The Monte Carlo study evaluates the relative accuracy of Warm's (1989) weighted likelihood estimate (WLE) compared to the maximum likelihood estimate (MLE) using the nominal response model. And the results indi...The Monte Carlo study evaluates the relative accuracy of Warm's (1989) weighted likelihood estimate (WLE) compared to the maximum likelihood estimate (MLE) using the nominal response model. And the results indicate that WLE was more accurate than MLE.展开更多
There are certain limitations in the application of uncooled focal plane array (FPA) detector due to the lack of an effective response model which reliably transforms the target temperature to analog output voltage....There are certain limitations in the application of uncooled focal plane array (FPA) detector due to the lack of an effective response model which reliably transforms the target temperature to analog output voltage. This paper establishes the response model of microbolometer through researching the detection theory of microbolometer and the heat balance equation under the condition of the pulsed voltage bias. In the establishing process, we simplified the heat balance equation to acquire a simple answer. The experimental data show that, in the temperature dynamic range of 30 K, the biggest tolerance between the model data and the experiment data is 0.2 K; while in the temperature dynamic range of 100 K, it is 1 K. This model can reflect the real response of the microbolometer with only small differences which are acceptable in engineering applications.展开更多
This article describes the development and application of a streamlined air control and response modeling system with a novel response surface modeling-linear coupled fitting method and a new module to provide streaml...This article describes the development and application of a streamlined air control and response modeling system with a novel response surface modeling-linear coupled fitting method and a new module to provide streamlined model data for PM_(2.5) attainment assessment in China.This method is capable of significantly reducing the dimensions required to establish a response surface model,as well as capturing more realistic response of PM_(2.5) to emission changes with a limited number of model simulations.The newly developed module establishes a data link between the system and the Software for Model Attainment Test—Community Edition(SMAT-CE),and has the ability to rapidly provide model responses to emission control scenarios for SMAT-CE using a simple interface.The performance of this streamlined system is demonstrated through a case study of the Yangtze River Delta(YRD) in China.Our results show that this system is capable of reproducing the Community Multi-Scale Air Quality(CMAQ) model simulation results with maximum mean normalized error 〈 3.5%.It is also demonstrated that primary emissions make a major contribution to ambient levels of PM_(2.5) in January and August(e.g.,more than50%contributed by primary emissions in Shanghai),and Shanghai needs to have regional emission control both locally and in its neighboring provinces to meet China's annual PM_(2.5)National Ambient Air Quality Standard.The streamlined system provides a real-time control/response assessment to identify the contributions of major emission sources to ambient PM_(2.5)(and potentially O_3 as well) and streamline air quality data for SMAT-CE to perform attainment assessments.展开更多
Neurodevelopmental disorders are a group of conditions classified together by the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders which include intellectual disability,communication di...Neurodevelopmental disorders are a group of conditions classified together by the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders which include intellectual disability,communication disorders,autism spectrum disorder,attention-deficit/hyperactivity disorder,specific learning disorder(SLD),and motor disorders.SLD is present in many students,who exhibit significant difficulties in the acquisition of reading,written expression,and mathematics,mostly due to problems with executive functions(EF).The present study is a review of the current situation of neurodevelopmental disorders and SLD focusing on the benefits of the response to intervention model(RtI),which allows the combination of evaluation and intervention processes.It also addresses the key role of EF.The importance of adapting RtI to new possibilities such as the use of virtual reality is discussed and a theoretical framework for carrying that out is provided.展开更多
Agents response equilibrium (ARE) model has been taken advantage of to build a multi-agent system for analyzing fiscal policy effect. Through establishing various types of economic entities and endowing them with abil...Agents response equilibrium (ARE) model has been taken advantage of to build a multi-agent system for analyzing fiscal policy effect. Through establishing various types of economic entities and endowing them with abilities to react and make decision, the whole system will evolve to new conditions in response to policy change. Compared with different scenarios, it can be concluded that when raising taxation ratio, sectoral scale will shrink to some extent. But supported by government expenditure, certain sectors could be kept in comparatively larger production scale.展开更多
