The purpose of this research is to investigate the principals’stress and coping strategies to deal with stress by principals in Bedouin schools in Israel.Data were collected in this research by combining a quantitati...The purpose of this research is to investigate the principals’stress and coping strategies to deal with stress by principals in Bedouin schools in Israel.Data were collected in this research by combining a quantitative and qualitative mixed method.A quantitative research questionnaire was conducted for school principals in 36 schools,in addition to an interview with three principals based on the causes of principal stress and coping mechanisms.Research results show that the principals experiencing balance had the highest mean(M)of 3.28 and standard deviation(SD)of 1.64 on a five-point scale.Principals experiencing moderate stress was parents(M=3.10,SD=0.57)and teachers(M=3.14,SD=0.54),while workload had the lowest mean(M=2.97,SD=0.64).展开更多
Based on the keynote report by Professor Martin Thrupp,this paper discusses the hollowing out of education provision by the state and the permeation of managerialism.It was pointed out that principals and boards of tr...Based on the keynote report by Professor Martin Thrupp,this paper discusses the hollowing out of education provision by the state and the permeation of managerialism.It was pointed out that principals and boards of trustees in socioeconomically advantaged areas may not be willing to share their benefits with schools in less advantaged areas.The new liberal policies have hollowed out state provision of education,so the education system has come to rely heavily on private actors.This paper also presents the current stage of privatization in Japan and the principals’and teachers’perceptions of privatization.展开更多
Rural boarding schools in compulsory education in China have proliferated with school merger program.This paper analyzes the relationship between school belonging and student development and the factors that influence...Rural boarding schools in compulsory education in China have proliferated with school merger program.This paper analyzes the relationship between school belonging and student development and the factors that influence students'sense of belonging in rural boarding schools.The paper examines how principals in rural boarding schools in China can promote student development by building a sense of belonging.The paper argues that building this sense of belonging can serve as a solution to the current problems affecting rural boarding schools,improve the quality of rural primary education,and promote student development.展开更多
The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recogni...The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.展开更多
This paper reports findings from a comparative study of urban vs.rural school principals in China.It is an extension and replication of an earlier study on the profiles and preparation of school leaders in the US and ...This paper reports findings from a comparative study of urban vs.rural school principals in China.It is an extension and replication of an earlier study on the profiles and preparation of school leaders in the US and China.The study illustrates modern portraits-demographic characteristics of urban and rural principals in China,explores their entry perspectives and examines their professional commitment to principalship as a lifelong career.Findings from the comparative study indicate that urban and rural school principals in China differ greatly in their profiles and characteristics.They share similar intrinsic or extrinsic reasons for becoming principals,but they also vary on some key reasons.Unfortunately,most of the principals in our study are not firmly committed to principalship as a lifelong career because of a range of disturbing factors.Findings from this study shed new light on the profiles and preparation of educational leaders in China and offer thoughtful recommendations for change to both Chinese and international education community.展开更多
This paper explores the relationship between leader values and actions in the Chinese context.The Chinese Value Instrument(CVI)and the Strategic Leadership Questionnaire(SLQ)were used as the primary data collection to...This paper explores the relationship between leader values and actions in the Chinese context.The Chinese Value Instrument(CVI)and the Strategic Leadership Questionnaire(SLQ)were used as the primary data collection tools.The CVI was used to measure the presence of ten values:(1)social harmony,(2)benevolence and honesty,(3)initiative and innovation(challenge and creativity),(4)achievement and power,(5)zhongyong(practicality and modesty),(6)stability,(7)familial loyalty,(8)happiness,(9)renqing(sympathy)and guanxi(personal relationships),and(10)freedom and equity.The findings indicate that achievement and initiative were at the low end of the value continuum.Familial loyalty,social harmony,and benevolence were at the high end of the value continuum.The SLQ measured the managing,transforming,bonding,bridging,and bartering actions leaders use to mobilize and gain support from followers.The findings indicate that the Chinese school principal management prototype is formed around transforming and bonding actions.This prototype changes depending on role assignment and school type.A connection between leader values and actions was established with regard to the values of achievement and power,benevolence and honesty,and stability.展开更多
Asymmetric deformation and failure of surrounding rock are frequently observed in mountain tunnels and deep mining roadways,yet the underlying mechanisms remain poorly understood.To investigate asymmetric failure in r...Asymmetric deformation and failure of surrounding rock are frequently observed in mountain tunnels and deep mining roadways,yet the underlying mechanisms remain poorly understood.To investigate asymmetric failure in roadways adjacent to fault structures and mining panels,this study adopts an integrated approach combining theoretical derivation,numerical simulation,and field application,with particular emphasis on the second invariant of the stress deviator(J_(2) )in the surrounding rock.Based on the stress solution for a circular opening,an analytical expression for J_(2)(distortion energy)is derived by considering the reorientation of principal stresses.The study demonstrates that both the increase and reorientation of principal stresses induced by fault–mining interaction jointly govern the spatial distribution of J_(2) and the resulting asymmetric failure behavior.Specifically,the principal stress rotation angle determines the location of J_(2) concentration,whereas the principal stress ratio controls its magnitude.To mitigate asymmetric failure,it is recommended to optimize the J_(2) state through adjustments in roadway size,geometry,and support systems,while simultaneously controlling the asymmetric concentration of stress deviator to enhance roadway stability.This study systematically elucidates the chain mechanism of asymmetric surrounding rock failure driven by principal stress,and further proposes a rational asymmetric joint control strategy,providing theoretical guidance for similar underground engineering conditions.展开更多
