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Frontiers of Materials Science 2011年第2期5卷 168-178页

作者： c. hEINZE c. SchWENK M. REThMEIER j. cARON Federal Institute for Materials Research and Testing Division 5.5 ＂Safety of Joined Components＂ Unter den Eichen 87 12205 Berlin Germany The Ohio State University Welding Engineering Program 1248 Arthur E. Adams Drive Columbus Ohio 43221 USA

The usage of continuous cooling transformation （ccT） diagrams in numerical welding simulations is state of the art. Nevertheless, specifications provide limits in chemical composition of materials which result in different ccT behavior and ccT diagrams, respectively. Therefore, it is necessary to analyze the influence of variations in ccT diagrams on the developing residual stresses. In the present paper, four ccT diagrams and their effect on numerical calculation of residual stresses are investigated for the widely used structural steel S355j. ＋ N welded by the gas metal arc welding （GMAW） process. Rather than performing an arbitrary adj.stment of ccT behavior, four j.stifiable data sets were used as input to the numerical calculation： data available in the Sysweld database, experimental data acquired through Gleeble dilatometry tests, and TTTIccT predictions calculated from the j.atPro and Edison Welding Institute （EWI） Virtual j.ining Portal software. The performed numerical analyses resulted in noticeable deviations in residual stresses considering the different ccT diagrams. Furthermore, possibilities to improve the prediction of distortions and residual stress based on ccT behavior are discussed.

关键词： welding simulation GMAW ccT sensitivity welding residual stress

PhYSIcAL SIMULATION OF cONTINUOUS ROLL cASTING PROcESS

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 505-511页

作者： L.h. Zhan j. Zhong X.Q. Li M.h. huang college of Electronical-Mechanical Engineering Central South University Changsha 410083China

A series of simulating experimental studies on the rheological behavior and its influential factors of aluminum alloy in continuous roll-casting process have been explored in this paper with a Gleeble-1500 Thermal-Mechanical Simulation Tester and a set of special clamp system. Relevant rheological rules in the process of coupling transient solidification and continuous deformation of roll-casting conditions are obtained. Experimental results indicate that four different characteristic stages exist in the whole rheological process, and relative constitutive models suitable for the given conditions of continuous roll casting process have been established through multivariable linear regression analysis of the experimental data.

关键词： continuous roll-casting rheological behavior physical simulation,constitutive relation

Ultrasonic-based surface patterning and interfacial reaction of ZrO_(2)ceramics

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j.urnal of Materials Science & Technology 2023年第24期155卷 202-210页

作者： h.j. Dong Z.L. Li X.G.Song j.c. Feng S.j. Wei j.h. Fu Y. Shi State Key Laboratory of Advanced Welding and j.ining Harbin Institute of Technology Harbin 150001 China Shandong Provincial Key Lab of Special Welding Technology Harbin Institute of Technology at Weihai Weihai 264209 China

We demonstrate a process to achieve selective surface metallization of ZrO_(2)ceramics using ultrasound technology in atmospheric environments at 350℃,which bestows good weldability of ZrO_(2)to achieve rapid and reliable connections with other metals as well as ceramic *** challenge is that brazing or diffusion welding processes to accomplish metallurgical connections for ZrO_(2) typically require holding at elevated temperatures for minutes to hours,while the selective ultrasonic metallization process requires only a few seconds of processing without the application of covering films or solder *** this study,the selected Sn-2Ti alloy could effectively wet and spread on ZrO_(2)substrate under ultrasonication,and continuous interphase layers were rapidly formed in situ between ZrO_(2)and *** bonding strength for the ZrO_(2)/Sn-2Ti interface was well established with the highest shear strength of 37.1 MPa,and the fracture location occurred at the filler *** interfacial reaction layer thickened remarkably with the prolongation of sonication,accompanied by the partial crystallization of amorphous TiO and the formation of irregularly striped Ti_(11.31)Sn_(3)O_(10)nanocrystals.

关键词： Selective ultrasonic metallization Zirconia surface patterning Low temperature connection Sono-oxidation Interfacial reaction

DAMPING BEhAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND ThE DAMPING MEchANISM

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 223-227页

作者： Z.M. Zhang c.j. Xu j.c. Wang h.Z. Liu School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 Ghina State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 Ghina

Ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing （EcAP） and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q^-1 with the ambient value being 9.8×10^-3 at 1.0hz when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points.

