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Metal(loid)accumulation and foliar physiological responses in Oryza sativa L.induced by PM1 exposure from various emission sources
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作者 Meixuan Fang Yue Yang +4 位作者 Baofeng Zhang Yingluo Chen Jingdong Mao Liping Lou Qi Lin 《Journal of Environmental Sciences》 2026年第1期585-595,共11页
Foliar uptake of airborne metal(loid)s plays a crucial role in metal(loid)accumulation in plant organs and is influ-enced by the size and emission sources of aerosols.Given the high enrichment of toxic metal(loid)s in... Foliar uptake of airborne metal(loid)s plays a crucial role in metal(loid)accumulation in plant organs and is influ-enced by the size and emission sources of aerosols.Given the high enrichment of toxic metal(loid)s in submicron-scale particulates(PM1),this study established a PM1 exposure system to examine airborne metal(loid)accu-mulation and foliar physiological responses in Oryza sativa L.The results showed that the concentrations of Cu,Zn,As,Pb,and Cd in the leaves and grains were influenced not only by the airborne metal(loid)levels but also by the specific nature of the PM1 particles.The quantitative model for PM1-associated Pb entry into leaf tissue indicated that foliar Pb accumulation was primarily driven by particle adhesion,followed by hydrophilic pene-tration and trans-stomatal liquid film migration,accounting for 87%–89%of the total accumulation.The strong hygroscopicity and high Pb activity of PM1 emitted from waste incineration(WI)increased the Pb absorption coefficient via the hydrophilic and liquid film migration pathway.In contrast,the high hydrophobicity of PM1 from coal burning(CB)led to greater retention of Pb on leaf surfaces.Both foliar reactive oxygen metabolism and photosynthesis indices were sensitive to air pollution.Foliar metal(loid)accumulation and airborne PM1 concentration accounted for the variance in physiological responses in rice leaves.Our results also indicated that Pb was the key element in PM1 emissions from both coal burning(CB)and waste incineration(WI)responsible for significant physiological changes in rice leaves. 展开更多
关键词 Metal(loid) PM1 exposure Coal burning Waste incineration Physiological response Particle nature
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基于两级神经网络的轴承滑油多屑末识别方法
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作者 王冠 武宪威 +4 位作者 钱智 刘电子 李鹏 钱征华 李小剑 《航空动力学报》 北大核心 2025年第7期480-489,共10页
提出了基于误差反向传播神经网络的滑油多屑末识别方法,解决了多屑末信号重叠的难题。提出两级模型框架,第一级网络能准确估计重叠信号中微小屑末的数量,第二级网络利用数量信息,精准分析微小屑末的直径,成功克服了信号重叠带来的挑战... 提出了基于误差反向传播神经网络的滑油多屑末识别方法,解决了多屑末信号重叠的难题。提出两级模型框架,第一级网络能准确估计重叠信号中微小屑末的数量,第二级网络利用数量信息,精准分析微小屑末的直径,成功克服了信号重叠带来的挑战。通过充分数据训练和模型结构优化,模型在单屑末、双屑末和三屑末识别上取得了98.10%、91.42%和93.06%准确率。 展开更多
关键词 多屑末分析 滑油屑末监测 电感式传感器 BP神经网络 金属屑末
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Skeletal progenitor LRP1 deficiency causes severe and persistent skeletal defects with Wnt pathway dysregulation 被引量:1
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作者 Mohammad Alhashmi Abdulrahman M.E.Gremida +15 位作者 Santosh K.Maharana Marco Antonaci Amy Kerr Shijian Fu Sharna Lunn David A.Turner Noor A.Al-Maslamani Ke Liu Maria M.Meschis Hazel Sutherland Peter Wilson Peter Clegg Grant N.Wheeler Robert J.van‘t Hof George Bou-Gharios Kazuhiro Yamamoto 《Bone Research》 2025年第2期384-400,共17页
