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Finite element investigation of steel built-up shear links subjected to inelastic deformations

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Earthquake Engineering and Engineering Vibration 2004年第2期3卷 195-203页

作者： Peter Dusicka Ahmad M.Itani ian G.Buckle Department of Civil and Environmental Engineering Portland State UniversityP O.Box 751PortlandOregon97207USA Assistant Professor Department of Civil Engineering Mail Stop 258University of NevadaRenoNevada89557USA Associate Professor Department of Civil Engineering Mail Stop 258University of NevadaRenoNevada89557USA Professor

Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.

关键词： finite element investigation steel built-up shear link inelastic deformation

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内生型产业遗产及其分类研究

自然与文化遗产研究 2024年第5期9卷 1-10页

作者：王雨晨潜伟王冬冬北京科技大学科技史与文化遗产研究院北京100083

“内生型产业遗产”指工业革命之前中国本土已经存在的、具有自主研发技术的产业相关遗产。内生型产业遗产集中呈现了古代中国特色的技术类型和发展脉络,体现了中国产业遗产的历史性和丰富性,与其他时空框架下的产业遗产存在显著差异。... 详细信息

“内生型产业遗产”指工业革命之前中国本土已经存在的、具有自主研发技术的产业相关遗产。内生型产业遗产集中呈现了古代中国特色的技术类型和发展脉络,体现了中国产业遗产的历史性和丰富性,与其他时空框架下的产业遗产存在显著差异。目前学界鲜见对其内涵、构成和类型的系统性讨论。文章辨析相关概念,提出“内生型产业遗产”概念,并在此基础上,综合考量古代中国产业面貌和现存遗产类型、构成、数量等因素,基于遗产原初的行业类别和生产流程对内生型产业遗产进行分类,助力构建衡量技术价值的横向比较框架,为后续开展相关研究提供新的切入角度,为实际的遗产认定和保护利用工作提供参考。

关键词：产业遗产内生遗产分类技术价值工业遗产

维普期刊数据库博看期刊

Evidence for the ef?cacy and safety of herbal weight loss preparations

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Journal of Integrative Medicine 2019年第2期17卷 87-92页

作者： Rachael Farrington ian F.Musgrave Roger W.Byard Adelaide Medical School The University of Adelaide Forensic Science SA

Rising rates of obesity across the globe have been associated with an increase in the use of herbal preparations for weight control. However, the mechanisms of action for these substances are often not known,as is the potential for interaction with other herbal preparations or prescription pharmaceutical drugs. To investigate the reported efficacy and safety of herbal weight loss preparations, we conducted a review of the literature focusing on herbs that are most commonly used in weight loss preparations, specifically,Garcinia cambogia, Camellia sinensis, Hoodia gordonii, Citrus aurantium and Coleus forskohlii. There was no clear evidence that the above herbal preparations would cause sustained long-term weight loss in humans in the long term. Serious illness and even death have occasionally resulted from the use of herbal weight loss preparations. Few clinical trials have been undertaken to evaluate the efficacy and/or safety of herbal weight loss preparations. In addition, potential issues of herb–herb and herb–drug interactions are often not considered. Regulation of these products is much less rigorous than for prescription medications, despite documented cases of associated hepatotoxicity.

关键词： Weight loss Hepatotoxicity Complementary medicine Traditional Chinese medicine

Seasonal variation of tidal prism and energy in the Changjiang River estuary： a numerical study

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Chinese Journal of Oceanology and Limnology 2016年第1期34卷 219-230页

作者：张敏 ian Howard TOWNEND 蔡华阳周云轩 State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China Ocean and Earth Sciences University of Southampton Southampton SO171B J UK Department of Water Management Faculty of Civil Engineering and Geosciences Delft University of Technology Stevinweg 1 P.O. Box 5048 2600 GA Delft The Netherlands

Tidal rivers are intrinsically complex because tidal propagation is influenced by river discharge. This study aims to examine the seasonal variation of tidal prism and energy variance in the tidal river of the Changjiang(Yangtze) River estuary in China. In order to quantify the behaviour of river and tide,we use numerical modelling that has been validated using measured data. We conduct our analysis by quantifying the discharge and energy variance in separate components for both the river and the tide,during wet and dry seasons. We note various definitions of tidal prism and explore the difference between tidal discharge on the flood and ebb and tidal storage volume. The results show that the river discharge attenuates the tidal motion and reduces the tidal flood discharge but the tidal storage volume is approximately constant with different riverine discharge since part of the fresh water discharge is intercepted and captured in the estuary due to the backwater effect. It appears that the tidal discharge adjusts according to the variation of river discharge to keep a constant tidal storage volume. An analysis of the hydraulics shows that the transition from tidal dominance(at the mouth) to river dominance(upstream) depends on the location of tidal current reversal which varies from wet season to dry season. Duringthe wet season,the Changjiang River estuary is totally dominated by energy from fresh water discharge.