Analyzing the driving behavior of autonomous vehicles(AV)in mixed traffic conditions at urban intersections has become increasingly important for improving intersection design,providing infrastructure-based guidance i...Analyzing the driving behavior of autonomous vehicles(AV)in mixed traffic conditions at urban intersections has become increasingly important for improving intersection design,providing infrastructure-based guidance information,and developing capability-enhanced AV perception systems.This study investigated the contributing factors affecting AV driving behavior using theWaymo Open Dataset.Binarized autonomous driving stability metrics,derived via a kernel density estimation,served as the target variables for a random forest classification model.The model’s input variables included 15 factors divided into four types:intersection-related,surrounding object-related,road infrastructure-related,and time-of-day-related types.The random forest classification model was employed to identify the key factors affecting autonomous driving behavior.In addition,the identified factors were further ranked based on feature importance.SHAP analysis was utilized to enhance model interpretability by quantifying the contribution of each factor and identifying their directional impacts.The type of intersection factor was found to have an importance of 0.243 and was the most influential factor on autonomous driving behavior.On average,intersection-related factors had an importance of 0.196,which is approximately a 31.1%margin over the average importance of surrounding object-related factors.Additionally,the surrounding object-related factors that were collected through sensors on the autonomous vehicle had a high degree of feature importance,especially with the number of pedestrians having the highest importance(0.107)of the types of objects.The correlation between these findings can contribute to the development of various treatments to improvemore harmonized AVs’maneuvering with other road users and facilities in urban mixed traffic environments.展开更多
[Objectives]To develop an HPLC fingerprint analysis method for the medicinal material of Lysimachia foenum-graecum Hance,thereby providing a foundation for its quality control.[Methods]Samples of L.foenum-graecum coll...[Objectives]To develop an HPLC fingerprint analysis method for the medicinal material of Lysimachia foenum-graecum Hance,thereby providing a foundation for its quality control.[Methods]Samples of L.foenum-graecum collected from 10 distinct locations in Guangxi were analyzed using HPLC,and chromatographic fingerprints were established.The Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine(2012 Edition)was employed for common peak calibration and similarity evaluation.Additionally,principal component analysis was performed on the common peak area data.[Results]An HPLC fingerprint of L.foenum-graecum was developed,identifying a total of 13 common peaks.Among these,four characteristic components were specifically identified:chlorogenic acid,myricetin,quercetin,and kaempferol.The kaempferol chromatographic peak,exhibiting good resolution and a stable peak shape,was selected as the reference peak.The similarity indices between the fingerprints of the 10 sample batches and the reference fingerprint ranged from 0.954 to 0.995,indicating a relatively high consistency in the chemical composition of L.foenum-graecum from different origins.Principal component analysis identified two principal components,which together accounted for 89.45%of the cumulative variance,effectively capturing the primary chemical differences among the samples.[Conclusions]The established HPLC fingerprint method is straightforward to implement,stable,reliable,and exhibits high specificity.When combined with similarity evaluation and principal component analysis,it offers a scientific basis for developing quality standards for L.foenum-graecum medicinal materials.展开更多
The Toraja Highlands,encompassing Tana Toraja and North Toraja,form the strategic upper reaches of the Saddang Watershed in South Sulawesi,where steep terrain,active land-cover change,and high ecological sensitivity c...The Toraja Highlands,encompassing Tana Toraja and North Toraja,form the strategic upper reaches of the Saddang Watershed in South Sulawesi,where steep terrain,active land-cover change,and high ecological sensitivity converge.This study addresses the need for an objective and validated ecological sensitivity map to support sustainable mountain watershed management.We construct an ecological sensitivity index based on principal component analysis using four key indicators:land cover,vegetation density(NDVI),slope,and rainfall,and evaluate its reliability through multi-source validation.Inputs integrate national elevation models,Landsat 8 imagery,and satellite-derived rainfall.Rainfall represents a multi-year climatology for 2015–2024,whereas land cover and NDVI reflect recent surface conditions derived from a cloud-free 2024 composite.The resulting sensitivity zonation indicates that 41.10%of Tana Toraja and 67.11%of North Toraja fall into the very high sensitivity class,concentrated on steep slopes and intensively converted landscapes.Eventbased spatial cross-validation against independent landslide records yields overall accuracies of 67.65%and 66.67%,while field verification produces Kappa values of 0.847 and 0.871.Stakeholder appraisal further corroborates the mapped patterns.Together,these convergent lines of evidence identify priority areas for reforestation,soil conservation,slope stabilization,and sustainable watershed management.The transparent and reproducible workflow supports evidence-based risk reduction and resilience building in the upper reaches of the Saddang Watershed.展开更多
Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear stre...Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear strength.To further investigate this phenomenon,this study investigates the shear behaviour of rocks with different shear surface integrities under the influenceof different stress paths through laboratory tests and numerical simulations.The results indicate that the shear strength depends on the stress path and a decrease in the shear surface integrity reduces the degree of dependence.The cohesion and friction angle of the Mohr‒Coulomb criterion decrease with weakening of the shear surface integrity.For different stress paths,the direct shear strength is always greater than that of other shear stress paths.The pattern of changes in the acoustic emission count and cumulative count indirectly reflectsthe above findings.Numerical simulations further indicate that the different principal stress states and normal suppression effects during the shearing process lead to changes in the factors of crack propagation,resulting in different mechanical behaviours under various stress paths.For rocks with different integrity levels,the main reason for the different path dependences of shear strength is that the size of the area affected by shear is different.Shear failure will concentrate on the shear plane when the normal inhibition effect is greater.This study explores the mechanism of rock shear behaviour,providing a theoretical basis for establishing more accurate constitutive models and strength criteria.展开更多
To improve the accuracy of rockburst risk evaluation in mining and tunnelling engineering,the influence of intermediate principal stress σ_(2) deserves further consideration,which has been neglected in general predic...To improve the accuracy of rockburst risk evaluation in mining and tunnelling engineering,the influence of intermediate principal stress σ_(2) deserves further consideration,which has been neglected in general prediction frameworks.This study employs an integrated approach that combines true-triaxial unloading experiments with three-dimensional grain-based discrete element modeling(PFC3D-GBM)to examine the effects of σ_(2) on strain systematically burst and elucidate the underlying mechanisms.Through this dual experimental–numerical methodology,the strainburst characteristics under varying σ_(2) are analyzed in detail regarding mechanical responses,failure evolution and patterns,microscope fracture mechanisms,and energy partitioning.The results indicate that elevated σ_(2) can enhance the bearing capacity of rock,thereby necessitating a higher stress condition required for strainburst.However,it also enlarges the potential strainburst intensity,manifesting as deeper rockburst pits and more violent ejection of rock fragments.An increasing σ_(2) facilitates the microscope transgranular fractures,inhibits intergranular tensile fractures,and raises the kinetic energy conversion ratio slightly.It affects the intensity of strainburst through the following mechanisms,including the increase of energy storage limit,the intensification of Poisson effect for lateral expansion,and the enhancement of the transgranular fracturing mechanism.In practical engineering,the depth and range of support needs to be ensured under high σ_(2) conditions,and it is recommended to use prestressing techniques to control the development of significant slabbing.展开更多
Crassostrea gigas has good taste and high nutritional value;however,there are few assessments of comprehensive and panoramic analyses of the nutritional quality of the northern oyster.To study the nutritional characte...Crassostrea gigas has good taste and high nutritional value;however,there are few assessments of comprehensive and panoramic analyses of the nutritional quality of the northern oyster.To study the nutritional characteristics of C.gigas from different sources(ploidy,region,size,and culture mode),C.gigas from various ploidy(diploid and triploid),regions(Rushan,Off-site fattening,and Rongcheng),sizes(small,medium,and large)and culture modes(nearshore and offshore)were selected for comparative analyses.The nutritional components(moisture,protein,fat,and mineral),flavor substances(taste amino acids,nucleotides,and succinic acid),and functional indices(eicosapentaenoic acid(EPA),docosahexaenoic acid(DHA),and taurine)of C.gigas were determined.Principal component analysis(PCA)was used to comprehensively evaluate the oysters and investigate the variations in nutritional quality.The PCA results indicate that protein,essential fatty acids,selenium,zinc,taste amino acids,taurine,EPA,and DHA were core components contributing to 82.25%of the cumulative variance,providing a more comprehensive reflection of the nutrient composition of C.gigas.The extensive quality rankings for the C.gigas were as follows:diploid>triploid,Rushan>fattening>Rongcheng,medium>large>small,and offshore>nearshore.The score rank revealed that diploid oysters of medium-size from Rushan demonstrated superior nutritional quality compared to other tested samples.This is the first comprehensive and systematic investigation of C.gigas in northern China to reveal the feature of nutrients,flavor,and functional components.The study provided data support for the culture,consumption,processing,research,and nutritional quality improvement of oyster industry.展开更多
Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when ta...Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when tackling high-dimensional optimization challenges.To effectively address these challenges,this study introduces cooperative metaheuristics integrating dynamic dimension reduction(DR).Building upon particle swarm optimization(PSO)and differential evolution(DE),the proposed cooperative methods C-PSO and C-DE are developed.In the proposed methods,the modified principal components analysis(PCA)is utilized to reduce the dimension of design variables,thereby decreasing computational costs.The dynamic DR strategy implements periodic execution of modified PCA after a fixed number of iterations,resulting in the important dimensions being dynamically identified.Compared with the static one,the dynamic DR strategy can achieve precise identification of important dimensions,thereby enabling accelerated convergence toward optimal solutions.Furthermore,the influence of cumulative contribution rate thresholds on optimization problems with different dimensions is investigated.Metaheuristic algorithms(PSO,DE)and cooperative metaheuristics(C-PSO,C-DE)are examined by 15 benchmark functions and two engineering design problems(speed reducer and composite pressure vessel).Comparative results demonstrate that the cooperative methods achieve significantly superior performance compared to standard methods in both solution accuracy and computational efficiency.Compared to standard metaheuristic algorithms,cooperative metaheuristics achieve a reduction in computational cost of at least 40%.The cooperative metaheuristics can be effectively used to tackle both high-dimensional unconstrained and constrained optimization problems.展开更多
The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of...The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.展开更多