Low-density lipoprotein receptor-related protein 1(LRP1)is a multifunctional endocytic receptor whose dysfunction is linked to developmental dysplasia of the hip,osteoporosis and osteoarthritis.Our work addresses the ... Low-density lipoprotein receptor-related protein 1(LRP1)is a multifunctional endocytic receptor whose dysfunction is linked to developmental dysplasia of the hip,osteoporosis and osteoarthritis.Our work addresses the critical question of how these skeletal pathologies emerge.Here,we show the abundant expression of LRP1 in skeletal progenitor cells at mouse embryonic stage E10.5 and onwards,especially in the perichondrium,the stem cell layer surrounding developing limbs essential for bone formation.Lrp1 deficiency in these stem cells causes joint fusion,malformation of cartilage/bone template and markedly delayed or lack of primary ossification. 展开更多
关键词 Wnt pathway LRP osteoarthritis stem cell layer multifunctional endocytic receptor developmental dysplasia hip skeletal progenitor cells osteoporosis
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Oral microbiome and inflammatory bowel disease:New understanding and call to action
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作者 Michael Saadeh Sydney Donohue +2 位作者 Shaina Ailawadi Gordon Hong David A Johnson 《World Journal of Gastroenterology》 2025年第38期57-64,共8页
The oral microbiome is the second largest microbial community in the human body after the gut microbiome.It includes an array of fungi,bacteria,amoebae,flagellates,archaea,and viruses,all of which are potential pathog... The oral microbiome is the second largest microbial community in the human body after the gut microbiome.It includes an array of fungi,bacteria,amoebae,flagellates,archaea,and viruses,all of which are potential pathogens.This microbiome can act as a facilitator not only for protection but also for aggravation when dysbiosis occurs.Although conventional thought is this is primarily in terms of oral health issues,such as dental caries and gingival disease.The systemic effects of the oral microbiome however,are relevant to both gastrointestinal(GI)disease and non-GI disease.These systemic risks occur for several reasons,including upregulation of cytokines,adhesion cell-like processes,toll-like receptors,reactive oxidative species or generation of mutation inducing DNA changes.Additionally,there is translocation risk of potential active pathogens or their metabolic byproducts.There is a substantial and growing body of evidence that the oral microbiome influences diseases including Barrett’s esophagus,metabolicassociated steatosis liver disease,and GI cancers.Additionally,there is burgeoning evidence of a causal association with systemic inflammatory diseases,including inflammatory bowel disease.This report discusses the most recent evidence of this association and highlights new approaches to potentially enhance our“best practice”strategies for optimal care of patients with inflammatory bowel disease. 展开更多
关键词 Inflammatory bowel disease Oral microbiome DYSBIOSIS PERIODONTITIS Crohn’s disease Ulcerative colitis Inflammation
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Toward an ecosystem of non‑fungible tokens from mapping public opinions on social media
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作者 Yunfei Xing Justin Z.Zhang +1 位作者 Yuming He Yueqi Li 《Financial Innovation》 2025年第1期111-134,共24页
