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Multiscale friction model for hot sheet metal forming

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Friction 2022年第2期10卷 316-334页

作者： Jenny VENEMA Javad HAZRATI Eisso ATZEMA david matthews Ton van den BOOGAARD Tata Steel Research&DevelopmentCA Ijmuiden 1970the Netherlands Nonlinear Solid Mechanics Faculty of Engineering TechnologyUniversity of TwenteEnschede 7522 NBthe Netherlands Laboratory for Surface Technology and Tribology Faculty of Engineering TechnologyUniversity of TwenteEnschede 7522 NBthe Netherlands

The accurate description of friction is critical in the finite element(FE)simulation of the sheet metal forming ***,friction is oversimplified through the use of a constant Coulomb friction *** this study,the application of an existing multiscale friction model is extended to the hot stamping *** model accounts for the effects of tool and sheet metal surface topography as well as the evolution of contact pressure,temperature,and bulk strain during hot *** load flattening and strip drawing experiments are performed to calibrate the *** results show that the model can relatively well predict friction in strip draw experiments when the tool surface evolution due to wear is ***,the application of the formulated multiscale friction model was demonstrated in the FE simulation of a hot-stamped part.

关键词： tribology wear friction hot stamping friction model

Evaluation of Offshore Wastewater Outfall and Diffuser for Onondaga Lake, NY

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Journal of Water Resource and Protection 2013年第9期5卷 1-15页

作者： Emmet M. Owens Steven W. Effler david A. matthews Anthony R. Prestigiacomo Upstate Freshwater Institute Syracuse USA

Outfall alternatives are evaluated for a municipal wastewater treatment facility that discharges effluent at the shoreline of an urban lake. Occurrence of plumes of poorly diluted effluent in adjoining portions of the lake is described. Alternatives considered include outfalls over a range of depth and various diffuser designs. Benefits and impacts on lake stratification and dissolved oxygen are evaluated for an array of design alternatives with a model which links a far field hydrothermal and transport submodel with a near field buoyant plume submodel. Outfall design features are described that: 1) reduce shoreline discharge of bypass flow of partially treated wastewater during major runoff events;2) eliminate plumes of poorly diluted effluent;and 3) reduce loading of the effluent to the upper waters. A deep (10 to 14 m) outfall with a multiport diffuser would reduce the loading of the facility’s effluent to the upper waters by approximately 40%, without noteworthy impact on stratification or dissolved oxygen.

关键词： Mathematical Model Outfall Diffuser Near Field Dilution Eutrophication

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精神健康与垄断资本主义关系论析

国外理论动态 2020年第3期 75-83页

作者：大卫·马修斯王文彬(译) 王满林(译) 威尔士兰德里洛学院辽宁大学公共基础学院北京师范大学哲学学院

保罗·巴兰和保罗·斯威齐的《垄断资本》一书阐述了资本主义的种种矛盾,其中包含了一系列关于资本主义与精神健康之间关系的观点和论断。虽然成书于50多年前,但这些观点和论断如今看来仍然具有重要意义。文章主要基于该书的两位作者的... 详细信息

保罗·巴兰和保罗·斯威齐的《垄断资本》一书阐述了资本主义的种种矛盾,其中包含了一系列关于资本主义与精神健康之间关系的观点和论断。虽然成书于50多年前,但这些观点和论断如今看来仍然具有重要意义。文章主要基于该书的两位作者的相关成果,从心理发展与垄断资本主义、弗洛伊德左派、力比多的压抑、异化与心理发展、垄断资本主义下的异化与理性主义等方面分析了垄断资本主义与精神健康之间的关系。垄断资本主义促使精神健康不良持续蔓延,后者是一种辩证现象,由生产方式与个人内在需求之间的对立关系演化而来。资本主义挑战了人类和人性赖以发展的基础,工人阶级唯有奋起反击,才能扭转一切形式的人性退化。

关键词：精神健康垄断资本主义《垄断资本》力比多异化

Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

One-dimensional monotone nonautonomous dynamical systems

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Science China Mathematics 2024年第2期67卷 281-314页

作者： david Cheban Faculty of Mathematics and Computer Science Laboratory of Fundamental and Applied MathematicsMoldova State UniversityChisinau 2009Moldova

This work is devoted to the study of the dynamics of one-dimensional monotone nonautonomous(cocycle) dynamical systems. A description of the structures of their invariant sets, omega limit sets,Bohr/Levitan almost periodic and almost automorphic motions, global attractors, and pinched and minimalsets is given. An application of our general results is given to scalar differential and difference equations.