Accurate assessment of site quality in coastal Casuarina equisetifolia(C.equisetifolia)plantations is essential for enhancing the protective function of shelterbelts and implementing site-specific afforestation strate...Accurate assessment of site quality in coastal Casuarina equisetifolia(C.equisetifolia)plantations is essential for enhancing the protective function of shelterbelts and implementing site-specific afforestation strategies.However,traditional ground-based surveys are limited in spatial coverage and efficiency,hindering effective forest management.To overcome these limitations,this study developed an integrated assessment framework that couples ground-based modeling with remote sensing inversion to achieve large-scale site quality mapping.Field investigations on Pingtan Island,Fujian Province,China,were used to establish a ground-based evaluation model.Soil fertility was quantified using Principal Component Analysis(PCA),and principal components were classified into discrete fertility grades through K-means clustering.These grades,together with topographic variables,were incorporated into a site quality classification model constructed using Quantification Theory I.The point-based model was subsequently extrapolated using Landsat 9 imagery to generate a spatially continuous site quality map.Spatial autocorrelation(Moran’s Ⅰ)and LISA clustering were further employed to interpret spatial patterns.Results indicate that coastal sandy soils in the study area are generally nutrient-poor,with tree growth primarily constrained by total nitrogen,organic matter,available phosphorus,and total phosphorus.The five most influential site factors,ranked by importance,are soil fertility,distance from the coastline,aspect,slope gradient,and elevation.Optimal conditions for C.equisetifolia growth include fertile soil,location>1000 m from the coastline,south-facing or semi-sunny slopes,slope gradients<15°,and elevations between 10-100 m.Only 11.94%of the area was classified as high-quality(Grade I),while 61.74%fell into moderate or poor grades(Grades Ⅲ and Ⅳ),indicating that most plantations are located on suboptimal sites.This study provides scientific support for improving the precision and sustainability of coastal shelterbelt planning and management,offering practical insights for afforestation strategies,forest restoration,and ecological forestry development in coastal zones.展开更多
Traditional multivariate parametric control charts often perform inadequately in detecting shifts in the covariance matrix when the data deviate from normality.In this paper,we propose a multivariate nonparametric exp...Traditional multivariate parametric control charts often perform inadequately in detecting shifts in the covariance matrix when the data deviate from normality.In this paper,we propose a multivariate nonparametric exponentially weighted moving average(SGLGEWMA)control chart,incorporating a Sparse Group Lasso penalty,which is capable of detecting shifts in the covariance matrix across a wide range of data types,including discrete,continuous,and mixed distributions.The proposed approach projects multivariate data into a Euclidean space and then computes an approximate Alt’s likelihood ratio,regularized via the Sparse Group Lasso.The resulting EWMA statistic monitors process shifts.Monte Carlo simulations demonstrate that SGLGEWMA outperforms both the Lasso-based LGShewhart and the Ridge-based RGEWMA control charts under various distributions,with enhanced efficacy in high-dimensional scenarios.Sensitivity analyses are performed on the tuning parameters(λ_(1),λ_(2))and smoothing parameterρ,to evaluate their impact on monitoring performance.Additionally,a simulation study and an illustrative example involving covariance monitoring in wafer semiconductor manufacturing are presented to demonstrate the practical application of the proposed chart.Empirical results confirm that the proposed control chart promptly identifies abnormal fluctuations and issues timely alerts,highlighting both its theoretical significance and practical utility.展开更多
Dendritic spines are small protrusions along dendrites that contain most of the excitatory synapses in principal neurons,playing a crucial role in neuronal function by creating a compartmentalized environment for sign...Dendritic spines are small protrusions along dendrites that contain most of the excitatory synapses in principal neurons,playing a crucial role in neuronal function by creating a compartmentalized environment for signal transduction.The plasticity of spine morphologies provides a tunable handle to regulate calcium signal dynamics,allowing rapid regulation of protein expression necessary to establish and maintain synapses(Cornejo et al.,2022).If excitatory inputs were to be located primarily on dendritic shafts,dendrites would frequently short-circuit,preventing voltage signals from propagating(Cornejo et al.,2022).It is thus not surprising that the structural plasticity of dendritic spines is closely linked to synaptic plasticity and memory formation(Berry and Nedivi,2017).While comprehensive in vitro studies have been conducted,in vivo studies that directly tackle the mechanism of dendritic transport and translation in regulating spine plasticity spatiotemporally are limited.展开更多
Attending one of China’s most prestigious institutions of higher learning, Peking University (PKU), is a dream for the vast majority of China’s middle school graduates. On November 16, the university released a list...Attending one of China’s most prestigious institutions of higher learning, Peking University (PKU), is a dream for the vast majority of China’s middle school graduates. On November 16, the university released a list of 39 senior middle schools across the country whose principals have展开更多
文摘The purpose of this research is to investigate the principals’stress and coping strategies to deal with stress by principals in Bedouin schools in Israel.Data were collected in this research by combining a quantitative and qualitative mixed method.A quantitative research questionnaire was conducted for school principals in 36 schools,in addition to an interview with three principals based on the causes of principal stress and coping mechanisms.Research results show that the principals experiencing balance had the highest mean(M)of 3.28 and standard deviation(SD)of 1.64 on a five-point scale.Principals experiencing moderate stress was parents(M=3.10,SD=0.57)and teachers(M=3.14,SD=0.54),while workload had the lowest mean(M=2.97,SD=0.64).
文摘Based on the keynote report by Professor Martin Thrupp,this paper discusses the hollowing out of education provision by the state and the permeation of managerialism.It was pointed out that principals and boards of trustees in socioeconomically advantaged areas may not be willing to share their benefits with schools in less advantaged areas.The new liberal policies have hollowed out state provision of education,so the education system has come to rely heavily on private actors.This paper also presents the current stage of privatization in Japan and the principals’and teachers’perceptions of privatization.
