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塞纳河畔,遇见巴黎

初中生 2024年第15期 4-13页

作者： fe Yun 不详

享有“浪漫之都”美誉的巴黎,城跨塞纳河两岸。河之北为右岸,河之南为左岸。塞纳河畔,古老建筑层出不穷.2024年7月26日到8月11日,第33届夏季奥林匹克运动会将在巴黎举行。这座位于法国北部的繁华之城,将向全世界一展塞纳河畔的无穷魅力。

关键词：浪漫之都塞纳河畔法国北部夏季奥林匹克运动会无穷魅力巴黎

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随机薄片网络的单轴拉伸强度及缺口不敏感性

中国科学：物理学、力学、天文学 2024年第5期54卷 253-268页

作者：张峰潘飞陈玉丽天目山实验室杭州310023 北京航空航天大学航空科学与工程学院北京100191 厦门双瑞风电科技有限公司厦门361000

由高强度高刚度薄片随机组装而成的片状网络材料具有独特的性能和广泛的应用.然而,网络具有显著的随机和离散特征,这些特征对材料的强度和韧性的影响机理还不明确.为此,本文系统研究了随机薄片网络材料在单轴拉伸载荷下的损伤失效演化过... 详细信息

由高强度高刚度薄片随机组装而成的片状网络材料具有独特的性能和广泛的应用.然而,网络具有显著的随机和离散特征,这些特征对材料的强度和韧性的影响机理还不明确.为此,本文系统研究了随机薄片网络材料在单轴拉伸载荷下的损伤失效演化过程,发现了该类材料强度的缺口不敏感性,并揭示了其机理.研究表明,由于网络材料自身的随机和离散特征,层间连接强弱不均且分布随机,因此在单轴拉伸过程中,损伤从弱连接处萌生,并在空间多点离散分布,最终逐渐汇聚成为主裂纹,使得网络呈现韧性断裂特征.正是由于初始损伤为多点分布形式且缺口尖端应力集中有限,导致了随机薄片网络的强度对缺口的不敏感,且与薄片和层间连接的韧性无关.

关键词：随机薄片网络强度韧性缺口敏感性

Assessment of earthquake location uncertainties for the design of local seismic networks

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Earthquake Science 2024年第5期37卷 415-433页

作者： Antonio Fuggi Simone re Giorgio Tango Sergio Del Gaudio Alessandro Brovelli Giorgio Cassiani Isamgeo Italia S.r.l. Gallarate 21013Italy STOGIT S.p.A. UnitàGiacimentiCrema 26013Italy Dipartimento di Geoscienze Universitàdegli Studi di PadovaPadova 35131Italy

The ability to estimate earthquake source locations,along with the appraisal of relevant uncertainties,is paramount in monitoring both natural and human-induced *** this purpose,a monitoring network must be designed to minimize the location errors introduced by geometrically unbalanced *** this study,we first review different sources of errors relevant to the localization of seismic events,how they propagate through localization algorithms,and their impact on *** then propose a quantitative method,based on a Monte Carlo approach,to estimate the uncertainty in earthquake locations that is suited to the design,optimization,and assessment of the performance of a local seismic monitoring *** illustrate the performance of the proposed approach,we analyzed the distribution of the localization uncertainties and their related dispersion for a highly dense grid of theoretical hypocenters in both the horizontal and vertical directions using an actual monitoring network *** results expand,quantitatively,the qualitative indications derived from purely geometrical parameters(azimuthal gap(AG))and classical detectability *** proposed method enables the systematic design,optimization,and evaluation of local seismic monitoring networks,enhancing monitoring accuracy in areas proximal to hydrocarbon production,geothermal fields,underground natural gas storage,and other subsurface *** approach aids in the accurate estimation of earthquake source locations and their associated uncertainties,which are crucial for assessing and mitigating seismic risks,thereby enabling the implementation of proactive measures to minimize potential *** an operational perspective,reliably estimating location accuracy is crucial for evaluating the position of seismogenic sources and assessing possible links between well activities and the onset of seismicity.

关键词： network design earthquake localization detectability localization uncertainties local seismic network

Contribution of SAR Radar Imagery in the Detection of Suspicious Vessels in the Ivorian EEZ

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World Journal of Engineering and Technology 2024年第1期12卷 200-212页

作者： Koffi Cyprien Yoboue Jean-Baptiste Kassi Eric Valère Djagoua Tiemelé Jacque-André Laboratory of remote Sensing and GIS University Center for Research and Application in Remote Sensing (CURAT) Félix Houphouet-Boigny University of Abidjan Cocody Ivory Coast

The present work proposed a method for match SAR and AIS data to detect vessels carrying out suspicious activity in the Ivorian EEZ. Two superposition methods, detected AIS and SAR data, based on point-to-point association on the one hand and point-to-line on the other hand, were used to detect suspicious vessels in Ivorian marine waters. The results showed that most vessels detected in the Ivorian EEZ do not declare their positions to avoid being spotted. These funds are likely to practice illegal, undeclared and unregulated fishing (INN fishing). This clandestine activity is very recurrent in Ivorian waters. This is illustrated by the number of suspicious vessels detected by SAR radar imagery which is greater compared to declared or authorized vessels.

