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Estimation of spatially distributed processes using mobile sensor networks with missing measurements 认领 引用 被引量：3
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作者 江正仙 崔宝同 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期109-115,共7页
This paper investigates the estimation problem for a spatially distributed process described by a partial differential equation with missing measurements.The randomly missing measurements are introduced in order to be... This paper investigates the estimation problem for a spatially distributed process described by a partial differential equation with missing measurements.The randomly missing measurements are introduced in order to better reflect the reality in the sensor network.To improve the estimation performance for the spatially distributed process,a network of sensors which are allowed to move within the spatial domain is used.We aim to design an estimator which is used to approximate the distributed process and the mobile trajectories for sensors such that,for all possible missing measurements,the estimation error system is globally asymptotically stable in the mean square sense.By constructing Lyapunov functionals and using inequality analysis,the guidance scheme of every sensor and the convergence of the estimation error system are obtained.Finally,a numerical example is given to verify the effectiveness of the proposed estimator utilizing the proposed guidance scheme for sensors. 展开更多
关键词 estimation spatially distributed process mobile sensor network missing measurements
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A Time/Space Separation Based 3D Fuzzy Modeling Approach for Nonlinear Spatially Distributed Systems 认领 引用 被引量：1
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作者 Xian-Xia Zhang Zhi-Qiang Fu +2 位作者 Shao-Yuan Li Tao Zou Bing Wang 《International Journal of Automation and computing》 CSCD 2018年第1期52-65,共14页
Spatially distributed systems （SDSs） are usually infinite-dimensional spatio-temporal systems with unknown nonlinearities. Therefore, to model such systems is difficult. In real applications, a low-dimensional model... Spatially distributed systems （SDSs） are usually infinite-dimensional spatio-temporal systems with unknown nonlinearities. Therefore, to model such systems is difficult. In real applications, a low-dimensional model is required. In this paper, a time/space separation based 3D fuzzy modeling approach is proposed for unknown nonlinear SDSs using input-output data measurement. The main characteristics of this approach is that time/space separation and time/space reconstruction are fused into a novel 3D fuzzy system. The modeling methodology includes two stages. The first stage is 3D fuzzy structure modeling which is based on Mamdani fuzzy rules. The consequent sets of 3D fuzzy rules consist of spatial basis functions estimated by Karhunen-Love decomposition. The antecedent sets of 3D fuzzy rules are used to construct temporal coefficients. Going through 3D fuzzy rule inference, each rule realizes time/space synthesis. The second stage is parameter identification of 3D fuzzy system using particle swarm optimization algorithm. After an operation of defuzzification, the output of the 3D fuzzy system can reconstruct the spatio-temporal dynamics of the system. The model is suitable for the prediction and control design of the SDS since it is of low-dimension and simple nonlinear structure. The simulation and experiment are presented to show the effectiveness of the proposed modeling approach. 展开更多
关键词 Spatially distributed system （SDS） system identification 3D fuzzy system Karhunen-Love decomposition particleswarm optimization （PSO）.
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A Nationwide Analysis of Key Environmental Determinants Shaping the Spatial Distribution of Kashin-Beck Disease in China 认领 引用
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作者 Fang Qi Ying Liu +9 位作者 Bing Zhang Qian Yu Songyao Zhang Haoyu Du Jiaxin Li Yue Zhao Chenxi Wang Jiayuan Li Silu Cui Jun Yu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2026年第5期609-615,共7页
Kashin-Beck disease(KBD)is an endemic,deformative osteoarthropathy characterized by distinct geographic clusters[1].Historically,13 provinces and autonomous regions in China have been designated as KBD-affected areas.... Kashin-Beck disease(KBD)is an endemic,deformative osteoarthropathy characterized by distinct geographic clusters[1].Historically,13 provinces and autonomous regions in China have been designated as KBD-affected areas.In severely endemic areas,the radiographic detection rate had reached up to 80%[1].Although comprehensive prevention and control measures,including dietary restructuring,grain substitution,and relocation of educational facilities,have successfully halted new pediatric cases,the persistent threat posed by environmental risk factors suggests that the relaxation of these measures could lead to the resurgence of KBD. 展开更多
关键词 relocation educational facilitieshave radiographic detection dietary restructuringgrain Kashin Beck disease prevention control measuresincluding environmental determinants China spatial distribution
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Heavier sediment pollution by per-and polyfluoroalkyl substances(PFASs)in tropical coasts compared to temperate regions:An overlooked hotspot 认领 引用
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作者 Hui Xie Shiya Gu +3 位作者 Yang Cui Jianwei Dong Hongbing Wang Guowei Fu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2026年第4期456-464,共9页
