The ground-based experimental tests are crucial to verify the related technologies of the drag-free satellite.This work presents a design method of the ground simulator testbed for emulating the planar dynamics of the...The ground-based experimental tests are crucial to verify the related technologies of the drag-free satellite.This work presents a design method of the ground simulator testbed for emulating the planar dynamics of the space drag-free systems.In this paper,the planar dynamic characteristics of the drag-free satellite with double test masses are analyzed and nondimensionalized.A simulator vehicle composed of an air bearing testbed and two inverted pendulums is devised on the basic of equivalent mass and equivalent stiffness proposed firstly in this paper.And the dynamic model of the simulator equivalent to the sensitive axis motion of the test mass and the planar motion of the satellite is derived from the Euler-Lagrange method.Then,the dynamic equivalence conditions between the space prototype system and the ground model system are derived from Pi theorem.To satisfy these conditions,the scaling laws of two systems and requirements for the inverted pendulum are put forward.Besides,the corresponding control scaling laws and a closed-loop control strategy are deduced and applied to establishing the numerical simulation experiments of underactuated system.Subsequently,the comparative simulation results demonstrate the similarity of dynamical behavior between the scaled-down ground model and the space prototype.As a result,the rationality and effectiveness of the design method are proved,facilitating the ground simulation of future gravitational wave detection satellites.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
Based on the dynamical characteristic parameters of the real vehicle, the modehng approach ancl procedure of dynamics of vehicles are expatiated. The layout of vehicle dynamics is proposed, and the sub-models of the d...Based on the dynamical characteristic parameters of the real vehicle, the modehng approach ancl procedure of dynamics of vehicles are expatiated. The layout of vehicle dynamics is proposed, and the sub-models of the diesel engine, drivetrain system and vehicle multi-body dynamics are introduced. Finally, the running characteristic data of the virtual and real vehicles are compared, which shows that the dynamics model is similar closely to the real vehicle system.展开更多
Increasing evidence showed that histone deacetylase 6(HDAC6)dysfunction is directly associated with the onset and progression of various diseases,especially cancers,making the development of HDAC6-targeted anti-tumor ...Increasing evidence showed that histone deacetylase 6(HDAC6)dysfunction is directly associated with the onset and progression of various diseases,especially cancers,making the development of HDAC6-targeted anti-tumor agents a research hotspot.In this study,artificial intelligence(AI)technology and molecular simulation strategies were fully integrated to construct an efficient and precise drug screening pipeline,which combined Voting strategy based on compound-protein interaction(CPI)prediction models,cascade molecular docking,and molecular dynamic(MD)simulations.The biological potential of the screened compounds was further evaluated through enzymatic and cellular activity assays.Among the identified compounds,Cmpd.18 exhibited more potent HDAC6 enzyme inhibitory activity(IC_(50)=5.41 nM)than that of tubastatin A(TubA)(IC_(50)=15.11 nM),along with a favorable subtype selectivity profile(selectivity index z 117.23 for HDAC1),which was further verified by the Western blot analysis.Additionally,Cmpd.18 induced G2/M phase arrest and promoted apoptosis in HCT-116 cells,exerting desirable antiproliferative activity(IC_(50)=2.59 mM).Furthermore,based on long-term MD simulation trajectory,the key residues facilitating Cmpd.18's binding were identified by decomposition free energy analysis,thereby elucidating its binding mechanism.Moreover,the representative conformation analysis also indicated that Cmpd.18 could stably bind to the active pocket in an effective conformation,thus demonstrating the potential for in-depth research of the 2-(2-phenoxyethyl)pyridazin-3(2H)-one scaffold.展开更多
Carbon nanotube formation exemplifies atomically precise self-assembly,where atomic interactions dynamically engineer nanoscale architectures with emergent properties that transcend classical material boundaries.Howev...Carbon nanotube formation exemplifies atomically precise self-assembly,where atomic interactions dynamically engineer nanoscale architectures with emergent properties that transcend classical material boundaries.However,elucidating the transient molecular intermediates remains a critical mechanistic frontier.This study investigates the atomic-scale nucleation process of single-walled carbon nanotubes(SWCNTs)from acetylene on iron(Fe)clusters,utilizing GFN(-x)TB-based nanoreactor molecular dynamics simulations.The simulations reveal a consistent nucleation pathway,regardless of iron cluster size(Fe_(13),Fe_(38),Fe_(55)),where the chemisorption and dissociation of acetylene molecules on the Fe clusters lead to the formation of C_(2)H and C_(2)intermediates.These species then undergo oligomerization,initiating