关键词： INN Fishing CFAR Algorithm AIS Sentinel-1A Ivory Coast

喀麦隆西南部Mamelles条带状铁建造元素地球化学特征

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海洋科学 2024年第7期48卷 47-56页

作者： SOH TAMEHE Landry GANNO Sylvestre 陈祖兴 ROSIÈre Carlos Alberto 中国有色桂林矿产地质研究院有限公司广西桂林541004 Department of Earth Sciences University of Yaounde I812 YaoundeCameroon 中国科学院海洋研究所山东青岛266071 Department of Geology Universidade Federal de Minas Gerais31270-901 Belo HorizonteMinas GeraisBrazil

Mamelles铁矿床位于喀麦隆南部刚果克拉通西北缘,距离克里比地区东南方向约20km。该矿床由大规模、高品位磁铁矿矿体组成,赋存于Nyong杂岩体的条带状铁建造(BIF)中。该矿床中的BIF与角闪岩和片麻岩相伴生。在详细的野外调查基础上,我们... 详细信息

Mamelles铁矿床位于喀麦隆南部刚果克拉通西北缘,距离克里比地区东南方向约20km。该矿床由大规模、高品位磁铁矿矿体组成,赋存于Nyong杂岩体的条带状铁建造(BIF)中。该矿床中的BIF与角闪岩和片麻岩相伴生。在详细的野外调查基础上,我们获取了BIF的全岩地球化学数据,并用以约束它们的物质来源和沉积环境。弱正铕(Eu)异常(δEu=2.14~3.55)表明高温热液流体对MamellesBIF的贡献是通过海底火山岩蚀变作用的方式,并有少量碎屑物质输入。正铈(Ce)异常的缺失表明,这些BIF可能沉积在缺氧的深海环境中,如火山弧或弧后盆地深水区。

关键词：刚果克拉通喀麦隆 Mamelles铁矿条带状铁建造地球化学

Effects of Plant residue Decomposition on Soil N Availability,Microbial Biomass and β-Glucosidase Activity During Soil fertility Improvement in Ghana

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Pedosphere 2019年第5期29卷 608-618页

作者： Samuel T. PARTEY Robert B. Z0UGM0re Naresh V. THEVATHASAN Richard F. PreZIOSI CGI AR CCAFS West Africa ProgramInternational Crops Research Institute for the Semi-Arid Tropics (ICRISAT)Bamako B.P. Box 320 (Mali) School of Environmental Sciences University of GuelphGuelph NIG 2W1 (Canada) Faculty of Life Sciences The University of ManchesterManchester M13 9PL (UK)

With limited use of inorganic fertilizers on smallholder farms,plant residues could be viable alternatives for soil fertility *** study was conducted to determine how residue quality and decomposition of nine plant species influence soil N availability,microbial biomass,andβ-glucosidase activity during soil fertility *** differences in N concentration were found among the species,ranging from 12.2 g kg-1 in Zea mays to 39.2 g kg-1 in Baphia *** C/N ratio was the highest in ***(34.4),whereas lignin and polyphenol concentrations were the greatest in Acacia *** highest decomposition rate(0.251%per day)occurred in Tithonia diversifolia,and the lowest in ***,Albizia zygia,***,and ***,with the half-lives of 28-56 *** 80%and 89%of N,P,K,Ca,and Mg were released from *** in 7 d,compared with over 70%retention in ***,***,and *** decomposition and nutrient release half-lives of Gliricidia sepium,Leucaena leucocephala,Azadirachta indica,and Senna spectabilis were less than 14 *** mineral N,microbial biomass,andβ-glucosidase activity increased under all treatments,with *** having the greatest *** N mineralization occurred in all of the species throughout the experiment,an initial N immobilization was recorded in the ***,***,***,and *** treatments for up to 14 *** and nutrient release rates,mineral N,soil microbial biomass,andβ-glucosidase activity were dependent on residue quality,and P and lignin levels,the lignin/N ratio,and the(lignin+polyphenol)/N ratio had the most significant effects(P≤0.05).

