Sudden and unforeseen seismic failures of coal mine overburden(OB)dump slopes interrupt mining operations,cause loss of lives and delay the production of coal.Consideration of the spatial heterogeneity of OB dump mate...Sudden and unforeseen seismic failures of coal mine overburden(OB)dump slopes interrupt mining operations,cause loss of lives and delay the production of coal.Consideration of the spatial heterogeneity of OB dump materials is imperative for an adequate evaluation of the seismic stability of OB dump slopes.In this study,pseudo-static seismic stability analyses are carried out for an OB dump slope by considering the material parameters obtained from an insitu field investigation.Spatial heterogeneity is simulated through use of the random finite element method(RFEM)and the random limit equilibrium method(RLEM)and a comparative study is presented.Combinations of horizontal and vertical spatial correlation lengths were considered for simulating isotropic and anisotropic random fields within the OB dump slope.Seismic performances of the slope have been reported through the probability of failure and reliability index.It was observed that the RLEM approach overestimates failure probability(P_(f))by considering seismic stability with spatial heterogeneity.The P_(f)was observed to increase with an increase in the coefficient of variation of friction angle of the dump materials.Further,it was inferred that the RLEM approach may not be adequately applicable for assessing the seismic stability of an OB dump slope for a horizontal seismic coefficient that is more than or equal to 0.1.展开更多
Based on the theory of Timoshenko and thin-walled beams, a new finite element model of spatial thin-walled beams with general open cross sections is presented in the paper, in which several factors are included such a...Based on the theory of Timoshenko and thin-walled beams, a new finite element model of spatial thin-walled beams with general open cross sections is presented in the paper, in which several factors are included such as lateral shear deformation, warp generated by nonuni- form torsion and second-order shear stress, coupling of flexure and torsion, and large displacement with small strain. With an additional internal node in the element, the element stiffness matrix is deduced by incremental virtual work in updated Lagrangian （UL） formulation. Numerical examples demonstrate that the presented model well describes the geometrically nonlinear property of spatial thin-walled beams.展开更多
A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling fact...A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling factors for elements distribution. The mean grain size exhibits a wide variation ranging from 0.09Φ to 8.05Φ with an average value of 5.33Φ. The average contents of major elements descend in an order of c(SiO_2)>c(Al_2O_3)>c(Fe_2O_3)>c(CaO)>c(MgO)>c(K_2O)>c(Na_2O)>c(TiO_2)>c(P_2O_5)>c(MnO), while those of trace elements exhibit a descending order of c(Sr)>c(Rb)>c(V)>c(Zn)>c(Cr)>c(Pb)>c(Ni)>c(Cu)>c(As). On the basis of elementary distribution characteristics and statistical analyses, the study area is divided into the four zones: Zone I is located in the northeastern coastal area of the gulf, which receives large amount of fluvial materials from local rivers in Guangxi and Guangdong, China, and the Qiongzhou Strait; Zone Ⅱ is located in the center of the study area, where surface sediments exhibits a multiple source; Zone Ⅲ is located in the Qiongzhou Strait, where surface sediments are dominated by materials from the Zhujiang River and Hainan; Zone IV is located in the southwest of the study area, where surface sediments are mainly originated from the Red River and Hainan. The statistical analyses of sediment geochemical characteristics reveal that the grain size, which is mainly influenced by hydrodynamics and mineral composition of terrigenous materials, is the leading factor controlling the elementary distribution.Meanwhile, impacts from anthropogenic activities and marine biogenic process will also be taken into consideration.展开更多
The traditional generalization-based knowledge discovery method is introduced. A new kind of multilevel spatial association of the rules mining method based on the cloud model is presented. The cloud model integrates ...The traditional generalization-based knowledge discovery method is introduced. A new kind of multilevel spatial association of the rules mining method based on the cloud model is presented. The cloud model integrates the vague and random use of linguistic terms in a unified way. With these models, spatial and nonspatial attribute values are well generalized at multiple levels, allowing discovery of strong spatial association rules. Combining the cloud model based method with Apriori algorithms for mining association rules from a spatial database shows benefits in being effective and flexible.展开更多
Association rule mining methods, as a set of important data mining tools, could be used for mining spatial association rules of spatial data. However, applications of these methods are limited for mining results conta...Association rule mining methods, as a set of important data mining tools, could be used for mining spatial association rules of spatial data. However, applications of these methods are limited for mining results containing large number of redundant rules. In this paper, a new method named Geo-Filtered Association Rules Mining(GFARM) is proposed to effectively eliminate the redundant rules. An application of GFARM is performed as a case study in which association rules are discovered between building land distribution and potential driving factors in Wuhan, China from 1995 to 2015. Ten sets of regular sampling grids with different sizes are used for detecting the influence of multi-scales on GFARM. Results show that the proposed method can filter 50%–70% of redundant rules. GFARM is also successful in discovering spatial association pattern between building land distribution and driving factors.展开更多
City cluster is an effective platform for encouraging regionally coordinated development.Coordinated reduction of carbon emissions within city cluster via the spatial association network between cities can help coordi...City cluster is an effective platform for encouraging regionally coordinated development.Coordinated reduction of carbon emissions within city cluster via the spatial association network between cities can help coordinate the regional carbon emission management,realize sustainable development,and assist China in achieving the carbon peaking and carbon neutrality goals.This paper applies the improved gravity model and social network analysis(SNA)to the study of spatial correlation of carbon emissions in city clusters and analyzes the structural characteristics of the spatial correlation network of carbon emissions in the Yangtze River Delta(YRD)city cluster in China and its influencing factors.The results demonstrate that:1)the spatial association of carbon emissions in the YRD city cluster exhibits a typical and complex multi-threaded network structure.The network association number and density show an upward trend,indicating closer spatial association between cities,but their