the growth of carbon chains.As the chains cross-link and cyclize,five-membered carbon rings are preferentially formed,which eventually evolve into six-membered rings and more complex sp2-hybridized carbon networks,resembling the cap structures of nascent SWCNTs.Although the nucleation mechanism remains similar across all cluster sizes,larger clusters show enhanced catalytic activity,leading to higher molecular weight hydrocarbons and more extensive carbocyclic networks due to their higher density of active sites per reacting molecule.Crucially,the study highlights the role of C_(2)H as the key active species in the carbon network formation process.These findings offer critical insights into the initial stages of SWCNT nucleation,contributing to a deeper understanding of the mechanisms driving SWCNT growth and guiding the development of optimized synthetic strategies.展开更多
The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation method.Results show that the steady radius of gy...The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation method.Results show that the steady radius of gyration of the polymer decreases monotonically with increasing the active force.Interestingly,the polymer forms stable compact spiral with directional rotation at the steady state when the active force is large.Both the radius of gyration and the angular velocity of the spiral are nearly independent of the cavity size,but show scaling relations with the active force and the polymer length.It is further found that the formation of the stable compact spiral in most cases is a two-step relaxation process,where the polymer first forms a metastable swelling quasi spiral and then transforms into the stable compacted spiral near the wall of the cavity.The relaxation time is mainly determined by the transformation of the swelling quasi spiral,and shows remarkable dependence on the size of the cavity.Specially,when the circumference of the circular is nearly equivalent to the polymer length,it is difficult for the polymer to form the compacted spiral,leading to a large relaxation time.The underlying mechanism of the formation of the compacted spiral is revealed.展开更多
Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the m...Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the mean-square displacement g_(3)(t)and diffusion coefficient D of ring are influenced by the salt type,electrostatic interaction strength A and salt concentration cs.D first decreases and then increases as A increases when Ais not large.At large A,D decreases with an increase in A owing to the polyelectrolyte charge reversal caused by the aggregation of ions near it.Meanwhile,g_(3)(t)exhibited intermediate oscillating behavior at moderate A in monovalent cation salt solution.The sliding dynamics of ring can be attributed to the free energy landscape for diffusion.According to the potential of mean force(PMF)of ring chain,we found that our simulation results agreed well with the theoretical results of Lifson-Jackson formula.This study can provide a practical model for the diffusion of charged particles in different dielectric and periodic media,and provides a new perspective for regulating the sliding dynamics of mechanically interlocked molecules in electrolyte solutions.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
The performance and efficiency of hydraulic excavators heavily depend on the design and optimization of their working devices.The working device,which consists of the boom,arm,and bucket,plays a crucial role in determ...The performance and efficiency of hydraulic excavators heavily depend on the design and optimization of their working devices.The working device,which consists of the boom,arm,and bucket,plays a crucial role in determining the machine's digging capacity,stability,and overall operational efficiency.This paper presents a comprehensive study on the dynamics simulation and optimization of hydraulic excavator working devices.The paper outlines the fundamental principles of dynamic modeling,incorporating multi-body dynamics and hydraulic system analysis.It further explores various simulation techniques to evaluate the performance of the working device under varying operational conditions,including load and hydraulic system effects.The study also addresses performance optimization,focusing on multi-objective optimization methods that balance multiple factors such as energy efficiency,speed,and load capacity.Additionally,the paper discusses key factors influencing performance,such as mechanical design,material properties,and operational conditions.The results of the dynamic simulations and optimization analyses demonstrate potential improvements in operational efficiency and system stability,providing a valuable framework for the design and enhancement of hydraulic excavator working devices.展开更多
Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based ...Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based on the system dynamics methodology.The introduction of Wolbachia-carrying mosquitoes aims to reduce dengue transmission by interfering with the reproductive capacity of mosquitoes,thus limiting the spread of the virus.Objective:the objective of this study is to analyze how this intervention affects not only the incidence of dengue but also the health care system,evaluating changes in the demand for medical services and the costs associated with treatment in health care institutions.Specifically,it looks at the cost per visit to an Epidemiologist,a Family Doctor,diagnostic tests,and hospitalization.Methods:the study uses simulation scenarios to model the potential impact of the Wolbachia-based intervention in reducing dengue cases and its associated health and economic burden.The scenarios also assess the optimization of resources and improvements in the health system’s response to epidemic outbreaks.The simulation model utilizes real data from the Americas region to enhance the accuracy and relevance of the results.Conclusion:The results the potential of the release of Wolbachia-carrying mosquitoes to significantly mitigate the health and economic burden of dengue,with a maximum saving of 60.15%in the best simulation scenario.The approach not only highlights scientific innovation but also demonstrates its potential influence on public policy design.The findings support the implementation of sustainable strategies to maximize the benefits of this intervention and ensure its effective integration into public health programs,contributing to better long-term dengue management.展开更多
Eu^(2+)doped fluorosilicate glass-ceramics containing BaF_(2) nanocrystals have high potential as spectral conversion materials for organic solar cells.However,it is difficult to realize the efficient design of BaF_(2...Eu^(2+)doped fluorosilicate glass-ceramics containing BaF_(2) nanocrystals have high potential as spectral conversion materials for organic solar cells.However,it is difficult to realize the efficient design of BaF_(2):Eu^(2+)doped fluorosilicate glass and to vividly observe the glass microstructure in experiment through traditional trial-and-error glass preparation method.BaF_(2):Eu^(2+)doped fluorosilicate glassceramics with high transparency,and high photoluminescence(PL)performance were predicted,designed and prepared via molecular dynamics(MD)simulation method.By MD simulation prediction,self-organized nanocrystallization was realized to inhibit the abnormal growth of nanocrystals due to[AlO_(4)]tetrahedra formed in the fluoride-oxide interface.The introduction of NaF reduces the effective phonon energy of the glass because Na+will prompt Al^(3+)to migrate from the fluoride phase to the silicate phase and interface.The local environment of Eu^(2+)is optimized by predicting the doping concentration of EuF_(3) and 2 mol%EuF3 is the best concentration in this work.Glass-ceramics sample GC2Eu as spectral conversion layer was successfully applied on organic solar cells to obtain more available visible phonons with a high photoelectric conversion efficiency(PCE).This work confirms the guidance of molecular dynamics simulation methods for fluorosilicate glasses design.展开更多
In the production process of silicone sealant,mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency.However,the silicone sealant content in mineral ...In the production process of silicone sealant,mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency.However,the silicone sealant content in mineral oil is prone to premature aging,which significantly reduces the mechanical properties of the silicone sealant and severely affects its service life.At the same time,there are few reports on the simulation research of the performance of silicone sealant.In this study,three mixed system models of crosslinking silicone sealant/plasticizer are constructed by the molecular dynamics simulationmethod,and the effect of three influencing factors,namely,crosslinking degree of silicone sealant,plasticizer content and external temperature on the mechanical properties of silicone sealant system is analyzed.The results show that at room temperature,the mechanical properties of the silicone sealant system are enhanced with the increase of its crosslinking degree;At a high crosslinking degree,with the increase of plasticizer content,themechanical properties of the silicone sealant system show an overall decreasing trend.When the methyl silicone oil in the range of 20%,themechanical properties of the silicone sealant appeared tobe a small degree of enhancement;As the temperature increases,the doped mineral oil mechanical properties of silicone sealant declined significantly,while doped with methyl silicone oil silicone sealant and doped with double-ended vinyl silicone oil silicone sealant mechanical properties have better heat resistance.It will provide scientific theoretical guidance for improving and predicting the mechanical properties of silicone sealant.展开更多
