The functionalization of living cells,both internally and externally,transforming them into microma-chines with specified functions,holds significant po-tential in fields such as biosensing,biocomputing,and intelligen...The functionalization of living cells,both internally and externally,transforming them into microma-chines with specified functions,holds significant po-tential in fields such as biosensing,biocomputing,and intelligent theranostics.However,due to the complexity and dynamic nature of living cells,it remains challenging to allocate exogenous function-al materials to specific locations within the cell or on its surface and maintain their positions stable for a reasonable period.Here,we devise a DNA-pro-grammed cargo distributing system(DCD),capable of distributing functional modules to the cell mem-brane or within the cell as needed.This system includes an amphiphilic DNA structure for determin-ing the destination of the cargo and a DNA connector carried on it for recognizing the DNA-encoded cargo.We test three different morphologies of amphiphilic DNA structures and find that their efficiencies in cell surface retention and cell internalization significantly varied,enabling the distribution of nanoparticle cargos on the cell membrane and within the cell in distinct proportions.Their positions can remain sta-ble for at least 6 h.Moreover,this allocation method shows specificity,which minimizes the deployment of mismatched cargo.This method provides new tools for the modular construction of cellular micro-machines.展开更多
The new energy power generation is becoming increasingly important in the power system.Such as photovoltaic power generation has become a research hotspot,however,due to the characteristics of light radiation changes,...The new energy power generation is becoming increasingly important in the power system.Such as photovoltaic power generation has become a research hotspot,however,due to the characteristics of light radiation changes,photovoltaic power generation is unstable and random,resulting in a low utilization rate and directly affecting the stability of the power grid.To solve this problem,this paper proposes a coordinated control strategy for a newenergy power generation system with a hybrid energy storage unit based on the lithium iron phosphate-supercapacitor hybrid energy storage unit.Firstly,the variational mode decomposition algorithm is used to separate the high and low frequencies of the power signal,which is conducive to the rapid and accurate suppression of the power fluctuation of the energy storage system.Secondly,the fuzzy control algorithm is introduced to balance the power between energy storage.In this paper,the actual data is used for simulation,and the simulation results show that the strategy realizes the effective suppression of the bus voltage fluctuation and the accurate control of the internal state of the energy storage unit,effectively avoiding problems such as overshoot and over-discharge,and can significantly improve the stability of the photovoltaic power generation systemand the stability of the Direct Current bus.It is of great significance to promote the development of collaborative control technology for photovoltaic hybrid energy storage units.展开更多
This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expan...This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expansion with environmental protection,a comprehensive evaluation index system is constructed,encompassing two key dimensions:regional economy and ecological environment.Using panel data from 2013 to 2022,the coupling coordination degree model is employed to quantify the interactions and synergy between these dimensions.Additionally,spatial econometric methods are applied to calculate both global and local Moran’s Index,revealing spatial clustering patterns,regional disparities,and heterogeneity.The relative development model further identifies critical factors influencing regional coordination,with a focus on the lagging development of basic infrastructure and public services.The findings demonstrate a positive temporal trend toward improved regional coordination and reduced development gaps,with a spatial pattern characterized by higher coupling degrees in eastern and central regions compared to western areas.Based on these results,this study proposes actionable strategies to enhance coordinated development,emphasizing ecological conservation,the establishment of green production and consumption systems,ecological restoration,and strengthened municipal collaboration.This revised abstract emphasizes the study’s purpose,methods,and key findings more clearly while maintaining a professional and concise tone.Finally,based on the above analysis results,the corresponding coordinated development suggestions of regional economy and ecological environment are given from the aspects of ecological environment protection measures,green production and consumption system construction,ecological environment restoration and municipal coordination.展开更多
The electrochemical corrosion of ductile pipes(DPs)in drinking water distribution systems(DWDS)has a crucial impact on cement-mortar lining(CML)failure and metal release,potentially leading to drinking water quality d...The electrochemical corrosion of ductile pipes(DPs)in drinking water distribution systems(DWDS)has a crucial impact on cement-mortar lining(CML)failure and metal release,potentially leading to drinking water quality deterioration and posing a risk to public health.An in-situ scanning vibrating electrode technique(SVET)with micron-scale resolution,microscopic scale detection and water quality analysis were used to investigate the corrosion behavior and metal release from DPs throughout the whole CML failure process.Metal pollutants release occurred at three different stages of CML failure process,and there are potential risks of water quality deterioration exceeding the maximum allowable levels set by national standards in the partial failure stage and lining peeling stage.Furthermore,the effects of water chemistry(Cl^(−),SO_(4)^(2−),NO_(3)−,and Ca^(2+))on corrosion scale growth and iron release activity,were investigated during the CML partial failure stage.Results showed that the CML failure process in DPs was accelerated by the autocatalysis of localized corrosion.Cl^(−)was found to damage the uncorroded metal surface,while SO_(4)^(2−)mainly dissolved the corrosion scale surface,increasing iron release.Both the oxidation of NO_(3)−and selective sedimentation of Ca2+were found to enhance the stability of corrosion scales and inhibit iron release.展开更多
The technology of electric propulsion aircraft(EPA)represents an important direction and an advanced stage in the development of aviation electrification.It is a key pathway for green development in aviation industry ...The technology of electric propulsion aircraft(EPA)represents an important direction and an advanced stage in the development of aviation electrification.It is a key pathway for green development in aviation industry and can significantly enhance the energy efficiency of aircraft propulsion system.Electric motor is the most critical electromechanical energy conversion component in an aircraft electric propulsion system(EPS).High-performance electric motors,power electronic converters and EPS control form the foundation of the EPA.This paper provides an overview of the characteristics of electric motors for EPA,analyzes the inverter topologies of EPSs,and reviews ongoing EPA projects.The article highlights the latest advancements in three types of motors:superconducting motors(SCMs),permanent magnet synchronous motors(PMSMs),and induction motors(IMs).It summarizes the control system architectures of current EPA initiatives and,building on this foundation,proposes future research directions for EPSs.These include cutting-edge areas such as high-performance motors and advanced manufacturing technologies,Ga N-or Si C-based inverter integration and innovation,electric propulsion control systems,and optimization of wiring systems.展开更多