Tropical coastal environments experience higher precipitation,more intense solar radiation,and elevated sea surface temperature compared to temperate regions.These environmental differences influence the behaviors and... Tropical coastal environments experience higher precipitation,more intense solar radiation,and elevated sea surface temperature compared to temperate regions.These environmental differences influence the behaviors and fate of per-and polyfluoroalkyl substances(PFASs),yet there is a critical gap in understanding the status of both legacy and emerging PFASs in tropical coastal sediments.This study provides a detailed analysis of the distribution,sources,and fate of legacy-,precursor,and emerging PFASs in coastal sediments around a tropical city.PFAS concentrations ranged from 1.33 to 12.6 ng/g,with five legacy PFASs(i.e.,perfluorononanoic acid(PFNA),perfluoroundecanoic acid(PFUnDA),perfluorobutane sulfonate(PFBS),perfluorohexane sulfonate(PFHxS),and perfluooctane sulfonate(PFOS)),and three precursors(i.e.,7H-perfluoroheptanoic acid(7H-PFHpA),8H-perfluorooctanoic acid(8H-PFOA),and 9H-PFNA)consistently detected across all samples.Emerging alternatives,such as 6:2 chlorinated perfluoroether sulfonic acid,were also observed with detection frequencies of 20.0%.Overall,PFAS concentrations in tropical coastal sediments obtained in this study were found to be higher than those reported in temperate regions.The identified main sources of PFASs include landbased inputs such as rainfall-runoff(46.6%),emission from space launch base and dock activities(15.9%),sediment resuspension-deposition(12.6%),and atmospheric deposition(9.65%).Additionally,certain sediment quality parameters acted as indicators for PFAS pollution.Total nitrogen and total phosphorus in sediments were potential indicators for those PFASs with sulfonyl groups,whereas sediment composition was strongly associated with monohydrogen-substituted perfluoroalkyl carboxylic acids and fluorotelomer(unsaturated)carboxylates.These findings provide new insights into the fate of PFASs in coastal environments and highlight the need for further research on their environmental impact. 展开更多
关键词 Coastal sediment Emerging contaminants Per-and polyfluoroalkyl substances(PFASs) Spatial distribution Tropical region
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Spatiotemporal patterns and driving forces of dust weather events in Central Asia from 2000 to 2020 认领 引用
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作者 LIU Yuhan ZHAO Yuanyuan +2 位作者 GAO Guanglei DING Guodong LI Ning 《Journal of Arid Land》 SCIE CAS CSCD 2026年第1期1-16,共16页
Central Asia is characterized by an arid climate and widespread desert distribution,with its sustainable development severely constrained by dust events.An objective understanding of the spatiotemporal patterns and dr... Central Asia is characterized by an arid climate and widespread desert distribution,with its sustainable development severely constrained by dust events.An objective understanding of the spatiotemporal patterns and driving forces of dust weather is highly important in this area.Based on the meteorological observations from 2000 to 2020,we examined the spatiotemporal characteristics of dust weather in the five Central Asian countries(Kazakhstan,Uzbekistan,Kyrgyzstan,Turkmenistan,and Tajikistan)via Theil-Sen trend analysis and Geodetector modeling method,quantitatively revealing the influence of environmental factors,such as temperature,precipitation,and vegetation,on the frequency of dust weather.The results showed that:(1)dust weather in Central Asia was mainly distributed in a large''dust belt''extending from west to east from northern part of the Caspian lowland desert,and concentrated in basins,plains,and other low-altitude areas.Strong dust weather mainly occurred in northern areas of the Aral Sea and southern edge of Central Asia,with a maximum annual frequency of 21.9%;(2)strong dust weather in Central Asia has fluctuated and slightly decreased since 2001.The highest frequency(1.1%)occurred in spring(from March to June);(3)from 2000 to 2020,changes such as spot shifting and shrinking occurred in the four main source areas(north of the Aral Sea,Kyzylkum Desert,Karakum Desert,and Garabogazköl Bay region),where sandstorms occurred in Central Asia,and northern Caspian lowland desert became the most important low-emission dust source in Central Asia;and(4)the combined effect of soil moisture and air temperature has the most significant influence on dust weather in Central Asia.This study provides a theoretical basis for sand prevention and sand control in Central Asia.In the future,Central Asia should focus on the rational utilization of land and water resources,and implement human interventions such as vegetation restoration and optimization of irrigation methods to curb further desertification in this area. 展开更多
关键词 Central Asia dust weather temporal and spatial distribution influencing factor Geodetector
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Characterizing the regulation mechanism of microbial community and metabolites in multi-layer vinegar starter(Cuqu)via Muqu fortification strategy 认领 引用
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作者 Qiuxiang Tang Nan Zhou +4 位作者 Jun Huang Jian Guo Xuemei Kang Wen Luo Rongqing Zhou 《Food Science and Human Wellness》 SCIE CAS CSCD 2026年第5期2115-2126,共12页
