Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.C...Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.Current research on the associations between 24-hour movement behaviors(including physical activity,sedentary behavior,and sleep)and depression has largely been confined to examining the effects of single behaviors,overlooking the intrinsic compositional nature and interrelationships among these behaviors.Therefore,it is necessary to investigate the integrated effects of 24-hour movement behaviors on depression in older adults with multimorbidity from a holistic,compositional perspective.Methods:From November 2024 to April 2025,a total of 226 older adult patients with multimorbidity were recruited from a tertiary hospital in Changzhou City.Data were collected using a general information questionnaire,the International Physical Activity Questionnaire–Short Form(IPAQ-SF),the Pittsburgh Sleep Quality Index(PSQI),and the Patient Health Questionnaire-9(PHQ-9).Compositional data analysis and isotemporal substitution models were employed for statistical analysis.Results:The mean daily durations of Light-Intensity Physical Activity(LPA),Moderate-to-Vigorous Physical Activity(MVPA),Sedentary Behavior(SB),and Sleep(SLP)in older adults with multimorbidity were 402.48 min,12.04 min,511.52 min,and 458.68 min,respectively.The prevalence of depressive symptoms was 37.6%.Compositional data analysis revealed that SB was positively associated with depression(βSB=1.005,P=0.006),while SLP was negatively associated with depression(βSLP=−1.736,P<0.001).No statistically significant associations were found between MVPA or LPA and depression(P>0.05).In the 10-minute isotemporal substitution model,replacing SB with any other behavioral component was associated with a decrease in depression scores.Conversely,substituting SLP with either LPA or SB resulted in an increase in depression scores,while substituting SLP with MVPA led to a decrease in depression scores.The dose-response analysis revealed that,among the isotemporal substitution effects,replacing SB with SLP and replacing SLP with MVPA were the substitution pathways associated with the most rapid decline in depression scores,representing the greatest beneficial health effects.Conclusion:The prevalence of depression is notably high among older adults with multimorbidity.Reducing daily sedentary behavior(SB),maintaining adequate sleep(SLP),and increasing moderate-to-vigorous physical activity(MVPA)can improve depressive symptoms and enhance overall health in this population.展开更多
The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique natu...The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects.展开更多
One of the main objectives of artificial intelligence lies in the simulation of the behavior of living organisms;emotions are a fundamental part of life, and they cannot be left aside when simulating behavior. In this...One of the main objectives of artificial intelligence lies in the simulation of the behavior of living organisms;emotions are a fundamental part of life, and they cannot be left aside when simulating behavior. In this research, software is developed that simulates the behavior of birds with different characteristics. The latter interacts by considering different stimuli from the environment (external), and the internal state of the subject (objectives). To achieve this, a model of birds in the role of prey and predators is developed that focuses on the study of the interaction between these organisms that exhibit specific behaviors in their environment. This project is a seminal work that aims to represent the emotions of birds, and the latter caused by stimuli from a dynamic environment.展开更多
This work aims to investigate the thermo-poromechanical behavior of saturated silt clay(SC)under varying temperatures through experiments and constitutive modeling.A series of undrained triaxial compression tests was ...This work aims to investigate the thermo-poromechanical behavior of saturated silt clay(SC)under varying temperatures through experiments and constitutive modeling.A series of undrained triaxial compression tests was conducted on saturated SC with temperature ranges from 25℃to 60℃.The effects of temperature on the main poromechanical properties of saturated SC,such as stress-strain relations,pore pressure evolution,and strength parameters,were thoroughly examined.Based on the experimental results,a subtly thermodynamically consistent thermo-poromechanical model was established using the concept of effective plastic stress within the poromechanical framework.Plastic deformation was described with a specific yield criterion and non-associated plastic potential that both depend on the effective plastic stress and a simple hardening variable.Finally,this model was implemented by a semi-implicit return mapping algorithm(SRMA)and validated through the comparison of model predictions and experimental data.The proposed model accurately reproduces the main thermo-poromechanical characteristics observed in saturated SC.展开更多
In this study,nanoindentation techniques,macroscopic mechanical testing,and the Mori-Tanaka theoretical model are integrated to analyze the thermal‒mechanical behavior of granite systematically.The experimental result...In this study,nanoindentation techniques,macroscopic mechanical testing,and the Mori-Tanaka theoretical model are integrated to analyze the thermal‒mechanical behavior of granite systematically.The experimental results demonstrate that quartz and feldspar maintain relatively stable mechanical properties up to 600℃,whereas significant weakening at mineral interfaces occurs between 400℃ and 500℃,resulting in a greater than 50%reduction in the overall strength and Young's modulus at 600℃.A two-step homogenization approach based on the Mori‒Tanaka framework is proposed,which incorporates a three-phase composite sphere model to characterize the interfacial softening effects.This improved method enhances the prediction accuracy of high-temperature mechanical performance,achieving more than 50%improvement in alignment with experimental data.Despite some deviations above 500℃,the model provides direction for further refinement.This investigation advances the understanding of heterogeneous rock mechanical behavior in high-temperature environments and provides critical theoretical support for geothermal energy development and nuclear waste disposal applications.展开更多
