Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer ...Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding.The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction(EBSD).A methodology combining finite element method-smoothed particle hydrodynamics(FEM-SPH)and molecular dynamics(MD)was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale.The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration,without discernible defects or cracks.The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces.Furthermore,the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer.The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results.MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase,and the simulated thickness of interfacial diffusion aligns well with experimental outcomes.The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates.Furthermore,this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.展开更多
The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggre...The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggregate was analyzed by molecular dynamics simulation.The diffusion coefficient and concentration distribution of SBS modified asphalt on aggregate surface are included.The simulation results show that the diffusion coefficient of the aggregate surface of SBS modified asphalt is increased by 47.6%and 70.5%respectively after 110#asphalt and 130#asphalt are pre-wetted.The concentration distribution of SBS modified asphalt on the aggregate surface after pre-wetting is more uniform.According to the results of interface energy calculation,the interface energy of SBS modified bitumen and aggregate can be increased by about 5%after pre-wetting.According to the results of molecular dynamics simulation,the pre-wetting technology can effectively improve the interface workability of SBS modified bitumen and aggregate,so as to improve the interface performance.展开更多
The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structu...The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structural integrity of steel gas pipelines that uses advanced numerical modeling techniques to anticipate fracture development and corrosion effects.The objective is to increase pipeline dependability and safety through more precise,real-time health evaluations.Compared to previous approaches,our solution provides higher accuracy in fault detection and quantification,making it ideal for pipeline integritymonitoring in real-world applications.To solve this issue,statistical analysis was conducted on the size and directional distribution features of about 380,000 sets of internal corrosion faults,as well as simulations of erosion and wear patterns on bent pipes.Using real defectmorphologies,we developed a modeling framework for typical interior corrosion flaws.We evaluated and validated the applicability and effectiveness of in-service inspection processes,as well as conducted on-site comparison tests.The results show that(1)the length and width of corrosion defects follow a log-normal distribution,the clock orientation follows a normal distribution,and the peak depth follows a Freundlich EX function distribution pattern;(2)pipeline corrosion defect data can be classified into three classes using the K-means clustering algorithm,allowing rapid and convenient acquisition of typical size and orientation characteristics of internal corrosion defects;(3)the applicability range and boundary conditions of various NDT techniques were verified,establishing comprehensive selection principles for internal corrosion defect detection technology;(4)on-site inspection results showed a 31%The simulation and validation platform for typical interior corrosion issues greatly enhances the accuracy and reliability of detection data.展开更多
Objective:To gain insight into the potential factors that may cause perceived stress and anxiety in simulation education.Methods:A secondary qualitative analysis study using qualitative thematic synthesis.A local high...Objective:To gain insight into the potential factors that may cause perceived stress and anxiety in simulation education.Methods:A secondary qualitative analysis study using qualitative thematic synthesis.A local higher education institution that conducted pre-registration nursing programs.A total of 189 undergraduate nursing students that were never attained any clinical placement prior to the parent study.Focus group interviews were conducted to collect data that were then transcribed and analyzed through the qualitative thematic synthesis approach to develop themes.Results:Three themes were emerged from the participants’simulation experiences in terms of peoples(the observers vs the observed),actions(the prepared vs the unprepared),and settings(the realism vs the simulation).Conclusions:By considering and reviewing the current design and development of the simulation practice,the findings of this study contribute to the body of knowledge with valuable insights on stress and anxiety that may affect students’learning in simulation.展开更多
Grouting has been the most effective approach to mitigate water inrush disasters in underground engineering due to its ability to plug groundwater and enhance rock strength.Nevertheless,there is a lack of potent numer...Grouting has been the most effective approach to mitigate water inrush disasters in underground engineering due to its ability to plug groundwater and enhance rock strength.Nevertheless,there is a lack of potent numerical tools for assessing the grouting effectiveness in water-rich fractured strata.In this study,the hydro-mechanical coupled discontinuous deformation analysis(HM-DDA)is inaugurally extended to simulate the grouting process in a water-rich discrete fracture network(DFN),including the slurry migration,fracture dilation,water plugging in a seepage field,and joint reinforcement after coagulation.To validate the capabilities of the developed method,several numerical examples are conducted incorporating the Newtonian fluid and Bingham slurry.The simulation results closely align with the analytical solutions.Additionally,a set of compression tests is conducted on the fresh and grouted rock specimens to verify the reinforcement method and calibrate the rational properties of reinforced joints.An engineering-scale model based on a real water inrush case of the Yonglian tunnel in a water-rich fractured zone has been established.The model demonstrates the effectiveness of grouting reinforcement in mitigating water inrush disaster.The results indicate that increased grouting pressure greatly affects the regulation of water outflow from the tunnel face and the prevention of rock detachment face after excavation.展开更多
Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing ...Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing a greater role in the performance of components. This paper investigates the effect of heat treatment on residual stresses induced in AISI 1025, manufactured using LENS. Finite element model was developed and simulated to analyze residual stress development. AISI 1025 samples suitable for tool and die applications in Fused Deposition Modelling (FDM) filament production, were fabricated using Laser Engineered Net Shaping (LENS) process, followed by heat treatment where annealing and quenching processes were done. The material’s microstructure, residual stress and hardness of heat-treated samples under investigation, were compared against the as-built samples. The results indicated that after annealing, tensile residual stresses were reduced by 93%, resulting in a reduced crack growth rate, compared to the as-built sample, although the hardness was reduced significantly by 25%. On the other hand, high tensile residual stresses of 425 ± 14 MPa were recorded after quenching process with an improvement of hardness by 21%.展开更多