Modern aircraft tend to use fuel thermal management systems to cool onboard heat sources.However,the design of heat transfer architectures for fuel thermal management systems relies on the experience of the engineers ...Modern aircraft tend to use fuel thermal management systems to cool onboard heat sources.However,the design of heat transfer architectures for fuel thermal management systems relies on the experience of the engineers and lacks theoretical guidance.This paper proposes a concise graph representation method based on graph theory for fuel thermal management systems,which can represent all possible connections between subsystems.A generalized optimization algorithm is proposed for fuel thermal management system architecture to minimize the heat sink.This algorithm can autonomously arrange subsystems with heat production differences and efficiently utilize the architecture of the fuel heat sink.At the same time,two evaluation indices are proposed from the perspective of subsystems.These indices intuitively and clearly show that the reason for the high efficiency of heat sink utilization is the balanced and moderate cooling of each subsystem and verify the rationality of the architecture optimization method.A set of simulations are also conducted,which demonstrate that the fuel tank temperature has no effect on the performance of the architecture.This paper provides a reference for the architectural design of aircraft fuel thermal management systems.The metrics used in this paper can also be utilized to evaluate the existing architecture.展开更多
The effects of disinfectants and plasmid-based antibiotic resistance genes(ARGs)on the growth of microorganisms and the plasmid-mediated transfer of ARGs in the water and biofilm of the drinkingwater distribution syst...The effects of disinfectants and plasmid-based antibiotic resistance genes(ARGs)on the growth of microorganisms and the plasmid-mediated transfer of ARGs in the water and biofilm of the drinkingwater distribution system under simulated conditionswere explored.The heterotrophic plate count of the water in reactors with 0.1 mg/L NaClO and NH_(2)Cl was higher than in the control groups.Therewas no similar phenomenon in biofilm.In thewater of reactors containing NaClO,the aphA and bla geneswere lower than in the antibiotic resistant bacteria group,while both genes were higher in the water of reactors with NH_(2)Cl than in the control group.Chloramine may promote the transfer of ARGs in the water phase.Both genes in the biofilm of the reactors containing chlorine were lower than the control group.Correlation analysis between ARGs and water quality parameters revealed that the copy numbers of the aphA gene were significantly positively correlated with the copy numbers of the bla gene in water and significantly negatively correlated in biofilm(p<0.05).The results of the sequencing assay showed that bacteria in the biofilm,in the presence of disinfectant,were primarily Gram-negative.1.0 mg/L chlorine decreased the diversity of the community in the biofilm.The relative abundance of some bacteria that may undergo transfer increased in the biofilm of the reactor containing 0.1 mg/L chlorine.展开更多
Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including at...Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.展开更多
This paper introduces an optimized planning approach for integrating photovoltaic as distributed generation (PV-DG) into the radial distribution power systems, utilizing exhaustive load flow (ELF), loss sensitivity fa...This paper introduces an optimized planning approach for integrating photovoltaic as distributed generation (PV-DG) into the radial distribution power systems, utilizing exhaustive load flow (ELF), loss sensitivity factor (LSF), genetic algorithms (GA) methods, and numerical method based on LSF. The methodology aims to determine the optimal allocation and sizing of multiple PV-DG to minimize power loss through time series power flow analysis. An approach utilizing continuous sensitivity analysis is developed and inherently leverages power flow and loss equations to compute LSF of all buses in the system towards employing a dynamic PV-DG model for more accurate results. The algorithm uses a numerical grid search method to optimize PV-DG placement in a power distribution system, focusing on minimizing system losses. It combines iterative analysis, sensitivity assessment, and comprehensive visualization to identify and present the optimal PV-DG configurations. The present-ed algorithms are verified through co-simulation framework combining MATLAB and OpenDSS to carry out analysis for 12-bus radial distribution test system. The proposed numerical method is compared with other algorithms, such as ELF, LSF methods, and Genetic Algorithms (GA). Results show that the proposed numerical method performs well in comparison with LSF and ELF solutions.展开更多
To overcome the limitations of microscale experimental techniques and molecular dynamics(MD)simulations,a coarse-grained molecular dynamics(CGMD)method was used to simulate the wetting processes of clay aggregates.Bas...To overcome the limitations of microscale experimental techniques and molecular dynamics(MD)simulations,a coarse-grained molecular dynamics(CGMD)method was used to simulate the wetting processes of clay aggregates.Based on the evolution of swelling stress,final dry density,water distribution,and clay arrangements under different target water contents and dry densities,a relationship between the swelling behaviors and microstructures was established.The simulated results showed that when the clay-water well depth was 300 kcal/mol,the basal spacing from CGMD was consistent with the X-ray diffraction(XRD)data.The effect of initial dry density on swelling stress was more pronounced than that of water content.The anisotropic swelling characteristics of the aggregates are related to the proportion of horizontally oriented clay mineral layers.The swelling stress was found to depend on the distribution of tactoids at the microscopic level.At lower initial dry density,the distribution of tactoids was mainly controlled by water distribution.With increase in the bound water content,the basal spacing expanded,and the swelling stresses increased.Free water dominated at higher water contents,and the particles were easily rotated,leading to a decrease in the number of large tactoids.At higher dry densities,the distances between the clay mineral layers decreased,and the movement was limited.When bound water enters the interlayers,there is a significant increase in interparticle repulsive forces,resulting in a greater number of small-sized tactoids.Eventually,a well-defined logarithmic relationship was observed between the swelling stress and the total number of tactoids.These findings contribute to a better understanding of coupled macro-micro swelling behaviors of montmorillonite-based materials,filling a study gap in clay-water interactions on a micro scale.展开更多