Based on the scale-free network, an integrated systemic inflammatory response syndrome model with artificial immunity, a feedback mechanism, crowd density and the moving activities of an individual can be built. The e...Based on the scale-free network, an integrated systemic inflammatory response syndrome model with artificial immunity, a feedback mechanism, crowd density and the moving activities of an individual can be built. The effects of these factors on the spreading process are investigated through the model. The research results show that the artificial immunity can reduce the stable infection ratio and enhance the spreading threshold of the system. The feedback mechanism can only reduce the stable infection ratio of system, but cannot affect the spreading threshold of the system. The bigger the crowd density is, the higher the infection ratio of the system is and the smaller the spreading threshold is. In addition, the simulations show that the individual movement can enhance the stable infection ratio of the system only under the condition that the spreading rate is high, however, individual movement will reduce the stable infection ratio of the system.展开更多
On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the...On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the time scale of the response is not only related to the rate of wave growth, but also to the directional energy distribution and the angle between the wind direction and the mean wave direction. Furthermore, the law of change in the mean wave direction has been derived. The numerical computations show that the response of wave directions to slowly turning wind directions can be treated as the superposition of the responses of wave directions to a series of sudden small-angle changes of wind directions and the turning rate of the mean wave direction depends on the turning rate and the total turning angles of the wind direction. The response of wave directions is in agreement with the response for a sudden change of wind directions if the change in wind directions is very fast. Based on the normalized rates of wave growth under local winds presented by Wen et al. (1989), a quantitative estimate of the time scale of the response shows that the relationships between the dimensionless time scale and both the dimensionless total wave energy and the dimensionless peak frequency agree fairly well with the observations in comparison with other models.展开更多
To understand and develop new nanostructure materials with specific mechanical properties, a good knowledge of the elastic strain response is mandatory. Here we investigate the linear elasticity response in the modifi...To understand and develop new nanostructure materials with specific mechanical properties, a good knowledge of the elastic strain response is mandatory. Here we investigate the linear elasticity response in the modified phase-field-crystal(MPFC) model. The results show that two different propagation modes control the elastic interaction length and time, which determine whether the density waves can propagate or not. By quantitatively calculating the strain field, we find that the strain distribution is indeed extremely uniform in case of elasticity. Further, we present a detailed theoretical analysis for the orientation dependence and temperature dependence of shear modulus. The simulation results show that the shear modulus reveals strong anisotropy and the one-mode analysis provides a good guideline for determining elastic shear constants until the system temperature falls below a certain value.展开更多
Ocean response to atmospheric forcing in the CZ ocean model is analyzed.The results show that Nino 3 indexfrom the CZ ocean model driven by linear composite of biennial,ENSO and even annual time scale wind stressanoma...Ocean response to atmospheric forcing in the CZ ocean model is analyzed.The results show that Nino 3 indexfrom the CZ ocean model driven by linear composite of biennial,ENSO and even annual time scale wind stressanomalies is consistent well with composite of responding two or three components of observed Nino 3 index duringthe EI Nino period while the La Nina phenomena cannot be reproduced by the linear composite.It implies that linearresponse process for ocean response to atmospheric forcing is dominated during the EI Nino period while nonlinearresponse might be main process during the La Nina period.Simulated results also suggest that optimal response frequency of the CZ ocean model is the frequency lowerthan annual variability and ocean response to the atmospheric forcing with annual time scale can give rise to incorrectsignal-errors in the simulated SSTA field.展开更多
[Objectives]This study was conducted to investigate the differences of photosynthetic physiological characteristics of different varieties(strains),which will provide a theoretical basis for high photosynthesis effici...[Objectives]This study was conducted to investigate the differences of photosynthetic physiological characteristics of different varieties(strains),which will provide a theoretical basis for high photosynthesis efficiency breeding and application in Chinese chestnut.[Methods]Six Chinese chestnut varieties of Castanea mollissima‘Yanbao’,C.mollissima‘Yanqiu’,C.mollissima‘Yanchang’,C.mollissima‘Yanjia’,C.mollissima‘Qianxi 37’,and C.mollissima‘Hybrid 22’were used as the materials.Using the portable photosynthesis system Li-6400,we measured the photosynthetic characteristics and diurnal variation of leaf samples of six different chestnut varieties or strains.We fitted the light response curves and photosynthetic parameters using the leaf floating model.Additionally,we determined the chlorophyll content in the leaves using a UV-visible spectrophotometer.