Background:Obesity remains a major global health challenge,closely linked to individuals'health beliefs and lifestyle behaviors.Descriptive and relational research methods were used to ascertain the correlation be...Background:Obesity remains a major global health challenge,closely linked to individuals'health beliefs and lifestyle behaviors.Descriptive and relational research methods were used to ascertain the correlation between health beliefs and healthy lifestyle behaviors in obese individuals based on the Health Belief Model.Methods:The population of the research are obese individuals who are treated in the internal medicine clinic in a state hospital in Diyarbakır and applied to a dietitian.Based on power analysis,the study’s sample consisted of 192 obese people.The health belief model scale in obese individuals(HBMSO),the Healthy Lifestyle Behaviors Scale-II(HLBS-II),and the Personal Information Form were used to gather the data.The data was evaluated using the following methods:mean,standard deviation,linear regression analysis,Mann-Whitney U test,Kruskal-Wallis test,Shapiro Wilk and Kolmogorov Smirnov tests,post-hoc Dunn-Benferronni tests,Pearson and Spearman correlation,and others.Results:It was determined that 26.0%of obese individuals were in the 46–55 age range,63.5%were female,64.6%were married,60.4%had a BMI in the range of 30–34.9 kg/m^(2),and 42.7%partially exercised.All sub-dimensions and HBMSO sub-dimensions had statistically significant correlation with the HLBS-II total score.The linear regression analysis results used to identify the predictors of the HLBS-II total score showed that the increase in the level of education and the HBMSO“Importance of Health”sub-dimension score increased the HLBS-II total score,while not exercising and an increase in the HBMSO“Obstacle Perception”sub-dimension score decreased the HLBS-II total score.Conclusion:Individuals’health attitudes have a major impact on leading a healthy lifestyle,which is consistent with the research results.展开更多
The effects of solid solution on the deformation behavior of binary Mg-xZn(x=0,1,2 wt%)alloys featuring a designated texture that enables extension twinning under tension parallel to the basal pole in most grains,were...The effects of solid solution on the deformation behavior of binary Mg-xZn(x=0,1,2 wt%)alloys featuring a designated texture that enables extension twinning under tension parallel to the basal pole in most grains,were investigated using in-situ neutron diffraction and the EVPSC-TDT model.Neutron diffraction was used to quantitatively track grain-level lattice strains and diffraction intensity changes(related to mechanical twinning)in differently oriented grains of each alloy during cyclic tensile/compressive loadings.These measurements were accurately captured by the model.The stress-strain curves of Mg-1 wt%Zn and Mg-2 wt%Zn alloys show as-expected solid solution strengthening from the addition of Zn compared to pure Mg.The macroscopic yielding and hardening behaviors are explained by alternating slip and twinning modes as calculated by the model.The solid solution's influence on individual deformation modes,including basal〈a〉slip,prismatic〈a〉slip,and extension twinning,was then quantitatively assessed in terms of activity,yielding behavior,and hardening response by combining neutron diffraction results with crystal plasticity predictions.The Mg-1 wt%Zn alloy displays distinct yielding and hardening behavior due to solid solution softening of prismatic〈a〉slip.Additionally,the dependence of extension twinning,in terms of the twinning volume fraction,on Zn content exhibits opposite trends under tensile and compressive loadings.展开更多
The popular constitutive models used in the field of hot forming of magnesium alloys can be divided into phenomenological models,machine learning models,and internal state variables(ISV)models based on physical mechan...The popular constitutive models used in the field of hot forming of magnesium alloys can be divided into phenomenological models,machine learning models,and internal state variables(ISV)models based on physical mechanisms.Currently,there is a lack of comparison and evaluation regarding the suitability of different types of models.In this study,Mg-Gd-Y-Zr alloy is taken as the research object.The hot deformation behavior of the alloy was studied systematically.Subsequently,Arrhenius model with strain compensation,artificial neural network(ANN)model,and ISV model involving dynamic recrystallization(DRX),dislocation density and grain size evolution were established.ANN model demonstrates a higher level of accuracy in fitting the original stress-strain curves compared to both ISV model and modified Arrhenius model,but ANN model is not suitable for predicting the experimental results outside of the initial database.ISV model considers the impact of microstructure evolution history on stress,making it highly effective in reflecting the mechanical responses under complex loading condition.The established ISV model is embedded in the ABAQUS software,which shows good ability in calculating the mechanical response,dimension,and microstructure evolution information of the component during hot forming.展开更多
