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Aspect in Topography to Enhance Fine-detailed Landform Element Extraction on High-resolution DEM
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作者 XIE Xiao ZHOU Xiran +4 位作者 XUE Bing XUE Yong QIN Kai LI Jingzhong YANG Jun 《Chinese Geographical Science》 SCIE CSCD 2021年第5期915-930,共16页
The value of the high-resolution data lies in the high-precision information discovery.The fine-detailed landform element extraction is thus the basis of high-fidelity application of the high-resolution digital elevat... The value of the high-resolution data lies in the high-precision information discovery.The fine-detailed landform element extraction is thus the basis of high-fidelity application of the high-resolution digital elevation models(DEMs).However,the results of landform element extraction generated by classical methods might be ungrounded on high-resolution DEMs.This paper presents our research on using the aspect to reinforce the applicability and robustness of the classical approaches in landform element extraction.First,according to the research of pattern recognition,we assume that aspect-enhanced landform representation is robust to rotation,scaling and affine variance.To testify the role of aspect,we respectively integrated the aspect into three classical approaches:mean curvaturebased fuzzy classification,elevation-based feature descriptor,and object-based segmentation.In the experiment,based on four types of high-resolution DEMs(1 m,2 m,4 m and 8 m),we compare each classical approaches and their corresponding aspect-enhanced approaches based on extracting the rims of two craters having different landforms,and the ridgelines and valleylines of a region covered by few vegetables and man-made buildings.In comparison to the results generated by curvature-based fuzzy classification,the aspect enhanced curvature-based fuzzy classification can effectively filter a number of noises outperforms the curvature-based one.Otherwise,the aspect-enhanced feature descriptor can detect more landform elements than the elevation-based feature descriptor.Moreover,the aspect-based segmentation can detect the main structure of landform,while the boundaries segmented by classical approaches are messing and meaningless.The systematic experiments on meter-level resolution DEMs proved that the aspect in topography could effectively to improve the classical method-system,including fuzzy-based classification,feature descriptors-based detection and object-based segmentation.The value of aspect is significantly great to be worthy of attentions in landform representation. 展开更多
关键词 high-resolution dem(digital elevation model) landform representation landform element extraction crater detection aspect granularity aspect-enhanced landform representation America
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An Object-based Approach for Two-level Gully Feature Mapping Using High-resolution DEM and Imagery: A Case Study on Hilly Loess Plateau Region, China 被引量:13
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作者 LIU Kai DING Hu +4 位作者 TANG Guoan ZHU A-Xing YANG Xin JIANG Sheng CAO Jianjun 《Chinese Geographical Science》 SCIE CSCD 2017年第3期415-430,共16页
Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) a... Gully feature mapping is an indispensable prerequisite for the motioning and control of gully erosion which is a widespread natural hazard. The increasing availability of high-resolution Digital Elevation Model(DEM) and remote sensing imagery, combined with developed object-based methods enables automatic gully feature mapping. But still few studies have specifically focused on gully feature mapping on different scales. In this study, an object-based approach to two-level gully feature mapping, including gully-affected areas and bank gullies, was developed and tested on 1-m DEM and Worldview-3 imagery of a catchment in the Chinese Loess Plateau. The methodology includes a sequence of data preparation, image segmentation, metric calculation, and random forest based classification. The results of the two-level mapping were based on a random forest model after investigating the effects of feature selection and class-imbalance problem. Results show that the segmentation strategy adopted in this paper which considers the topographic information and optimal parameter combination can improve the segmentation results. The distribution of the gully-affected area is closely related to topographic information, however, the spectral features are more dominant for bank gully mapping. The highest overall accuracy of the gully-affected area mapping was 93.06% with four topographic features. The highest overall accuracy of bank gully mapping is 78.5% when all features are adopted. The proposed approach is a creditable option for hierarchical mapping of gully feature information, which is suitable for the application in hily Loess Plateau region. 展开更多
关键词 object-based image analysis gully feature hierarchical mapping gully erosion Digital Elevation Model(dem
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HUANNet: A High-Resolution Unified Attention Network for Accurate Counting
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作者 Haixia Wang Huan Zhang +2 位作者 Xiuling Wang Xule Xin Zhiguo Zhang 《Computers, Materials & Continua》 2026年第1期1722-1741,共20页
Accurately counting dense objects in complex and diverse backgrounds is a significant challenge in computer vision,with applications ranging from crowd counting to various other object counting tasks.To address this,w... Accurately counting dense objects in complex and diverse backgrounds is a significant challenge in computer vision,with applications ranging from crowd counting to various other object counting tasks.To address this,we propose HUANNet(High-Resolution Unified Attention Network),a convolutional neural network designed to capture both local features and rich semantic information through a high-resolution representation learning framework,while optimizing computational distribution across parallel branches.HUANNet introduces three core modules:the High-Resolution Attention Module(HRAM),which enhances feature extraction by optimizing multiresolution feature fusion;the Unified Multi-Scale Attention Module(UMAM),which integrates spatial,channel,and convolutional kernel information through an attention mechanism applied across multiple levels of the network;and the Grid-Assisted Point Matching Module(GPMM),which stabilizes and improves point-to-point matching by leveraging grid-based mechanisms.Extensive experiments show that HUANNet achieves competitive results on the ShanghaiTech Part A/B crowd counting datasets and sets new state-of-the-art performance on dense object counting datasets such as CARPK and XRAY-IECCD,demonstrating the effectiveness and versatility of HUANNet. 展开更多
关键词 Accurate counting high-resolution representations point-to-point matching
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Laser additive manufacturing of high-resolution microscale shell lattices by toolpath engineering
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作者 Junhao Ding Shuo Qu +8 位作者 Shengbiao Zhang Zongxin Hu Zhenyong Feng Tianyu Gao Ming Wang Fu Lei Zhang Chinnapat Panwisawas Wen Chen Xu Song 《International Journal of Extreme Manufacturing》 2026年第1期485-500,共16页
