The aim of the study is to simulate actual operation of an elevator. First, it designed elevator scheduling algorithm for control ing operation of the elevator;second, it simulated elevator operation by the use of obj...The aim of the study is to simulate actual operation of an elevator. First, it designed elevator scheduling algorithm for control ing operation of the elevator;second, it simulated elevator operation by the use of object-oriented programming language, in which double buffering technology was used to solve the problem of elevator pictures flicker at refreshing; final y, test correctness and rationality of the system.展开更多
Evaluating Unmanned Aerial Vehicle(UAV)systems within a System-of-Systems(SoS)environment helps clarify their contribution to the overall combat capability and supports effectiveness-oriented system optimization.When ...Evaluating Unmanned Aerial Vehicle(UAV)systems within a System-of-Systems(SoS)environment helps clarify their contribution to the overall combat capability and supports effectiveness-oriented system optimization.When assessing decision systems in such an environment,cross-level modeling and simulation are required,which often face a trade-off between low modeling cost and high simulation accuracy,while the credibility of results remains challenging to ensure.To address these issues,this study proposes a hybrid-granularity Hardware-In-the-Loop(HIL)SoS environment construction method based on Graphical Evaluation and Review Technique(GERT).The method employs GERT to analyze the relationships between simulation systems,the System Under Test(SUT),and mission outcomes,thereby determining the required model precision for different systems.A dynamic resource allocation algorithm is applied to adjust model granularity on demand,ensuring high-fidelity simulation under constrained total cost.Additionally,GERT estimates the computational frequency and communication bandwidth requirements of the SUT,guiding hardware selection to enhance simulation credibility.A UAV maritime combat case study was conducted for validation.The results demonstrate that,compared to the flat modeling approach,the hybrid-granularity scenario based on GERT analysis achieves higher simulation accuracy with lower overall model complexity.The coefficient of variation in evaluation results significantly decreases in HIL simulations compared to virtual simulations,confirming improved credibility.Under the hybrid-granularity HIL scenario,the decision system was evaluated from an effectiveness perspective,identifying the most sensitive performance parameter.Subsequent targeted optimization led to an 11.90%improvement in effectiveness,validating the method's practical utility.展开更多
A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow.Key parameters were extracted,and Spearman correlation analysis was used to quantify the...A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow.Key parameters were extracted,and Spearman correlation analysis was used to quantify the relationships among bubble behavior,circulating flow,and liquid oscillations.The results show that periodic bubble behavior under steady injection drives the circulating flow of the liquid on both sides.The asynchronism of bubble behavior on both sides results in the alternation of circulating intensity,which significantly enhances gas−liquid mixing efficiency at certain liquid levels of 200 and 220 mm.Flow patterns of the double-side-blown process are classified into weak circulation,strong−weak alternating circulation,and strong circulation modes based on the influence of circulating flows on the penetration depth.The penetration depth in the strong−weak alternating circulation mode is generally greater than that in the single-side-blown process.The imbalance of circulating intensities on both sides primarily leads to the stable fluctuation in the injecting direction,which reveals the appearance of periodic oscillations in the molten bath.The effect of control parameters such as liquid level and gas flow rate on the liquid oscillations were discussed.展开更多
Roof pre-fracture poses a considerable risk during the re-mining of residual coal above abandoned roadways,threatening the safety of the mining faces.This study employs a Winkler foundation beam model for mechanical a...Roof pre-fracture poses a considerable risk during the re-mining of residual coal above abandoned roadways,threatening the safety of the mining faces.This study employs a Winkler foundation beam model for mechanical analysis of roof structures and adopts a multivariate nonlinear analysis approach to explore the synergistic load-bearing effects within the'coal pillar-support-backfill body'system during the fill and re-mining processes above these roadways.The findings demonstrate that backfill mining significantly reduces stress concentrations in coal pillars and reduces excessive bending moments in roofs near abandoned roadways.The roof deflection equation incorporates three critical factors affecting stability during backfill mining:the width of the coal pillar(L_(3)),the working resistance of the support(q_(z)),and the elastic foundation coefficient of the backfill material(kcÞ.Under single-factor conditions,the impact sequence on roof stability in the coal pillar zone is·k_(c)>L_(3)>q_(z).Further,multivariate nonlinear analysis reveals the interactions within the'coal-support-backfill'structure,indicating that in terms of roof control,the interaction terms are ordered as L_(3)·k_(c)>q_(z)·k_(c)>L_(3)q_(z).Therefore,priority should be given to adjusting the coal pillar width and backfill strength,followed by modifications to the support resistance and backfill strength during the recovery of abandoned roadways.An improved understanding of these interactions will help optimize strategies for the recovery of residual coal through abandoned roadways,thereby enhancing the stability and safety of mining operations under complex geological conditions.展开更多
This study investigates in-station pressure drop mechanisms in a shale gas gathering system,providing a quantitative basis for flow system optimization.Computational fluid dynamics(CFD)simulations,based on field-measu...This study investigates in-station pressure drop mechanisms in a shale gas gathering system,providing a quantitative basis for flow system optimization.Computational fluid dynamics(CFD)simulations,based on field-measured parameters related to a representative case(a shale gas platform located in Sichuan,China)are conducted to analyze the flow characteristics of specific fittings and manifolds,and to quantify fitting resistance coefficients and manifold inlet interference.The resulting coefficients are integrated into a full-station gathering network model in PipeSim,which,combined with production data,enables evaluation of pressure losses and identification of equivalent pipeline blockages.The results indicate that the resistance coefficients,valid only for fittings under the studied field-specific geometries,are 0.21 for 90◦elbows in the fully open position,0.16 for gate valve passages in the fully open position,and 2.3 for globe valve passages.Manifold interference decreases with lower high-pressure inlet values,whereas inlets farther from the high-pressure side experience stronger disturbances.Interestingly,significant discrepancies between simulated and measured pressure drops reveal partial blockages,corresponding to effective diameter reductions of 65 mm,38 mm,44 mm,38 mm,and 28 mm for Wells 1#,3#,5#,and 6#,respectively.展开更多
