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Iterative Subregion Correction Preconditioners with Adaptive Tolerance for Problems with Geometrically Localized Stiffness

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Communications on Applied Mathematics and Computation 2024年第2期6卷 811-836页

作者： Michael Franco per-Olof persson Will Pazner Department of Mathematics University of CaliforniaBerkeleyBerkeleyCA 94720-3840USA Fariborz Maseeh Department of Mathematics and Statistics Portland State UniversityPortlandOR 97201USA

We present a class of preconditioners for the linear systems resulting from a finite element or discontinuous Galerkin discretizations of advection-dominated *** preconditioners are designed to treat the case of geometrically localized stiffness,where the convergence rates of iterative methods are degraded in a localized subregion of the *** convergence may be caused by a number of factors,including the mesh size,anisotropy,highly variable coefficients,and more challenging *** approach taken in this work is to correct well-known preconditioners such as the block jacobi and the block incomplete LU(ILU)with an adaptive inner subregion *** goal of these preconditioners is to reduce the number of costly global iterations by accelerating the convergence in the stiff region by iterating on the less expensive reduced *** tolerance for the inner iteration is adaptively chosen to minimize subregion-local work while guaranteeing global convergence *** present analysis showing that the convergence of these preconditioners,even when combined with an adaptively selected tolerance,is independent of discretization parameters(e.g.,the mesh size and diffusion coefficient)in the *** demonstrate significant performance improvements over black-box preconditioners when applied to several model convection-diffusion ***,we present performance results of several variations of iterative subregion correction preconditioners applied to the Reynolds number 2.25×10^(6)fluid flow over the NACA 0012 airfoil,as well as massively separated flow at 30°angle of attack.

关键词： Subregion correction Nested Krylov Geometrically localized stiffness

Challenging the term symbiosis in plant-microbe associations to create an understanding across sciences

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journal of Integrative Plant Biology 2024年第1期66卷 7-11页

作者： Anna Neubauer Daniela Aros‐Mualin Vicente Mariscal Péter Szövényi Department of Systematic and Evolutionary Botany University of ZurichZurich 8008Switzerland Zurich‐Basel Plant Science Center Zurich 8092Switzerland Instituto de Bioquímica Vegetal y Fotosíntesis CSIC y Universidad de SevillaSevilla 41092Spain

THE IMPORTANCE OF WELL DEFINED TERMINOLOGY,Effective communication across fields and disciplines relies on well defined *** use of accurate definitions has been advocated by scientists across various disciplines(PySek... 详细信息

关键词： terminology definition fields

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新民族学博物馆,布达佩斯,匈牙利

世界建筑 2024年第5期 70-75页

作者：无 Marcel Ferencz Molnár józsef(摄影) 王单单(译) NAPUR建筑设计事务所不详

新民族学博物馆位于布达佩斯市中心的城市公园内,其使命是向匈牙利文化的千年传统致敬,并加强在空间层面上不断发展的民族认同。这种使命具有原创性、不可复制性和不可复原性,通过探索其空间性向来自世界各地的人们传递信息。这座建筑... 详细信息

新民族学博物馆位于布达佩斯市中心的城市公园内,其使命是向匈牙利文化的千年传统致敬,并加强在空间层面上不断发展的民族认同。这种使命具有原创性、不可复制性和不可复原性,通过探索其空间性向来自世界各地的人们传递信息。这座建筑的设计动感而简洁,既与公园的自然环境相协调,又与周围的城市肌理相联系。柔和的曲线使建筑成为连接城市和公园的门户与通道。该建筑有近60%的面积位于地面以下。按照现代博物馆的科学建议,世界级的展览空间不应受自然光照的影响。此外,因景观屋顶和地面部分的透明度,新博物馆在规模上也与周围环境相适应。

关键词：现代博物馆不可复制性周围环境自然光照复原性展览空间城市肌理城市公园

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鸟类形态特征的同质性比较

动物学杂志 2024年第3期59卷 321-336页

作者：郑雪星 per G.P.Ericson 屈延华中国科学技术大学生命科学与医学部合肥230026 中国科学院动物研究所动物进化与系统学院重点实验室北京100010 瑞典自然历史博物馆瑞典斯德哥尔摩50007

鸟类作为脊椎动物中的主要类群之一,其内部演化关系一直是动物学研究的重点。形态特征及分子特征在推断鸟类内部类群间的系统发育关系时被广泛应用,但长久以来受制于同质性的影响,不同形态特征难以得到一致的系统发育关系。随着基因组... 详细信息

鸟类作为脊椎动物中的主要类群之一,其内部演化关系一直是动物学研究的重点。形态特征及分子特征在推断鸟类内部类群间的系统发育关系时被广泛应用,但长久以来受制于同质性的影响,不同形态特征难以得到一致的系统发育关系。随着基因组测序技术及分析方法的快速发展,基于大量DNA序列数据所建的物种树成为领域内普遍认可的鸟类系统发育关系。在此基础之上,重新挖掘形态特征的研究价值成为可能。本研究基于Prum发表于2015年的鸟类科级水平系统发育树,比较了不同形态特征同质性水平的差异,讨论了形态特征对于提高分子特征系统发育信号及分子树支持率的作用。研究发现,不同种类形态特征的同质性水平存在显著的差异,以一致性指数为标准,杂项特征(包括神经、肌腱及肠道的特征)的得分显著高于骨学特征和肌学特征(P<0.01),颅骨特征的得分显著高于非颅骨、躯干及腿部特征的得分(P<0.05);加入形态特征能够显著提高分子特征的系统发育信号(P<0.05),也提高了分子树的支持率。综上所述,不同的形态特征在同质性水平的得分上具有显著差异,在分子特征上加入形态特征既能够提高分子特征的系统发育信号,也能够提高分子树的支持率。