文摘Rural boarding schools in compulsory education in China have proliferated with school merger program.This paper analyzes the relationship between school belonging and student development and the factors that influence students'sense of belonging in rural boarding schools.The paper examines how principals in rural boarding schools in China can promote student development by building a sense of belonging.The paper argues that building this sense of belonging can serve as a solution to the current problems affecting rural boarding schools,improve the quality of rural primary education,and promote student development.
文摘The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.
文摘This paper reports findings from a comparative study of urban vs.rural school principals in China.It is an extension and replication of an earlier study on the profiles and preparation of school leaders in the US and China.The study illustrates modern portraits-demographic characteristics of urban and rural principals in China,explores their entry perspectives and examines their professional commitment to principalship as a lifelong career.Findings from the comparative study indicate that urban and rural school principals in China differ greatly in their profiles and characteristics.They share similar intrinsic or extrinsic reasons for becoming principals,but they also vary on some key reasons.Unfortunately,most of the principals in our study are not firmly committed to principalship as a lifelong career because of a range of disturbing factors.Findings from this study shed new light on the profiles and preparation of educational leaders in China and offer thoughtful recommendations for change to both Chinese and international education community.
文摘This paper explores the relationship between leader values and actions in the Chinese context.The Chinese Value Instrument(CVI)and the Strategic Leadership Questionnaire(SLQ)were used as the primary data collection tools.The CVI was used to measure the presence of ten values:(1)social harmony,(2)benevolence and honesty,(3)initiative and innovation(challenge and creativity),(4)achievement and power,(5)zhongyong(practicality and modesty),(6)stability,(7)familial loyalty,(8)happiness,(9)renqing(sympathy)and guanxi(personal relationships),and(10)freedom and equity.The findings indicate that achievement and initiative were at the low end of the value continuum.Familial loyalty,social harmony,and benevolence were at the high end of the value continuum.The SLQ measured the managing,transforming,bonding,bridging,and bartering actions leaders use to mobilize and gain support from followers.The findings indicate that the Chinese school principal management prototype is formed around transforming and bonding actions.This prototype changes depending on role assignment and school type.A connection between leader values and actions was established with regard to the values of achievement and power,benevolence and honesty,and stability.
基金supported by the National Natural Science Foundation of China(Grant No.52274148)the Natural Science Foundation of Hebei Province(Grant No.E2023402103)+1 种基金the Science Research Project of Hebei Education Department(Grant No.QN2025247)Handan Science and Technology R&D Project(Grant No.23422093047)。
文摘Asymmetric deformation and failure of surrounding rock are frequently observed in mountain tunnels and deep mining roadways,yet the underlying mechanisms remain poorly understood.To investigate asymmetric failure in roadways adjacent to fault structures and mining panels,this study adopts an integrated approach combining theoretical derivation,numerical simulation,and field application,with particular emphasis on the second invariant of the stress deviator(J_(2) )in the surrounding rock.Based on the stress solution for a circular opening,an analytical expression for J_(2)(distortion energy)is derived by considering the reorientation of principal stresses.The study demonstrates that both the increase and reorientation of principal stresses induced by fault–mining interaction jointly govern the spatial distribution of J_(2) and the resulting asymmetric failure behavior.Specifically,the principal stress rotation angle determines the location of J_(2) concentration,whereas the principal stress ratio controls its magnitude.To mitigate asymmetric failure,it is recommended to optimize the J_(2) state through adjustments in roadway size,geometry,and support systems,while simultaneously controlling the asymmetric concentration of stress deviator to enhance roadway stability.This study systematically elucidates the chain mechanism of asymmetric surrounding rock failure driven by principal stress,and further proposes a rational asymmetric joint control strategy,providing theoretical guidance for similar underground engineering conditions.
基金supported by Korea Institute of Police Technology(KIPoT)grant funded by the Korea government(KNPA)(Project Name:Development of Lv.4 Driving Ability Evaluation Technology for Autonomous Vehicles Based on Real Roads/Project Number:RS-2023-00238253).
文摘Analyzing the driving behavior of autonomous vehicles(AV)in mixed traffic conditions at urban intersections has become increasingly important for improving intersection design,providing infrastructure-based guidance information,and developing capability-enhanced AV perception systems.This study investigated the contributing factors affecting AV driving behavior using theWaymo Open Dataset.Binarized autonomous driving stability metrics,derived via a kernel density estimation,served as the target variables for a random forest classification model.The model’s input variables included 15 factors divided into four types:intersection-related,surrounding object-related,road infrastructure-related,and time-of-day-related types.The random forest classification model was employed to identify the key factors affecting autonomous driving behavior.In addition,the identified factors were further ranked based on feature importance.SHAP analysis was utilized to enhance model interpretability by quantifying the contribution of each factor and identifying their directional impacts.The type of intersection factor was found to have an importance of 0.243 and was the most influential factor on autonomous driving behavior.On average,intersection-related factors had an importance of 0.196,which is approximately a 31.1%margin over the average importance of surrounding object-related factors.Additionally,the surrounding object-related factors that were collected through sensors on the autonomous vehicle had a high degree of feature importance,especially with the number of pedestrians having the highest importance(0.107)of the types of objects.The correlation between these findings can contribute to the development of various treatments to improvemore harmonized AVs’maneuvering with other road users and facilities in urban mixed traffic environments.
基金Supported by 2023 Self-funded Research Project of the Guangxi Zhuang Autonomous Region Administration of Traditional Chinese Medicine(GXZYL20230369)2022 Internal Talent Research Project of Affiliated Hospital of Youjiang Medical University for Nationalities(Y202210319).
