This study aimed to investigate the link between the exposure to intimate partner violence(IPV),core self-evaluations(CSE),and psychological adaptation of Chinese adolescents,through analysis of the results from the S...This study aimed to investigate the link between the exposure to intimate partner violence(IPV),core self-evaluations(CSE),and psychological adaptation of Chinese adolescents,through analysis of the results from the Survey of Children’s Exposure to Domestic Violence Scale,Core Self-Evaluations Scale,and Strengths and Difficulties Questionnaire,involving a total of 597 Chinese middle school students.It is indicated that the exposure to IPV is positively correlated with lower levels of psychological adaptation and CSE,and CSE is positively correlated with higher levels of psychological adaptation.Mediation analysis revealed that CSE partially mediated the association between the exposure to IPV and psychological adaptation.These results suggest that educators and parents should help adolescents tackle their emotional and behavioral problems by reducing the risk of IPV exposure and increasing their CSE.展开更多
This study aims to examine the relationship between authentic leadership and employee proactive behavior. Based on self-determination theory, we argue that such a relationship is sequentially mediated by psychological...This study aims to examine the relationship between authentic leadership and employee proactive behavior. Based on self-determination theory, we argue that such a relationship is sequentially mediated by psychological empowerment and core self-evaluations. In addition, political skill plays a moderating role in the third stage. These hypotheses are validated by a sample of 65 leaders and 275 subordinates from two private enterprises in China's Mainland. Results show that authentic leadership Clime I） influences employees＇ proactive behavior Clime 3） through the psychological empowerment （Time I） and core self-evaluations of employees （Time 2）, and the relationship between core self-evaluations and proactive behavior is positively moderated by employees＇ political skill. In addition, bootstrapping results also verify the moderating role played by employees＇ political skill in the indirect relationship between authentic leadership and proactive behavior through core self-evaluations. Theoretical and managerial implications are further discussed in the light of these findings.展开更多
Background:Social anxiety is prevalent among adolescents and severely impacts their mental health and social functioning.This study aims to explore the underlying mechanisms and subgroup differences in adolescent soci...Background:Social anxiety is prevalent among adolescents and severely impacts their mental health and social functioning.This study aims to explore the underlying mechanisms and subgroup differences in adolescent social anxiety to provide a theoretical basis for targeted interventions.Methods:3025 Chinese adolescents(Meanage=13.91±1.60 years;47%male)completed self-report measures of physical activity,core self-evaluation,and social anxiety.Variable-centered analyses employed PROCESS Model 4 with 5000 bootstrap samples;covariates were gender,grade,and place of residence.Person-centered analyses used latent profile analysis in Mplus 8.3 to identify subgroups based on social anxiety item profiles.Results:Variable-centered analyses showed that physical activity had a significant negative association with social anxiety(β=−0.224,p<0.001)and a significant positive association with core self-evaluation(β=0.471,p<0.001);core self-evaluation partially mediated this relationship,accounting for 30%of the total effect.Person-centered analyses revealed an optimal two-profile solution:a low social anxiety profile(89.6%)and a high social anxiety profile(10.4%).The high social anxiety profile reported significantly lower physical activity and lower core self-evaluation than the low social anxiety profile.Conclusions:This study integrates variable-centered and person-centered evidence,identifies physical activity and core self-evaluation as key modifiable factors in reducing social anxiety,providing a theoretical basis for targeted and differentiated interventions.展开更多
This study aimed to explore how core self-evaluations and gender influence interpersonal adjustment and depression risk.Participants were 1748 college students(female=59.73%,male=40.27%,mean age=18.71 years,SD=0.78 yea...This study aimed to explore how core self-evaluations and gender influence interpersonal adjustment and depression risk.Participants were 1748 college students(female=59.73%,male=40.27%,mean age=18.71 years,SD=0.78 years).The students completed the Interpersonal Adjustment Scale for College Students,Center for Epidemiological Studies Depression Scale,and Core Self-evaluation Scale.The results of Linear regression and mediated moderated effects modeling revealed that college students with higher interpersonal adjustment and core self-evaluation scores were at lower risk for depression.Core self-evaluation mediated the relationship between interpersonal adjustment and depression in college students for lower risk for depression.Gender moderated the relationship between interpersonal adjustment and core self-evaluation in college students for higher risk for depression in female students.From thesefindings,we conclude that interpersonal adjustment and core self-evaluation are significant for screening depression risk college students.Moreover,female students may benefit from targeted interventions aimed at their interpersonal adjustment for reducing their risk of depression.展开更多