values remain generally low.Meanwhile,the network hierarchy and network efficiency show a downward trend but remain high.2)The spatial association network of carbon emissions in the YRD city cluster shows an obvious‘core-edge’distribution pattern.The network is centered around Shanghai,Suzhou and Wuxi,all of which play the role of‘bridges’,while cities such as Zhoushan,Ma'anshan,Tongling and other cities characterized by the remote location,single transportation mode or lower economic level are positioned at the edge of the network.3)Geographic proximity,varying levels of economic development,different industrial structures,degrees of urbanization,levels of technological innovation,energy intensities and environmental regulation are important influencing factors on the spatial association of within the YRD city cluster.Finally,policy implications are provided from four aspects:government macro-control and market mechanism guidance,structural characteristics of the‘core-edge’network,reconfiguration and optimization of the spatial layout of the YRD city cluster,and the application of advanced technologies.展开更多
Abies georgei var.smithii is an important plant species in Southeast Tibet,China.It has high ecological value in terms of biodiversity protection,as well as soil and water conservation.We analyzed the spatial pattern ...Abies georgei var.smithii is an important plant species in Southeast Tibet,China.It has high ecological value in terms of biodiversity protection,as well as soil and water conservation.We analyzed the spatial pattern and associations of A.georgei var.smithii populations at different growth stages by using Ripley's L function for point pattern analysis.The diameter structure was a nearly reverse 'J' shape.The amount of saplings and medium-sized trees accounts for a large part of the entire population,suggesting a high regeneration rate and an expanding population.In the transition from saplings to medium trees or to large trees,saplings show a significant aggregation distribution at small scales,while medium trees and large trees show a random distribution.There are significant inverse associations between saplings and medium trees and large trees at small scales,while there are no obvious associations between medium trees and large trees.The natural regeneration was affected by interspecific competition,and it was also affected by intraspecific competition.The joint effects of biological characteristics and environmental factors contribute to the spatial distribution pattern and associations of this A.georgei var.sm ithii population.展开更多
Wetland is the conjunction of lake and terrene where human activities are concentrated. From the viewpoints of material transport and cycling in the terrene-lake system, wetland is the buffer where sand and mud, heavy...Wetland is the conjunction of lake and terrene where human activities are concentrated. From the viewpoints of material transport and cycling in the terrene-lake system, wetland is the buffer where sand and mud, heavy metals, pollutants and nutrients are tarried. In this paper, we provide a case study based on the temporal and spatial distribution of elements in the Wangling River catchment, a small sub-catchment of Longgan Lake in the middle reaches of the Yangtze River. We have found that wetland can buffer major heavy metals such as Cr, Cu, etc. significantly, but has a little buffer function to some active elements such as Fe and Mn, which are always transported as solutions. Human activities not only influence the distribution of elements, but also weaken the buffer function of wetland. Intensive human activities in the Longgan Lake area in the past 70 years have been recorded in stream, wetland and lake sediments, especially the human activity events such as deforesting and reclaiming on a large scale in 1958 and the 1980’s. Human activities caused the increase of sedimentation rates since the 1950’s, as well as the increase of elements’ concentrations. The extensive use of fertilizers and pesticides since the 1960’s have led to the increase of total P concentrations. Increasing SO-2 emission accelerate the process of cation exchange in soil, and enhance the leaching of Mn out of soils. Permanent storing of water causes the soil gleyification that also intensifies the leaching of Mn. These are two major reasons for the obvious increase of manganese concentrations in recent 20 years in Longgan Lake. Intensive human activities since the 1950s’ have intensified the population in this region and thus destroyed the buffer function of wetland.展开更多
Hotspots (active fires) indicate spatial distribution of fires. A study on determining influence factors for hotspot occurrence is essential so that fire events can be predicted based on characteristics of a certain a...Hotspots (active fires) indicate spatial distribution of fires. A study on determining influence factors for hotspot occurrence is essential so that fire events can be predicted based on characteristics of a certain area. This study discovers the possible influence factors on the occurrence of fire events using the association rule algorithm namely Apriori in the study area of Rokan Hilir Riau Province Indonesia. The Apriori algorithm was applied on a forest fire dataset which containeddata on physical environment (land cover, river, road and city center), socio-economic (income source, population, and number of school), weather (precipitation, wind speed, and screen temperature), and peatlands. The experiment results revealed 324 multidimensional association rules indicating relationships between hotspots occurrence and other factors.The association among hotspots occurrence with other geographical objects was discovered for the minimum support of 10% and the minimum confidence of 80%. The results show that strong relations between hotspots occurrence and influence factors are found for the support about 12.42%, the confidence of 1, and the lift of 2.26. These factors are precipitation greater than or equal to 3 mm/day, wind speed in [1m/s, 2m/s), non peatland area, screen temperature in [297K, 298K), the number of school in 1 km2 less than or equal to 0.1, and the distance of each hotspot to the nearest road less than or equal to 2.5 km.展开更多
Five trace elements including Zn, Cu, Cd, Cr and As were investigated in surface water from ten typical sampling sites in Honghu Lake. The consequence indicated that all of the detected trace element levels were withi...Five trace elements including Zn, Cu, Cd, Cr and As were investigated in surface water from ten typical sampling sites in Honghu Lake. The consequence indicated that all of the detected trace element levels were within the allowed standard of China’s safe water guideline. The hazard quotients （HQ） and the hazard index （HI） value levels of all the five heavy metals in all sampling sites did not exceed the acceptable risk limits of non-carcinogenic value through the selected assessment method. Pearson’s correlation analysis and principal component analysis （PCA） indicated that Zn and Cu mainly originated from the natural alluviation and non-point agricultural sources, whereas Cr and As were mainly derived from industrial effluents. Moreover, Cd mainly originated from both non-point agricultural and industrial pollution sources. In addition, cluster analysis （CA） implied that cluster 1 （including S3, S5, S6 and S10） was considered the set of high pollution sites and cluster 2 （including S4 and S9） was identified as the set of moderate pollution sites.展开更多