Objective:To investigate the impact of health education nursing based on the Transtheoretical Model of Behavior Change on self-efficacy in osteoporosis patients with low bone mass.Methods:A total of 91 osteoporosis pa...Objective:To investigate the impact of health education nursing based on the Transtheoretical Model of Behavior Change on self-efficacy in osteoporosis patients with low bone mass.Methods:A total of 91 osteoporosis patients with low bone mass admitted to our hospital from June 2000 to the end of June 2023 were selected and randomly divided into an observation group and a control group using the envelope method,with 46 and 45 cases in each group,respectively.The control group received routine nursing care,while the observation group received health education nursing based on the Transtheoretical Model of Behavior Change.Bone mineral density(lumbar spine L1-L4,femoral neck),disease awareness(Osteoporosis Knowledge Test Questionnaire,OKT-Q),and self-efficacy(Adult Health Self-Management Skills Rating Scale,AHSMSRS)were compared between the two groups.Results:After the intervention,bone mineral density levels,disease awareness levels,and self-efficacy levels significantly increased in both groups,with the observation group showing greater improvements in all indicators compared to the control group(p<0.05).Conclusion:Interventions based on the Transtheoretical Model of Behavior Change effectively enhance patient self-efficacy and bone health by precisely matching behavioral stages,strengthening social support,and regulating neurobehavioral factors.展开更多
To investigate the influence of Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior,isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator a...To investigate the influence of Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior,isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator at temperatures of 380-440℃and strain rates of 0.05-1 s^(−1).The Johnson-Cook model,Hensel-Spittel model,strain-compensated Arrhenius model,and critical fracture strain model were established.Results show that through the evaluation of the models using the correlation coefficient(R)and the average absolute relative error,the strain-compensated Arrhenius model can represent the flow behavior of the alloy more accurately.Shear bands are more pronounced in the as-homogenized specimens,whereas dynamic recrystallization is predominantly observed in as-rolled specimens.Fracture morphology analysis reveals that a mixed fracture mechanism is prevalent in the as-homogenized specimen,whereas a ductile fracture mechanism is predominant in the as-rolled specimen.The processing maps indicate that the unstable region is reduced in the as-rolled specimens compared with that in the as-homogenized specimens.The optimal hot working windows for the as-homogenized and as-rolled specimens are determined as 410-440℃/0.14-1 s^(−1)and 380-400℃/0.05-0.29 s^(−1),respectively.展开更多
This work investigates the effects of deformation mechanisms on the mechanical properties and anisotropy of rolled AZ31B magnesium alloy under uniaxial tension,combining experimental characterization with Visco-Plasti...This work investigates the effects of deformation mechanisms on the mechanical properties and anisotropy of rolled AZ31B magnesium alloy under uniaxial tension,combining experimental characterization with Visco-Plastic Self Consistent(VPSC)modeling.The research focuses particularly on anisotropic mechanical responses along transverse direction(TD)and rolling direction(RD).Experimental measurements and computational simulations consistently demonstrate that prismaticslip activation significantly reduces the strain hardening rate during the initial stage of tensile deformation.By suppressing the activation of specific deformation mechanisms along RD and TD,the tensile mechanical behavior of the magnesium alloy was further investigated.The results show that basalslip has the greatest impact during the initial deformation stage and basalslip activation substantially affects the deformation behavior of AZ31B alloy,causing marked decreases in both yield and tensile strength along RD.Under tensile loading along TD,prismaticslip not only exhibits a synergistic effect on yield strength,but also dominants work hardening during the initial plastic deformation.展开更多
Postoperative infection is a major global health concern,affecting 5%-10%of surgical patients and nearly doubling mortality in severe cases[1].Transplant recipients are particularly vulnerable,with 30%-80%developing i...Postoperative infection is a major global health concern,affecting 5%-10%of surgical patients and nearly doubling mortality in severe cases[1].Transplant recipients are particularly vulnerable,with 30%-80%developing infections within 30 days,often from opportunistic pathogens[2,3].Key risk factors include epidemiological exposure,net immunosuppression,age,transplant type,and surgical history[4].Despite known infection risks,current evidence remains transplantation type-specific and neglects behavioral modulators[5].Different types of transplantation may share similar risk factors[6].To identify common factors affecting postoperative infection,this study collected standardized clinical data-including diet,psychological response,medication use,and biochemical indicators-from liver and kidney transplant patients across six hospitals using a unified standard operating procedure(SOP).展开更多
For studying the carbon thermal reduction rules of titanium in hot metal and providing a theoretical basis for the blast furnace（BF） hearth protection, the distribution behavior of titanium between low-titanium slag...For studying the carbon thermal reduction rules of titanium in hot metal and providing a theoretical basis for the blast furnace（BF） hearth protection, the distribution behavior of titanium between low-titanium slag system of CaO-SiO2-MgO-Al2O3-TiO2 and hot metal was studied using analytical reagents in a temperature range from 1350 °C to 1600 °C. Through high temperature melting, rapid quenching, chemical analysis and thermodynamic model calculating, the results showed that the increase of reaction temperature, which improved the titanium distribution L（Ti） and lowered the system activity coefficient γsys, leads to the rise of equilibrium constant. Combined with Wagner and congregated electron phase models, the data obtained in distribution experiments were used to fit out the Gibbs free energy formula of titanium carbothermic reduction. Finally, the relations between the contents of Si and Ti in hot metal and the titanium load to reach the minimum w（Ti） for the formation of Ti C were given.展开更多