Laser additively manufactured microscale metallic lattices show great potential for high-performance applications,yet trade-offs among geometric precision,structural integrity,and computational efficiency still persis... Laser additively manufactured microscale metallic lattices show great potential for high-performance applications,yet trade-offs among geometric precision,structural integrity,and computational efficiency still persist.Here,we introduce a stereolithography file format-free(STL-free)hybrid toolpath generation method for laser-based powder bed fusion(PBF-LB)that synergizes implicit geometric modeling with optimized laser scanning strategy,overcoming these limitations.By circumventing traditional mesh-based workflows,our method directly translates implicit lattice geometries into laser toolpaths while precisely regulating energy deposition trajectories.This mesh-free process enables the fabrication of complex shell lattices with ultra-thin walls and enhanced surface quality.In addition to reducing memory usage and processing time by up to 90%,the method yields a synergistic enhancement in mechanical performance,notably improving both strength and toughness.By bridging computational design and fabrication,this framework enables the scalable production of high-performance microscale lattices and unlocks their potential for industrial applications. 展开更多
关键词 toolpath engineering STL-free hybrid toolpath high-resolution printing laser-based powder bed fusion microscale lattices
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Integrating high-resolution mass spectrometry and transcriptomics to explore the therapeutic mechanism of Sanhuang Oil in diabetic foot
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作者 Ping Sun Yu-Feng Zhang +4 位作者 Shuang Li Wei Zhang Peng-Fei Zhao Chen-Xia Li Chen-Ning Zhang 《Traditional Medicine Research》 2026年第1期19-38,共20页
Background:Diabetic foot,a severe complication of diabetes,is characterized by chronic refractory wounds.Sanhuang Oil,a topical herbal formula,demonstrates significant therapeutic effects including antibacterial,anti-... Background:Diabetic foot,a severe complication of diabetes,is characterized by chronic refractory wounds.Sanhuang Oil,a topical herbal formula,demonstrates significant therapeutic effects including antibacterial,anti-inflammatory,and immunomodulatory activities.However,its active constituents and mechanisms of action against diabetic foot remain to be elucidated.Methods:In this study,the chemical constituents of Sanhuang Oil were identified using UPLC-QE-Orbitrap-MS.Subsequently,the mechanism by which Sanhuang Oil promotes diabetic foot ulcer healing was predicted by integrating network pharmacology and molecular docking.Additionally,diabetic mouse model was established in ICR mice using a combination of a high-fat diet(HFD)and streptozotocin(STZ)chemical induction.A full-thickness skin defect was created on the dorsum of the mice.Wound healing and the healing rate were observed following Sanhuang Oil intervention.The mechanism underlying Sanhuang Oil’s promotion of diabetic ulcer healing was further investigated using transcriptomics and histopathological examination(H&E staining).Results:A total of 97 active ingredients were identified from Sanhuang Oil.Network pharmacology analysis predicted 543 common targets,and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis identified 203 relevant pathways.Molecular docking further confirmed high binding affinity(binding energy≤−5.0 kcal/mol)between specific active components in Sanhuang Oil(e.g.,coptisine,phellodendrine,baicalein)and key targets associated with diabetic foot ulcers(e.g.,EGFR,AKT1,STAT3).In vivo experimental results demonstrated that the wound healing rate was significantly higher in Sanhuang Oil-treated groups compared to the model group(P<0.001).HE staining revealed that the high-dose Sanhuang Oil group exhibited