A stabilized finite element algorithm potential for wind-structure interaction(WSI) problem is presented in this paper. Streamline upwind Petrov-Galerkin(SUPG) scheme of the large eddy simulation(LES) of dynamic sub-g...A stabilized finite element algorithm potential for wind-structure interaction(WSI) problem is presented in this paper. Streamline upwind Petrov-Galerkin(SUPG) scheme of the large eddy simulation(LES) of dynamic sub-grid scale(DSGS) is developed under the framework of arbitrary Lagrangian-Eulerian(ALE) description to solve the governing equations. High stabilization is achieved by a three-step technique in the temporal discretization. On the other hand, the partitioned procedure is employed for the consideration of the coupled WSI problem. Newmark integral method is introduced for the computation of structure domain, while spring analogy method is used for the grid update of the mesh domain. The developed computational codes are applied to the analysis of wind-induced effect of a spatial latticed structure. The numerical predictions of the three-dimensional wind flow features, the wind pressures and the wind-induced effect of spatial structures are given. Comparisons are made between the effects of rigid structure in view of the WSI.展开更多
The present study attempted to evaluate the influence of human activity on major elements （Na2O, MgO, A1203, SiO2, K2O, CaO, Fe203）, and to find a method to explore correlations between major elements and human dist...The present study attempted to evaluate the influence of human activity on major elements （Na2O, MgO, A1203, SiO2, K2O, CaO, Fe203）, and to find a method to explore correlations between major elements and human disturbances, according to geospatial theories and methods. The study results indicate that landscapes influence major elements in diverse ways： Al2O3 is closely related to road and mine landscapes; strong relationships exist between MgO, Fe2O3, CaO, and SiO2 and roads; Na2O, SiO2, and Fe2O3 are unrelated to city landscapes; and Na2O is unrelated to road and mine landscapes.展开更多
This paper discusses about the significance of space in the expression of the main themes in Kafka＇s novel The Metamorphosis. By applying Bal＇s basic narratology concepts on space, 2 spatial elements are analyzed in...This paper discusses about the significance of space in the expression of the main themes in Kafka＇s novel The Metamorphosis. By applying Bal＇s basic narratology concepts on space, 2 spatial elements are analyzed in the paper： the contrast of inside and outside, as well as the ＂filling in＂ of space, both of which serve to express human beings＇ isolation and desertion in an indifferent society.展开更多
Along with the rise of buildings, a large number of public open spaces have been created for the purpose of mitigating hatching restrictions and the like. However, many of them are used at low levels, and there remain...Along with the rise of buildings, a large number of public open spaces have been created for the purpose of mitigating hatching restrictions and the like. However, many of them are used at low levels, and there remain very few known public open spaces. In this research, we set up a resting place to demonstrate the effect of elements and placement in order to obtain knowledge for appropriately managing and utilizing such low use open public spaces. The survey means analyzed the presence/absence of the attraction/retention degree based on the cross-sectional traffic volume by video analysis and a hearing questionnaire survey for the users of the resting place. From the results, we have found that placement methods and effects that exceed the expectation value of each element, regionality, and attachment, occur by continuing experiments.展开更多
In data mining from transaction DB, the relationships between the attributes have been focused, but the relationships between the tuples have not been taken into account. In spatial database, there are relationships b...In data mining from transaction DB, the relationships between the attributes have been focused, but the relationships between the tuples have not been taken into account. In spatial database, there are relationships between the attributes and the tuples, and most of the associations occur between the tuples, such as adjacent, intersection, overlap and other topological relationships. So the tasks of spatial data association rules mining include mining the relationships between attributes of spatial objects, which are called as vertical direction DM, and the relationships between the tuples, which are called as horizontal direction DM. This paper analyzes the storage models of spatial data, uses for reference the technologies of data mining in transaction DB, defines the spatial data association rule, including vertical direction association rule, horizontal direction association rule and two-direction association rule, discusses the measurement of spatial association rule interestingness, and puts forward the work flows of spatial association rule data mining. During two-direction spatial association rules mining, an algorithm is proposed to get non-spatial itemsets. By virtue of spatial analysis, the spatial relations were transferred into non-spatial associations and the non-spatial itemsets were gotten. Based on the non-spatial itemsets, the Apriori algorithm or other algorithms could be used to get the frequent itemsets and then the spatial association rules come into being. Using spatial DB, the spatial association rules were gotten to validate the algorithm, and the test results show that this algorithm is efficient and can mine the interesting spatial rules.展开更多
Microwave thermochemotherapy(MTC)has been applied to treat lip squamous cell carcinoma(LSCC),but a deeper understanding of its therapeutic mechanisms and molecular biology is needed.To address this,we used single-cell...Microwave thermochemotherapy(MTC)has been applied to treat lip squamous cell carcinoma(LSCC),but a deeper understanding of its therapeutic mechanisms and molecular biology is needed.To address this,we used single-cell transcriptomics(scRNA-seq)and spatial transcriptomics(ST)to highlight the pivotal role of tumor-associated neutrophils(TANs)among tumor-infiltrating immune cells and their therapeutic response to MTC.MNDA+TANs with anti-tumor activity(N1-phenotype)are found to be abundantly infiltrated by MTC with benefit of increased blood perfusion,and these TANs are characterized by enhanced cytotoxicity,ameliorated hypoxia,and upregulated IL1B,activating T&NK cells and fibroblasts via IL1B-IL1R.In this highly anti-tumor immunogenic and hypoxia-reversed microenvironment under MTC,fibroblasts accumulated in the tumor front(TF)can recruit N1-TANs via CXCL2-CXCR2 and clear N2-TANs(pro-tumor phenotype)via CXCL12-CXCR4,which results in the aggregation of N1-TANs and extracellular matrix(ECM)deposition.In addition,we construct an N1-TANs marker,MX2,which positively correlates with better prognosis in LSCC patients,and employ deep learning techniques to predict expression of MX2 from hematoxylin-eosin(H&E)-stained images so as to conveniently guide decision making in clinical practice.Collectively,our findings demonstrate that the N1-TANs/fibroblasts defense wall formed in response to MTC effectively combat LSCC.展开更多
