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Modeling of Precipitation over Africa:Progress,Challenges,and Prospects
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作者 A.A.AKINSANOLA C.N.WENHAJI +21 位作者 R.BARIMALALA P.-A.MONERIE R.D.DIXON A.T.TAMOFFO M.O.ADENIYI V.ONGOMA I.DIALLO M.GUDOSHAVA C.M.WAINWRIGHT R.JAMES K.C.SILVERIO A.FAYE S.S.NANGOMBE M.W.POKAM D.A.VONDOU N.C.G.HART I.PINTO M.KILAVI S.HAGOS E.N.RAJAGOPAL R.K.KOLLI S.JOSEPH 《Advances in Atmospheric Sciences》 2026年第1期59-86,共28页
In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and cha... In recent years,there has been an increasing need for climate information across diverse sectors of society.This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and change.Likewise,this period has seen a significant increase in our understanding of the physical processes and mechanisms that drive precipitation and its variability across different regions of Africa.By leveraging a large volume of climate model outputs,numerous studies have investigated the model representation of African precipitation as well as underlying physical processes.These studies have assessed whether the physical processes are well depicted and whether the models are fit for informing mitigation and adaptation strategies.This paper provides a review of the progress in precipitation simulation overAfrica in state-of-the-science climate models and discusses the major issues and challenges that remain. 展开更多
关键词 RAINFALL MONSOON climate modeling CORDEX CMIP6 convection-permitting models
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基于ECO-ABM模型的互花米草种子漂移扩散数值模拟研究
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作者 吴亚楠 卢梦瑶 +3 位作者 于兴晨 王志勇 杨鉴宇 王磊 《海洋科学》 北大核心 2025年第5期24-33,共10页
本文利用MIKE21二维水动力模型重构水动力场,综合考虑互花米草种子物理特性参数,采用代理建模技术(Agent Based Modelling,ABM)构建表征互花米草种子运动特征的模型(ECO-ABM),以山东滨州套尔河河口至潮河河口之间互花米草分布海域为研... 本文利用MIKE21二维水动力模型重构水动力场,综合考虑互花米草种子物理特性参数,采用代理建模技术(Agent Based Modelling,ABM)构建表征互花米草种子运动特征的模型(ECO-ABM),以山东滨州套尔河河口至潮河河口之间互花米草分布海域为研究对象开展案例实证,研究该海域12个互花米草分布区块种子远距离扩散能力和各区块间相互迁移关系。经实测数据验证,模拟潮位、流速和流向平均绝对误差最大分别为−8.23 cm、−11.69 cm/s和−21.35°,水动力模型可较为真实的反映水动力条件。ECO-ABM模型实证结果表明,区块1、3、8、10内种子在启动流速为0.01~0.15 m/s时的迁出概率平均值分别为90%、70%、55%、45%,最大迁移距离分别为38.7 km、49.4 km、32.1 km和16.8 km,反映出潮汐潮流水动力条件、水深地形和种子自身物理特性对其漂移扩散具有重要影响;在远距离扩散方面,研究海域种子沿岸向东至莱州湾扩散的趋势明显,沿岸至少存在2个潜在高风险区域;多个区块间存在种子相互迁移关系,尤其是区块5、8、10—12间,从种子有性繁殖角度推测区块5和8可能为该区域互花米草暴发繁殖的源头。研究结果可为渤海湾有效防治互花米草提供科学参考,研究方法具有区域拓展适用价值。 展开更多
关键词 互花米草种子 漂移扩散 Agent Based Modelling(abm) 数值模拟
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智能体仿真模拟(ABM)的异化风险与融合治理——基于《科技伦理审查办法(试行)》的适用展开
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作者 翁春露 《中国科技论坛》 北大核心 2026年第1期11-19,共9页
智能体仿真模拟(ABM)旨在通过模拟出的智能体及其互动样态展现人类社会的复杂运行态势,其运行逻辑遵循“环境—个体—群体—社会”四重模拟,即智能体环境的现实刻画、智能体个体的属性设置、智能体群体的行为互动、智能体社会的涌现机... 智能体仿真模拟(ABM)旨在通过模拟出的智能体及其互动样态展现人类社会的复杂运行态势,其运行逻辑遵循“环境—个体—群体—社会”四重模拟,即智能体环境的现实刻画、智能体个体的属性设置、智能体群体的行为互动、智能体社会的涌现机制。在人工智能加持下,快速发展的ABM具有传染性异化风险,“环境—个体—群体—社会”任一行为链条的偏差会相互影响直至出现整体性偏差,导致ABM模拟出的智能体及其互动样态无法正确反映人类社会现实情形,将ABM运用到现实生活中指导社会实践,则会催生违背人类价值、破坏社会秩序的行为。基于法律主导与伦理先行的融合治理模式,通过科技伦理审查制度明确ABM科技伦理审查的主体、对象与程序,以此对ABM的传染性异化风险进行有效规制。 展开更多
关键词 智能体仿真模拟 智能体 传染性异化 融合治理 科技伦理审查
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数字场域下食品直播电商质量诚信治理——基于价值分配与消费维权的ABM仿真
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作者 郑小平 赵沐天 《四川农业大学学报》 北大核心 2025年第6期1464-1472,共9页
【目的】食品直播电商市场高速扩张中质量诚信危机凸显,根源在于数字场域内经济资本价值分配失衡与消费维权社会资本缺位,需要系统优化治理。【方法】运用基于主体建模方法,构建“价值分配—消费维权”治理框架进行仿真研究。【结果】... 【目的】食品直播电商市场高速扩张中质量诚信危机凸显,根源在于数字场域内经济资本价值分配失衡与消费维权社会资本缺位,需要系统优化治理。【方法】运用基于主体建模方法,构建“价值分配—消费维权”治理框架进行仿真研究。【结果】实施单一价值分配措施效果有限,而组合失信违约惩戒和维权激励机制可促进质量诚信治理。提升维权赔付力度对诚信治理长期有效,而消费维权社会影响力在短期内有效。经济资本价值分配和消费维权社会资本双轮驱动治理效果显著。【结论】应协同运转失信惩戒和维权激励价值分配机制,实现消费维权治理的长短期措施有机衔接,经济和社会资本共同参与食品电商质量诚信治理。 展开更多
关键词 数字场域 食品直播电商 质量诚信 场域资本 基于主体建模(abm)
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基于ABMS的无人两栖作战车系统需求分析与仿真
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作者 孙雪 王东辉 +2 位作者 占正勇 刘文金 崔玉伟 《兵工自动化》 北大核心 2025年第5期101-106,共6页