关键词： hydrodynamics estuary convergence tidal prism hydraulics energy tidal river

Quality Model and Metrics of Ontology for Semantic Descriptions of Web Services

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Tsinghua Science and Technology 2017年第3期22卷 254-272页

作者： Hong Zhu Dongmei Liu ian Bayley Arantza Aldea Yunfei Yang Ying Chen Department of Computing and Communication Technologies Oxford Brookes University School of Computer Science and Engineering Nanjing University of Science and Technology

An ontology is a conceptualisation of domain knowledge. It is employed in semantic web services technologies to describe the meanings of services so that they can be dynamically searched for and composed according to their meanings. It is essential for dynamic service discovery, composition, and invocation. Whether an ontology is well constructed has a tremendous impact on the accuracy of the semantic description of a web service, the complexity of the semantic definitions, the efficiency of processing messages passed between services, and the precision and recall rates of service retrieval from service registrations. However, measuring the quality of an ontology remains an open problem. Works on the evaluation of ontologies do exist, but they are not in the context of semantic web services. This paper addresses this problem by proposing a quality model of ontology and defining a set of metrics that enables the quality of an ontology to be measured objectively and quantitatively in the context of semantic descriptions of web services. These metrics cover the contents, presentation, and usage aspects of ontologies. The paper also presents a tool that implements these metrics and reports a case study on five real-life examples of web services.

关键词： semantic web services ontology quality model ontology evaluation ontology metrics

JA but not JA-Ile is the cell-nonautonomous signal activating JA mediated systemic defenses to herbivory in Nicotiana attenuata

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Journal of Integrative Plant Biology 2017年第8期59卷 552-571页

作者： Tobit A. Bozorov Son Truong Dinh ian T. Baldwin Department of Molecular Ecology Max Planck Institute for Chemical EcologyHans-Knoll-Str.8D-07745JenaGermany Institute of Genetics and Plants Experimental Biology Uzbek Academy of SciencesYukori-Yuz111226KibrayTashkent RegionUzbekistan Department of Plant Biotechnology Faculty of Biotechnology-Vietnam National University of AgricultureNgo Xuan Quang Street100000HanoiVietnam

The whole-plant activation of defense responses to wounding and herbivory requires systemic signaling in which jasmonates （JAs） play a pivotal role. To examine the nature of the slower cell-nonautonomous as compared to the rapid cell-autonomous signal in mediating systemic defenses in Nicotiana attenuata, reciprocal stem graftingexperiments were used with plants silenced for the JA biosynthetic gene ALLENE OXIDE CYCLASE （irAOC） or plants transformed to create JA sinks by ectopicalIy expressing Arabidopsis JA-O-methyltransferase （ovJMT）. JA-impaired irAOC plants were defective in the cell-nonautonomous signaling pathway but not in JA transport. Conversely, ovJMT plants abrogated the production of a graft-transmissible JA signal. Both genotypes displayed unaltered cell-autonomous signaling. Defense responses （17-hydroxygeranyllinalool diterpene glycosides, nicotine, and proteinase inhibitors） and metabolite profiles were differently induced in irAOC and ovJMT scions in response to graft-transmissible signals from elicited wild type stocks. The performance of Manduca sexta larvae on the scions of different graft combinations was consistent with the patterns of systemic defense metabolite elicitations. Taken together, we conclude that JA and possibly MeJA, but not JA-lle, either directly functions as a long-distance transmissible signal or indirectly interacts with long distance signal（s） to activate systemic defense responses.