Improving the quality of Cuqu is one of the necessary strategies increasing the quality and yield of fresh vinegar.Enhancing the consistency and characteristics of Cuqu is currently a prominent area of research.Here,w... Improving the quality of Cuqu is one of the necessary strategies increasing the quality and yield of fresh vinegar.Enhancing the consistency and characteristics of Cuqu is currently a prominent area of research.Here,we investigated the impact of fortified Muqu(FM)consisting of Bacillus velezensis and Bacillus subtilis on enhancing the quality of Cuqu compared to conventional Muqu(CM).Our results demonstrated that FM significantly increased the abundance of Bacillus by 1.85-8.19 times,as well as substantially elevated Kroppenstedtia abundance in Cuqu.Source Tracker analysis revealed a higher proportion of bacteria originating from FM in Cuqu compared to those derived from CM,indicating superior environmental adaptability for bacteria in the FM.Additionally,upregulation in expression levels of pyrazine-related key enzymes within Cuqu microbial communities was observed due to FM,resulting in a remarkable 39.70-fold increase in pyrazine compounds production.Multiphase detection technology confirmed that FM improved similarity in microbial community structure and function at different spatial positions within Cuqu.These results elucidated the regulatory function of FM in forming microbial communities and metabolic mechanisms within Cuqu,providing valuable insights for optimizing and predicting traditional fermentation processes in industrial production. 展开更多
关键词 Microbial communities Metabolites pattern Spatial distributions Pyrazine content
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Identification of coal-rock interface under uniaxial compression using electric potential method 认领 引用
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作者 Tiancheng Shan Zhonghui Li +6 位作者 Enyuan Wang Haishan Jia Xin Zhang Qiming Zhang Xiaoran Wang Yue Niu Shishi Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第5期3483-3498,共16页
The instability of composite coal-rock structures can easily trigger severe dynamic disasters,such as rockbursts.The application of electric potential(EP)method shows promise for disaster prediction and accurate ident... The instability of composite coal-rock structures can easily trigger severe dynamic disasters,such as rockbursts.The application of electric potential(EP)method shows promise for disaster prediction and accurate identification of coal-rock interfaces.In this study,uniaxial compression experiments were conducted to monitor the EP spatiotemporal response of fine sandstone-coal and coarse sandstone-coal combined samples.EP distribution contour maps and three-dimensional(3D)EP models were utilized to explore the failure mechanisms and identify the interface state.Then the relationship between EP response and force field was examined through numerical simulations.An EP-based multifractal method was utilized to predict rock failure.Results show that the intensity and polarity of EPs differ between coal and rock but are correlated with stress state.The progressive failure features of two types of combined samples differ,triggering distinct EP responses.In the EP contour maps,the EP level increases with increasing height,and a low-intensity signal band appears around the interface before failure.When failure occurs,the EP field changes,and the low-intensity signal band becomes distorted.The 3D EP models effectively visualize the progressive failure of combined samples and clearly identify the interface location,similar to acoustic emission(AE)location.The evolution of force chain field is closely related to EP generation,and sparse strong force chain fields leads to a significant increase in EP level.Furthermore,the EPs display multifractal features,with precursory information being reflected in Δα and Δf.This study provides new ideas for early-warning of composite coal-rock and coal-rock interface identification. 展开更多
关键词 Coal-rock samples Electric potential method Mechanical response feature Spatial distribution imaging Interface identification Uniaxial compressive failure
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Multipoint Deformation Prediction Model Based on Clustering Partition of Extra High-Arch Dams 认领 引用
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作者 Bin Ou Haoquan Chi +3 位作者 Xu’an Qian Shuyan Fu Zhirui Miao Dingzhu Zhao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2026年第1期546-576,共31页
Deformation prediction for extra-high arch dams is highly important for ensuring their safe operation.To address the challenges of complex monitoring data,the uneven spatial distribution of deformation,and the constru... Deformation prediction for extra-high arch dams is highly important for ensuring their safe operation.To address the challenges of complex monitoring data,the uneven spatial distribution of deformation,and the construction and optimization of a prediction model for deformation prediction,a multipoint ultrahigh arch dam deformation prediction model,namely,the CEEMDAN-KPCA-GSWOA-KELM,which is based on a clustering partition,is pro-posed.First,the monitoring data are preprocessed via variational mode decomposition(VMD)and wavelet denoising(WT),which effectively filters out noise and improves the signal-to-noise ratio of the data,providing high-quality input data for subsequent prediction models.Second,scientific cluster partitioning is performed via the K-means++algorithm