In views of system theory, information theory and cybernetics, this paper utilizes the method of the system dynamics to create the field resources utilizing system main diagram of causation and system dynamic followin...In views of system theory, information theory and cybernetics, this paper utilizes the method of the system dynamics to create the field resources utilizing system main diagram of causation and system dynamic following diagram, uses the Dynamo computer language to construct the dynamic emulating model, and with the help of computer, completes the computer dynamic simulating of the field resources utilizing system. This paper utilizes the method of AHP （analytical hierarchy process） to seek for the most excellent program of Nanpi County＇s field resources utilizing structure. So we can provide scientific basis for leaders to make scientific management and strategic decision and the limited field resources will bring out the most benefit for society, economics and ecological.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
The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behav...The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.展开更多
The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of i...The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of its influence on fluid migration are of crucial importance.While previous studies have revealed that salinity changes can modulate fluid migration,the underlying mechanisms remain poorly understood.We employ molecular dynamics simulations to elucidate how salinity variations in ore-forming fluids modulate the adsorption onto calcite nanopore walls,thereby revealing the microscopic mechanisms governing ore fluid transport through calcite nano-fractures.The results show that the adsorption energy Eint of the solution on the calcite surface increased from -14,948.84±182.48 kcal/mol to -12,144.08±118.2 kcal/mol as salinity increased,which is conducive to the long-range transport of the fluid in the calcite nanopore.展开更多
This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. Th...This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. The results indicate that the dislocation propagates and the stress transfers not only along the fiber axis but also between adjacent molecular chains through hydrogen bonds, demonstrating their influence on the yield behavior. As the degree of polymerization increases, breakage of covalent bonds and interchain slippage contribute to the yield of fibers together. This work provides theoretical guidance for the design and manufacturing of high-performance fibers.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
Regional climate simulation can generally be improved by using an RCM nested within a coarser-resolution GCM.However, whether or not it can also be improved by the direct use of a state-of-the-art GCM with very fine r...Regional climate simulation can generally be improved by using an RCM nested within a coarser-resolution GCM.However, whether or not it can also be improved by the direct use of a state-of-the-art GCM with very fine resolution, close to that of an RCM, and, if so, which is the better approach, are open questions. These questions are important for understanding and using these two kinds of simulation approaches, but have not yet been investigated. Accordingly, the present reported work compared simulation results over China from a very-fine-resolution GCM（VFRGCM） and from RCM dynamical downscaling. The results showed that：（1） The VFRGCM reproduces the climatologies and trends of both air temperature and precipitation, as well as inter-monthly variations of air temperature in terms of spatial pattern and amount, closer to observations than the coarse-resolution version of the GCM. This is not the case, however, for the inter-monthly variations of precipitation.（2） The VFRGCM captures the climatology, trend, and inter-monthly variation of air temperature, as well as the trend in precipitation, more reasonably than the RCM dynamical downscaling method.（3） The RCM dynamical downscaling method performs better than the VFRGCM in terms of the climatology and inter-monthly variation of precipitation. Overall,the results suggest that VFRGCMs possess great potential with regard to their application in climate simulation in the future,and the RCM dynamical downscaling method is still dominant in terms of regional precipitation simulation.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