关键词：形态特征同质性水平一致性指数系统发育信号支持率

Storing Freshwater Versus Storing Electricity in Power Systems with High Freshwater Electric Demand

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journal of Modern Power Systems and Clean Energy 2024年第2期12卷 323-333页

作者： Mubarak j.Al-Mubarak Antonio j.Conejo Department of Electrical and Computer Engineering The Ohio State UniversityColumbusOHUSA Department of Electrical Engineering Kuwait UniversityP.O.Box 5969Safat 13060Kuwait Department of Integrated Systems Engineering and the Department of Electrical and Computer Engineering The Ohio State UniversityColumbusOH 43210USA IEEE

We consider a power system whose electric demand pertaining to freshwater production is high(high freshwater electric demand),as in the Middle East,and investigate the tradeoff of storing freshwater in tanks versus storing electricity in batteries at the day-ahead operation *** storing freshwater and storing electricity increase the actual electric demand at valley hours and decrease it at peak hours,which is generally beneficial in term of cost and ***,to what extent?We analyze this question considering three power systems with different generation-mix configurations,i.e.,a thermal-dominated mix,a renewable-dominated one,and a fully renewable *** generation-mix configurations are inspired by how power systems may evolve in different countries in the Middle *** production uncertainty is compactly modeled using chance *** draw conclusions on how both storage facilities(freshwater and electricity)complement each other to render an optimal operation of the power system.

关键词： Power system operation freshwater production and transportation coordination day-ahead scheduling

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湿型砂铸铝:打开新的视角

铸造 2024年第1期73卷 135-138页

作者： per Larsen Tim j.Baron 陈之伟(译) 刘溢(译) DISA Industries A/S 迪砂中国

许多汽车零部件已经用铸铝件替代以前的铸铁件。铸铝件在电动汽车的过渡中至关重要。随着汽车行业的成功转型,大批量的新型电动汽车传动系统铝部件应运而生,如电机壳和机盖。众所周知,湿型砂工艺能高效,可低成本生产出高质量的铸铁件。... 详细信息

许多汽车零部件已经用铸铝件替代以前的铸铁件。铸铝件在电动汽车的过渡中至关重要。随着汽车行业的成功转型,大批量的新型电动汽车传动系统铝部件应运而生,如电机壳和机盖。众所周知,湿型砂工艺能高效,可低成本生产出高质量的铸铁件。随着全球对铸铝件的需求不断上升,降低成本的压力不断加大,越来越多的铸造厂和制造商开始探索湿型砂生产铸铝件的运用。铸铁厂用湿型砂生产的优势成功转移到铸铝件,带来低成本、快速成形和灵活性等优点。

关键词：铸铝件湿型砂铸铁件低成本生产快速成形汽车零部件汽车传动系统电机壳

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Oxidized organic molecules in the tropical free troposphere over Amazonia

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National Science Review 2024年第1期11卷 174-184页

作者： Qiaozhi Zha Diego Aliaga Radovan Krejci Victoria A.Sinclair Cheng Wu Giancarlo Ciarelli Wiebke Scholz Liine Heikkinen Eva Partoll Yvette Gramlich Wei Huang Markus Leiminger joonas Enroth Otso per?kyl? Runlong Cai Xuemeng Chen Alkuin Maximilian Koenig Fernando Velarde Isabel Moreno Tuukka Pet?j? Paulo Artaxo Paolo Laj Armin Hansel Samara Carbone Markku Kulmala Marcos Andrade Douglas Worsnop Claudia Mohr Federico Bianchi Institute for Atmospheric and Earth System Research/Physics University of Helsinki joint International Research Laboratory of Atmospheric and Earth System Sciences Nanjing University Department of Environmental Science & Bolin Centre for Climate Research Stockholm University Department of Chemistry and Molecular Biology University of Gothenburg Institute for Ion and Applied Physics University of Innsbruck Ionicon Analytik GmbH Laboratory for Atmospheric Physics Institute for Physics Research Universidad Mayor de San Andrés Institute of Physics University of Sao Paulo Institute for Geosciences and Environmental Research (IGE) University of Grenoble Alpes Agrarian Sciences Institute Federal University of Uberl?ndia Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Department of Atmospheric and Oceanic Sciences University of Maryland Aerodyne Research Inc. Department of Environmental System Science ETH Zürich Switzerland and Laboratory of Atmospheric Chemistry Paul Scherrer Institute

New particle formation(NPF) in the tropical free troposphere(FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules(OOMs)produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical observations. We performed in situ molecular-level OOMs measurements at the Bolivian station Chacaltaya at 5240 m above sea level, on the western edge of Amazonia. For the first time, we demonstrate the presence of OOMs, mainly with 4–5 carbon atoms, in both gas-phase and particle-phase(in terms of mass contribution) measurements in tropical FT air from Amazonia. These observations, combined with air mass history analyses, indicate that the observed OOMs are linked to isoprene emitted from the rainforests hundreds of kilometers away. Based on particle-phase measurements, we find that these compounds can contribute to NPF, at least the growth of newly formed nanoparticles, in the tropical FT on a continental scale. Thus, our study is a fundamental and significant step in understanding the aerosol formation process in the tropical FT.

关键词： oxidized organic molecules tropical aerosol formation Amazon free troposphere

Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： David j.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Global weirding at mass extinction horizons

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National Science Review 2024年第1期11卷 10-12页

作者： Gregory j.Retallack Department of Earth Sciences University of Oregon

A strong motivation for studying mass extinctions is understanding how current climatic and biodiversity crises will affect creatures living on land such as ourselves. perhaps the question is: how bad can it get? In that case, terrestrial permian-Triassic mass extinctions are an irresistible worst-case scenario [1].

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