关键词： leguminous species litter quality microbial activity N mineralization nutrient release organic matter

Rare etiology of colonic intussusception involving an adult with emphysematous cystic enteropathy:A case report and review of literature

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World Journal of Clinical Cases 2024年第17期12卷 3161-3167页

作者： Eric Bergeron Maude Pichette Geneviève Boisvert Thibaut Manière Étienne Désilets Department of Surgery Charles LeMoyne HospitalGreenfield Park J4V 2H1QuebecCanada Department of Medical Imaging Charles LeMoyne HospitalGreenfield Park J4V 2H1QuebecCanada Department of Gastroenterology Charles LeMoyne HospitalGreenfield Park J4V 2H1QuebecCanada

BACKGROUND Pneumatosis cystoides intestinalis(PCI),characterized by a collection of gas-filled cysts in the intestinal wall,is an uncommon but well-known condition in *** pain is the most frequent symptom associated with *** represents a potential cause of recurrent abdominal pain or emergency ***,the occurrence of colonic intussusception secondary to PCI is very unusual in *** SUMMARY A 52-year-old male,known with idiopathic PCI,presented seventeen months after initial diagnosis with a new right upper quadrant pain.A computed tomographyscan demonstrated a colonic intussusception at the hepatic *** did not progress compared with initial *** patient underwent an emergency right *** resection was recommended in this case because PCI proved to be persisting with no identified curable *** allowed to address the underlying pathology,the potential relapse of intussusception,and the likely cause of recurrent abdominal pain,either invagination or PCI itself.

关键词： Pneumatosis cystoides intestinalis Colonic intussusception Colonic obstruction Colonoscopy Case report

Effect of excitation wavelength(blue vs near UV)and dopant concentrations on afterglow and fast decay of persistent phosphor SrAl_(2)O_(4):Eu^(2+),Dy^(3+)

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Journal of Rare Earths 2022年第7期40卷 1022-1028页

作者： Bernhard Walfort nando Gartmann Jafar Afshani Arnulf Rosspeintner Hans Hagemann LumiNova AG SwitzerlandSpeicherstrasse 60aCH-9053TeufenSwitzerland Dépt.de Chimie Physique Universitéde Genève30Quai E.AnsermetCH 1211Geneva 4Switzerland

The persistent phosphor SrAl_(2)O_(4):Eu^(2+),Dy^(3+)is the subject of numerous *** often neglected aspect is that in this phosphor,as well as in Sr_(4)Al_(14)O_(25):Eu^(2+),Dy^(3+),there are two different Sr^(2)+sites which can be occupied by the dopant Eu^(2+)ions,We first introduce a general scheme of possible energy transfers in these persistent phosphor materials including explicitly both europium ions,This scheme is used as a generic starting point to study experimentally specific *** illustrate this application with the study of the effect of excitation wavelength(444 and 382 nm)on the afterglow of differently doped SrAl_(2)O_(4):Eu^(2+),Dy^(3+)samples,as well as on the emission decay *** the same excitation intensity under 444 nm excitation,the resulting afterglow intensity is stronger than under near UV *** 382 nm,Eu^(2+)ions on both Sr^(2)+s ites in SrAl_(2)O_(4)are excited,but at room temperature the blue emission is quenched,leading to a loss of *** observed effects can further be associated with the ratio of Eu^(2+)ions and trap states which are modulated by the concentrations of Eu^(2+)and Dy^(3+)in SrAl_(2)O_(4),as well as by temperature,Increasing the nominal Dy^(3+)content from 0.1 mol%to 0.5 mol%with respect to Sr results in the doubling of the integrated afterglow intensity and confirms thus that Dy^(3+)ions are indeed involved in the trapping process,The concentration of trap states is much lower than the concentration of Eu^(2+)ions,as even with low excitation densities,a plateau of integrated afterglow intensity(corresponding to the total number of accessible traps)is *** postulate that an important fraction of excited Eu^(2+)ions can potentially transfer their energy to trap *** that all traps are filled or in a dynamical filling-depletion process under illumination(with thermal and/or optical depletion processes),for the remaining Eu^(2+)a"normal"steady-state emission is observed

关键词： Persistent phosphor Strontium aluminate Europium Forster energy transfer Rare earths

云计算环境下基于X-means优化聚类的海量多源异构数据分类

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北部湾大学学报 2024年第2期39卷 40-46页

作者：陶迎松安徽工商职业学院信息化建设与发展处安徽合肥231131

大数据分类算法在处理海量多源异构数据时存在精度差、效率低等问题,为此提出了一种在云计算环境下基于X-means的优化聚类算法。先构建云计算框架体系,包括用户层、应用层、平台层、资源层和后台管理层;基于RF优化算法对多源异构数据集... 详细信息

大数据分类算法在处理海量多源异构数据时存在精度差、效率低等问题,为此提出了一种在云计算环境下基于X-means的优化聚类算法。先构建云计算框架体系,包括用户层、应用层、平台层、资源层和后台管理层;基于RF优化算法对多源异构数据集做融合预处理,降低泛化误差的同时也能实现对数据集的粗分类;基于X-means优化聚类算法计算出数据聚类数量上下限值,不但提升数据训练的效率和降低算法的复杂度,还使距离平均误差值得到较好的控制。在实验室搭建了1个master节点和5个slave节点的云框架,实验结果显示,提出的分类算法在处理海量多源异构数据集时具有更强的分类精度和抗漂移性,同时在分类效率方面也具有一定优势。

关键词：云计算 X-means优化聚类 RF优化算法融合预处理距离平均误差值