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硬化水泥浆体弹性模量细观力学模型

复合材料学报 2007年第2期24卷 184-189页

作者：林枫 meyer Christian 美国哥伦比亚大学土木工程与工程力学系

应用复合材料力学理论和有孔介质力学(Poromechanics)理论建立了一个描述硬化硅酸盐水泥浆体弹性模量的细观力学模型,将硬化水泥浆体从不同尺度上划分为4个层次,即C-S-H凝胶、水泥水化产物、水泥浆体骨架和水泥浆体,分别应用不同的细观... 详细信息

应用复合材料力学理论和有孔介质力学(Poromechanics)理论建立了一个描述硬化硅酸盐水泥浆体弹性模量的细观力学模型,将硬化水泥浆体从不同尺度上划分为4个层次,即C-S-H凝胶、水泥水化产物、水泥浆体骨架和水泥浆体,分别应用不同的细观力学模型予以描述:将C-S-H视为饱和的有孔介质;应用Mori-Tanaka模型描述水泥水化产物的弹性性质;应用三相模型(Three-phase model)模拟水泥浆体骨架的有效弹性模量;最后,再次应用Mori-Tanaka模型和有孔介质理论,计算水泥浆体的排水和不排水弹性模量(Drained and undrainedelastic moduli)。该模型所需要的参数为水泥浆体各个组成部分的自身弹性性质,使用方便。通过预测文献中的实测结果,证明了该模型的有效性。

关键词：硅酸盐水泥浆体有效弹性模量复合材料力学有孔介质力学细观力学模型

Simulation of Random Crack Generation in Concrete Members with Uniform Stress Fields

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Journal of China University of Mining and Technology 2006年第4期16卷 518-522页

作者： LIU Xing LU Wei DENG Xi CHRISTIAN meyer School of Civil Engineering Wuhan University Wuhan Hubei 430072 China Department of Civil Engineering and Engineering Mechanics Columbia University New York 10027 U.S.A

The randomness of strength and deformation of concrete material is serious and should be considered both in theoretical analyses such as Finite Element Methods and engineering practice, specially for those structural members with a uniform stress field, where stresses or strains are approximately the same under loading. A mathematical ap- proach of producing a series of random variables of the ultimate tensile strain in concrete is proposed to describe the randomness ofconcrete deformation. With reinforced concrete finite elements a real model calculation method is found for the randomness of initial cracks determined by a minimum tension strain within the uniform stress fields of concrete members. The proposed methods in our paper have as aim to improve the existing method used by FEM and other rela- tive approaches, which normally pay less attention to randomness with consequences that may possibly differ from testing or practice. The method and sample computation as indicated is meaningful and comply with testing and engi- neering practice.

关键词：混凝土有限元分析水利结构结构力学分析

Multi-level governance through adaptive co-management:conflict resolution in a Brazilian state park

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Ecological Processes 2014年第1期3卷 201-213页

作者： Barbara Schroter Karla Sessin-Dilascio Claas meyer Bettina Matzdorf Claudia Sattler Angela meyer Gregor Giersch Camila Jerico-Daminello Lukas Wortmann Leibniz Centre for Agricultural Landscape Research(ZALF) Institute of Socio-EconomicsEberswalder Straβe 8415374 MünchebergGermany Instituto de Eletrotecnica e Energia(IEE)da Universidade de São Paulo(USP) Servico Tecnico AcademicoSecretaria de Pos GraduacaoAvenida Professor Luciano Gualberto1289Cidade Universitaria05508-010 Sao PauloSPBrazil Organisation for International Dialogue and Conflict Management(IDC) Kaiserstrasse 50/6Vienna 1070Austria

Introduction:Communities situated in protected areas generate conflicts among park administrators,residents and *** they stay or should they go?This article presents a positive example of a community existing in a state *** study describes the community’s governance process as well as how the park administration and the community solve the conflicts that arise and achieve a method of co-management in a multi-level governance ***:The analysis is based on the Management and Transition Framework(MTF).We used a case study approach and collected data via document study,participatory observation and qualitative ***:We find that the agreed system of community-based co-management has improved the implementation and enforcement of the state park’s rules through negotiation and communication mechanisms in the park *** relative success is due to the construction of social capital,equality and ***:For state parks in similar situations,the findings suggest that:1)a community should have at least a minimal level of self-organization;2)the empowerment of the community in the decision-making process is useful;3)the park administration should gain the trust of the residents;and 4)the effective management of ecosystem services can create a win-win situation for the community as well as the park.