针对未来战争对无人系统的需求不断增加,提出一种适用于狭小空间和复杂环境的新型无人系统——两栖无人作战车系统,同时具备地面行驶、墙面爬行、空中飞行和协同作战能力。采用基于Agent的建模与仿真(agent-based modeling and simulati... 针对未来战争对无人系统的需求不断增加,提出一种适用于狭小空间和复杂环境的新型无人系统——两栖无人作战车系统,同时具备地面行驶、墙面爬行、空中飞行和协同作战能力。采用基于Agent的建模与仿真(agent-based modeling and simulation,ABMS)方法,在分析其应用任务场景的基础上,通过构造任务场景、桌面模型、仿真验证,深入分析两栖无人作战车系统应具备的功能,并根据分析结果提出所需解决的关键技术。结果表明:该系统对扩展无人系统任务环境、提升自主作战能力有着重要意义。 展开更多
关键词 无人系统 任务场景 abmS方法 仿真推演
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Influence of testbed characteristics on community resilience using agent-based modeling
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作者 Xu Han Maria Koliou 《Resilient Cities and Structures》 2025年第2期69-83,共15页
There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes.Given the significant damage incurred by tornadoes upon communities,community resilience analyses for tornado-stricken com... There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes.Given the significant damage incurred by tornadoes upon communities,community resilience analyses for tornado-stricken communities have been gaining momentum.As the community resilience analysis aims to guide how to lay out effective hazard mitigation strategies to decrease damage and improve recovery,a comprehensive and accurate approach is necessary.Agent-based modeling,an analysis approach in which different types of agents are created with their properties and behavior clearly defined to simulate the processes of those agents in an external environ-ment,is the most comprehensive and accurate approach so far to conducting community resilience simulations and investigating the decision-making for mitigation and recovery under natural hazards.In this paper,agent-based models(ABMs)are created to simulate the recovery process of a virtual testbed based on the real-world community in Joplin City,MO.The tornado path associated with the real-world tornado event that occurred in May 2011 is adopted in the tornado hazard modeling for the Joplin testbed.In addition,agent-based models are created for another virtual community in the Midwest United States named Centerville using an assumed tornado scenario of the same EF-scale as that in Joplin.The effects of hazard mitigation strategies on the two communities are also explored.A comparison between the analysis results of these two testbeds can indicate the influence of the characteristics of a tornado-prone community on the resilience of the community as well as on the effects of hazard mitigation strategies.It is observed that a community’s level of development significantly impacts the tornado resilience.In addition,the effects of a specific type of hazard mitigation strategy on the recovery process are contingent upon testbed characteristics. 展开更多
关键词 Community resilience agent-based model(abm) TORNADO Hazard mitigation strategy Testbed characteristics
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Evolution of Smart Parks and Development of Park Information Modeling(PIM):Concept and Design Application 被引量:2
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作者 YANG Kaixian ZHEN Feng ZHANG Shanqi 《Chinese Geographical Science》 2025年第5期982-998,共17页
With the development of smart cities and smart technologies,parks,as functional units of the city,are facing smart transformation.The development of smart parks can help address challenges of technology integration wi... With the development of smart cities and smart technologies,parks,as functional units of the city,are facing smart transformation.The development of smart parks can help address challenges of technology integration within urban spaces and serve as testbeds for exploring smart city planning and governance models.Information models facilitate the effective integration of technology into space.Building Information Modeling(BIM)and City Information Modeling(CIM)have been widely used in urban construction.However,the existing information models have limitations in the application of the park,so it is necessary to develop an information model suitable for the park.This paper first traces the evolution