more pronounced epithelial tissue coverage over the wound,reduced inflammatory cell infiltration,and increased collagen deposition and fibroblast proliferation.transcriptomic analysis identified Pdk4,Ttn,Csrp3,Actn2,Myoz2,Tnnc2,Myod1,Myog,Myot,and Myf6 as key regulatory proteins involved in promoting wound healing.Conclusion:Sanhuang Oil promotes wound healing in diabetic ulcer mice,potentially by mitigating inflammation and regulating key targets such as Pdk4 to enhance fibroblast function.These findings provide novel insights into the multi-target,multi-pathway mechanism of Sanhuang Oil for treating diabetic foot ulcers. 展开更多
关键词 Sanhuang Oil diabetic foot high-resolution mass spectrometry molecular network analysis mechanism of action
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Sedimentary Characteristics and Evolution of the High-resolution Sequence Stratigraphic Framework of the Taiyuan Formation in the Hangjinqi Area,Northern Ordos Basin
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作者 ZHAO Mingsheng TIAN Jingchun +1 位作者 SU Bingrui ZHANG Xiang 《Acta Geologica Sinica(English Edition)》 2026年第1期54-68,共15页
The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theor... The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps. 展开更多
关键词 high-resolution sequence framework sedimentary characteristics sedimentary evolution Taiyuan Formation Hangjinqi area northern Ordos Basin
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基于Copernicus DEM 30的大尺度河道数字高程模型重构方法
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作者 李玉建 赵明成 +2 位作者 李琳 戴文鸿 安鹏 《长江科学院院报》 北大核心 2026年第2期201-210,共10页
为解决在大尺度河道数值模拟中河道遥感影像信息不全和实测地形高程资料部分缺失导致河道数字高程模型难以构建的问题,应用塔里木河阿拉尔—新渠满河段2011年相关水文资料与实测地形高程资料,通过ArcGIS软件结合Google Earth历史影像与C... 为解决在大尺度河道数值模拟中河道遥感影像信息不全和实测地形高程资料部分缺失导致河道数字高程模型难以构建的问题,应用塔里木河阿拉尔—新渠满河段2011年相关水文资料与实测地形高程资料,通过ArcGIS软件结合Google Earth历史影像与Copernicus DEM 30数据绘制河道临水线与外缘线,基于二次插值、平均差值法与局部加权回归算法,结合断面高程数据,完善河道地形高程。通过Mesh Generator组件,重构该河段的河道数字高程模型,并检验数据在MIKE 21水动力-泥沙模块数值模拟中的可行性。结果表明:通过模拟得到的流速、流量-水位关系及河道冲淤变化与实测资料对比,各项指标的误差均符合相关技术规程的允许偏差要求;平均差值法可以弥补主槽与河漫滩高程补衔接不自然的问题;局部加权回归算法能有效平滑河道主槽沿程断面高程数据。研究成果旨在丰富河道地形高程数据的重构方法,为解决大尺度河道DEM难以构建问题提供一种新思路。 展开更多
关键词 大尺度河道 数字高程模型(dem) Copernicus dem 30 塔里木河干流
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基于CFD-DEM的微阀射流疏堵模拟研究
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作者 魏列江 张海东 +3 位作者 魏小玲 刘豆豆 陈阳 强彦 《机床与液压》 北大核心 2026年第3期164-170,共7页
针对微阀在长期使用中因微小颗粒物沉积与黏附导致流道堵塞的问题,提出一种通过手指按压储液囊形成射流进行疏通的方法,清除堵塞物的同时避免损伤微阀结构。针对阀芯-阀座间颗粒团聚形成的堵塞,采用CFD-DEM耦合仿真方法,通过改变按压储... 针对微阀在长期使用中因微小颗粒物沉积与黏附导致流道堵塞的问题,提出一种通过手指按压储液囊形成射流进行疏通的方法,清除堵塞物的同时避免损伤微阀结构。针对阀芯-阀座间颗粒团聚形成的堵塞,采用CFD-DEM耦合仿真方法,通过改变按压储液囊时间,研究不同射流条件下颗粒聚集状态。仿真结果表明:当匀速按压时间为1.5 s时,射流速度增长平缓,只有20%的颗粒被冲刷出堵塞位置;按压时间为0.5 s时,射流速度迅速增大,97%的颗粒被冲刷掉,有效改善了微阀堵塞,按压时间显著影响疏堵效率。为进一步验证所提方法的有效性,使用放大样机进行实验验证。结果表明:按压1.5 s后,堵塞的明胶颗粒未能被完全冲刷,大量颗粒仍滞留于阀座区域;而按压时间缩短至0.5 s后,阀芯与阀座之间的明胶颗粒几乎完全被清除,微阀恢复正常工作状态。实验与仿真结果一致,证明基于CFD-DEM耦合仿真模拟按压储液囊射流冲刷堵塞物的方法可行。 展开更多
关键词 微阀 颗粒 堵塞 射流 CFD-dem
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土壤含水率对履带式底盘机动性能影响的DEM-MBD耦合仿真
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作者 王昱 刘佳豪 +4 位作者 曾山 罗毅智 王鹏 姜超 黄梓健 《华南农业大学学报》 北大核心 2026年第2期338-349,共12页
【目的】揭示土壤含水率对农用履带式底盘机动性能的影响机制,明确关键性能指标的突变阈值。【方法】以通用农用履带式底盘为对象,采用离散元(Discrete element method,DEM)与多体动力学(Multi-body dynamics,MBD)耦合仿真方法,构建土壤... 【目的】揭示土壤含水率对农用履带式底盘机动性能的影响机制,明确关键性能指标的突变阈值。【方法】以通用农用履带式底盘为对象,采用离散元(Discrete element method,DEM)与多体动力学(Multi-body dynamics,MBD)耦合仿真方法,构建土壤-履带互作模型。通过堆积角试验标定土壤离散元参数,模拟履带式底盘在土壤含水率(ω)为5%、10%、15%和20%的行驶过程,分析机身速度、沉陷量、轴向偏移量、牵引力、转矩及姿态角(俯仰角、侧倾角)的动态响应。【结果】低含水率(ω≤15%)路面支撑底盘稳定行驶,平均速度0.85~0.88 m/s,变异系数≤1.09%;高含水率(ω=20%)时速度衰减至0.61 m/s,变异系数激增至7.90%,ω=15%为行驶稳定性临界阈值。ω为5%~15%时,稳态沉陷量从70 mm平缓增至150 mm;ω为15%~20%时,稳态沉陷量跃升至370 mm。ω≤10%时,轴向偏移量<200 mm;ω=15%时,偏移量激增;ω=20%时因过度沉陷偏移量回落至118 mm。牵引力随含水率升高线性衰减,驱动转矩非线性增长,高含水率土壤流塑化、打滑加剧需增大转矩克服阻力。俯仰角、侧倾角随含水率呈现“扰动-平衡-再稳定”,ω=15%为姿态突变阈值,ω=20%时姿态波动收窄。【结论】本研究量化分析了土壤含水率临界阈值及底盘性能非线性响应机制,可为履带式底盘适配性设计与田间作业优化提供理论支撑。 展开更多