Stimuli-responsive polymers capable of rapidly altering their chain conformation in response to external stimuli exhibit broad applica-tion prospects.Experiments have shown that pressure plays a pivotal role in regula...Stimuli-responsive polymers capable of rapidly altering their chain conformation in response to external stimuli exhibit broad applica-tion prospects.Experiments have shown that pressure plays a pivotal role in regulating the microscopic chain conformation of polymers in mixed solvents,and one notable finding is that increasing the pressure can lead to the vanishing of the co-nonsolvency effect.However,the mecha-nisms underlying this phenomenon remain unclear.In this study,we systematically investigated the influence of pressure on the co-nonsolvency effect of single-chain and multi-chain homopolymers in binary mixed good-solvent systems using molecular dynamics simulations.Our results show that the co-nonsolvency-induced chain conformation transition and aggregation behavior significantly depend on pressure in allsingle-chain and multi-chain systems.In single-chain systems,at low pressures,the polymer chain maintains a collapsed state over a wide range of co-solvent fractions(x-range)owing to the co-nonsolvency effect.As the pressure increases,the x-range of the collapsed state gradually narrows,ac-companied by a progressive expansion of the chain.In multichain systems,polymer chains assemble into approximately spherical aggregates over a broad x-range at low pressures owing to the co-nonsolvency effect.Increasing the pressure reduces the x-range for forming aggregates and leads to the formation of loose aggregates or even to a state of dispersed chains at some x-range.These findings indicate that increasing the pressure can weaken or even offset the co-nonsolvency effect in some x-range,which is in good agreement with the experimental observations.Quantitative analysis of the radial density distributions and radial distribution functions reveals that,with increasing pressure,(1)the densities of both polymers and co-solvent molecules within aggregates decrease,while that of the solvent molecule increases;and(2)the effective interac-tions between the polymer and the co-solvent weaken,whereas those between the polymer and solvent strengthen.This enhances the incorpo-ration of solvent molecules within the chains,thereby weakening or even suppressing the chain aggregation.Our study not only elucidates the regulatory mechanism of pressure on the microscopic chain conformations and aggregation behaviors of polymers,but also may provide theo-retical guidance for designing smart polymericmaterials based on mixed solvents.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
基金supported by the National Key Research and Development Program of China (Grant No.2021YFC2202604)the Strategy Priority Research Program of Chinese Academy of Sciences (Grant No.XDA1502110101).
文摘The ground-based experimental tests are crucial to verify the related technologies of the drag-free satellite.This work presents a design method of the ground simulator testbed for emulating the planar dynamics of the space drag-free systems.In this paper,the planar dynamic characteristics of the drag-free satellite with double test masses are analyzed and nondimensionalized.A simulator vehicle composed of an air bearing testbed and two inverted pendulums is devised on the basic of equivalent mass and equivalent stiffness proposed firstly in this paper.And the dynamic model of the simulator equivalent to the sensitive axis motion of the test mass and the planar motion of the satellite is derived from the Euler-Lagrange method.Then,the dynamic equivalence conditions between the space prototype system and the ground model system are derived from Pi theorem.To satisfy these conditions,the scaling laws of two systems and requirements for the inverted pendulum are put forward.Besides,the corresponding control scaling laws and a closed-loop control strategy are deduced and applied to establishing the numerical simulation experiments of underactuated system.Subsequently,the comparative simulation results demonstrate the similarity of dynamical behavior between the scaled-down ground model and the space prototype.As a result,the rationality and effectiveness of the design method are proved,facilitating the ground simulation of future gravitational wave detection satellites.
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Sponsored by the Ministerial Level Foundation (070312)
文摘Based on the dynamical characteristic parameters of the real vehicle, the modehng approach ancl procedure of dynamics of vehicles are expatiated. The layout of vehicle dynamics is proposed, and the sub-models of the diesel engine, drivetrain system and vehicle multi-body dynamics are introduced. Finally, the running characteristic data of the virtual and real vehicles are compared, which shows that the dynamics model is similar closely to the real vehicle system.
基金funded by Central Guidance on Local Science and Technology Development Fund of Hebei Province,China(Grant No.:226Z2605G)the Key Project from Hebei Provincial Department of Science and Technology,China(Grant No.:21372601D)+6 种基金Graduate Student Innovation Grant Program of Hebei Medical University,China(Grant No.:XCXZZB202303)Science Research Project of Hebei Education Department,China(Grant Nos.:BJ2025046,and CYZD202501)Program for Young Scientists in the Field of Natural Science of Hebei Medical University,China(Program Nos.:CYCZ2023010,CYCZ2023011,CYQD2021011,CYQD2021015 and CYQD2023012)Traditional Chinese Medicine Administration Project of Hebei Province,China(Project No.:2025427)National Natural Science Foundation of China(Grant No.:32100771)the Hebei Provincial Medical Science Research Project Plan,China(Project Nos.:20240241 and 20220200)Shijiazhuang Science and Technology Bureau,China(Grant Nos.:241200487A,and 07202204).