[Results]Among the six chestnut varieties or strains,‘Yanqiu’exhibited a significantly higher photosynthetic light saturation point(P LSP)compared to other five varieties,and‘Hybrid 22’ranked second,indicating that these two varieties had the strongest adaptation to high light intensity.The photosynthetic light compensation point(P LCP)of‘Yanchang’was significantly higher than other five varieties,and"Qianxi 37"ranked second,indicating that these two varieties had the strongest adaptation to low light intensity.Additionally,they exhibited higher chlorophyll content and maintained good photosynthetic characteristics even in shaded environments with weak light stress.Varieties‘Yanbao’and‘Yanjia’showed higher P LSP and lower P LCP,indicating that these two varieties have a wider range of adaptation to light intensity.They were capable of efficiently utilizing light across a broader spectrum of intensities.‘Yanqiu’had the highest maximum net photosynthetic rate(P n,max)and the lowest dark respiration rate(R d),along with the highest chlorophyll content.It indicated that‘Yanqiu’has strong photosynthetic capacity and organic matter accumulation ability.It also had the highest P LSP,enabling it to fully utilize the high light environment of the Yanshan Mountains and possessed high light efficiency characteristics.The P n,max of‘Yanqiu’was significantly higher than other varieties.‘Hybrid 22’and‘Yanbao’also exhibited significantly higher P n,max compared with‘Yanjia’and‘Qianxi 37’.‘Yanchang’had the lowest P n,max.The order of P n,max among the six chestnut varieties or strains was as follows:‘Yanqiu’>‘Hybrid 22’>‘Yanbao’>‘Yanjia’>‘Qianxi 37’>‘Yanchang’.[Conclusions]展开更多
A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion m...A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion model to simulate the pollutant concentration through consideration of the influence of urban buildings. Numerical experiments are designed to evaluate the model's performance, using CEDVAL (Compilation of Experimental Data for Validation of Microscale Disper- sion Models) wind tunnel experiment data, including wind fields and air pollutant dispersion around a single building. The results show that the wind model can reproduce the vortexes triggered by urban buildings and the dispersion model simulates the pollutant concentration around buildings well. Typically, the simulation errors come from the determination of the key zones around a building or building cluster. This model has the potential for multiple applications; for example, the prediction of air pollutant dispersion and the evaluation of environmental impacts in emergency situations; urban planning scenarios; and the assessment of microscale air quality in urban areas.展开更多
The simulation performance over complex building clusters of a wind simulation model(Wind Information Field Fast Analysis model, WIFFA) in a micro-scale air pollutant dispersion model system(Urban Microscale Air Po...The simulation performance over complex building clusters of a wind simulation model(Wind Information Field Fast Analysis model, WIFFA) in a micro-scale air pollutant dispersion model system(Urban Microscale Air Pollution dispersion Simulation model, UMAPS) is evaluated using various wind tunnel experimental data including the CEDVAL(Compilation of Experimental Data for Validation of Micro-Scale Dispersion Models) wind tunnel experiment data and the NJU-FZ experiment data(Nanjing University-Fang Zhuang neighborhood wind tunnel experiment data). The results show that the wind model can reproduce the vortexes triggered by urban buildings well, and the flow patterns in urban street canyons and building clusters can also be represented. Due to the complex shapes of buildings and their distributions, the simulation deviations/discrepancies from the measurements are usually caused by the simplification of the building shapes and the determination of the key zone sizes. The computational efficiencies of different cases are also discussed in this paper. The model has a high computational efficiency compared to traditional numerical models that solve the Navier–Stokes equations, and can produce very high-resolution(1–5 m) wind fields of a complex neighborhood scale urban building canopy(~ 1 km ×1km) in less than 3 min when run on a personal computer.展开更多
The modern aircraft Thermal Management System(TMS)faces significant challenges due to increasing thermal loads and limited heat dissipation pathways.To optimize TMS during the conceptual design stage,the development o...The modern aircraft Thermal Management System(TMS)faces significant challenges due to increasing thermal loads and limited heat dissipation pathways.To optimize TMS during the conceptual design stage,the development of a modeling and simulation tool is crucial.In this study,a TMS simulation model library was created using MATLAB/SIMULINK.To simplify the complexity of the Vapor Cycle System(VCS)model,a Response Surface Model(RSM)was constructed using the Monte Carlo method and validated through simulation experiments.Taking the F-22 fighter TMS as an example,a thermal dynamic simulation model was constructed to analyze the variation of thermal response parameters in key subsystems and elucidate their coupling relationships.Furthermore,the impact of total fuel flow and ram air flow on the TMS was investigated.The findings demonstrate the existence of an optimal total fuel flow that achieves a balance between maximizing fuel heat sink utilization and minimizing bleed air demand.The adaptive distribution of fuel and ram air flow was found to enhance aircraft thermal management performance.This study contributes to improving modeling efficiency and enhancing the understanding of the thermal dynamic characteristics of TMS,thereby facilitating further optimization in aircraft TMS design.展开更多