The Martian core mainly contains iron,nickel and some light elements.However,controversies remain about the structure and chemical composition of the Martian core due to a lack of samples and marsquake data.Recently,t...The Martian core mainly contains iron,nickel and some light elements.However,controversies remain about the structure and chemical composition of the Martian core due to a lack of samples and marsquake data.Recently,the InSight lander collected long-term marsquake data,which improved the Martian interior structure model.B ased on the preliminary analysis of marsquake data,Mars has a molten liquid core with a radius of around 1700 km.As the Martian core has a smaller density and lower temperature than pure iron at corresponding pressure and temperature conditions,some light elements are introduced to reduce the density and liquidus temperature.With various methods for seismic analysis,in-situ high-pressure and high-temperature experiments,and first-principal calculations,the Martian core composition and evolution models have been updated in the past few years.Here,we review those studies on the light elements in the Martian core from four aspects including(1)high-temperature and high-pressure experiments,(2)marsquake data,(3)mineral physics model with molecular dynamics simulations and(4)cosmochemistry investigation.We discussed the effect of different light elements on the Martian core s density,sound velocity and liquidus temperature.Moreover,the review examines the varieties,abundances and forms of light elements in the Martian core.展开更多
Low reactivity and appropriate wettability between molten superalloys and ceramic materials are crucial for the production of high-quality superalloy castings.The sessile-drop experiment was employed to systematically...Low reactivity and appropriate wettability between molten superalloys and ceramic materials are crucial for the production of high-quality superalloy castings.The sessile-drop experiment was employed to systematically investigate the interfacial reaction and wettability between the 4777DS1 superalloy and SiO_(2)-based ceramic core at various temperatures(1,480℃,1,500℃,1,520℃,and 1,550℃).The wetting behavior and interfacial reaction products at different temperatures were analyzed by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and X-ray diffraction(XRD).The interfacial reaction process and products were discussed,and the thermodynamic behavior and interfacial reaction mechanisms were elucidated.The results demonstrate that the wetting behavior and interfacial reaction between the 4777DS1 alloy and the ceramic core are significantly influenced by temperature.The wettability angle exhibits a trend of initial decrease followed by an increase with rising temperature,reaching a maximum of 139°at 1,480℃,indicating poorer wettability of the 4777DS1 superalloy with the ceramic core and better casting properties at this specific temperature.The most intense interfacial reaction occurs at 1,520℃,resulting in the formation of the main interfacial reaction products such as Al_(2)O_(3),SiO_(2),and HfO_(2).Additionally,some crystal-like products rich in Si and Hf distribute on the reaction layer.展开更多
Internet gaming disorder(IGD)among junior high school students is an increasingly prominent mental health concern.It is important to look for influences behind internet gaming disorder tendency(IGDT)in the junior high...Internet gaming disorder(IGD)among junior high school students is an increasingly prominent mental health concern.It is important to look for influences behind internet gaming disorder tendency(IGDT)in the junior high school student population.The present study aimed to reveal the explanatory mechanisms underlying the association between parental psychological control(PPC)and internet gaming disorder tendency among junior high school students by testing the mediating role of core self-evaluation(CSE)and the moderating role of intentional self-regulation(ISR).Participants in present study were 735 Chinese junior high school students who completed offline self-report questionnaires on parental psychological control,core self-evaluation,intentional self-regulation,and Internet gaming disorder tendency.Analyses were conducted via mediation and moderated mediation.The results showed that:(1)Parental psychological control was positively related to junior high school students’Internet gaming disorder tendency.Core self-evaluation,and intentional self-regulation were negatively related to junior high school students’Internet gaming disorder tendency,respectively.(2)Core self-evaluation partially mediated the relationship between parental psychological control and junior high school students’Internet gaming disorder tendency.(3)Intentional self-regulation moderated the association between parental psychological control and Internet gaming disorder tendency,as well as the relationships between parental psychological control and core self-evaluation and core self-evaluation and Internet gaming disorder tendency in the mediated model.Based on these findings,we believe that there is a need to weaken parental psychological control,strengthen junior high school students’core self-evaluation and intentional self-regulation,and to recognize the important role of parents as well as their children’s personal positive traits in the healthy development of junior high school students.展开更多
The present study discusses the relationship among Chinese adolescents’parental involvement,core self-evaluation,and school adaptation.The Parental Involvement Behavior Questionnaire,Core Self-Evaluations Scale(CSES)...The present study discusses the relationship among Chinese adolescents’parental involvement,core self-evaluation,and school adaptation.The Parental Involvement Behavior Questionnaire,Core Self-Evaluations Scale(CSES),and the School Adaptation Inventory were used to survey 1258 Chinese middle school students.The results showed that adolescents’school adaptation was significantly positively correlated with parental involvement and core self-evaluation.Furthermore,parental involvement and core self-evaluation were positively correlated.Mediation analysis found that core self-evaluation had partially mediated the relationship between adolescents’parental involvement and school adaption.Parental involvement could directly affect adolescents’school adaptation and indirectly affect school adaptation through the mediating effect of core self-evaluation.The present study results suggested that parents and educators could improve adolescents’school adaptation by increasing parental involvement and enhancing the adolescents’core self-evaluation.展开更多
Deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures,thus the seepage characteristics are significant for enhancing oil production.This study conducted triaxial compression an...Deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures,thus the seepage characteristics are significant for enhancing oil production.This study conducted triaxial compression and permeability tests to investigate the mechanical and seepage properties of tight sandstone.A digital core of tight sandstone was built using Computed Tomography(CT)scanning,which was divided into matrix and pore phases by a pore equivalent diameter threshold.A fluid-solid coupling model was established to investigate the seepage characteristics at micro-scale.The results showed that increasing the confining pressure decreased porosity,permeability,and flow velocity,with the pore phase becoming the dominant seepage channel.Cracks and large pores closed first under increasing pressure,resulted in a steep drop in permeability.However,permeability slightly decreased under high confining pressure,which followed a first-order exponential function.Flow velocity increased with seepage pressure.And the damage mainly occurred in stress-concentration regions under low seepage pressure.Seepage behavior followed linear Darcy flow,the damage emerged at seepage entrances under high pressure,which decreased rock elastic modulus and significantly increased permeability.展开更多
This study aimed to explore university students’perceptions on the possession of core competencies for the 21st century.A crosssectional survey research using a self-report questionnaire involving 40 Likert-type item...This study aimed to explore university students’perceptions on the possession of core competencies for the 21st century.A crosssectional survey research using a self-report questionnaire involving 40 Likert-type items was used to collect data from 5,042 university students in China who voluntarily participated.Analysis with Rasch rating scale model found the data fitted the Rasch model well.The results showed that Chinese university students considered themselves as having acquired most of the competencies to some extent,especially in Character and Civic Literacy and Interpersonal Communication,but less so in Global and International Perspective and Creativity and Problem Solving.展开更多
The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large de...The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large deformation during the LCR process and to minimize the thickness of the slab in bending segments,the maximum theoretical reduction amount and the corresponding reduction scheme for the LCR process must be determined.With SPA-H weathering steel as a specific research steel grade,the distributions of tem-perature and deformation fields of a slab with the LCR process were analyzed using a three-dimensional thermal-mechanical finite ele-ment model.High-temperature tensile tests were designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperatures,and a prediction model of the critical strain for two typical cracks,combining the effects of strain rate and temperature,was proposed by incorporating the Zener-Hollomon parameter.The crack risks with different LCR schemes were calculated using the crack risk prediction model,and the maximum theoretical reduction amount for the SPA-H slab with a transverse section of 145 mm×1600 mm was 41.8 mm,with corresponding reduction amounts for Segment 0 to Segment 4 of 15.8,7.3,6.5,6.4,and 5.8 mm,respectively.展开更多
Research on the mechanical–electrical properties is crucial for designing and preparing high-temperature superconducting(HTS)cables.Various winding core structures can influence the mechanical–electrical behavior of...Research on the mechanical–electrical properties is crucial for designing and preparing high-temperature superconducting(HTS)cables.Various winding core structures can influence the mechanical–electrical behavior of cables,but the impact of alterations in the winding core structure on the mechanical–electrical behavior of superconducting cables remains unclear.This paper presents a 3D finite element model to predict the performance of three cables with different core structures when subjected to transverse compression and axial tension.The three cables analyzed are CORC(conductor-on-round-core),CORT(conductor-on-round-tube),and HFRC(conductor-on-spiral-tube).A parametric analysis is carried out by varying the core diameter and inner-to-outer diameter ratio.Results indicate that the CORT cable demonstrates better performance in transverse compression compared to the CORC cable,aligning with experimental data.Among the three cables,the HFRC cables exhibit the weakest resistance to transverse deformation.However,the HFRC cable demonstrates superior tensile deformation resistance compared to the CORT cable,provided that the transverse compression properties are maintained.Finite element results also show that the optimum inner-to-outer diameter ratios for achieving the best transverse compression performance are approximately 0.8 for CORT cables and 0.6 for HFRC cables.Meanwhile,the study explores the effect of structural changes in HTS cable winding cores on their electromagnetic properties.It recommends utilizing small tape gaps,lower frequencies,and spiral core construction to minimize eddy losses.The findings presented in this paper offer valuable insights for the commercialization and practical manufacturing of HTS cables.展开更多