A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distri...A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distribution obtained through approximating the input output function of the SI circuit by conventional wavelet collocation method.In practical applications,the proposed method is a general purpose approach,by which both the small signal effect and the large signal effect are modeled in a unified formulation to ease the process of modeling and simulation.Compared with the published modeling approaches,the proposed nonlinear auto companding method works more efficiently not only in controlling the error distribution but also in reducing the modeling errors.To demonstrate the promising features of the proposed method,several SI circuits are employed as examples to be modeled and simulated.展开更多
A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the paramet...A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the parameters, the back- propagation algorithm is applied to train the proposed neural networks. The proposed model is verified by the typical odd- order-only memory polynomial model in simulation, and the performance is compared with different numbers of taped delay lines（TDLs） and perceptrons of the hidden layer. For validating the TDFFNN model by experiments, a digital test bench is set up to collect input and output data of power amplifiers at a 60 × 10^6 sample/s sampling rate. The 3.75 MHz 16-QAM signal generated in the vector signal generator（VSG） is chosen as the input signal, when measuring the dynamic AM/AM and AM/PM characteristics of power amplifiers. By comparisons and analyses, the presented model provides a good performance in convergence, accuracy and efficiency, which is approved by simulation results and experimental results in the time domain and frequency domain.展开更多
This paper discusses some issues on human reliability model of time dependent human behavior. Some results of the crew reliability experiment on Tsinghua training simulator in China are given, Meanwhile, a case of ca...This paper discusses some issues on human reliability model of time dependent human behavior. Some results of the crew reliability experiment on Tsinghua training simulator in China are given, Meanwhile, a case of calculation for human error probability during anticipated transient without scram (ATWS) based on the data drew from the recent experiment is offered.展开更多
A computer model has been developed to simulate the distribution behaviors of Ni, Co. Sn. Ph,Zn, As, Sb, Bi, An and Ag in copper smelting process. The model assumes that the copper smelting furnaceis in thermodynamic ...A computer model has been developed to simulate the distribution behaviors of Ni, Co. Sn. Ph,Zn, As, Sb, Bi, An and Ag in copper smelting process. The model assumes that the copper smelting furnaceis in thermodynamic equilibrium. As many as 21 elements (Cu. S, Fe. Ni, Co. Sn, As, Sb. Bi, Ph. Zn.An. Ag. O, N, C, H, Ca, Mg, Al, and St) and 73 compounds are considered. This model accounts forphysical entrainment in the melts. The predictions by the present computer model are compared with theknown commercial data from Guixi Smelter in China, Home Smelter in Canada and Naoshima Smelter inJapan. The agreements between the computer predictions and the commercial data are excellent, so that thepresent computer model can be used to monitor and optimize the actual industrial operations of copper smelting. It is applicable to simulation of almost all copper pyrometallurgical processes.展开更多
Dynamic modeling and numerical simulation of hydrate slurry flow behavior are of great importance to offshore hydrate management.For this purpose, a dynamic model of hydrate agglomeration was proposed in this paper.Ba...Dynamic modeling and numerical simulation of hydrate slurry flow behavior are of great importance to offshore hydrate management.For this purpose, a dynamic model of hydrate agglomeration was proposed in this paper.Based on population balance equation, the frame of the dynamic model was established first, which took both hydrate agglomeration and hydrate breakage into consideration.Then, the calculating methods of four key parameters involved in the dynamic model were given according to hydrate agglomeration dynamics.The four key parameters are collision frequency, agglomeration efficiency, breakage frequency and the size distribution of sub particles resulting from particle breakage.After the whole dynamic model was built, it was combined with several traditional solid–liquid flow models and then together solved by the CFD software FLUENT 14.5.Finally, using this method, the influences of flow rate and hydrate volume fraction on hydrate particle size distribution, hydrate volume concentration distribution and pipeline pressure drop were simulated and analyzed.展开更多
The conventional Arrhenius-type model was adopted to identify the deformation characteristic of Ti6 A14 V(TC4) titanium alloy based on the stress-strain curves of isothermal compression test. A new flow stress model b...The conventional Arrhenius-type model was adopted to identify the deformation characteristic of Ti6 A14 V(TC4) titanium alloy based on the stress-strain curves of isothermal compression test. A new flow stress model based on Arrhenius equation was proposed for TC4,which is composed of peak flow stress(PFS) prediction and strain compensation. The predicted PFS is set as a reference to derive the flow stress model at any strain ranging from approximately 0 to 0.7. The predictability and efficiency among the proposed model, conventional model,and an existing physical-based model of TC4 were comparatively evaluated. It is found that the newly proposed model can simultaneously track the hardening and softening behaviors of TC4 through a single expression while the other existing models are only valid in the softening region.Besides, the wider application range and acceptable accuracy of the new model have been achieved by fewer material constants with much-simplified modeling procedure than the other models.展开更多
基金supported by the 2025 Jiangsu Province Graduate Student Practice Innovation Program(No.SJCX25_1696)the 2024 Changzhou University Educational Research Project(No.GJY2024009).