关键词： EcAP ultrafine grain damping capacity aluminum alloy

j.ffery-hamel flow of non-Newtonian fluid with nonlinear viscosity and wall friction

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 815-830页

作者： j. NAGLER Department of Fluid Mechanics and heat Transfer Faculty of Engineering Tel-Aviv University Ramat-Aviv 69978 Israel

A j.ffery-hamel （j.h） flow model of the non-Newtonian fluid type inside a convergent wedge （inclined walls） with a wall friction is derived by a nonlinear ordinary differential equation with appropriate boundary conditions based on similarity relationships. Unlike the usual power law model, this paper develops nonlinear viscosity based only on a tangential coordinate function due to the radial geometry shape. Two kinds of solutions are developed, i.e., analytical and semi-analytical （numerical） solutions with suitable assumptions. As a result of the parametric examination, it has been found that the Newtonian normalized velocity gradually decreases with the tangential direction progress. Also, an increase in the friction coefficient leads to a decrease in the normalized Newtonian velocity profile values. however, an increase in the Reynolds number causes an increase in the normalized velocity function values. Additionally, for the small values of wedge semi-angle, the present solutions are in good agreement with the previous results in the literature.

关键词： j.ffery-hamel (j.h) flow slip condition non-Newtonian fluid friction,nonlinear viscosity analytical solution numerical solution approximate solution

Shifting equilibriums in Alzheimer’s disease: the complex roles of microglia in neuroinflammation, neuronal survival and neurogenesis

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Neural Regeneration Research 2020年第7期15卷 1208-1219页

作者： Sophie c. Gray Kerri j. Kinghorn Nathaniel S. Woodling Institute of healthy Ageing and Department of Genetics Evolution and Environment University College London

Alzheimer's disease is the leading cause of *** increased prevalence in developed countries,due to the sharp rise in ageing populations,presents one of the costliest challenges to modern *** order to find disease-modifying therapies to confront this challenge,a more complete understanding of the pathogenesis of Alzheimer's disease is *** studies have revealed increasing evidence for the roles played by microglia,the resident innate immune system cells of the *** the well-established roles of microglia in reacting to pathogens and inflammatory stimuli,there is now a growing literature describing both protective and detrimental effects for individual cytokines and chemokines produced by microglia in Alzheimer's disease.A smaller but increasing number of studies have also addressed the divergent roles played by microglial neurotrophic and neurogenic factors,and how their perturbation may play a key role in the pathogenesis of Alzheimer's *** we review recent findings on the roles played by microglia in neuroinflammation,neuronal survival and neurogenesis in Alzheimer's *** each case,landmark studies have provided evidence for the divergent ways in which microglia can either promote neuronal function and survival,or perturb neuronal function,leading to cell *** many cases,the secreted molecules of microglia can lead to divergent effects depending on the magnitude and context of microglial *** suggests that microglial functions must be maintained in a fine equilibrium,in order to support healthy neuronal function,and that the cellular microenvironment in the Alzheimer's disease brain disrupts this fine balance,leading to ***,an understanding of microglial homeostasis,both in health and across the traj.ctory of the disease state,will improve our understanding of the pathogenic mechanisms underlying Alzheimer's disease,and will hopefully lead to the development of microglial-base

关键词： adult neurogenesis Alzheimer's disease IGF-1 microglia neuroinflammation Trem2

AN AccURATE NUMERIcAL SOLUTION OF A TWO DIMENSIONAL hEAT TRANSFER PROBLEM WITh A PARABOLIc BOUNDARY LAYER

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j.urnal of computational Mathematics 1998年第1期16卷 27-39页

作者： c.clavero j.j.h.Miller E.O'Riordan G.I.Shishkin Universidad de Zaragoza 西班牙 Trinity college 爱尔兰 Dublin city University 爱尔兰 Institute of Mathematics and Mechanics 俄罗斯

A singularly perturbed linear convection-diffusion problem for heat transfer in two dimensions with a parabolic boundary layer is solved numerically The numerical method consists of a special piecewise uniform mesh condensing in a neighbourhood of the parabolic layer and a standard finite difference operator satisfying a discrete maximum principle. The numerical computations demonstrate numerically that the method is epsilon-uniform in the sense that the Fate of convergence and error constant of the method are independent of the singular perturbation parameter epsilon. This means that no matter how small the singular perturbation parameter epsilon is, the numerical method produces solutions with guaranteed accuracy depending solely on the number of mesh points used.

