assess the dynamic behavior of such noise barriers.Analysis of a 40-m-long noise barrier model and a triangular simplified load model,the latter of which effectively represented the detailed aerodynamic load,were first used to establish the model and input of the moving load during dynamic simulation.Then,the effects of different parameters on the dynamic response of the noise barrier were evaluated,including the damping ratio,the profile of the steel post,the span length of the panel,the barrier height,and the train speed.Gray relational analysis indicated that barrier height exhibited the highest correlations with the dynamic responses,followed by train speed,post profile,span length,and damping ratio.A reduction in the natural frequency and an increase in the train speed result in a higher peak response and more pronounced fluctuations between the nose and tail waves.The dynamic amplification factor(DAF)was found to be related to both the natural frequency and train speed.A model was proposed showing that the DAF significantly increases as the square of the natural frequency decreases and the cube of the train speed rises.
基金financially supported by the National Natural Science Foundation of China(Nos.22341304,22303100 and 12205270)the National Key R&D Program of China(Nos.2023YFA1008800 and 2020YFA0713601)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC0180303)。
文摘The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.
基金supported in part by the Central Guidance for Local Science and Technology Development Funds under Grant No.YDZJSX2025D049Shanxi Provincial Graduate Innovation Research Program under Grant No.2024KY652.
文摘Federated Learning(FL)provides an effective framework for efficient processing in vehicular edge computing.However,the dynamic and uncertain communication environment,along with the performance variations of vehicular devices,affect the distribution and uploading processes of model parameters.In FL-assisted Internet of Vehicles(IoV)scenarios,challenges such as data heterogeneity,limited device resources,and unstable communication environments become increasingly prominent.These issues necessitate intelligent vehicle selection schemes to enhance training efficiency.Given this context,we propose a new scenario involving FL-assisted IoV systems under dynamic and uncertain communication conditions,and develop a dynamic interval multi-objective optimization algorithm to jointly optimize various factors including training experiments,system energy consumption,and bandwidth utilization to meet multi-criteria resource optimization requirements.For the problem at hand,we design a dynamic interval multi-objective optimization algorithm based on interval overlap detection.Simulation results demonstrate that our method outperforms other solutions in terms of accuracy,training cost,and server utilization.It effectively enhances training efficiency under wireless channel environments while rationally utilizing bandwidth resources,thus possessing significant scientific value and application potential in the field of IoV.
基金funded by“the Fanying Special Program of the National Natural Science Foundation of China,grant number 62341307”“the Scientific research project of Jiangxi Provincial Department of Education,grant number GJJ200839”“theDoctoral startup fund of JiangxiUniversity of Technology,grant number 205200100402”.
文摘In multi-modal emotion recognition,excessive reliance on historical context often impedes the detection of emotional shifts,while modality heterogeneity and unimodal noise limit recognition performance.Existing methods struggle to dynamically adjust cross-modal complementary strength to optimize fusion quality and lack effective mechanisms to model the dynamic evolution of emotions.To address these issues,we propose a multi-level dynamic gating and emotion transfer framework for multi-modal emotion recognition.A dynamic gating mechanism is applied across unimodal encoding,cross-modal alignment,and emotion transfer modeling,substantially improving noise robustness and feature alignment.First,we construct a unimodal encoder based on gated recurrent units and feature-selection gating to suppress intra-modal noise and enhance contextual representation.Second,we design a gated-attention crossmodal encoder that dynamically calibrates the complementary contributions of visual and audio modalities to the dominant textual features and eliminates redundant information.Finally,we introduce a gated enhanced emotion transfer module that explicitly models the temporal dependence of emotional evolution in dialogues via transfer gating and optimizes continuity modeling with a comparative learning loss.Experimental results demonstrate that the proposed method outperforms state-of-the-art models on the public MELD and IEMOCAP datasets.
基金financed jointly by the National Major Science and Technology Special Project on Deep Earth Exploration(2024ZD1001701-5)the National Natural Science Foundation of China(42472127,42172086)+2 种基金the Yunnan Major Project of Basic Research(202401BN070001-002)Yunnan Mineral Resources Prediction and Evaluation Engineering Research Center(2011)Innovation Team Program of Kunming University of Science and Technology,Yunnan Province。
文摘The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of its influence on fluid migration are of crucial importance.While previous studies have revealed that salinity changes can modulate fluid migration,the underlying mechanisms remain poorly understood.We employ molecular dynamics simulations to elucidate how salinity variations in ore-forming fluids modulate the adsorption onto calcite nanopore walls,thereby revealing the microscopic mechanisms governing ore fluid transport through calcite nano-fractures.The results show that the adsorption energy Eint of the solution on the calcite surface increased from -14,948.84±182.48 kcal/mol to -12,144.08±118.2 kcal/mol as salinity increased,which is conducive to the long-range transport of the fluid in the calcite nanopore.