文摘Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.Current research on the associations between 24-hour movement behaviors(including physical activity,sedentary behavior,and sleep)and depression has largely been confined to examining the effects of single behaviors,overlooking the intrinsic compositional nature and interrelationships among these behaviors.Therefore,it is necessary to investigate the integrated effects of 24-hour movement behaviors on depression in older adults with multimorbidity from a holistic,compositional perspective.Methods:From November 2024 to April 2025,a total of 226 older adult patients with multimorbidity were recruited from a tertiary hospital in Changzhou City.Data were collected using a general information questionnaire,the International Physical Activity Questionnaire–Short Form(IPAQ-SF),the Pittsburgh Sleep Quality Index(PSQI),and the Patient Health Questionnaire-9(PHQ-9).Compositional data analysis and isotemporal substitution models were employed for statistical analysis.Results:The mean daily durations of Light-Intensity Physical Activity(LPA),Moderate-to-Vigorous Physical Activity(MVPA),Sedentary Behavior(SB),and Sleep(SLP)in older adults with multimorbidity were 402.48 min,12.04 min,511.52 min,and 458.68 min,respectively.The prevalence of depressive symptoms was 37.6%.Compositional data analysis revealed that SB was positively associated with depression(βSB=1.005,P=0.006),while SLP was negatively associated with depression(βSLP=−1.736,P<0.001).No statistically significant associations were found between MVPA or LPA and depression(P>0.05).In the 10-minute isotemporal substitution model,replacing SB with any other behavioral component was associated with a decrease in depression scores.Conversely,substituting SLP with either LPA or SB resulted in an increase in depression scores,while substituting SLP with MVPA led to a decrease in depression scores.The dose-response analysis revealed that,among the isotemporal substitution effects,replacing SB with SLP and replacing SLP with MVPA were the substitution pathways associated with the most rapid decline in depression scores,representing the greatest beneficial health effects.Conclusion:The prevalence of depression is notably high among older adults with multimorbidity.Reducing daily sedentary behavior(SB),maintaining adequate sleep(SLP),and increasing moderate-to-vigorous physical activity(MVPA)can improve depressive symptoms and enhance overall health in this population.
基金Project(42202318)supported by the National Natural Science Foundation of ChinaProject(252300421199)supported by the Natural Science Foundation of Henan Province,ChinaProject(2024JJ6219)supported by the Hunan Provincial Natural Science Foundation of China。
文摘The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects.
文摘One of the main objectives of artificial intelligence lies in the simulation of the behavior of living organisms;emotions are a fundamental part of life, and they cannot be left aside when simulating behavior. In this research, software is developed that simulates the behavior of birds with different characteristics. The latter interacts by considering different stimuli from the environment (external), and the internal state of the subject (objectives). To achieve this, a model of birds in the role of prey and predators is developed that focuses on the study of the interaction between these organisms that exhibit specific behaviors in their environment. This project is a seminal work that aims to represent the emotions of birds, and the latter caused by stimuli from a dynamic environment.
基金supported by the National Natural Science Foun-dation of China(Grant No.52478335)the 2023 Annual Science and Technology Project of Jiangsu Province Construction System(Grant No.90)the Science and Technology Research and Develop-ment Topic of CSCEC 7th Division(Grant No.CSCEC7b-2024-Z-4).
文摘This work aims to investigate the thermo-poromechanical behavior of saturated silt clay(SC)under varying temperatures through experiments and constitutive modeling.A series of undrained triaxial compression tests was conducted on saturated SC with temperature ranges from 25℃to 60℃.The effects of temperature on the main poromechanical properties of saturated SC,such as stress-strain relations,pore pressure evolution,and strength parameters,were thoroughly examined.Based on the experimental results,a subtly thermodynamically consistent thermo-poromechanical model was established using the concept of effective plastic stress within the poromechanical framework.Plastic deformation was described with a specific yield criterion and non-associated plastic potential that both depend on the effective plastic stress and a simple hardening variable.Finally,this model was implemented by a semi-implicit return mapping algorithm(SRMA)and validated through the comparison of model predictions and experimental data.The proposed model accurately reproduces the main thermo-poromechanical characteristics observed in saturated SC.
基金support from the National Key Research and Development Program of China(Grant No.2023YFB4005500)the National Natural Science Foundation of China(Grant Nos.42472312 and 52090081).
文摘In this study,nanoindentation techniques,macroscopic mechanical testing,and the Mori-Tanaka theoretical model are integrated to analyze the thermal‒mechanical behavior of granite systematically.The experimental results demonstrate that quartz and feldspar maintain relatively stable mechanical properties up to 600℃,whereas significant weakening at mineral interfaces occurs between 400℃ and 500℃,resulting in a greater than 50%reduction in the overall strength and Young's modulus at 600℃.A two-step homogenization approach based on the Mori‒Tanaka framework is proposed,which incorporates a three-phase composite sphere model to characterize the interfacial softening effects.This improved method enhances the prediction accuracy of high-temperature mechanical performance,achieving more than 50%improvement in alignment with experimental data.Despite some deviations above 500℃,the model provides direction for further refinement.This investigation advances the understanding of heterogeneous rock mechanical behavior in high-temperature environments and provides critical theoretical support for geothermal energy development and nuclear waste disposal applications.