Objective To evaluate the antibacterial potential of bioactive compounds from Persicaria hydropiper(L.)(P.hydropiper)against bacterial virulence proteins through molecular docking(MD)and experimental validation.Method...Objective To evaluate the antibacterial potential of bioactive compounds from Persicaria hydropiper(L.)(P.hydropiper)against bacterial virulence proteins through molecular docking(MD)and experimental validation.Methods Six bioactive compounds from P.hydropiper were investigated:catechin(CAT1),hyperin(HYP1),ombuin(OMB1),pinosylvin(PSV1),quercetin 3-sulfate(QSF1),and scutellarein(SCR1).Their binding affinities and potential binding pockets were assessed through MD against four bacterial target proteins with Protein Data Bank identifiers(PDB IDs):topoisomerase IV from Escherichia coli(E.coli)(PDB ID:3FV5),Staphylococcus aureus(S.aureus)gyrase ATPase binding domain(PDB ID:3U2K),CviR from Chromobacterium violaceum(C.violaceum)(PDB ID:3QP1),and glycosyl hydrolase from Pseudomonas aeruginosa(P.aeruginosa)(PDB ID:5BX9).Molecular dynamics simulations(MDS)were performed on the most promising compound-protein complexes for 50 nanoseconds(ns).Drug-likeness was evaluated using Lipinski's Rule of Five(RO5),followed by absorption,distribution,metabolism,excretion,and toxicity(ADMET)analysis using SwissADME and pkCSM web servers.Antibacterial activity was evaluated through disc diffusion assays,testing both individual compounds and combinations with conventional antibiotics[cefotaxime(CTX1,30μg/disc),ceftazidime(CAZ1,30μg/disc),and piperacillin(PIP1,100μg/disc)].Results MD revealed strong binding affinity(ranging from-9.3 to-5.9 kcal/mol)for all compounds,with CAT1 showing exceptional binding to 3QP1(-9.3 kcal/mol)and 5BX9(-8.4 kcal/mol).MDS confirmed the stability of CAT1-protein complexes with binding free energies of-84.71 kJ/mol(5BX9-CAT1)and-95.59 kJ/mol(3QP1-CAT1).Five compounds(CAT1,SCR1,PSV1,OMB1,and QSF1)complied with Lipinski's RO5 and showed favorable ADMET profiles.All compounds were non-carcinogenic,with CAT1 classified in the lowest toxicity class(VI).In antibacterial assays,CAT1 demonstrated significant activity against both gram-positive bacteria[Streptococcus pneumoniae(S.pneumoniae),S.aureus,and Bacillus cereus(B.cereus)][zone diameter of inhibition(ZDI):10-22 mm]and gram-negative bacteria[Acinetobacter baumannii(A.baumannii),E.coli,and P.aeruginosa](ZDI:14-27 mm).Synergistic effects were observed when CAT1 was combined with antibiotics and the growth inhibitory indices(GII)was 0.69-1.00.Conclusion P.hydropiper bioactive compounds,particularly CAT1,show promising antibacterial potential through multiple mechanisms,including direct inhibition of bacterial virulence proteins and synergistic activity with conventional antibiotics.The favorable pharmacological properties and low toxicity profiles support their potential development as therapeutic agents against bacterial infections.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
As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their ...As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms.Physical simulation test represents an efficacious methodology.However,there is currently a lack of simulation devices that can effectively simulate two types of dynamic impact phenomena,including high stress and fault slip dynamic impact.To solve aforementioned issues,the physical simulation test system for dynamic impact in deep roadways developed by authors is employed to carry out comparative tests of high stress and fault slip dynamic impact.The phenomena of high stress and fault slip dynamic impact are reproduced successfully.A comparative analysis is conducted on dynamic phenomena,stress evolution,roadway deformation,and support force.The high stress dynamic impact roadway instability mode,which is characterized by the release of high energy accompanied by symmetric damage,and the fault slip dynamic impact roadway instability mode,which is characterized by the propagation of unilateral stress waves accompanied by asymmetric damage,are clarified.On the basis,the differentiated control concepts for different types of dynamic impact in deep roadways are proposed.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
Heavy oil,constituting a significant portion of global oil reserves,presents unique challenges in extraction and processing due to its high viscosity,largely influenced by asphaltenes and their heteroatom content.This...Heavy oil,constituting a significant portion of global oil reserves,presents unique challenges in extraction and processing due to its high viscosity,largely influenced by asphaltenes and their heteroatom content.This study employs molecular dynamics(MD)simulations to investigate the selfaggregation and adsorption mechanisms of heteroatom/non-heteroatom asphaltenes,comparing linear and island structural configurations.Key findings reveal that linear heteroatom asphaltenes form dense,multi-layered aggregates,while island heteroatom asphaltenes