关键词 履带底盘 土壤含水率 dem-MBD 机动性能 临界阈值
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安徽省典型湖泊DEM模型构建及储水量估算--以平天湖为例
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作者 杨章贤 柯昱琪 朱泽军 《地下水》 2026年第2期228-229,263,共3页
水资源是极其重要的基础性自然资源,是维系经济社会高质量发展和国家生态安全的重要战略资源。本研究以池州市平天湖为例,探索开展湖泊水资源调查,构建水位-面积-储水量关系模型,从而估算不同水文条件下的湖泊储水量。通过该方法可掌握... 水资源是极其重要的基础性自然资源,是维系经济社会高质量发展和国家生态安全的重要战略资源。本研究以池州市平天湖为例,探索开展湖泊水资源调查,构建水位-面积-储水量关系模型,从而估算不同水文条件下的湖泊储水量。通过该方法可掌握全省湖泊水资源禀赋状况,为经济社会高质量发展提供可靠的水资源保障。 展开更多
关键词 湖泊 dem模型 构建 储水量 估算
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半解析CFD-DEM耦合方法研究进展
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作者 许成顺 苏卓林 +1 位作者 徐佳琳 吴昕怡 《土木工程学报》 北大核心 2026年第2期1-19,共19页
流体-颗粒相互作用广泛存在于岩土工程、生物能源与工业过程等领域,CFD-DEM耦合方法因其能同时解析流体连续相与颗粒离散相的动态行为,已成为该类多相系统模拟的主流手段。文章系统综述了CFD-DEM耦合方法,重点聚焦于近年来快速发展的半... 流体-颗粒相互作用广泛存在于岩土工程、生物能源与工业过程等领域,CFD-DEM耦合方法因其能同时解析流体连续相与颗粒离散相的动态行为,已成为该类多相系统模拟的主流手段。文章系统综述了CFD-DEM耦合方法,重点聚焦于近年来快速发展的半解析策略。首先梳理了离散单元法在接触模型与非球形颗粒建模方面的进展;其次对比了全解析、非解析与半解析三类耦合方法的适用条件与技术特点;进而详细评述了基于统计核函数、扩散平滑、双网格及粒子点云等主流半解析算法的原理、优势与局限。最后,针对复杂颗粒形态处理、致密饱和体系模拟、多物理场耦合及机器学习融合等方面的挑战,提出未来研究方向。该文旨在为相关领域研究者提供方法选择与模型开发的参考依据,促进半解析CFD-DEM方法在岩土工程及相关领域的深入应用与发展。 展开更多
关键词 CFD-dem耦合 半解析方法 流体颗粒相互作用 孔隙场重构
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基于DEM-MFBD的煤矿机械疲劳失效机理与寿命优化研究
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作者 宋晓燕 李思齐 《机械管理开发》 2026年第2期159-160,163,共3页
针对煤矿机械长期运行于高负载、强冲击、潮湿高温等极端工况下易发生疲劳损伤的问题,评估煤矿机械在复杂工况下的疲劳寿命并提升其使用寿命。基于DEM-MFBD双向耦合方法,构建煤矿机械与散体物料仿真模型,模拟高负载、强冲击、湿热等极... 针对煤矿机械长期运行于高负载、强冲击、潮湿高温等极端工况下易发生疲劳损伤的问题,评估煤矿机械在复杂工况下的疲劳寿命并提升其使用寿命。基于DEM-MFBD双向耦合方法,构建煤矿机械与散体物料仿真模型,模拟高负载、强冲击、湿热等极端环境下的结构响应与动态应力演化,为煤矿机械疲劳寿命评估提供了思路,并为极端工况下关键部件的可靠性提升提供了可推广的路径。 展开更多
关键词 煤矿机械 疲劳评估 dem-MFBD耦合 疲劳失效机理
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陆探一号SAR数据在矿区形变监测与DEM反演中的应用
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作者 张闯 房平 +6 位作者 姚新宇 董汝旭 卜文超 李浩东 王智雄 刘英 岳辉 《测绘通报》 北大核心 2026年第3期100-105,123,共7页
矿区地表形变的高效监测对灾害防控和生态保护至关重要。本文以东胜煤田露天矿与井工矿为研究对象,基于陆探一号(LT-1)L波段SAR卫星数据,结合D-InSAR和InSAR技术,实现了矿区地表沉降监测与数字高程模型(DEM)反演,并通过实测高程与无人... 矿区地表形变的高效监测对灾害防控和生态保护至关重要。本文以东胜煤田露天矿与井工矿为研究对象,基于陆探一号(LT-1)L波段SAR卫星数据,结合D-InSAR和InSAR技术,实现了矿区地表沉降监测与数字高程模型(DEM)反演,并通过实测高程与无人机数据验证其精度。结果表明:①LT-1数据可有效捕捉大梯度形变(>1 m),露天矿沉降范围广(最大39 cm),井工矿沉降深度大(最大135 cm),且形变点随采掘方向动态迁移;②无控点条件下,LT-1 DEM与无人机DEM的高程差异93%集中在5 m内,满足1∶50000制图标准;③双星编队模式显著提升了监测效率,4 d重访周期可支持矿区形变动态追踪。LT-1数据在复杂矿区形变监测与高精度地形重建中具有优势,为矿山安全与生态修复提供了可靠的技术手段。 展开更多
关键词 LT-1 dem 井工矿 露天矿 沉降监测
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High-resolution Standardized Precipitation Evapotranspiration Index(SPEI)reveals trends in drought and vegetation water availability in China 被引量:1
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作者 Qian He Ming Wang +1 位作者 Kai Liu Bowen Wang 《Geography and Sustainability》 2025年第2期117-130,共14页
Understanding vegetation water availability can be important for managing vegetation and combating climate change.Changes in vegetation water availability throughout China remains poorly understood,especially at a hig... Understanding vegetation water availability can be important for managing vegetation and combating climate change.Changes in vegetation water availability throughout China remains poorly understood,especially at a high spatial resolution.Standardized Precipitation Evapotranspiration Index(SPEI)is an ideal water availability index for assessing the spatiotemporal characteristics of drought and investigating the vegetation-water availability relationship.However,no high-resolution and long-term SPEI datasets over China are available.To fill this gap,we developed a new model based on machine learning to obtain