Dear Editor,The letter deals with the distributed state and fault estimation of the whole physical layer for cyber-physical systems(CPSs) when the cyber layer suffers from DoS attacks. With the advancement of embedded...Dear Editor,The letter deals with the distributed state and fault estimation of the whole physical layer for cyber-physical systems(CPSs) when the cyber layer suffers from DoS attacks. With the advancement of embedded computing, communication and related hardware technologies, CPSs have attracted extensive attention and have been widely used in power system, traffic network, refrigeration system and other fields.展开更多
Both evolutionary computation(EC)and multiagent systems(MAS)study the emergence of intelligence through the interaction and cooperation of a group of individuals.EC focuses on solving various complex optimization prob...Both evolutionary computation(EC)and multiagent systems(MAS)study the emergence of intelligence through the interaction and cooperation of a group of individuals.EC focuses on solving various complex optimization problems,while MAS provides a flexible model for distributed artificial intelligence.Since their group interaction mechanisms can be borrowed from each other,many studies have attempted to combine EC and MAS.With the rapid development of the Internet of Things,the confluence of EC and MAS has become more and more important,and related articles have shown a continuously growing trend during the last decades.In this survey,we first elaborate on the mutual assistance of EC and MAS from two aspects,agent-based EC and EC-assisted MAS.Agent-based EC aims to introduce characteristics of MAS into EC to improve the performance and parallelism of EC,while EC-assisted MAS aims to use EC to better solve optimization problems in MAS.Furthermore,we review studies that combine the cooperation mechanisms of EC and MAS,which greatly leverage the strengths of both sides.A description framework is built to elaborate existing studies.Promising future research directions are also discussed in conjunction with emerging technologies and real-world applications.展开更多
Toxoplasma gondii(T.gondii)is a globally distributed parasite that can infect a diversity of warm-blooded animals,including swine and humans.Infection in swine poses a considerable threat to food safety and public hea...Toxoplasma gondii(T.gondii)is a globally distributed parasite that can infect a diversity of warm-blooded animals,including swine and humans.Infection in swine poses a considerable threat to food safety and public health.The aim of this meta-analysis was to estimate the seroprevalence of T.gondii infection in the swine population in China from 2000 to 2023 and to examine potential factors associated with infection.A total of 112 studies were included,collectively involving 145,152 swine samples originating from 26 provinces.The pooled seroprevalence was 26.0%(95%CI:23.3%–28.7%).Stratified analysis based on diagnostic methods revealed that studies using the indirect hemagglutination assay(IHA)reported a seroprevalence of 19.7%(95%CI:17.2%–22.2%),whereas those utilizing the enzyme-linked immunosorbent assay(ELISA)reported a higher seroprevalence of 35.5%(95%CI:29.1%–41.8%).Geographical analysis indicated higher seroprevalence in the South Central and Southwest regions,whereas the East and Northwest areas reported the lowest seroprevalence.Chongqing Province reported the highest seroprevalence,reaching 44.9%(95%CI:43.4%–46.0%),followed by Xinjiang,Hainan,and Guizhou,whereas the lowest was observed in Shandong Province(3.5%,95%CI:1.7%–6.1%).These findings provide important epidemiological evidence that can inform strategies for the prevention and control of T.gondii infection in swine populations,with a focus on high-risk populations and geographical areas.This imperative contributes substantially to the improvement of both food safety and public health.展开更多
Resilience studies for water distribution systems(WDS)coupled with other interdependent infrastructure systems attract increasing attention from stakeholders and researchers.However,most existing large-scale WDS model...Resilience studies for water distribution systems(WDS)coupled with other interdependent infrastructure systems attract increasing attention from stakeholders and researchers.However,most existing large-scale WDS models are single infrastructure-based without consideration of other infrastructure systems.This is due to a lack of needed information on systems coupling,the structure of the simulator used,and the computation load involved.To address these gaps,this paper presents a synthetic modeling framework for a real-world WDS as coordinating with other infrastructure systems via a building-mediated clustering approach through consideration of physical distance and node capacity.First,the WDS network topology and operation parameters are inferred via bulk open-source information.A building-mediated clustering approach is designed to systematically derive the interdependence between the WDS and the power system similarly created as a case study.Second,a novel linearization method is developed in formulating the WDS model that can relieve computation load while maintaining accuracy.Finally,a disruption-recovery framework is developed to demonstrate the proposed methodology in modelling WDS resilience.The framework is applied to a neighborhood in Queenstown,Singapore,an area of 20.43 km^(2) and 96,000 population.The near-real-time simulations on the coupled system involving 308 nodes and 384 links showcase the effectiveness and application of the proposed synthetic modeling and formulation.展开更多
Sheep and goat coccidiosis has a worldwide distribution and is an important disease on lambing farms.Infection with multiple Eimeria species can lead to severe intestinal damage in sheep/goats and economic losses on f...Sheep and goat coccidiosis has a worldwide distribution and is an important disease on lambing farms.Infection with multiple Eimeria species can lead to severe intestinal damage in sheep/goats and economic losses on farms.Disease is a serious constraint to the healthy development of small ruminant farming.Studies published on PubMed,CNKI,VIP,Wanfang and the resulting references of selected studies were included.Risk factors affecting prevalence were analyzed and stratified by geographic location and climatic variables,age,sex,feeding model,season,sample year,breeds and environment.The total prevalence of coccidia in sheep and goats reached more than 60%in most regions,in which the dominant species in sheep were mainly E.parva,E.ovinoidalis,and E.parva and E.ahsata.East China had the lowest prevalence of coccidia infection in sheep(43.24%),and the dominant species were different from those in the other regions,mainly E.bakuensis and E.gonzalezi.Southwestern China and Central China had slightly less than 40.0%goat coccidia infection,and the dominant species in goats were mainly E.arloingi,E.aligevi,E.hirci and E.ninakohlyakimovae.Sheep/goats of different ages can be infected with coccidiosis,but lambs between 1 and 3 months of age are more susceptible to the disease.When lambs become infected,the pathogen spreads rapidly throughout the herd.Spring,summer and autumn are the seasons with a high incidence of this disease.Environmental pollution may be a significant factor in the development of coccidiosis in sheep raised in large-scale housing.This study provides a comprehensive overview of the species,morphology and geographic distribution of Eimeria species in sheep and goats,summary prevalence in different regions of China,risk factors affecting prevalence,and prevention and control strategies.展开更多