of park smart transformation,reviews the global landscape of smart park development,and identifies key trends and persistent challenges.Addressing the particularities of parks,the concept of Park Information Modeling(PIM)is proposed.PIM leverages smart technologies such as artificial intelligence,digital twins,and collaborative sensing to help form a‘space-technology-system’smart structure,enabling systematic management of diverse park spaces,addressing the deficiency in park-level information models,and aiming to achieve scale articulation between BIM and CIM.Finally,through a detailed top-level design application case study of the Nanjing Smart Education Park in China,this paper illustrates the translation process of the PIM concept into practice,showcasing its potential to provide smart management tools for park managers and enhance services for park stakeholders,although further empirical validation is required. 展开更多
关键词 smart park smart city Park Information modeling(PIM) smart technology Building Information modeling(BIM) City Information modeling(CIM)
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Using Agent-Based Modeling to Study the Adaptation and Evolution of Human Emotions and Cognition
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作者 Duan Qin Luo Siyang 《心理科学》 北大核心 2025年第6期1314-1332,共19页
This review explores the use of agent-based modeling(ABM)within the framework of study human emotion and cognition in the context of its ability to simulate complex social interactions,adaptive changes,and evolutionar... This review explores the use of agent-based modeling(ABM)within the framework of study human emotion and cognition in the context of its ability to simulate complex social interactions,adaptive changes,and evolutionary processes.By representing agents and their defined environments with probabilistic interactions,ABM allows the assessment of the effects of individual behavior at the micro level on the greater social phenomena at the macro level.The review looks into the applications of ABM in portraying some of the key components of emotions and cognition-empathy,cooperation,decision making,and emotional transmission-and analyzes the problems including scalability,empirical validation,and description of sensitive emotional states.The most important conclusion is that merging ABM with information neurobiological data and artificial intelligence(AI)techniques would allow for deepening the interactions within the system and enhancing its responsiveness to stimuli.This review highlights approaches that aim to exploit the ABM methodology more fully and integrates methods from biology,neuroscience,and engineering.This integration could contribute to our understanding of the human behavior evolution and adaptation within systems relevant to policymaking,healthcare,and education. 展开更多
关键词 agent-based modeling emotions evolution cognition evolution social interactions
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A Multi-Level Semantic Constraint Approach for Highway Tunnel Scene Twin Modeling 被引量:1
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作者 LI Yufei XIE Yakun +3 位作者 CHEN Mingzhen ZHAO Yaoji TU Jiaxing HU Ya 《Journal of Geodesy and Geoinformation Science》 2025年第2期37-56,共20页
As a key node of modern transportation network,the informationization management of road tunnels is crucial to ensure the operation safety and traffic efficiency.However,the existing tunnel vehicle modeling methods ge... As a key node of modern transportation network,the informationization management of road tunnels is crucial to ensure the operation safety and traffic efficiency.However,the existing tunnel vehicle modeling methods generally have problems such as insufficient 3D scene description capability and low dynamic update efficiency,which are difficult to meet the demand of real-time accurate management.For this reason,this paper proposes a vehicle twin modeling method for road tunnels.This approach starts from the actual management needs,and supports