Highly energy-efficient buildings have generated remarkable interest over the last few years.There is a need for simulation based effective control systems for efficient usage of electrical and fossil fuel driven devi...Highly energy-efficient buildings have generated remarkable interest over the last few years.There is a need for simulation based effective control systems for efficient usage of electrical and fossil fuel driven devices,as they contribute to energy-efficient buildings and assist in gaining flexibility for the human occupancy-based energy loads.In this context,the integrated energy profile of a building can be ascertained by effective research approaches,as this knowledge would be beneficial to understand the demographics with respect to human occupancy and activities,as well as estimate varying energy consumption over time.Utility data from Smart Meter(SM)readings can reveal detailed information that could be mapped to predict resident occupancy and the usage patterns of specific types of appliances over desired time intervals.This research develops a user-driven simulation tool with realistic data acquisition options and assumptions of potential human behavior to determine energy usage patterns over time without the utility billing information.In this work,factors such as level of human occupancy,the possibility of space being occupied,thermostat settings,building envelope infrastructural aspects,types of appliances used in households,appliance energy related capacities,and the probability of using each appliance is considered,along with variance in weather,and heating-cooling systems specifications.For five specific benchmarked scenarios,the range of the random numbers is specified based on assumed potential human behavior for occupancy and energy-consuming appliances usage probabilities,with respect to the time of the day,weekday,and weekends.The simulation is developed using the Visual Basic Application(VBA)^(R)in Microsoft Excel^(R),based on the discrete-event Monte Carlo Simulation(MCS).The simulated energy usage and the cost are reflected in the sensitivity analysis by comparing factors such as the level of human occupancy,appliance type,and time intervals.展开更多
The aim of this study is to address the issues associated with traditional magnetorheological fluid(MRF)dampers,such as insufficient damping force after power failure and susceptibility to settlement.In order to achie...The aim of this study is to address the issues associated with traditional magnetorheological fluid(MRF)dampers,such as insufficient damping force after power failure and susceptibility to settlement.In order to achieve this,a bidirectional adjustable MRF damper was designed and developed.Magnetic field simulation analysis was conducted on the damper,along with simulation analysis on its dynamic characteristics.The dynamic characteristics were ultimately validated through experimental testing on the material testing machine,thereby corroborating the theoretical simulation results.Concurrently,this process generated valuable test data for subsequent implementation of the semi-active vibration control system.The simulation and test results demonstrate that the integrated permanent magnet effectively accomplishes bidirectional regulation.The magnetic induction intensity of the damping channel is 0.2 T in the absence of current,increases to 0.5 T when a maximum forward current of 4 A is applied,and becomes 0 T when a maximum reverse current of 3.8 A is applied.When the excitation amplitude is 8 mm and the frequency is 2 Hz,with the applied currents varying,the maximum damping force reaches 8 kN,while the minimum damping force measures at 511 N.Additionally,at zero current,the damping force stands at 2 kN,which aligns closely with simulation results.The present paper can serve as a valuable reference for the design and research of semi-active MRF dampers.展开更多
The utilization of multi-field coupling simulation methods has become a pivotal approach for the investigation of intricate fracture behavior and interaction mechanisms of rock masses in deep strata.The high temperatu...The utilization of multi-field coupling simulation methods has become a pivotal approach for the investigation of intricate fracture behavior and interaction mechanisms of rock masses in deep strata.The high temperatures,pressures and complex geological environments of deep strata frequently result in the coupling of multiple physical fields,including mechanical,thermal and hydraulic fields,during the fracturing of rocks.This review initially presents an overview of the coupling mechanisms of these physical fields,thereby elucidating the interaction processes ofmechanical,thermal,and hydraulic fields within rockmasses.Secondly,an in-depth analysis ofmulti-field coupling is conducted from both spatial and temporal perspectives,with the introduction of simulation methods for a range of scales.It emphasizes cross-scale coupling methodologies for the transfer of rock properties and physical field data,including homogenization techniques,nested coupling strategies and data-driven approaches.To address the discontinuous characteristics of the rock fracture process,the review provides a detailed explanation of continuousdiscontinuous couplingmethods,to elucidate the evolution of rock fracturing and deformationmore comprehensively.In conclusion,the review presents a summary of the principal points,challenges and future directions of multi-field coupling simulation research.It also puts forward the potential of integrating intelligent algorithms with multi-scale simulation techniques to enhance the accuracy and efficiency of multi-field coupling simulations.This offers novel insights into multi-field coupling simulation analysis in deep rock masses.展开更多
The coupling between heat and pressure is the kernel of inertia friction welding(IFW)and is still not fully understood.A novel 3D fully coupled finite element model based on a plastic friction pair was developed to si...The coupling between heat and pressure is the kernel of inertia friction welding(IFW)and is still not fully understood.A novel 3D fully coupled finite element model based on a plastic friction pair was developed to simulate the IFW process of a Ni-based superalloy and reveal the omnidirectional thermo-mechanical coupling mechanism of the friction interface.The numerical model successfully simulated the deceleration,deformation processes,and peak torsional moments in IFW and captured the evolution of temperature,contact pressure,and stress.The simulated results were validated through measured thermal history,optical macrography,and axial shortening.The results indicated that interfacial friction heat was the primary heat source,and plastic deformation energy only accounted for 4%of the total.The increase in initial rotational speed and friction pressure elevated the peak temperature,reaching a maximum of 1525.5K at an initial rotational speed of 2000 r/min and friction pressure of 400 MPa.The interface heat generation could form an axial temperature gradient exceeding 320K/mm.The radial inhomogeneities of heat generation and temperature were manifested in a concentric ring distribution with maximum heat flux and temperature ranging from 2/5 to 2/3 radius.The radial inhomogeneities were caused by increasing linear velocity along the radius and an opposite distribution of contact pressure,which could reach 1.7 times the set pressure at the center.The circumferential inhomogeneity of thermomechanical distribution during rotary friction welding was revealed for the first time,benefiting from the 3D model.The deflection and transformation of distribution in contact pressure and Mises stress were indicators of plastic deformation and transition of quasi-steady state welding.The critical Mises stress was 0.5 times the friction pressure in this study.The presented modeling provides a reliable insight into the thermo-mechanical coupling mechanism of IFW and lays a solid foundation for predicting the microstructures and mechanical properties of inertia friction welded joints.展开更多
Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production eff...Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production efficiency of shale oil resources.Effectively stimulating oil shale reservoirs remains a challenging and active research topic.This investigation employed shale specimens obtained from the Longmaxi Formation.Scanning electron microscopy,fluid injection experiments,and fluid-structure interaction simulations were used to comprehensively analyze structural changes and fluid flow behavior under high temperatures from microscopic to macroscopic scales.Experimental results indicate that the temperature has little effect on the structure and permeability of shale before 300℃.However,there are two threshold temperatures within the range of 300 to 600℃that have significant effects on the structure and permeability of oil shale.The first threshold temperature is between 300 and 400℃,which causes the oil shale porosity,pore-fracture ratio,and permeability begin to increase.This is manifested by the decrease in micropores and mesopores,the increase in macropores,and the formation of a large number of isolated pores and fissures within the shale.The permeability increases but not significantly.The second threshold temperature is between 500 and 600℃,which increases the permeability of oil shale significantly.During this stage,micropores and mesopores are further reduced,and macropores are significantly enlarged.A large number of connected and penetrated pores and fissures are formed.More numerous and thicker streamlines appear inside the oil shale.The experimental results demonstrate that high temperatures significantly alter the microstructure and permeability of oil shale.At the same time,the experimental results can provide a reference for the research of in-situ heating techniques in oil shale reservoir transformation.展开更多
The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electr...The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electrothermal de-icing seldom delve into comprehensive ice accretion-melting-deicing models that account for ice shedding.Therefore,the detachment behavior of ice layers during the heating process requires in-depth research and discussion.This paper physically models the phenomenon of ice shedding,incorporates the detachment behavior of ice layers during heating,improves the existing mathematical model for electro-thermal de-icing calculations,establishes an ice accretion-melting-deicing model for electro-thermal de-icing systems,and conducts numerical simulation,verification and optimization analysis of electro-thermal de-icing considering ice shedding.Through multi-condition de-icing numerical simulations of a specific wing model,it is found that ambient temperature can serve as a factor for adapting the electro heating anti/de-icing strategy to the environment.An optimization of heating heat flux density and heating/cooling time is conducted for the wing de-icing control law under the calculated conditions.The improved electrothermal de-icing model and algorithm developed in this paper provide solid technical support for the design of electrothermal de-icing systems.展开更多
This study employs Principal Component Analysis(PCA)and 13 years of SD-WACCM-X model data(2007-2019)to investigate the characteristics and mechanisms of Inter-hemispheric Coupling(IHC)triggered by sudden stratospheric...This study employs Principal Component Analysis(PCA)and 13 years of SD-WACCM-X model data(2007-2019)to investigate the characteristics and mechanisms of Inter-hemispheric Coupling(IHC)triggered by sudden stratospheric warming(SSW)events.IHC in both hemispheres leads to a cold anomaly in the equatorial stratosphere,a warm anomaly in the equatorial mesosphere,and increased temperatures in the mesosphere and lower thermosphere(MLT)region of the summer hemisphere.However,the IHC features during boreal winter period are significantly weaker than during the austral winter period,primarily due to weaker stationary planetary wave activity in the Southern Hemisphere(SH).During the austral winter period,IHC results in a warm anomaly in the polar mesosphere of the SH,which does not occur in the NH during boreal winter period.This study also examines the possible influence of quasi-two-day waves(QTDWs)on IHC.We found that the largest temperature anomaly in the summer polar MLT region is associated with a large wind instability area,and a well-developed critical layer structure of QTDW in January.In contrast,during July,despite favorable conditions for QTDW propagation in the Northern Hemisphere,weaker IHC response is observed,suggesting that IHC features and the relationship with QTDWs during July would be more complex than during January.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
The micro-area characterization experiments like scanning Kelvin probe force microscope(SKPFM)and Kernel average misorientation have the defects of complex sample preparation and occasional errors in test results,whic...The micro-area characterization experiments like scanning Kelvin probe force microscope(SKPFM)and Kernel average misorientation have the defects of complex sample preparation and occasional errors in test results,which makes it impossible to accurately and quickly analyze the pitting behavior induced by inclusions in some cases,prompting attempts to turn to simulation calculation research.The method of calculating band structure and work function can be used to replace current-sensing atomic force microscopy and SKPFM to detect the potential and conductivity of the sample.The band structure results show that Al_(2)O_(3) inclusion is an insulator and non-conductive,and it will not form galvanic corrosion with the matrix.Al_(2)O_(3) inclusion does not dissolve because its work function is higher than that of the matrix.Moreover,the stress concentration of the matrix around the inclusion can be characterized by first-principles calculation coupled with finite element simulation.The results show that the stress concentration degree of the matrix around Al_(2)O_(3) inclusion is serious,and the galvanic corrosion is formed between the high and the low stress concentration areas,which can be used to explain the reason of the pitting induced by Al_(2)O_(3) inclusions.展开更多
Flat-panel X-ray sources(FPXSs)have many advantages in terms of compactness and low-dose imaging,enhancing their capability for novel X-ray applications.Experimental analysis of the X-ray characteristics and optimizin...Flat-panel X-ray sources(FPXSs)have many advantages in terms of compactness and low-dose imaging,enhancing their capability for novel X-ray applications.Experimental analysis of the X-ray characteristics and optimizing the anode panel of an FPXS are time-consuming,expensive,and sometimes impractical.In this study,a FPXS was prepared using a ZnO nanowire cold cathode and a molybdenum film anode target.Monte Carlo(MC)simulations were utilized to optimize the anode panel and obtain the average fluence,average energy,and spatial distribution of the X-rays for the ZnO nanowire FPXS.The accuracy of the MC simulations was verified by comparing the measured and simulated energy spectra.Optimization of the anode target considers the material,thickness,and morphology,whereas optimization of the substrate focuses on the material and thickness.The results show that the difference between the positions of the K-shell peaks in the measured and simulated energy spectra is within 0.26 keV.At the acceleration voltages of 30 kV,60 kV,and 90 kV,the optimal thicknesses of the tungsten array anode were 0.65μm,2.45μm,and 5μm,respectively,while the molybdenum array anode has the optimal thicknesses of 1.45μm,5.25μm,and 24μm,respectively.The microsemi-ellipsoidal anode with a recessed design showed a 5%increase in the transmitted X-ray fluence compared with the film target.The sapphire substrate with a thickness of 0.78 mm exhibits a mechanical strength comparable to that of a glass substrate with a thickness of 3 mm,implying that the former can increase the average X-ray fluence by reducing the filtration of X-rays.The findings of this study provide valuable guidance for the fabrication and optimization of the ZnO nanowire FPXS.展开更多