Based upon the studies of solutional rates with environment from South China to North China over a range of about 30 。 latitude, this paper discusses some of the consequence with equations. The response model shows ...Based upon the studies of solutional rates with environment from South China to North China over a range of about 30 。 latitude, this paper discusses some of the consequence with equations. The response model shows that the precipitation is the most important factor influencing the rate of solutional denudation except the lithology, the relief etc., but it is an integrational action on the solution process; at the same time, temperature acts as a threshold in bringing the precipitation into play. These suggest that firstly, the solutional denudation process is a comprehensive response to the multiple factors; secondly, karst solution is a complex response process to the climate, and as an integrated exogenic process under the bioclimate.展开更多
Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity ana...Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on (1) a screening method (Morris) for qualitative ranking of parameters, and (2) a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model (RSMSobol). First, the Morris screening method was used to qualitatively identify the parameters' sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model (RSM) were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.展开更多
A model based on the data from forced vibration experiments is developed for predicting the vortex-induced vibra- tions (VIV) of elastically mounted circular cylinders in flow. The assumptions for free and forced vi...A model based on the data from forced vibration experiments is developed for predicting the vortex-induced vibra- tions (VIV) of elastically mounted circular cylinders in flow. The assumptions for free and forced vibration tests are explored briefly. Energy equilibrium is taken into account to set up the relationship between the dynamic response of selfexcited oscillations and the force coemcients from forced vibration experiments. The gap between these two cases is bridged straightforwardly with careful treatment of key parameters. Given reduced mass m^# and material damping ratio of an elastically mounted circular cylinder in flow, the response characteristics such as amplitude, frequency, lock-in range, added mass coefficient, cross-flow fluid force and the corresponding phase angle can be predicted all at once. In- stances with different combination of reduced mass and material damping ratio are compared to investigate their effects on VIV. The hysteresis phenomenon can be interpreted reasonably. The predictions and the results from recent experiments carried out by Wifliamson' s group are in rather good agreement.展开更多
Optimization studies of plasma smelting of red mud were carried out. Reduction of the dried red mud fines was done in an extended arc plasma reactor to recover the pig iron. Lime grit and low ash metallurgical (LAM)...Optimization studies of plasma smelting of red mud were carried out. Reduction of the dried red mud fines was done in an extended arc plasma reactor to recover the pig iron. Lime grit and low ash metallurgical (LAM) coke were used as the flux and reductant, respectively. 2level factorial design was used to study the influence of all parameters on the responses. Response surface modeling was done with the data obtained from statistically designed experiments. Metal recovery at optimum parameters was found to be 79.52%.展开更多
To investigate the application of meta-model for finite element( FE) model updating of structures,the performance of two popular meta-model,i. e.,Kriging model and response surface model( RSM),were compared in detail....To investigate the application of meta-model for finite element( FE) model updating of structures,the performance of two popular meta-model,i. e.,Kriging model and response surface model( RSM),were compared in detail. Firstly,above two kinds of meta-model were introduced briefly. Secondly,some key issues of the application of meta-model to FE model updating of structures were proposed and discussed,and then some advices were presented in order to select a reasonable meta-model for the purpose of updating the FE model of structures. Finally,the procedure of FE model updating based on meta-model was implemented by updating the FE model of a truss bridge model with the measured modal parameters. The results showed that the Kriging model was more proper for FE model updating of complex structures.展开更多
Thin wail component is utilized to absorb impact energy of a structure. However, the dynamic behavior of such thin-walled structure is highly non-linear with material, geometry and boundary non-linearity. A model upda...Thin wail component is utilized to absorb impact energy of a structure. However, the dynamic behavior of such thin-walled structure is highly non-linear with material, geometry and boundary non-linearity. A model updating and validation procedure is proposed to build accurate finite element model of a frame structure with a non-linear thin-walled component for dynamic analysis. Design of experiments (DOE) and principal component decomposition (PCD) approach are applied to extract dynamic feature from nonlinear impact response for correlation of impact test result and FE model of the non-linear structure. A strain-rate-dependent non-linear model updating method is then developed to build accurate FE model of the structure. Computer simulation and a real frame structure with a highly non-linear thin-walled component are employed to demonstrate the feasibility and effectiveness of the proposed approach.展开更多
文摘The Monte Carlo study evaluates the relative accuracy of Warm's (1989) weighted likelihood estimate (WLE) compared to the maximum likelihood estimate (MLE) using the nominal response model. And the results indicate that WLE was more accurate than MLE.
