Calmodulin （CAM） is involved in the regulation of a variety of cellular signaling pathways. To accomplish its physiological functions, CaM binds with Ca2＋ at its EF-hand Ca2＋ binding sites which induce the conform...Calmodulin （CAM） is involved in the regulation of a variety of cellular signaling pathways. To accomplish its physiological functions, CaM binds with Ca2＋ at its EF-hand Ca2＋ binding sites which induce the conformational switching of CaM. However, the molecular mechanism by which Ca2＋ binds with CaM and induces conformational switching is still obscure. Here we combine molecular dynamics with targeted molecular dynamics simulation and achieve the state-transition pathway of CaM. Our data show that Ca2＋ binding speeds up the conformational transition of CaM by weakening the interactions which stabilize the closed state. It spends about 6.5 ns and 5.25 ns for transition from closed state to open state for apo and holo CaM, respectively. Regarding the contribution of two EF-hands, our data indicate that the first EF-hand triggers the conformational transition and is followed by the second one. We determine that there are two interaction networks which contribute to stabilize the closed and open states, respectively.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 structural changes in the CaO-SiO_(2)-Al_(2)O_(3)-MgO slag system with varying CaO contents were investigated through molecular dynamics(MD)simulations,and its effect on the dissolution behavior of alumina inclusi...The structural changes in the CaO-SiO_(2)-Al_(2)O_(3)-MgO slag system with varying CaO contents were investigated through molecular dynamics(MD)simulations,and its effect on the dissolution behavior of alumina inclusions was characterized by the Kullback-Leibler(KL)divergence.The slag structure analysis revealed that the[AlO]tetrahedral structure was the primary network structure in the slag.With increasing the CaO content,the non-bridge oxygen(NBO)content in the slag structure increases,and the bridge oxygen(BO)content decreases,thereby reducing the complexity of the slag network structure.Raman spectroscopy detection verifies the results of the MD simulations.The results indicated that the dissolution rate of alumina inclusions accelerates with increasing the CaO content in the slag,owing to the reduced complexity of the slag network structure and the enhanced interatomic interactions.The simulation results for the dissolution of alumina inclusions were consistent with theoretical calculations based on the slag inclusion capacity and the dimensionless dissolution rate of inclusions.Radial distribution function analysis demonstrated that the interaction between atoms in the slag system and alumina inclusions strengthens,increasing the dissolution rate of alumina inclusions.The[AlO_(6)]octahedral structure of the alumina inclusions is disrupted,forming BO structures,which in turn enhances the complexity of the slag network structure,slowing the dissolution rate of alumina inclusions.In contrast,the slag system with a higher CaO content has a relatively simpler network structure,promoting faster alumina inclusion dissolution.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
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
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
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
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
Recent advancements in nanotechnology have spotlighted the catalytic potential of nanozymes, particularly single-atom nanozymes(SANs), which are pivotal for innovations in biosensing and medical diagnostics. Among oth...Recent advancements in nanotechnology have spotlighted the catalytic potential of nanozymes, particularly single-atom nanozymes(SANs), which are pivotal for innovations in biosensing and medical diagnostics. Among others, DNA stands out as an ideal biological regulator. Its inherent programmability and interaction capabilities allow it to significantly modulate nanozyme activity. This study delves into the dynamic interplay between DNA and molybdenum-zinc single-atom nanozymes(Mo-Zn SANs). Using molecular dynamics simulations, we uncover how DNA influences the peroxidase-like activities of Mo-Zn SANs, providing a foundational understanding that broadens the application scope of SANs in biosensing.With these insights as a foundation, we developed and demonstrated a model aptasensor for point-ofcare testing(POCT), utilizing a label-free colorimetric approach that leverages DNA-nanozyme interactions to achieve high-sensitivity detection of lysozyme. Our work elucidates the nuanced control DNA exerts over nanozyme functionality and illustrates the application of this molecular mechanism through a smartphone-assisted biosensing platform. This study not only underscores the practical implications of DNA-regulated Mo-Zn SANs in enhancing biosensing platforms, but also highlights the potential of single-atom nanozyme technology to revolutionize diagnostic tools through its inherent versatility and sensitivity.展开更多