关键词： Management of ecosystem services Social capital Protected areas Communities Latin America

Sustainable waste management for zero waste cities in China:potential,challenges and opportunities

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Clean Energy 2020年第3期4卷 169-201页

作者： Roh Pin Lee Bernd meyer Qiuliang Huang Raoul Voss Institute for Energy Process Engineering and Chemical Engineering TU Bergakademie FreibergGermany Fraunhofer IMWS Branch Lab‘Circular Carbon Technologies’ FreibergGermany Institute of Coal Chemistry Chinese Academy of SciencesTaiyuanChina

Waste is a valuable secondary carbon *** the linear economy,it is predominantly landfilled or *** disposal routes not only lead to diverse climate,environmental and societal problems;they also represent a loss of carbon *** a circular carbon economy,waste is used as a secondary carbon feedstock to replace fossil resources for *** contributes to environmental protection and resource *** furthermore increases a nation’s independence from imported fossil energy *** is at the start of its transition from a linear to circular carbon *** can thus draw on waste management experiences of other economies and assess the opportunities for transference to support its development of‘zero waste cities’.This paper has three main *** is an assessment of drivers for China’s zero waste cities initiative and the approaches that have been implemented to combat its growing waste *** is a sharing of Germany’s experience-a forerunner in the implementation of the waste hierarchy(reduce-reuse-recycle-recover-landfill)with extensive experience in circular carbon technologies-in sustainable waste *** is an identification of transference opportunities for China’s zero waste *** transference opportunities identified range from measures to promote waste prevention,waste separation and waste reduction,generating additional value via mechanical recycling,implementing chemical recycling as a recycling option before energy recovery to extending energy recovery opportunities.

关键词： circular carbon economy waste-to-energy zero waste cities sustainable waste management recycling

Cortisol levels in skimmed milk during the first 22 weeks of lactation and response to short-term metabolic stress and lameness in dairy cows

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Journal of Animal Science and Biotechnology 2015年第4期6卷 485-491页

作者： Katharina Gellrich Tanja Sigl Heinrich H.D.meyer Steffi Wiedemann Physiology Weihenstephan Technische Universitaet Muenchen Animal Health Institute of Animal Breeding and HusbandryKiel University

Background： Cortisol is secreted into blood in reaction to acute stress, but also in phases of diminished feed intake and changed animal behavior. As cows do not always show clear signs of discomfort, reliable diagnostic markers could be used to provide information regarding individual cows＇ distress. The objective of this study was to establish an ether free immunoassay for the detection of cortisol and to determine values during the first 22 weeks of lactation. Furthermore, the response in milk cortisol levels was assessed during times of metabolic stress and pain associated symptoms of lameness. Methods： Milk yield and composition, blood serum glucose, NEFA and BHBA as well as milk cortisol were determined in 24 multiparous Holstein-Friesian cows over the course of the first 22 weeks of lactation. Animals were further checked for signs of clinical diseases on a daily basis. Two feed restrictions over three days （FR; 70 % of precious ad libitum intake） were performed during the 4th wk and the 21st wk, respectively. An ELISA for cortisol measurement in easily accessible bovine skimmed milk was established and applied. Results： On the last day of FR in early lactation, a reduction in milk yield and changes in serum metabolites compared to respective previous values were detected. The FR in mid-lactation resulted in no changes in milk production and serum metabolites. Milk cortisol was highest during first wk of lactation and remained on comparable levels thereafter. Milk yield and composition were not influenced by FR. Lameness resulted in enhanced milk cortisol levels. Conclusion： Milk cortisol could be used as an indicator of painful symptoms such as lameness. Higher values of milk cortisol levels during first wk of lactation should be taken into account for interpretation.