multi-level dynamic modeling from vehicle type,size to color by constructing a vehicle model library that can be flexibly invoked;at the same time,semantic constraint rules with geometric layout,behavioral attributes,and spatial relationships are designed to ensure that the virtual model matches with the real model with a high degree of similarity;ultimately,the prototype system is constructed and the case region is selected for the case study,and the dynamic vehicle status in the tunnel is realized by integrating real-time monitoring data with semantic constraints for precise virtual-real mapping.Finally,the prototype system is constructed and case experiments are conducted in selected case areas,which are combined with real-time monitoring data to realize dynamic updating and three-dimensional visualization of vehicle states in tunnels.The experiments show that the proposed method can run smoothly with an average rendering efficiency of 17.70 ms while guaranteeing the modeling accuracy(composite similarity of 0.867),which significantly improves the real-time and intuitive tunnel management.The research results provide reliable technical support for intelligent operation and emergency response of road tunnels,and offer new ideas for digital twin modeling of complex scenes. 展开更多
关键词 highway tunnel twin modeling multi-level semantic constraints tunnel vehicles multidimensional modeling
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Solubility and Thermodynamic Modeling of 3⁃Nitro⁃1,2,4⁃triazole⁃5⁃one(NTO)in Different Binary Solvents 被引量:1
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作者 GUO Hao-qi YANG Yu-lin 《含能材料》 北大核心 2025年第3期295-303,共9页
Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging f... Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ). 展开更多
关键词 3-nitro-l 2 4-triazole-5-one(NTO) SOLUBILITY thermodynamic models apparent thermodynamic analysis
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Candida albicans and colorectal cancer:A paradoxical role revealed through metabolite profiling and prognostic modeling 被引量:2
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作者 Hao-Ling Zhang Rui Zhao +8 位作者 Di Wang Siti Nurfatimah Mohd Sapudin Badrul Hisham Yahaya Mohammad Syamsul Reza Harun Zhong-Wen Zhang Zhi-Jing Song Yan-Ting Liu Sandai Doblin Ping Lu 《World Journal of Clinical Oncology》 2025年第4期195-279,共85页
BACKGROUND Emerging evidence implicates Candida albicans(C.albicans)in human oncogenesis.Notably,studies have supported its involvement in regulating outcomes in colorectal cancer(CRC).This study investigated the para... BACKGROUND Emerging evidence implicates Candida albicans(C.albicans)in human oncogenesis.Notably,studies have supported its involvement in regulating outcomes in colorectal cancer(CRC).This study investigated the paradoxical role of C.albicans in CRC,aiming to determine whether it promotes or suppresses tumor development,with a focus on the mechanistic basis linked to its metabolic profile.AIM To investigate the dual role of C.albicans in the development and progression of CRC through metabolite profiling and to establish a prognostic model that integrates the microbial and metabolic interactions in CRC,providing insights into potential therapeutic strategies and clinical outcomes.METHODSA prognostic model integrating C. albicans with CRC was developed, incorporating enrichment analysis, immuneinfiltration profiling, survival analysis, Mendelian randomization, single-cell sequencing, and spatial transcriptomics.The effects of the C. albicans metabolite mixture on CRC cells were subsequently validated in vitro. Theprimary metabolite composition was characterized using liquid chromatography-mass spectrometry.RESULTSA prognostic model based on five specific mRNA markers, EHD4, LIME1, GADD45B, TIMP1, and FDFT1, wasestablished. The C. albicans metabolite mixture significantly reduced CRC cell viability. Post-treatment analysisrevealed a significant decrease in gene expression in HT29 cells, while the expression levels