A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation...A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation source requires relatively ultrashort electron bunches to produce intense coherent THz pulses.Three electron bunch compression processes are utilized in the PCELL accelerator system comprising pre-bunch compression in an alpha magnet,velocity bunching in a radio-frequency(RF)linear accelerator(linac),and magnetic bunch compression in a 180°acromat system.Electron bunch compression in the magnetic compressor system poses considerable challenges,which are addressed through the use of three quadrupole doublets.The strengths of the quadrupole fields significantly influence the rotation of the beam line longitudinal phase space distribution along the bunch compressor.Start-to-end beam dynamics simulations using the ASTRA code were performed to optimize the electron beam properties for generating super-radiant THz-FEL radiation.The operational parameters considered in the simulations comprise the alpha magnet gradient,linac RF phase,and quadrupole field strengths.The optimization results show that 10-16MeV femtosecond electron bunches with a low energy spread(~0.2%),small normalized emittance(~15πmm·mrad),and high peak current(165-247A)can be produced by the PCELL accelerator system at the optimal parameters.A THz-FEL with sub-microjoule pulse energies can thus be obtained at the optimized electron beam parameters.The physical and conceptual design of the THz-FEL beamline were completed based on the beam dynamics simulation results.The construction and installation of this beamline are currently underway and expected to be completed by mid-2024.The commissioning of the beamline will then commence.展开更多
The kinetic properties of Mg alloy melts are crucial for determining the forming quality of castings,as they directly affect crystal nucleation and dendritic growth.However,accurately assessing the kinetic properties ...The kinetic properties of Mg alloy melts are crucial for determining the forming quality of castings,as they directly affect crystal nucleation and dendritic growth.However,accurately assessing the kinetic properties of molten Mg alloys remains challenging due to the difficulties in experimentally character-izing the high-temperature melts.Herein,we propose that molecular dynamics(MD)simulations driven by deep learning based interatomic potentials(DPs),referred to as DPMD,are a promising strategy to tackle this challenge.We develop MgAl-DP,MgSi-DP,MgCa-DP,and MgZn-DP to assess the kinetic prop-erties of Mg-Al,Mg-Si,Mg-Ca,and Mg-Zn alloy melts.The reliability of our DPs is rigorously evaluated by comparing the DPMD results with those from ab initio MD(AIMD)simulations,as well as available ex-perimental results.Our theoretically evaluated viscosity of Mg-Al melts shows excellent agreement with experimental results over a wide temperature range.Additionally,we found that the solute elements Ca and Zn exhibit sluggish kinetics in the studied melts,which supporting the promising glass-forming abil-ity of the Mg-Zn-Ca alloy system.The computational efficiency of DPMD simulations is several orders of magnitude higher than that of AIMD simulations,while maintaining ab initio-level accuracy.This makes DPMD a highly feasible protocol for building a comprehensive and reliable database of kinetic properties of Mg alloy melts.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
Uranium–molybdenum(U–Mo) alloys are critical for nuclear power generation and propulsion because of their superior thermal conductivity, irradiation stability, and anti-swelling properties. This study explores the p...Uranium–molybdenum(U–Mo) alloys are critical for nuclear power generation and propulsion because of their superior thermal conductivity, irradiation stability, and anti-swelling properties. This study explores the plastic deformation mechanisms of γ-phase U–Mo alloys using molecular dynamics(MD) simulations. In the slip model, the generalized stacking fault energy(GSFE) and the modified Peierls–Nabarro(P–N) model are used to determine the competitive relationships among different slip systems. In the twinning model, the generalized plane fault energy(GPFE) is assessed to evaluate the competition between slip and twinning. The findings reveal that among the three slip systems, the {110}<111>slip system is preferentially activated, while in the {112}<111> system, twinning is favored over slip, as confirmed by MD tensile simulations conducted in various directions. Additionally, the impact of Mo content on deformation behavior is emphasized. Insights are provided for optimizing process conditions to avoid γ → α′′ transitions, thereby maintaining a higher proportion of γ-phase U–Mo alloys for practical applications.展开更多