Actuator dynamics introduce a synchronization disparity between commanded displacements transmitted to the actuator and the actual displacements generated by the actuator,thereby affecting its precision and potentiall...Actuator dynamics introduce a synchronization disparity between commanded displacements transmitted to the actuator and the actual displacements generated by the actuator,thereby affecting its precision and potentially leading to instability in real-time hybrid simulation(RTHS).This study aims to elucidate the relationship between calculated and measured displacements by analyzing their magnitude and phase in the frequency domain via transformations.The physical implications of these relationships are explored in the context of frequency domain evaluation indices(FEI),the transfer function of actuator dynamics,and delay compensation.Formulations for achieving perfect compensation of actuator dynamics are developed,and an enhanced compensation approach,termed improved windowed frequency domain evaluation index-based compensation(IWFEI),is introduced.The efficacy of IWFEI is assessed using a RTHS benchmark model,with perturbed simulations conducted to validate its robustness.Uncertainties inherent in actuator dynamics are represented as random variables in these simulations.Comparative analysis of the mean values and variances of evaluation criteria demonstrates that IWFEI enables more accurate and robust compensation.Furthermore,strong correlations observed among criteria in the time and frequency domains underscore the effectiveness of the proposed frequency domain-based compensation method in mitigating amplitude errors and phase delays in RTHS.展开更多
In recent years,rapid urbanization has had a profound impact on landscape stability.As a typical example of China's rapid urbanization,Hangzhou has also experienced significant landscape changes,which have profoun...In recent years,rapid urbanization has had a profound impact on landscape stability.As a typical example of China's rapid urbanization,Hangzhou has also experienced significant landscape changes,which have profoundly affected its ecological stability.Taking Hangzhou as an example,this study integrates land use change data from 1980 to 2020,combines dynamic simulation and ecological modeling techniques,and carries out a comprehensive analysis of historical trends and future predictions,to provide valuable insights into the complex interactions between urban expansion and landscape stability.The results indicate that:1)between 1980 and2020,Hangzhou experienced a significant increase in construction land at the expense of arable land,leading to a gradual decline in landscape stability,though the downward trend has slowed in recent years.2)The spatial distribution of landscape stability shows clear aggregation patterns,with lower stability concentrated in economically active flatlands and higher stability in the mountainous western regions.3)By 2040,further urban expansion is predicted to occur alongside increased landscape integration,reflecting the positive effects of ecological protection strategies.This study highlights the universal challenges of balancing economic growth with ecological stability in rapidly urbanizing regions.The combination of advanced simulation models and spatiotemporal analysis demonstrates a replicable framework for assessing urban expansion's ecological impacts.These findings underscore the importance of tailoring urban planning and ecological policies to address regional disparities,providing valuable insights for sustainable urban development and landscape management globally.展开更多
Due to uncertainties in seismic pipeline damage and post-earthquake recovery processes,probabilistic characteristics such as mean value,standard deviation,probability density function,and cumulative distribution funct...Due to uncertainties in seismic pipeline damage and post-earthquake recovery processes,probabilistic characteristics such as mean value,standard deviation,probability density function,and cumulative distribution function provide valuable information.In this study,a simulation-based framework to evaluate these probabilistic characteristics in water distribution systems(WDSs)during post-earthquake recovery is developed.The framework first calculates pipeline failure probabilities using seismic fragility models and then generates damage samples through quasi-Monte Carlo simulations with Sobol’s sequence for faster convergence.System performance is assessed using a hydraulic model,and recovery simulations produce time-varying performance curves,where the dynamic importance of unrepaired damage determines repair sequences.Finally,the probabilistic characteristics of seismic performance indicators,resilience index,resilience loss,and recovery time are evaluated.The framework is applied in two benchmark WDSs with different layouts to investigate the probabilistic characteristics of their seismic performance and resilience.Application results show that the cumulative distribution function reveals the variations in resilience indicators for different exceedance probabilities,and there are dramatic differences among the recovery times corresponding to the system performance recovery targets of 80%,90%,and 100%.展开更多
Algal copper uptake(i.e.,Cu bioavailability)in the euphotic zone plays a vital role in algal photosynthesis and respiration,affecting the primary productivity and the source and sink of atmospheric carbon.Algal Cu upt...Algal copper uptake(i.e.,Cu bioavailability)in the euphotic zone plays a vital role in algal photosynthesis and respiration,affecting the primary productivity and the source and sink of atmospheric carbon.Algal Cu uptake is controlled by natural dissolved organic Cu(DOCu)speciation(i.e.,complexed with the dissolved organic matter)that conventionally could be tested by model prediction or molecular-level characterizations in the lab,while DOCu uptake are hardly directly assessed.Thus,the new chemistrybiology insight into the mechanisms of the Cu uptake process in algae is urgent.The DOCu speciation transformation(organic DOCu to free Cu(II)ions),enzymatic reduction-induced valence change(reduction of free Cu(II)to Cu(I)ions),and algal Cu uptake at the algae-water interface are imitated.Herein,an intelligent system with DOCu colorimetric sensor is developed for real-time monitoring of newly generated Cu(I)ions.Deep learning with whole sample image-based characterization and powerful feature extraction capabilities facilitates colorimetric measurement.In this context,the Cu bioavailability with 7 kinds of organic ligands(e.g.,amino acids,organic acids,carbohydrates)can be predicted by the mimetic intelligent biosensor within 15.0min,i.e.,the DOCu uptake and speciation is successfully predicted and streamlined by the biomimetic approach.展开更多
基金Opening Foundation of Key Laboratory of Explosive Energy Utilization and Control,Anhui Province(BP20240104)Graduate Innovation Program of China University of Mining and Technology(2024WLJCRCZL049)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_2701)。
文摘Because of the challenge of compounding lightweight,high-strength Ti/Al alloys due to their considerable disparity in properties,Al 6063 as intermediate layer was proposed to fabricate TC4/Al 6063/Al 7075 three-layer composite plate by explosive welding.The microscopic properties of each bonding interface were elucidated through field emission scanning electron microscope and electron backscattered diffraction(EBSD).A methodology combining finite element method-smoothed particle hydrodynamics(FEM-SPH)and molecular dynamics(MD)was proposed for the analysis of the forming and evolution characteristics of explosive welding interfaces at multi-scale.The results demonstrate that the bonding interface morphologies of TC4/Al 6063 and Al 6063/Al 7075 exhibit a flat and wavy configuration,without discernible defects or cracks.The phenomenon of grain refinement is observed in the vicinity of the two bonding interfaces.Furthermore,the degree of plastic deformation of TC4 and Al 7075 is more pronounced than that of Al 6063 in the intermediate layer.The interface morphology characteristics obtained by FEM-SPH simulation exhibit a high degree of similarity to the experimental results.MD simulations reveal that the diffusion of interfacial elements predominantly occurs during the unloading phase,and the simulated thickness of interfacial diffusion aligns well with experimental outcomes.The introduction of intermediate layer in the explosive welding process can effectively produce high-quality titanium/aluminum alloy composite plates.Furthermore,this approach offers a multi-scale simulation strategy for the study of explosive welding bonding interfaces.