文摘Background:Obesity remains a major global health challenge,closely linked to individuals'health beliefs and lifestyle behaviors.Descriptive and relational research methods were used to ascertain the correlation between health beliefs and healthy lifestyle behaviors in obese individuals based on the Health Belief Model.Methods:The population of the research are obese individuals who are treated in the internal medicine clinic in a state hospital in Diyarbakır and applied to a dietitian.Based on power analysis,the study’s sample consisted of 192 obese people.The health belief model scale in obese individuals(HBMSO),the Healthy Lifestyle Behaviors Scale-II(HLBS-II),and the Personal Information Form were used to gather the data.The data was evaluated using the following methods:mean,standard deviation,linear regression analysis,Mann-Whitney U test,Kruskal-Wallis test,Shapiro Wilk and Kolmogorov Smirnov tests,post-hoc Dunn-Benferronni tests,Pearson and Spearman correlation,and others.Results:It was determined that 26.0%of obese individuals were in the 46–55 age range,63.5%were female,64.6%were married,60.4%had a BMI in the range of 30–34.9 kg/m^(2),and 42.7%partially exercised.All sub-dimensions and HBMSO sub-dimensions had statistically significant correlation with the HLBS-II total score.The linear regression analysis results used to identify the predictors of the HLBS-II total score showed that the increase in the level of education and the HBMSO“Importance of Health”sub-dimension score increased the HLBS-II total score,while not exercising and an increase in the HBMSO“Obstacle Perception”sub-dimension score decreased the HLBS-II total score.Conclusion:Individuals’health attitudes have a major impact on leading a healthy lifestyle,which is consistent with the research results.
基金supported by the National Research Foundation grant funded by the Korean government(No,2023R1A2C2007190,RS-2024-00398068)partially funded by the Natural Science Foundation of Shandong Province,China(No.ZR2022QE206).
文摘The effects of solid solution on the deformation behavior of binary Mg-xZn(x=0,1,2 wt%)alloys featuring a designated texture that enables extension twinning under tension parallel to the basal pole in most grains,were investigated using in-situ neutron diffraction and the EVPSC-TDT model.Neutron diffraction was used to quantitatively track grain-level lattice strains and diffraction intensity changes(related to mechanical twinning)in differently oriented grains of each alloy during cyclic tensile/compressive loadings.These measurements were accurately captured by the model.The stress-strain curves of Mg-1 wt%Zn and Mg-2 wt%Zn alloys show as-expected solid solution strengthening from the addition of Zn compared to pure Mg.The macroscopic yielding and hardening behaviors are explained by alternating slip and twinning modes as calculated by the model.The solid solution's influence on individual deformation modes,including basal〈a〉slip,prismatic〈a〉slip,and extension twinning,was then quantitatively assessed in terms of activity,yielding behavior,and hardening response by combining neutron diffraction results with crystal plasticity predictions.The Mg-1 wt%Zn alloy displays distinct yielding and hardening behavior due to solid solution softening of prismatic〈a〉slip.Additionally,the dependence of extension twinning,in terms of the twinning volume fraction,on Zn content exhibits opposite trends under tensile and compressive loadings.
基金supported by the fund of the National Natural Science Foundation of China(52275322,51875127)。
文摘The popular constitutive models used in the field of hot forming of magnesium alloys can be divided into phenomenological models,machine learning models,and internal state variables(ISV)models based on physical mechanisms.Currently,there is a lack of comparison and evaluation regarding the suitability of different types of models.In this study,Mg-Gd-Y-Zr alloy is taken as the research object.The hot deformation behavior of the alloy was studied systematically.Subsequently,Arrhenius model with strain compensation,artificial neural network(ANN)model,and ISV model involving dynamic recrystallization(DRX),dislocation density and grain size evolution were established.ANN model demonstrates a higher level of accuracy in fitting the original stress-strain curves compared to both ISV model and modified Arrhenius model,but ANN model is not suitable for predicting the experimental results outside of the initial database.ISV model considers the impact of microstructure evolution history on stress,making it highly effective in reflecting the mechanical responses under complex loading condition.The established ISV model is embedded in the ABAQUS software,which shows good ability in calculating the mechanical response,dimension,and microstructure evolution information of the component during hot forming.