to precisely capture the spatial distribution characteristics of extra-high arch dams and ensure the consistency of deformation trends at measurement points within each partition.Finally,CEEMDAN is used to separate monitoring data,predict and analyze each component,combine the KPCA(Kernel Principal Component Analysis)and the KELM(Kernel Extreme Learning Machine)optimized by the GSWOA(Global Search Whale Optimization Algorithm),integrate the predictions of each component via reconstruction methods,and precisely predict the overall trend of ultrahigh arch dam deformation.An extra high arch dam project is taken as an example and validated via a comparative analysis of multiple models.The results show that the multipoint deformation prediction model in this paper can combine data from different measurement points,achieve a comprehensive,precise prediction of the deformation situation of extra high arch dams,and provide strong technical support for safe operation. 展开更多
关键词 Extra high arch dams deformation prediction data noise reduction spatial distribution clustering partition
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Spatial-Temporal Variations of Bacterioplankton Community Assemblages and Functional Attributes in the Beibu Gulf,Northern South China Sea 认领 引用
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作者 SUN Pengfei YANG Tinglong +4 位作者 LIAN Jie LI Hui WANG Weimin ZHU Zuhao TAN Yongyu 《Journal of Ocean University of China》 SCIE CAS CSCD 2026年第2期717-730,I0036-I0038,共14页
This study used amplicon sequencing of the 16S rRNA gene to explore the community composition and functional attributes of inshore and offshore bacterioplankton in the Beibu Gulf during summer and winter.Results showe... This study used amplicon sequencing of the 16S rRNA gene to explore the community composition and functional attributes of inshore and offshore bacterioplankton in the Beibu Gulf during summer and winter.Results showed a spatial and temporal variation that the inshore and offshore waters in both seasons were significantly different from each other(P<0.05).The abundance of bacterioplankton in summer was higher than winter,with a trend toward higher abundance in inshore than in the offshore.Candidatus Actinomarina,and Synechococcus were the dominant genera between inshore and offshore waters in both seasons.The richness and diversity of bacterioplankton in inshore waters were higher than in offshore waters,and were significantly higher in winter than in summer(P<0.05).The bacterioplankton community was affected by temperature and pH in inshore waters during summer.The dissolved inorganic nitrogen,nitrate,nitrite,and dissolved oxygen affected the inshore waters in winter.We found the bacterioplankton community and structure in inshore waters were mainly affected by West-Guangdong coastal current water mass and terrigenous factors in winter,and affected by terrigenous factors in summer.The Tax4Fun functional abundance analysis showed that the overall functional profiles of the bacterioplankton community in inshore and offshore waters were similar on level 1,but some main functional genes were significantly different at levels 2 and 3.These research findings have provided valuable insights into the crucial roles of bacterioplankton in the ecosystem and its biogeochemical cycles in the Beibu Gulf. 展开更多
关键词 bacterioplankton community spatial and temporal distribution function attributes environmental factors Beibu Gulf
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Influenceof bacterial concentration and fissure aperture on improving dynamic mechanical properties of MICP repaired fissured sandstone 认领 引用 被引量：1
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作者 Zhihui Cui Xiang He +2 位作者 Feng Dai Yi Liu Shanghui Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第2期1213-1232,共20页
Fissured rocks are prevalent in geotechnical engineering and can significantlyimpact the stability of engineering structures.Microbial-induced carbonate precipitation(MICP)technology provides an ecofriendly solution f... Fissured rocks are prevalent in geotechnical engineering and can significantlyimpact the stability of engineering structures.Microbial-induced carbonate precipitation(MICP)technology provides an ecofriendly solution for repairing fissuredrocks.To optimize repair effectiveness,this study firstinvestigated the effects of environmental factors on bacterial growth,urease activity,and calcium carbonate yield.The optimal MICP scheme was determined to be a pH of 9,a temperature of 25℃,and a cementation solution concentration of 0.5 mol/L.Subsequently,the sandstone specimens with various fissureapertures were repaired using MICP with different bacterial concentrations.Dynamic tests were carried out on the repaired specimens using a split Hopkinson pressure bar system.The experimental results indicate that the dynamic strength of the MICP-repaired specimens positively correlates with strain rate,but decreases with increasing bacterial concentration and fissureaperture.These factors have little effect on the progressive failure behavior.Surface cracks were mainly compression-shear cracks in the repair area and tensile-shear cracks at the end of the specimen.Moreover,the crystal morphology observed by scanning electron microscope indicates that MICP primarily produces vaterite crystals,and lower bacterial concentrations favor the formation of more stable calcite crystals,thereby enhancing the cementitious properties.Furthermore,X-ray computed tomography demonstrates an uneven distribution of calcium carbonate within fissures,with higher fillingrates observed at the injection end and at the bottom of the fissures.Lower bacterial concentrations and smaller fissureapertures are conducive to more uniform distribution and increased fillingrate of calcium carbonate,with fissureaperture exerting a more dominant influence. 展开更多