基金Funded by the Research Funds of China University of Mining and Technology(No.102523215)。
文摘The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggregate was analyzed by molecular dynamics simulation.The diffusion coefficient and concentration distribution of SBS modified asphalt on aggregate surface are included.The simulation results show that the diffusion coefficient of the aggregate surface of SBS modified asphalt is increased by 47.6%and 70.5%respectively after 110#asphalt and 130#asphalt are pre-wetted.The concentration distribution of SBS modified asphalt on the aggregate surface after pre-wetting is more uniform.According to the results of interface energy calculation,the interface energy of SBS modified bitumen and aggregate can be increased by about 5%after pre-wetting.According to the results of molecular dynamics simulation,the pre-wetting technology can effectively improve the interface workability of SBS modified bitumen and aggregate,so as to improve the interface performance.
基金The“13th Five-Year Plan”National Science and Technology Major Project,2016ZX05052,Changchao QiThe China National Petroleum Corporation Science and Technology Project,2021DJ6505,Changchao Qi.
文摘The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structural integrity of steel gas pipelines that uses advanced numerical modeling techniques to anticipate fracture development and corrosion effects.The objective is to increase pipeline dependability and safety through more precise,real-time health evaluations.Compared to previous approaches,our solution provides higher accuracy in fault detection and quantification,making it ideal for pipeline integritymonitoring in real-world applications.To solve this issue,statistical analysis was conducted on the size and directional distribution features of about 380,000 sets of internal corrosion faults,as well as simulations of erosion and wear patterns on bent pipes.Using real defectmorphologies,we developed a modeling framework for typical interior corrosion flaws.We evaluated and validated the applicability and effectiveness of in-service inspection processes,as well as conducted on-site comparison tests.The results show that(1)the length and width of corrosion defects follow a log-normal distribution,the clock orientation follows a normal distribution,and the peak depth follows a Freundlich EX function distribution pattern;(2)pipeline corrosion defect data can be classified into three classes using the K-means clustering algorithm,allowing rapid and convenient acquisition of typical size and orientation characteristics of internal corrosion defects;(3)the applicability range and boundary conditions of various NDT techniques were verified,establishing comprehensive selection principles for internal corrosion defect detection technology;(4)on-site inspection results showed a 31%The simulation and validation platform for typical interior corrosion issues greatly enhances the accuracy and reliability of detection data.
基金supported by School Research Grant of Tung Wah College(SRG210401).
文摘Objective:To gain insight into the potential factors that may cause perceived stress and anxiety in simulation education.Methods:A secondary qualitative analysis study using qualitative thematic synthesis.A local higher education institution that conducted pre-registration nursing programs.A total of 189 undergraduate nursing students that were never attained any clinical placement prior to the parent study.Focus group interviews were conducted to collect data that were then transcribed and analyzed through the qualitative thematic synthesis approach to develop themes.Results:Three themes were emerged from the participants’simulation experiences in terms of peoples(the observers vs the observed),actions(the prepared vs the unprepared),and settings(the realism vs the simulation).Conclusions:By considering and reviewing the current design and development of the simulation practice,the findings of this study contribute to the body of knowledge with valuable insights on stress and anxiety that may affect students’learning in simulation.
基金supported by the China Scholarship Council(CSC,Grant No.202108050072)JSPS KAKENHI(Grant No.JP19KK0121)。
文摘Grouting has been the most effective approach to mitigate water inrush disasters in underground engineering due to its ability to plug groundwater and enhance rock strength.Nevertheless,there is a lack of potent numerical tools for assessing the grouting effectiveness in water-rich fractured strata.In this study,the hydro-mechanical coupled discontinuous deformation analysis(HM-DDA)is inaugurally extended to simulate the grouting process in a water-rich discrete fracture network(DFN),including the slurry migration,fracture dilation,water plugging in a seepage field,and joint reinforcement after coagulation.To validate the capabilities of the developed method,several numerical examples are conducted incorporating the Newtonian fluid and Bingham slurry.The simulation results closely align with the analytical solutions.Additionally,a set of compression tests is conducted on the fresh and grouted rock specimens to verify the reinforcement method and calibrate the rational properties of reinforced joints.An engineering-scale model based on a real water inrush case of the Yonglian tunnel in a water-rich fractured zone has been established.The model demonstrates the effectiveness of grouting reinforcement in mitigating water inrush disaster.The results indicate that increased grouting pressure greatly affects the regulation of water outflow from the tunnel face and the prevention of rock detachment face after excavation.
文摘Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing a greater role in the performance of components. This paper investigates the effect of heat treatment on residual stresses induced in AISI 1025, manufactured using LENS. Finite element model was developed and simulated to analyze residual stress development. AISI 1025 samples suitable for tool and die applications in Fused Deposition Modelling (FDM) filament production, were fabricated using Laser Engineered Net Shaping (LENS) process, followed by heat treatment where annealing and quenching processes were done. The material’s microstructure, residual stress and hardness of heat-treated samples under investigation, were compared against the as-built samples. The results indicated that after annealing, tensile residual stresses were reduced by 93%, resulting in a reduced crack growth rate, compared to the as-built sample, although the hardness was reduced significantly by 25%. On the other hand, high tensile residual stresses of 425 ± 14 MPa were recorded after quenching process with an improvement of hardness by 21%.