high-resolution(1 km)SPEI data by combining climate variables with topographical and geographical features.Here,we analyzed the long-term drought over the past century(1901–2020)and vegetation-water availability relationship in the past two decades(2000–2020).The century-long drought trend analyses indicated an overall drying trend across China with increasing drought frequency,duration,and severity during the past century.We found that drought events in 1901–1961 showed a larger increase than that in 1961–2020,with the Qinghai-Xizang Plateau showing a significant drying trend during 1901–1960 but a wetting trend during 1961–2020.There were 13.90%and 28.21%of vegetation in China showing water deficit and water surplus respectively during 2000–2020.The water deficit area significantly shrank from 2000 to 2020 across China,which is dominated by the significant decrease in water deficit areas in South China.Among temperature,precipitation,and vegetation abundance,temperature is the most important factor for the vegetation-water availability dynamics in China over the past two decades,with high temperature contributing to water deficit.Our findings are important for water and vegetation management under a warming climate. 展开更多
关键词 Standardized Precipitation Evapotranspiration Index(SPEI) Long-term drought Vegetation-water relationship high-resolution dataset
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Combining machine learning algorithms with traditional methods for resolving the atomic-scale dynamic structure of monolayer MoS_(2) in high-resolution transmission electron microscopy 被引量:1
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作者 Yu Meng Shuya Wang +5 位作者 Xibiao Ren Han Xue Xuejun Yue Chuanhong Jin Shanggang Lin Fang Lin 《Chinese Physics B》 2025年第1期162-170,共9页
High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-co... High-resolution transmission electron microscopy(HRTEM)promises rapid atomic-scale dynamic structure imaging.Yet,the precision limitations of aberration parameters and the challenge of eliminating aberrations in Cs-corrected transmission electron microscopy constrain resolution.A machine learning algorithm is developed to determine the aberration parameters with higher precision from small,lattice-periodic crystal images.The proposed algorithm is then validated with simulated HRTEM images of graphene and applied to the experimental images of a molybdenum disulfide(MoS_(2))monolayer with 25 variables(14 aberrations)resolved in wide ranges.Using these measured parameters,the phases of the exit-wave functions are reconstructed for each image in a focal series of MoS_(2)monolayers.The images were acquired due to the unexpected movement of the specimen holder.Four-dimensional data extraction reveals time-varying atomic structures and ripple.In particular,the atomic evolution of the sulfur-vacancy point and line defects,as well as the edge structure near the amorphous,is visualized as the resolution has been improved from about 1.75?to 0.9 A.This method can help salvage important transmission electron microscope images and is beneficial for the images obtained from electron microscopes with average stability. 展开更多
关键词 aberration measurement high-resolution transmission electron microscopy feature-extraction networks exit-wave reconstruction monolayer MoS_(2)
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直接求解热厚颗粒内传递和反应的生物质快速热解高精度CFD-DEM模拟
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作者 王櫆 任冠龙 +2 位作者 徐骥 葛蔚 熊勤钢 《工程热物理学报》 北大核心 2026年第2期512-520,共9页