关键词 Microbial Induced Carbonate Precipitation (MICP) Fissured sandstone Fissure repair Dynamic mechanical properties Spatial distribution
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Phytoplankton-and Physical-Regulated Dissolved Inorganic Nutrient Dynamics in the Amundsen Sea During Austral Summer 认领 引用
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作者 GENG Yunshang ZHAO Jun +6 位作者 ZHANG Haifeng YANG Xufeng ZHU Changfeng CHEN Lishi SUN Yongming HUANG Wenhao PAN Jianming 《Journal of Ocean University of China》 SCIE CAS CSCD 2026年第2期702-716,I0026-I0035,共15页
The Southern Ocean is critical for global marine primary productivity and ecosystem functioning.However,the spatiotemporal dynamics of dissolved nutrients in the Amundsen Sea remain poorly understood.We analyzed nutri... The Southern Ocean is critical for global marine primary productivity and ecosystem functioning.However,the spatiotemporal dynamics of dissolved nutrients in the Amundsen Sea remain poorly understood.We analyzed nutrient samples collected from the Amundsen Sea Polynya(ASP)and adjacent open ocean during the 38 th Chinese National Antarctic Research Expedition.Integrating existing datasets,we identified nutrient distribution patterns and monthly variations driven by biological and physical processes.The ASP mixed layer exhibited the lowest nitrate concentrations(mean 12.07±5.94μmol/L,minimum 1.74μmol/L),indicating potential nitrate limitation;whereas the open ocean mixed layer displayed the lowest silicate levels(45.59±12.03μmol/L).These contrasting nutrient regimes reflect distinct phytoplankton bloom characteristics:Phaeocystis antarctica dominates the ASP,while diatoms prevail in the open ocean.Unlike nitrate and silicate,surface phosphate concentrations were controlled by sea ice retreat,with upwelling of Circumpolar Deep Water or katabatic winds effectively replenishing phosphate in nearshore areas.Seasonal progression reveals dynamic nutrient depletion and replenishment cycles.As sea ice retreated and phytoplankton blooms progressed,dissolved inorganic nitrogen(DIN)in the ASP declined sharply from 16.11±5.85μmol/L(December)to 9.46±4.55μmol/L(February),while silicate decreased from 80.26±3.96μmol/L(early-mid January)to 63.83±5.51μmol/L(February).Both nutrients were subsequently replenished by March(DIN:19.92±6.31μmol/L;silicate:78.53±9.41μmol/L).This asynchronous depletion pattern mirrors the ecological succession from P.antarctica-to diatoms-dominated growth.These findings enhance understanding of nutrient cycling in Antarctic marginal seas and establish a critical baseline for assessing biogeochemical feedback under climate warming. 展开更多
关键词 Amundsen Sea dissolved inorganic nutrients nitrate limitation spatial distribution monthly variation
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Coupled effects of fracture spatial distribution and rock matrix permeability on tunnel water inflow:An embedded discrete fracture model based investigation 认领 引用
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作者 Yu ZHANG Xiaojun LI +2 位作者 Tao LI Hehua ZHU Yi RUI 《ENGINEERING Structure and Civil Engineering》 SCIE EI CAS CSCD 2026年第2期380-403,共24页
Groundwater inflow constitutes a critical challenge in rock tunnel engineering.This study systematically investigates the coupled effects of fracture spatial distribution and rock matrix permeability on tunnel water i... Groundwater inflow constitutes a critical challenge in rock tunnel engineering.This study systematically investigates the coupled effects of fracture spatial distribution and rock matrix permeability on tunnel water inflow using a novel embedded discrete fracture model based method.A set of quadratic regression models is established to delineate the relationship between inflow rate and fracture distribution parameters over a wide range of fracture-to-matrix permeability ratios(kf/km).Results demonstrate that fracture aperture,spacing,and their interaction dominate the inflow across all permeability ratios.Analysis of variance further reveals a threshold-dependent behavior:coupled effects are significant below a critical kf/km value but decay markedly above it.This threshold decreases with larger aperture and increases with wider spacing,yet remains nearly independent of fracture dip angle.Moreover,when kf/km is below the threshold,aperture and spacing exert greater influence on tunnel inflow at lower permeability ratios,while kf/km gains influence under larger apertures and smaller spacings.Finally,a case study of Nanwan Tunnel shows that matrix permeability plays a dual role—increasing the mean inflow rate while reducing uncertainty from stochastic fracture distribution. 展开更多
关键词 tunnel water inflow fractured rock tunnel fracture spatial distribution rock matrix permeability embedded discrete fracture model fracture-to-matrix permeability ratio
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DCAD:a Dual Clustering Algorithm for Distributed Spatial Databases 认领 引用 被引量：16
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作者 ZHOU Jiaogen GUAN Jihong LI Pingxiang 《Geo-Spatial Information Science》 EI 2007年第2期137-144,共8页