The development of chassis active safety control technology has improved vehicle stability under extreme conditions.However,its cross-system and multi-functional characteristics make the controller difficult to achiev...The development of chassis active safety control technology has improved vehicle stability under extreme conditions.However,its cross-system and multi-functional characteristics make the controller difficult to achieve cooperative goals.In addition,the chassis system,which has high complexity,numerous subsystems,and strong coupling,will also lead to low computing efficiency and poor control effect of the controller.Therefore,this paper proposes a scenario-driven hybrid distributed model predictive control algorithm with variable control topology.This algorithm divides multiple stability regions based on the vehicle’s β−γ phase plane,forming a mapping relationship between the control structure and the vehicle’s state.A control input fusion mechanism within the transition domain is designed to mitigate the problems of system state oscillation and control input jitter caused by switching control structures.Then,a distributed state-space equation with state coupling and input coupling characteristics is constructed,and a weighted local agent cost function in quadratic programming is derived.Through cost coupling,local agents can coordinate global performance goals.Finally,through Simulink/CarSim joint simulation and hardware-in-the-loop(HIL)test,the proposed algorithm is validated to improve vehicle stability while ensuring trajectory tracking accuracy and has good applicability for multi-objective coordinated control.This paper combines the advantages of distributed MPC and decentralized MPC,achieving a balance between approximating the global optimal results and the solution’s efficiency.展开更多
The existing Low-Earth-Orbit(LEO)positioning performance cannot meet the requirements of Unmanned Aerial Vehicle(UAV)clusters for high-precision real-time positioning in the Global Navigation Satellite System(GNSS)den...The existing Low-Earth-Orbit(LEO)positioning performance cannot meet the requirements of Unmanned Aerial Vehicle(UAV)clusters for high-precision real-time positioning in the Global Navigation Satellite System(GNSS)denial conditions.Therefore,this paper proposes a UAV Clusters Information Geometry Fusion Positioning(UC-IGFP)method using pseudoranges from the LEO satellites.A novel graph model for linking and computing between the UAV clusters and LEO satellites was established.By utilizing probability to describe the positional states of UAVs and sensor errors,the distributed multivariate Probability Fusion Cooperative Positioning(PF-CP)algorithm is proposed to achieve high-precision cooperative positioning and integration of the cluster.Criteria to select the centroid of the cluster were set.A new Kalman filter algorithm that is suitable for UAV clusters was designed based on the global benchmark and Riemann information geometry theory,which overcomes the discontinuity problem caused by the change of cluster centroids.Finally,the UC-IGFP method achieves the LEO continuous highprecision positioning of UAV clusters.The proposed method effectively addresses the positioning challenges caused by the strong direction of signal beams from LEO satellites and the insufficient constraint quantity of information sources at the edge nodes of the cluster.It significantly improves the accuracy and reliability of LEO-UAV cluster positioning.The results of comprehensive simulation experiments show that the proposed method has a 30.5%improvement in performance over the mainstream positioning methods,with a positioning error of 14.267 m.展开更多
Dear Editor,This letter focuses on the distributed cooperative regulation problem for a class of networked re-entrant manufacturing systems(RMSs).The networked system is structured with a three-tier architecture:the p...Dear Editor,This letter focuses on the distributed cooperative regulation problem for a class of networked re-entrant manufacturing systems(RMSs).The networked system is structured with a three-tier architecture:the production line,the manufacturing layer and the workshop layer.The dynamics of re-entrant production lines are governed by hyperbolic partial differential equations(PDEs)based on the law of mass conservation.展开更多
Dear Editor,Through distributed machine learning,multi-UAV systems can achieve global optimization goals without a centralized server,such as optimal target tracking,by leveraging local calculation and communication w...Dear Editor,Through distributed machine learning,multi-UAV systems can achieve global optimization goals without a centralized server,such as optimal target tracking,by leveraging local calculation and communication with neighbors.In this work,we implement the stochastic gradient descent algorithm(SGD)distributedly to optimize tracking errors based on local state and aggregation of the neighbors'estimation.However,Byzantine agents can mislead neighbors,causing deviations from optimal tracking.We prove that the swarm achieves resilient convergence if aggregated results lie within the normal neighbors'convex hull,which can be guaranteed by the introduced centerpoint-based aggregation rule.In the given simulated scenarios,distributed learning using average,geometric median(GM),and coordinate-wise median(CM)based aggregation rules fail to track the target.Compared to solely using the centerpoint aggregation method,our approach,which combines a pre-filter with the centroid aggregation rule,significantly enhances resilience against Byzantine attacks,achieving faster convergence and smaller tracking errors.展开更多
Based on the meteorological observation data from 1994 to 2023,the spatiotemporal distribution characteristics and periodic changes of extreme precipitation were analyzed.The extreme precipitation showed a fluctuating...Based on the meteorological observation data from 1994 to 2023,the spatiotemporal distribution characteristics and periodic changes of extreme precipitation were analyzed.The extreme precipitation showed a fluctuating upward trend,and reached a peak of 713.5 mm in 2010.The frequency of events increased from 7 times in 1994-2000 to 56 times in 2020-2023,with significant periodicity of 3-4 and 7-8 a.In terms of spatial distribution,the precipitation intensity in the upper reaches was significantly higher than that in the middle and lower reaches,reaching 421.6 and 405.7 mm respectively.The lowest was in downstream Wuchuan City(268.3 mm),showing a decreasing trend from upstream to downstream.Extreme precipitation was mainly concentrated from July to October,especially in September(accounting for 25.8%).Typhoon was the main cause,with 80%of the TOP10 records related to typhoons,and the average precipitation intensity of typhoons reached 501.6 mm.The average precipitation intensity from 2020 to 2023 reached 442.8 mm.The correlation coefficient between 12-h rainfall intensity and flood level was 0.85,and the accuracy of flood warning based on rainfall intensity threshold was 78%,which had guiding significance for flood control and disaster reduction.展开更多
基金supported by the National Key R&D Program of China(grant no.2020YFA0908900)the National Natural Science Foundation of China(grant nos.22105124,22325406,21934007,21991134,T2188102)+1 种基金2022 Shanghai“Science and Technology Innovation Action Plan”Fundamental Research Project(grant no.22JC1401203)the New Cornerstone Science Foundation,and the Open Research Fund of the National Facility for Translational Medicine(Shanghai,grant no.TMSK-2021-412).