热厚颗粒内传递和反应过程的精确建模是生物质快速热解计算流体力学(computational fluid dynamics,CFD)模拟的热点与难点。针对该问题,本工作构建了一种在球形颗粒内引入多壳层直接求解的传递和反应模型,耦合离散单元法(discrete eleme... 热厚颗粒内传递和反应过程的精确建模是生物质快速热解计算流体力学(computational fluid dynamics,CFD)模拟的热点与难点。针对该问题,本工作构建了一种在球形颗粒内引入多壳层直接求解的传递和反应模型,耦合离散单元法(discrete element method,DEM)实现了鼓泡流化床中生物质快速热解过程的高精度模拟。通过单个热厚生物质颗粒热解和实验室尺寸鼓泡床生物质快速热解实验数据验证了直接求解热厚颗粒内传递和反应模型的准确性,并探索了实验室尺度鼓泡床生物质快速热解的特性及操作条件的影响。结果表明,由于能够描述热厚颗粒内显著温度梯度导致的颗粒内径向热解程度的显著差异,本工作所提出的直接求解热厚颗粒内传递和反应模型能够显著提高生物质快速热解CFD-DEM模拟的精度。在操作条件对鼓泡床生物质快速热解的影响研究中发现,生物质颗粒热解的焦油产率随着温度升高先升后降,最佳热解温度在773 K;不同种类的生物质快速热解模拟结果表明焦油产率随纤维素成分的增加而略有增加,其中纯纤维素热解的焦油产率最高。 展开更多
关键词 生物质 快速热解 CFD-dem 热厚颗粒 流化床
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基于CFD-DEM耦合仿真的气吸式核桃定向摆放装置的设计与试验
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作者 刘梦迪 王应彪 +2 位作者 王周梅 张超宇 李九峰 《中国油脂》 北大核心 2026年第1期122-128,共7页
为确保核桃在吸附摆放过程中的姿态固定,设计一种气吸式核桃定向摆放装置。利用CFD-DEM气固两相耦合仿真方法对核桃定向摆放的工作过程进行分析,以核桃与吸口的距离、气流速度、负压强度为考察因素,定向合格指数为评价指标,采用单因素... 为确保核桃在吸附摆放过程中的姿态固定,设计一种气吸式核桃定向摆放装置。利用CFD-DEM气固两相耦合仿真方法对核桃定向摆放的工作过程进行分析,以核桃与吸口的距离、气流速度、负压强度为考察因素,定向合格指数为评价指标,采用单因素试验和响应面试验对核桃定向摆放装置的工作参数进行仿真优化,并结合实际试验验证定向吸附核桃的可行性。结果表明:核桃能被吸起的最低气流速度为25.5 m/s,最小负压强度为-93.6 kPa;影响定向合格指数的因素依次为气流速度、核桃与吸口的距离、负压强度;通过仿真优化和实际试验验证得到气吸式核桃定向摆放装置的最优工作参数为核桃与吸口的距离4 mm、气流速度27 m/s、负压强度-98 kPa,此时平均定向吸附成功率为95%。综上,气吸式核桃定向摆放装置满足核桃定向吸附摆放生产要求。 展开更多
关键词 核桃 气吸式 定向摆放 CFD-dem
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HRAM-VITON: High-Resolution Virtual Try-On with Attention Mechanism
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作者 Yue Chen Xiaoman Liang +2 位作者 Mugang Lin Fachao Zhang Huihuang Zhao 《Computers, Materials & Continua》 2025年第2期2753-2768,共16页
The objective of image-based virtual try-on is to seamlessly integrate clothing onto a target image, generating a realistic representation of the character in the specified attire. However, existing virtual try-on met... The objective of image-based virtual try-on is to seamlessly integrate clothing onto a target image, generating a realistic representation of the character in the specified attire. However, existing virtual try-on methods frequently encounter challenges, including misalignment between the body and clothing, noticeable artifacts, and the loss of intricate garment details. To overcome these challenges, we introduce a two-stage high-resolution virtual try-on framework that integrates an attention mechanism, comprising a garment warping stage and an image generation stage. During the garment warping stage, we incorporate a channel attention mechanism to effectively retain the critical features of the garment, addressing challenges such as the loss of patterns, colors, and other essential details commonly observed in virtual try-on images produced by existing methods. During the image generation stage, with the aim of maximizing the utilization of the information proffered by the input image, the input features undergo double sampling within the normalization procedure, thereby enhancing the detail fidelity and clothing alignment efficacy of the output image. Experimental evaluations conducted on high-resolution datasets validate the effectiveness of the proposed method. Results demonstrate significant improvements in preserving garment details, reducing artifacts, and achieving superior alignment between the clothing and body compared to baseline methods, establishing its advantage in generating realistic and high-quality virtual try-on images. 展开更多
关键词 Virtual try-on attention mechanism high-resolution image generation
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Screening for Illegally Added Drugs in Self-Formulated Feeds Using High-Resolution Mass Spectrometry
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作者 Xing Qianwen Xa Cui +5 位作者 Zhao Fang Cui Shasha Wu Liyong Zhang Liang Li Yandong Han Xue 《Animal Husbandry and Feed Science》 2025年第1期41-48,共8页