文摘[Objectives]To develop an HPLC fingerprint analysis method for the medicinal material of Lysimachia foenum-graecum Hance,thereby providing a foundation for its quality control.[Methods]Samples of L.foenum-graecum collected from 10 distinct locations in Guangxi were analyzed using HPLC,and chromatographic fingerprints were established.The Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine(2012 Edition)was employed for common peak calibration and similarity evaluation.Additionally,principal component analysis was performed on the common peak area data.[Results]An HPLC fingerprint of L.foenum-graecum was developed,identifying a total of 13 common peaks.Among these,four characteristic components were specifically identified:chlorogenic acid,myricetin,quercetin,and kaempferol.The kaempferol chromatographic peak,exhibiting good resolution and a stable peak shape,was selected as the reference peak.The similarity indices between the fingerprints of the 10 sample batches and the reference fingerprint ranged from 0.954 to 0.995,indicating a relatively high consistency in the chemical composition of L.foenum-graecum from different origins.Principal component analysis identified two principal components,which together accounted for 89.45%of the cumulative variance,effectively capturing the primary chemical differences among the samples.[Conclusions]The established HPLC fingerprint method is straightforward to implement,stable,reliable,and exhibits high specificity.When combined with similarity evaluation and principal component analysis,it offers a scientific basis for developing quality standards for L.foenum-graecum medicinal materials.
基金funded by the Ministry of Higher Education,Science and Technology,Republic of Indonesia through the Indonesia Collaborative Research(Riset Kolaborasi Indonesia)grant(Number:01319/UN4.22/PT.01.03/2025)。
文摘The Toraja Highlands,encompassing Tana Toraja and North Toraja,form the strategic upper reaches of the Saddang Watershed in South Sulawesi,where steep terrain,active land-cover change,and high ecological sensitivity converge.This study addresses the need for an objective and validated ecological sensitivity map to support sustainable mountain watershed management.We construct an ecological sensitivity index based on principal component analysis using four key indicators:land cover,vegetation density(NDVI),slope,and rainfall,and evaluate its reliability through multi-source validation.Inputs integrate national elevation models,Landsat 8 imagery,and satellite-derived rainfall.Rainfall represents a multi-year climatology for 2015–2024,whereas land cover and NDVI reflect recent surface conditions derived from a cloud-free 2024 composite.The resulting sensitivity zonation indicates that 41.10%of Tana Toraja and 67.11%of North Toraja fall into the very high sensitivity class,concentrated on steep slopes and intensively converted landscapes.Eventbased spatial cross-validation against independent landslide records yields overall accuracies of 67.65%and 66.67%,while field verification produces Kappa values of 0.847 and 0.871.Stakeholder appraisal further corroborates the mapped patterns.Together,these convergent lines of evidence identify priority areas for reforestation,soil conservation,slope stabilization,and sustainable watershed management.The transparent and reproducible workflow supports evidence-based risk reduction and resilience building in the upper reaches of the Saddang Watershed.
基金support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX24_2822)the Graduate Innovation Program of China University of Mining and Technology(Grant No.2024WLKXJ205)the National Natural Science Foundation of China(Grant No.52474157).
文摘Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear strength.To further investigate this phenomenon,this study investigates the shear behaviour of rocks with different shear surface integrities under the influenceof different stress paths through laboratory tests and numerical simulations.The results indicate that the shear strength depends on the stress path and a decrease in the shear surface integrity reduces the degree of dependence.The cohesion and friction angle of the Mohr‒Coulomb criterion decrease with weakening of the shear surface integrity.For different stress paths,the direct shear strength is always greater than that of other shear stress paths.The pattern of changes in the acoustic emission count and cumulative count indirectly reflectsthe above findings.Numerical simulations further indicate that the different principal stress states and normal suppression effects during the shearing process lead to changes in the factors of crack propagation,resulting in different mechanical behaviours under various stress paths.For rocks with different integrity levels,the main reason for the different path dependences of shear strength is that the size of the area affected by shear is different.Shear failure will concentrate on the shear plane when the normal inhibition effect is greater.This study explores the mechanism of rock shear behaviour,providing a theoretical basis for establishing more accurate constitutive models and strength criteria.
基金supported by the National Natural Science Foundation of China(No.42507210)the Fundamental Research Funds for the Central Universities(No.2025XJSB01)+1 种基金the State Key Laboratory for Tunnel Engineering(No.SKLTEK202421)the Foundation of Key Laboratory of Deep Coal Resource Mining(China University of Mining and Technology),Ministry of Education(No.KLDCRMMOE24KF11).
文摘To improve the accuracy of rockburst risk evaluation in mining and tunnelling engineering,the influence of intermediate principal stress σ_(2) deserves further consideration,which has been neglected in general prediction frameworks.This study employs an integrated approach that combines true-triaxial unloading experiments with three-dimensional grain-based discrete element modeling(PFC3D-GBM)to examine the effects of σ_(2) on strain systematically burst and elucidate the underlying mechanisms.Through this dual experimental–numerical methodology,the strainburst characteristics under varying σ_(2) are analyzed in detail regarding mechanical responses,failure evolution and patterns,microscope fracture mechanisms,and energy partitioning.The results indicate that elevated σ_(2) can enhance the bearing capacity of rock,thereby necessitating a higher stress condition required for strainburst.However,it also enlarges the potential strainburst intensity,manifesting as deeper rockburst pits and more violent ejection of rock fragments.An increasing σ_(2) facilitates the microscope transgranular fractures,inhibits intergranular tensile fractures,and raises the kinetic energy conversion ratio slightly.It affects the intensity of strainburst through the following mechanisms,including the increase of energy storage limit,the intensification of Poisson effect for lateral expansion,and the enhancement of the transgranular fracturing mechanism.In practical engineering,the depth and range of support needs to be ensured under high σ_(2) conditions,and it is recommended to use prestressing techniques to control the development of significant slabbing.