Automation and intelligence have become the primary trends in the design of investment casting processes.However,the design of gating and riser systems still lacks precise quantitative evaluation criteria.Numerical si...Automation and intelligence have become the primary trends in the design of investment casting processes.However,the design of gating and riser systems still lacks precise quantitative evaluation criteria.Numerical simulation plays a significant role in quantitatively evaluating current processes and making targeted improvements,but its limitations lie in the inability to dynamically reflect the formation outcomes of castings under varying process conditions,making real-time adjustments to gating and riser designs challenging.In this study,an automated design model for gating and riser systems based on integrated parametric 3D modeling-simulation framework is proposed,which enhances the flexibility and usability of evaluating the casting process by simulation.Firstly,geometric feature extraction technology is employed to obtain the geometric information of the target casting.Based on this information,an automated design framework for gating and riser systems is established,incorporating multiple structural parameters for real-time process control.Subsequently,the simulation results for various structural parameters are analyzed,and the influence of these parameters on casting formation is thoroughly investigated.Finally,the optimal design scheme is generated and validated through experimental verification.Simulation analysis and experimental results show that using a larger gate neck(24 mm in side length) and external risers promotes a more uniform temperature distribution and a more stable flow state,effectively eliminating shrinkage cavities and enhancing process yield by 15%.展开更多
Objective:A computer-based STS(simulative training system) in providing pre-hospital trauma care at a disaster site was applied to teaching nursing students in the Second Military Medical University,China.This article...Objective:A computer-based STS(simulative training system) in providing pre-hospital trauma care at a disaster site was applied to teaching nursing students in the Second Military Medical University,China.This article reports on the teaching effectiveness of this system.Methods:Among 92 participants,46 were in the study group and 46 were in the 'control' group. Each student completed a multiple-choice quiz after completing 18 hours(six three-hour sessions) of the study module,and a score was recorded.The simulative training module was completed only by the study group;the 'control' group was assigned in-class discussions for the same amount of time covering the same content as the study group.The final course scores,which included both comprehensive and group task-based tests were compared between these two groups.The study used a descriptive and comparative approach for quantitative data analysis.Tests of independency between the multiple choice scores and the simulation scores were also performed.Finally,anonymous surveys were conducted.Results:The study group performed better than the 'control' group with a significantly higher average score for the group scenario task-based test score,and consequently the study group's final course score was significantly higher than the 'control' group.As per chi-square tests,no significant associations were found between the multiple choice scores and the simulated training scores.The final surveys showed students overwhelmingly agreed that STS training improved their knowledge and skills,their ability to recognize a potential critical event, and their initial response for trauma care at pre-hospital settings.The survey responses of the study group were noteworthy as they indicated that students recognized the importance of simulative training,appreciated the realism of the simulation,and were able to fight/adjust to the stressful feelings in order to focus on the task.Conclusion:Computer-based STS may be an effective teaching model to help students improve their capability in providing pre-hospital trauma care,and in their effectiveness in disaster response.展开更多
Computer simulation was used for hydraulic lifting systems. Based on theoryof multiphase flows and their applications on the lifting systems, mathematical models for pumplifting and air lifting were built and simulati...Computer simulation was used for hydraulic lifting systems. Based on theoryof multiphase flows and their applications on the lifting systems, mathematical models for pumplifting and air lifting were built and simulative analysis programs for them were developedrespectively. Corresponding lifting behaviors and system parameters were analyzed and optimum matchof the parameters for future pilot mining tests and commercial mining production was predicted.展开更多
The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model.To address the limitations of traditional methods in obtaining high-quality se...The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model.To address the limitations of traditional methods in obtaining high-quality sediment,a novel sampling system with 6000 m operational capability and three-month endurance was developed.It is equipped with three sediment samplers,a set of formaldehyde preservation solution injection devices.The system is controlled by a low-power,timing-triggered controllers.To investigate low-disturbance rheological mechanisms,gap controlled rheological tests were conducted to optimize the structural design of the sampling and sealing assembly.Stress-controlled shear rheological tests were employed to investigate the mechanisms governing yield stress in sediments under varying temperature conditions and boundary roughness.Additionally,the coupled Eulerian-Lagrangian(CEL)method and sediment rheological constitutive models were employed to simulate tube-soil interaction dynamics and sediment disturbance.The radial heterogeneity of sediment disturbance and friction variation of the sampling tube were revealed.The tube was completely“plugged”at a penetration depth of 261 mm,providing critical data support to the penetration depth parameters.The deep-sea pressure test and South China Sea field trials demonstrated the system’s capability to collect and preserve quantitative time-series sediment samples with high fidelity.展开更多