of TIMP1, EHD4, andGADD45B were significantly elevated in HCT116 cells. Conversely, LIME1 expression and that of other CRC celllines showed reductions. In normal colonic epithelial cells (NCM460), GADD45B, TIMP1, and FDFT1 expressionlevels were significantly increased, while LIME1 and EHD4 levels were markedly reduced. Following metabolitetreatment, the invasive and migratory capabilities of NCM460, HT29, and HCT116 cells were reduced. Quantitativeanalysis of extracellular ATP post-treatment showed a significant elevation (P < 0.01). The C. albicans metabolitemixture had no effect on reactive oxygen species accumulation in CRC cells but led to a reduction in mitochondrialmembrane potential, increased intracellular lipid peroxidation, and induced apoptosis. Metabolomic profilingrevealed significant alterations, with 516 metabolites upregulated and 531 downregulated.CONCLUSIONThis study introduced a novel prognostic model for CRC risk assessment. The findings suggested that the C.albicans metabolite mixture exerted an inhibitory effect on CRC initiation. 展开更多
关键词 Candida albicans Colorectal cancer Metabolic characteristics Extracellular ATP Prognostic model
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Influence of different data selection criteria on internal geomagnetic field modeling 被引量:4
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作者 HongBo Yao JuYuan Xu +3 位作者 Yi Jiang Qing Yan Liang Yin PengFei Liu 《Earth and Planetary Physics》 2025年第3期541-549,共9页
Earth’s internal core and crustal magnetic fields,as measured by geomagnetic satellites like MSS-1(Macao Science Satellite-1)and Swarm,are vital for understanding core dynamics and tectonic evolution.To model these i... Earth’s internal core and crustal magnetic fields,as measured by geomagnetic satellites like MSS-1(Macao Science Satellite-1)and Swarm,are vital for understanding core dynamics and tectonic evolution.To model these internal magnetic fields accurately,data selection based on specific criteria is often employed to minimize the influence of rapidly changing current systems in the ionosphere and magnetosphere.However,the quantitative impact of various data selection criteria on internal geomagnetic field modeling is not well understood.This study aims to address this issue and provide a reference for constructing and applying geomagnetic field models.First,we collect the latest MSS-1 and Swarm satellite magnetic data and summarize widely used data selection criteria in geomagnetic field modeling.Second,we briefly describe the method to co-estimate the core,crustal,and large-scale magnetospheric fields using satellite magnetic data.Finally,we conduct a series of field modeling experiments with different data selection criteria to quantitatively estimate their influence.Our numerical experiments confirm that without selecting data from dark regions and geomagnetically quiet times,the resulting internal field differences at the Earth’s surface can range from tens to hundreds of nanotesla(nT).Additionally,we find that the uncertainties introduced into field models by different data selection criteria are significantly larger than the measurement accuracy of modern geomagnetic satellites.These uncertainties should be considered when utilizing constructed magnetic field models for scientific research and applications. 展开更多
关键词 Macao Science Satellite-1 SWARM geomagnetic field modeling data selection core field crustal field
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基于ABM节水模型的青岛城镇生活需水水价政策仿真分析
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作者 王好芳 张祎珂 +3 位作者 代晨洋 陈怡馨 贠汝安 李典基 《水利经济》 北大核心 2025年第4期74-82,共9页
为揭示居民收入水平、水价、节水意识等关键因素对城镇居民用水行为和需水的差异化影响,根据青岛城镇居民生活节水途径和目的,将生活节水分为器具性经济节水、器具性环保节水、习惯性经济节水和习惯性环保节水4种类型,并制定了相应的行... 为揭示居民收入水平、水价、节水意识等关键因素对城镇居民用水行为和需水的差异化影响,根据青岛城镇居民生活节水途径和目的,将生活节水分为器具性经济节水、器具性环保节水、习惯性经济节水和习惯性环保节水4种类型,并制定了相应的行为规则。利用主体建模法(ABM)构建了青岛城镇居民ABM生活节水模型,该模型包含了1个政府Agent和247个城镇居民家庭Agents,在此基础上构建了青岛市城镇居民生活需水预测模型,并利用2019—2022年的青岛市城镇生活用水量对模型进行了验证,确定了模型参数,并设置了5种水价情景对青岛市2023—2035年城镇生活需水进行预测模拟。结果表明:2023—2035年青岛市城镇居民生活需水量逐年递增,但增长率逐年降低;同一规划年,随着水价的上涨,节水量逐渐加大,需水量呈减少态势,水价的提高对城镇居民节水起到促进作用,特别是对习惯性节水的影响更显著。 展开更多
