The rapid advancement of machine learning based tight-binding Hamiltonian(MLTB)methods has opened new avenues for efficient and accurate electronic structure simulations,particularly in large-scale systems and long-ti...The rapid advancement of machine learning based tight-binding Hamiltonian(MLTB)methods has opened new avenues for efficient and accurate electronic structure simulations,particularly in large-scale systems and long-time scenarios.This review begins with a concise overview of traditional tight-binding(TB)models,including both(semi-)empirical and first-principles approaches,establishing the foundation for understanding MLTB developments.We then present a systematic classification of existing MLTB methodologies,grouped into two major categories:direct prediction of TB Hamiltonian elements and inference of empirical parameters.A comparative analysis with other ML-based electronic structure models is also provided,highlighting the advancement of MLTB approaches.Finally,we explore the emerging MLTB application ecosystem,highlighting how the integration of MLTB models with a diverse suite of post-processing tools from linear-scaling solvers to quantum transport frameworks and molecular dynamics interfaces is essential for tackling complex scientific problems across different domains.The continued advancement of this integrated paradigm promises to accelerate materials discovery and open new frontiers in the predictive simulation of complex quantum phenomena.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
This study develops a surrogate super-resolution(SR)framework that accelerates finite element method(FEM)-based computational fluid dynamics(CFD)using deep learning.High-resolution(HR)FEM-based CFDremains computationa...This study develops a surrogate super-resolution(SR)framework that accelerates finite element method(FEM)-based computational fluid dynamics(CFD)using deep learning.High-resolution(HR)FEM-based CFDremains computationally prohibitive for time-sensitive applications,including patient-specific aneurysm hemodynamics where rapid turnaround is valuable.The proposed pipeline learns to reconstruct HR velocity-magnitude fields fromlow-resolution(LR)FEM solutions generated under the same governing equations and boundary conditions.It consistsof three modules:(i)offline pre-training of a residual network on representative vascular geometries;(ii)lightweightfine-tuning to adapt the pretrained model to geometric variability,including patient-specific aneurysm morphologies;and(iii)an unstructured-to-structured sampling strategy with region-of-interest upsampling that concentrates resolution in flow-critical zones(e.g.,the aneurysm sac)rather than the full domain.This targeted reconstruction substantiallyreduces inference and post-processing cost while preserving key HR flow features.Experiments on cerebral aneurysmmodels show that HR velocity-magnitude fields can be recovered with accuracy comparable to direct HR simulationsat less than 1%of the direct HR simulation cost per analysis(LR simulation and SR inference),while adaptation to newgeometries requires only lightweight fine-tuning with limited target-specific HR data.While clinical endpoints andadditional variables(e.g.,pressure or wall-based metrics)are left for future work,the results indicate that the proposedsurrogate SR approach can streamline FEM-based CFD workflows toward near real-time hemodynamic analysis acrossmorphologically similar vascular models.展开更多
Urban Heat Island(UHI)effects are exacerbated by the expansion of impervious surfaces and loss of vegetation in urban centers,leading to elevated air and surface temperatures and reduced thermal comfort.Urban trees,th...Urban Heat Island(UHI)effects are exacerbated by the expansion of impervious surfaces and loss of vegetation in urban centers,leading to elevated air and surface temperatures and reduced thermal comfort.Urban trees,through shading and evapotranspiration,are among the most effective Nature-based Solutions(NbS)for passive cooling.This study assesses the cooling potential of selected tree species by analyzing their morphological and physiological traits using a combination of ENVI-met microclimate simulations and multiple regression modeling.A total of 15 urban tree species were selected from the literature and analyzed based on their dependency of their cooling efficacy.Later validated in urban setting by Envi-met simulations.Key traits,such as Leaf Area Index(LAI),canopy density,transpiration rate,tree height,rooting depth,and water availability,were analyzed.Multiple linear regression analysis was conducted to quantify the contribution of each trait to ambient temperature reduction.Results revealed that LAI(R^(2)=0.76,p<0.001)and transpiration rate(R^(2)=0.71,p<0.001)were the most significant predictors of daytime cooling,while canopy openness and tree height were more strongly correlated with nighttime heat dissipation.High-performing species,such as Ficus benghalensis,Azadirachta indica,and Samanea saman,demonstrated a maximum temperature reduction of 2.5-4.2℃,especially in compact,low-rise,and mid-rise zones.The study provides a quantitative trait-based framework for tree selection in urban greening initiatives and offers evidence to guide landscape planning and UHI mitigation strategies through scientifically informed plantation design.展开更多
As a representative insensitive high explosive,3-nitro-1,2,4-triazol-5-one(NTO)has garnered significant attention due to its ability to substantially reduce the risk of accidental detonation in munitions.However,its i...As a representative insensitive high explosive,3-nitro-1,2,4-triazol-5-one(NTO)has garnered significant attention due to its ability to substantially reduce the risk of accidental detonation in munitions.However,its inherent acidity induces severe interfacial corrosion of metal casings,thereby limiting its engineering applications.Based on the micro-corrosion mechanism of NTO on carbon steel(CS),this study designs an arginine-derived corrosion inhibitor,N2-[(phenylamino)thioxomethyl]-arginine(PTA).Electrochemical tests reveal that PTA exhibits an outstanding corrosion inhibition efficiency of 98.0%in NTO solution.Density functional theory(DFT)and molecular dynamics(MD)simulations elucidate the inhibition mechanism of PTA,demonstrating that it not only co-adsorbs with NTO^(−) onto the CS surface to form a dense and stable protective film but also disrupts the strong interactions between NTO^(−) and Fe,thereby suppressing nitro group-induced reduction,decomposition,and excessive surface oxidation.Furthermore,a PTA-loaded mesoporous silica(mSiO_(2))nanoparticles(NPs)-reinforced epoxy resin(EP)composite coating was constructed.Benefiting from the enhanced barrier properties of PTA@mSiO_(2) NPs and the synergistic effect between PTA and NTO^(−),the low-frequency impedance of the composite coating remained as high as 1.29×10^(9)Ω·cm^(2) after 30 days of immersion in NTO solution,exhibiting a two-order-of-magnitude improvement compared to the pure EP coating.This study proposes an effective corrosion control strategy to mitigate NTO-induced corrosion,providing insights into the development of advanced corrosion protection strategies for broader applications.展开更多
Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions and has become a growing focus of research and deployment.This paper presents numerical simulations of CO_(2) injection and stora...Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions and has become a growing focus of research and deployment.This paper presents numerical simulations of CO_(2) injection and storage in a depleted gas reservoir within the B Depression and evaluates associated CO_(2) trapping mechanisms.In the base case,a constant injection rate of 3500 m^(3)/d over fifteen years resulted in a cumulative injection of 19.2×10^(6) m^(3).The CO_(2) plume expanded radially during injection and subsequently migrated up-dip under buoyancy forces.The final stored mass of CO_(2) in the reservoir was 10.6 million tonnes(Mt),representing less than 10% of its theoretical capacity.The plume was projected to reach the entrapment crest and the top of the reservoir within a century,indicating secure long-term containment.Structural,stratigraphic,and residual trapping dominate in Reservoir A(approximately 90%).Anticlinal closures with thick overlying mudstones in the Zhujiang Formation provide effective seals,further enhancing storage security.Reservoir properties and heterogeneity play a crucial role in controlling CO_(2) storage.However,reservoir heterogeneity exerts only a limited influence when intrinsic properties are favorable.Overall,the study and implementation of CO_(2) capture,utilization,and storage(CCUS)in China's offshore basins show promising prospects.展开更多
Compared to the well-studied two-dimensional(2D)ferroelectricity,the appearance of 2D antiferroelectricity is much rarer,where local dipoles from the nonequivalent sublattices within 2D monolayers are oppositely orien...Compared to the well-studied two-dimensional(2D)ferroelectricity,the appearance of 2D antiferroelectricity is much rarer,where local dipoles from the nonequivalent sublattices within 2D monolayers are oppositely oriented.Using NbOCl_(2) monolayer with competing ferroelectric(FE)and antiferroelectric(AFE)phases as a 2D material platform,we demonstrate the emergence of intrinsic antiferroelectricity in NbOCl_(2) monolayer under experimentally accessible shear strain,along with new functionality associated with electric field-induced AFE-to-FE phase transition.Specifically,the complex configuration space accommodating FE and AFE phases,polarization switching kinetics,and finite temperature thermodynamic properties of 2D NbOCl_(2) are all accurately predicted by large-scale molecular dynamics simulations based on deep learning interatomic potential model.Moreover,room temperature stable antiferroelectricity with low polarization switching barrier and one-dimensional collinear polarization arrangement is predicted in shear-deformed NbOCl_(2) monolayer.The transition from AFE to FE phase in 2D NbOCl_(2) can be triggered by a low critical electric field,leading to a double polarization–electric(P–E)loop with small hysteresis.A new type of optoelectronic device composed of AFE-NbOCl_(2) is proposed,enabling electric“writing”and nonlinear optical“reading”logical operation with fast operation speed and low power consumption.展开更多
Deeply buried mountain tunnels are often exposed to the risk of rock bursts,which always cause serious damage to the supporting structures and threaten the safety of the engineers.Due to the limited data available,a s...Deeply buried mountain tunnels are often exposed to the risk of rock bursts,which always cause serious damage to the supporting structures and threaten the safety of the engineers.Due to the limited data available,a suitable approach to predict the rockburst tendency at the preliminary stage becomes very important.In this study,an integrated methodology combining 3D initial stress inversion and rockburst tendency prediction was developed and subsequently applied to a case study of the Sangzhuling Tunnel on the Sichuan–Tibet Railway.The numerical modelling involved inverting the initial stress field using a multiple linear regression method.The tunnel excavation was simulated separately by FDM and DEM,based on a stress boundary condition from the inverted stress field.The comparative analysis demonstrates that the rockburst ratio calculated using DEM(76.70%)exhibits a slight increase compared to FDM(75.38%),and the rockburst location is consistent with the actual situation.This suggests that DEM is more suitable for simulating the stress redistribution during excavation in a jointed rock mass.The numerical simulation combined with the deviatoric stress approach effectively predicts rockburst tendency,meeting the engineering requirements.Despite its limitations,numerical simulation remains a reliable method for predicting rock bursts.展开更多
The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the ...The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the factors controlling their development remain subjects of debate.This paper,based on seismic profile analysis,employs physical simulation experiments to establish a'wedge'type subduction model.The study explores the influence of the initial wedge angle,horizontal sand layer thickness,and the presence or absence of a decollement layer on the structural styles of the thrust wedge.Experimental results indicate that as the initial wedge angle decreases from 11°to 8°,the lateral growth of the thrust wedge increases,whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm,the spacing between the frontal thrusts decreases and the number of thrust faults increases.Both lateral and vertical growth are relatively reduced,resulting in a smaller thrust wedge.When a decollement layer is present,the structural style exhibits layered deformation.The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts.In conclusion,the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.展开更多