Two-photon fluorescence microscopy,based on the principles of two-photon excited fluorescence and second harmonic generation,enables real-time non-invasive in vivo imaging of skin and cells,providing a means to assess...Two-photon fluorescence microscopy,based on the principles of two-photon excited fluorescence and second harmonic generation,enables real-time non-invasive in vivo imaging of skin and cells,providing a means to assess human health status.In this paper,a miniaturized two-photon imaging system is designed and fabricated to withstand extreme vibration and shock environments.The mechanical stability of the optical and structural components of the miniaturized probe is evaluated under random vibration and shock vibration tests using finite element simulation methods and ray tracing techniques.During the environmental testing,the maximum stress on the probe is 11.5 MPa,which is well below the threshold for structural failure.The largest structural displacement occurs at the collimator,where random vibrations produce an offset of 10.9μm.This offset is analyzed by using geometric optics and point spread functions.Under the maximum collimator offset,the theoretical resolution,as calculated by the point spread function,shifted from 463.28 nm to 463.48 nm.Additionally,a lateral offset of 127 nm is observed at the center position,which does not significantly impact the imaging performance.Finally,environmental and imaging performance tests are conducted.The system’s measured resolution after the environmental tests is 530 nm,consistent with its resolution prior to testing.Imaging tests are also performed on the skin’s stratum corneum,granular layer,spinous layer,and basal cell layer,revealing clear cellular structural information.These results confirm the device’s potential for applications in extreme shock and vibration environments.展开更多
Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based ...Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based on the system dynamics methodology.The introduction of Wolbachia-carrying mosquitoes aims to reduce dengue transmission by interfering with the reproductive capacity of mosquitoes,thus limiting the spread of the virus.Objective:the objective of this study is to analyze how this intervention affects not only the incidence of dengue but also the health care system,evaluating changes in the demand for medical services and the costs associated with treatment in health care institutions.Specifically,it looks at the cost per visit to an Epidemiologist,a Family Doctor,diagnostic tests,and hospitalization.Methods:the study uses simulation scenarios to model the potential impact of the Wolbachia-based intervention in reducing dengue cases and its associated health and economic burden.The scenarios also assess the optimization of resources and improvements in the health system’s response to epidemic outbreaks.The simulation model utilizes real data from the Americas region to enhance the accuracy and relevance of the results.Conclusion:The results the potential of the release of Wolbachia-carrying mosquitoes to significantly mitigate the health and economic burden of dengue,with a maximum saving of 60.15%in the best simulation scenario.The approach not only highlights scientific innovation but also demonstrates its potential influence on public policy design.The findings support the implementation of sustainable strategies to maximize the benefits of this intervention and ensure its effective integration into public health programs,contributing to better long-term dengue management.展开更多
Heating,Ventilation,andAir Conditioning(HVAC)systems are critical formaintaining thermal comfort in office environments which also crucial for occupant well-being and productivity.This study investigates the impact of...Heating,Ventilation,andAir Conditioning(HVAC)systems are critical formaintaining thermal comfort in office environments which also crucial for occupant well-being and productivity.This study investigates the impact of integrating ceiling fans with higher air conditioning setpoints on thermal comfort and energy efficiency in office environments.Field measurements and questionnaire surveys were conducted to evaluate thermal comfort and energysaving potential under varying conditions.Results show that increasing the AC setpoint from 25○C to 27○C,combined with ceiling fan operation,reduced power consumption by 10%,achieving significant energy savings.Survey data confirmed that 85%of participants reported consistent thermal sensations across all conditions,with ceiling fans effectively compensating for higher setpoints through enhanced air circulation.CFDsimulations revealed that mediumspeed ceiling fan operation produced the most uniformairflowdistribution,with an average air velocity of 0.45 m/s,and minimized temperature variations,ensuring balanced thermal conditions.Temperature analysis showed a reduction in hotspots and cold zones,maintaining an average temperature deviation of less than±0.5○C.Predicted Mean Vote(PMV)evaluations at a 27○C setpoint indicated improved thermal comfort,with average PMV values around−0.3,corresponding to a“neutral”thermal sensation.These findings demonstrate the effectiveness of integrating ceiling fans with HVAC systems in achieving energy efficiency and occupant comfort,offering a sustainable approach to reducing AC energy consumption in office environments.展开更多
This study addresses the limitations of traditional disaster medicine course assessments,including single evaluation formats,delayed feedback mechanisms,and gaps in competency mapping,by developing a diversified asses...This study addresses the limitations of traditional disaster medicine course assessments,including single evaluation formats,delayed feedback mechanisms,and gaps in competency mapping,by developing a diversified assessment system leveraging the Rain Classroom platform.The system incorporates six interconnected evaluation components across the learning cycle:pre-class preparation,pre-class tests,case discussions,skills assessment,post-class tests,and post-class feedback,collectively forming a three-dimensional“cognitive-skill-attitude”assessment framework.In the assessment design,the weighting of practical skill evaluation is elevated to 40%to prioritize the development of students’disaster response competencies.Additionally,an innovative multi-subject evaluation model(“self-peer-teacher”)is implemented within disaster scenario simulations,utilizing standardized scoring rubrics.This methodology not only enables comprehensive performance evaluation but also fosters critical teamwork and reflective practice.Implementation outcomes demonstrated that the system effectively evaluates learning progress through multi-modal assessments,enhances disaster rescue knowledge and skill proficiency,and successfully achieves predefined pedagogical objectives.展开更多
To explore atomic-level phenomena in the Cu-Ni-Sn alloy,a second nearest-neighbor modified embedded-atom method(2NN MEAM)potential has been developed for the Cu-Ni-Sn system,building upon the work of other researchers...To explore atomic-level phenomena in the Cu-Ni-Sn alloy,a second nearest-neighbor modified embedded-atom method(2NN MEAM)potential has been developed for the Cu-Ni-Sn system,building upon the work of other researchers.This potential demonstrates remarkable accuracy in predicting the lattice constant,with a relative error of less than 0.5%when compared to density functional theory(DFT)results,and it achieves a 10%relative error in the enthalpy of formation compared to experimental data,marking substantial advancements over prior models.The bulk modulus is predicted with a relative error of 8%compared to DFT.Notably,the potential effectively simulates the processes of melting and solidification of Cu-15Ni-8Sn,with a simulated melting point that closely aligns with the experimental value,within a 7.5%margin.This serves as a foundation for establishing a 2NN MEAM potential for a flawless Cu-Ni-Sn system and its microalloying systems.展开更多