In response to concerns over the recent expansion of the scope and content of urban design and the potential for“loss of focus”,this study uses the comprehensive urban design of Pudong New Area as a case study,empha...In response to concerns over the recent expansion of the scope and content of urban design and the potential for“loss of focus”,this study uses the comprehensive urban design of Pudong New Area as a case study,emphasizing a need to“refocus”urban design efforts.It traces the spatial evolution of Pudong New Area under national strategic guidance,addressing two primary issues from a“strategy-problem”perspective.Building on the link between municipal urban design and district-level master planning,the study proposes a key element system that integrates“significance,publicness,cultural relevance,and connectivity”and a control strategy based on unit typology and policy-guided zoning.By establishing a clear and concise district-level control framework focused on“element+scale”,the study aims to enhance Pudong’s modern spatial image and its holistic spatial order,reinforcing Pudong’s role as a“leading area for socialist modernization”.展开更多
The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,partic...The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,particularly those evaluating multiple metals across several snowpits,making interpretation challenging.This study investigates the distributions and sources of trace elements-including Cd,Ba,Pb,U,Bi,V,Mn,Fe,Cu,Zn,and As-across four snowpits in the Lambert Glacier Basin,East Antarctica.The trace elements exhibit site-,element-,and season-dependent variations,with higher concentrations observed at inland sites.In contrast,δ^(18)O and ion concentrations decrease with increasing distance from the coast and elevation,underscoring the influence of marine emissions.Crustal sources primarily contributed to Ba,U,V,Mn,and Fe,while non-crustal sources predominantly contributed to Cd,Bi,Zn,Pb,Cu,and As.Positive matrix factorization(PMF)analysis indicates that trace element concentrations in Pits 2 and 3 are influenced by both crustal and non-crustal sources,while Pit 4 reflects a mixed-source influence.Pit 1(coastal site)also indicates the mixed sources with influence of a highly dynamic marine climate and environment.The PMF results reveal similarities in emission sources and atmospheric transport patterns across the snowpits,facilitating a more comprehensive interpretation of longer ice core records.Overall,this study provides valuable insights into trace element distributions and enhances our understanding of past environmental and climatic conditions.展开更多
The incorporation of graphene fillers into polymer matrices has been recognized for its potential to enhance thermal conductivity,which is particularly beneficial for applications in thermal management.The uniformity ...The incorporation of graphene fillers into polymer matrices has been recognized for its potential to enhance thermal conductivity,which is particularly beneficial for applications in thermal management.The uniformity of graphene dispersion is pivotal to achieving optimal thermal conductivity,thereby directly influencing the effectiveness of thermal management,including the mitigation of local hot-spot temperatures.This research employs a quantitative approach to assess the distribution of graphene fillers within a PBX(plastic-bonded explosive)matrix,focusing specifically on the thermal management of hot spots.Through finite element method(FEM)simulations,we have explored the impact of graphene filler orientation,proximity to the central heat source,and spatial clustering on heat transfer.Our findings indicate that the strategic distribution of graphene fillers can create efficient thermal conduction channels,which significantly reduce the temperatures at local hot spots.In a model containing 0.336%graphene by volume,the central hot-spot temperature was reduced by approximately 60 K compared to a pure PBX material,under a heat flux of 600 W/m^(2).This study offers valuable insights into the optimization of the spatial arrangement of low-concentration graphene fillers,aiming to improve the thermal management capabilities of HMX-based PBX explosives.展开更多
【目的】当前在微地图的内容检索领域尚缺乏系统性的研究。为了填补这一研究空白,本文提出了一种YOLOv8l-FMSC-Spatial (You Only Look Once v8l-Fewer Multi-Scale Convolution-Spatial, YOLOv8l-FMSC-Spatial)模型,实现在手绘地图场...【目的】当前在微地图的内容检索领域尚缺乏系统性的研究。为了填补这一研究空白,本文提出了一种YOLOv8l-FMSC-Spatial (You Only Look Once v8l-Fewer Multi-Scale Convolution-Spatial, YOLOv8l-FMSC-Spatial)模型,实现在手绘地图场景下地理要素的提取及检索。【方法】首先通过对比YOLO系列模型,选取最优的YOLOv8l模型,引入C2f-FMSC模块改进最优模型,建立应用于微地图的YOLOv8l-FMSC训练模型,利用该模型实现栅格地图的地理要素提取;其次针对地理要素的检索需要,建立地理要素的空间关系数据库,设计空间计算检索模块Spatial,通过Spatial模块实现地理要素信息的传递与筛选,进一步地计算用户检索信息与数据库地理要素信息的空间关系关联程度;最后根据空间关系关联程度,从微地图数据库中索引包含相关地理要素信息的地图,实现基于空间关系的地理要素检索模型构建。依据上述方法,在手绘校园地图检索场景中进行验证。实验数据源自各个学校发布内容以及学生自由制作,共计493幅手绘校园地图,在全国范围内研究学校代表性地理要素检索,此类要素包括水体、操场、特色建筑,确保准确识别和检索这些特征元素,验证所提模型的实际适用性。【结果】实验结果表明:训练后的YOLOv8l模型可有效识别手绘地图中的地理要素,并在收集的数据集上验证了模型的有效性和鲁棒性;引入FMSC模块后的YOLOv8l-FMSC模型精确率可达0.8、召回率可达0.764,为实际对比中的最优模型;引入Spatial模块计算模型度量空间关系,可有效捕捉到相关地理要素的空间信息,减少与正射地图检索的差距。【结论】综上,提出的YOLOv8l-FMSC-Spatial模型可根据顾及空间关系的地理要素条件,快速准确地检索到内容相关的手绘地图,从而填补微地图在内容检索方面的研究空缺。展开更多
基金the financial support provided by MHRD,Govt.of IndiaCoal India Limited for providing financial assistance for the research(Project No.CIL/R&D/01/73/2021)the partial financial support provided by the Ministry of Education,Government of India,under SPARC project(Project No.P1207)。
文摘Sudden and unforeseen seismic failures of coal mine overburden(OB)dump slopes interrupt mining operations,cause loss of lives and delay the production of coal.Consideration of the spatial heterogeneity of OB dump materials is imperative for an adequate evaluation of the seismic stability of OB dump slopes.In this study,pseudo-static seismic stability analyses are carried out for an OB dump slope by considering the material parameters obtained from an insitu field investigation.Spatial heterogeneity is simulated through use of the random finite element method(RFEM)and the random limit equilibrium method(RLEM)and a comparative study is presented.Combinations of horizontal and vertical spatial correlation lengths were considered for simulating isotropic and anisotropic random fields within the OB dump slope.Seismic performances of the slope have been reported through the probability of failure and reliability index.It was observed that the RLEM approach overestimates failure probability(P_(f))by considering seismic stability with spatial heterogeneity.The P_(f)was observed to increase with an increase in the coefficient of variation of friction angle of the dump materials.Further,it was inferred that the RLEM approach may not be adequately applicable for assessing the seismic stability of an OB dump slope for a horizontal seismic coefficient that is more than or equal to 0.1.