Eutectic high entropy alloys are noted for their excellent castability and comprehensive mechanical properties.The excellent mechanical properties are closely related to the activation and evolution of deformation mec...Eutectic high entropy alloys are noted for their excellent castability and comprehensive mechanical properties.The excellent mechanical properties are closely related to the activation and evolution of deformation mechanisms at the atomic scale.In this work,AlCoCrFeNi2.1 alloy is taken as the research object.The mechanical behaviors and deformation mechanisms of the FCC and B2 single crystals with different orientations and the FCC/B2 composites with K-S orientation relationship during nanoindentation processes are systematically studied by molecular dynamics simulations.The results show that the mechanical behaviors of FCC single crystals are significantly orientation-dependent,meanwhile,the indentation force of[110]single crystal is the lowest at the elastic-plastic transition point,and that for[100]single crystal is the lowest in plastic deformation stage.Compared with FCC,the stress for B2 single crystals at the elastic-plastic transition point is higher.However,more deformation systems such as stacking faults,twins and dislocation loops are activated in FCC single crystal during the plastic deformation process,resulting in higher indentation force.For composites,the flow stress increases with the increase of B2 phase thickness during the initial stage of deformation.When indenter penetrates heterogeneous interface,the significantly increased deformation system in FCC phase leads to a significant increase in indentation force.The mechanical behaviors and deformation mechanisms depend on the component single crystal.When the thickness of the component layer is less than 15 nm,the heterogeneous interfaces fail to prevent the dislocation slip and improve the indentation force.The results will enrich the plastic deformation mechanisms of multi-principal eutectic alloys and provide guidance for the design of nanocrystalline metallic materials.展开更多
The strategic dispersion of carbon nanotubes(CNTs)within triblock copolymer matrix is key to fabricating nanocomposites with the desired electrical properties.This study investigated the self-assembly and electrical b...The strategic dispersion of carbon nanotubes(CNTs)within triblock copolymer matrix is key to fabricating nanocomposites with the desired electrical properties.This study investigated the self-assembly and electrical behavior of a polystyrene-polybutadiene-polystyrene(SBS)matrix with CNTs of different aspect ratios using hybrid particle-field molecular dynamics simulations.Structural factor analysis of the nanocomposites indicated that CNTs with higher aspect ratios promoted the transition of the SBS matrix from a bicontinuous to a lamellar phase.The resistor network algorithm method showed that the electrical conductivity of SBS and CNTs nanocomposites was influenced by the interplay between the CNTs aspect ratios,concentrations,and domain sizes of the triblock copolymer SBS.Our research sheds light on the relationship between CNTs dispersion and the electrical behavior of SBS/CNTs nanocomposites,guiding the engineering of materials to achieve desired electrical properties through the modulation of CNTs aspect ratios and tailored sizing of triblock copolymer domains.展开更多
To address the limitations of existing coupling methods in aero-engine system simulation,which fail to adaptively adjust iterative parameters and coupling relationships,which can result in low efficiency and in⁃stabil...To address the limitations of existing coupling methods in aero-engine system simulation,which fail to adaptively adjust iterative parameters and coupling relationships,which can result in low efficiency and in⁃stability,this study introduces a‘Dynamic Event-Driven Co-Simulation’algorithm integrated with decision tree algorithms.This algorithm separates the overall coupling relationships and the main solver from the primary mod⁃el,utilizing a dynamic event monitoring module to adaptively adjust simulation strategies,including iteration pa⁃rameters,coupling relationships,and convergence criteria.This facilitates efficient adaptive simulations of dy⁃namic events while balancing solution accuracy and computational efficiency.The research focuses on a twinshaft turbofan engine,establishing six system-level models that encompass overall performance and various sub⁃systems based on three coupling methods,along with a multidisciplinary multi-fidelity simulation framework in⁃corporating a 3D CFD nozzle model.The study tests both model exchange and coupled simulation methods under a 14 s transient acceleration and deceleration scenario.In a 100%throttle condition,a high-fidelity nozzle model is used to analyze the sensitivity of different convergence criteria on computational efficiency and accuracy.Re⁃sults indicate that the accuracy and efficiency achieved with this method are comparable to those of PROOSIS soft⁃ware(18 s and 35 s,respectively),while being 71%more efficient than Simulink software(62 s and 120 s,re⁃spectively).Furthermore,appropriately relaxing the convergence criteria for the 0D model(from 10-6 to 10-4)while enhancing those for the 3D model(from 3000 steps to 6000 steps)can effectively balance computational accuracy and efficiency.展开更多
Self-assembly of block copolymers(BCPs)is highly intricate and is adsorbing extensive experimental and simulation efforts to reveal it for maximizing structural order and device performances.The coarse-grained(CG)mole...Self-assembly of block copolymers(BCPs)is highly intricate and is adsorbing extensive experimental and simulation efforts to reveal it for maximizing structural order and device performances.The coarse-grained(CG)molecular dynamics(MD)simulation offers a microscopic angle to view the self-assembly of BCPs.Although some molecular details are sacrificed during CG processes,this method exhibits remarkable computational efficiency.In this study,a comprehensive CG model for polystyrene-block-poly(2-vinylpyridine),PS-b-P2VP,one of the most extensively studied BCPs for its high Flory-Huggins interaction parameter,is constructed,with parameters optimized using target values derived from all-atom MD simulations.The CG model precisely coincides with various classical self-assembling morphologies observed in experimental studies,matching the theoretical phase diagrams.Moreover,the conformational asymmetry of the experimental phase diagram is also clearly revealed by our simulation results,and the phase boundaries obtained from simulations are highly consistent with experimental results.The CG model is expected to extend to simulate the self-assembly behaviors of other BCPs in addition to PS-b-P2VP,thus increasing understanding of the microphase separation of BCPs from the molecular level.展开更多
UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechani...UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.展开更多
The multi-scale modeling combined with the cohesive zone model(CZM)and the molecular dynamics(MD)method were preformed to simulate the crack propagation in NiTi shape memory alloys(SMAs).The metallographic microscope ...The multi-scale modeling combined with the cohesive zone model(CZM)and the molecular dynamics(MD)method were preformed to simulate the crack propagation in NiTi shape memory alloys(SMAs).The metallographic microscope and image processing technology were employed to achieve a quantitative grain size distribution of NiTi alloys so as to provide experimental data for molecular dynamics modeling at the atomic scale.Considering the size effect of molecular dynamics model on material properties,a reasonable modeling size was provided by taking into account three characteristic dimensions from the perspective of macro,meso,and micro scales according to the Buckinghamπtheorem.Then,the corresponding MD simulation on deformation and fracture behavior was investigated to derive a parameterized traction-separation(T-S)law,and then it was embedded into cohesive elements of finite element software.Thus,the crack propagation behavior in NiTi alloys was reproduced by the finite element method(FEM).The experimental results show that the predicted initiation fracture toughness is in good agreement with experimental data.In addition,it is found that the dynamics initiation fracture toughness increases with decreasing grain size and increasing loading velocity.展开更多
Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and t...Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.展开更多
Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies ...Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies between 1 keV and 150 keV.The results indicate that a smaller grain size leads to more defects forming in grain boundary regions during cascade processes.The impact of high-energy PKA may cause a certain degree of distortion of the grain boundaries,which has a higher probability in systems with smaller grain sizes and becomes more pronounced as the PKA energy increases.The direction of PKA can affect the formation and diffusion pathways of defects.When the PKA direction is perpendicular to the grain boundary,defects preferentially form near the grain boundary regions;by contrast,defects are more inclined to form in the interior of the grains.These results are of great significance for comprehending the changes in the performance of polycrystalline W under the high-energy fusion environments and can provide theoretical guidance for further optimization and application of W-based plasma materials.展开更多
Explorations into new electrolytes have highlighted the critical impact of solvation structure on battery performance,Classical molecular dynamics(CMD)using semi-empirical force fields has become an essential tool for...Explorations into new electrolytes have highlighted the critical impact of solvation structure on battery performance,Classical molecular dynamics(CMD)using semi-empirical force fields has become an essential tool for simulating solvation structures.However,mainstream force fields often lack accuracy in describing strong ion-solvent interactions,causing disparities between CMD simulations and experimental observations.Although some empirical methods have been employed in some of the studies to address this issue,their effectiveness has been limited.Our CMD research,supported by quantum chemical calculations and experimental data,reveals that the solvation structure is influenced not only by the charge model but also by the polarization description.Previous empirical approaches that focused solely on adjusting ion-solvent interaction strengths overlooked the importance of polarization effects.Building on this insight,we propose integrating the Drude polarization model into mainstream force fields and verify its feasibility in carbonate,ether,and nitrile electrolytes.Our experimental results demonstrate that this approach significantly enhances the accuracy of CMD-simulated solvation structures.This work is expected to provide a more reliable CMD method for electrolyte design,shielding researchers from the pitfalls of erroneous simulation outcomes.展开更多
基金supported by the Advanced Materials-National Science and Technology Major Project(Grant No.2025ZD0618401)the National Natural Science Foundation of China(Grant No.12504285)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20250472)NFSG grant from BITS-Pilani,Dubai campus。
文摘The rapid advancement of machine learning based tight-binding Hamiltonian(MLTB)methods has opened new avenues for efficient and accurate electronic structure simulations,particularly in large-scale systems and long-time scenarios.This review begins with a concise overview of traditional tight-binding(TB)models,including both(semi-)empirical and first-principles approaches,establishing the foundation for understanding MLTB developments.We then present a systematic classification of existing MLTB methodologies,grouped into two major categories:direct prediction of TB Hamiltonian elements and inference of empirical parameters.A comparative analysis with other ML-based electronic structure models is also provided,highlighting the advancement of MLTB approaches.Finally,we explore the emerging MLTB application ecosystem,highlighting how the integration of MLTB models with a diverse suite of post-processing tools from linear-scaling solvers to quantum transport frameworks and molecular dynamics interfaces is essential for tackling complex scientific problems across different domains.The continued advancement of this integrated paradigm promises to accelerate materials discovery and open new frontiers in the predictive simulation of complex quantum phenomena.