As blockchain technology advances,non-fungible tokens(NFTs)are emerging as unconventional assets in the commercial market.However,it is necessary to establish a comprehensive NFT ecosystem that addresses the prevailin... As blockchain technology advances,non-fungible tokens(NFTs)are emerging as unconventional assets in the commercial market.However,it is necessary to establish a comprehensive NFT ecosystem that addresses the prevailing public concerns.This study aimed to bridge this gap by analyzing user-generated content on prominent social media platforms such as Twitter,Weibo,and Reddit.Employing text clustering and topic modeling techniques,such as Latent Dirichlet Allocation,we constructed an analytical framework to delve into the intricacies of the NFT ecosystem.Our investigation revealed seven distinct topics from Twitter and Reddit data and eight topics from Weibo data.Weibo users predominantly engaged in reviews and critiques,whereas Twitter and Reddit users emphasized personal experiences and perceptions.The NFT ecosystem encompasses several crucial elements,including transactions,customers,infrastructure,products,environments,and perceptions.By identifying the prevailing trends and common issues,this study offers valuable guidance for the development of NFT ecosystems. 展开更多
关键词 NFTs Public opinion Comparative analysis Text clustering Topic identification TWITTER Weibo Reddit
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A Review of Infrared Thermography Applications for Civil Infrastructure
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作者 Prabal Shrestha Onur Avci +4 位作者 Sahabeddin Rifai Feras Abla Michael Seek Karl Barth Udaya Halabe 《Structural Durability & Health Monitoring》 2025年第2期193-231,共39页
Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operationa... Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operational costs and poses significant risks to public safety.Effective maintenance,repair,and rehabilitation strategies are needed to ensure civil infrastructure’s overall safety and reliability.Non-Destructive Evaluation(NDE)methods are utilized to assess latent damage and provide decision-makers with real-time information for mitigating hazards.Within the last decade,there has been a significant increase in the research and development of innovative NDE techniques to improve data processing and promote efficient and accurate infrastructure assessment.This paper aims to review one of those methods,namely,Infrared Thermography(IRT),and its applications in civil infrastructure.A comprehensive review is presented by investigating numerous journal articles,research papers,and technical reports describing numerous IRT applications for bridges,buildings,and general civil structures made from different materials.The capability of IRT to identify and pinpoint anomalies,typically in the early stages of degradation,has excellent potential to improve the safety and shore up the dependability of civil infrastructures while reducing expenses tied to maintenance and rehabilitation.Furthermore,the non-invasive nature of IRT is beneficial in mitigating disturbances and downtime that may occur during various inspection procedures.It is highlighted that IRT is a highly versatile and effective tool for infrastructure condition assessment.With further advancement and fine-tuning of the available techniques,it is likely that IRT will continue to gain significant popularity in maintaining and monitoring civil infrastructure. 展开更多
关键词 Infrared thermography(IRT) civil infrastructure non-destructive evaluation(NDE)
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Provenance evolution from subduction to arc-continent collision:An example from Zagros–Makran Transition Zone
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作者 Parisa GholamiZadeh Bo Wan +2 位作者 Guido Meinhold Rasoul Esmaeili Mohammad Ebrahimi 《Geoscience Frontiers》 2025年第4期273-289,共17页