基金Supported by the Central Public-interest Scientific Institution Basal Research Fund,YSFRI,CAFS(No.20603022024016)the Central Public-interest Scientific Institution Basal Research Fund,CAFS(Nos.2023TD52,2023TD76)the earmarked fund for CARS(No.CARS-49)。
文摘Crassostrea gigas has good taste and high nutritional value;however,there are few assessments of comprehensive and panoramic analyses of the nutritional quality of the northern oyster.To study the nutritional characteristics of C.gigas from different sources(ploidy,region,size,and culture mode),C.gigas from various ploidy(diploid and triploid),regions(Rushan,Off-site fattening,and Rongcheng),sizes(small,medium,and large)and culture modes(nearshore and offshore)were selected for comparative analyses.The nutritional components(moisture,protein,fat,and mineral),flavor substances(taste amino acids,nucleotides,and succinic acid),and functional indices(eicosapentaenoic acid(EPA),docosahexaenoic acid(DHA),and taurine)of C.gigas were determined.Principal component analysis(PCA)was used to comprehensively evaluate the oysters and investigate the variations in nutritional quality.The PCA results indicate that protein,essential fatty acids,selenium,zinc,taste amino acids,taurine,EPA,and DHA were core components contributing to 82.25%of the cumulative variance,providing a more comprehensive reflection of the nutrient composition of C.gigas.The extensive quality rankings for the C.gigas were as follows:diploid>triploid,Rushan>fattening>Rongcheng,medium>large>small,and offshore>nearshore.The score rank revealed that diploid oysters of medium-size from Rushan demonstrated superior nutritional quality compared to other tested samples.This is the first comprehensive and systematic investigation of C.gigas in northern China to reveal the feature of nutrients,flavor,and functional components.The study provided data support for the culture,consumption,processing,research,and nutritional quality improvement of oyster industry.
基金funded by National Natural Science Foundation of China(Nos.12402142,11832013 and 11572134)Natural Science Foundation of Hubei Province(No.2024AFB235)+1 种基金Hubei Provincial Department of Education Science and Technology Research Project(No.Q20221714)the Opening Foundation of Hubei Key Laboratory of Digital Textile Equipment(Nos.DTL2023019 and DTL2022012).
文摘Owing to their global search capabilities and gradient-free operation,metaheuristic algorithms are widely applied to a wide range of optimization problems.However,their computational demands become prohibitive when tackling high-dimensional optimization challenges.To effectively address these challenges,this study introduces cooperative metaheuristics integrating dynamic dimension reduction(DR).Building upon particle swarm optimization(PSO)and differential evolution(DE),the proposed cooperative methods C-PSO and C-DE are developed.In the proposed methods,the modified principal components analysis(PCA)is utilized to reduce the dimension of design variables,thereby decreasing computational costs.The dynamic DR strategy implements periodic execution of modified PCA after a fixed number of iterations,resulting in the important dimensions being dynamically identified.Compared with the static one,the dynamic DR strategy can achieve precise identification of important dimensions,thereby enabling accelerated convergence toward optimal solutions.Furthermore,the influence of cumulative contribution rate thresholds on optimization problems with different dimensions is investigated.Metaheuristic algorithms(PSO,DE)and cooperative metaheuristics(C-PSO,C-DE)are examined by 15 benchmark functions and two engineering design problems(speed reducer and composite pressure vessel).Comparative results demonstrate that the cooperative methods achieve significantly superior performance compared to standard methods in both solution accuracy and computational efficiency.Compared to standard metaheuristic algorithms,cooperative metaheuristics achieve a reduction in computational cost of at least 40%.The cooperative metaheuristics can be effectively used to tackle both high-dimensional unconstrained and constrained optimization problems.
基金supported by Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012378)Natural Science Foundation of China(Nos.52471093,52274367)+3 种基金fund of the State Key Laboratory of Solidification Processing in NPU(No.2025‐QZ‐03)the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University(No.PF2025041)Fundamental Research Projects of Science&Technology Innovation and development Plan in Yantai City(No.2024JCYJ099)project(No.ZR2024QE213)supported by Shandong Provincial Natural Science Foundation.
文摘The pursuit of simultaneously high wear resistance and excellent lubrication in multi‐principal element alloy(MPEA)composites is often hindered by a fundamental trade‐off,which is exacerbated by the agglomeration of high‐content graphene reinforcements.This compromise becomes particularly severe in composites with high‐content graphene reinforcements,whose agglomeration leads to embrittlement and lubrication failure.Here,a flake powder-metallurgy strategy is developed to construct a self‐assembled lamellar structure in graphene/CoCrNi MPEA composites(Gr/MPEA_(AL)).This approach enables the uniform dispersion of a high graphene content(3.0 wt%),which is unattainable by conventional methods.The resulting composite exhibits a rare dual enhancement in performance:an order‐of‐magnitude improvement in wear resistance coupled with a low coefficient of friction.Intriguingly,the tribological behavior shows significant anisotropy,with optimal performance observed when sliding perpendicular to the lamellae.Through a multi‐scale methodology combining molecular dynamics simulations,finite element analysis,and systematic experiments,it is revealed that this exceptional performance stems from the synergy of high‐density deformation nanotwins,efficient strain delocalization,and abundant graphene‐derived lubricating sites.This work establishes a general paradigm for designing composite architectures that reconcile traditionally incompatible properties,offering broad implications for developing next‐generation structural materials with integrated mechanical robustness and surface functionality for safety‐critical applications.