基金financially supported by the National Natural Science Foundation of China(Nos.52173020 and 52573023)。
文摘Vitrimers belong to a class of polymeric materials capable of bond exchange reactions,showing great promise for environmental protection and sustainable development.However,studies on the coupling mechanism between the bond exchange kinetics and segmental dynamics near the glass transition temperature(T_(g))remain scarce.Herein,we employed molecular dynamics simulations to investigate the dynamic heterogeneity of the segment motion and bond exchange in vitrimers.The simulation results revealed that the bond exchange energy barrier exerts a much stronger influence on the bond exchange kinetics than on the segmental dynamics.At lower temperatures,slower segmental relaxation further constraind the bond exchange rate.Additionally,increasing the bond exchange energy barrier markedly enhanced the dynamic heterogeneity of segment motion.A close correlation was observed between heterogeneity and bond exchange.This study elucidated the coupling mechanism between bond exchange and segmental dynamics at the molecular scale,thereby providing a theoretical basis for designing vitrimer materials with tunable dynamic properties.
文摘With the rapid development of intelligent navigation technology,efficient and safe path planning for mobile robots has become a core requirement.To address the challenges of complex dynamic environments,this paper proposes an intelligent path planning framework based on grid map modeling.First,an improved Safe and Smooth A*(SSA*)algorithm is employed for global path planning.By incorporating obstacle expansion and cornerpoint optimization,the proposed SSA*enhances the safety and smoothness of the planned path.Then,a Partitioned Dynamic Window Approach(PDWA)is integrated for local planning,which is triggered when dynamic or sudden static obstacles appear,enabling real-time obstacle avoidance and path adjustment.A unified objective function is constructed,considering path length,safety,and smoothness comprehensively.Multiple simulation experiments are conducted on typical port grid maps.The results demonstrate that the improved SSA*significantly reduces the number of expanded nodes and computation time in static environmentswhile generating smoother and safer paths.Meanwhile,the PDWA exhibits strong real-time performance and robustness in dynamic scenarios,achieving shorter paths and lower planning times compared to other graph search algorithms.The proposedmethodmaintains stable performance across maps of different scales and various port scenarios,verifying its practicality and potential for wider application.
基金supported in part by the National Natural Science Foundation of China(62573387)the Natural Science Foundation of Zhejiang province,China(LY24F030004)the Fundamental Research Funds of Zhejiang Sci-Tech University(25222139-Y).
文摘Partial least squares (PLS) model maximizes the covariance between process variables and quality variables,making it widely used in quality-related fault detection.However,traditional PLS methods focus primarily on linear processes,leading to poor performance in dynamic nonlinear processes.In this paper,a novel quality-related fault detection method,named DiCAE-PLS,is developed by combining dynamic-inner convolutional autoencoder with PLS.In the proposed DiCAE-PLS method,latent features are first extracted through dynamic-inner convolutional autoencoder (DiCAE) to capture process dynamics and nonlinearity from process variables.Then,a PLS model is established to build the relationship between the extracted latent features and the final product quality.To detect quality-related faults,Hotelling's T^(2) statistic is employed.The developed quality-related fault detection is applied to the widely used industrial benchmark of the Tennessee.
文摘This paper prepared a novel as-cast W-Zr-Ti metallic ESM using high-frequency vacuum induction melting technique.The above ESM performs a typical elastic-brittle material feature and strain rate strengthening behavior.The specimens exhibit violent chemical reaction during the fracture process under the impact loading,and the size distribution of their residual debris follows Rosin-Rammler model.The dynamic fracture toughness is obtained by the fitting of debris length scale,approximately 1.87 MPa·m~(1/2).Microstructure observation on residual debris indicates that the failure process is determined by primary crack propagation under quasi-static compression,while it is affected by multiple cracks propagation in both particle and matrix in the case of dynamic impact.Impact test demonstrates that the novel energetic fragment performs brilliant penetration and combustion effect behind the front target,leading to the effective ignition of fuel tank.For the brittleness of as-cast W-ZrTi ESM,further study conducted bond-based peridynamic(BB-PD)C++computational code to simulate its fracture behavior during penetration.The BB-PD method successfully captured the fracture process and debris cloud formation of the energetic fragment.This paper explores a novel as-cast metallic ESM,and provides an available numerical avenue to the simulation of brittle energetic fragment.