Variable air volume systems are widely used in trains as they provide effective energy savings for air conditioning.However,the design phase is usually carried out at a certain fixed airflow,resulting in a difference ...Variable air volume systems are widely used in trains as they provide effective energy savings for air conditioning.However,the design phase is usually carried out at a certain fixed airflow,resulting in a difference between the expected and actual flow fields.In this study,we first analyzed the flow field characteristics at variable airflow rates under isothermal conditions,and subsequently established a correlation equation between the airflow and the flow field parameters.The results show that the airflow just entering the compartment conforms to the characteristics of an attached jet,and then,after converging in the middle,conforms to the characteristics of a free jet.The flow field characteristics are significantly correlated with the Reynolds number(Re)and are limited by the small space inside the vehicle.When Re≥2650,the axial velocities all conform to the classical u_(m)/u_(0)−(x/b)^(r) or u_(m)/u_(0)−(y/b)^(r) law,the sectional velocities conform to the exponential and Gaussian distributions,and the characteristic thicknesses of the jets conform to a linear distribution.Derivation shows that the entrainment suction flow rate is related mainly to the initial flow rate and the air opening width.The results of this study will inform the design of ventilation systems for high-speed trains.展开更多
This study employs the Smoothed Particle Hydrodynamics(SPH)method to develop a computational fluid dynamics(CFD)model for analyzing the interaction between rogue waves and mooring systems.Four floating body configurat...This study employs the Smoothed Particle Hydrodynamics(SPH)method to develop a computational fluid dynamics(CFD)model for analyzing the interaction between rogue waves and mooring systems.Four floating body configurations are investigated:(1)dual rectangular prisms,(2)rectangular prism–sphere composites,(3)sphere–rectangular prism composites,and(4)dual spheres.These configurations are systematically evaluated under varying mooring conditions to assess their hydrodynamic performance and wave attenuation capabilities.The model accurately captures the complex fluid–structure interaction dynamics between moored floating breakwaters and incident wave fields.Among the configurations,the dual rectangular prism system demonstrates superior performance in both wave dissipation and mooring force reduction.Under conditions involving dual wave makers,the influence of floating body shape and number on wave height is found to be minimal.However,dual-body arrangements consistently outperform single-body setups in terms of both energy dissipation and structural stability.From a cost-efficiency perspective,the configuration comprising two rectangular prisms connected via a single mooring system offers significant advantages in material usage and deployment feasibility.展开更多
A state-of-the-art review is presented of mathematical manoeuvring models for surface ships and parameter estimation methods that have been used to build mathematical manoeuvring models for surface ships. In the first...A state-of-the-art review is presented of mathematical manoeuvring models for surface ships and parameter estimation methods that have been used to build mathematical manoeuvring models for surface ships. In the first part, the classical manoeuvring models, such as the Abkowitz model, MMG, Nomoto and their revised versions, are revisited and the model structure with the hydrodynamic coefficients is also presented.Then, manoeuvring tests, including both the scaled model tests and sea trials, are introduced with the fact that the test data is critically important to obtain reliable results using parameter estimation methods. In the last part, selected papers published in journals and international conferences are reviewed and the statistical analysis of the manoeuvring models, test data, system identification methods and environmental disturbances used in the paper is presented.展开更多
In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion s...In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.展开更多
Traditionally,a continuous-wave(CW)signal is used to simulate RF circuits during the design procedure,while the fabricated circuits are measured by modulated signals in the test phase,because modulated signals are use...Traditionally,a continuous-wave(CW)signal is used to simulate RF circuits during the design procedure,while the fabricated circuits are measured by modulated signals in the test phase,because modulated signals are used in reality.It is almost impossible to use a CW signal to predict system performances,such as error vector magnitude(EVM),bit error rate(BER),etc.,of a transceiver front-end when dealing with complex modulated signals.This paper develops an integrated system evaluation engine(ISEE)to evaluate the system performances of a transceiver front-end or its sub-circuits.This crossdomain simulation platform is based on Matlab,advanced design system(ADS),and Cadence simulators to link the baseband signals and transceiver frond-end.An orthogonal frequency division multiplex(OFDM)modem is implemented in Matlab for evaluating the system performances.The modulated baseband signal from Matlab is dynamically fed into ADS,which includes transceiver front-end for co-simulation.The sub-block circuits of the transceiver front-end can be implemented using ADS and Cadence simulators.After system-level circuit simulation in ADS,the output signal is dynamically delivered to Matlab for demodulation.To simplify the use of the co-simulation platform,a graphical user interface(GUI)is constructed using Matlab.The parameters of the OFDM signals can be easily reconfigured on the GUI to simulate RF circuits with different modulation schemes.To demonstrate the effectiveness of the ISEE,a 3.5 GHz power amplifier is simulated and characterized using 20 MHz 16-and 64-QAM OFDM signals.展开更多
This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification metho...This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.展开更多
基金Supported by the Principal Fund Project of Tarim University(TDZKSSZD201207)~~
文摘The aim of the study is to simulate actual operation of an elevator. First, it designed elevator scheduling algorithm for control ing operation of the elevator;second, it simulated elevator operation by the use of object-oriented programming language, in which double buffering technology was used to solve the problem of elevator pictures flicker at refreshing; final y, test correctness and rationality of the system.