For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this work.The plate comprises a lattic...For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this work.The plate comprises a lattice core located in the middle and several homogeneous orthotropic layers that are symmetrical relative to it.For this purpose,the partial differential equations of motion have been derived based on the first-order shear deformation theory,employing Hamilton’s principle and Von Kármán’s nonlinear displacement-strain relations.Then,the nonlinear partial differential equations of the plate are converted into a time-dependent nonlinear ordinary differential equation(Duffing equation)by applying the Galerkin method.From the solution of this equation,the natural frequencies are extracted.Then,to calculate the non-linear frequencies of the plate,the non-linear equation of the plate has been solved analytically using the method of multiple scales.Finally,the effect of some critical parameters of the system,such as the thickness,height,and different angles of the stiffeners on the linear and nonlinear frequencies,has been analyzed in detail.To confirmthe solution method,the results of this research have been compared with the reported results in the literature and finite elements in ABAQUS,and a perfect match is observed.The results reveal that the geometry and configuration of core ribs strongly affect the natural frequencies of the plate.展开更多
Coral reef limestone(CRL)constitutes a distinctive marine carbonate formation with complex mechanical properties.This study investigates the multiscale damage and fracture mechanisms of CRL through integrated experime...Coral reef limestone(CRL)constitutes a distinctive marine carbonate formation with complex mechanical properties.This study investigates the multiscale damage and fracture mechanisms of CRL through integrated experimental testing,digital core technology,and theoretical modelling.Two CRL types with contrasting mesostructures were characterized across three scales.Macroscopically,CRL-I and CRL-II exhibited mean compressive strengths of 8.46 and 5.17 MPa,respectively.Mesoscopically,CRL-I featured small-scale highly interconnected pores,whilst CRL-II developed larger stratified pores with diminished connectivity.Microscopically,both CRL matrices demonstrated remarkable similarity in mineral composition and mechanical properties.A novel voxel average-based digital core scaling methodology was developed to facilitate numerical simulation of cross-scale damage processes,revealing network-progressive failure in CRL-I versus directional-brittle failure in CRL-II.Furthermore,a damage statistical constitutive model based on digital core technology and mesoscopic homogenisation theory established quantitative relationships between microelement strength distribution and macroscopic mechanical behavior.These findings illuminate the fundamental mechanisms through which mesoscopic structure governs the macroscopic mechanical properties of CRL.展开更多
Core power is a key parameter of nuclear reactor.Traditionally,the proportional-integralderivative(PID)controllers are used to control the core power.Fractional-order PID(FOPID)controller represents the cutting edge i...Core power is a key parameter of nuclear reactor.Traditionally,the proportional-integralderivative(PID)controllers are used to control the core power.Fractional-order PID(FOPID)controller represents the cutting edge in core power control research.In comparing with the integer-order models,fractional-order models describe the variation of core power more accurately,thus provide a comprehensive and realistic depiction for the power and state changes of reactor core.However,current fractional-order controllers cannot adjust their parameters dynamically to response the environmental changes or demands.In this paper,we aim at the stable control and dynamic responsiveness of core power.Based on the strong selflearning ability of artificial neural network(ANN),we propose a composite controller combining the ANN and FOPID controller.The FOPID controller is firstly designed and a back propagation neural network(BPNN)is then utilized to optimize the parameters of FOPID.It is shown by simulation that the composite controller enables the real-time parameter tuning via ANN and retains the advantage of FOPID controller.展开更多
Lead chalcohalides(PbYX,X=Cl,Br,I;Y=S,Se)is an extension of the classic Pb chalcogenides(PbY).Constructing the heterogeneous integration with PbYX and PbY material systems makes it possible to achieve significantly im...Lead chalcohalides(PbYX,X=Cl,Br,I;Y=S,Se)is an extension of the classic Pb chalcogenides(PbY).Constructing the heterogeneous integration with PbYX and PbY material systems makes it possible to achieve significantly improved optoelectronic performance.In this work,we studied the effect of introducing halogen precursors on the structure of classical PbS nanocrystals(NCs)during the synthesis process and realized the preparation of PbS/Pb_(3)S_(2)X_(2) core/shell structure for the first time.The core/shell structure can effectively improve their optical properties.Furthermore,our approach enables the synthesis of Pb_(3)S_(2)Br_(2) that had not yet been reported.Our results not only provide valuable insights into the heterogeneous integration of PbYX and PbY materials to elevate material properties but also provide an effective method for further expanding the preparation of PbYX material systems.展开更多
基金funded by China’s National Social Science Fund,“The effect of community violence exposure on middle school students’social adjustment and its intervention countermeasures”(16BSH102).