关键词： linear convection-diffusion parabolic layer piecewise uniform mesh finite difference

combinatorial therapies for spinal cord inj.ry repair

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Neural Regeneration Research 2025年第5期20卷 1293-1308页

作者： carla S.Sousa Andreia Monteiro António j.Salgado Nuno A.Silva Life and health Sciences Research Institute(IcVS) School of MedicineUniversity of MinhoCampus de Gualtar-gualtarBragaPortugal IcVS/3B’s Associate Lab PT Government Associated LabCampus de Gualtar-gualtarBragaPortugal

Spinal cord inj.ries have profound detrimental effects on individuals, regardless of whether they are caused by trauma or non-traumatic events. The compromised regeneration of the spinal cord is primarily attributed to damaged neurons, inhibitory molecules, dysfunctional immune response, and glial scarring. Unfortunately, currently, there are no effective treatments available that can fully repair the spinal cord and improve functional outcomes. Nevertheless, numerous pre-clinical approaches have been studied for spinal cord inj.ry recovery, including using biomaterials, cells, drugs, or technological-based strategies. combinatorial treatments, which target various aspects of spinal cord inj.ry pathophysiology, have been extensively tested in the last decade. These approaches aim to synergistically enhance repair processes by addressing various obstacles faced during spinal cord regeneration. Thus, this review intends to provide scientists and clinicians with an overview of pre-clinical combinatorial approaches that have been developed toward the solution of spinal cord regeneration as well as update the current knowledge about spinal cord inj.ry pathophysiology with an emphasis on the current clinical management.

关键词： electric stimulation neural tissue regeneration neuroprotection polytherapy spinal cord inj.ry

Post-occupancy evaluation of a restored industrial building： A contemporary art and design gallery in Mexico

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Frontiers of Architectural Research 2015年第4期4卷 330-340页

作者： j. Mundo-hernandez M.c. Valerdi-Nochebuena j. Sosa-Oliver Department of Architecture Universidad de las Americas Puebla Puebla 72810 Mexico Faculty Of Architecture BenemOrita Universidad Aut6noma de Puebla Puebla 72000 Mexico

This paper presents the results obtained from a post-occupancy evaluation （POE） study conducted in an old fabric building called ＂La VToleta＂. This structure has been recently converted into a contemporary art *** Violeta is located in Puebia city, Mexico. The buiidieg dates from the beginning of the 19th century; it was buitt and used as a textite factory until the first decades of the 20th century. This POE study aims to assess the new use of the buildieg from the users＇ point of view. Methodology involves historical research of the building, analysis of the conversion strategy, watkthrough investigation, and a user survey. Questions regarding the re-utilization strategy used in the building and its current use are inctuded in the survey, such as ＂hew do people perceive the space regarding its functionality, accessibility, and comfort？＂ ALthough the re-utitization process destroyed several historic elements, the re-use of old industrial spaces that otherwise would be obsotete and disused seems pertinent. Developing stoatl renovation proj.cts as part of an integrat and wider proj.ct seems feasible. Users perceive the buiidinR as comfortabte but not property advertised as an art gallery, and its location is difficult to find.

关键词： Industrial heritage Users' perception Art gallery Post-occupancyevatuation

Effect of pre-deformation on microstructure and mechanical properties of WE43 magnesium alloy II: Aging at 250 and 300℃

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j.urnal of Magnesium and Alloys 2020年第1期8卷 103-110页

作者： Y.h.Kang Z.h.huang S.c.Wang h.Yan R.S.chen j.c.huang Guangdong-hong Kong j.int Research and Development center on Advanced Manufacturing Technology for Light Alloys Guangdong Institute of Materials and ProcessingGuangzhou 510650China Institute of Metal Research chinese Academy of Sciences Shenyang 110016China hong Kong Institute for Advanced Study Department of Materials Science and EngineeringCity University of Hong KongHong KongChina

In this work,the microstructural evolution and mechanical properties of a pre-deformed WE43 magnesium alloy when aged at 250 and 300℃ were further *** is found that the abundant deformation twins introduced by pre-deformation were maintained within the alloy during the aging *** particles formed at the twin boundaries and coarsened with aging time,especially at 300℃.When peak-aged at 250℃,the fine metastable β'''and β' precipitates formed in the un-deformed alloy have been transformed into relatively large β1 and β precipitates by the *** peak-aged at 300℃,the pre-deformation obviously refined the β *** properties indicate that pre-deformation can increase the yield strength by 19MPa and 54MPa for the peak-aged alloy at 250℃ and 300℃,respectively,and will not obviously deteriorate the tensile elongations.

关键词： WE43 magnesium alloy Pre-deformation Aging Microstructure Mechanical properties