基金Project supported by the National Defense Pre-research Fund of China (Grant No. 50405050303)the Natural Science Foundation of Jiangsu Province of China (Grant No. BK2009049)
文摘There are certain limitations in the application of uncooled focal plane array (FPA) detector due to the lack of an effective response model which reliably transforms the target temperature to analog output voltage. This paper establishes the response model of microbolometer through researching the detection theory of microbolometer and the heat balance equation under the condition of the pulsed voltage bias. In the establishing process, we simplified the heat balance equation to acquire a simple answer. The experimental data show that, in the temperature dynamic range of 30 K, the biggest tolerance between the model data and the experiment data is 0.2 K; while in the temperature dynamic range of 100 K, it is 1 K. This model can reflect the real response of the microbolometer with only small differences which are acceptable in engineering applications.
基金Financial support and data source for this work is provided by the US Environmental Protection Agency(No.OR13810-001.04 A10-0223-S001-A02)Guangzhou Environmental Protection Bureau(No.x2hj B2150020)+4 种基金the project of an integrated modeling and filed observational verification on the deposition of typical industrial point-source mercury emissions in the Pearl River Deltapartly supported by the funding of Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control(No.2011A060901011)the project of Atmospheric Haze Collaboration Control Technology Design(No.XDB05030400)from the Chinese Academy of Sciencesthe Ministry of Environmental Protection's Special Funds for Research on Public Welfare(No.201409002)Partly financial support is also provided by the Guangdong Provincial Department of Science and Technology,the project of demonstration research of air quality management cost-benefit analysis and attainment assessments technology(No.2014A050503019)
文摘This article describes the development and application of a streamlined air control and response modeling system with a novel response surface modeling-linear coupled fitting method and a new module to provide streamlined model data for PM_(2.5) attainment assessment in China.This method is capable of significantly reducing the dimensions required to establish a response surface model,as well as capturing more realistic response of PM_(2.5) to emission changes with a limited number of model simulations.The newly developed module establishes a data link between the system and the Software for Model Attainment Test—Community Edition(SMAT-CE),and has the ability to rapidly provide model responses to emission control scenarios for SMAT-CE using a simple interface.The performance of this streamlined system is demonstrated through a case study of the Yangtze River Delta(YRD) in China.Our results show that this system is capable of reproducing the Community Multi-Scale Air Quality(CMAQ) model simulation results with maximum mean normalized error 〈 3.5%.It is also demonstrated that primary emissions make a major contribution to ambient levels of PM_(2.5) in January and August(e.g.,more than50%contributed by primary emissions in Shanghai),and Shanghai needs to have regional emission control both locally and in its neighboring provinces to meet China's annual PM_(2.5)National Ambient Air Quality Standard.The streamlined system provides a real-time control/response assessment to identify the contributions of major emission sources to ambient PM_(2.5)(and potentially O_3 as well) and streamline air quality data for SMAT-CE to perform attainment assessments.
基金Supported by Ministry of Sciences and Innovation I+D+i Project,No.PID2019-107201GB-100Principality of Asturias,No.FCGRUPIN-IDI/2018/000199.
文摘Neurodevelopmental disorders are a group of conditions classified together by the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders which include intellectual disability,communication disorders,autism spectrum disorder,attention-deficit/hyperactivity disorder,specific learning disorder(SLD),and motor disorders.SLD is present in many students,who exhibit significant difficulties in the acquisition of reading,written expression,and mathematics,mostly due to problems with executive functions(EF).The present study is a review of the current situation of neurodevelopmental disorders and SLD focusing on the benefits of the response to intervention model(RtI),which allows the combination of evaluation and intervention processes.It also addresses the key role of EF.The importance of adapting RtI to new possibilities such as the use of virtual reality is discussed and a theoretical framework for carrying that out is provided.
文摘Agents response equilibrium (ARE) model has been taken advantage of to build a multi-agent system for analyzing fiscal policy effect. Through establishing various types of economic entities and endowing them with abilities to react and make decision, the whole system will evolve to new conditions in response to policy change. Compared with different scenarios, it can be concluded that when raising taxation ratio, sectoral scale will shrink to some extent. But supported by government expenditure, certain sectors could be kept in comparatively larger production scale.