文摘This study aimed to investigate the link between the exposure to intimate partner violence(IPV),core self-evaluations(CSE),and psychological adaptation of Chinese adolescents,through analysis of the results from the Survey of Children’s Exposure to Domestic Violence Scale,Core Self-Evaluations Scale,and Strengths and Difficulties Questionnaire,involving a total of 597 Chinese middle school students.It is indicated that the exposure to IPV is positively correlated with lower levels of psychological adaptation and CSE,and CSE is positively correlated with higher levels of psychological adaptation.Mediation analysis revealed that CSE partially mediated the association between the exposure to IPV and psychological adaptation.These results suggest that educators and parents should help adolescents tackle their emotional and behavioral problems by reducing the risk of IPV exposure and increasing their CSE.
文摘This study aims to examine the relationship between authentic leadership and employee proactive behavior. Based on self-determination theory, we argue that such a relationship is sequentially mediated by psychological empowerment and core self-evaluations. In addition, political skill plays a moderating role in the third stage. These hypotheses are validated by a sample of 65 leaders and 275 subordinates from two private enterprises in China's Mainland. Results show that authentic leadership Clime I） influences employees＇ proactive behavior Clime 3） through the psychological empowerment （Time I） and core self-evaluations of employees （Time 2）, and the relationship between core self-evaluations and proactive behavior is positively moderated by employees＇ political skill. In addition, bootstrapping results also verify the moderating role played by employees＇ political skill in the indirect relationship between authentic leadership and proactive behavior through core self-evaluations. Theoretical and managerial implications are further discussed in the light of these findings.
基金The Ministry of Education of China supported this work under the Humanities and Social Sciences Research Project for Young Scholars(Grant No.20YJC890020).
文摘Background:Social anxiety is prevalent among adolescents and severely impacts their mental health and social functioning.This study aims to explore the underlying mechanisms and subgroup differences in adolescent social anxiety to provide a theoretical basis for targeted interventions.Methods:3025 Chinese adolescents(Meanage=13.91±1.60 years;47%male)completed self-report measures of physical activity,core self-evaluation,and social anxiety.Variable-centered analyses employed PROCESS Model 4 with 5000 bootstrap samples;covariates were gender,grade,and place of residence.Person-centered analyses used latent profile analysis in Mplus 8.3 to identify subgroups based on social anxiety item profiles.Results:Variable-centered analyses showed that physical activity had a significant negative association with social anxiety(β=−0.224,p<0.001)and a significant positive association with core self-evaluation(β=0.471,p<0.001);core self-evaluation partially mediated this relationship,accounting for 30%of the total effect.Person-centered analyses revealed an optimal two-profile solution:a low social anxiety profile(89.6%)and a high social anxiety profile(10.4%).The high social anxiety profile reported significantly lower physical activity and lower core self-evaluation than the low social anxiety profile.Conclusions:This study integrates variable-centered and person-centered evidence,identifies physical activity and core self-evaluation as key modifiable factors in reducing social anxiety,providing a theoretical basis for targeted and differentiated interventions.
基金supported by the Education Working Committee of the Xinjiang Uygur Autonomous Region Party Committee(grant number 2023GZYB10).
文摘This study aimed to explore how core self-evaluations and gender influence interpersonal adjustment and depression risk.Participants were 1748 college students(female=59.73%,male=40.27%,mean age=18.71 years,SD=0.78 years).The students completed the Interpersonal Adjustment Scale for College Students,Center for Epidemiological Studies Depression Scale,and Core Self-evaluation Scale.The results of Linear regression and mediated moderated effects modeling revealed that college students with higher interpersonal adjustment and core self-evaluation scores were at lower risk for depression.Core self-evaluation mediated the relationship between interpersonal adjustment and depression in college students for lower risk for depression.Gender moderated the relationship between interpersonal adjustment and core self-evaluation in college students for higher risk for depression in female students.From thesefindings,we conclude that interpersonal adjustment and core self-evaluation are significant for screening depression risk college students.Moreover,female students may benefit from targeted interventions aimed at their interpersonal adjustment for reducing their risk of depression.