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This study develops a surrogate super-resolution(SR)framework that accelerates finite element method(FEM)-based computational fluid dynamics(CFD)using deep learning.High-resolution(HR)FEM-based CFDremains computationally prohibitive for time-sensitive applications,including patient-specific aneurysm hemodynamics where rapid turnaround is valuable.The proposed pipeline learns to reconstruct HR velocity-magnitude fields fromlow-resolution(LR)FEM solutions generated under the same governing equations and boundary conditions.It consistsof three modules:(i)offline pre-training of a residual network on representative vascular geometries;(ii)lightweightfine-tuning to adapt the pretrained model to geometric variability,including patient-specific aneurysm morphologies;and(iii)an unstructured-to-structured sampling strategy with region-of-interest upsampling that concentrates resolution in flow-critical zones(e.g.,the aneurysm sac)rather than the full domain.This targeted reconstruction substantiallyreduces inference and post-processing cost while preserving key HR flow features.Experiments on cerebral aneurysmmodels show that HR velocity-magnitude fields can be recovered with accuracy comparable to direct HR simulationsat less than 1%of the direct HR simulation cost per analysis(LR simulation and SR inference),while adaptation to newgeometries requires only lightweight fine-tuning with limited target-specific HR data.While clinical endpoints andadditional variables(e.g.,pressure or wall-based metrics)are left for future work,the results indicate that the proposedsurrogate SR approach can streamline FEM-based CFD workflows toward near real-time hemodynamic analysis acrossmorphologically similar vascular models.
文摘Urban Heat Island(UHI)effects are exacerbated by the expansion of impervious surfaces and loss of vegetation in urban centers,leading to elevated air and surface temperatures and reduced thermal comfort.Urban trees,through shading and evapotranspiration,are among the most effective Nature-based Solutions(NbS)for passive cooling.This study assesses the cooling potential of selected tree species by analyzing their morphological and physiological traits using a combination of ENVI-met microclimate simulations and multiple regression modeling.A total of 15 urban tree species were selected from the literature and analyzed based on their dependency of their cooling efficacy.Later validated in urban setting by Envi-met simulations.Key traits,such as Leaf Area Index(LAI),canopy density,transpiration rate,tree height,rooting depth,and water availability,were analyzed.Multiple linear regression analysis was conducted to quantify the contribution of each trait to ambient temperature reduction.Results revealed that LAI(R^(2)=0.76,p<0.001)and transpiration rate(R^(2)=0.71,p<0.001)were the most significant predictors of daytime cooling,while canopy openness and tree height were more strongly correlated with nighttime heat dissipation.High-performing species,such as Ficus benghalensis,Azadirachta indica,and Samanea saman,demonstrated a maximum temperature reduction of 2.5-4.2℃,especially in compact,low-rise,and mid-rise zones.The study provides a quantitative trait-based framework for tree selection in urban greening initiatives and offers evidence to guide landscape planning and UHI mitigation strategies through scientifically informed plantation design.
文摘As a representative insensitive high explosive,3-nitro-1,2,4-triazol-5-one(NTO)has garnered significant attention due to its ability to substantially reduce the risk of accidental detonation in munitions.However,its inherent acidity induces severe interfacial corrosion of metal casings,thereby limiting its engineering applications.Based on the micro-corrosion mechanism of NTO on carbon steel(CS),this study designs an arginine-derived corrosion inhibitor,N2-[(phenylamino)thioxomethyl]-arginine(PTA).Electrochemical tests reveal that PTA exhibits an outstanding corrosion inhibition efficiency of 98.0%in NTO solution.Density functional theory(DFT)and molecular dynamics(MD)simulations elucidate the inhibition mechanism of PTA,demonstrating that it not only co-adsorbs with NTO^(−) onto the CS surface to form a dense and stable protective film but also disrupts the strong interactions between NTO^(−) and Fe,thereby suppressing nitro group-induced reduction,decomposition,and excessive surface oxidation.Furthermore,a PTA-loaded mesoporous silica(mSiO_(2))nanoparticles(NPs)-reinforced epoxy resin(EP)composite coating was constructed.Benefiting from the enhanced barrier properties of PTA@mSiO_(2) NPs and the synergistic effect between PTA and NTO^(−),the low-frequency impedance of the composite coating remained as high as 1.29×10^(9)Ω·cm^(2) after 30 days of immersion in NTO solution,exhibiting a two-order-of-magnitude improvement compared to the pure EP coating.This study proposes an effective corrosion control strategy to mitigate NTO-induced corrosion,providing insights into the development of advanced corrosion protection strategies for broader applications.