关键词： one-dimensional dynamics pinched and minimal sets global attractors monotone nonautonomous cocycle almost periodic solutions scalar differential/difference equations

Kerogen Kinetic Distributions and Simulations Provide Insights into Petroleum Transformation Fraction (TF) Profiles of Organic-Rich Shales

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Journal of Earth Science 2024年第3期35卷 747-757页

作者： david A.Wood DWA Energy Limited Lincoln LN59JPUnited Kingdom

Two hundred and fifty single first-order Arrhenius reactions are simulated to generate S2 pyrograms at three heating rates 25,15,and 5°C·*** activation energy(E)and pre-exponential factor(A)of the reactions simulated follow a long-established trend of those variable values displayed by shales and *** characteristics of the transformation fraction(TF)profiles(product generation window temperatures)of the simulated single reactions are compared to the TF profiles of recorded shale pyrograms generated by multiple reactions with different E-A values lying near the defined E-A *** similarities and differences are observed between the TF profile values of the two *** similarities support the spread of E-A values involved in shale pyrogram best *** differences are most likely explained by the complexity of the multiple kerogen first-order and second-order reactions contributing to the recorded shale pyrograms versus the simplicity and crispness of the single first-order reactions *** results also justify the validity of using the previously described“variable E-A pyrogram-fitting method”of multi-heating-rate shale pyrograms enabling optimizers to choose multiple reactions from an unlimited range of E-A *** contrast,further doubt is cast on the validity of the constant-A pyrogram-fitting method used by the Easy%Ro technique,in that a distribution of reactions with a single A value is unlikely to represent the complex variety of kerogen macerals observed in shale *** profiles generated by the variable E-A pyrogram-fitting method lie close to the established E-A trend and are likely to provide more realistic TF generation window temperatures than TF profiles generated by the constant-A pyrogram-fitting method.

关键词： transformation fraction profiles simulated S2 pyrograms multiple heating rates kerogen/shale kinetics S2 pyrogram fitting techniques kerogen petroleum research.

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垄断资本主义下的残疾与福利

国外理论动态 2021年第2期 121-128页

作者：大卫·马修斯(文) 王文彬(译) 曹立华(译) 英国威尔士兰德里洛学院辽宁大学公共基础学院辽宁大学新华国际商学院

残疾通常被视为一种生物学现象,而实际上,残疾是一种社会地位,是有缺陷的个人的身体功能与生产过程的要求之间不相容的表现和结果。文章试图通过分析残疾、身体、福利与资本主义之间的关系,进一步发展关于残疾的理论。同时,鉴于英国残... 详细信息

残疾通常被视为一种生物学现象,而实际上,残疾是一种社会地位,是有缺陷的个人的身体功能与生产过程的要求之间不相容的表现和结果。文章试图通过分析残疾、身体、福利与资本主义之间的关系,进一步发展关于残疾的理论。同时,鉴于英国残疾人政策近年来的变革,文章还评价了英国福利国家健全人和残疾人的评定标准,指出这种标准是为了满足垄断资本主义的需要而制定的,进而提出,只要资本主义仍然是占主导地位的生产方式,对残疾人的压迫就会继续下去。文章指出,在一种民主且能问责的经济制度中,工作将以人的需求为基础,社会的所有成员,无论是否有身体缺陷,都能够获得富足的物质生活,并以肯定其人性的方式参与社会的发展。只有对社会和经济进行民主式重组,才能使那些患有严重身体和认知障碍的人们远离贫穷和边缘化并享有有尊严、受尊重的生活。

关键词：垄断资本主义残疾福利残疾人政策

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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与安慰剂加他汀类相比，非诺贝特加他汀类药物的治疗方法可延缓病程10年的2型糖尿病患者的视网膜病变发展进程：控制糖尿病患者心血管危险行动（ACCORD）试验研究

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英国医学杂志中文版 2011年第5期14卷 306-307页

作者： david R matthews 马红雨（译）杨彩哲（校） Oxford Centre for Diabetes and Endocrinology Churchill HospitalOxfordOX3 71JUK 空军总医院临床检验中心空军总医院内分泌科

内容糖尿病性视网膜病变是糖尿病患者最常见的微血管并发症，无论在发达国家或发展中国家，它都是导致失明的首要原因。既往有研究显示强化血糖控制和严格的降压治疗可延缓视网膜病变的发展，而这一结果也得到了大量试验结果的验证。在... 详细信息

内容糖尿病性视网膜病变是糖尿病患者最常见的微血管并发症，无论在发达国家或发展中国家，它都是导致失明的首要原因。既往有研究显示强化血糖控制和严格的降压治疗可延缓视网膜病变的发展，而这一结果也得到了大量试验结果的验证。在视网膜病变的成因中血脂的作用并不是很明确。毫无疑问，降低血脂可以减少心血管事件的发生率，但对微血管病变的效果就不那么确定。非诺贝特干预降低糖尿病事件（FIELD）研究显示卅非诺贝特在糖尿病视网膜病变进展中的有益作用。

关键词：糖尿病性视网膜病变 2型糖尿病非诺贝特试验研究他汀类药物心血管危险患者治疗方法