基金supported by the National Science Fund for Distinguished Young Scholars (No. 50725826).
文摘Based on the theory of Timoshenko and thin-walled beams, a new finite element model of spatial thin-walled beams with general open cross sections is presented in the paper, in which several factors are included such as lateral shear deformation, warp generated by nonuni- form torsion and second-order shear stress, coupling of flexure and torsion, and large displacement with small strain. With an additional internal node in the element, the element stiffness matrix is deduced by incremental virtual work in updated Lagrangian （UL） formulation. Numerical examples demonstrate that the presented model well describes the geometrically nonlinear property of spatial thin-walled beams.
基金The National Programme on Global Change and Air-Sea Interaction of China under contract Nos GASI-GEOGE-03,GASI-04-01-02 and GASI-GEOGE-05the National Natural Science Foundation of China under contract Nos 41476047,41106045,41506012 and 41206045
文摘A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling factors for elements distribution. The mean grain size exhibits a wide variation ranging from 0.09Φ to 8.05Φ with an average value of 5.33Φ. The average contents of major elements descend in an order of c(SiO_2)>c(Al_2O_3)>c(Fe_2O_3)>c(CaO)>c(MgO)>c(K_2O)>c(Na_2O)>c(TiO_2)>c(P_2O_5)>c(MnO), while those of trace elements exhibit a descending order of c(Sr)>c(Rb)>c(V)>c(Zn)>c(Cr)>c(Pb)>c(Ni)>c(Cu)>c(As). On the basis of elementary distribution characteristics and statistical analyses, the study area is divided into the four zones: Zone I is located in the northeastern coastal area of the gulf, which receives large amount of fluvial materials from local rivers in Guangxi and Guangdong, China, and the Qiongzhou Strait; Zone Ⅱ is located in the center of the study area, where surface sediments exhibits a multiple source; Zone Ⅲ is located in the Qiongzhou Strait, where surface sediments are dominated by materials from the Zhujiang River and Hainan; Zone IV is located in the southwest of the study area, where surface sediments are mainly originated from the Red River and Hainan. The statistical analyses of sediment geochemical characteristics reveal that the grain size, which is mainly influenced by hydrodynamics and mineral composition of terrigenous materials, is the leading factor controlling the elementary distribution.Meanwhile, impacts from anthropogenic activities and marine biogenic process will also be taken into consideration.
文摘The traditional generalization-based knowledge discovery method is introduced. A new kind of multilevel spatial association of the rules mining method based on the cloud model is presented. The cloud model integrates the vague and random use of linguistic terms in a unified way. With these models, spatial and nonspatial attribute values are well generalized at multiple levels, allowing discovery of strong spatial association rules. Combining the cloud model based method with Apriori algorithms for mining association rules from a spatial database shows benefits in being effective and flexible.
基金Under the auspices of Special Fund of Ministry of Land and Resources of China in Public Interest(No.201511001)
文摘Association rule mining methods, as a set of important data mining tools, could be used for mining spatial association rules of spatial data. However, applications of these methods are limited for mining results containing large number of redundant rules. In this paper, a new method named Geo-Filtered Association Rules Mining(GFARM) is proposed to effectively eliminate the redundant rules. An application of GFARM is performed as a case study in which association rules are discovered between building land distribution and potential driving factors in Wuhan, China from 1995 to 2015. Ten sets of regular sampling grids with different sizes are used for detecting the influence of multi-scales on GFARM. Results show that the proposed method can filter 50%–70% of redundant rules. GFARM is also successful in discovering spatial association pattern between building land distribution and driving factors.