文摘Highly energy-efficient buildings have generated remarkable interest over the last few years.There is a need for simulation based effective control systems for efficient usage of electrical and fossil fuel driven devices,as they contribute to energy-efficient buildings and assist in gaining flexibility for the human occupancy-based energy loads.In this context,the integrated energy profile of a building can be ascertained by effective research approaches,as this knowledge would be beneficial to understand the demographics with respect to human occupancy and activities,as well as estimate varying energy consumption over time.Utility data from Smart Meter(SM)readings can reveal detailed information that could be mapped to predict resident occupancy and the usage patterns of specific types of appliances over desired time intervals.This research develops a user-driven simulation tool with realistic data acquisition options and assumptions of potential human behavior to determine energy usage patterns over time without the utility billing information.In this work,factors such as level of human occupancy,the possibility of space being occupied,thermostat settings,building envelope infrastructural aspects,types of appliances used in households,appliance energy related capacities,and the probability of using each appliance is considered,along with variance in weather,and heating-cooling systems specifications.For five specific benchmarked scenarios,the range of the random numbers is specified based on assumed potential human behavior for occupancy and energy-consuming appliances usage probabilities,with respect to the time of the day,weekday,and weekends.The simulation is developed using the Visual Basic Application(VBA)^(R)in Microsoft Excel^(R),based on the discrete-event Monte Carlo Simulation(MCS).The simulated energy usage and the cost are reflected in the sensitivity analysis by comparing factors such as the level of human occupancy,appliance type,and time intervals.
文摘The aim of this study is to address the issues associated with traditional magnetorheological fluid(MRF)dampers,such as insufficient damping force after power failure and susceptibility to settlement.In order to achieve this,a bidirectional adjustable MRF damper was designed and developed.Magnetic field simulation analysis was conducted on the damper,along with simulation analysis on its dynamic characteristics.The dynamic characteristics were ultimately validated through experimental testing on the material testing machine,thereby corroborating the theoretical simulation results.Concurrently,this process generated valuable test data for subsequent implementation of the semi-active vibration control system.The simulation and test results demonstrate that the integrated permanent magnet effectively accomplishes bidirectional regulation.The magnetic induction intensity of the damping channel is 0.2 T in the absence of current,increases to 0.5 T when a maximum forward current of 4 A is applied,and becomes 0 T when a maximum reverse current of 3.8 A is applied.When the excitation amplitude is 8 mm and the frequency is 2 Hz,with the applied currents varying,the maximum damping force reaches 8 kN,while the minimum damping force measures at 511 N.Additionally,at zero current,the damping force stands at 2 kN,which aligns closely with simulation results.The present paper can serve as a valuable reference for the design and research of semi-active MRF dampers.
基金supported by the National Natural Science Foundation of China(Grant Nos.42477185,41602308)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY20E080005)the Postgraduate Course Construction Project of Zhejiang University of Science and Technology(Grant No.2021yjskj05).
文摘The utilization of multi-field coupling simulation methods has become a pivotal approach for the investigation of intricate fracture behavior and interaction mechanisms of rock masses in deep strata.The high temperatures,pressures and complex geological environments of deep strata frequently result in the coupling of multiple physical fields,including mechanical,thermal and hydraulic fields,during the fracturing of rocks.This review initially presents an overview of the coupling mechanisms of these physical fields,thereby elucidating the interaction processes ofmechanical,thermal,and hydraulic fields within rockmasses.Secondly,an in-depth analysis ofmulti-field coupling is conducted from both spatial and temporal perspectives,with the introduction of simulation methods for a range of scales.It emphasizes cross-scale coupling methodologies for the transfer of rock properties and physical field data,including homogenization techniques,nested coupling strategies and data-driven approaches.To address the discontinuous characteristics of the rock fracture process,the review provides a detailed explanation of continuousdiscontinuous couplingmethods,to elucidate the evolution of rock fracturing and deformationmore comprehensively.In conclusion,the review presents a summary of the principal points,challenges and future directions of multi-field coupling simulation research.It also puts forward the potential of integrating intelligent algorithms with multi-scale simulation techniques to enhance the accuracy and efficiency of multi-field coupling simulations.This offers novel insights into multi-field coupling simulation analysis in deep rock masses.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3404904)。
文摘The coupling between heat and pressure is the kernel of inertia friction welding(IFW)and is still not fully understood.A novel 3D fully coupled finite element model based on a plastic friction pair was developed to simulate the IFW process of a Ni-based superalloy and reveal the omnidirectional thermo-mechanical coupling mechanism of the friction interface.The numerical model successfully simulated the deceleration,deformation processes,and peak torsional moments in IFW and captured the evolution of temperature,contact pressure,and stress.The simulated results were validated through measured thermal history,optical macrography,and axial shortening.The results indicated that interfacial friction heat was the primary heat source,and plastic deformation energy only accounted for 4%of the total.The increase in initial rotational speed and friction pressure elevated the peak temperature,reaching a maximum of 1525.5K at an initial rotational speed of 2000 r/min and friction pressure of 400 MPa.The interface heat generation could form an axial temperature gradient exceeding 320K/mm.The radial inhomogeneities of heat generation and temperature were manifested in a concentric ring distribution with maximum heat flux and temperature ranging from 2/5 to 2/3 radius.The radial inhomogeneities were caused by increasing linear velocity along the radius and an opposite distribution of contact pressure,which could reach 1.7 times the set pressure at the center.The circumferential inhomogeneity of thermomechanical distribution during rotary friction welding was revealed for the first time,benefiting from the 3D model.The deflection and transformation of distribution in contact pressure and Mises stress were indicators of plastic deformation and transition of quasi-steady state welding.The critical Mises stress was 0.5 times the friction pressure in this study.The presented modeling provides a reliable insight into the thermo-mechanical coupling mechanism of IFW and lays a solid foundation for predicting the microstructures and mechanical properties of inertia friction welded joints.