[Objective]The paper aimed to effectively reduce the occurrence of bacterial resistance associated with breeding practices and to mitigate food safety risks by controlling the illegal use of veterinary drugs in self-f... [Objective]The paper aimed to effectively reduce the occurrence of bacterial resistance associated with breeding practices and to mitigate food safety risks by controlling the illegal use of veterinary drugs in self-formulated feed at the source.[Method]A screening database comprising 274 illegally added chemical drugs in self-formulated feed was established utilizing ultra-performance liquid chromatography coupled with quadrupole/electrostatic field orbitrap high-resolution mass spectrometry(HPLC-Q-Exactive Focus/MS).Subsequently,253 batches of self-formulated feed samples from various farms in Hebei Province were screened and quantitatively analyzed.[Result]The screening results indicated the presence of 8 pharmaceutical components across 10 batches of self-formulated feed samples,with a detection rate of 3.2%and concentrations ranging from 0.06 to 28851.8μg/g.[Conclusion]The application of high-resolution mass spectrometry is feasible and highly significant for the risk monitoring of illegally added drugs in self-formulated feed. 展开更多
关键词 high-resolution mass spectrometry Self-formulated feed Illegal addition
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Fourier neural operator for high-resolution fluid flow simulation based on low-resolution data:the vorticity equation as an example
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作者 Hongchao Qu Xiongbo Zheng +1 位作者 Lihong Yang Zhenya Song 《Acta Oceanologica Sinica》 2025年第6期165-177,共13页
In oceanic and atmospheric science,finer resolutions have become a prevailing trend in all aspects of development.For high-resolution fluid flow simulations,the computational costs of widely used numerical models incr... In oceanic and atmospheric science,finer resolutions have become a prevailing trend in all aspects of development.For high-resolution fluid flow simulations,the computational costs of widely used numerical models increase significantly with the resolution.Artificial intelligence methods have attracted increasing attention because of their high precision and fast computing speeds compared with traditional numerical model methods.The resolution-independent Fourier neural operator(FNO)presents a promising solution to the still challenging problem of high-resolution fluid flow simulations based on low-resolution data.Accordingly,we assess the potential of FNO for high-resolution fluid flow simulations using the vorticity equation as an example.We assess and compare the performance of FNO in multiple high-resolution tests varying the amounts of data and the evolution durations.When assessed with finer resolution data(even up to number of grid points with 1280×1280),the FNO model,trained at low resolution(number of grid points with 64×64)and with limited data,exhibits a stable overall error and good accuracy.Additionally,our work demonstrates that the FNO model takes less time than the traditional numerical method for high-resolution simulations.This suggests that FNO has the prospect of becoming a cost-effective and highly precise model for high-resolution simulations in the future.Moreover,FNO can make longer high-resolution predictions while training with less data by superimposing vorticity fields from previous time steps as input.A suitable initial learning rate can be set according to the frequency principle,and the time intervals of the dataset need to be adjusted according to the spatial resolution of the input when training the FNO model.Our findings can help optimize FNO for future fluid flow simulations. 展开更多
关键词 Fourier neural operator high-resolution simulation fluid flow vorticity equation
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