文摘The functionalization of living cells,both internally and externally,transforming them into microma-chines with specified functions,holds significant po-tential in fields such as biosensing,biocomputing,and intelligent theranostics.However,due to the complexity and dynamic nature of living cells,it remains challenging to allocate exogenous function-al materials to specific locations within the cell or on its surface and maintain their positions stable for a reasonable period.Here,we devise a DNA-pro-grammed cargo distributing system(DCD),capable of distributing functional modules to the cell mem-brane or within the cell as needed.This system includes an amphiphilic DNA structure for determin-ing the destination of the cargo and a DNA connector carried on it for recognizing the DNA-encoded cargo.We test three different morphologies of amphiphilic DNA structures and find that their efficiencies in cell surface retention and cell internalization significantly varied,enabling the distribution of nanoparticle cargos on the cell membrane and within the cell in distinct proportions.Their positions can remain sta-ble for at least 6 h.Moreover,this allocation method shows specificity,which minimizes the deployment of mismatched cargo.This method provides new tools for the modular construction of cellular micro-machines.
基金supported by the State Grid Corporation of China Science and Technology Project,grant number 52270723000900K.
文摘The new energy power generation is becoming increasingly important in the power system.Such as photovoltaic power generation has become a research hotspot,however,due to the characteristics of light radiation changes,photovoltaic power generation is unstable and random,resulting in a low utilization rate and directly affecting the stability of the power grid.To solve this problem,this paper proposes a coordinated control strategy for a newenergy power generation system with a hybrid energy storage unit based on the lithium iron phosphate-supercapacitor hybrid energy storage unit.Firstly,the variational mode decomposition algorithm is used to separate the high and low frequencies of the power signal,which is conducive to the rapid and accurate suppression of the power fluctuation of the energy storage system.Secondly,the fuzzy control algorithm is introduced to balance the power between energy storage.In this paper,the actual data is used for simulation,and the simulation results show that the strategy realizes the effective suppression of the bus voltage fluctuation and the accurate control of the internal state of the energy storage unit,effectively avoiding problems such as overshoot and over-discharge,and can significantly improve the stability of the photovoltaic power generation systemand the stability of the Direct Current bus.It is of great significance to promote the development of collaborative control technology for photovoltaic hybrid energy storage units.
基金support from Guangdong Science and Technology(20230505)Guangdong Provincial Philosophy and Social Science Planning Project(GD20SQ25)Guangdong Provincial Special Fund for Science and Technology Innovation Strategy in 2024(Cultivation of College Students’Science and Technology Innovation)(pdjh2024a391)during preparation of this manuscript.
文摘This study investigates the coordination between regional economic growth and ecological sustainability within the context of high-quality town economy development.To address the challenges of balancing economic expansion with environmental protection,a comprehensive evaluation index system is constructed,encompassing two key dimensions:regional economy and ecological environment.Using panel data from 2013 to 2022,the coupling coordination degree model is employed to quantify the interactions and synergy between these dimensions.Additionally,spatial econometric methods are applied to calculate both global and local Moran’s Index,revealing spatial clustering patterns,regional disparities,and heterogeneity.The relative development model further identifies critical factors influencing regional coordination,with a focus on the lagging development of basic infrastructure and public services.The findings demonstrate a positive temporal trend toward improved regional coordination and reduced development gaps,with a spatial pattern characterized by higher coupling degrees in eastern and central regions compared to western areas.Based on these results,this study proposes actionable strategies to enhance coordinated development,emphasizing ecological conservation,the establishment of green production and consumption systems,ecological restoration,and strengthened municipal collaboration.This revised abstract emphasizes the study’s purpose,methods,and key findings more clearly while maintaining a professional and concise tone.Finally,based on the above analysis results,the corresponding coordinated development suggestions of regional economy and ecological environment are given from the aspects of ecological environment protection measures,green production and consumption system construction,ecological environment restoration and municipal coordination.
基金supported by the National Natural Science Foundation of China(Nos.51808158,52170101,and 52200116)Tianjin Natural Science Foundation(No.23JCYBJC00640).
文摘The electrochemical corrosion of ductile pipes(DPs)in drinking water distribution systems(DWDS)has a crucial impact on cement-mortar lining(CML)failure and metal release,potentially leading to drinking water quality deterioration and posing a risk to public health.An in-situ scanning vibrating electrode technique(SVET)with micron-scale resolution,microscopic scale detection and water quality analysis were used to investigate the corrosion behavior and metal release from DPs throughout the whole CML failure process.Metal pollutants release occurred at three different stages of CML failure process,and there are potential risks of water quality deterioration exceeding the maximum allowable levels set by national standards in the partial failure stage and lining peeling stage.Furthermore,the effects of water chemistry(Cl^(−),SO_(4)^(2−),NO_(3)−,and Ca^(2+))on corrosion scale growth and iron release activity,were investigated during the CML partial failure stage.Results showed that the CML failure process in DPs was accelerated by the autocatalysis of localized corrosion.Cl^(−)was found to damage the uncorroded metal surface,while SO_(4)^(2−)mainly dissolved the corrosion scale surface,increasing iron release.Both the oxidation of NO_(3)−and selective sedimentation of Ca2+were found to enhance the stability of corrosion scales and inhibit iron release.
基金supported by the National Nature Science Foundation of China(Grant No.52302507)。
文摘The technology of electric propulsion aircraft(EPA)represents an important direction and an advanced stage in the development of aviation electrification.It is a key pathway for green development in aviation industry and can significantly enhance the energy efficiency of aircraft propulsion system.Electric motor is the most critical electromechanical energy conversion component in an aircraft electric propulsion system(EPS).High-performance electric motors,power electronic converters and EPS control form the foundation of the EPA.This paper provides an overview of the characteristics of electric motors for EPA,analyzes the inverter topologies of EPSs,and reviews ongoing EPA projects.The article highlights the latest advancements in three types of motors:superconducting motors(SCMs),permanent magnet synchronous motors(PMSMs),and induction motors(IMs).It summarizes the control system architectures of current EPA initiatives and,building on this foundation,proposes future research directions for EPSs.These include cutting-edge areas such as high-performance motors and advanced manufacturing technologies,Ga N-or Si C-based inverter integration and innovation,electric propulsion control systems,and optimization of wiring systems.