基金supported by the National Key R&D Program of China(grant nos.2022YFF0503500 and 2022YFA1203200)the Guangdong Basic and Applied Basic Research Foundation(grant no.2023A1515011784)+2 种基金the National Natural Science Foundation of China(grant no.12032019)the Strategic Priority Research Program of Chinese Academy of Sciences(grant nos.XDB0620101 and XDB0620103)the Youth Innovation Promotion Association,Chinese Academy of Sciences(no.2020020).
文摘Droplet impact dynamics on solid surfaces,which are ubiquitously present in aerospace engineering,energy systems,agricultural production,etc.,involve complex fluid–structure interactions.Herein,we employ a single-camera high-speed threedimensional digital image correlation system to quantify the full-field deformations of flexible thin films during droplet impact dynamics.Experimental results revealed that the substrate flexibility not only reduces the maximum spreading diameter by 10%but also modulates rebound dynamics via energy competition between kinetic energy and surface adhesion energy,suggesting that coupled deformation of the solid–fluid interface plays an important role in the dynamic progress.We propose the structure-coupled response number(Sn),a governing dimensionless parameter unifying droplet spreading on both rigid and flexible films,validated by a universal 1/2 scaling law.A theoretical criterion for droplet rebound on hydrophobic flexible thin films is derived and experimentally demonstrated,which achieves the precise control of droplet rebound/non-rebound mode.This work bridges the theories of droplet impact dynamics on rigid and flexible substrates,offering a robust strategy to govern the droplet impact behaviors.
基金support from the National Key R&D Program of China(Grant Nos.2023YFB3709900 and 2023YFB3709903)the National Natural Science Foundation of China(Grant Nos.52174293 and U22A20171)+1 种基金the High Steel Center(HSC)at North China University of TechnologyUniversity of Science and Technology Beijing(USTB).
文摘MgO has been shown to facilitate the precipitation of MgO-rich crystalline phases within the MgO-CaO-Al_(2)O_(3)-SiO_(2)(MCAS)glassy inclusion system,which possesses a high liquidus temperature and a significant Young’s modulus.The underlying linkage between the structural evolution and the crystallization characteristics of the MCAS system was systematically investigated using molecular dynamics simulation and thermodynamic calculation.The results revealed that Mg^(2+) ions played a dual role,constructing networks through the formation of tricluster oxygens while consuming bridging oxygens(BOs)in a mechanism similar to Ca^(2+) ions.However,despite this dual role,the network connectivity was still decreased with the increase in MgO/(MgO+Al_(2)O_(3))(M/(M+A))and CaO/(CaO+SiO_(2))(C/(C+S))ratios,primarily due to the reduction in BOs.This microscopic structural evolution resulted in a reduction in viscosity and an enhancement of crystallization ability.Furthermore,the remarkable diffusion capability of Mg^(2+) ions,coupled with the increased proportion of 6-coordinated Mg^(2+)ions,unveiled the mechanism underlying the precipitation of MgSiO_(3) and Mg_(2)SiO_(4) crystals,which exhibited high Young’s moduli of 165.23 and 196.67 GPa,respectively.To prevent the precipitation of MgO-rich crystalline phases,it was crucial to maintain the M/(M+A)ratio below 0.42 and the C/(C+S)ratio below 0.16 within the MCAS system.
基金Supported by the National Natural Science Foundation of China(12001424,12271324)the Natural Science Basic research program of Shaanxi Province(2021JZ-21)+1 种基金the China Postdoctoral Science Foundation(2020M673332)Xi’an University,Xi’an Science and Technology Plan Wutongshu Technology Transfer Action Innovation Team(25WTZD07)。
文摘In this article,by employing the Hirota bilinear approach and the long wave limit method,we not only derive soliton solutions,lump solutions,and hybrid solutions for the(2+1)-dimensional Yu-Toda-Sasa-Fukuyama(YTSF)equation,but also analyze the dynamical behaviors of nonlinear local wave propagation in shallow water.Firstly,based on the Hirota bilinear approach,one to four-order soliton solutions of the YTSF equation are obtained,and the effects of different parameters on the amplitude,propagation trajectory,and displacement of solitons are investigated.Secondly,using the long wave limit approach,one to three-order lump solutions and various physical quantities of the YTSF equation are derived.It is found that the real and imaginary parts of the parameter pi dominate the propagation trajectory and the shape of lump waves,respectively.Furthermore,we construct the hybrid solution for the YTSF equation,leading to the conclusion that the interaction between lumps and solitons constitutes an elastic collision.To intuitively understand the dynamic behaviors of these solutions,we conduct numerical simulations to present vivid three-dimensional visualizations.