基金supported by University Key Lab for Geomatics Technology&Optimize Resources Utilization in Fujian Province(KJG20104A)Fujian Forestry Science and Technology project(2023FKJ15)Fuzhou Forestry Science and Technology Research Project(2130206).
文摘Accurate assessment of site quality in coastal Casuarina equisetifolia(C.equisetifolia)plantations is essential for enhancing the protective function of shelterbelts and implementing site-specific afforestation strategies.However,traditional ground-based surveys are limited in spatial coverage and efficiency,hindering effective forest management.To overcome these limitations,this study developed an integrated assessment framework that couples ground-based modeling with remote sensing inversion to achieve large-scale site quality mapping.Field investigations on Pingtan Island,Fujian Province,China,were used to establish a ground-based evaluation model.Soil fertility was quantified using Principal Component Analysis(PCA),and principal components were classified into discrete fertility grades through K-means clustering.These grades,together with topographic variables,were incorporated into a site quality classification model constructed using Quantification Theory I.The point-based model was subsequently extrapolated using Landsat 9 imagery to generate a spatially continuous site quality map.Spatial autocorrelation(Moran’s Ⅰ)and LISA clustering were further employed to interpret spatial patterns.Results indicate that coastal sandy soils in the study area are generally nutrient-poor,with tree growth primarily constrained by total nitrogen,organic matter,available phosphorus,and total phosphorus.The five most influential site factors,ranked by importance,are soil fertility,distance from the coastline,aspect,slope gradient,and elevation.Optimal conditions for C.equisetifolia growth include fertile soil,location>1000 m from the coastline,south-facing or semi-sunny slopes,slope gradients<15°,and elevations between 10-100 m.Only 11.94%of the area was classified as high-quality(Grade I),while 61.74%fell into moderate or poor grades(Grades Ⅲ and Ⅳ),indicating that most plantations are located on suboptimal sites.This study provides scientific support for improving the precision and sustainability of coastal shelterbelt planning and management,offering practical insights for afforestation strategies,forest restoration,and ecological forestry development in coastal zones.
基金Sponsored by the National Natural Science Foundation of China[grant number 12571305]the Natural Science Foundation of Shanghai[grant number 25ZR1401113].
文摘Traditional multivariate parametric control charts often perform inadequately in detecting shifts in the covariance matrix when the data deviate from normality.In this paper,we propose a multivariate nonparametric exponentially weighted moving average(SGLGEWMA)control chart,incorporating a Sparse Group Lasso penalty,which is capable of detecting shifts in the covariance matrix across a wide range of data types,including discrete,continuous,and mixed distributions.The proposed approach projects multivariate data into a Euclidean space and then computes an approximate Alt’s likelihood ratio,regularized via the Sparse Group Lasso.The resulting EWMA statistic monitors process shifts.Monte Carlo simulations demonstrate that SGLGEWMA outperforms both the Lasso-based LGShewhart and the Ridge-based RGEWMA control charts under various distributions,with enhanced efficacy in high-dimensional scenarios.Sensitivity analyses are performed on the tuning parameters(λ_(1),λ_(2))and smoothing parameterρ,to evaluate their impact on monitoring performance.Additionally,a simulation study and an illustrative example involving covariance monitoring in wafer semiconductor manufacturing are presented to demonstrate the practical application of the proposed chart.Empirical results confirm that the proposed control chart promptly identifies abnormal fluctuations and issues timely alerts,highlighting both its theoretical significance and practical utility.
基金supported by the National Natural Science Foundation of China(NSFC/RGC/JRF N_HKU735/21)Research Grant Council of Hong Kong,China(17102120,17108821,17103922,C1024-22GF,C7074-21G)+1 种基金Health and Medical Research Fund(HMRF 09200966)(to CSWL)FRQS Postdoctoral Fellowship(to AHKF).
文摘Dendritic spines are small protrusions along dendrites that contain most of the excitatory synapses in principal neurons,playing a crucial role in neuronal function by creating a compartmentalized environment for signal transduction.The plasticity of spine morphologies provides a tunable handle to regulate calcium signal dynamics,allowing rapid regulation of protein expression necessary to establish and maintain synapses(Cornejo et al.,2022).If excitatory inputs were to be located primarily on dendritic shafts,dendrites would frequently short-circuit,preventing voltage signals from propagating(Cornejo et al.,2022).It is thus not surprising that the structural plasticity of dendritic spines is closely linked to synaptic plasticity and memory formation(Berry and Nedivi,2017).While comprehensive in vitro studies have been conducted,in vivo studies that directly tackle the mechanism of dendritic transport and translation in regulating spine plasticity spatiotemporally are limited.
文摘Attending one of China’s most prestigious institutions of higher learning, Peking University (PKU), is a dream for the vast majority of China’s middle school graduates. On November 16, the university released a list of 39 senior middle schools across the country whose principals have