In the organic Rankine cycle,the refrigerant inevitably interacts with the lubricating oil.This study investigates the interaction mechanism between the fourth-generation refrigerant R1336mzz(Z)and the polyol ester(PO...In the organic Rankine cycle,the refrigerant inevitably interacts with the lubricating oil.This study investigates the interaction mechanism between the fourth-generation refrigerant R1336mzz(Z)and the polyol ester(POE)which is a representative component of the lubricating oil,using molecular dynamics simulations.The research focuses on pentaerythritol ester(PEC)with medium to long chain lengths,specifically PEC9.Relevant parameters such as solubility parameters,diffusion coefficients,binding energies,and radial distribution functions were calculated to elucidate the interaction dynamics.The variation in solubility parameters suggests that the miscibility of PEC9 and R1336mzz(Z)diminishes as the number of PEC9 chains increases.Additionally,the compatibility between these two components deteriorates with rising temperature,which is accompanied by a reduction in their binding energy.The simulation results presented in this study offer theoretical insights into the behavior of refrigerant R1336mzz(Z)upon contact with lubricating oil during actual operation,as well as implications for the operational efficiency of the equipment.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
The experiment explored the Fe_(2)O_(3) reduction process with H_(2)/CO mixed gas and confirmed a promoting effect from CO when its volume proportion in mixed gas is 20% at 850℃.The ReaxFF molecular dynamics(MD)simul...The experiment explored the Fe_(2)O_(3) reduction process with H_(2)/CO mixed gas and confirmed a promoting effect from CO when its volume proportion in mixed gas is 20% at 850℃.The ReaxFF molecular dynamics(MD)simulation method was used to observe the reduction process and provide an atomic-level explanation.The accuracy of the parameters used in the simulation was verified by the density functional theory(DFT)calculation.The simulation shows that the initial reduction rate of H_(2) is much faster than that of CO(from 800 to 950℃).As the reduction proceeds,cementite,obtained after CO participates in the reduction at 850℃,will appear on the iron surface.Due to the active properties of C atoms in cementite,they are easy to further react with the O atoms in Fe_(2)O_(3).The generation of internal CO may destroy the dense structure of the surface layer,thereby affecting the overall reduction swelling of Fe_(2)O_(3).However,excess CO is detrimental to the reaction rate,mainly because of the poor thermodynamic conditions of CO in the temperature range and the molecular diffusion capacity is not as good as that of H_(2).Furthermore,the surface structures obtained after H_(2) and CO reduction have been compared,and it was found that the structure obtained by CO reduction has a larger surface area,thus promoting the sub sequent reaction of H_(2).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 Natural Science Fund for Distinguished Young Scholars of Hebei Province under Grant Nos C2015202340 and C2013202244the Fund for Outstanding Talents of Hebei Province under Grant No C201400305+3 种基金the National Natural Science Fund of China under Grant Nos 11247010,11175055,11475053,11347017,31600594,31400711 and 11647121the Fund for the Science and Technology Program of Higher Education Institutions of Hebei Province under Grant No QN2016113the Scientific Innovation Grant for Excellent Young Scientists of Hebei University of Technology under Grant No 2015010the Natural Science Foundation of Hebei Province under Grant No C2017202208
文摘Calmodulin （CAM） is involved in the regulation of a variety of cellular signaling pathways. To accomplish its physiological functions, CaM binds with Ca2＋ at its EF-hand Ca2＋ binding sites which induce the conformational switching of CaM. However, the molecular mechanism by which Ca2＋ binds with CaM and induces conformational switching is still obscure. Here we combine molecular dynamics with targeted molecular dynamics simulation and achieve the state-transition pathway of CaM. Our data show that Ca2＋ binding speeds up the conformational transition of CaM by weakening the interactions which stabilize the closed state. It spends about 6.5 ns and 5.25 ns for transition from closed state to open state for apo and holo CaM, respectively. Regarding the contribution of two EF-hands, our data indicate that the first EF-hand triggers the conformational transition and is followed by the second one. We determine that there are two interaction networks which contribute to stabilize the closed and open states, respectively.