基金funded by the National Natural Science Foundation of China(Grant No.42102169)the Shaanxi Province key Research and Development Project(Grant No.2023-ZDLSF-64)+1 种基金the Scientific Research and Technological Development Project of China National Logging Corporation(Grant No.25ZYCJSG013-2504)the Youth Science and Technology Special Fund of PetroChina(Grant No.2024DQ03172)。
文摘Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions and has become a growing focus of research and deployment.This paper presents numerical simulations of CO_(2) injection and storage in a depleted gas reservoir within the B Depression and evaluates associated CO_(2) trapping mechanisms.In the base case,a constant injection rate of 3500 m^(3)/d over fifteen years resulted in a cumulative injection of 19.2×10^(6) m^(3).The CO_(2) plume expanded radially during injection and subsequently migrated up-dip under buoyancy forces.The final stored mass of CO_(2) in the reservoir was 10.6 million tonnes(Mt),representing less than 10% of its theoretical capacity.The plume was projected to reach the entrapment crest and the top of the reservoir within a century,indicating secure long-term containment.Structural,stratigraphic,and residual trapping dominate in Reservoir A(approximately 90%).Anticlinal closures with thick overlying mudstones in the Zhujiang Formation provide effective seals,further enhancing storage security.Reservoir properties and heterogeneity play a crucial role in controlling CO_(2) storage.However,reservoir heterogeneity exerts only a limited influence when intrinsic properties are favorable.Overall,the study and implementation of CO_(2) capture,utilization,and storage(CCUS)in China's offshore basins show promising prospects.
基金supported by the National Natural Science Foundation of China (Grant No.11574244 for G.Y.G.)the XJTU Research Fund for AI Science (Grant No.2025YXYC011 for G.Y.G.)the Hong Kong Global STEM Professorship Scheme (for X.C.Z.)。
文摘Compared to the well-studied two-dimensional(2D)ferroelectricity,the appearance of 2D antiferroelectricity is much rarer,where local dipoles from the nonequivalent sublattices within 2D monolayers are oppositely oriented.Using NbOCl_(2) monolayer with competing ferroelectric(FE)and antiferroelectric(AFE)phases as a 2D material platform,we demonstrate the emergence of intrinsic antiferroelectricity in NbOCl_(2) monolayer under experimentally accessible shear strain,along with new functionality associated with electric field-induced AFE-to-FE phase transition.Specifically,the complex configuration space accommodating FE and AFE phases,polarization switching kinetics,and finite temperature thermodynamic properties of 2D NbOCl_(2) are all accurately predicted by large-scale molecular dynamics simulations based on deep learning interatomic potential model.Moreover,room temperature stable antiferroelectricity with low polarization switching barrier and one-dimensional collinear polarization arrangement is predicted in shear-deformed NbOCl_(2) monolayer.The transition from AFE to FE phase in 2D NbOCl_(2) can be triggered by a low critical electric field,leading to a double polarization–electric(P–E)loop with small hysteresis.A new type of optoelectronic device composed of AFE-NbOCl_(2) is proposed,enabling electric“writing”and nonlinear optical“reading”logical operation with fast operation speed and low power consumption.
基金financially supported by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(Grant No.SKLGP2020Z007)。
文摘Deeply buried mountain tunnels are often exposed to the risk of rock bursts,which always cause serious damage to the supporting structures and threaten the safety of the engineers.Due to the limited data available,a suitable approach to predict the rockburst tendency at the preliminary stage becomes very important.In this study,an integrated methodology combining 3D initial stress inversion and rockburst tendency prediction was developed and subsequently applied to a case study of the Sangzhuling Tunnel on the Sichuan–Tibet Railway.The numerical modelling involved inverting the initial stress field using a multiple linear regression method.The tunnel excavation was simulated separately by FDM and DEM,based on a stress boundary condition from the inverted stress field.The comparative analysis demonstrates that the rockburst ratio calculated using DEM(76.70%)exhibits a slight increase compared to FDM(75.38%),and the rockburst location is consistent with the actual situation.This suggests that DEM is more suitable for simulating the stress redistribution during excavation in a jointed rock mass.The numerical simulation combined with the deviatoric stress approach effectively predicts rockburst tendency,meeting the engineering requirements.Despite its limitations,numerical simulation remains a reliable method for predicting rock bursts.
基金the National Natural Science Foundation of China(No.42076069)。
文摘The frontal edge of the Makran accretionary wedge is characterized by the development of multiple imbricate thrust faults trending E-W and relatively parallel.However,the mechanisms underlying their formation and the factors controlling their development remain subjects of debate.This paper,based on seismic profile analysis,employs physical simulation experiments to establish a'wedge'type subduction model.The study explores the influence of the initial wedge angle,horizontal sand layer thickness,and the presence or absence of a decollement layer on the structural styles of the thrust wedge.Experimental results indicate that as the initial wedge angle decreases from 11°to 8°,the lateral growth of the thrust wedge increases,whereas vertical growth diminishes.When the horizontal sand layer thickness is reduced from 4.5 cm to 3.0 cm,the spacing between the frontal thrusts decreases and the number of thrust faults increases.Both lateral and vertical growth are relatively reduced,resulting in a smaller thrust wedge.When a decollement layer is present,the structural style exhibits layered deformation.The decollement layer constrains the development of back thrusts and promotes the localized formation of frontal thrusts.In conclusion,the imbricate thrust faults at the frontal edge of the Makran accretionary wedge are primarily controlled by the characteristics of the wedge itself and the presence of the decollement layer.