Arc-continent collision zones are critical areas where uplift,accretion,and erosion processes significantly influence the growth,elimination,or recycling of the continental crust.The Zagros–Makran Transition Zone,loc... Arc-continent collision zones are critical areas where uplift,accretion,and erosion processes significantly influence the growth,elimination,or recycling of the continental crust.The Zagros–Makran Transition Zone,located along the Minab-Zendan Fault,represents a convergence boundary between the Zagros continental domain and the Makran accretionary prism in southern Iran from the Cretaceous onwards.Several tectonic slices,including Neotethys ophiolitic remnants and the Ganj and Bajgan-Durkan complexes,have accreted along the southern margin of the Eurasian Plate during subduction in the western Makran wedge.To clarify the growth steps of the Makran Prism and the internal deformation associated with arc-continent collision,we used a provenance study of sandstones from the western Makran accretionary prism involving petrography of the main detrital components and U–Pb dating,Hf isotopic values,and trace elements of detrital zircon grains.Our findings reveal a progressive scenario in which oceanic arc-related rocks of the∼99 Ma Ganj Complex with Hf values ranging from+10 to+16 were uplifted during the Early to Late Eocene.The Eocene fore-arc sediments were sourced from the∼49–47 Ma Urumieh-Dokhtar Magmatic Arc with Hf values between−5 and+12,as well as from the Ganj Complex.The Jurassic–Cretaceous Bajgan-Durkan Complex was uplifted due to the Late Eocene to Oligocene collision of various terranes along the southern margin of the Eurasian Plate.This led to a major sediment influx into the Makran trench with a detrital signal in the range∼175–160 Ma with Hf isotopic values from−3 to+4 and alongside the Urumieh-Dokhtar Magmatic Arc with detrital ages ranging∼46–37 Ma and ca.80 Ma.Notably,metamorphic lithic grains began to appear in the sediments in the Late Eocene.The initial arrival of sediments from the Arabian margin to the arc-continent suture zone along the Minab-Zendan Fault indicates the onset of initial collision.During the Late Oligocene–Early Miocene,detrital zircon ages in the range of∼610–520 Ma,sourced from the Arabian basement,were deposited in the trench basin together with components from the Eocene Urumieh-Dokhtar Magmatic Arc and Cretaceous ophiolitic clasts of∼93 Ma with Hf isotopic values of+12 to+16.Following the development and uplift of the orogen from the Middle Miocene onward,detrital zircon grains from the Cretaceous–Miocene Urumieh-Dokhtar Magmatic Arc,Jurassic–Cretaceous Bajgan-Durkan Complex,and Cretaceous ophiolites are present in both the Makran and Zagros sedimentary domains. 展开更多
关键词 Makran prism Arc-continent collision PROVENANCE Detrital zircon U-Pb dating Minab-Zendan Fault
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A Method for Ultrasound Servo Tracking of Puncture Needle
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作者 Shitong Ye Bo Yang +3 位作者 Hao Quan Shan Liu Minyi Tang Jiawei Tian 《Computer Modeling in Engineering & Sciences》 2025年第8期2287-2306,共20页