基金supported by the Chongqing Natural Science Foundation of Chongqing,China(No.CSTB2022NSCQ-MSX0333)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202401205)+1 种基金Chongqing Three Gorges University Graduate Research and Innovation Project Funding(No.YJSKY24045)Chongqing Engineering Research Center of Disaster Prevention&Control for Banks and Structures in Three Gorges Reservoir Area(No.SXAPGC24YB14,No.SXAPGC24YB03,No.SXAPGC24YB12)。
文摘Oil shale is characterized by a dense structure,low proportion of pores and fissures,and low permeability.Pore-fracture systems serve as crucial channels for shale oil migration,directly influencing the production efficiency of shale oil resources.Effectively stimulating oil shale reservoirs remains a challenging and active research topic.This investigation employed shale specimens obtained from the Longmaxi Formation.Scanning electron microscopy,fluid injection experiments,and fluid-structure interaction simulations were used to comprehensively analyze structural changes and fluid flow behavior under high temperatures from microscopic to macroscopic scales.Experimental results indicate that the temperature has little effect on the structure and permeability of shale before 300℃.However,there are two threshold temperatures within the range of 300 to 600℃that have significant effects on the structure and permeability of oil shale.The first threshold temperature is between 300 and 400℃,which causes the oil shale porosity,pore-fracture ratio,and permeability begin to increase.This is manifested by the decrease in micropores and mesopores,the increase in macropores,and the formation of a large number of isolated pores and fissures within the shale.The permeability increases but not significantly.The second threshold temperature is between 500 and 600℃,which increases the permeability of oil shale significantly.During this stage,micropores and mesopores are further reduced,and macropores are significantly enlarged.A large number of connected and penetrated pores and fissures are formed.More numerous and thicker streamlines appear inside the oil shale.The experimental results demonstrate that high temperatures significantly alter the microstructure and permeability of oil shale.At the same time,the experimental results can provide a reference for the research of in-situ heating techniques in oil shale reservoir transformation.
基金supported by the National Natural Science Foundation of China(No.52272428)。
文摘The electro⁃thermal anti/de-icing systems have high heating efficiency and relatively simple structures,marking them as a key development direction for future icing protection.Existing simulation algorithms for electrothermal de-icing seldom delve into comprehensive ice accretion-melting-deicing models that account for ice shedding.Therefore,the detachment behavior of ice layers during the heating process requires in-depth research and discussion.This paper physically models the phenomenon of ice shedding,incorporates the detachment behavior of ice layers during heating,improves the existing mathematical model for electro-thermal de-icing calculations,establishes an ice accretion-melting-deicing model for electro-thermal de-icing systems,and conducts numerical simulation,verification and optimization analysis of electro-thermal de-icing considering ice shedding.Through multi-condition de-icing numerical simulations of a specific wing model,it is found that ambient temperature can serve as a factor for adapting the electro heating anti/de-icing strategy to the environment.An optimization of heating heat flux density and heating/cooling time is conducted for the wing de-icing control law under the calculated conditions.The improved electrothermal de-icing model and algorithm developed in this paper provide solid technical support for the design of electrothermal de-icing systems.
基金supported by the National Natural Science Foundation of China(Grant Numbers 42374195 and 42188101)the fellowship of China National Postdoctoral Program for Innovative Talents(Grant Number BX20230273)+1 种基金the Hubei Provincial Natural Science Foundation of China(Grant Number 2024AFB-097)the Postdoctor Project of Hubei Province(Grant Number 2024HBBHCXA054).
文摘This study employs Principal Component Analysis(PCA)and 13 years of SD-WACCM-X model data(2007-2019)to investigate the characteristics and mechanisms of Inter-hemispheric Coupling(IHC)triggered by sudden stratospheric warming(SSW)events.IHC in both hemispheres leads to a cold anomaly in the equatorial stratosphere,a warm anomaly in the equatorial mesosphere,and increased temperatures in the mesosphere and lower thermosphere(MLT)region of the summer hemisphere.However,the IHC features during boreal winter period are significantly weaker than during the austral winter period,primarily due to weaker stationary planetary wave activity in the Southern Hemisphere(SH).During the austral winter period,IHC results in a warm anomaly in the polar mesosphere of the SH,which does not occur in the NH during boreal winter period.This study also examines the possible influence of quasi-two-day waves(QTDWs)on IHC.We found that the largest temperature anomaly in the summer polar MLT region is associated with a large wind instability area,and a well-developed critical layer structure of QTDW in January.In contrast,during July,despite favorable conditions for QTDW propagation in the Northern Hemisphere,weaker IHC response is observed,suggesting that IHC features and the relationship with QTDWs during July would be more complex than during January.
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 National Natural Science Foundation of China(Nos.52364044 and 52204364)Central Guidance on Local Science and Technology Development Fund Projects of Inner Mongolia Autonomous Region(No.2022ZY0090)Basic Scientific Research Business Expenses of Colleges and Universities in Inner Mongolia Autonomous Region(Nos.2023QNJS011 and 0406082226).
文摘The micro-area characterization experiments like scanning Kelvin probe force microscope(SKPFM)and Kernel average misorientation have the defects of complex sample preparation and occasional errors in test results,which makes it impossible to accurately and quickly analyze the pitting behavior induced by inclusions in some cases,prompting attempts to turn to simulation calculation research.The method of calculating band structure and work function can be used to replace current-sensing atomic force microscopy and SKPFM to detect the potential and conductivity of the sample.The band structure results show that Al_(2)O_(3) inclusion is an insulator and non-conductive,and it will not form galvanic corrosion with the matrix.Al_(2)O_(3) inclusion does not dissolve because its work function is higher than that of the matrix.Moreover,the stress concentration of the matrix around the inclusion can be characterized by first-principles calculation coupled with finite element simulation.The results show that the stress concentration degree of the matrix around Al_(2)O_(3) inclusion is serious,and the galvanic corrosion is formed between the high and the low stress concentration areas,which can be used to explain the reason of the pitting induced by Al_(2)O_(3) inclusions.
基金supported by the National Key Research and Development Program of China(Nos.2022YFA1204203 and 2022YFA1204201)Opening Fund of the State Key Laboratory of Optoelectronic Materials and Technologies at Sun Yat-sen University(No.OEMT-2023-KF-01)+1 种基金National Natural Science Foundation of China(Nos.61971463,82272131,and 82202960)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010537).