基金supported by the Natural Science Foundation of Hebei Province(E2024209052)the Youth Scholars Promotion Plan of North China University of Science and Technology(QNTJ202307).
文摘Eutectic high entropy alloys are noted for their excellent castability and comprehensive mechanical properties.The excellent mechanical properties are closely related to the activation and evolution of deformation mechanisms at the atomic scale.In this work,AlCoCrFeNi2.1 alloy is taken as the research object.The mechanical behaviors and deformation mechanisms of the FCC and B2 single crystals with different orientations and the FCC/B2 composites with K-S orientation relationship during nanoindentation processes are systematically studied by molecular dynamics simulations.The results show that the mechanical behaviors of FCC single crystals are significantly orientation-dependent,meanwhile,the indentation force of[110]single crystal is the lowest at the elastic-plastic transition point,and that for[100]single crystal is the lowest in plastic deformation stage.Compared with FCC,the stress for B2 single crystals at the elastic-plastic transition point is higher.However,more deformation systems such as stacking faults,twins and dislocation loops are activated in FCC single crystal during the plastic deformation process,resulting in higher indentation force.For composites,the flow stress increases with the increase of B2 phase thickness during the initial stage of deformation.When indenter penetrates heterogeneous interface,the significantly increased deformation system in FCC phase leads to a significant increase in indentation force.The mechanical behaviors and deformation mechanisms depend on the component single crystal.When the thickness of the component layer is less than 15 nm,the heterogeneous interfaces fail to prevent the dislocation slip and improve the indentation force.The results will enrich the plastic deformation mechanisms of multi-principal eutectic alloys and provide guidance for the design of nanocrystalline metallic materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52273019,62173065,22133002,22273031,and 12274056)Fundamental Research Funds for the Central Universities(No.04442024074)+2 种基金NationalKey R&D Program of China(No.2022YFB3707300)Beijing Natural Science Foundation(No.4242040)Scientific Research Funds Project of Liaoning Provincial Department of Education(No.LJKZ0034)。
文摘The strategic dispersion of carbon nanotubes(CNTs)within triblock copolymer matrix is key to fabricating nanocomposites with the desired electrical properties.This study investigated the self-assembly and electrical behavior of a polystyrene-polybutadiene-polystyrene(SBS)matrix with CNTs of different aspect ratios using hybrid particle-field molecular dynamics simulations.Structural factor analysis of the nanocomposites indicated that CNTs with higher aspect ratios promoted the transition of the SBS matrix from a bicontinuous to a lamellar phase.The resistor network algorithm method showed that the electrical conductivity of SBS and CNTs nanocomposites was influenced by the interplay between the CNTs aspect ratios,concentrations,and domain sizes of the triblock copolymer SBS.Our research sheds light on the relationship between CNTs dispersion and the electrical behavior of SBS/CNTs nanocomposites,guiding the engineering of materials to achieve desired electrical properties through the modulation of CNTs aspect ratios and tailored sizing of triblock copolymer domains.
文摘To address the limitations of existing coupling methods in aero-engine system simulation,which fail to adaptively adjust iterative parameters and coupling relationships,which can result in low efficiency and in⁃stability,this study introduces a‘Dynamic Event-Driven Co-Simulation’algorithm integrated with decision tree algorithms.This algorithm separates the overall coupling relationships and the main solver from the primary mod⁃el,utilizing a dynamic event monitoring module to adaptively adjust simulation strategies,including iteration pa⁃rameters,coupling relationships,and convergence criteria.This facilitates efficient adaptive simulations of dy⁃namic events while balancing solution accuracy and computational efficiency.The research focuses on a twinshaft turbofan engine,establishing six system-level models that encompass overall performance and various sub⁃systems based on three coupling methods,along with a multidisciplinary multi-fidelity simulation framework in⁃corporating a 3D CFD nozzle model.The study tests both model exchange and coupled simulation methods under a 14 s transient acceleration and deceleration scenario.In a 100%throttle condition,a high-fidelity nozzle model is used to analyze the sensitivity of different convergence criteria on computational efficiency and accuracy.Re⁃sults indicate that the accuracy and efficiency achieved with this method are comparable to those of PROOSIS soft⁃ware(18 s and 35 s,respectively),while being 71%more efficient than Simulink software(62 s and 120 s,re⁃spectively).Furthermore,appropriately relaxing the convergence criteria for the 0D model(from 10-6 to 10-4)while enhancing those for the 3D model(from 3000 steps to 6000 steps)can effectively balance computational accuracy and efficiency.
基金supported by the National Natural Science Foundation of China(22438005,22108117).