Computer-aided surgical navigation technology helps and guides doctors to complete the operation smoothly,which simulates the whole surgical environment with computer technology,and then visualizes the whole operation... Computer-aided surgical navigation technology helps and guides doctors to complete the operation smoothly,which simulates the whole surgical environment with computer technology,and then visualizes the whole operation link in three dimensions.At present,common image-guided surgical techniques such as computed tomography(CT)and X-ray imaging(X-ray)will cause radiation damage to the human body during the imaging process.To address this,we propose a novel Extended Kalman filter-based model that tracks the puncture needle-point using an ultrasound probe.To address the limitations of Kalman filteringmethods based on position and velocity,our method of Kalman filtering uses the position and relative velocity of the puncture needle-point instead,and the ultrasonic probe is controlled by a Proportional Integral(PI)controller in X-axis direction and Proportional Derivative(PD)controller in the Y-axis direction.The motion of the ultrasonic probe can be servo-controlled by whether the image information of the puncture needle-point can be detected by the ultrasonic image so that the ultrasonic probe can track the puncture needle-point in real time.The experiment results show that this method has better tracking performance. 展开更多
关键词 Surgical navigation system ultrasonic image servo control position and relative velocity extended Kalman filtering
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Adaptive Fusion Neural Networks for Sparse-Angle X-Ray 3D Reconstruction
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作者 Shaoyong Hong Bo Yang +4 位作者 Yan Chen Hao Quan Shan Liu Minyi Tang Jiawei Tian 《Computer Modeling in Engineering & Sciences》 2025年第7期1091-1112,共22页
3D medical image reconstruction has significantly enhanced diagnostic accuracy,yet the reliance on densely sampled projection data remains a major limitation in clinical practice.Sparse-angle X-ray imaging,though safe... 3D medical image reconstruction has significantly enhanced diagnostic accuracy,yet the reliance on densely sampled projection data remains a major limitation in clinical practice.Sparse-angle X-ray imaging,though safer and faster,poses challenges for accurate volumetric reconstruction due to limited spatial information.This study proposes a 3D reconstruction neural network based on adaptive weight fusion(AdapFusionNet)to achieve high-quality 3D medical image reconstruction from sparse-angle X-ray images.To address the issue of spatial inconsistency in multi-angle image reconstruction,an innovative adaptive fusion module was designed to score initial reconstruction results during the inference stage and perform weighted fusion,thereby improving the final reconstruction quality.The reconstruction network is built on an autoencoder(AE)framework and uses orthogonal-angle X-ray images(frontal and lateral projections)as inputs.The encoder extracts 2D features,which the decoder maps into 3D space.This study utilizes a lung CT dataset to obtain complete three-dimensional volumetric data,from which digitally reconstructed radiographs(DRR)are generated at various angles to simulate X-ray images.Since real-world clinical X-ray images rarely come with perfectly corresponding 3D“ground truth,”using CT scans as the three-dimensional reference effectively supports the training and evaluation of deep networks for sparse-angle X-ray 3D reconstruction.Experiments conducted on the LIDC-IDRI dataset with simulated X-ray images(DRR images)as training data demonstrate the superior performance of AdapFusionNet compared to other fusion methods.Quantitative results show that AdapFusionNet achieves SSIM,PSNR,and MAE values of 0.332,13.404,and 0.163,respectively,outperforming other methods(SingleViewNet:0.289,12.363,0.182;AvgFusionNet:0.306,13.384,0.159).Qualitative analysis further confirms that AdapFusionNet significantly enhances the reconstruction of lung and chest contours while effectively reducing noise during the reconstruction process.The findings demonstrate that AdapFusionNet offers significant advantages in 3D reconstruction of sparse-angle X-ray images. 展开更多