基金Under the auspices of the National Natural Science Foundation of China (No.72273151)。
文摘City cluster is an effective platform for encouraging regionally coordinated development.Coordinated reduction of carbon emissions within city cluster via the spatial association network between cities can help coordinate the regional carbon emission management,realize sustainable development,and assist China in achieving the carbon peaking and carbon neutrality goals.This paper applies the improved gravity model and social network analysis(SNA)to the study of spatial correlation of carbon emissions in city clusters and analyzes the structural characteristics of the spatial correlation network of carbon emissions in the Yangtze River Delta(YRD)city cluster in China and its influencing factors.The results demonstrate that:1)the spatial association of carbon emissions in the YRD city cluster exhibits a typical and complex multi-threaded network structure.The network association number and density show an upward trend,indicating closer spatial association between cities,but their values remain generally low.Meanwhile,the network hierarchy and network efficiency show a downward trend but remain high.2)The spatial association network of carbon emissions in the YRD city cluster shows an obvious‘core-edge’distribution pattern.The network is centered around Shanghai,Suzhou and Wuxi,all of which play the role of‘bridges’,while cities such as Zhoushan,Ma'anshan,Tongling and other cities characterized by the remote location,single transportation mode or lower economic level are positioned at the edge of the network.3)Geographic proximity,varying levels of economic development,different industrial structures,degrees of urbanization,levels of technological innovation,energy intensities and environmental regulation are important influencing factors on the spatial association of within the YRD city cluster.Finally,policy implications are provided from four aspects:government macro-control and market mechanism guidance,structural characteristics of the‘core-edge’network,reconfiguration and optimization of the spatial layout of the YRD city cluster,and the application of advanced technologies.
基金funded by the National Key Technology Support Program (2013BAC04B01)
文摘Abies georgei var.smithii is an important plant species in Southeast Tibet,China.It has high ecological value in terms of biodiversity protection,as well as soil and water conservation.We analyzed the spatial pattern and associations of A.georgei var.smithii populations at different growth stages by using Ripley's L function for point pattern analysis.The diameter structure was a nearly reverse 'J' shape.The amount of saplings and medium-sized trees accounts for a large part of the entire population,suggesting a high regeneration rate and an expanding population.In the transition from saplings to medium trees or to large trees,saplings show a significant aggregation distribution at small scales,while medium trees and large trees show a random distribution.There are significant inverse associations between saplings and medium trees and large trees at small scales,while there are no obvious associations between medium trees and large trees.The natural regeneration was affected by interspecific competition,and it was also affected by intraspecific competition.The joint effects of biological characteristics and environmental factors contribute to the spatial distribution pattern and associations of this A.georgei var.sm ithii population.
文摘Wetland is the conjunction of lake and terrene where human activities are concentrated. From the viewpoints of material transport and cycling in the terrene-lake system, wetland is the buffer where sand and mud, heavy metals, pollutants and nutrients are tarried. In this paper, we provide a case study based on the temporal and spatial distribution of elements in the Wangling River catchment, a small sub-catchment of Longgan Lake in the middle reaches of the Yangtze River. We have found that wetland can buffer major heavy metals such as Cr, Cu, etc. significantly, but has a little buffer function to some active elements such as Fe and Mn, which are always transported as solutions. Human activities not only influence the distribution of elements, but also weaken the buffer function of wetland. Intensive human activities in the Longgan Lake area in the past 70 years have been recorded in stream, wetland and lake sediments, especially the human activity events such as deforesting and reclaiming on a large scale in 1958 and the 1980’s. Human activities caused the increase of sedimentation rates since the 1950’s, as well as the increase of elements’ concentrations. The extensive use of fertilizers and pesticides since the 1960’s have led to the increase of total P concentrations. Increasing SO-2 emission accelerate the process of cation exchange in soil, and enhance the leaching of Mn out of soils. Permanent storing of water causes the soil gleyification that also intensifies the leaching of Mn. These are two major reasons for the obvious increase of manganese concentrations in recent 20 years in Longgan Lake. Intensive human activities since the 1950s’ have intensified the population in this region and thus destroyed the buffer function of wetland.
文摘Hotspots (active fires) indicate spatial distribution of fires. A study on determining influence factors for hotspot occurrence is essential so that fire events can be predicted based on characteristics of a certain area. This study discovers the possible influence factors on the occurrence of fire events using the association rule algorithm namely Apriori in the study area of Rokan Hilir Riau Province Indonesia. The Apriori algorithm was applied on a forest fire dataset which containeddata on physical environment (land cover, river, road and city center), socio-economic (income source, population, and number of school), weather (precipitation, wind speed, and screen temperature), and peatlands. The experiment results revealed 324 multidimensional association rules indicating relationships between hotspots occurrence and other factors.The association among hotspots occurrence with other geographical objects was discovered for the minimum support of 10% and the minimum confidence of 80%. The results show that strong relations between hotspots occurrence and influence factors are found for the support about 12.42%, the confidence of 1, and the lift of 2.26. These factors are precipitation greater than or equal to 3 mm/day, wind speed in [1m/s, 2m/s), non peatland area, screen temperature in [297K, 298K), the number of school in 1 km2 less than or equal to 0.1, and the distance of each hotspot to the nearest road less than or equal to 2.5 km.
基金Projects(51578222,51178172) supported by the National Natural Science Foundation of ChinaProjects(17Z017,17G025) supported by the Humanities and Social Science Project of Hubei Provincial Education Department,China+1 种基金Project(1718WT15) supported by the Hubei College Student Affairs Research Institute,ChinaProjects(2016J1410,2016J1411) supported by the Graduate Innovative Education Program of Zhongnan University of Economics and Law,China
文摘Five trace elements including Zn, Cu, Cd, Cr and As were investigated in surface water from ten typical sampling sites in Honghu Lake. The consequence indicated that all of the detected trace element levels were within the allowed standard of China’s safe water guideline. The hazard quotients （HQ） and the hazard index （HI） value levels of all the five heavy metals in all sampling sites did not exceed the acceptable risk limits of non-carcinogenic value through the selected assessment method. Pearson’s correlation analysis and principal component analysis （PCA） indicated that Zn and Cu mainly originated from the natural alluviation and non-point agricultural sources, whereas Cr and As were mainly derived from industrial effluents. Moreover, Cd mainly originated from both non-point agricultural and industrial pollution sources. In addition, cluster analysis （CA） implied that cluster 1 （including S3, S5, S6 and S10） was considered the set of high pollution sites and cluster 2 （including S4 and S9） was identified as the set of moderate pollution sites.