关键词 主体建模法 节水 生活需水 水价政策 青岛市
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3D crustal density modeling of Egypt using GOCE satellite gravity data and seismic integration 被引量:1
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作者 Moataz Sayed Mohamed Sobh +2 位作者 Salah Saleh Amal Othman Ahmed Elmahmoudi 《Earthquake Science》 2025年第2期110-125,共16页
A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques inclu... A 3D crustal model was constructed using a combination of cutting-edge techniques,which were integrated to provide a density model for Egypt and address the sporadic distribution of seismic data.These techniques include obtaining gravity data from the Gravity Field and Steady-State Ocean Circulation Explorer(GOCE),creating seismic profiles,analyzing the receiver functions of seismic data,obtaining information from boreholes,and providing geological interpretations.GOCE satellite gravity data were processed to construct a preliminary model based on nonlinear inversions of the data.A regional crustal thickness model was developed using receiver functions,seismic refraction profiles,and geological insights.The inverted model was validated using borehole data and compared with seismic estimates.The model exhibited strong consistency and revealed a correlation between crustal thickness,geology,and tectonics of Egypt.It showed that the shallowest depths of the Moho are located in the north along the Mediterranean Sea and in the eastern part along the Red Sea,reflecting an oceanic plate with a thin,high-density crust.The deepest Moho depths are located in the southwestern part of Egypt,Red Sea coastal mountains,and Sinai Peninsula.The obtained 3D model of crustal thickness provided finely detailed Moho depth estimates that aligned closely with geology and tectonic characteristics of Egypt,contributing valuable insights into the subsurface structure and tectonic processes of region. 展开更多
关键词 GOCE satellite gravity Moho depth crustal modeling gravity inversion
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Phase field modeling of the aspect ratio dependent functional properties of NiTi shape memory alloys with different grain sizes 被引量:1
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作者 Bo Xu Beihai Huang +1 位作者 Chong Wang Qingyuan Wang 《Acta Mechanica Sinica》 2025年第1期22-41,共20页
It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size... It is well known that coarse-grained super-elastic NiTi shape memory alloys(SMAs)exhibit localized rather than homogeneous martensite transformation(MT),which,however,can be strongly influenced by either internal size(grain size,GS)or the external size(geometric size).The coupled effect of GS and geometric size on the functional properties has not been clearly understood yet.In this work,the super-elasticity,one-way,and stress-assisted two-way shape memory effects of the polycrystalline NiTi SMAs with different aspect ratios(length/width for the gauge section)and different GSs are investigated based on the phase field method.The coupled effect of the aspect ratio and GS on the functional properties is adequately revealed.The simulated results indicate that when the aspect ratio is lower than about 4:1,the stress biaxiality and stress heterogeneity in the gauge section of the sample become more and more obvious with decreasing the aspect ratio,which can significantly influence the microstructure evolution in the process involving external stress.Therefore,the corresponding functional property is strongly dependent on the aspect ratio.With decreasing the GS and the aspect ratio(to be lower than 4:1),both the aspect ratio and GS can affect the MT or martensite reorientation in each grain and the interaction among grains.Thus,due to the strong internal constraint(i.e.,the constraint of grain boundary)and the external constraint(i.e.,the constraint of geometric boundary),the capabilities of the functional properties of NiTi SMAs are gradually weakened and highly dependent on these two factors. 展开更多