基金National Key Research and Development Program of China(Project No.:2020YFC2004900)。
文摘Objective:To investigate the impact of health education nursing based on the Transtheoretical Model of Behavior Change on self-efficacy in osteoporosis patients with low bone mass.Methods:A total of 91 osteoporosis patients with low bone mass admitted to our hospital from June 2000 to the end of June 2023 were selected and randomly divided into an observation group and a control group using the envelope method,with 46 and 45 cases in each group,respectively.The control group received routine nursing care,while the observation group received health education nursing based on the Transtheoretical Model of Behavior Change.Bone mineral density(lumbar spine L1-L4,femoral neck),disease awareness(Osteoporosis Knowledge Test Questionnaire,OKT-Q),and self-efficacy(Adult Health Self-Management Skills Rating Scale,AHSMSRS)were compared between the two groups.Results:After the intervention,bone mineral density levels,disease awareness levels,and self-efficacy levels significantly increased in both groups,with the observation group showing greater improvements in all indicators compared to the control group(p<0.05).Conclusion:Interventions based on the Transtheoretical Model of Behavior Change effectively enhance patient self-efficacy and bone health by precisely matching behavioral stages,strengthening social support,and regulating neurobehavioral factors.
文摘To investigate the influence of Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior,isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator at temperatures of 380-440℃and strain rates of 0.05-1 s^(−1).The Johnson-Cook model,Hensel-Spittel model,strain-compensated Arrhenius model,and critical fracture strain model were established.Results show that through the evaluation of the models using the correlation coefficient(R)and the average absolute relative error,the strain-compensated Arrhenius model can represent the flow behavior of the alloy more accurately.Shear bands are more pronounced in the as-homogenized specimens,whereas dynamic recrystallization is predominantly observed in as-rolled specimens.Fracture morphology analysis reveals that a mixed fracture mechanism is prevalent in the as-homogenized specimen,whereas a ductile fracture mechanism is predominant in the as-rolled specimen.The processing maps indicate that the unstable region is reduced in the as-rolled specimens compared with that in the as-homogenized specimens.The optimal hot working windows for the as-homogenized and as-rolled specimens are determined as 410-440℃/0.14-1 s^(−1)and 380-400℃/0.05-0.29 s^(−1),respectively.
基金supported by the National Nature Science Foundation of China(52275356).
文摘This work investigates the effects of deformation mechanisms on the mechanical properties and anisotropy of rolled AZ31B magnesium alloy under uniaxial tension,combining experimental characterization with Visco-Plastic Self Consistent(VPSC)modeling.The research focuses particularly on anisotropic mechanical responses along transverse direction(TD)and rolling direction(RD).Experimental measurements and computational simulations consistently demonstrate that prismaticslip activation significantly reduces the strain hardening rate during the initial stage of tensile deformation.By suppressing the activation of specific deformation mechanisms along RD and TD,the tensile mechanical behavior of the magnesium alloy was further investigated.The results show that basalslip has the greatest impact during the initial deformation stage and basalslip activation substantially affects the deformation behavior of AZ31B alloy,causing marked decreases in both yield and tensile strength along RD.Under tensile loading along TD,prismaticslip not only exhibits a synergistic effect on yield strength,but also dominants work hardening during the initial plastic deformation.
基金the MOST Key Research and Development Program of China(grant number 2022YFC2304703)the Natural Science Foundation of China(grant number 32422004)+5 种基金The Medicine and Engineering Interdisciplinary Research Fund of Shanghai Jiao Tong University(grant number 24X010301328)the Natural Science Foundation of China(grant number 32270202)the Computational Biology Program of Science and Technology Commission of Shanghai Municipality(STCSM)(grant number 25JS2810200)the MOST Key Research and Development Program of China(grant number 2020YFA0907200)Program of Shanghai Academic Research Leader(grant number 23XD1422300)Innovative research team of high-level local universities in Shanghai.All funding sources are attributed to N.N.L.
文摘Postoperative infection is a major global health concern,affecting 5%-10%of surgical patients and nearly doubling mortality in severe cases[1].Transplant recipients are particularly vulnerable,with 30%-80%developing infections within 30 days,often from opportunistic pathogens[2,3].Key risk factors include epidemiological exposure,net immunosuppression,age,transplant type,and surgical history[4].Despite known infection risks,current evidence remains transplantation type-specific and neglects behavioral modulators[5].Different types of transplantation may share similar risk factors[6].To identify common factors affecting postoperative infection,this study collected standardized clinical data-including diet,psychological response,medication use,and biochemical indicators-from liver and kidney transplant patients across six hospitals using a unified standard operating procedure(SOP).
基金Project(2012CB720401)supported by the National Basic Research Program of ChinaProject(2011BAC01B02)supported by the National Key Technology R&D Program of China
文摘For studying the carbon thermal reduction rules of titanium in hot metal and providing a theoretical basis for the blast furnace（BF） hearth protection, the distribution behavior of titanium between low-titanium slag system of CaO-SiO2-MgO-Al2O3-TiO2 and hot metal was studied using analytical reagents in a temperature range from 1350 °C to 1600 °C. Through high temperature melting, rapid quenching, chemical analysis and thermodynamic model calculating, the results showed that the increase of reaction temperature, which improved the titanium distribution L（Ti） and lowered the system activity coefficient γsys, leads to the rise of equilibrium constant. Combined with Wagner and congregated electron phase models, the data obtained in distribution experiments were used to fit out the Gibbs free energy formula of titanium carbothermic reduction. Finally, the relations between the contents of Si and Ti in hot metal and the titanium load to reach the minimum w（Ti） for the formation of Ti C were given.