基金the National Natural Science Foundation of China(Nos.11172174 and 51278297)the Research Program of Shanghai Leader Talent(No.20)the Doctoral Disciplinary Special Research Project of Chinese Ministry of Education(No.20130073110096)
文摘A stabilized finite element algorithm potential for wind-structure interaction(WSI) problem is presented in this paper. Streamline upwind Petrov-Galerkin(SUPG) scheme of the large eddy simulation(LES) of dynamic sub-grid scale(DSGS) is developed under the framework of arbitrary Lagrangian-Eulerian(ALE) description to solve the governing equations. High stabilization is achieved by a three-step technique in the temporal discretization. On the other hand, the partitioned procedure is employed for the consideration of the coupled WSI problem. Newmark integral method is introduced for the computation of structure domain, while spring analogy method is used for the grid update of the mesh domain. The developed computational codes are applied to the analysis of wind-induced effect of a spatial latticed structure. The numerical predictions of the three-dimensional wind flow features, the wind pressures and the wind-induced effect of spatial structures are given. Comparisons are made between the effects of rigid structure in view of the WSI.
基金supported by the Youth Science Foundation (Grant Nos. 41101174 and 41301094)the Lead Strategic Project of the Chinese Academy of Sciences (Grant No. XDB03030507)+1 种基金the Hundred Young Talents Program of the Institute of Mountain Hazards and Environment (Grant No. SDSQB-2015-02)the Open Fund for Key Laboratory of Geoscience Spatial Information Technology of Ministry of Land and Resources (Grant No. KLGSIT2016-01)
文摘The present study attempted to evaluate the influence of human activity on major elements （Na2O, MgO, A1203, SiO2, K2O, CaO, Fe203）, and to find a method to explore correlations between major elements and human disturbances, according to geospatial theories and methods. The study results indicate that landscapes influence major elements in diverse ways： Al2O3 is closely related to road and mine landscapes; strong relationships exist between MgO, Fe2O3, CaO, and SiO2 and roads; Na2O, SiO2, and Fe2O3 are unrelated to city landscapes; and Na2O is unrelated to road and mine landscapes.
文摘This paper discusses about the significance of space in the expression of the main themes in Kafka＇s novel The Metamorphosis. By applying Bal＇s basic narratology concepts on space, 2 spatial elements are analyzed in the paper： the contrast of inside and outside, as well as the ＂filling in＂ of space, both of which serve to express human beings＇ isolation and desertion in an indifferent society.
文摘Along with the rise of buildings, a large number of public open spaces have been created for the purpose of mitigating hatching restrictions and the like. However, many of them are used at low levels, and there remain very few known public open spaces. In this research, we set up a resting place to demonstrate the effect of elements and placement in order to obtain knowledge for appropriately managing and utilizing such low use open public spaces. The survey means analyzed the presence/absence of the attraction/retention degree based on the cross-sectional traffic volume by video analysis and a hearing questionnaire survey for the users of the resting place. From the results, we have found that placement methods and effects that exceed the expectation value of each element, regionality, and attachment, occur by continuing experiments.
基金The work is supported by Natural Science Foundatiion of Chongqing (No .CSTC 2005BB2065)
文摘In data mining from transaction DB, the relationships between the attributes have been focused, but the relationships between the tuples have not been taken into account. In spatial database, there are relationships between the attributes and the tuples, and most of the associations occur between the tuples, such as adjacent, intersection, overlap and other topological relationships. So the tasks of spatial data association rules mining include mining the relationships between attributes of spatial objects, which are called as vertical direction DM, and the relationships between the tuples, which are called as horizontal direction DM. This paper analyzes the storage models of spatial data, uses for reference the technologies of data mining in transaction DB, defines the spatial data association rule, including vertical direction association rule, horizontal direction association rule and two-direction association rule, discusses the measurement of spatial association rule interestingness, and puts forward the work flows of spatial association rule data mining. During two-direction spatial association rules mining, an algorithm is proposed to get non-spatial itemsets. By virtue of spatial analysis, the spatial relations were transferred into non-spatial associations and the non-spatial itemsets were gotten. Based on the non-spatial itemsets, the Apriori algorithm or other algorithms could be used to get the frequent itemsets and then the spatial association rules come into being. Using spatial DB, the spatial association rules were gotten to validate the algorithm, and the test results show that this algorithm is efficient and can mine the interesting spatial rules.
基金supported by National Natural Science Foundation of China grants(Nos.82173326 and 82473058)Key Research and Development Project of Sichuan Province(Nos.2024YFFK0374 and 2024YFFK0198)Interdisciplinary Innovation Project of West China College of Stomatology,Sichuan University(RD-03-202004).
文摘Microwave thermochemotherapy(MTC)has been applied to treat lip squamous cell carcinoma(LSCC),but a deeper understanding of its therapeutic mechanisms and molecular biology is needed.To address this,we used single-cell transcriptomics(scRNA-seq)and spatial transcriptomics(ST)to highlight the pivotal role of tumor-associated neutrophils(TANs)among tumor-infiltrating immune cells and their therapeutic response to MTC.MNDA+TANs with anti-tumor activity(N1-phenotype)are found to be abundantly infiltrated by MTC with benefit of increased blood perfusion,and these TANs are characterized by enhanced cytotoxicity,ameliorated hypoxia,and upregulated IL1B,activating T&NK cells and fibroblasts via IL1B-IL1R.In this highly anti-tumor immunogenic and hypoxia-reversed microenvironment under MTC,fibroblasts accumulated in the tumor front(TF)can recruit N1-TANs via CXCL2-CXCR2 and clear N2-TANs(pro-tumor phenotype)via CXCL12-CXCR4,which results in the aggregation of N1-TANs and extracellular matrix(ECM)deposition.In addition,we construct an N1-TANs marker,MX2,which positively correlates with better prognosis in LSCC patients,and employ deep learning techniques to predict expression of MX2 from hematoxylin-eosin(H&E)-stained images so as to conveniently guide decision making in clinical practice.Collectively,our findings demonstrate that the N1-TANs/fibroblasts defense wall formed in response to MTC effectively combat LSCC.