exhibit stronger aggregation energy.On solid surfaces,linear asphaltenes display multi-layered adsorption,whereas island asphaltenes adopt a dispersed structure with higher adsorption energy,making them more resistant to removal.Compared to non-heteroatom asphaltenes,heteroatom asphaltenes significantly enhance the aggregation energy of the asphaltene itself and the interaction energy with light oil components,reducing the diffusion capacity of oil droplets and increasing viscosity.Although the viscosity of island heteroatom asphaltene oil drops is the largest,the role of heteroatom in linear asphaltene is more obvious,and linear heteroatom asphaltene and non-heteroatom show great differences in properties.Additionally,heteroatom-containing oil droplets exhibit stronger interactions with solid surfaces,driven by the influence of heteroatom asphaltenes on lighter oil components.These insights provide a deeper understanding of heavy oil viscosity mechanisms,offering a foundation for developing targeted viscosity-reduction strategies and optimizing heavy oil recovery and processing techniques.展开更多
This study explores green and low-viscosity deep eutectic solvents(DESs) for the efficient extraction of quinoline(QUI) from wash oil.The hydrogen bond donors and acceptors constituting DESs were initially screened ba...This study explores green and low-viscosity deep eutectic solvents(DESs) for the efficient extraction of quinoline(QUI) from wash oil.The hydrogen bond donors and acceptors constituting DESs were initially screened based on thermodynamic properties predicted by the conductor-like screening model for real solvents(COSMO-RS),followed by further selection considering the viscosity and cost of the formed DESs.Phase equilibrium experiments showed that the DES composed of triethylmethylammonium chloride and formic acid exhibited the best extraction performance among the selected candidates.Key extraction parameters were optimized experimentally,achieving a maximum QUI extraction efficiency of 97.18% under mild conditions.Molecular dynamics simulations revealed that the interactions between quaternary ammonium cations and QUI play a crucial role in the extraction mechanism.This study provides insights into the use of DESs for QUI extraction and demonstrates their potential for application to other coal tar derivatives.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
In nature,cavitation bubbles typically appear in clusters,engaging in interactions that create a variety of dynamicmotion patterns.To better understand the behavior ofmultiple bubble collapses and the mechanisms of in...In nature,cavitation bubbles typically appear in clusters,engaging in interactions that create a variety of dynamicmotion patterns.To better understand the behavior ofmultiple bubble collapses and the mechanisms of interbubble interaction,this study employs molecular dynamics simulation combined with a coarse-grained force field.By focusing on collapsemorphology,local density,and pressure,it elucidates how the number and arrangement of bubbles influence the collapse process.The mechanisms behind inter-bubble interactions are also considered.The findings indicate that the collapse speed of unbounded bubbles located in lateral regions is greater than that of the bubbles in the center.Moreover,it is shown that asymmetrical bubble distributions lead to a shorter collapse time overall.展开更多
This study investigates using an antioxidation copper particle-free paste,formulated with self-reducing copper formate,for Cu-Cu bonding in electronic packaging applications.The research highlights the oxidation resis...This study investigates using an antioxidation copper particle-free paste,formulated with self-reducing copper formate,for Cu-Cu bonding in electronic packaging applications.The research highlights the oxidation resistance of copper formate compared to traditional copper nanoparticles(CuNPs)and its ability to generate CuNPs through thermal decomposition.Experimental results demonstrate that the sintering process benefits from releasing reductive gases during decomposition,improving joint quality with reduced porosity and enhanced mechanical strength at elevated temperatures.Molecular dynamics simulations further elucidate the sintering behavior of CuNPs,providing significant insights into pore collapse,atomic mobility,and neck formation.The findings indicate that increased temperatures enhance surface and bulk diffusion,facilitating robust particle connections.Overall,this work establishes the potential of copper formate for achieving reliable interconnects in semiconductor devices,paving the way for advancements in material formulations for direct copper–copper bonding.展开更多