基金Project supported by the Natural Science Foundation of the Education Department of Guizhou Province,China (Grant No.20090133)International Cooperative Foundation of Guizhou Province,China (Grant No.20117007)
文摘Based on the scale-free network, an integrated systemic inflammatory response syndrome model with artificial immunity, a feedback mechanism, crowd density and the moving activities of an individual can be built. The effects of these factors on the spreading process are investigated through the model. The research results show that the artificial immunity can reduce the stable infection ratio and enhance the spreading threshold of the system. The feedback mechanism can only reduce the stable infection ratio of system, but cannot affect the spreading threshold of the system. The bigger the crowd density is, the higher the infection ratio of the system is and the smaller the spreading threshold is. In addition, the simulations show that the individual movement can enhance the stable infection ratio of the system only under the condition that the spreading rate is high, however, individual movement will reduce the stable infection ratio of the system.
文摘On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the time scale of the response is not only related to the rate of wave growth, but also to the directional energy distribution and the angle between the wind direction and the mean wave direction. Furthermore, the law of change in the mean wave direction has been derived. The numerical computations show that the response of wave directions to slowly turning wind directions can be treated as the superposition of the responses of wave directions to a series of sudden small-angle changes of wind directions and the turning rate of the mean wave direction depends on the turning rate and the total turning angles of the wind direction. The response of wave directions is in agreement with the response for a sudden change of wind directions if the change in wind directions is very fast. Based on the normalized rates of wave growth under local winds presented by Wen et al. (1989), a quantitative estimate of the time scale of the response shows that the relationships between the dimensionless time scale and both the dimensionless total wave energy and the dimensionless peak frequency agree fairly well with the observations in comparison with other models.
基金Project supported by the National Natural Science foundation of China(Grant Nos.51571165 and 51371151)Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase),Chinathe Fundamental Research Funds for the Central Universities,China(Grant No.3102015BJ(II)ZS001)
文摘To understand and develop new nanostructure materials with specific mechanical properties, a good knowledge of the elastic strain response is mandatory. Here we investigate the linear elasticity response in the modified phase-field-crystal(MPFC) model. The results show that two different propagation modes control the elastic interaction length and time, which determine whether the density waves can propagate or not. By quantitatively calculating the strain field, we find that the strain distribution is indeed extremely uniform in case of elasticity. Further, we present a detailed theoretical analysis for the orientation dependence and temperature dependence of shear modulus. The simulation results show that the shear modulus reveals strong anisotropy and the one-mode analysis provides a good guideline for determining elastic shear constants until the system temperature falls below a certain value.
文摘Ocean response to atmospheric forcing in the CZ ocean model is analyzed.The results show that Nino 3 indexfrom the CZ ocean model driven by linear composite of biennial,ENSO and even annual time scale wind stressanomalies is consistent well with composite of responding two or three components of observed Nino 3 index duringthe EI Nino period while the La Nina phenomena cannot be reproduced by the linear composite.It implies that linearresponse process for ocean response to atmospheric forcing is dominated during the EI Nino period while nonlinearresponse might be main process during the La Nina period.Simulated results also suggest that optimal response frequency of the CZ ocean model is the frequency lowerthan annual variability and ocean response to the atmospheric forcing with annual time scale can give rise to incorrectsignal-errors in the simulated SSTA field.
基金Supported by National Key R&D Program of China (2022YFD2200400)Doctoral Started Fund of Hebei Normal University of Science and Technology (2023YB026)Hebei Qinglong Chinese Chestnut Technological Yard.