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supported by Special Funding Projects for Local Science and Technology Development guided by the Central Committee(No.YDZJSX2022C028)the Fundamental Research Program of Shanxi Province(Nos.20210302123218 and 202203021211187)+4 种基金Innovation and Entrepreneurship Training Program for College Students in Shanxi Province(202210109006)the National Natural Science Foundation(52474367)the Key Research and Development for University-Local Government Collaboration of Lvliang City(2024XDHZ01)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2025Q022)the Foundation of State Key Laboratory of Advanced Metallurgy,USTB(K22-10).
文摘The structural changes in the CaO-SiO_(2)-Al_(2)O_(3)-MgO slag system with varying CaO contents were investigated through molecular dynamics(MD)simulations,and its effect on the dissolution behavior of alumina inclusions was characterized by the Kullback-Leibler(KL)divergence.The slag structure analysis revealed that the[AlO]tetrahedral structure was the primary network structure in the slag.With increasing the CaO content,the non-bridge oxygen(NBO)content in the slag structure increases,and the bridge oxygen(BO)content decreases,thereby reducing the complexity of the slag network structure.Raman spectroscopy detection verifies the results of the MD simulations.The results indicated that the dissolution rate of alumina inclusions accelerates with increasing the CaO content in the slag,owing to the reduced complexity of the slag network structure and the enhanced interatomic interactions.The simulation results for the dissolution of alumina inclusions were consistent with theoretical calculations based on the slag inclusion capacity and the dimensionless dissolution rate of inclusions.Radial distribution function analysis demonstrated that the interaction between atoms in the slag system and alumina inclusions strengthens,increasing the dissolution rate of alumina inclusions.The[AlO_(6)]octahedral structure of the alumina inclusions is disrupted,forming BO structures,which in turn enhances the complexity of the slag network structure,slowing the dissolution rate of alumina inclusions.In contrast,the slag system with a higher CaO content has a relatively simpler network structure,promoting faster alumina inclusion dissolution.
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supported by the Science and Technology Research Project from Education Department of Jilin Province (No. JJKH20231296KJ)the Natural Science Foundation of Science and Technology Department of Jilin Province (Joint Fund Project) (No. YDZJ202201ZYTS340)+9 种基金the Fundamental Research Funds for the Central Universities (No. 2412022ZD013)the Science and Technology Development Plan Project of Jilin Province (Nos. SKL202302030, SKL202402017, 20210204126YY, 20230204113YY, 20240602003RC, 20210402059GH)the National Natural Science Foundation of China (Nos. 22174137, 22322410, 92372102 and 22073094)the Cooperation Funding of Changchun with Chinese Academy of Sciences (No. 22SH13)the Capital Construction Fund Projects within the Budget of Jilin Province (No. 2023C042–5)the University Level Scientific Research Projects of Ordinary Universities in Xinjiang Uygur Autonomous Region (No. 2022YQSN002)the State Key Laboratory of Molecular Engineering of Polymers (Fudan University) (No. K2024–11)the Program for Young Scholars in Regional Development of CASthe essential support of the Network and Computing Center, CIAC, CASthe Computing Center of Jilin Province。
文摘Recent advancements in nanotechnology have spotlighted the catalytic potential of nanozymes, particularly single-atom nanozymes(SANs), which are pivotal for innovations in biosensing and medical diagnostics. Among others, DNA stands out as an ideal biological regulator. Its inherent programmability and interaction capabilities allow it to significantly modulate nanozyme activity. This study delves into the dynamic interplay between DNA and molybdenum-zinc single-atom nanozymes(Mo-Zn SANs). Using molecular dynamics simulations, we uncover how DNA influences the peroxidase-like activities of Mo-Zn SANs, providing a foundational understanding that broadens the application scope of SANs in biosensing.With these insights as a foundation, we developed and demonstrated a model aptasensor for point-ofcare testing(POCT), utilizing a label-free colorimetric approach that leverages DNA-nanozyme interactions to achieve high-sensitivity detection of lysozyme. Our work elucidates the nuanced control DNA exerts over nanozyme functionality and illustrates the application of this molecular mechanism through a smartphone-assisted biosensing platform. This study not only underscores the practical implications of DNA-regulated Mo-Zn SANs in enhancing biosensing platforms, but also highlights the potential of single-atom nanozyme technology to revolutionize diagnostic tools through its inherent versatility and sensitivity.