基金funded by Henan Key Laboratory of General Aviation Technology,grant number ZHKF-240202。
文摘Evaluating Unmanned Aerial Vehicle(UAV)systems within a System-of-Systems(SoS)environment helps clarify their contribution to the overall combat capability and supports effectiveness-oriented system optimization.When assessing decision systems in such an environment,cross-level modeling and simulation are required,which often face a trade-off between low modeling cost and high simulation accuracy,while the credibility of results remains challenging to ensure.To address these issues,this study proposes a hybrid-granularity Hardware-In-the-Loop(HIL)SoS environment construction method based on Graphical Evaluation and Review Technique(GERT).The method employs GERT to analyze the relationships between simulation systems,the System Under Test(SUT),and mission outcomes,thereby determining the required model precision for different systems.A dynamic resource allocation algorithm is applied to adjust model granularity on demand,ensuring high-fidelity simulation under constrained total cost.Additionally,GERT estimates the computational frequency and communication bandwidth requirements of the SUT,guiding hardware selection to enhance simulation credibility.A UAV maritime combat case study was conducted for validation.The results demonstrate that,compared to the flat modeling approach,the hybrid-granularity scenario based on GERT analysis achieves higher simulation accuracy with lower overall model complexity.The coefficient of variation in evaluation results significantly decreases in HIL simulations compared to virtual simulations,confirming improved credibility.Under the hybrid-granularity HIL scenario,the decision system was evaluated from an effectiveness perspective,identifying the most sensitive performance parameter.Subsequent targeted optimization led to an 11.90%improvement in effectiveness,validating the method's practical utility.
基金financial support for this research work from the National Key Research and Development Program of China(No.2022YFB3304901)。
文摘A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow.Key parameters were extracted,and Spearman correlation analysis was used to quantify the relationships among bubble behavior,circulating flow,and liquid oscillations.The results show that periodic bubble behavior under steady injection drives the circulating flow of the liquid on both sides.The asynchronism of bubble behavior on both sides results in the alternation of circulating intensity,which significantly enhances gas−liquid mixing efficiency at certain liquid levels of 200 and 220 mm.Flow patterns of the double-side-blown process are classified into weak circulation,strong−weak alternating circulation,and strong circulation modes based on the influence of circulating flows on the penetration depth.The penetration depth in the strong−weak alternating circulation mode is generally greater than that in the single-side-blown process.The imbalance of circulating intensities on both sides primarily leads to the stable fluctuation in the injecting direction,which reveals the appearance of periodic oscillations in the molten bath.The effect of control parameters such as liquid level and gas flow rate on the liquid oscillations were discussed.
基金support from National Natural Science Foundation of China(Grant No.52474142)The National Science Fund for Distinguished Young Scholars(No.51925402),Chinathe China Postdoctoral Science Foundation(Grant No.2021M702049).
文摘Roof pre-fracture poses a considerable risk during the re-mining of residual coal above abandoned roadways,threatening the safety of the mining faces.This study employs a Winkler foundation beam model for mechanical analysis of roof structures and adopts a multivariate nonlinear analysis approach to explore the synergistic load-bearing effects within the'coal pillar-support-backfill body'system during the fill and re-mining processes above these roadways.The findings demonstrate that backfill mining significantly reduces stress concentrations in coal pillars and reduces excessive bending moments in roofs near abandoned roadways.The roof deflection equation incorporates three critical factors affecting stability during backfill mining:the width of the coal pillar(L_(3)),the working resistance of the support(q_(z)),and the elastic foundation coefficient of the backfill material(kcÞ.Under single-factor conditions,the impact sequence on roof stability in the coal pillar zone is·k_(c)>L_(3)>q_(z).Further,multivariate nonlinear analysis reveals the interactions within the'coal-support-backfill'structure,indicating that in terms of roof control,the interaction terms are ordered as L_(3)·k_(c)>q_(z)·k_(c)>L_(3)q_(z).Therefore,priority should be given to adjusting the coal pillar width and backfill strength,followed by modifications to the support resistance and backfill strength during the recovery of abandoned roadways.An improved understanding of these interactions will help optimize strategies for the recovery of residual coal through abandoned roadways,thereby enhancing the stability and safety of mining operations under complex geological conditions.
基金the National Natural Science Foundation of China under Grant 52441411,52325402 and 52274057Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project under Grant 2024ZD1004302-04the National Key R&D Program of China under Grant 2023YFB4104200.