关键词 Phase field modeling NITI Aspect ratio Grain size Functional property
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Modeling and sliding mode control based on inverse compensation of piezo-positioning system
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作者 LI Zhi-bin XIN Yuan-ze +1 位作者 ZHANG Jian-qiang SUN Chong-shang 《中国光学(中英文)》 北大核心 2025年第1期170-185,共16页
In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis... In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis nonlinear characteristics of piezo-positioning actuator.The static nonlinear part and dynamic linear part of the Hammerstein model are represented by models obtained through the Prandtl-Ishlinskii(PI)model and Hankel matrix system identification method,respectively.This model demonstrates good generalization capability for typical input frequencies below 200 Hz.A sliding mode inverse compensation tracking control strategy based on P-I inverse model and integral augmentation is proposed.Experimental results show that compared with PID inverse compensation control and sliding mode control without inverse compensation,the sliding mode inverse compensation control has a more ideal step response and no overshoot,moreover,the settling time is only 6.2 ms.In the frequency domain,the system closed-loop tracking bandwidth reaches 119.9 Hz,and the disturbance rejection bandwidth reaches 86.2 Hz.The proposed control strategy can effectively compensate the hysteresis nonlinearity,and improve the tracking accuracy and antidisturbance capability of piezo-positioning system. 展开更多
关键词 piezo-positioning system hysteresis nonlinearity Hammerstein model Prandtl-Ishlinskii(P-I)model system identification sliding mode control
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Millimeter-wave modeling based on transformer model for InP high electron mobility transistor
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作者 ZHANG Ya-Xue ZHANG Ao GAO Jian-Jun 《红外与毫米波学报》 北大核心 2025年第4期534-539,共6页
In this paper,the small-signal modeling of the Indium Phosphide High Electron Mobility Transistor(InP HEMT)based on the Transformer neural network model is investigated.The AC S-parameters of the HEMT device are train... In this paper,the small-signal modeling of the Indium Phosphide High Electron Mobility Transistor(InP HEMT)based on the Transformer neural network model is investigated.The AC S-parameters of the HEMT device are trained and validated using the Transformer model.In the proposed model,the eight-layer transformer encoders are connected in series and the encoder layer of each Transformer consists of the multi-head attention layer and the feed-forward neural network layer.The experimental results show that the measured and modeled S-parameters of the HEMT device match well in the frequency range of 0.5-40 GHz,with the errors versus frequency less than 1%.Compared with other models,good accuracy can be achieved to verify the effectiveness of the proposed model. 展开更多
关键词 transformer model neural network high electron mobility transistor(HEMT) small signal model
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Cumulative thermal coupling modeling and analysisof oil-immersed motor-pump assembly forelectro–hydrostatic actuator 被引量:1
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作者 Siming FAN Shaoping WANG +3 位作者 Qiyang WANG Xingjian WANG Di LIU Xiao WU 《Chinese Journal of Aeronautics》 2025年第5期394-410,共17页