关键词 3D reconstruction adaptive fusion X-ray imaging medical imaging deep learning neural networks sparse angles autoencoder
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Cardiomyopathies of endocrine origin: A state-of-the-art review
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作者 Jenyfer M Fuentes-Mendoza Marcio J Concepción-Zavaleta +7 位作者 Juan C Morón-Siguas Juan M Muñoz-Moreno Aranza I Pérez-Reyes Rodrigo Martinez-Galaviz Raúl D Aguilar-Castañeda Oziel González-Godoy Luis A Concepción-Urteaga José Paz-Ibarra 《World Journal of Cardiology》 2025年第10期20-41,共22页
Endocrine disorders are increasingly recognized as potentially reversible causes of secondary cardiomyopathies,yet they often remain underdiagnosed in clinical practice.These conditions-including thyroid dysfunction,a... Endocrine disorders are increasingly recognized as potentially reversible causes of secondary cardiomyopathies,yet they often remain underdiagnosed in clinical practice.These conditions-including thyroid dysfunction,acromegaly,pheochromocytoma,diabetes mellitus,adrenal disorders,among others-can significantly alter cardiac structure and function through hormonal excess,metabolic remodeling,and neurohumoral activation.Hyperthyroidism may lead to high-output heart failure(HF)and atrial fibrillation,while hypothyroidism is associated with diastolic dysfunction,pericardial effusion,and accelerated atherosclerosis.Acromegaly promotes biventricular hypertrophy and myocardial fibrosis via insulin-like growth factor 1 overproduction.Pheochromocytoma triggers catecholamine-induced cardiomyopathy,resembling Takotsubo syndrome and carrying a high risk of mortality if left untreated.Diabetes induces a distinct phenotype of cardiomyopathy,affecting both systolic and diastolic function through microvascular injury and oxidative stress.Recognizing these endocrine etiologies is crucial,as targeted hormonal therapies-such as antithyroid agents,somatostatin analogs,or adrenalectomy-can reverse or significantly mitigate cardiac dysfunction.Comprehensive endocrine screening in patients with unexplained cardiomyopathy is therefore essential.This review synthesizes current knowledge on the pathophysiological mechanisms,clinical manifestations,and therapeutic strategies for endocrine cardiomyopathies and proposes a diagnostic algorithm for early recognition.Emerging biomarkers,such as galectin-3 in diabetic heart disease,may further enhance diagnostic accuracy and risk stratification.The interplay between endocrine and cardiovascular systems offers a unique opportunity for early intervention,potentially preventing progression to irreversible HF. 展开更多
关键词 Endocrine cardiomyopathy Heart failure Thyroid disease Hormonal screening Cardiac remodeling
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吉兰泰盐湖盆地地下水Cr^(6+)、As、Hg健康风险评价 被引量:24
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作者 高瑞忠 秦子元 +4 位作者 张生 贾德彬 杜丹丹 张阿龙 王喜喜 《中国环境科学》 EI CAS CSSCI CSCD 北大核心 2018年第6期2353-2362,共10页