The high-speed winding spindle employs a flexible support system incorporating rubber O-rings.By precisely configuring the structural parameters and the number of the O-rings,the spindle can stably surpass its critica...The high-speed winding spindle employs a flexible support system incorporating rubber O-rings.By precisely configuring the structural parameters and the number of the O-rings,the spindle can stably surpass its critical speed points and maintain operational stability across the entire working speed range.However,the support stiffness and damping of rubber O-rings exhibit significant nonlinear frequency dependence.Conventional experimental methods for deriving equivalent stiffness and damping,based on the principle of the forced non-resonance method,require fabricating custom setups for each O-ring specification and conducting vibration tests at varying frequencies,resulting in low efficiency and high costs.This study proposes a hybrid simulation-experimental method for dynamic parameter identification.Firstly,the frequency-dependent dynamic parameters of a specific O-ring support system are experimentally obtained.Subsequently,a corresponding parametric finite element model is established to simulate and solve the equivalent elastic modulus and equivalent stiffness-damping coefficient of this O-ring support system.Ultimately,after iterative simulation,the simulated and experimental results achieve a 99.7%agreement.The parametric finite element model developed herein can directly simulate and inversely estimate frequency-dependent dynamic parameters for O-rings of different specifications but identical elastic modulus.展开更多
文摘In views of system theory, information theory and cybernetics, this paper utilizes the method of the system dynamics to create the field resources utilizing system main diagram of causation and system dynamic following diagram, uses the Dynamo computer language to construct the dynamic emulating model, and with the help of computer, completes the computer dynamic simulating of the field resources utilizing system. This paper utilizes the method of AHP （analytical hierarchy process） to seek for the most excellent program of Nanpi County＇s field resources utilizing structure. So we can provide scientific basis for leaders to make scientific management and strategic decision and the limited field resources will bring out the most benefit for society, economics and ecological.
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 National Natural Science Foundation of China(Nos.22341304,22303100 and 12205270)the National Key R&D Program of China(Nos.2023YFA1008800 and 2020YFA0713601)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC0180303)。
文摘The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.
基金financed jointly by the National Major Science and Technology Special Project on Deep Earth Exploration(2024ZD1001701-5)the National Natural Science Foundation of China(42472127,42172086)+2 种基金the Yunnan Major Project of Basic Research(202401BN070001-002)Yunnan Mineral Resources Prediction and Evaluation Engineering Research Center(2011)Innovation Team Program of Kunming University of Science and Technology,Yunnan Province。
文摘The migration mechanisms of ore-forming fluids have long been a focus in the field of ore deposit studies.Calcite is ubiquitously present in various types of rocks in the lithosphere,and the underlying mechanisms of its influence on fluid migration are of crucial importance.While previous studies have revealed that salinity changes can modulate fluid migration,the underlying mechanisms remain poorly understood.We employ molecular dynamics simulations to elucidate how salinity variations in ore-forming fluids modulate the adsorption onto calcite nanopore walls,thereby revealing the microscopic mechanisms governing ore fluid transport through calcite nano-fractures.The results show that the adsorption energy Eint of the solution on the calcite surface increased from -14,948.84±182.48 kcal/mol to -12,144.08±118.2 kcal/mol as salinity increased,which is conducive to the long-range transport of the fluid in the calcite nanopore.
基金financially supported by the National Natural Science Foundation of China(Nos.22473105 and 22341302).
文摘This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. The results indicate that the dislocation propagates and the stress transfers not only along the fiber axis but also between adjacent molecular chains through hydrogen bonds, demonstrating their influence on the yield behavior. As the degree of polymerization increases, breakage of covalent bonds and interchain slippage contribute to the yield of fibers together. This work provides theoretical guidance for the design and manufacturing of high-performance fibers.