文摘A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distribution obtained through approximating the input output function of the SI circuit by conventional wavelet collocation method.In practical applications,the proposed method is a general purpose approach,by which both the small signal effect and the large signal effect are modeled in a unified formulation to ease the process of modeling and simulation.Compared with the published modeling approaches,the proposed nonlinear auto companding method works more efficiently not only in controlling the error distribution but also in reducing the modeling errors.To demonstrate the promising features of the proposed method,several SI circuits are employed as examples to be modeled and simulated.
基金The National Natural Science Foundation of China(No.60621002)the National High Technology Research and Development Pro-gram of China(863 Program)(No.2007AA01Z2B4).
文摘A novel behavioral model using three-layer time-delay feed-forward neural networks （TDFFNN）is adopted to model radio frequency （RF）power amplifiers exhibiting memory nonlinearities. In order to extract the parameters, the back- propagation algorithm is applied to train the proposed neural networks. The proposed model is verified by the typical odd- order-only memory polynomial model in simulation, and the performance is compared with different numbers of taped delay lines（TDLs） and perceptrons of the hidden layer. For validating the TDFFNN model by experiments, a digital test bench is set up to collect input and output data of power amplifiers at a 60 × 10^6 sample/s sampling rate. The 3.75 MHz 16-QAM signal generated in the vector signal generator（VSG） is chosen as the input signal, when measuring the dynamic AM/AM and AM/PM characteristics of power amplifiers. By comparisons and analyses, the presented model provides a good performance in convergence, accuracy and efficiency, which is approved by simulation results and experimental results in the time domain and frequency domain.
文摘This paper discusses some issues on human reliability model of time dependent human behavior. Some results of the crew reliability experiment on Tsinghua training simulator in China are given, Meanwhile, a case of calculation for human error probability during anticipated transient without scram (ATWS) based on the data drew from the recent experiment is offered.
文摘A computer model has been developed to simulate the distribution behaviors of Ni, Co. Sn. Ph,Zn, As, Sb, Bi, An and Ag in copper smelting process. The model assumes that the copper smelting furnaceis in thermodynamic equilibrium. As many as 21 elements (Cu. S, Fe. Ni, Co. Sn, As, Sb. Bi, Ph. Zn.An. Ag. O, N, C, H, Ca, Mg, Al, and St) and 73 compounds are considered. This model accounts forphysical entrainment in the melts. The predictions by the present computer model are compared with theknown commercial data from Guixi Smelter in China, Home Smelter in Canada and Naoshima Smelter inJapan. The agreements between the computer predictions and the commercial data are excellent, so that thepresent computer model can be used to monitor and optimize the actual industrial operations of copper smelting. It is applicable to simulation of almost all copper pyrometallurgical processes.
基金Supported by Shandong Provincial Natural Science Foundation,China(ZR2017MEE057)the Fundamental Research Funds for the Central Universities(14CX02207A,17CX05006,17CX06017)the Graduate Innovation Project of China University of Petroleum(East China)(YCX2017062)
文摘Dynamic modeling and numerical simulation of hydrate slurry flow behavior are of great importance to offshore hydrate management.For this purpose, a dynamic model of hydrate agglomeration was proposed in this paper.Based on population balance equation, the frame of the dynamic model was established first, which took both hydrate agglomeration and hydrate breakage into consideration.Then, the calculating methods of four key parameters involved in the dynamic model were given according to hydrate agglomeration dynamics.The four key parameters are collision frequency, agglomeration efficiency, breakage frequency and the size distribution of sub particles resulting from particle breakage.After the whole dynamic model was built, it was combined with several traditional solid–liquid flow models and then together solved by the CFD software FLUENT 14.5.Finally, using this method, the influences of flow rate and hydrate volume fraction on hydrate particle size distribution, hydrate volume concentration distribution and pipeline pressure drop were simulated and analyzed.
基金financially supported by the National Natural Science Foundation of China (No. 51475295)
文摘The conventional Arrhenius-type model was adopted to identify the deformation characteristic of Ti6 A14 V(TC4) titanium alloy based on the stress-strain curves of isothermal compression test. A new flow stress model based on Arrhenius equation was proposed for TC4,which is composed of peak flow stress(PFS) prediction and strain compensation. The predicted PFS is set as a reference to derive the flow stress model at any strain ranging from approximately 0 to 0.7. The predictability and efficiency among the proposed model, conventional model,and an existing physical-based model of TC4 were comparatively evaluated. It is found that the newly proposed model can simultaneously track the hardening and softening behaviors of TC4 through a single expression while the other existing models are only valid in the softening region.Besides, the wider application range and acceptable accuracy of the new model have been achieved by fewer material constants with much-simplified modeling procedure than the other models.