文摘This study investigates in-station pressure drop mechanisms in a shale gas gathering system,providing a quantitative basis for flow system optimization.Computational fluid dynamics(CFD)simulations,based on field-measured parameters related to a representative case(a shale gas platform located in Sichuan,China)are conducted to analyze the flow characteristics of specific fittings and manifolds,and to quantify fitting resistance coefficients and manifold inlet interference.The resulting coefficients are integrated into a full-station gathering network model in PipeSim,which,combined with production data,enables evaluation of pressure losses and identification of equivalent pipeline blockages.The results indicate that the resistance coefficients,valid only for fittings under the studied field-specific geometries,are 0.21 for 90◦elbows in the fully open position,0.16 for gate valve passages in the fully open position,and 2.3 for globe valve passages.Manifold interference decreases with lower high-pressure inlet values,whereas inlets farther from the high-pressure side experience stronger disturbances.Interestingly,significant discrepancies between simulated and measured pressure drops reveal partial blockages,corresponding to effective diameter reductions of 65 mm,38 mm,44 mm,38 mm,and 28 mm for Wells 1#,3#,5#,and 6#,respectively.
基金financially supported by the National Key Research and Development Program of China (2022YFB3706802)。
文摘Automation and intelligence have become the primary trends in the design of investment casting processes.However,the design of gating and riser systems still lacks precise quantitative evaluation criteria.Numerical simulation plays a significant role in quantitatively evaluating current processes and making targeted improvements,but its limitations lie in the inability to dynamically reflect the formation outcomes of castings under varying process conditions,making real-time adjustments to gating and riser designs challenging.In this study,an automated design model for gating and riser systems based on integrated parametric 3D modeling-simulation framework is proposed,which enhances the flexibility and usability of evaluating the casting process by simulation.Firstly,geometric feature extraction technology is employed to obtain the geometric information of the target casting.Based on this information,an automated design framework for gating and riser systems is established,incorporating multiple structural parameters for real-time process control.Subsequently,the simulation results for various structural parameters are analyzed,and the influence of these parameters on casting formation is thoroughly investigated.Finally,the optimal design scheme is generated and validated through experimental verification.Simulation analysis and experimental results show that using a larger gate neck(24 mm in side length) and external risers promotes a more uniform temperature distribution and a more stable flow state,effectively eliminating shrinkage cavities and enhancing process yield by 15%.
文摘Objective:A computer-based STS(simulative training system) in providing pre-hospital trauma care at a disaster site was applied to teaching nursing students in the Second Military Medical University,China.This article reports on the teaching effectiveness of this system.Methods:Among 92 participants,46 were in the study group and 46 were in the 'control' group. Each student completed a multiple-choice quiz after completing 18 hours(six three-hour sessions) of the study module,and a score was recorded.The simulative training module was completed only by the study group;the 'control' group was assigned in-class discussions for the same amount of time covering the same content as the study group.The final course scores,which included both comprehensive and group task-based tests were compared between these two groups.The study used a descriptive and comparative approach for quantitative data analysis.Tests of independency between the multiple choice scores and the simulation scores were also performed.Finally,anonymous surveys were conducted.Results:The study group performed better than the 'control' group with a significantly higher average score for the group scenario task-based test score,and consequently the study group's final course score was significantly higher than the 'control' group.As per chi-square tests,no significant associations were found between the multiple choice scores and the simulated training scores.The final surveys showed students overwhelmingly agreed that STS training improved their knowledge and skills,their ability to recognize a potential critical event, and their initial response for trauma care at pre-hospital settings.The survey responses of the study group were noteworthy as they indicated that students recognized the importance of simulative training,appreciated the realism of the simulation,and were able to fight/adjust to the stressful feelings in order to focus on the task.Conclusion:Computer-based STS may be an effective teaching model to help students improve their capability in providing pre-hospital trauma care,and in their effectiveness in disaster response.
文摘Computer simulation was used for hydraulic lifting systems. Based on theoryof multiphase flows and their applications on the lifting systems, mathematical models for pumplifting and air lifting were built and simulative analysis programs for them were developedrespectively. Corresponding lifting behaviors and system parameters were analyzed and optimum matchof the parameters for future pilot mining tests and commercial mining production was predicted.
基金supported by the National Key R&D Program of China(No.2022YFC2803900)the National Natural Science Foundation of China(No.42276191)Zhejiang University Students Science and Technology Innovation Activity Plan(New Talent Plan)(No.2024R401185).
文摘The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model.To address the limitations of traditional methods in obtaining high-quality sediment,a novel sampling system with 6000 m operational capability and three-month endurance was developed.It is equipped with three sediment samplers,a set of formaldehyde preservation solution injection devices.The system is controlled by a low-power,timing-triggered controllers.To investigate low-disturbance rheological mechanisms,gap controlled rheological tests were conducted to optimize the structural design of the sampling and sealing assembly.Stress-controlled shear rheological tests were employed to investigate the mechanisms governing yield stress in sediments under varying temperature conditions and boundary roughness.Additionally,the coupled Eulerian-Lagrangian(CEL)method and sediment rheological constitutive models were employed to simulate tube-soil interaction dynamics and sediment disturbance.The radial heterogeneity of sediment disturbance and friction variation of the sampling tube were revealed.The tube was completely“plugged”at a penetration depth of 261 mm,providing critical data support to the penetration depth parameters.The deep-sea pressure test and South China Sea field trials demonstrated the system’s capability to collect and preserve quantitative time-series sediment samples with high fidelity.
基金supported by the National Natural Science Foundation of China(62475008,62305186).