关键词： Cortisol Dairy cow ELISA Feed restriction Milk

Phytate:impact on environment and human nutrition.A challenge for molecular breeding

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第3期9卷 165-191页

作者： Lisbeth BOHN Anne S. meyer Sren K. RASMUSSEN Department of Agricultural Sciences Faculty of Life Sciences University of Copenhagen Thorvaldsensvej 40 DK-1871 Frederiksberg C Denmark Department of Chemical Engineering Technical University of Denmark DK-2800 Kgs. Lyngby Denmark Department of Agricultural Sciences Faculty of Life Sciences University of Copenhagen Thorvaldsensvej 40 DK-1871 Frederiksberg CDenmark

Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair, signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes of phytases are compared, and the application of phytase in food and feed is discussed.

关键词：人类环境系统分子呼吸系统

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基于优化算法的串联体系可靠度分析(英文)

计算力学学报 2004年第6期21卷 665-670页

作者：李刚 meyer J 大连理工大学工业装备结构分析国家重点实验室辽宁大连116024 科罗拉多州立大学化学工程系

结构体系的失效概率数学上可以表示为结构体系失效域上联合概率密度函数的积分,一般情况下很难直接积分求解。近几十年来,结构体系可靠度分析一直是可靠度领域的一个研究热点,人们提出许多方法,如:Monte-Carlo法、重要性抽样法与界限法... 详细信息

结构体系的失效概率数学上可以表示为结构体系失效域上联合概率密度函数的积分,一般情况下很难直接积分求解。近几十年来,结构体系可靠度分析一直是可靠度领域的一个研究热点,人们提出许多方法,如:Monte-Carlo法、重要性抽样法与界限法和概率网络估算技术等,这些算法在求解精度、计算效率、收敛性和易使用性等方面是不同的。本文采用优化算法(改进的可行方向法、序列线性规划和序列二次规划法)进行串联体系可靠度分析,并且与其他算法(HL-RF法、Monte-Carlo法和重要性抽样法)的结果以及一些精确解进行了比较。结果表明,相对于其他算法,基于优化算法的可靠度分析适用性广,在收敛性和健实性等方面具有明显的优势。

关键词：体系可靠度一次二阶矩法优化算法 Monte—Carlo法重要性抽样法

Observation of a single protein by ultrafast X-ray diffraction

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Light(Science & Applications) 2024年第1期13卷 80-90页

作者： Tomas Ekeberg Dameli Assalauova Johan Bielecki Rebecca Boll Benedikt J.Daurer Lutz A.Eichacker Linda E.Franken Davide E.Galli Luca Gelisio Lars Gumprecht Laura H.Gunn Janos Hajdu Robert Hartmann Dirk Hasse Alexandr Ignatenko Jayanath Koliyadu Olena Kulyk Ruslan Kurta Markus Kuster Wolfgang Lugmayr Jannik Lübke Adrian P.Mancuso Tommaso Mazza Carl Nettelblad Yevheniy Ovcharenko Daniel E.Rivas Max Rose Amit K.Samanta Philipp Schmidt Egor Sobolev Nicusor Timneanu Sergey Usenko Daniel Westphal Tamme Wollweber Lena Worbs Paul Lourdu Xavier Hazem Yousef Kartik Ayyer Henry N.Chapman Jonas A.Sellberg Carolin Seuring Ivan A.Vartanyants Jochen Küpper Michael meyer Filipe R.N.C.Maia Laboratory of Molecular Biophysics Department of Cell and Molecular BiologyUppsala UniversityHusargatan 3(Box 596)SE-75124 UppsalaSweden Deutsches Electronen-Synchrotron DESY Notkestrasse 8522607 HamburgGermany European XFEL Holzkoppel 422869 SchenefeldGermany Diamond Light Source Harwell Science&Innovation CampusDidcot OX110DEUK University of Stavanger Centre Organelle ResearchRichard-Johnsensgate 44021 StavangerNorway Leibniz Institute for Experimental Virology(HPI) Centre for Structural Systems BiologyNotkestraße 8522607 HamburgGermany Dipartimento di Fisica“Aldo Pontremoli” Universitàdegli Studi di Milanovia Celoria 1620133 MilanoItaly Center for Free-Electron Laser Science DESY22607 HamburgGermany Plant Biology Section School of Integrative Plant ScienceCornell UniversityIthacaNY 14853USA PNSensor GmbH Otto-Hahn-Ring 6D-81739 MünchenGermany Biomedical and X-Ray Physics Department of Applied PhysicsAlbaNova University CenterKTH Royal Institute of TechnologySE-10691 StockholmSweden ELI Beamlines/IoP Institute of Physics AS CR v.v.i.Na Slovance 218221 Prague 8Czech Republic Multi-User CryoEM Facility Centre for Structural Systems BiologyNotkestr.8522607 HamburgGermany University Medical Center Hamburg-Eppendorf(UKE) Martinistrasse 5220246 HamburgGermany The Hamburg Center for Ultrafast Imaging Universität HamburgLuruper Chaussee 14922761 HamburgGermany Department of Physics Universität HamburgLuruper Chaussee 14922761 HamburgGermany Department of Chemistry and Physics La Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneVIC 3086Australia Division of Scientific Computing Science for Life LaboratoryDepartment of Information TechnologyUppsala UniversityBox 337SE-75105 UppsalaSweden European Molecular Biology Laboratory c/o DESYNotkestrasse 8522607 HamburgGermany Department of Physics and Astronomy Uppsala UniversityBox 516SE-75120 UppsalaSweden Max Planck Institute for the Structure and Dynamics of Matter Luruper Chaussee 14922761 HamburgGe