基金support from the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research,and Innovation(No.B05F650022),as well as from Chiang Mai University.
文摘A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation source requires relatively ultrashort electron bunches to produce intense coherent THz pulses.Three electron bunch compression processes are utilized in the PCELL accelerator system comprising pre-bunch compression in an alpha magnet,velocity bunching in a radio-frequency(RF)linear accelerator(linac),and magnetic bunch compression in a 180°acromat system.Electron bunch compression in the magnetic compressor system poses considerable challenges,which are addressed through the use of three quadrupole doublets.The strengths of the quadrupole fields significantly influence the rotation of the beam line longitudinal phase space distribution along the bunch compressor.Start-to-end beam dynamics simulations using the ASTRA code were performed to optimize the electron beam properties for generating super-radiant THz-FEL radiation.The operational parameters considered in the simulations comprise the alpha magnet gradient,linac RF phase,and quadrupole field strengths.The optimization results show that 10-16MeV femtosecond electron bunches with a low energy spread(~0.2%),small normalized emittance(~15πmm·mrad),and high peak current(165-247A)can be produced by the PCELL accelerator system at the optimal parameters.A THz-FEL with sub-microjoule pulse energies can thus be obtained at the optimized electron beam parameters.The physical and conceptual design of the THz-FEL beamline were completed based on the beam dynamics simulation results.The construction and installation of this beamline are currently underway and expected to be completed by mid-2024.The commissioning of the beamline will then commence.
基金Financial support from the National Natural Science Founda-tion of China(Nos.52222409 and52074132)the National Key Research and Development Program(No.2022YFE0122000)+1 种基金Partial financial support comes from the Science and Technology Development Program of Jilin Province(No.20210301025GX)the Fundamental Research Funds for the Central Universities,JLU.
文摘The kinetic properties of Mg alloy melts are crucial for determining the forming quality of castings,as they directly affect crystal nucleation and dendritic growth.However,accurately assessing the kinetic properties of molten Mg alloys remains challenging due to the difficulties in experimentally character-izing the high-temperature melts.Herein,we propose that molecular dynamics(MD)simulations driven by deep learning based interatomic potentials(DPs),referred to as DPMD,are a promising strategy to tackle this challenge.We develop MgAl-DP,MgSi-DP,MgCa-DP,and MgZn-DP to assess the kinetic prop-erties of Mg-Al,Mg-Si,Mg-Ca,and Mg-Zn alloy melts.The reliability of our DPs is rigorously evaluated by comparing the DPMD results with those from ab initio MD(AIMD)simulations,as well as available ex-perimental results.Our theoretically evaluated viscosity of Mg-Al melts shows excellent agreement with experimental results over a wide temperature range.Additionally,we found that the solute elements Ca and Zn exhibit sluggish kinetics in the studied melts,which supporting the promising glass-forming abil-ity of the Mg-Zn-Ca alloy system.The computational efficiency of DPMD simulations is several orders of magnitude higher than that of AIMD simulations,while maintaining ab initio-level accuracy.This makes DPMD a highly feasible protocol for building a comprehensive and reliable database of kinetic properties of Mg alloy melts.