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.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos. 41130103, 41421004 and 41405087)
文摘Regional climate simulation can generally be improved by using an RCM nested within a coarser-resolution GCM.However, whether or not it can also be improved by the direct use of a state-of-the-art GCM with very fine resolution, close to that of an RCM, and, if so, which is the better approach, are open questions. These questions are important for understanding and using these two kinds of simulation approaches, but have not yet been investigated. Accordingly, the present reported work compared simulation results over China from a very-fine-resolution GCM（VFRGCM） and from RCM dynamical downscaling. The results showed that：（1） The VFRGCM reproduces the climatologies and trends of both air temperature and precipitation, as well as inter-monthly variations of air temperature in terms of spatial pattern and amount, closer to observations than the coarse-resolution version of the GCM. This is not the case, however, for the inter-monthly variations of precipitation.（2） The VFRGCM captures the climatology, trend, and inter-monthly variation of air temperature, as well as the trend in precipitation, more reasonably than the RCM dynamical downscaling method.（3） The RCM dynamical downscaling method performs better than the VFRGCM in terms of the climatology and inter-monthly variation of precipitation. Overall,the results suggest that VFRGCMs possess great potential with regard to their application in climate simulation in the future,and the RCM dynamical downscaling method is still dominant in terms of regional precipitation simulation.
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Research Grants of Senior Research Fellowship in favor of first author(Gloak Majumdar)from Council of Scientific and Industrial Research(CSIR,New Delhi,Government of India)(CSIR-SRF)with Award No.09/1151/(0008)2020-EMR-I.
文摘Objective To evaluate the antibacterial potential of bioactive compounds from Persicaria hydropiper(L.)(P.hydropiper)against bacterial virulence proteins through molecular docking(MD)and experimental validation.Methods Six bioactive compounds from P.hydropiper were investigated:catechin(CAT1),hyperin(HYP1),ombuin(OMB1),pinosylvin(PSV1),quercetin 3-sulfate(QSF1),and scutellarein(SCR1).Their binding affinities and potential binding pockets were assessed through MD against four bacterial target proteins with Protein Data Bank identifiers(PDB IDs):topoisomerase IV from Escherichia coli(E.coli)(PDB ID:3FV5),Staphylococcus aureus(S.aureus)gyrase ATPase binding domain(PDB ID:3U2K),CviR from Chromobacterium violaceum(C.violaceum)(PDB ID:3QP1),and glycosyl hydrolase from Pseudomonas aeruginosa(P.aeruginosa)(PDB ID:5BX9).Molecular dynamics simulations(MDS)were performed on the most promising compound-protein complexes for 50 nanoseconds(ns).Drug-likeness was evaluated using Lipinski's Rule of Five(RO5),followed by absorption,distribution,metabolism,excretion,and toxicity(ADMET)analysis using SwissADME and pkCSM web servers.Antibacterial activity was evaluated through disc diffusion assays,testing both individual compounds and combinations with conventional antibiotics[cefotaxime(CTX1,30μg/disc),ceftazidime(CAZ1,30μg/disc),and piperacillin(PIP1,100μg/disc)].Results MD revealed strong binding affinity(ranging from-9.3 to-5.9 kcal/mol)for all compounds,with CAT1 showing exceptional binding to 3QP1(-9.3 kcal/mol)and 5BX9(-8.4 kcal/mol).MDS confirmed the stability of CAT1-protein complexes with binding free energies of-84.71 kJ/mol(5BX9-CAT1)and-95.59 kJ/mol(3QP1-CAT1).Five compounds(CAT1,SCR1,PSV1,OMB1,and QSF1)complied with Lipinski's RO5 and showed favorable ADMET profiles.All compounds were non-carcinogenic,with CAT1 classified in the lowest toxicity class(VI).In antibacterial assays,CAT1 demonstrated significant activity against both gram-positive bacteria[Streptococcus pneumoniae(S.pneumoniae),S.aureus,and Bacillus cereus(B.cereus)][zone diameter of inhibition(ZDI):10-22 mm]and gram-negative bacteria[Acinetobacter baumannii(A.baumannii),E.coli,and P.aeruginosa](ZDI:14-27 mm).Synergistic effects were observed when CAT1 was combined with antibiotics and the growth inhibitory indices(GII)was 0.69-1.00.Conclusion P.hydropiper bioactive compounds,particularly CAT1,show promising antibacterial potential through multiple mechanisms,including direct inhibition of bacterial virulence proteins and synergistic activity with conventional antibiotics.The favorable pharmacological properties and low toxicity profiles support their potential development as therapeutic agents against bacterial infections.