选取西北干旱区吉兰泰盐湖盆地为研究对象,系统采集71个地下水样品,测定重金属Cr^(6+)、As、Hg,以及主要化学成分的含量,以地质统计学插值绘图揭示盐湖盆地地下水中Cr^(6+)、As、Hg的空间分布特征,以单因子指数法、内梅罗指数法和US EP... 选取西北干旱区吉兰泰盐湖盆地为研究对象,系统采集71个地下水样品,测定重金属Cr^(6+)、As、Hg,以及主要化学成分的含量,以地质统计学插值绘图揭示盐湖盆地地下水中Cr^(6+)、As、Hg的空间分布特征,以单因子指数法、内梅罗指数法和US EPA健康风险评价模型解析地下水中Cr^(6+)、As、Hg的污染及健康风险状况,以统计相关检验进行Cr^(6+)、As和Hg的源分析.结果表明:盐湖盆地地下水中普遍含有Cr^(6+)、As、Hg,Cr^(6+)在盐湖上游及东北部含量较高,As在西南台地含量较高,Hg在西北部巴音乌拉山出现高值区域,其分布与变化受到天然因素和人类活动的双重影响;Cr^(6+)、As出现局部区域超标,超标率分别为8.45%和2.82%;Cr^(6+)主要超标区域在盐湖西南侧呈条块状分布,并在盐湖附近Cr^(6+)含量较高;As以点状超标,分布于西南部和东北部;盐湖盆地地下水87.3%处于安全清洁状态,仅5.6%轻度污染出现在西南部,不存在中度和重度污染;通过饮用水途径的化学致癌物的健康风险值远高于非化学致癌物的健康风险值,西南部图格力高勒沟谷区域化学致癌物Cr^(6+)超过了US EPA最大可接受风险,但整个盐湖盆地Cr^(6+)的平均健康风险值低于US EPA最大可接受风险;As和Hg均低于US EPA最大可接受风险;盐湖盆地总致癌风险特征与Cr^(6+)基本一致,Cr^(6+)平均健康风险占总致癌风险贡献率的89%;Cr^(6+)超标原因包括盐湖盆地高锰酸盐指数偏高,促使Cr3+氧化成为Cr^(6+),As与Cr存在一定的同源关系. 展开更多
关键词 地下水 重金属 空间分布 同源性 健康风险评价 盐湖盆地
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西北内陆盐湖盆地土壤重金属Cr、Hg、As空间分布特征及潜在生态风险评价 被引量:28
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作者 高瑞忠 张阿龙 +4 位作者 张生 贾德彬 杜丹丹 秦子元 王喜喜 《生态学报》 CAS CSCD 北大核心 2019年第7期2532-2544,共13页
选取位于西北内陆的吉兰泰盐湖盆地为研究对象,按照表层(0—10 cm)、50 cm层(50—60 cm)和100 cm层(100—110 cm)分层土壤取样,系统采集了120个样品,测定了重金属Cr、Hg和As,以及主要化学成分的含量,以地统计学插值绘图揭示了吉兰泰盐... 选取位于西北内陆的吉兰泰盐湖盆地为研究对象,按照表层(0—10 cm)、50 cm层(50—60 cm)和100 cm层(100—110 cm)分层土壤取样,系统采集了120个样品,测定了重金属Cr、Hg和As,以及主要化学成分的含量,以地统计学插值绘图揭示了吉兰泰盐湖盆地Cr、Hg和As的空间分布特征,以单因子指数法、内梅罗指数法和潜在生态风险指数法评价解析了盐湖盆地Cr、Hg和As的污染及生态风险状况,以统计相关检验和主成分分析法进行了盐湖盆地Cr、Hg和As的源分析。结果表明:1)盐湖盆地土壤中Cr、Hg、As总体具有相似的空间分布特征,Cr在西北部的巴音乌拉山、乌兰布和沙漠地区和西南台地地区的含量较高,Hg仅在西南低山台地地区、以及东北局部区域的含量较高,As在盐湖附近、东南贺兰山、巴音乌拉山西北部和乌兰布和沙漠地区含量较高;2)基于内蒙古土壤质量背景值,土壤污染分布次序为As>Hg>Cr,其中Hg和As中度污染以上累计比重达到为45%,而Cr仅有7.5%的轻微污染;研究区无清洁土壤,仅有尚清洁土壤占2.5%,开始受到污染和中度污染以上土壤比重为50%和42.5%;土壤潜在风险次序为Hg>As>Cr,Hg整体处于很强生态风险水平;轻微生态风险占到40%,由中度、强度到极强在20%以内,很强生态风险程度略超20%,大部地区处于轻微生态风险状况;3)基于国家土壤环境质量二级标准值,土壤中Cr、Hg、As无论是单因子污染、综合污染,还是潜在生态风险指数均未出现超标区域,不存在Cr、Hg、As污染或潜在生态风险,但相对内蒙古整个地区来说,盐湖盆地Cr、Hg、As含量较高;4)研究区土壤中Cr主要来源于土壤母质形成过程中的自然来源,Hg和As主要来源于工业排放、交通污染源等人类活动,均受到人类活动和自然环境变化的综合影响。 展开更多
关键词 土壤重金属 空间分布 多元统计 潜在生态风险评价 盐湖盆地
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固沙植被黄柳、小叶锦鸡儿蒸腾耗水尺度提升研究 被引量:15
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作者 段利民 童新 +3 位作者 吕扬 闫雪 刘廷玺 Wang Xi-xi 《自然资源学报》 CSSCI CSCD 北大核心 2018年第1期52-62,共11页
论文以科尔沁沙地主要固沙植被黄柳、小叶锦鸡儿为研究对象,基于生长季典型枝条茎流的逐日动态观测数据,以黄柳茎干截面积和小叶锦鸡儿叶面积实测数据为扩展纯量,实现了由枝条茎流向灌丛群落蒸腾耗水的尺度提升。结果表明:生长季黄柳和... 论文以科尔沁沙地主要固沙植被黄柳、小叶锦鸡儿为研究对象,基于生长季典型枝条茎流的逐日动态观测数据,以黄柳茎干截面积和小叶锦鸡儿叶面积实测数据为扩展纯量,实现了由枝条茎流向灌丛群落蒸腾耗水的尺度提升。结果表明:生长季黄柳和小叶锦鸡儿群落的蒸腾耗水量分别为287.26 mm和197.23 mm,黄柳的耐旱性相对较低。采用FAO Penman-Monteith公式计算出同时期两种植被群落的蒸散量分别为328.70 mm和233.15 mm。日蒸腾耗水量与日蒸散量变化趋势基本一致,两种植被的决定系数分别为0.717 3和0.678 7。论文所建立的尺度提升方法在荒漠化灌木植被蒸腾耗水估算方面行之有效,可为科学选育和管理固沙植被、确定合理造林密度等提供参考依据。 展开更多
关键词 荒漠化 茎流 茎干截面积 叶面积 尺度提升
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基于等高线形状分析的LIDAR建筑物提取 被引量:10
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作者 任自珍 岑敏仪 +1 位作者 张同刚 周国清 《西南交通大学学报》 EI CSCD 北大核心 2009年第1期83-88,共6页
基于等高线形状分析,提出了一种新的LIDAR(机载激光雷达)建筑物提取方法.首先利用LIDAR数据生成DSM(数字地面模型)等高线,然后根据等高线形状特征参数,从DSM等高线中提取由建筑物点云形成的等高线(建筑物等高线).最后,根据拓扑关系简化... 基于等高线形状分析,提出了一种新的LIDAR(机载激光雷达)建筑物提取方法.首先利用LIDAR数据生成DSM(数字地面模型)等高线,然后根据等高线形状特征参数,从DSM等高线中提取由建筑物点云形成的等高线(建筑物等高线).最后,根据拓扑关系简化建筑物等高线,再利用建筑物轮廓线相互垂直或平行的特点,对建筑物等高线进行规则化,提取建筑物.实验结果表明,即使在地形起伏的情况下,该方法仍可提取出形状复杂的建筑物,准确率达80%以上. 展开更多
关键词 激光雷达 建筑物提取 等高线 形状分析
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基于等高线的表面估计滤波方法 被引量:6
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作者 任自珍 岑敏仪 +1 位作者 张同刚 周国清 《遥感学报》 EI CSCD 北大核心 2009年第1期91-96,共6页