文摘Two-photon fluorescence microscopy,based on the principles of two-photon excited fluorescence and second harmonic generation,enables real-time non-invasive in vivo imaging of skin and cells,providing a means to assess human health status.In this paper,a miniaturized two-photon imaging system is designed and fabricated to withstand extreme vibration and shock environments.The mechanical stability of the optical and structural components of the miniaturized probe is evaluated under random vibration and shock vibration tests using finite element simulation methods and ray tracing techniques.During the environmental testing,the maximum stress on the probe is 11.5 MPa,which is well below the threshold for structural failure.The largest structural displacement occurs at the collimator,where random vibrations produce an offset of 10.9μm.This offset is analyzed by using geometric optics and point spread functions.Under the maximum collimator offset,the theoretical resolution,as calculated by the point spread function,shifted from 463.28 nm to 463.48 nm.Additionally,a lateral offset of 127 nm is observed at the center position,which does not significantly impact the imaging performance.Finally,environmental and imaging performance tests are conducted.The system’s measured resolution after the environmental tests is 530 nm,consistent with its resolution prior to testing.Imaging tests are also performed on the skin’s stratum corneum,granular layer,spinous layer,and basal cell layer,revealing clear cellular structural information.These results confirm the device’s potential for applications in extreme shock and vibration environments.
文摘Background:This article examines the impact of the release of Wolbachia-infected population replacement mosquitoes as an innovative strategy for managing and controlling dengue in the Americas,using an approach based on the system dynamics methodology.The introduction of Wolbachia-carrying mosquitoes aims to reduce dengue transmission by interfering with the reproductive capacity of mosquitoes,thus limiting the spread of the virus.Objective:the objective of this study is to analyze how this intervention affects not only the incidence of dengue but also the health care system,evaluating changes in the demand for medical services and the costs associated with treatment in health care institutions.Specifically,it looks at the cost per visit to an Epidemiologist,a Family Doctor,diagnostic tests,and hospitalization.Methods:the study uses simulation scenarios to model the potential impact of the Wolbachia-based intervention in reducing dengue cases and its associated health and economic burden.The scenarios also assess the optimization of resources and improvements in the health system’s response to epidemic outbreaks.The simulation model utilizes real data from the Americas region to enhance the accuracy and relevance of the results.Conclusion:The results the potential of the release of Wolbachia-carrying mosquitoes to significantly mitigate the health and economic burden of dengue,with a maximum saving of 60.15%in the best simulation scenario.The approach not only highlights scientific innovation but also demonstrates its potential influence on public policy design.The findings support the implementation of sustainable strategies to maximize the benefits of this intervention and ensure its effective integration into public health programs,contributing to better long-term dengue management.
基金support by the National Science and Technology Council under Grant No.NSTC 112-2221-E-167-017-MY3.
文摘Heating,Ventilation,andAir Conditioning(HVAC)systems are critical formaintaining thermal comfort in office environments which also crucial for occupant well-being and productivity.This study investigates the impact of integrating ceiling fans with higher air conditioning setpoints on thermal comfort and energy efficiency in office environments.Field measurements and questionnaire surveys were conducted to evaluate thermal comfort and energysaving potential under varying conditions.Results show that increasing the AC setpoint from 25○C to 27○C,combined with ceiling fan operation,reduced power consumption by 10%,achieving significant energy savings.Survey data confirmed that 85%of participants reported consistent thermal sensations across all conditions,with ceiling fans effectively compensating for higher setpoints through enhanced air circulation.CFDsimulations revealed that mediumspeed ceiling fan operation produced the most uniformairflowdistribution,with an average air velocity of 0.45 m/s,and minimized temperature variations,ensuring balanced thermal conditions.Temperature analysis showed a reduction in hotspots and cold zones,maintaining an average temperature deviation of less than±0.5○C.Predicted Mean Vote(PMV)evaluations at a 27○C setpoint indicated improved thermal comfort,with average PMV values around−0.3,corresponding to a“neutral”thermal sensation.These findings demonstrate the effectiveness of integrating ceiling fans with HVAC systems in achieving energy efficiency and occupant comfort,offering a sustainable approach to reducing AC energy consumption in office environments.
基金supported by the Anesthesiology Department Teaching Development Foundation of Naval Medical University under grant(2024MZQN02 and 2024MZQN03).
文摘This study addresses the limitations of traditional disaster medicine course assessments,including single evaluation formats,delayed feedback mechanisms,and gaps in competency mapping,by developing a diversified assessment system leveraging the Rain Classroom platform.The system incorporates six interconnected evaluation components across the learning cycle:pre-class preparation,pre-class tests,case discussions,skills assessment,post-class tests,and post-class feedback,collectively forming a three-dimensional“cognitive-skill-attitude”assessment framework.In the assessment design,the weighting of practical skill evaluation is elevated to 40%to prioritize the development of students’disaster response competencies.Additionally,an innovative multi-subject evaluation model(“self-peer-teacher”)is implemented within disaster scenario simulations,utilizing standardized scoring rubrics.This methodology not only enables comprehensive performance evaluation but also fosters critical teamwork and reflective practice.Implementation outcomes demonstrated that the system effectively evaluates learning progress through multi-modal assessments,enhances disaster rescue knowledge and skill proficiency,and successfully achieves predefined pedagogical objectives.
基金sponsored by the Science and Technology Foundation of Guizhou Provincial Education Department(No.QJJ[2024]60)Guizhou Provincial Basic Research Program(Natural Science)(No.QKHJC[2024]Youth 214)+1 种基金Science and Technology Foundation of Guizhou Minzu University(No.GZMUZK[2024]QD21)Research Projects of Anshun University(No.asxybsjj202413).