文摘The study presents an analysis of the spatiotemporal evolution of vegetation cover in the Izarene forest,using LANDSAT satellite images collected for the years 1984,2003,and 2022.The methodological approach is based on the use of ArcGIS 10.8 software for processing multispectral images,as well as the calculation of the Normalized Difference Vegetation Index(NDVI),which enables the observation of variations in vegetation cover over time.The findings show that biodiversity is pretty abundant,but they also show that some places with low vegetation density are under a lot of stress.Due in large part to overuse of natural resources,uncontrolled human activity,and environmental factors,these regions seem to be more vulnerable to degradation.However,a decrease in deforestation over the past 20 years is revealed by comparing the two periods(1984–2003 and 2003–2022).The participation of governmental agencies,especially the Department of Water and Forests,through concrete projects like reforestation,forest fire prevention,and awareness-raising campaigns among local communities,is responsible for this progress.In several areas,these measures have stabilized or even improved the state of the vegetation.The analysis emphasizes how crucial sustainable,integrated,and participatory management is to protecting the Izarene forest,which is a significant resource for maintaining the region’s ecological balance.
基金Project co-funded by European Union in the context of the precommercial public procurement of RD services managed by CDTI E.P.Eco-funded by the European Regional Development Fund(ERDF)as part of the project for the development of a Compact Linear Accelerator for Hadrontherapy,Exp.CPP 03/2023 AB(DCCPI/OCPI)。
文摘In response to the increasing demand for hadron therapy facilities,significant efforts have been directed toward enhancing the performance of high-gradient and high-transmission injectors for light ion beams.For carbon ion irradiations,which offer greater radiobiological efficiency in tumor treatment,recent research has focused on developing high-production sources of fully stripped C^(6+)ions and highly compact,high-frequency RFQ cavities.This study explores the design possibilities of a carbon ion acceleration section using 750 MHz Interdigital H-mode Drift Tube Linacs(IH-DTLs)as a high-efficiency solution for accelerating ions in the 5-10 MeV per nucleon energy range.A particle-tracking routine based on the TRAVEL code was developed to design the acceleration line through a tailored KONUS-type configuration.Three design solutions were proposed and compared,exploring different alternatives regarding the use of a MEBT to match the output beam phase space of the RFQ to the optics of the line,as well as varying considerations for magnetic systems to focus the beam.Additionally,the compatibility of the proposed solutions with the existing design of the carbon ion bent-linac for hadron therapy was assessed.
基金support from the project“National Institute of Virology and Bacteriology(Program EXCELES,ID Project No.LX22NPO5103)Funded by the European Union-Next Generation EU".D.B.also acknowledges VSB-Technical University of Ostrava,IT4Innovations National Supercomputing Center,Czech Republic,for awarding this project access to the LUMI supercomputer,owned by the EuroHPC Joint Undertaking,hosted by CSC(Finland)and the LUMI consortium through the Ministry of Education,Youth and Sports of the Czech Republic through the e-INFRA CZ(Grant ID:90254)+4 种基金project OPEN-35-3.M.V.and J.H.acknowledge the Czech Science Foundation for support via grant number 25-16117S and the project"The Energy Conversion and Storage"funded as project No.CZ.02.01.01/00/22_008/0004617 by Programme Johannes Amos Comeniuscall Excellent Research.M.V.also acknowledges support by the Ministry of Education,Youth and Sports of the Czech Republic through the e-INFRA CZ(ID:90254)Project OPEN-30-53.P.J.acknowledges support from the European Research Council via an ERC Advanced Grant no.101095957The authors would like to acknowledge the contribution of COST Action CA21169,supported by COST(European Cooperation in Science and Technology).