The idea of using ultrashort X-ray pulses to obtain images of single proteins frozen in time has fascinated and inspired *** was one of the arguments for building X-ray free-electron *** to theory,the extremely intense pulses provide sufficient signal to dispense with using crystals as an amplifier,and the ultrashort pulse duration permits capturing the diffraction data before the sample inevitably *** was first demonstrated on biological samples a decade ago on the giant *** then,a large collaboration has been pushing the limit of the smallest sample that can be *** ability to capture snapshots on the timescale of atomic vibrations,while keeping the sample at room temperature,may allow probing the entire conformational phase space of *** we show the first observation of an X-ray diffraction pattern from a single protein,that of Escherichia coli GroEL which at 14 nm in diameter is the smallest biological sample ever imaged by X-rays,and demonstrate that the concept of diffraction before destruction extends to single *** the pattern,it is possible to determine the approximate orientation of the *** experiment demonstrates the feasibility of ultrafast imaging of single proteins,opening the way to single-molecule time-resolved studies on the femtosecond timescale.

关键词： smallest intense ultrafast

Accumulation of Flavonoids in an ntra ntrb Mutant Leads to Tolerance to UV-C

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Molecular Plant 2009年第2期2卷 249-258页

作者： Talaat Bashandy Ludivine Taconnat Jean-Pierre Renou Yves meyer Jean-Philippe Reichheld Laboratoire Genome et Developpement des Plantes Universite de Perpignan UMR CNRS 5096 52 avenue Paul Alduy 66860 Perpignan France Unite de Recherche en Genomique Vegetale 91057 Evry cedex France

NADPH-dependent thioredoxin reductases （NTRs） are key regulatory enzymes determining the redox state of thioredoxins. There are two genes encoding NTRs （NTRA and NTRB） in the Arabidopsis genome, each encoding a cytosolic and a mitochondrial isoform. A double ntra ntrb mutant has recently been characterized and shows slower plant growth, slightly wrinkled seeds and a remarkable hypersensitivity to buthionine sulfoximine （BSO）, a specific inhibitor of gluta- thione biosynthesis. In this paper, we demonstrate that this mutant also accumulates higher level of flavonoids. Analysis of transcriptome data showed that several genes of the flavonoid pathway are overexpressed in the ntra ntrb mutant. Accumulation of flavonoids is generally considered a hallmark of plant stress. Nevertheless, no elevation of the expression of genes encoding ROS-detoxification enzymes was observed, suggesting that the ntra ntrb plants do not suffer from oxidative disease. Another hypothesis suggests that flavonoids are specifically synthesized in the ntra ntrb mutant in order to rescue the inactivation of NTR. To test this, the ntra ntrb mutant was crossed with transparent testa 4 （tt4） plants with a mutation in the gene encoding the first enzyme in flavonoid biosynthesis. As ntra ntrb plants are more resistant to UV-C treatment than wild-type plants, this higher resistance was abolished in the ntra ntrb tt4 mutant, suggesting that accumulation of flavonoids in the ntra ntrb mutant protects plants against UV-light.

关键词： abiotic/environmental stress oxidative and photo-oxidative stress secondary metabolism - phenylpropanoidsand phenolics gene expression Arabidopsis.