基金financially supported by the National Natural Science Foundation of China(grant no.42120104005)Guizhou Provincial 2021 Science and Technology Subsidies(grant no.GZ2021SIG)+1 种基金Guizhou Provincial Science and Technology Projects(grant nos.ZK[2024]087GCC[2023]060)。
文摘The Martian core mainly contains iron,nickel and some light elements.However,controversies remain about the structure and chemical composition of the Martian core due to a lack of samples and marsquake data.Recently,the InSight lander collected long-term marsquake data,which improved the Martian interior structure model.B ased on the preliminary analysis of marsquake data,Mars has a molten liquid core with a radius of around 1700 km.As the Martian core has a smaller density and lower temperature than pure iron at corresponding pressure and temperature conditions,some light elements are introduced to reduce the density and liquidus temperature.With various methods for seismic analysis,in-situ high-pressure and high-temperature experiments,and first-principal calculations,the Martian core composition and evolution models have been updated in the past few years.Here,we review those studies on the light elements in the Martian core from four aspects including(1)high-temperature and high-pressure experiments,(2)marsquake data,(3)mineral physics model with molecular dynamics simulations and(4)cosmochemistry investigation.We discussed the effect of different light elements on the Martian core s density,sound velocity and liquidus temperature.Moreover,the review examines the varieties,abundances and forms of light elements in the Martian core.
基金supported by the fund of State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment(No.DEC8300CG202210353EE280297)the China Postdoctoral Science Foundation(No.2021M692555)+1 种基金the Shaanxi Province Qinchuangyuan‘Scientists+Engineers’Team Building Project(No.2023KXJ-266)the Fundamental Research Funds for the Central Universities(No.xzy012023145)。
文摘Low reactivity and appropriate wettability between molten superalloys and ceramic materials are crucial for the production of high-quality superalloy castings.The sessile-drop experiment was employed to systematically investigate the interfacial reaction and wettability between the 4777DS1 superalloy and SiO_(2)-based ceramic core at various temperatures(1,480℃,1,500℃,1,520℃,and 1,550℃).The wetting behavior and interfacial reaction products at different temperatures were analyzed by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and X-ray diffraction(XRD).The interfacial reaction process and products were discussed,and the thermodynamic behavior and interfacial reaction mechanisms were elucidated.The results demonstrate that the wetting behavior and interfacial reaction between the 4777DS1 alloy and the ceramic core are significantly influenced by temperature.The wettability angle exhibits a trend of initial decrease followed by an increase with rising temperature,reaching a maximum of 139°at 1,480℃,indicating poorer wettability of the 4777DS1 superalloy with the ceramic core and better casting properties at this specific temperature.The most intense interfacial reaction occurs at 1,520℃,resulting in the formation of the main interfacial reaction products such as Al_(2)O_(3),SiO_(2),and HfO_(2).Additionally,some crystal-like products rich in Si and Hf distribute on the reaction layer.
基金supported by the National Social Science Foundation of China(20BSH131).
文摘Internet gaming disorder(IGD)among junior high school students is an increasingly prominent mental health concern.It is important to look for influences behind internet gaming disorder tendency(IGDT)in the junior high school student population.The present study aimed to reveal the explanatory mechanisms underlying the association between parental psychological control(PPC)and internet gaming disorder tendency among junior high school students by testing the mediating role of core self-evaluation(CSE)and the moderating role of intentional self-regulation(ISR).Participants in present study were 735 Chinese junior high school students who completed offline self-report questionnaires on parental psychological control,core self-evaluation,intentional self-regulation,and Internet gaming disorder tendency.Analyses were conducted via mediation and moderated mediation.The results showed that:(1)Parental psychological control was positively related to junior high school students’Internet gaming disorder tendency.Core self-evaluation,and intentional self-regulation were negatively related to junior high school students’Internet gaming disorder tendency,respectively.(2)Core self-evaluation partially mediated the relationship between parental psychological control and junior high school students’Internet gaming disorder tendency.(3)Intentional self-regulation moderated the association between parental psychological control and Internet gaming disorder tendency,as well as the relationships between parental psychological control and core self-evaluation and core self-evaluation and Internet gaming disorder tendency in the mediated model.Based on these findings,we believe that there is a need to weaken parental psychological control,strengthen junior high school students’core self-evaluation and intentional self-regulation,and to recognize the important role of parents as well as their children’s personal positive traits in the healthy development of junior high school students.
文摘The present study discusses the relationship among Chinese adolescents’parental involvement,core self-evaluation,and school adaptation.The Parental Involvement Behavior Questionnaire,Core Self-Evaluations Scale(CSES),and the School Adaptation Inventory were used to survey 1258 Chinese middle school students.The results showed that adolescents’school adaptation was significantly positively correlated with parental involvement and core self-evaluation.Furthermore,parental involvement and core self-evaluation were positively correlated.Mediation analysis found that core self-evaluation had partially mediated the relationship between adolescents’parental involvement and school adaption.Parental involvement could directly affect adolescents’school adaptation and indirectly affect school adaptation through the mediating effect of core self-evaluation.The present study results suggested that parents and educators could improve adolescents’school adaptation by increasing parental involvement and enhancing the adolescents’core self-evaluation.