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 Natural Science Foundation of China(Nos.U24A2088,42177130,42277174,and 42477166).
文摘As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms.Physical simulation test represents an efficacious methodology.However,there is currently a lack of simulation devices that can effectively simulate two types of dynamic impact phenomena,including high stress and fault slip dynamic impact.To solve aforementioned issues,the physical simulation test system for dynamic impact in deep roadways developed by authors is employed to carry out comparative tests of high stress and fault slip dynamic impact.The phenomena of high stress and fault slip dynamic impact are reproduced successfully.A comparative analysis is conducted on dynamic phenomena,stress evolution,roadway deformation,and support force.The high stress dynamic impact roadway instability mode,which is characterized by the release of high energy accompanied by symmetric damage,and the fault slip dynamic impact roadway instability mode,which is characterized by the propagation of unilateral stress waves accompanied by asymmetric damage,are clarified.On the basis,the differentiated control concepts for different types of dynamic impact in deep roadways are proposed.
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 financially by the National Natural Science Foundation of China(No.52204069,No.22306171)the Natural Science Foundation of Zhejiang Province(No.LQ24B070005)the Jinhua Natural Science Foundation of China(2023-4-024)。
文摘Heavy oil,constituting a significant portion of global oil reserves,presents unique challenges in extraction and processing due to its high viscosity,largely influenced by asphaltenes and their heteroatom content.This study employs molecular dynamics(MD)simulations to investigate the selfaggregation and adsorption mechanisms of heteroatom/non-heteroatom asphaltenes,comparing linear and island structural configurations.Key findings reveal that linear heteroatom asphaltenes form dense,multi-layered aggregates,while island heteroatom asphaltenes exhibit stronger aggregation energy.On solid surfaces,linear asphaltenes display multi-layered adsorption,whereas island asphaltenes adopt a dispersed structure with higher adsorption energy,making them more resistant to removal.Compared to non-heteroatom asphaltenes,heteroatom asphaltenes significantly enhance the aggregation energy of the asphaltene itself and the interaction energy with light oil components,reducing the diffusion capacity of oil droplets and increasing viscosity.Although the viscosity of island heteroatom asphaltene oil drops is the largest,the role of heteroatom in linear asphaltene is more obvious,and linear heteroatom asphaltene and non-heteroatom show great differences in properties.Additionally,heteroatom-containing oil droplets exhibit stronger interactions with solid surfaces,driven by the influence of heteroatom asphaltenes on lighter oil components.These insights provide a deeper understanding of heavy oil viscosity mechanisms,offering a foundation for developing targeted viscosity-reduction strategies and optimizing heavy oil recovery and processing techniques.