文摘[Objectives]This study was conducted to investigate the differences of photosynthetic physiological characteristics of different varieties(strains),which will provide a theoretical basis for high photosynthesis efficiency breeding and application in Chinese chestnut.[Methods]Six Chinese chestnut varieties of Castanea mollissima‘Yanbao’,C.mollissima‘Yanqiu’,C.mollissima‘Yanchang’,C.mollissima‘Yanjia’,C.mollissima‘Qianxi 37’,and C.mollissima‘Hybrid 22’were used as the materials.Using the portable photosynthesis system Li-6400,we measured the photosynthetic characteristics and diurnal variation of leaf samples of six different chestnut varieties or strains.We fitted the light response curves and photosynthetic parameters using the leaf floating model.Additionally,we determined the chlorophyll content in the leaves using a UV-visible spectrophotometer.[Results]Among the six chestnut varieties or strains,‘Yanqiu’exhibited a significantly higher photosynthetic light saturation point(P LSP)compared to other five varieties,and‘Hybrid 22’ranked second,indicating that these two varieties had the strongest adaptation to high light intensity.The photosynthetic light compensation point(P LCP)of‘Yanchang’was significantly higher than other five varieties,and"Qianxi 37"ranked second,indicating that these two varieties had the strongest adaptation to low light intensity.Additionally,they exhibited higher chlorophyll content and maintained good photosynthetic characteristics even in shaded environments with weak light stress.Varieties‘Yanbao’and‘Yanjia’showed higher P LSP and lower P LCP,indicating that these two varieties have a wider range of adaptation to light intensity.They were capable of efficiently utilizing light across a broader spectrum of intensities.‘Yanqiu’had the highest maximum net photosynthetic rate(P n,max)and the lowest dark respiration rate(R d),along with the highest chlorophyll content.It indicated that‘Yanqiu’has strong photosynthetic capacity and organic matter accumulation ability.It also had the highest P LSP,enabling it to fully utilize the high light environment of the Yanshan Mountains and possessed high light efficiency characteristics.The P n,max of‘Yanqiu’was significantly higher than other varieties.‘Hybrid 22’and‘Yanbao’also exhibited significantly higher P n,max compared with‘Yanjia’and‘Qianxi 37’.‘Yanchang’had the lowest P n,max.The order of P n,max among the six chestnut varieties or strains was as follows:‘Yanqiu’>‘Hybrid 22’>‘Yanbao’>‘Yanjia’>‘Qianxi 37’>‘Yanchang’.[Conclusions]
基金supported by the National Natural Science Foundation of China (Grant No. 41375014)the National Basic Research Program of China (Grant No. 2011CB 952002)Jiangsu Collaborative Innovation Center for Climate Change, China
文摘A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion model to simulate the pollutant concentration through consideration of the influence of urban buildings. Numerical experiments are designed to evaluate the model's performance, using CEDVAL (Compilation of Experimental Data for Validation of Microscale Disper- sion Models) wind tunnel experiment data, including wind fields and air pollutant dispersion around a single building. The results show that the wind model can reproduce the vortexes triggered by urban buildings and the dispersion model simulates the pollutant concentration around buildings well. Typically, the simulation errors come from the determination of the key zones around a building or building cluster. This model has the potential for multiple applications; for example, the prediction of air pollutant dispersion and the evaluation of environmental impacts in emergency situations; urban planning scenarios; and the assessment of microscale air quality in urban areas.
基金supported by the China Special Fund for Meteorological Research in the Public Interest(Grant No.GYHY201106049)the National Natural Science Foundation of China(Grant Nos.51538005 and 41375014)the Jiangsu Collaborative Innovation Center for Climate Change,China
文摘The simulation performance over complex building clusters of a wind simulation model(Wind Information Field Fast Analysis model, WIFFA) in a micro-scale air pollutant dispersion model system(Urban Microscale Air Pollution dispersion Simulation model, UMAPS) is evaluated using various wind tunnel experimental data including the CEDVAL(Compilation of Experimental Data for Validation of Micro-Scale Dispersion Models) wind tunnel experiment data and the NJU-FZ experiment data(Nanjing University-Fang Zhuang neighborhood wind tunnel experiment data). The results show that the wind model can reproduce the vortexes triggered by urban buildings well, and the flow patterns in urban street canyons and building clusters can also be represented. Due to the complex shapes of buildings and their distributions, the simulation deviations/discrepancies from the measurements are usually caused by the simplification of the building shapes and the determination of the key zone sizes. The computational efficiencies of different cases are also discussed in this paper. The model has a high computational efficiency compared to traditional numerical models that solve the Navier–Stokes equations, and can produce very high-resolution(1–5 m) wind fields of a complex neighborhood scale urban building canopy(~ 1 km ×1km) in less than 3 min when run on a personal computer.
文摘The modern aircraft Thermal Management System(TMS)faces significant challenges due to increasing thermal loads and limited heat dissipation pathways.To optimize TMS during the conceptual design stage,the development of a modeling and simulation tool is crucial.In this study,a TMS simulation model library was created using MATLAB/SIMULINK.To simplify the complexity of the Vapor Cycle System(VCS)model,a Response Surface Model(RSM)was constructed using the Monte Carlo method and validated through simulation experiments.Taking the F-22 fighter TMS as an example,a thermal dynamic simulation model was constructed to analyze the variation of thermal response parameters in key subsystems and elucidate their coupling relationships.Furthermore,the impact of total fuel flow and ram air flow on the TMS was investigated.The findings demonstrate the existence of an optimal total fuel flow that achieves a balance between maximizing fuel heat sink utilization and minimizing bleed air demand.The adaptive distribution of fuel and ram air flow was found to enhance aircraft thermal management performance.This study contributes to improving modeling efficiency and enhancing the understanding of the thermal dynamic characteristics of TMS,thereby facilitating further optimization in aircraft TMS design.