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Project supported by the National Natural Science Foundation of China (Grant No. 52271105)。
文摘Uranium–molybdenum(U–Mo) alloys are critical for nuclear power generation and propulsion because of their superior thermal conductivity, irradiation stability, and anti-swelling properties. This study explores the plastic deformation mechanisms of γ-phase U–Mo alloys using molecular dynamics(MD) simulations. In the slip model, the generalized stacking fault energy(GSFE) and the modified Peierls–Nabarro(P–N) model are used to determine the competitive relationships among different slip systems. In the twinning model, the generalized plane fault energy(GPFE) is assessed to evaluate the competition between slip and twinning. The findings reveal that among the three slip systems, the {110}<111>slip system is preferentially activated, while in the {112}<111> system, twinning is favored over slip, as confirmed by MD tensile simulations conducted in various directions. Additionally, the impact of Mo content on deformation behavior is emphasized. Insights are provided for optimizing process conditions to avoid γ → α′′ transitions, thereby maintaining a higher proportion of γ-phase U–Mo alloys for practical applications.
基金supported by Hainan Provincial Natural Science Foundation of China(No.422CXTD509).
文摘In the organic Rankine cycle,the refrigerant inevitably interacts with the lubricating oil.This study investigates the interaction mechanism between the fourth-generation refrigerant R1336mzz(Z)and the polyol ester(POE)which is a representative component of the lubricating oil,using molecular dynamics simulations.The research focuses on pentaerythritol ester(PEC)with medium to long chain lengths,specifically PEC9.Relevant parameters such as solubility parameters,diffusion coefficients,binding energies,and radial distribution functions were calculated to elucidate the interaction dynamics.The variation in solubility parameters suggests that the miscibility of PEC9 and R1336mzz(Z)diminishes as the number of PEC9 chains increases.Additionally,the compatibility between these two components deteriorates with rising temperature,which is accompanied by a reduction in their binding energy.The simulation results presented in this study offer theoretical insights into the behavior of refrigerant R1336mzz(Z)upon contact with lubricating oil during actual operation,as well as implications for the operational efficiency of the equipment.
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financial support from the National Natural Science Foundation of China(Nos.52204335 and 52374319)the National Nature Science Foundation of China(No.52174291)the Central Universities Foundation of China(No.06500170)。
文摘The experiment explored the Fe_(2)O_(3) reduction process with H_(2)/CO mixed gas and confirmed a promoting effect from CO when its volume proportion in mixed gas is 20% at 850℃.The ReaxFF molecular dynamics(MD)simulation method was used to observe the reduction process and provide an atomic-level explanation.The accuracy of the parameters used in the simulation was verified by the density functional theory(DFT)calculation.The simulation shows that the initial reduction rate of H_(2) is much faster than that of CO(from 800 to 950℃).As the reduction proceeds,cementite,obtained after CO participates in the reduction at 850℃,will appear on the iron surface.Due to the active properties of C atoms in cementite,they are easy to further react with the O atoms in Fe_(2)O_(3).The generation of internal CO may destroy the dense structure of the surface layer,thereby affecting the overall reduction swelling of Fe_(2)O_(3).However,excess CO is detrimental to the reaction rate,mainly because of the poor thermodynamic conditions of CO in the temperature range and the molecular diffusion capacity is not as good as that of H_(2).Furthermore,the surface structures obtained after H_(2) and CO reduction have been compared,and it was found that the structure obtained by CO reduction has a larger surface area,thus promoting the sub sequent reaction of H_(2).
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.