Spatial objects have two types of attributes： geometrical attributes and non-geometrical attributes, which belong to two different attribute domains （geometrical and non-geometrical domains）. Although geometrically... Spatial objects have two types of attributes： geometrical attributes and non-geometrical attributes, which belong to two different attribute domains （geometrical and non-geometrical domains）. Although geometrically scattered in a geometrical domain, spatial objects may be similar to each other in a non-geometrical domain. Most existing clustering algorithms group spatial datasets into different compact regions in a geometrical domain without considering the aspect of a non-geometrical domain. However, many application scenarios require clustering results in which a cluster has not only high proximity in a geometrical domain, but also high similarity in a non-geometrical domain. This means constraints are imposed on the clustering goal from both geometrical and non-geometrical domains simultaneously. Such a clustering problem is called dual clustering. As distributed clustering applications become more and more popular, it is necessary to tackle the dual clustering problem in distributed databases. The DCAD algorithm is proposed to solve this problem. DCAD consists of two levels of clustering： local clustering and global clustering. First, clustering is conducted at each local site with a local clustering algorithm, and the features of local clusters are extracted clustering is obtained based on those features fective and efficient. Second, local features from each site are sent to a central site where global Experiments on both artificial and real spatial datasets show that DCAD is effective and efficient. 展开更多
关键词 distributed clustering dual clustering distributed spatial database
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The Role of Water Conservancy Projects in Flood and Drought Disaster Defense and Optimization Strategies 认领 引用
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作者 Guo Juan 《China's Foreign Trade》 2026年第2期33-37,共5页
"In the times of Yao and Shun,there was a great flood in the Yellow River basin.Yu led people in surveying and digging through mountains and in dredging rivers.It took thirteen years to subdue the flood."Sin... "In the times of Yao and Shun,there was a great flood in the Yellow River basin.Yu led people in surveying and digging through mountains and in dredging rivers.It took thirteen years to subdue the flood."Since ancient times,conducting water conservancy projects to keep the country safe and prosper the people has been the main proposition of the China's national struggle against natural disasters.The monsoon climate and natural geographical conditions in China determine that the temporal and spatial distribution of water resources is extremely uneven and the resulting complex risks of flood and drought disasters. 展开更多
关键词 drought disaster defense Yao Shun era water conservancy projects optimization strategies flood disaster defense surveying digging mountains Yellow River basin temporal spatial distribution
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Spatial Distribution Patterns of Traditional Villages and Their Influencing Factors in the Southeastern Shanxi Region 认领 引用
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作者 Wenjie Yu Jichen Shen Rong Peng 《Journal of Architectural Research and Development》 2026年第4期48-57,共10页
The study of the overall spatial distribution of traditional villages is of great significance for a comprehensive understanding of traditional villages from the perspectives of nature,economy,society,and culture.Taki... The study of the overall spatial distribution of traditional villages is of great significance for a comprehensive understanding of traditional villages from the perspectives of nature,economy,society,and culture.Taking the top six batches of national level traditional villages in Southeastern Shanxi as the research object,this study quantitatively investigates the factors affecting the spatial distribution of traditional villages using methods such as nearest neighbor index,Moran index,and quantitative geography.The study explores the factors such as terrain,watershed,and transportation that affect the spatial distribution of traditional villages.The results show that:1)the overall distribution of traditional villages in Southeastern Shanxi presents a clustered geographical spatial feature,with a distribution pattern of“dual cores and one belt”.2)The spatial distribution of traditional villages is the result of the combined effects of terrain,water systems,economic development level,transportation network,and other factors.The natural environment is the basic factor affecting distribution,while cultural economy is the internal driving force for village development.Based on the above results analysis,it is necessary to actively explore a cluster based protection framework for the current situation of traditional village protection in Southeastern Shanxi.According to the different degrees of impact of each element on traditional villages,the connection and role between each element should be strengthened as a reference for formulating differentiated policies. 展开更多
关键词 Southeastern Shanxi Traditional villages Spatial distribution pattern Influencing factors
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Spatial differentiation of carbon emissions from energy consumption based on machine learning algorithm:A case study during 2015–2020 in Shaanxi,China 认领 引用 被引量：5