文摘Like-charge pairing is a physical manifestation of the unique solvation properties of certain ion pairs in water.Water's high dielectric constant and related charge screening capability significantly influence the interaction between like-charged ions,with the possibility to transform it-in exceptional cases when noncovalent interactions are involved-from repulsion to attraction.Guanidinium cations(Gdm^(+))represent a quintessential example of such like-charge pairing due to their specific geometry and electronic structure.In this work,we present experimental validation and quantification of Gdm^(+)-Gdm contact ion pairing in water utilizing nuclear magnetic resonance(NMR)spectroscopy complemented by molecular dynamics(MD)simulations and density functional theory(DFT)calculations.The observed Gdm^(+)-Gdm^(+)interaction is attractive albeit weak-about 0.5 kJ·mol^(-1)-which aligns with theoretical estimation from MD simulations.We contrast the behavior of Gdm^(+) with that of NH_(4)^(+) cations,which exhibit no contact ion pairing in water.DFT calculations predict that the NMR chemical shift of Gdm^(+) dimers is different than that of monomers,in agreement with NMR titration curves that display a nonlinear Langmuir-like behavior.Additionally,we conducted cryo-electron microscopy-to our knowledge,for the first time-on concentrated oligoarginines R9,which,unlike nona-lysines K9,exhibit aggregation in water.These results point to like charge pairing of the guanidinium side chain groups,as corroborated also by MD simulations and free energy calculations.
基金financially supported by the Science and Technology Project of PetroChina Company Limited,China(No.2022DJ6314)the National Natural Science Foundation of China(No.52173056)。
文摘Dynamic melt modification of polyethylene via the direct grafting of peroxide fragments shows promise for the development of processable functionalized materials.In this study,four linear low-density polyethylenes(LLDPEs)with comparable molecular weights but different short-chain branch(SCB)contents(ranging of 5-66 per 1000 carbon atoms)were modified via dynamic melt mixing using 2 wt% benzoyl peroxide at 145℃ and 50 r/min for 30 min.The influence of SCB content on the processability and structure of the resulting products was systematically investigated.All modified products exhibited good melt processability with melt flow rates(MFR)ranging from 0.46 g/10min to 1.07 g/10min.Products derived from low-SCB LLDPEs showed a lower MFR,higher cross-linking content,a larger number of long-chain branches,and a higher degree of benzoyl grafting.In contrast,those produced from high-SCB LLDPEs exhibited improved processability,reduced cross-linking,fewer long-chain branches,and lower benzoyl grafting levels.A detailed structural investigation of the soluble and insoluble fractions,which were separated using trichlorobenzene fractionation,was conducted to analyze the structural features of various modified products and demonstrate that the SCB content(i.e.,tertiary carbon density)significantly influences radical coupling during dynamic modification.Elevated tertiary carbon density,by introducing greater steric hindrance,suppresses radical coupling during dynamic modification,thereby reducing the efficiency of both crosslinking and peroxide fragment grafting.These findings provide new insights into the structure-reactivity relationships in peroxide-induced polyethylene modification and lay the foundation for tailoring material properties via dynamic processing.
基金The National Natural Science Foundation of China(Grant No.12462006)Beijing Institute of Structure and Environment Engineering Joint Innovation Fund(No.BQJJ202414).
文摘THE mechanical response and deformation mechanisms of pure nickel under nanoindentation were systematically investigated using molecular dynamics(MD)simulations,with a particular focus on the novel interplay between crystallographic orientation,grain boundary(GB)proximity,and pore characteristics(size/location).This study compares single-crystal nickel models along[100],[110],and[111]orientations with equiaxed polycrystalline models containing 0,1,and 2.5 nm pores in surface and subsurface configurations.Our results reveal that crystallographic anisotropy manifests as a 24.4%higher elastic modulus and 22.2%greater hardness in[111]-oriented single crystals compared to[100].Pore-GB synergistic effects are found to dominate the deformation behavior:2.5 nm subsurface pores reduce hardness by 25.2%through stress concentration and dislocation annihilation at GBs,whereas surface pores enable mechanical recovery via accelerated dislocation generation post-collapse.Additionally,size-dependent deformation regimes were identified,with 1 nm pores inducing negligible perturbation due to rapid atomic rearrangement,in contrast with persistent softening in 2.5 nm pores.These findings establish atomic-scale design principles for defect engineering in nickel-based aerospace components,demonstrating how crystallographic orientation,pore configuration,and GB interactions collectively govern nanoindentation behavior.
基金supported by the Research Fund of the National Natural Science Foundation of China(No.52374205)the Fundamental Research Project of the Educational Department of Liaoning Province(No.JYTMS20230793)the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.YJY-XD-2024-A-016).