文摘Modern aircraft tend to use fuel thermal management systems to cool onboard heat sources.However,the design of heat transfer architectures for fuel thermal management systems relies on the experience of the engineers and lacks theoretical guidance.This paper proposes a concise graph representation method based on graph theory for fuel thermal management systems,which can represent all possible connections between subsystems.A generalized optimization algorithm is proposed for fuel thermal management system architecture to minimize the heat sink.This algorithm can autonomously arrange subsystems with heat production differences and efficiently utilize the architecture of the fuel heat sink.At the same time,two evaluation indices are proposed from the perspective of subsystems.These indices intuitively and clearly show that the reason for the high efficiency of heat sink utilization is the balanced and moderate cooling of each subsystem and verify the rationality of the architecture optimization method.A set of simulations are also conducted,which demonstrate that the fuel tank temperature has no effect on the performance of the architecture.This paper provides a reference for the architectural design of aircraft fuel thermal management systems.The metrics used in this paper can also be utilized to evaluate the existing architecture.
基金supported by the Natural Science Foundation of China(No.52070145,51778453).
文摘The effects of disinfectants and plasmid-based antibiotic resistance genes(ARGs)on the growth of microorganisms and the plasmid-mediated transfer of ARGs in the water and biofilm of the drinkingwater distribution system under simulated conditionswere explored.The heterotrophic plate count of the water in reactors with 0.1 mg/L NaClO and NH_(2)Cl was higher than in the control groups.Therewas no similar phenomenon in biofilm.In thewater of reactors containing NaClO,the aphA and bla geneswere lower than in the antibiotic resistant bacteria group,while both genes were higher in the water of reactors with NH_(2)Cl than in the control group.Chloramine may promote the transfer of ARGs in the water phase.Both genes in the biofilm of the reactors containing chlorine were lower than the control group.Correlation analysis between ARGs and water quality parameters revealed that the copy numbers of the aphA gene were significantly positively correlated with the copy numbers of the bla gene in water and significantly negatively correlated in biofilm(p<0.05).The results of the sequencing assay showed that bacteria in the biofilm,in the presence of disinfectant,were primarily Gram-negative.1.0 mg/L chlorine decreased the diversity of the community in the biofilm.The relative abundance of some bacteria that may undergo transfer increased in the biofilm of the reactor containing 0.1 mg/L chlorine.
基金supported by the Basic Science Center Project of the National Natural Science Foundation of China(42388102)the National Natural Science Foundation of China(42174030)+2 种基金the Special Fund of Hubei Luojia Laboratory(220100020)the Major Science and Technology Program for Hubei Province(2022AAA002)the Fundamental Research Funds for the Central Universities of China(2042022dx0001 and 2042023kfyq01)。
文摘Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.
文摘This paper introduces an optimized planning approach for integrating photovoltaic as distributed generation (PV-DG) into the radial distribution power systems, utilizing exhaustive load flow (ELF), loss sensitivity factor (LSF), genetic algorithms (GA) methods, and numerical method based on LSF. The methodology aims to determine the optimal allocation and sizing of multiple PV-DG to minimize power loss through time series power flow analysis. An approach utilizing continuous sensitivity analysis is developed and inherently leverages power flow and loss equations to compute LSF of all buses in the system towards employing a dynamic PV-DG model for more accurate results. The algorithm uses a numerical grid search method to optimize PV-DG placement in a power distribution system, focusing on minimizing system losses. It combines iterative analysis, sensitivity assessment, and comprehensive visualization to identify and present the optimal PV-DG configurations. The present-ed algorithms are verified through co-simulation framework combining MATLAB and OpenDSS to carry out analysis for 12-bus radial distribution test system. The proposed numerical method is compared with other algorithms, such as ELF, LSF methods, and Genetic Algorithms (GA). Results show that the proposed numerical method performs well in comparison with LSF and ELF solutions.
基金supported by the National Natural Science Foundation of China(Grant No.42172308)the Youth Innovation Promotion Association CAS(Grant No.2022331)the Key Research and Development Program of Hubei Province(Grant No.2022BAA036).
文摘To overcome the limitations of microscale experimental techniques and molecular dynamics(MD)simulations,a coarse-grained molecular dynamics(CGMD)method was used to simulate the wetting processes of clay aggregates.Based on the evolution of swelling stress,final dry density,water distribution,and clay arrangements under different target water contents and dry densities,a relationship between the swelling behaviors and microstructures was established.The simulated results showed that when the clay-water well depth was 300 kcal/mol,the basal spacing from CGMD was consistent with the X-ray diffraction(XRD)data.The effect of initial dry density on swelling stress was more pronounced than that of water content.The anisotropic swelling characteristics of the aggregates are related to the proportion of horizontally oriented clay mineral layers.The swelling stress was found to depend on the distribution of tactoids at the microscopic level.At lower initial dry density,the distribution of tactoids was mainly controlled by water distribution.With increase in the bound water content,the basal spacing expanded,and the swelling stresses increased.Free water dominated at higher water contents,and the particles were easily rotated,leading to a decrease in the number of large tactoids.At higher dry densities,the distances between the clay mineral layers decreased,and the movement was limited.When bound water enters the interlayers,there is a significant increase in interparticle repulsive forces,resulting in a greater number of small-sized tactoids.Eventually,a well-defined logarithmic relationship was observed between the swelling stress and the total number of tactoids.These findings contribute to a better understanding of coupled macro-micro swelling behaviors of montmorillonite-based materials,filling a study gap in clay-water interactions on a micro scale.