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作者 Hongye Cao Ling Han +1 位作者 Ming Liu Liangzhi Li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2025年第3期358-373,共16页
Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research probl... Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research problem.Previous studies relied on statistical regression models that failed to capture the complex nonlinear relationships between carbon emissions and characteristic variables.In this study,we propose a machine learning algorithm for carbon emissions,a Bayesian optimized XGboost regression model,using multi-year energy carbon emission data and nighttime lights(NTL)remote sensing data from Shaanxi Province,China.Our results demonstrate that the XGboost algorithm outperforms linear regression and four other machine learning models,with an R2of 0.906 and RMSE of 5.687.We observe an annual increase in carbon emissions,with high-emission counties primarily concentrated in northern and central Shaanxi Province,displaying a shift from discrete,sporadic points to contiguous,extended spatial distribution.Spatial autocorrelation clustering reveals predominantly high-high and low-low clustering patterns,with economically developed counties showing high-emission clustering and economically relatively backward counties displaying low-emission clustering.Our findings show that the use of NTL data and the XGboost algorithm can estimate and predict carbon emissionsmore accurately and provide a complementary reference for satellite remote sensing image data to serve carbon emission monitoring and assessment.This research provides an important theoretical basis for formulating practical carbon emission reduction policies and contributes to the development of techniques for accurate carbon emission estimation using remote sensing data. 展开更多
关键词 Machine learning Energy carbon emissions Nighttime light Spatial distribution
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Occurrence and potential risks of organophosphate esters in agricultural soils:A case study of Fuzhou City,Southeast China 认领 引用 被引量：2
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作者 Tao Wang Hong Zhang +6 位作者 Chong Huang Yujie Ben Hanlin Zhou Hangting Guo Yonghe Han Yong Zhang Ping Tong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2025年第4期571-581,共11页
Fifty agricultural soil samples collected from Fuzhou,southeast China,were first investigated for the occurrence,distribution,and potential risks of twelve organophosphate esters(OPEs).The total concentration of OPEs(... Fifty agricultural soil samples collected from Fuzhou,southeast China,were first investigated for the occurrence,distribution,and potential risks of twelve organophosphate esters(OPEs).The total concentration of OPEs(ΣOPEs)in soil ranged from 1.33 to 96.5 ng/g dry weight(dw),with an average value of 17.1 ng/g dw.Especially,halogenated-OPEs were the predominant group with amean level of 9.75 ng/g dw,and tris(1-chloro-2-propyl)phosphate(TCIPP)was the most abundant OPEs,accounting for 51.1%ofΣOPEs.The concentrations of TCIPP andΣOPEs were found to be significantly higher(P<0.05)in soils of urban areas than those in suburban areas.In addition,the use of agricultural plastic films and total organic carbon had a positive effect on the occurrence of OPE in this study.The positive matrix factorization model suggested complex sources of OPEs in agricultural soils from Fuzhou.The ecological risk assessment demonstrated that tricresyl phosphate presented a medium risk to land-based organisms(0.1≤risk quotient<1.0).Nevertheless,the carcinogenic and noncarcinogenic risks for human exposure to OPEs through soil ingestion and dermal absorption were negligible.These findings would facilitate further investigations into the pollution management and risk control of OPEs. 展开更多
关键词 Organophosphate esters(OPEs) Agricultural soils Spatial distribution Source identification Risk assessment
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Spatial distribution,influencing factors,and environmental risk assessments of mercury in surface soils over Xinjiang,northwestern China 认领 引用 被引量：1
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作者 Zhengzheng Yang Shiwei Sun +5 位作者 Xiwen Miao Shichang Kang Pengfei Chen Dipesh Rupakheti Zhaofu Hu Junming Guo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2025年第12期555-568,共14页
Since scarce knowledge of soil mercury(Hg)concentrations and risks in the vulnerable Xinjiang,topsoils(0-15 cm)from its typical landscapes were extensively sampled.Topsoil total mercury(THg)concentrations varied broad... Since scarce knowledge of soil mercury(Hg)concentrations and risks in the vulnerable Xinjiang,topsoils(0-15 cm)from its typical landscapes were extensively sampled.Topsoil total mercury(THg)concentrations varied broadly between 0.9 and 35.3 ng/g,of which16.8%exceeded the background value of soil Hg for Xinjiang.Topsoil THg concentrations across various landscapes exhibited a declining order:farmland(11.7±6.0 ng/g)>grassland(10.5±8.5 ng/g)>woodland(10.2±8.2 ng/g)>desert(7.0±5.8 ng/g).The average topsoil THg concentration was higher in northwestern Xinjiang(11.3±7.2 ng/g)than that in southeastern Xinjiang(6.3±6.1 ng/g).Relatively high topsoil THg concentrations were observed near the cities with intensive human activities,followed by a gradual decline to the surroundings.The concentrations of topsoil THg were strongly correlated with the contents of total organic carbon(TOC),clay,silty,and sandy,and the distance from each sampling site to its nearest city,suggesting that the variation of topsoil Hg was significantly influenced by TOC content,soil granularity,and anthropogenic Hg emissions.Silty and TOC were the principal affecting factors,explaining 48.7%and 7.9%of the THg variation,respectively.The contamination and potential ecological risk evaluations revealed that topsoils in regions with dense populations were polluted with Hg and contained higher potential ecological risks.The health risk evaluations indicated that exposure risks of topsoil Hg were higher for children than those for adults.Fortunately,topsoil Hg posed acceptable risks to human health. 展开更多