基金Sponsored by National Key R&D Projects in the“14th Five-year Plan”(2022YFC3800205)Shanghai Philosophy and Social Sciences Planning Project(2024VSJ034).
文摘In response to concerns over the recent expansion of the scope and content of urban design and the potential for“loss of focus”,this study uses the comprehensive urban design of Pudong New Area as a case study,emphasizing a need to“refocus”urban design efforts.It traces the spatial evolution of Pudong New Area under national strategic guidance,addressing two primary issues from a“strategy-problem”perspective.Building on the link between municipal urban design and district-level master planning,the study proposes a key element system that integrates“significance,publicness,cultural relevance,and connectivity”and a control strategy based on unit typology and policy-guided zoning.By establishing a clear and concise district-level control framework focused on“element+scale”,the study aims to enhance Pudong’s modern spatial image and its holistic spatial order,reinforcing Pudong’s role as a“leading area for socialist modernization”.
基金supported by the Korea Polar Research Institute grant(PE25100)the National Research Foundation of Korea grant funded by the Korean Government(NRF2022R1A2C3007047)supported by Korea Institute of Marine Science&Technology Promotion(KIMST)and by the Ministry of Oceans and Fisheries(RS-2023-00256677,PM23020).
文摘The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,particularly those evaluating multiple metals across several snowpits,making interpretation challenging.This study investigates the distributions and sources of trace elements-including Cd,Ba,Pb,U,Bi,V,Mn,Fe,Cu,Zn,and As-across four snowpits in the Lambert Glacier Basin,East Antarctica.The trace elements exhibit site-,element-,and season-dependent variations,with higher concentrations observed at inland sites.In contrast,δ^(18)O and ion concentrations decrease with increasing distance from the coast and elevation,underscoring the influence of marine emissions.Crustal sources primarily contributed to Ba,U,V,Mn,and Fe,while non-crustal sources predominantly contributed to Cd,Bi,Zn,Pb,Cu,and As.Positive matrix factorization(PMF)analysis indicates that trace element concentrations in Pits 2 and 3 are influenced by both crustal and non-crustal sources,while Pit 4 reflects a mixed-source influence.Pit 1(coastal site)also indicates the mixed sources with influence of a highly dynamic marine climate and environment.The PMF results reveal similarities in emission sources and atmospheric transport patterns across the snowpits,facilitating a more comprehensive interpretation of longer ice core records.Overall,this study provides valuable insights into trace element distributions and enhances our understanding of past environmental and climatic conditions.
基金supported by the National Natural Science Foundation of China(Grant No.U2330208).
文摘The incorporation of graphene fillers into polymer matrices has been recognized for its potential to enhance thermal conductivity,which is particularly beneficial for applications in thermal management.The uniformity of graphene dispersion is pivotal to achieving optimal thermal conductivity,thereby directly influencing the effectiveness of thermal management,including the mitigation of local hot-spot temperatures.This research employs a quantitative approach to assess the distribution of graphene fillers within a PBX(plastic-bonded explosive)matrix,focusing specifically on the thermal management of hot spots.Through finite element method(FEM)simulations,we have explored the impact of graphene filler orientation,proximity to the central heat source,and spatial clustering on heat transfer.Our findings indicate that the strategic distribution of graphene fillers can create efficient thermal conduction channels,which significantly reduce the temperatures at local hot spots.In a model containing 0.336%graphene by volume,the central hot-spot temperature was reduced by approximately 60 K compared to a pure PBX material,under a heat flux of 600 W/m^(2).This study offers valuable insights into the optimization of the spatial arrangement of low-concentration graphene fillers,aiming to improve the thermal management capabilities of HMX-based PBX explosives.
文摘【目的】当前在微地图的内容检索领域尚缺乏系统性的研究。为了填补这一研究空白,本文提出了一种YOLOv8l-FMSC-Spatial (You Only Look Once v8l-Fewer Multi-Scale Convolution-Spatial, YOLOv8l-FMSC-Spatial)模型,实现在手绘地图场景下地理要素的提取及检索。【方法】首先通过对比YOLO系列模型,选取最优的YOLOv8l模型,引入C2f-FMSC模块改进最优模型,建立应用于微地图的YOLOv8l-FMSC训练模型,利用该模型实现栅格地图的地理要素提取;其次针对地理要素的检索需要,建立地理要素的空间关系数据库,设计空间计算检索模块Spatial,通过Spatial模块实现地理要素信息的传递与筛选,进一步地计算用户检索信息与数据库地理要素信息的空间关系关联程度;最后根据空间关系关联程度,从微地图数据库中索引包含相关地理要素信息的地图,实现基于空间关系的地理要素检索模型构建。依据上述方法,在手绘校园地图检索场景中进行验证。实验数据源自各个学校发布内容以及学生自由制作,共计493幅手绘校园地图,在全国范围内研究学校代表性地理要素检索,此类要素包括水体、操场、特色建筑,确保准确识别和检索这些特征元素,验证所提模型的实际适用性。【结果】实验结果表明:训练后的YOLOv8l模型可有效识别手绘地图中的地理要素,并在收集的数据集上验证了模型的有效性和鲁棒性;引入FMSC模块后的YOLOv8l-FMSC模型精确率可达0.8、召回率可达0.764,为实际对比中的最优模型;引入Spatial模块计算模型度量空间关系,可有效捕捉到相关地理要素的空间信息,减少与正射地图检索的差距。【结论】综上,提出的YOLOv8l-FMSC-Spatial模型可根据顾及空间关系的地理要素条件,快速准确地检索到内容相关的手绘地图,从而填补微地图在内容检索方面的研究空缺。