基金financially supported by the National Natural Science Foundation of China(Nos.42272153 and 42472195)the Research Fund of PetroChina Tarim Oilfield Company(No.671023060003)the Research Fund of China National Petroleum Corporation Limited(No.2023ZZ16YJ04).
文摘Deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures,thus the seepage characteristics are significant for enhancing oil production.This study conducted triaxial compression and permeability tests to investigate the mechanical and seepage properties of tight sandstone.A digital core of tight sandstone was built using Computed Tomography(CT)scanning,which was divided into matrix and pore phases by a pore equivalent diameter threshold.A fluid-solid coupling model was established to investigate the seepage characteristics at micro-scale.The results showed that increasing the confining pressure decreased porosity,permeability,and flow velocity,with the pore phase becoming the dominant seepage channel.Cracks and large pores closed first under increasing pressure,resulted in a steep drop in permeability.However,permeability slightly decreased under high confining pressure,which followed a first-order exponential function.Flow velocity increased with seepage pressure.And the damage mainly occurred in stress-concentration regions under low seepage pressure.Seepage behavior followed linear Darcy flow,the damage emerged at seepage entrances under high pressure,which decreased rock elastic modulus and significantly increased permeability.
文摘This study aimed to explore university students’perceptions on the possession of core competencies for the 21st century.A crosssectional survey research using a self-report questionnaire involving 40 Likert-type items was used to collect data from 5,042 university students in China who voluntarily participated.Analysis with Rasch rating scale model found the data fitted the Rasch model well.The results showed that Chinese university students considered themselves as having acquired most of the competencies to some extent,especially in Character and Civic Literacy and Interpersonal Communication,but less so in Global and International Perspective and Creativity and Problem Solving.
基金supported by the National Natural Science Foundation of China(No.52474355)the Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project),China(Nos.2022JH25/10200003 and 2023JH2/101800058).
文摘The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large deformation during the LCR process and to minimize the thickness of the slab in bending segments,the maximum theoretical reduction amount and the corresponding reduction scheme for the LCR process must be determined.With SPA-H weathering steel as a specific research steel grade,the distributions of tem-perature and deformation fields of a slab with the LCR process were analyzed using a three-dimensional thermal-mechanical finite ele-ment model.High-temperature tensile tests were designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperatures,and a prediction model of the critical strain for two typical cracks,combining the effects of strain rate and temperature,was proposed by incorporating the Zener-Hollomon parameter.The crack risks with different LCR schemes were calculated using the crack risk prediction model,and the maximum theoretical reduction amount for the SPA-H slab with a transverse section of 145 mm×1600 mm was 41.8 mm,with corresponding reduction amounts for Segment 0 to Segment 4 of 15.8,7.3,6.5,6.4,and 5.8 mm,respectively.
基金supported by the National Natural Science Foundation of China(12072136).
文摘Research on the mechanical–electrical properties is crucial for designing and preparing high-temperature superconducting(HTS)cables.Various winding core structures can influence the mechanical–electrical behavior of cables,but the impact of alterations in the winding core structure on the mechanical–electrical behavior of superconducting cables remains unclear.This paper presents a 3D finite element model to predict the performance of three cables with different core structures when subjected to transverse compression and axial tension.The three cables analyzed are CORC(conductor-on-round-core),CORT(conductor-on-round-tube),and HFRC(conductor-on-spiral-tube).A parametric analysis is carried out by varying the core diameter and inner-to-outer diameter ratio.Results indicate that the CORT cable demonstrates better performance in transverse compression compared to the CORC cable,aligning with experimental data.Among the three cables,the HFRC cables exhibit the weakest resistance to transverse deformation.However,the HFRC cable demonstrates superior tensile deformation resistance compared to the CORT cable,provided that the transverse compression properties are maintained.Finite element results also show that the optimum inner-to-outer diameter ratios for achieving the best transverse compression performance are approximately 0.8 for CORT cables and 0.6 for HFRC cables.Meanwhile,the study explores the effect of structural changes in HTS cable winding cores on their electromagnetic properties.It recommends utilizing small tape gaps,lower frequencies,and spiral core construction to minimize eddy losses.The findings presented in this paper offer valuable insights for the commercialization and practical manufacturing of HTS cables.