文摘Increasing evidence showed that histone deacetylase 6(HDAC6)dysfunction is directly associated with the onset and progression of various diseases,especially cancers,making the development of HDAC6-targeted anti-tumor agents a research hotspot.In this study,artificial intelligence(AI)technology and molecular simulation strategies were fully integrated to construct an efficient and precise drug screening pipeline,which combined Voting strategy based on compound-protein interaction(CPI)prediction models,cascade molecular docking,and molecular dynamic(MD)simulations.The biological potential of the screened compounds was further evaluated through enzymatic and cellular activity assays.Among the identified compounds,Cmpd.18 exhibited more potent HDAC6 enzyme inhibitory activity(IC_(50)=5.41 nM)than that of tubastatin A(TubA)(IC_(50)=15.11 nM),along with a favorable subtype selectivity profile(selectivity index z 117.23 for HDAC1),which was further verified by the Western blot analysis.Additionally,Cmpd.18 induced G2/M phase arrest and promoted apoptosis in HCT-116 cells,exerting desirable antiproliferative activity(IC_(50)=2.59 mM).Furthermore,based on long-term MD simulation trajectory,the key residues facilitating Cmpd.18's binding were identified by decomposition free energy analysis,thereby elucidating its binding mechanism.Moreover,the representative conformation analysis also indicated that Cmpd.18 could stably bind to the active pocket in an effective conformation,thus demonstrating the potential for in-depth research of the 2-(2-phenoxyethyl)pyridazin-3(2H)-one scaffold.
基金supported by the National Key R&D Program of China(2022YFA1604100)the National Natural Science Foundation of China(22302220,22372187,1972157,21972160,22402218)+2 种基金the National Science Fund for Distinguished Young Scholars of China(22225206)the Fundamental Research Program of Shanxi Province(202203021222403)the Youth Innovation Promotion Association CAS(2020179)。
文摘Carbon nanotube formation exemplifies atomically precise self-assembly,where atomic interactions dynamically engineer nanoscale architectures with emergent properties that transcend classical material boundaries.However,elucidating the transient molecular intermediates remains a critical mechanistic frontier.This study investigates the atomic-scale nucleation process of single-walled carbon nanotubes(SWCNTs)from acetylene on iron(Fe)clusters,utilizing GFN(-x)TB-based nanoreactor molecular dynamics simulations.The simulations reveal a consistent nucleation pathway,regardless of iron cluster size(Fe_(13),Fe_(38),Fe_(55)),where the chemisorption and dissociation of acetylene molecules on the Fe clusters lead to the formation of C_(2)H and C_(2)intermediates.These species then undergo oligomerization,initiating the growth of carbon chains.As the chains cross-link and cyclize,five-membered carbon rings are preferentially formed,which eventually evolve into six-membered rings and more complex sp2-hybridized carbon networks,resembling the cap structures of nascent SWCNTs.Although the nucleation mechanism remains similar across all cluster sizes,larger clusters show enhanced catalytic activity,leading to higher molecular weight hydrocarbons and more extensive carbocyclic networks due to their higher density of active sites per reacting molecule.Crucially,the study highlights the role of C_(2)H as the key active species in the carbon network formation process.These findings offer critical insights into the initial stages of SWCNT nucleation,contributing to a deeper understanding of the mechanisms driving SWCNT growth and guiding the development of optimized synthetic strategies.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY20A040004)the National Natural Science Foundation of China(Nos.22203060 and 11974305).
文摘The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation method.Results show that the steady radius of gyration of the polymer decreases monotonically with increasing the active force.Interestingly,the polymer forms stable compact spiral with directional rotation at the steady state when the active force is large.Both the radius of gyration and the angular velocity of the spiral are nearly independent of the cavity size,but show scaling relations with the active force and the polymer length.It is further found that the formation of the stable compact spiral in most cases is a two-step relaxation process,where the polymer first forms a metastable swelling quasi spiral and then transforms into the stable compacted spiral near the wall of the cavity.The relaxation time is mainly determined by the transformation of the swelling quasi spiral,and shows remarkable dependence on the size of the cavity.Specially,when the circumference of the circular is nearly equivalent to the polymer length,it is difficult for the polymer to form the compacted spiral,leading to a large relaxation time.The underlying mechanism of the formation of the compacted spiral is revealed.