文摘Flat-panel X-ray sources(FPXSs)have many advantages in terms of compactness and low-dose imaging,enhancing their capability for novel X-ray applications.Experimental analysis of the X-ray characteristics and optimizing the anode panel of an FPXS are time-consuming,expensive,and sometimes impractical.In this study,a FPXS was prepared using a ZnO nanowire cold cathode and a molybdenum film anode target.Monte Carlo(MC)simulations were utilized to optimize the anode panel and obtain the average fluence,average energy,and spatial distribution of the X-rays for the ZnO nanowire FPXS.The accuracy of the MC simulations was verified by comparing the measured and simulated energy spectra.Optimization of the anode target considers the material,thickness,and morphology,whereas optimization of the substrate focuses on the material and thickness.The results show that the difference between the positions of the K-shell peaks in the measured and simulated energy spectra is within 0.26 keV.At the acceleration voltages of 30 kV,60 kV,and 90 kV,the optimal thicknesses of the tungsten array anode were 0.65μm,2.45μm,and 5μm,respectively,while the molybdenum array anode has the optimal thicknesses of 1.45μm,5.25μm,and 24μm,respectively.The microsemi-ellipsoidal anode with a recessed design showed a 5%increase in the transmitted X-ray fluence compared with the film target.The sapphire substrate with a thickness of 0.78 mm exhibits a mechanical strength comparable to that of a glass substrate with a thickness of 3 mm,implying that the former can increase the average X-ray fluence by reducing the filtration of X-rays.The findings of this study provide valuable guidance for the fabrication and optimization of the ZnO nanowire FPXS.
基金Ministry of Science and Technology of China under Grant No.2023YFC3804300National Science Foundation of China under Grant No.52178114。
文摘Actuator dynamics introduce a synchronization disparity between commanded displacements transmitted to the actuator and the actual displacements generated by the actuator,thereby affecting its precision and potentially leading to instability in real-time hybrid simulation(RTHS).This study aims to elucidate the relationship between calculated and measured displacements by analyzing their magnitude and phase in the frequency domain via transformations.The physical implications of these relationships are explored in the context of frequency domain evaluation indices(FEI),the transfer function of actuator dynamics,and delay compensation.Formulations for achieving perfect compensation of actuator dynamics are developed,and an enhanced compensation approach,termed improved windowed frequency domain evaluation index-based compensation(IWFEI),is introduced.The efficacy of IWFEI is assessed using a RTHS benchmark model,with perturbed simulations conducted to validate its robustness.Uncertainties inherent in actuator dynamics are represented as random variables in these simulations.Comparative analysis of the mean values and variances of evaluation criteria demonstrates that IWFEI enables more accurate and robust compensation.Furthermore,strong correlations observed among criteria in the time and frequency domains underscore the effectiveness of the proposed frequency domain-based compensation method in mitigating amplitude errors and phase delays in RTHS.
基金Under the auspices of Zhejiang Provincial Natural Science Foundation of China(No.LY19C160007)。
文摘In recent years,rapid urbanization has had a profound impact on landscape stability.As a typical example of China's rapid urbanization,Hangzhou has also experienced significant landscape changes,which have profoundly affected its ecological stability.Taking Hangzhou as an example,this study integrates land use change data from 1980 to 2020,combines dynamic simulation and ecological modeling techniques,and carries out a comprehensive analysis of historical trends and future predictions,to provide valuable insights into the complex interactions between urban expansion and landscape stability.The results indicate that:1)between 1980 and2020,Hangzhou experienced a significant increase in construction land at the expense of arable land,leading to a gradual decline in landscape stability,though the downward trend has slowed in recent years.2)The spatial distribution of landscape stability shows clear aggregation patterns,with lower stability concentrated in economically active flatlands and higher stability in the mountainous western regions.3)By 2040,further urban expansion is predicted to occur alongside increased landscape integration,reflecting the positive effects of ecological protection strategies.This study highlights the universal challenges of balancing economic growth with ecological stability in rapidly urbanizing regions.The combination of advanced simulation models and spatiotemporal analysis demonstrates a replicable framework for assessing urban expansion's ecological impacts.These findings underscore the importance of tailoring urban planning and ecological policies to address regional disparities,providing valuable insights for sustainable urban development and landscape management globally.
基金National Key R&D Program of China under Grant No.2022YFC3003600National Natural Science Foundation of China(NSFC)under Grant No.51978023。
文摘Due to uncertainties in seismic pipeline damage and post-earthquake recovery processes,probabilistic characteristics such as mean value,standard deviation,probability density function,and cumulative distribution function provide valuable information.In this study,a simulation-based framework to evaluate these probabilistic characteristics in water distribution systems(WDSs)during post-earthquake recovery is developed.The framework first calculates pipeline failure probabilities using seismic fragility models and then generates damage samples through quasi-Monte Carlo simulations with Sobol’s sequence for faster convergence.System performance is assessed using a hydraulic model,and recovery simulations produce time-varying performance curves,where the dynamic importance of unrepaired damage determines repair sequences.Finally,the probabilistic characteristics of seismic performance indicators,resilience index,resilience loss,and recovery time are evaluated.The framework is applied in two benchmark WDSs with different layouts to investigate the probabilistic characteristics of their seismic performance and resilience.Application results show that the cumulative distribution function reveals the variations in resilience indicators for different exceedance probabilities,and there are dramatic differences among the recovery times corresponding to the system performance recovery targets of 80%,90%,and 100%.
基金supported by the National Natural Science Foundation of China(No.22074058,S.Li).
文摘Algal copper uptake(i.e.,Cu bioavailability)in the euphotic zone plays a vital role in algal photosynthesis and respiration,affecting the primary productivity and the source and sink of atmospheric carbon.Algal Cu uptake is controlled by natural dissolved organic Cu(DOCu)speciation(i.e.,complexed with the dissolved organic matter)that conventionally could be tested by model prediction or molecular-level characterizations in the lab,while DOCu uptake are hardly directly assessed.Thus,the new chemistrybiology insight into the mechanisms of the Cu uptake process in algae is urgent.The DOCu speciation transformation(organic DOCu to free Cu(II)ions),enzymatic reduction-induced valence change(reduction of free Cu(II)to Cu(I)ions),and algal Cu uptake at the algae-water interface are imitated.Herein,an intelligent system with DOCu colorimetric sensor is developed for real-time monitoring of newly generated Cu(I)ions.Deep learning with whole sample image-based characterization and powerful feature extraction capabilities facilitates colorimetric measurement.In this context,the Cu bioavailability with 7 kinds of organic ligands(e.g.,amino acids,organic acids,carbohydrates)can be predicted by the mimetic intelligent biosensor within 15.0min,i.e.,the DOCu uptake and speciation is successfully predicted and streamlined by the biomimetic approach.