提出一种基于等高线的滤波方法,它先由LIDAR数据生成数字表面模型,并内插出等高线,再根据DSM等高线的特征,如闭合性、首尾点距离、等高线的长度及等高线间距离等,通过设定阈值自动提取出属于自然地面的等高线线段,以获得初始的自然地面... 提出一种基于等高线的滤波方法,它先由LIDAR数据生成数字表面模型,并内插出等高线,再根据DSM等高线的特征,如闭合性、首尾点距离、等高线的长度及等高线间距离等,通过设定阈值自动提取出属于自然地面的等高线线段,以获得初始的自然地面点,然后内插生成初始数字地面模型,最后使用迭代逼近法生成最终的(精确的)数字地面模型,即比较初始DTM与DSM,差值小于预设阈值的点视为DTM点,而差值大于预设阈值的点则标记为无数据点,最后,这些无数据点由选择的DTM点内插出。通过与现有表面估计的滤波方法的对比实验以及所提取地物轮廓线与航片的叠加对比试验,证明新方法可适用于地表起伏较大的地形,地物提取精度高、计算量小、效率高。 展开更多
关键词 激光雷达 滤波 等高线 数字表面模型 数字地面模型
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科尔沁沙丘草甸相间地区土地利用与覆被识别 被引量:5
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作者 曹文梅 刘廷玺 +3 位作者 王喜喜 王冠丽 李东方 童新 《干旱区研究》 CSCD 北大核心 2021年第2期526-535,共10页
为了实现基于单独光学遥感数据对科尔沁沙丘草甸相间地区土地利用与覆被(LULC)类型的识别,选用2018年64景Sentinel-2影像,结合影像分割技术,利用植被物候信息和生境特征,建立了基于群落水平的LULC决策树识别规则,总体分类精度为0.91,Ka... 为了实现基于单独光学遥感数据对科尔沁沙丘草甸相间地区土地利用与覆被(LULC)类型的识别,选用2018年64景Sentinel-2影像,结合影像分割技术,利用植被物候信息和生境特征,建立了基于群落水平的LULC决策树识别规则,总体分类精度为0.91,Kappa系数为0.89。分类结果显示:研究区旱地分布面积最大,占33.79%,灌木群落次之,占25.03%,高多样性半灌木群落和乔木林相近,分别为14.54%和10%,低多样性半灌木群落、草甸地和流动沙地分别占5%左右,剩余类型的总占比小于5%。该方法不仅可以准确反映研究区覆被类型的空间分布情况,还能给出不同覆被类型的生长发育状况,可为该区域物质循环研究提供基础数据,同时为该区域历史LULC识别提供阈值参考。 展开更多
关键词 遥感 土地利用与覆被 多尺度分割 决策树 分类 哨兵2号卫星 多时相 科尔沁沙地
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基于等高线表面估计法的LIDAR数据DEM提取 被引量:6
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作者 任自珍 岑敏仪 +1 位作者 张同刚 周国清 《测绘科学》 CSCD 北大核心 2008年第6期21-22,38,共3页
本文采用了一种新的利用LIDAR数据提取数字高程模型(DEM)的方法。该方法首先由原始LIDAR数据内插生成数字表面模型(DSM),然后根据DSM等高线闭合及相交情况,将等高线分为非地面等高线和地面等高线,最后内插地面等高线生成当前DEM,并采用... 本文采用了一种新的利用LIDAR数据提取数字高程模型(DEM)的方法。该方法首先由原始LIDAR数据内插生成数字表面模型(DSM),然后根据DSM等高线闭合及相交情况,将等高线分为非地面等高线和地面等高线,最后内插地面等高线生成当前DEM,并采用迭代逼近的方法进行精化,生成最终的DEM。实验证明该方法可以适用于有一定起伏的地形表面,而且该方法原理简单,计算量小,切实可行。 展开更多
关键词 激光雷达 数字表面模型 数字高程模型 等高线
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砂夹层黄土路基水分迁移规律 被引量:7
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作者 晏长根 邹群 +3 位作者 许昱 万琪 石玉玲 马刚峰 《交通运输工程学报》 EI CSCD 北大核心 2016年第6期21-29,共9页
以十天高速公路黄土路基为依托,基于土水势原理提出了在路基土层放置砂夹层来减小黄土层浸水沉陷的发展,采用室内模型试验,在黄土路基中部与底部设置砂夹层,模拟了路基毛细水上升、顶面渗水与边坡渗水的情况,分析了路基含水率变化规律... 以十天高速公路黄土路基为依托,基于土水势原理提出了在路基土层放置砂夹层来减小黄土层浸水沉陷的发展,采用室内模型试验,在黄土路基中部与底部设置砂夹层,模拟了路基毛细水上升、顶面渗水与边坡渗水的情况,分析了路基含水率变化规律及其对路基整体强度和稳定性的影响,并证实了砂夹层的减水阻渗效应。研究结果表明:黄土路基模型初期水分迁移很快,中、后期迁移越来越慢;底部设置砂夹层的路基模块在地下水位上升32d内的体积含水率为24%-27%,纯黄土路基模块的中、下部(路基顶面0.5m以下)的体积含水率约为60%,水分最终的影响深度达到了1.2m;在纯黄土路基模块顶面渗水12d后,体积含水率均超过了60%,而在中部设置了砂夹层的路基模块在夹层下15cm处(路基顶面0.8m以下)的体积含水率小于40%,在25cm处体积含水率小于30%。可见,在压实黄土路基底部与中部设置砂夹层能够阻隔毛细水的上升和减缓水分下渗,减小了路基内部含水率,提高了路基的整体稳定性和强度。 展开更多
关键词 路基工程 黄土路基 含水率 砂夹层 模型试验 水分迁移
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内蒙古高原典型草原内陆河流域径流的时序演变特征 被引量:9
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作者 高瑞忠 白勇 +2 位作者 刘廷玺 王喜喜 王威娜 《南水北调与水利科技》 CSCD 北大核心 2018年第3期10-17,共8页
高原内陆河在我国半干旱地区社会经济发展的区域水资源开发利用过程中起到了重要的支撑作用,认识其演变特征及进行模拟对于流域的可持续发展具有重要的意义。以内蒙古高原典型草原内陆河流域——巴拉格尔河流域为研究对象,基于1959-201... 高原内陆河在我国半干旱地区社会经济发展的区域水资源开发利用过程中起到了重要的支撑作用,认识其演变特征及进行模拟对于流域的可持续发展具有重要的意义。以内蒙古高原典型草原内陆河流域——巴拉格尔河流域为研究对象,基于1959-2015年的水文、气象和社会经济等数据,采用双累积曲线法、累积距平法、改进的M-K趋势检验法和小波变换法对流域径流序列的变化特征进行了解析,并通过细化降水特征因素影响和以社会经济指标量化人类活动影响,运用统计相关检验法筛选径流时序演变模拟的主要输入要素,以改进的BP神经网络实现了水文年、季尺度下径流的时序演变模拟。结果表明:巴拉格尔河流域径流量在年、季尺度下呈现显著减少趋势;径流变化的突变年份为1998年,在这之前受到气候变化为主的影响,而在这之后为加入人类活动的双重影响;年、枯水季径流序列均存在6a和30a周期,而丰水季径流在分析序列内无明显周期变化;降水指标中的降水量、降水天数和降水次数,气候因素中的蒸发和相对湿度,以及人类活动的所有指标是与径流显著相关的影响因素;在无法实现分布式水文模拟时,改进的BP神经网络可以较好地模拟该流域径流的时序演变过程。 展开更多
关键词 时序演变 径流 改进的BP神经网络 小波变换法 高原内陆河
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城市大比例尺真正射影像阴影与遮挡问题的研究 被引量:24
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作者 谢文寒 周国清 《测绘学报》 EI CSCD 北大核心 2010年第1期52-58,共7页
为解决城市大比例尺正射影像生成的问题,从真正射影像的关键技术入手,着重研究其中的阴影与遮挡问题并提出相应解决方法。将这些方法应用在美国丹佛城区的真正射影像生成的项目中,取得了令人满意的效果。
关键词 真正射影像 大比例尺正射影像 城市建筑模型 阴影分析 遮挡检测
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