基金supported by the National Natural Science Foundation of China(Nos.22173080,22403062,and22363005)the Jiangxi Provincial Natural Science Foundation(No.20202BABL203015)。
文摘Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the mean-square displacement g_(3)(t)and diffusion coefficient D of ring are influenced by the salt type,electrostatic interaction strength A and salt concentration cs.D first decreases and then increases as A increases when Ais not large.At large A,D decreases with an increase in A owing to the polyelectrolyte charge reversal caused by the aggregation of ions near it.Meanwhile,g_(3)(t)exhibited intermediate oscillating behavior at moderate A in monovalent cation salt solution.The sliding dynamics of ring can be attributed to the free energy landscape for diffusion.According to the potential of mean force(PMF)of ring chain,we found that our simulation results agreed well with the theoretical results of Lifson-Jackson formula.This study can provide a practical model for the diffusion of charged particles in different dielectric and periodic media,and provides a new perspective for regulating the sliding dynamics of mechanically interlocked molecules in electrolyte solutions.
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.
文摘The performance and efficiency of hydraulic excavators heavily depend on the design and optimization of their working devices.The working device,which consists of the boom,arm,and bucket,plays a crucial role in determining the machine's digging capacity,stability,and overall operational efficiency.This paper presents a comprehensive study on the dynamics simulation and optimization of hydraulic excavator working devices.The paper outlines the fundamental principles of dynamic modeling,incorporating multi-body dynamics and hydraulic system analysis.It further explores various simulation techniques to evaluate the performance of the working device under varying operational conditions,including load and hydraulic system effects.The study also addresses performance optimization,focusing on multi-objective optimization methods that balance multiple factors such as energy efficiency,speed,and load capacity.Additionally,the paper discusses key factors influencing performance,such as mechanical design,material properties,and operational conditions.The results of the dynamic simulations and optimization analyses demonstrate potential improvements in operational efficiency and system stability,providing a valuable framework for the design and enhancement of hydraulic excavator working devices.
文摘Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based on the system dynamics methodology.The introduction of Wolbachia-carrying mosquitoes aims to reduce dengue transmission by interfering with the reproductive capacity of mosquitoes,thus limiting the spread of the virus.Objective:the objective of this study is to analyze how this intervention affects not only the incidence of dengue but also the health care system,evaluating changes in the demand for medical services and the costs associated with treatment in health care institutions.Specifically,it looks at the cost per visit to an Epidemiologist,a Family Doctor,diagnostic tests,and hospitalization.Methods:the study uses simulation scenarios to model the potential impact of the Wolbachia-based intervention in reducing dengue cases and its associated health and economic burden.The scenarios also assess the optimization of resources and improvements in the health system’s response to epidemic outbreaks.The simulation model utilizes real data from the Americas region to enhance the accuracy and relevance of the results.Conclusion:The results the potential of the release of Wolbachia-carrying mosquitoes to significantly mitigate the health and economic burden of dengue,with a maximum saving of 60.15%in the best simulation scenario.The approach not only highlights scientific innovation but also demonstrates its potential influence on public policy design.The findings support the implementation of sustainable strategies to maximize the benefits of this intervention and ensure its effective integration into public health programs,contributing to better long-term dengue management.
基金Project supported by the National Natural Science Foundation of China(52172008,51872255)the Key Research and Development Project of Zhejiang Province(2021C01174)。
文摘Eu^(2+)doped fluorosilicate glass-ceramics containing BaF_(2) nanocrystals have high potential as spectral conversion materials for organic solar cells.However,it is difficult to realize the efficient design of BaF_(2):Eu^(2+)doped fluorosilicate glass and to vividly observe the glass microstructure in experiment through traditional trial-and-error glass preparation method.BaF_(2):Eu^(2+)doped fluorosilicate glassceramics with high transparency,and high photoluminescence(PL)performance were predicted,designed and prepared via molecular dynamics(MD)simulation method.By MD simulation prediction,self-organized nanocrystallization was realized to inhibit the abnormal growth of nanocrystals due to[AlO_(4)]tetrahedra formed in the fluoride-oxide interface.The introduction of NaF reduces the effective phonon energy of the glass because Na+will prompt Al^(3+)to migrate from the fluoride phase to the silicate phase and interface.The local environment of Eu^(2+)is optimized by predicting the doping concentration of EuF_(3) and 2 mol%EuF3 is the best concentration in this work.Glass-ceramics sample GC2Eu as spectral conversion layer was successfully applied on organic solar cells to obtain more available visible phonons with a high photoelectric conversion efficiency(PCE).This work confirms the guidance of molecular dynamics simulation methods for fluorosilicate glasses design.