文摘Self-assembly of block copolymers(BCPs)is highly intricate and is adsorbing extensive experimental and simulation efforts to reveal it for maximizing structural order and device performances.The coarse-grained(CG)molecular dynamics(MD)simulation offers a microscopic angle to view the self-assembly of BCPs.Although some molecular details are sacrificed during CG processes,this method exhibits remarkable computational efficiency.In this study,a comprehensive CG model for polystyrene-block-poly(2-vinylpyridine),PS-b-P2VP,one of the most extensively studied BCPs for its high Flory-Huggins interaction parameter,is constructed,with parameters optimized using target values derived from all-atom MD simulations.The CG model precisely coincides with various classical self-assembling morphologies observed in experimental studies,matching the theoretical phase diagrams.Moreover,the conformational asymmetry of the experimental phase diagram is also clearly revealed by our simulation results,and the phase boundaries obtained from simulations are highly consistent with experimental results.The CG model is expected to extend to simulate the self-assembly behaviors of other BCPs in addition to PS-b-P2VP,thus increasing understanding of the microphase separation of BCPs from the molecular level.
基金financially supported by the National Natural Science Foundation of China(Nos.52303298 and 52233002)。
文摘UHMWPE fibers exhibit impressive modulus and strength,but they have not reached their theoretical limits.Researchers focus on molecular weight,orientation,and crystallinity of UHMWPE,yet their contributions to mechanical properties are unclear.Molecular dynamics simulations are valuable but often limited by computational constraints.Our aim is to simulate higher molecular weights to better represent real UHMWPE fibers.We used Packmol and Polyply methodologies to construct PE systems,with Polyply reproducing more reasonable properties of UHMWPE fibers.Additionally,tensile simulations showed that orientation and crystallinity greatly impact Young's modulus more than molecular weight.Energy decomposition indicated that higher molecular weights lead to covalent bonds that can withstand more energy during stretching,thus increasing breaking strength.Combining simulations with machine learning,we found that orientation has the most significant impact on Young's modulus,contributing 60%,and molecular weight plays the most crucial role in determining the breaking strength,accounting for 65%.This study provides a theoretical basis and guidelines for enhancing UHMWPE's modulus and strength.
基金Funded by the National Natural Science Foundation of China Academy of Engineering Physics and Jointly Setup"NSAF"Joint Fund(No.U1430119)。
文摘The multi-scale modeling combined with the cohesive zone model(CZM)and the molecular dynamics(MD)method were preformed to simulate the crack propagation in NiTi shape memory alloys(SMAs).The metallographic microscope and image processing technology were employed to achieve a quantitative grain size distribution of NiTi alloys so as to provide experimental data for molecular dynamics modeling at the atomic scale.Considering the size effect of molecular dynamics model on material properties,a reasonable modeling size was provided by taking into account three characteristic dimensions from the perspective of macro,meso,and micro scales according to the Buckinghamπtheorem.Then,the corresponding MD simulation on deformation and fracture behavior was investigated to derive a parameterized traction-separation(T-S)law,and then it was embedded into cohesive elements of finite element software.Thus,the crack propagation behavior in NiTi alloys was reproduced by the finite element method(FEM).The experimental results show that the predicted initiation fracture toughness is in good agreement with experimental data.In addition,it is found that the dynamics initiation fracture toughness increases with decreasing grain size and increasing loading velocity.
基金supported by the Science Fund for the Gansu Provincial Natural Science Foundation Project(22JR5RA339).
文摘Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.
基金Project supported by the National MCF Energy Research and Development Program of China(Grant No.2018YFE0308101)the National Key Research and Development Program of China(Grant No.2018YFB0704000)+1 种基金the Suqian Science and Technology Program(Grant No.K202337)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.23KJD490001).
文摘Using molecular dynamics methods,simulations of collision cascades in polycrystalline tungsten(W)have been conducted in this study,including different primary-knock-on atom(PKA)directions,grain sizes,and PKA energies between 1 keV and 150 keV.The results indicate that a smaller grain size leads to more defects forming in grain boundary regions during cascade processes.The impact of high-energy PKA may cause a certain degree of distortion of the grain boundaries,which has a higher probability in systems with smaller grain sizes and becomes more pronounced as the PKA energy increases.The direction of PKA can affect the formation and diffusion pathways of defects.When the PKA direction is perpendicular to the grain boundary,defects preferentially form near the grain boundary regions;by contrast,defects are more inclined to form in the interior of the grains.These results are of great significance for comprehending the changes in the performance of polycrystalline W under the high-energy fusion environments and can provide theoretical guidance for further optimization and application of W-based plasma materials.
基金supported by the Science and Technology Project of State Grid Corporation of China(5419-202199552A-0-5-ZN).
文摘Explorations into new electrolytes have highlighted the critical impact of solvation structure on battery performance,Classical molecular dynamics(CMD)using semi-empirical force fields has become an essential tool for simulating solvation structures.However,mainstream force fields often lack accuracy in describing strong ion-solvent interactions,causing disparities between CMD simulations and experimental observations.Although some empirical methods have been employed in some of the studies to address this issue,their effectiveness has been limited.Our CMD research,supported by quantum chemical calculations and experimental data,reveals that the solvation structure is influenced not only by the charge model but also by the polarization description.Previous empirical approaches that focused solely on adjusting ion-solvent interaction strengths overlooked the importance of polarization effects.Building on this insight,we propose integrating the Drude polarization model into mainstream force fields and verify its feasibility in carbonate,ether,and nitrile electrolytes.Our experimental results demonstrate that this approach significantly enhances the accuracy of CMD-simulated solvation structures.This work is expected to provide a more reliable CMD method for electrolyte design,shielding researchers from the pitfalls of erroneous simulation outcomes.