基金supported by the National Natural Science Foundation of China(62303273,62373226)the National Research Foundation,Singapore through the Medium Sized Center for Advanced Robotics Technology Innovation(WP2.7)
文摘Dear Editor,The letter deals with the distributed state and fault estimation of the whole physical layer for cyber-physical systems(CPSs) when the cyber layer suffers from DoS attacks. With the advancement of embedded computing, communication and related hardware technologies, CPSs have attracted extensive attention and have been widely used in power system, traffic network, refrigeration system and other fields.
基金supported in part by the National Key Research and Development Project(2023YFE0206200)the National Natural Science Foundation of China(U23B2058)+3 种基金in part by Guangdong Regional Joint Foundation Key Project(2022B1515120076)the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2025-00555463&RS-2025-25456394)the Tianjin Top Scientist Studio Project(24JRRCRC00030)the Tianjin Belt and Road Joint Laboratory(24PTLYHZ00250).
文摘Both evolutionary computation(EC)and multiagent systems(MAS)study the emergence of intelligence through the interaction and cooperation of a group of individuals.EC focuses on solving various complex optimization problems,while MAS provides a flexible model for distributed artificial intelligence.Since their group interaction mechanisms can be borrowed from each other,many studies have attempted to combine EC and MAS.With the rapid development of the Internet of Things,the confluence of EC and MAS has become more and more important,and related articles have shown a continuously growing trend during the last decades.In this survey,we first elaborate on the mutual assistance of EC and MAS from two aspects,agent-based EC and EC-assisted MAS.Agent-based EC aims to introduce characteristics of MAS into EC to improve the performance and parallelism of EC,while EC-assisted MAS aims to use EC to better solve optimization problems in MAS.Furthermore,we review studies that combine the cooperation mechanisms of EC and MAS,which greatly leverage the strengths of both sides.A description framework is built to elaborate existing studies.Promising future research directions are also discussed in conjunction with emerging technologies and real-world applications.
基金supported by the National Key Research and Development Program of China(2022YFE0114400).
文摘Toxoplasma gondii(T.gondii)is a globally distributed parasite that can infect a diversity of warm-blooded animals,including swine and humans.Infection in swine poses a considerable threat to food safety and public health.The aim of this meta-analysis was to estimate the seroprevalence of T.gondii infection in the swine population in China from 2000 to 2023 and to examine potential factors associated with infection.A total of 112 studies were included,collectively involving 145,152 swine samples originating from 26 provinces.The pooled seroprevalence was 26.0%(95%CI:23.3%–28.7%).Stratified analysis based on diagnostic methods revealed that studies using the indirect hemagglutination assay(IHA)reported a seroprevalence of 19.7%(95%CI:17.2%–22.2%),whereas those utilizing the enzyme-linked immunosorbent assay(ELISA)reported a higher seroprevalence of 35.5%(95%CI:29.1%–41.8%).Geographical analysis indicated higher seroprevalence in the South Central and Southwest regions,whereas the East and Northwest areas reported the lowest seroprevalence.Chongqing Province reported the highest seroprevalence,reaching 44.9%(95%CI:43.4%–46.0%),followed by Xinjiang,Hainan,and Guizhou,whereas the lowest was observed in Shandong Province(3.5%,95%CI:1.7%–6.1%).These findings provide important epidemiological evidence that can inform strategies for the prevention and control of T.gondii infection in swine populations,with a focus on high-risk populations and geographical areas.This imperative contributes substantially to the improvement of both food safety and public health.
文摘Resilience studies for water distribution systems(WDS)coupled with other interdependent infrastructure systems attract increasing attention from stakeholders and researchers.However,most existing large-scale WDS models are single infrastructure-based without consideration of other infrastructure systems.This is due to a lack of needed information on systems coupling,the structure of the simulator used,and the computation load involved.To address these gaps,this paper presents a synthetic modeling framework for a real-world WDS as coordinating with other infrastructure systems via a building-mediated clustering approach through consideration of physical distance and node capacity.First,the WDS network topology and operation parameters are inferred via bulk open-source information.A building-mediated clustering approach is designed to systematically derive the interdependence between the WDS and the power system similarly created as a case study.Second,a novel linearization method is developed in formulating the WDS model that can relieve computation load while maintaining accuracy.Finally,a disruption-recovery framework is developed to demonstrate the proposed methodology in modelling WDS resilience.The framework is applied to a neighborhood in Queenstown,Singapore,an area of 20.43 km^(2) and 96,000 population.The near-real-time simulations on the coupled system involving 308 nodes and 384 links showcase the effectiveness and application of the proposed synthetic modeling and formulation.
基金supported,in part,by Key Research and Development Projects of Henan,China(231111111600)the National Key R&D Program(2023YFD1801200)the China Agriculture(sheep and goats)Research System(CARS-38).
文摘Sheep and goat coccidiosis has a worldwide distribution and is an important disease on lambing farms.Infection with multiple Eimeria species can lead to severe intestinal damage in sheep/goats and economic losses on farms.Disease is a serious constraint to the healthy development of small ruminant farming.Studies published on PubMed,CNKI,VIP,Wanfang and the resulting references of selected studies were included.Risk factors affecting prevalence were analyzed and stratified by geographic location and climatic variables,age,sex,feeding model,season,sample year,breeds and environment.The total prevalence of coccidia in sheep and goats reached more than 60%in most regions,in which the dominant species in sheep were mainly E.parva,E.ovinoidalis,and E.parva and E.ahsata.East China had the lowest prevalence of coccidia infection in sheep(43.24%),and the dominant species were different from those in the other regions,mainly E.bakuensis and E.gonzalezi.Southwestern China and Central China had slightly less than 40.0%goat coccidia infection,and the dominant species in goats were mainly E.arloingi,E.aligevi,E.hirci and E.ninakohlyakimovae.Sheep/goats of different ages can be infected with coccidiosis,but lambs between 1 and 3 months of age are more susceptible to the disease.When lambs become infected,the pathogen spreads rapidly throughout the herd.Spring,summer and autumn are the seasons with a high incidence of this disease.Environmental pollution may be a significant factor in the development of coccidiosis in sheep raised in large-scale housing.This study provides a comprehensive overview of the species,morphology and geographic distribution of Eimeria species in sheep and goats,summary prevalence in different regions of China,risk factors affecting prevalence,and prevention and control strategies.