文摘For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this work.The plate comprises a lattice core located in the middle and several homogeneous orthotropic layers that are symmetrical relative to it.For this purpose,the partial differential equations of motion have been derived based on the first-order shear deformation theory,employing Hamilton’s principle and Von Kármán’s nonlinear displacement-strain relations.Then,the nonlinear partial differential equations of the plate are converted into a time-dependent nonlinear ordinary differential equation(Duffing equation)by applying the Galerkin method.From the solution of this equation,the natural frequencies are extracted.Then,to calculate the non-linear frequencies of the plate,the non-linear equation of the plate has been solved analytically using the method of multiple scales.Finally,the effect of some critical parameters of the system,such as the thickness,height,and different angles of the stiffeners on the linear and nonlinear frequencies,has been analyzed in detail.To confirmthe solution method,the results of this research have been compared with the reported results in the literature and finite elements in ABAQUS,and a perfect match is observed.The results reveal that the geometry and configuration of core ribs strongly affect the natural frequencies of the plate.
基金National Key Research and Development Program of China (No.2021YFC3100800)the National Natural Science Foundation of China (Nos.42407235 and 42271026)+1 种基金the Project of Sanya Yazhou Bay Science and Technology City (No.SCKJ-JYRC-2023-54)supported by the Hefei advanced computing center
文摘Coral reef limestone(CRL)constitutes a distinctive marine carbonate formation with complex mechanical properties.This study investigates the multiscale damage and fracture mechanisms of CRL through integrated experimental testing,digital core technology,and theoretical modelling.Two CRL types with contrasting mesostructures were characterized across three scales.Macroscopically,CRL-I and CRL-II exhibited mean compressive strengths of 8.46 and 5.17 MPa,respectively.Mesoscopically,CRL-I featured small-scale highly interconnected pores,whilst CRL-II developed larger stratified pores with diminished connectivity.Microscopically,both CRL matrices demonstrated remarkable similarity in mineral composition and mechanical properties.A novel voxel average-based digital core scaling methodology was developed to facilitate numerical simulation of cross-scale damage processes,revealing network-progressive failure in CRL-I versus directional-brittle failure in CRL-II.Furthermore,a damage statistical constitutive model based on digital core technology and mesoscopic homogenisation theory established quantitative relationships between microelement strength distribution and macroscopic mechanical behavior.These findings illuminate the fundamental mechanisms through which mesoscopic structure governs the macroscopic mechanical properties of CRL.
文摘Core power is a key parameter of nuclear reactor.Traditionally,the proportional-integralderivative(PID)controllers are used to control the core power.Fractional-order PID(FOPID)controller represents the cutting edge in core power control research.In comparing with the integer-order models,fractional-order models describe the variation of core power more accurately,thus provide a comprehensive and realistic depiction for the power and state changes of reactor core.However,current fractional-order controllers cannot adjust their parameters dynamically to response the environmental changes or demands.In this paper,we aim at the stable control and dynamic responsiveness of core power.Based on the strong selflearning ability of artificial neural network(ANN),we propose a composite controller combining the ANN and FOPID controller.The FOPID controller is firstly designed and a back propagation neural network(BPNN)is then utilized to optimize the parameters of FOPID.It is shown by simulation that the composite controller enables the real-time parameter tuning via ANN and retains the advantage of FOPID controller.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0110300)the National Natural Science Foundation of China(Grant Nos.52372215,92163114,and 52202274)+5 种基金the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20230504)the Special Fund for the"Dual Carbon"Science and Technology Innovation of Jiangsu province(Industrial Prospect and Key Technology Research program)(Grant Nos.BE2022023 and BE2022021)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.21KJA430004)Gusu Innovation and Entre preneurship Leading Talent Program(Grant No.ZXL2022451)the China Postdoctoral Science Foundation(Grant No.2023M732523)supported by Suzhou Key Laboratory of Functional Nano&Soft Materials,Collaborative Innovation Center of Suzhou Nano Science&Technology,the 111 Project.
文摘Lead chalcohalides(PbYX,X=Cl,Br,I;Y=S,Se)is an extension of the classic Pb chalcogenides(PbY).Constructing the heterogeneous integration with PbYX and PbY material systems makes it possible to achieve significantly improved optoelectronic performance.In this work,we studied the effect of introducing halogen precursors on the structure of classical PbS nanocrystals(NCs)during the synthesis process and realized the preparation of PbS/Pb_(3)S_(2)X_(2) core/shell structure for the first time.The core/shell structure can effectively improve their optical properties.Furthermore,our approach enables the synthesis of Pb_(3)S_(2)Br_(2) that had not yet been reported.Our results not only provide valuable insights into the heterogeneous integration of PbYX and PbY materials to elevate material properties but also provide an effective method for further expanding the preparation of PbYX material systems.