文摘To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals during coal mass loading.By integrating innovative analytical approaches,introducing quantitative evaluation indices,and developing a charge–stress inversion model,and incorporating underground monitoring practices,significant progress has been achieved in elucidating the correlation between stress variations and charge signals throughout the entire coal mass fracturing process.First,in the field of stress–charge correlation analysis,empirical mode decomposition(EMD)was combined with wavelet coherence analysis for the first time,enabling the removal of slow-varying stress trends while retaining high-frequency fluctuations.This approach allowed for the quantitative characterization of the evolution of coherence between stress variations and charge fluctuations across multiple time scales.Second,coherence skewness and the proportion of high-coherence intervals were innovatively introduced to examine the influence of time scale selection on correlation results.On this basis,a criterion for determining the near-optimal observation scale of charge signals was proposed,providing a quantitative reference for time scale selection in similar signal analyses.Finally,by correlating charge signals with coal damage factors and stress states,a charge-based damage evolution equation was established to achieve effective stress inversion.Combined with in situ monitoring of stress and charge in roadway surrounding rock,this approach revealed the correlation characteristics of stress and charge intensity responses during the dynamic fracturing process.The results indicate,first,that charge signals are not significantly correlated with the absolute stress level of coal but are directly associated with stress variations following coal damage and failure,with the amplitude of charge fluctuations increasing alongside stress fluctuations.Second,coherence between stress and charge signals varies markedly across time scales,with excessively small or large scales leading to distortion,and the scale corresponding to the peak proportion of intervals with coherence>0.8 was identified as the near-optimal observation scale.Third,charge signals can effectively characterize coal damage factors,and the established damage evolution equation can effectively invert stress variation trends.Fourth,in underground roadways,zones of dynamic fracturing in surrounding rock are commonly located in areas where stress concentration overlaps with regions of high charge intensity,further confirming the strong consistency between charge and stress variations.These findings improve the theoretical framework of charge signal responses in loaded coal and provide a scientific basis for precise“stress-charge”monitoring of dynamic disasters,offering practical potential for engineering applications.
基金financially supported by the National Natural Science Foundation of China(Grants No.12472399)。
文摘Reinforced concrete(RC)columns are often subjected to off-central explosion due to the uncertainty of blast locations.However,few studies have focused on the dynamic response of RC columns under offcentral explosions.A field blast experiment was conducted under close-in explosion with varying detonation offset distances(0 m,0.5 m,and 1 m),the overpressure load and dynamic responses of the full-scale RC columns were measured.Compared with the centrally detonated condition,a relative offset distance of 1.67 decreases the maximum and residual deflections of the RC column by 16.8%and 21.4%,respectively,while increasing the maximum and residual support rotations by 24.7%and 17.8%.Based on the experimental results,a theoretical model was proposed that considers the detonation location and charge mass,boundary conditions,axial compression ratio and material properties.The theoretical model exhibited good agreement with the experimental results,with prediction errors below 10%for both maximum and residual deflection.The effects of parameters were analyzed,and it indicated that an increase in offset distance results in decreased maximum and residual deflections but an increased support angle,thereby exacerbating damage.Higher axial load ratio,span-depth ratio,and longitudinal reinforcement ratio reduce both deflections and support angle.Additionally,a rapid method to predict the maximum and residual deflection of RC columns under off-central blast loading was also proposed based on the Generalized Regression Neural Network(GRNN).Eleven features which related to the RC column properties and the blast characteristics were used in the training process of GRNN,and accurate predictions were achieved with prediction errors within 20%.This study fills the gap in predicting the dynamic response of RC columns under off-central explosion,providing valuable references for blast-resistant design.
基金supported by the National Key Research and Development Program of China under Grant 2022YFB3608300in part by the National Nature Science Foundation of China(NSFC)under Grants 62404050,U2341218,62574056,62204052。
文摘Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal scale tasks.In this study,we report an OECT-based neuromorphic device with tunable relaxation time(τ)by introducing an additional vertical back-gate electrode into a planar structure.The dual-gate design enablesτreconfiguration from 93 to 541 ms.The tunable relaxation behaviors can be attributed to the combined effects of planar-gate induced electrochemical doping and back-gateinduced electrostatic coupling,as verified by electrochemical impedance spectroscopy analysis.Furthermore,we used theτ-tunable OECT devices as physical reservoirs in the RC system for intelligent driving trajectory prediction,achieving a significant improvement in prediction accuracy from below 69%to 99%.The results demonstrate that theτ-tunable OECT shows a promising candidate for multi-temporal scale neuromorphic computing applications.