基金Supported by National Natural Science Foundation of China(Grant Nos.52225212,52272418,U22A20100)National Key Research and Development Program of China(Grant No.2022YFB2503302).
文摘The development of chassis active safety control technology has improved vehicle stability under extreme conditions.However,its cross-system and multi-functional characteristics make the controller difficult to achieve cooperative goals.In addition,the chassis system,which has high complexity,numerous subsystems,and strong coupling,will also lead to low computing efficiency and poor control effect of the controller.Therefore,this paper proposes a scenario-driven hybrid distributed model predictive control algorithm with variable control topology.This algorithm divides multiple stability regions based on the vehicle’s β−γ phase plane,forming a mapping relationship between the control structure and the vehicle’s state.A control input fusion mechanism within the transition domain is designed to mitigate the problems of system state oscillation and control input jitter caused by switching control structures.Then,a distributed state-space equation with state coupling and input coupling characteristics is constructed,and a weighted local agent cost function in quadratic programming is derived.Through cost coupling,local agents can coordinate global performance goals.Finally,through Simulink/CarSim joint simulation and hardware-in-the-loop(HIL)test,the proposed algorithm is validated to improve vehicle stability while ensuring trajectory tracking accuracy and has good applicability for multi-objective coordinated control.This paper combines the advantages of distributed MPC and decentralized MPC,achieving a balance between approximating the global optimal results and the solution’s efficiency.
基金supported in part by the National Natural Science Foundation of China(Nos.62171375,62271397,62001392,62101458,62173276,61803310 and 61801394)the Shenzhen Science and Technology Innovation ProgramChina(No.JCYJ20220530161615033)。
文摘The existing Low-Earth-Orbit(LEO)positioning performance cannot meet the requirements of Unmanned Aerial Vehicle(UAV)clusters for high-precision real-time positioning in the Global Navigation Satellite System(GNSS)denial conditions.Therefore,this paper proposes a UAV Clusters Information Geometry Fusion Positioning(UC-IGFP)method using pseudoranges from the LEO satellites.A novel graph model for linking and computing between the UAV clusters and LEO satellites was established.By utilizing probability to describe the positional states of UAVs and sensor errors,the distributed multivariate Probability Fusion Cooperative Positioning(PF-CP)algorithm is proposed to achieve high-precision cooperative positioning and integration of the cluster.Criteria to select the centroid of the cluster were set.A new Kalman filter algorithm that is suitable for UAV clusters was designed based on the global benchmark and Riemann information geometry theory,which overcomes the discontinuity problem caused by the change of cluster centroids.Finally,the UC-IGFP method achieves the LEO continuous highprecision positioning of UAV clusters.The proposed method effectively addresses the positioning challenges caused by the strong direction of signal beams from LEO satellites and the insufficient constraint quantity of information sources at the edge nodes of the cluster.It significantly improves the accuracy and reliability of LEO-UAV cluster positioning.The results of comprehensive simulation experiments show that the proposed method has a 30.5%improvement in performance over the mainstream positioning methods,with a positioning error of 14.267 m.
文摘Dear Editor,This letter focuses on the distributed cooperative regulation problem for a class of networked re-entrant manufacturing systems(RMSs).The networked system is structured with a three-tier architecture:the production line,the manufacturing layer and the workshop layer.The dynamics of re-entrant production lines are governed by hyperbolic partial differential equations(PDEs)based on the law of mass conservation.
基金supported By Guangdong Major Project of Basic and Applied Basic Research(2023B0303000009)Guangdong Basic and Applied Basic Research Foundation(2024A1515030153,2025A1515011587)+1 种基金Project of Department of Education of Guangdong Province(2023ZDZX4046)Shen-zhen Natural Science Fund(Stable Support Plan Program 20231122121608001),Ningbo Municipal Science and Technology Bureau(ZX2024000604).
文摘Dear Editor,Through distributed machine learning,multi-UAV systems can achieve global optimization goals without a centralized server,such as optimal target tracking,by leveraging local calculation and communication with neighbors.In this work,we implement the stochastic gradient descent algorithm(SGD)distributedly to optimize tracking errors based on local state and aggregation of the neighbors'estimation.However,Byzantine agents can mislead neighbors,causing deviations from optimal tracking.We prove that the swarm achieves resilient convergence if aggregated results lie within the normal neighbors'convex hull,which can be guaranteed by the introduced centerpoint-based aggregation rule.In the given simulated scenarios,distributed learning using average,geometric median(GM),and coordinate-wise median(CM)based aggregation rules fail to track the target.Compared to solely using the centerpoint aggregation method,our approach,which combines a pre-filter with the centroid aggregation rule,significantly enhances resilience against Byzantine attacks,achieving faster convergence and smaller tracking errors.
文摘Based on the meteorological observation data from 1994 to 2023,the spatiotemporal distribution characteristics and periodic changes of extreme precipitation were analyzed.The extreme precipitation showed a fluctuating upward trend,and reached a peak of 713.5 mm in 2010.The frequency of events increased from 7 times in 1994-2000 to 56 times in 2020-2023,with significant periodicity of 3-4 and 7-8 a.In terms of spatial distribution,the precipitation intensity in the upper reaches was significantly higher than that in the middle and lower reaches,reaching 421.6 and 405.7 mm respectively.The lowest was in downstream Wuchuan City(268.3 mm),showing a decreasing trend from upstream to downstream.Extreme precipitation was mainly concentrated from July to October,especially in September(accounting for 25.8%).Typhoon was the main cause,with 80%of the TOP10 records related to typhoons,and the average precipitation intensity of typhoons reached 501.6 mm.The average precipitation intensity from 2020 to 2023 reached 442.8 mm.The correlation coefficient between 12-h rainfall intensity and flood level was 0.85,and the accuracy of flood warning based on rainfall intensity threshold was 78%,which had guiding significance for flood control and disaster reduction.