文摘To explore atomic-level phenomena in the Cu-Ni-Sn alloy,a second nearest-neighbor modified embedded-atom method(2NN MEAM)potential has been developed for the Cu-Ni-Sn system,building upon the work of other researchers.This potential demonstrates remarkable accuracy in predicting the lattice constant,with a relative error of less than 0.5%when compared to density functional theory(DFT)results,and it achieves a 10%relative error in the enthalpy of formation compared to experimental data,marking substantial advancements over prior models.The bulk modulus is predicted with a relative error of 8%compared to DFT.Notably,the potential effectively simulates the processes of melting and solidification of Cu-15Ni-8Sn,with a simulated melting point that closely aligns with the experimental value,within a 7.5%margin.This serves as a foundation for establishing a 2NN MEAM potential for a flawless Cu-Ni-Sn system and its microalloying systems.
基金supported by the National Natural Science Foundation of China(No.12372049)the Independent Project of State Key Laboratory of Rail Transit Vehicle System(No.2025RVL-QY-T24),China.
文摘Variable air volume systems are widely used in trains as they provide effective energy savings for air conditioning.However,the design phase is usually carried out at a certain fixed airflow,resulting in a difference between the expected and actual flow fields.In this study,we first analyzed the flow field characteristics at variable airflow rates under isothermal conditions,and subsequently established a correlation equation between the airflow and the flow field parameters.The results show that the airflow just entering the compartment conforms to the characteristics of an attached jet,and then,after converging in the middle,conforms to the characteristics of a free jet.The flow field characteristics are significantly correlated with the Reynolds number(Re)and are limited by the small space inside the vehicle.When Re≥2650,the axial velocities all conform to the classical u_(m)/u_(0)−(x/b)^(r) or u_(m)/u_(0)−(y/b)^(r) law,the sectional velocities conform to the exponential and Gaussian distributions,and the characteristic thicknesses of the jets conform to a linear distribution.Derivation shows that the entrainment suction flow rate is related mainly to the initial flow rate and the air opening width.The results of this study will inform the design of ventilation systems for high-speed trains.
基金funding from the National Natural Science Foundation of China(No.12462028).
文摘This study employs the Smoothed Particle Hydrodynamics(SPH)method to develop a computational fluid dynamics(CFD)model for analyzing the interaction between rogue waves and mooring systems.Four floating body configurations are investigated:(1)dual rectangular prisms,(2)rectangular prism–sphere composites,(3)sphere–rectangular prism composites,and(4)dual spheres.These configurations are systematically evaluated under varying mooring conditions to assess their hydrodynamic performance and wave attenuation capabilities.The model accurately captures the complex fluid–structure interaction dynamics between moored floating breakwaters and incident wave fields.Among the configurations,the dual rectangular prism system demonstrates superior performance in both wave dissipation and mooring force reduction.Under conditions involving dual wave makers,the influence of floating body shape and number on wave height is found to be minimal.However,dual-body arrangements consistently outperform single-body setups in terms of both energy dissipation and structural stability.From a cost-efficiency perspective,the configuration comprising two rectangular prisms connected via a single mooring system offers significant advantages in material usage and deployment feasibility.
基金the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineeringfinanced by the Portuguese Foundation for Science and Technology (Fundacao para a Ciência e Tecnologia-FCT) under contract UIDB/UIDP/00134/2020。
文摘A state-of-the-art review is presented of mathematical manoeuvring models for surface ships and parameter estimation methods that have been used to build mathematical manoeuvring models for surface ships. In the first part, the classical manoeuvring models, such as the Abkowitz model, MMG, Nomoto and their revised versions, are revisited and the model structure with the hydrodynamic coefficients is also presented.Then, manoeuvring tests, including both the scaled model tests and sea trials, are introduced with the fact that the test data is critically important to obtain reliable results using parameter estimation methods. In the last part, selected papers published in journals and international conferences are reviewed and the statistical analysis of the manoeuvring models, test data, system identification methods and environmental disturbances used in the paper is presented.
基金supported by National Natural Science Foundation of China(No.11975261)。
文摘In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.
基金supported by the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone(No.HZQB-KCZYB-2020083).
文摘Traditionally,a continuous-wave(CW)signal is used to simulate RF circuits during the design procedure,while the fabricated circuits are measured by modulated signals in the test phase,because modulated signals are used in reality.It is almost impossible to use a CW signal to predict system performances,such as error vector magnitude(EVM),bit error rate(BER),etc.,of a transceiver front-end when dealing with complex modulated signals.This paper develops an integrated system evaluation engine(ISEE)to evaluate the system performances of a transceiver front-end or its sub-circuits.This crossdomain simulation platform is based on Matlab,advanced design system(ADS),and Cadence simulators to link the baseband signals and transceiver frond-end.An orthogonal frequency division multiplex(OFDM)modem is implemented in Matlab for evaluating the system performances.The modulated baseband signal from Matlab is dynamically fed into ADS,which includes transceiver front-end for co-simulation.The sub-block circuits of the transceiver front-end can be implemented using ADS and Cadence simulators.After system-level circuit simulation in ADS,the output signal is dynamically delivered to Matlab for demodulation.To simplify the use of the co-simulation platform,a graphical user interface(GUI)is constructed using Matlab.The parameters of the OFDM signals can be easily reconfigured on the GUI to simulate RF circuits with different modulation schemes.To demonstrate the effectiveness of the ISEE,a 3.5 GHz power amplifier is simulated and characterized using 20 MHz 16-and 64-QAM OFDM signals.
基金supported in part by the Doctoral Initiation Fund of Nanchang Hangkong University(No.EA202403107)Jiangxi Province Early Career Youth Science and Technology Talent Training Project(No.CK202403509).
文摘This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.