文摘Based upon the studies of solutional rates with environment from South China to North China over a range of about 30 。 latitude, this paper discusses some of the consequence with equations. The response model shows that the precipitation is the most important factor influencing the rate of solutional denudation except the lithology, the relief etc., but it is an integrational action on the solution process; at the same time, temperature acts as a threshold in bringing the precipitation into play. These suggest that firstly, the solutional denudation process is a comprehensive response to the multiple factors; secondly, karst solution is a complex response process to the climate, and as an integrated exogenic process under the bioclimate.
基金supported by the National Natural Science Foundation of China (Grant No. 41271003)the National Basic Research Program of China (Grants No. 2010CB428403 and 2010CB951103)
文摘Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on (1) a screening method (Morris) for qualitative ranking of parameters, and (2) a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model (RSMSobol). First, the Morris screening method was used to qualitatively identify the parameters' sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model (RSM) were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.
基金This project was financially supported bythe National Natural Science Foundation of China ( Grant No50323004)a grant fromthe Science and Technology Commission of Shanghai Municipality (No05DJ14001)
文摘A model based on the data from forced vibration experiments is developed for predicting the vortex-induced vibra- tions (VIV) of elastically mounted circular cylinders in flow. The assumptions for free and forced vibration tests are explored briefly. Energy equilibrium is taken into account to set up the relationship between the dynamic response of selfexcited oscillations and the force coemcients from forced vibration experiments. The gap between these two cases is bridged straightforwardly with careful treatment of key parameters. Given reduced mass m^# and material damping ratio of an elastically mounted circular cylinder in flow, the response characteristics such as amplitude, frequency, lock-in range, added mass coefficient, cross-flow fluid force and the corresponding phase angle can be predicted all at once. In- stances with different combination of reduced mass and material damping ratio are compared to investigate their effects on VIV. The hysteresis phenomenon can be interpreted reasonably. The predictions and the results from recent experiments carried out by Wifliamson' s group are in rather good agreement.
基金Vedanta Alumina Ltd,a subsidiary of Vedanta Resources Plc for supporting the project financially
文摘Optimization studies of plasma smelting of red mud were carried out. Reduction of the dried red mud fines was done in an extended arc plasma reactor to recover the pig iron. Lime grit and low ash metallurgical (LAM) coke were used as the flux and reductant, respectively. 2level factorial design was used to study the influence of all parameters on the responses. Response surface modeling was done with the data obtained from statistically designed experiments. Metal recovery at optimum parameters was found to be 79.52%.
基金Sponsored by the National Key Technology Research and Development Program of China(Grant No.2011BAK02B02)
文摘To investigate the application of meta-model for finite element( FE) model updating of structures,the performance of two popular meta-model,i. e.,Kriging model and response surface model( RSM),were compared in detail. Firstly,above two kinds of meta-model were introduced briefly. Secondly,some key issues of the application of meta-model to FE model updating of structures were proposed and discussed,and then some advices were presented in order to select a reasonable meta-model for the purpose of updating the FE model of structures. Finally,the procedure of FE model updating based on meta-model was implemented by updating the FE model of a truss bridge model with the measured modal parameters. The results showed that the Kriging model was more proper for FE model updating of complex structures.
基金National Natural Science Foundation of China(No.50575101).
文摘Thin wail component is utilized to absorb impact energy of a structure. However, the dynamic behavior of such thin-walled structure is highly non-linear with material, geometry and boundary non-linearity. A model updating and validation procedure is proposed to build accurate finite element model of a frame structure with a non-linear thin-walled component for dynamic analysis. Design of experiments (DOE) and principal component decomposition (PCD) approach are applied to extract dynamic feature from nonlinear impact response for correlation of impact test result and FE model of the non-linear structure. A strain-rate-dependent non-linear model updating method is then developed to build accurate FE model of the structure. Computer simulation and a real frame structure with a highly non-linear thin-walled component are employed to demonstrate the feasibility and effectiveness of the proposed approach.