The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the ... The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the compact integration of the OMP presents challenges inefficiently dissipating internal heat,leading to a performance degradation of the EHA due to ele-vated temperatures.Therefore,accurately modeling and predicting the internal thermal dynamicsof the OMP hold considerable significance for monitoring the operational condition of the EHA.In view of this,a modeling method considering cumulative thermal coupling was hereby proposed.Based on the proposed method,the thermal models of the motor and the pump were established,taking into account heat accumulation and transfer.Taking the leakage oil as the heat couplingpoint between the motor and the pump,the dynamic thermal coupling model of the OMP wasdeveloped,with the thermal characteristics of the oil considered.Additionally,the comparativeexperiments were conducted to illustrate the efficiency of the proposed model.The experimentalresults demonstrate that the proposed dynamic thermal coupling model accurately captured thethermal behavior of OMP,outperforming the static thermal parameter model.Overall,thisadvancement is crucial for effectively monitoring the health of EHA and ensuring flight safety. 展开更多
关键词 Electro-hydrostatic actuator Oil-immersed motor-pump Dynamic thermal coupling model Heat transfer Heat accumulation
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A Nonspherical Cloud Scattering Database Using Aggregates of Roughened Bullet Rosettes Model for the Advanced Radiative Transfer Modeling System(ARMS) 被引量:1
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作者 Ziyue HUANG Hanyu LU +4 位作者 Ziqiang MA Yining SHI Yang HAN Hao HU Jun YANG 《Advances in Atmospheric Sciences》 2025年第7期1483-1498,共16页
Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up ... Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table. 展开更多
关键词 nonspherical particles scattering look-up table discrete dipole approximation Advanced Radiative Transfer modeling System
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Undrained mechanical behavior of unsaturated completely weathered granite:Experimental investigation and constitutive modeling 被引量:1
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作者 DU Shao-hua MA Jin-yin +2 位作者 RUAN Bo WU Gen-shui ZHANG Rui-chao 《Journal of Central South University》 2025年第6期2307-2327,共21页
The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique natu... The undrained mechanical behavior of unsaturated completely weathered granite(CWG)is highly susceptible to alterations in the hydraulic environment,particularly under uniaxial loading conditions,due to the unique nature of this soil type.In this study,a series of unconfined compression tests were carried out on unsaturated CWG soil in an underground engineering site,and the effects of varying the environmental variables on the main undrained mechanical properties were analyzed.Based on the experimental results,a novel constitutive model was then established using the damage mechanics theory and the undetermined coefficient method.The results demonstrate that the curves of remolded CWG specimens with different moisture contents and dry densities exhibited diverse characteristics,including brittleness,significant softening,and ductility.As a typical indicator,the unconfined compression strength of soil specimens initially increased with an increase in moisture content and then decreased.Meanwhile,an optimal moisture content of approximately 10.5%could be observed,while a critical moisture content value of 13.0%was identified,beyond which the strength of the specimen decreases sharply.Moreover,the deformation and fracture of CWG specimens were predominantly caused by shear failure,and the ultimate failure modes were primarily influenced by moisture content rather than dry density.Furthermore,by comparing several similar models and the experimental data,the proposed model could accurately replicate the undrained mechanical characteristics of unsaturated CWG soil,and quantitatively describe the key mechanical indexes.These findings offer a valuable reference point for understanding the underlying mechanisms,anticipating potential risks,and implementing effective control measures in similar underground engineering projects. 展开更多
关键词 completely weathered granite undrained mechanical behavior environmental variable unconfined compression test constitutive model
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