基金financially supported by the Natural Science Foundation of Shanxi Province (20210302123167)National Key Research and Development Program (2022YFC3902505)。
文摘This study explores green and low-viscosity deep eutectic solvents(DESs) for the efficient extraction of quinoline(QUI) from wash oil.The hydrogen bond donors and acceptors constituting DESs were initially screened based on thermodynamic properties predicted by the conductor-like screening model for real solvents(COSMO-RS),followed by further selection considering the viscosity and cost of the formed DESs.Phase equilibrium experiments showed that the DES composed of triethylmethylammonium chloride and formic acid exhibited the best extraction performance among the selected candidates.Key extraction parameters were optimized experimentally,achieving a maximum QUI extraction efficiency of 97.18% under mild conditions.Molecular dynamics simulations revealed that the interactions between quaternary ammonium cations and QUI play a crucial role in the extraction mechanism.This study provides insights into the use of DESs for QUI extraction and demonstrates their potential for application to other coal tar derivatives.
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 Natural Science Foundation of China[U20A20292]Shandong Province Science andTechnology SMES InnovationAbility Improvement Project[2023TSGC0005]China Postdoctoral Science Foundation[2024M752697].
文摘In nature,cavitation bubbles typically appear in clusters,engaging in interactions that create a variety of dynamicmotion patterns.To better understand the behavior ofmultiple bubble collapses and the mechanisms of interbubble interaction,this study employs molecular dynamics simulation combined with a coarse-grained force field.By focusing on collapsemorphology,local density,and pressure,it elucidates how the number and arrangement of bubbles influence the collapse process.The mechanisms behind inter-bubble interactions are also considered.The findings indicate that the collapse speed of unbounded bubbles located in lateral regions is greater than that of the bubbles in the center.Moreover,it is shown that asymmetrical bubble distributions lead to a shorter collapse time overall.
基金financially supported by the Shenzhen Science and Technology Project(GXWD20220818163456002)the Key-Area Research and Development Program of Guangdong Province(No.2022B0701180002)+1 种基金the Sauvage Laboratory for Smart Materials of Harbin Institute of Technology(Shenzhen)the Guangdong Province College Students Science and Technology Innovation Cultivation Special Project.
文摘This study investigates using an antioxidation copper particle-free paste,formulated with self-reducing copper formate,for Cu-Cu bonding in electronic packaging applications.The research highlights the oxidation resistance of copper formate compared to traditional copper nanoparticles(CuNPs)and its ability to generate CuNPs through thermal decomposition.Experimental results demonstrate that the sintering process benefits from releasing reductive gases during decomposition,improving joint quality with reduced porosity and enhanced mechanical strength at elevated temperatures.Molecular dynamics simulations further elucidate the sintering behavior of CuNPs,providing significant insights into pore collapse,atomic mobility,and neck formation.The findings indicate that increased temperatures enhance surface and bulk diffusion,facilitating robust particle connections.Overall,this work establishes the potential of copper formate for achieving reliable interconnects in semiconductor devices,paving the way for advancements in material formulations for direct copper–copper bonding.
基金National Key R&D Program of China(No.2017YFB1304000)Fundamental Research Funds for the Central Universities,China(No.2232023G-05-1)。
文摘The high-speed winding spindle employs a flexible support system incorporating rubber O-rings.By precisely configuring the structural parameters and the number of the O-rings,the spindle can stably surpass its critical speed points and maintain operational stability across the entire working speed range.However,the support stiffness and damping of rubber O-rings exhibit significant nonlinear frequency dependence.Conventional experimental methods for deriving equivalent stiffness and damping,based on the principle of the forced non-resonance method,require fabricating custom setups for each O-ring specification and conducting vibration tests at varying frequencies,resulting in low efficiency and high costs.This study proposes a hybrid simulation-experimental method for dynamic parameter identification.Firstly,the frequency-dependent dynamic parameters of a specific O-ring support system are experimentally obtained.Subsequently,a corresponding parametric finite element model is established to simulate and solve the equivalent elastic modulus and equivalent stiffness-damping coefficient of this O-ring support system.Ultimately,after iterative simulation,the simulated and experimental results achieve a 99.7%agreement.The parametric finite element model developed herein can directly simulate and inversely estimate frequency-dependent dynamic parameters for O-rings of different specifications but identical elastic modulus.