关键词 Mercury Topsoil Landscape Spatial distribution Risk assessment Xinjiang
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Characterization and function of particulate organic matter:Evidence from lakes undergoing ecological restoration 认领 引用 被引量：1
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作者 Letian Zhang Wenqiang Zhang +2 位作者 Hao Guo Baoqing Shan Dongyang Wei 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2025年第4期91-103,共13页
Particulate organic matter(POM)plays a crucial role in the organic composition of lakes;however,its characteristics remain poorly understood.This study aimed to characterize the structure and composition of POM in Lak... Particulate organic matter(POM)plays a crucial role in the organic composition of lakes;however,its characteristics remain poorly understood.This study aimed to characterize the structure and composition of POM in Lake Baiyangdian usingmany kinds of techniques and investigate the effects of different extracted forms of POM on water quality.The suspended particulatematter in the lake had complex compositions,with its components primarily derived from aquatic plants and their detritus.The organic matter content of the suspended particulatematterwas relatively high(organic carbon content 27.29–145.94 g/kg)for the sum of three extractable states(water-extracted organic matter[WEOM],humic acid,and fulvic acid)and one stable bound state(humin).Spatial distribution analysis revealed that the POM content in the water increased from west to east,which was consistent with the water flow pattern influenced by the Baiyangdian water diversion project.Fluorescence spectroscopy analysis of the WEOM showed three prominent peaks with excitation/emission wavelengths similar to those of dissolved organic matter peaks.These peaks were potentially initial products of POM conversion into dissolved organic matter.Furthermore,the intensity of the WEOM fluorescence peak(total fluorescence peak intensity)was negatively correlated with the inorganic nitrogen concentration in water(p<0.01),while the intensity of the HA fluorescence peak showed a positive correlation with the inorganic nitrogen concentration(p<0.01).This suggested that exogenous organic matter inputs led to the diffusion of alkaline dissolved nitrogen from sediment intowater,while degradation processes of aquatic plant debris contributed to the decrease in inorganic nitrogen concentrations in the water column.These findings enhance our understanding of POM characteristics in shallow lakes and the role of POM in shallow lake ecosystems. 展开更多
关键词 Lake baiyangdian Particulate organic matter Physical structure Spatial distribution Three-dimensional fluorescence spectroscopy
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Concentrations, spatial distribution, and human exposure of synthetic phenolic antioxidants in indoor dust from ten provinces in China 认领 引用 被引量：1
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作者 Xueyu Weng Wanyi Wang +2 位作者 Qingqing Zhu Chunyang Liao Guibin Jiang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2025年第6期584-593,共10页
Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples w... Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples were collected from 10 provinces in China,and six SPAs(three parent SPAs and their three transformation products)were analyzed.The concentrations of6SPAs(the sum of six target compounds)ranged from 15.4 to 3210 ng/g(geometric mean(GM):169 ng/g).The highest concentration of6SPAswas found in Sichuan Province(GM:349 ng/g),which was approximately 4 times higher than that in Hubei Province(81.6 ng/g)(p<0.05).The concentrations of butylated hydroxytoluene(BHT),2,2'-methylene bis(4-methyl-6–tert-butylphenol)(AO2246),2,6-di–tert–butyl–1,4-benzoquinone(BHT-Q),2,6-di–tert–butyl–4-(hydroxymethyl)phenol(BHT-OH),and ∑p-SPAs were substantially higher in dust from urban areas than rural areas(p<0.05).AO2246 concentration in dust from homes(GM:0.400 ng/g)was about 4 times higher than that in workplaces(0.116 ng/g)(p<0.01).Significantly higherp-SPAs concentrations were found in dust from homes(GM:17.5 ng/g)than workplaces(11.4 ng/g)(p<0.01).The estimated daily intakes(EDIs)of ∑6SPAs exposed through dust ingestion were 0.582,0.342,0.197,0.076,and 0.080 ng/kg bw/day in different age groups,and exposed through dermal contact was 0.358,0.252,0.174,0.167,and 0.177 ng/kg bw/day.EDIs showed that the exposure risks of SPAs decreased with age.This is the first work to determine SPAs in dust from10 provinces in China and investigate the spatial distribution of SPAs in those regions. 展开更多
关键词 Indoor dust Synthetic phenolic antioxidants Spatial distribution Composition profile Human exposure
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