关键词： JASMONIC ACID PLANT-RESPONSES METHYL JASMONATE GENE-EXPRESSION WOUND RESPONSE PROTEINASE-INHIBITORS DITERPENE GLYCOSIDES PROTEASE INHIBITORS INSECT HERBIVORES INDUCED INCREASES

Origin and evolution of the genera Lonsdaleia and Actinocyathus:Insights for the Mississippian palaeogeography from the western Palaeotethys

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Journal of Palaeogeography 2023年第2期12卷 296-310页

作者： Isabel Rodríguez-Castro ian D.Somerville Sergio Rodríguez Departamento de Geodinamica Estratigrafía y PaleontologíaUniversidad Complutense de Madrid28040MadridSpain UCD School of Earth Sciences University College DublinBelfieldDublin 4Ireland Instituto de Geociencias(CSIC UCM)Ciudad Universitaria28040MadridSpain

Representatives of the subfamily Lonsdaleiinae Chapman,1893 are common in the Mississippian of the western Palaeotethys.A general analysis of the origin,distribution and evolution of that subfamily has been *** most probable hypothesis for the origin of the genus Lonsdaleia McCoy,1849 is to acquire colonialism via the genus Axophyllum Milne Edwards and Haime,*** d'Orbigny,1849 would be a descendant of Lonsdaleia by increasing integration in the *** first occurrences of Lonsdaleia have been recorded in the lower Visean from northern Britain and northern Tianshan Mountains of northwestern China,but the diversification and migration to the whole Palaeotethys only happened in the late *** hypotheses are proposed on that *** Serpukhovian was also a period of migrations and diversification for these *** Lonsdaleia and Actinocyathus have been recorded in Bashkirian refuges,the Sverdrup Basin in northern Laurasia and the Tindouf Basin in northern Africa,*** division of the western Palaeotethys into six subprovinces based on the distribution of corals is proposed.

关键词： Carboniferous Palaeotethys Biogeography Evolution Rugosa

NUMERICAL SIMULATION OF THE TROPICAL INTRASEASONAL OSCILLATION AND THE EFFECT OF WARM SST

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Acta meteorologica Sinica 1995年第1期9卷 1-12页

作者：李崇银 ian Smith Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100080 Centre for Drought Research CSIRO Division of AtmOspheric ResearchPBN 1MordiallocVic.3195Australia

An atmospheric general circulation model is used in a series of three experiments to simulate the intraseasonal oscillation in the tropical *** of the model daily data show that various physical variables,from sever- al different regions,exhibit fluctuations with a spectral peak between 30 and 60 *** represents a 30—60 day oscillation in the tropical atmosphere and possesses several features which are consistent with *** in- clude a horizontal structure dominated by zonal wavenumber 1 and a vertical structure which is predominantly baroclinic. The effect of warm SST (sea surface temperature) anomalies on the 30—60 day oscillation in the tropical atmos- phere is also simulated by prescribing global SST as observed in *** has the effect of weakening the oscillation while at the same time the vertical structure becomes less baroclinic. The importance of cumulus convection to the propagational characteristics of this oscillation is demonstrated by a comparison of results based on different parameterizations for *** one case,where the maximum convection over the Pacific is simulated to be too far east,the simulated 30—60 day oscillation shows evidence of westward propa- *** the second case,where the convection maximum is located near the observed position in the western Pacific, there is more clearly evidence of eastward propagation. Both results suggest that the location of maximum convection in the Pacific can have an important influence on the strength,structure and propagation of the 30—60 day oscillation.

关键词： numerical experiment tropical intraseasonal oscillation cumulus convection sea surface temperature anomalies(SSTA)

Litter buffet:On the use of trash bins by birds in six boreal urban settlements

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Avian Research 2023年第2期14卷 182-190页

作者： Michelle García-Arroyo Miguel A.Gomez-Martínez ian MacGregor-Fors Ecosystems and Environment Research Programme Faculty of Biological and Environmental SciencesUniversity of HelsinkiNiemenkatu 73Lahti15140Finland Instituto de Biotecnología y Ecología Aplicada(INBIOTECA) Universidad VeracruzanaXalapa91090Mexico

Unintentional food resources in urban areas(street litter,food leftovers,overflowing trash bins)are dietary components of some urban-exploiter bird *** this study,we report on 13 bird species in six southern Finnish cities using urban trash bins and describe differences in their activity when provided with food resources(i.e.,bait)in different bin *** used generalized linear models(GLM)and classification and regression trees(CART)to test for associations between environmental variables and bird activity at the *** activity at the binscapes significantly differed among all cities and among types of bins and was significantly higher after placing bait in all *** with the largest opening had more activity as opposed to those with smaller openings or *** and gulls had the highest activity,with corvids usually being present before the bait was placed and gulls increasing their activity *** differences show that trash bin foraging is highly malleable and thus susceptible to management preventing its *** waste management measures could aid in reducing the number of species close to bins and their surroundings,benefiting both bird and human health.

关键词： Avian Behavior Binscape Food resources Urban ecology