基金supported by The Guangxi Scholarship Fund of Guangxi Education Department(GED),Guangxi Key Research and Development Project(Grant No.Guike AB24010217)the Major Special Project of Guangxi Science and Technology(GrantNo.Guike AA23062020)+1 种基金the Guangxi Science and Technology Base and Talent Project(Grant No.Guike AD20297016)the Guangxi Minzu University Startup Project for Talent Introduction in 2019(Grant No.2019KJQD11).
文摘In the production process of silicone sealant,mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency.However,the silicone sealant content in mineral oil is prone to premature aging,which significantly reduces the mechanical properties of the silicone sealant and severely affects its service life.At the same time,there are few reports on the simulation research of the performance of silicone sealant.In this study,three mixed system models of crosslinking silicone sealant/plasticizer are constructed by the molecular dynamics simulationmethod,and the effect of three influencing factors,namely,crosslinking degree of silicone sealant,plasticizer content and external temperature on the mechanical properties of silicone sealant system is analyzed.The results show that at room temperature,the mechanical properties of the silicone sealant system are enhanced with the increase of its crosslinking degree;At a high crosslinking degree,with the increase of plasticizer content,themechanical properties of the silicone sealant system show an overall decreasing trend.When the methyl silicone oil in the range of 20%,themechanical properties of the silicone sealant appeared tobe a small degree of enhancement;As the temperature increases,the doped mineral oil mechanical properties of silicone sealant declined significantly,while doped with methyl silicone oil silicone sealant and doped with double-ended vinyl silicone oil silicone sealant mechanical properties have better heat resistance.It will provide scientific theoretical guidance for improving and predicting the mechanical properties of silicone sealant.
基金support provided by the National Natural Science Foundation of China(Nos.22173051,21829301,21774066),PCSIRT(IRT1257)the College Discipline Innovation and Intelligence Introduction Program(111 Project(B16027)+2 种基金the International Cooperation Base(No.2016D01025)Tianjin International Joint Research and Development Center)P.Zhang acknowledges the financial support provided by NSFC(No.22473024).
文摘Stimuli-responsive polymers capable of rapidly altering their chain conformation in response to external stimuli exhibit broad applica-tion prospects.Experiments have shown that pressure plays a pivotal role in regulating the microscopic chain conformation of polymers in mixed solvents,and one notable finding is that increasing the pressure can lead to the vanishing of the co-nonsolvency effect.However,the mecha-nisms underlying this phenomenon remain unclear.In this study,we systematically investigated the influence of pressure on the co-nonsolvency effect of single-chain and multi-chain homopolymers in binary mixed good-solvent systems using molecular dynamics simulations.Our results show that the co-nonsolvency-induced chain conformation transition and aggregation behavior significantly depend on pressure in allsingle-chain and multi-chain systems.In single-chain systems,at low pressures,the polymer chain maintains a collapsed state over a wide range of co-solvent fractions(x-range)owing to the co-nonsolvency effect.As the pressure increases,the x-range of the collapsed state gradually narrows,ac-companied by a progressive expansion of the chain.In multichain systems,polymer chains assemble into approximately spherical aggregates over a broad x-range at low pressures owing to the co-nonsolvency effect.Increasing the pressure reduces the x-range for forming aggregates and leads to the formation of loose aggregates or even to a state of dispersed chains at some x-range.These findings indicate that increasing the pressure can weaken or even offset the co-nonsolvency effect in some x-range,which is in good agreement with the experimental observations.Quantitative analysis of the radial density distributions and radial distribution functions reveals that,with increasing pressure,(1)the densities of both polymers and co-solvent molecules within aggregates decrease,while that of the solvent molecule increases;and(2)the effective interac-tions between the polymer and the co-solvent weaken,whereas those between the polymer and solvent strengthen.This enhances the incorpo-ration of solvent molecules within the chains,thereby weakening or even suppressing the chain aggregation.Our study not only elucidates the regulatory mechanism of pressure on the microscopic chain conformations and aggregation behaviors of polymers,but also may provide theo-retical guidance for designing smart polymericmaterials based on mixed solvents.
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.
