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Plastic Effect on the Sliding Inception Bet ween a Cylinder and a Rigid Flat

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Acta Mechanica Solida Sinica 2019年第1期32卷 1-16页

作者： S.Zhang J.huan h.Song X.Liu Y.G.Wei LNM Institute of MechanicsChinese Academy of SciencesBeijing 100190China Department of Mechanical Engineering Johns Hopkins UniversityBaltimoreMD 21218USA College of Engineering Peking UniversityBeijing 100871China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The effec ts of mat erial plasticity and local slip on the sliding inception of asperity are studied in the present ***,a semi-analytical solution is derived under the full-stick condition to analyze the effect of material plasticity on sliding ***,a friction model with contact stiffness criterion is proposed to study the cases from partial-slip condition to full-stick *** element simulations with the provided model are used to present the friction *** friction coefficient of full-s tick interface converges at a st able value,approxima tely *** saturation appears as the normalized contact interference u*is larger than 3.A transition mechanism from slip-dominated to yield-dominated takes place in the sliding *** simulation results are compared with the semi-analytical solution.

关键词： Mat erial yielding Local slip Contact stiffness criterion Finite element simulation

Neurorestorative Effects of Constraint-Induced Movement Therapy after Stroke: An Integrative Review

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Neuroscience & Medicine 2013年第4期4卷 253-262页

作者： Marina lucas Pedro Ribeiro Mauricio Cagy Silmar Teixeira Fernanda Chaves Diana Carvalho Caroline Peressutti Sérgio Machado Juliana Bittencourt Bruna Velasques Roberto Piedade Brain Mapping and Sensory Motor Integration Institute of Psychiatry of Federal University of Rio de Janeiro (IPUB/UFRJ) Rio de Janeiro Brazil Brain Mapping and Sensory Motor Integration Institute of Psychiatry of Federal University of Rio de Janeiro (IPUB/UFRJ) Rio de Janeiro Brazil Physiotherapy Laboratory Veiga de Almeida University (UVA) Rio de Janeiro Brazil Physiotherapy Department Piquet Carneiro Policlinic State University of Rio de Janeiro (UERJ) Rio de Janeiro Brazil Brain Mapping and Sensory Motor Integration Institute of Psychiatry of Federal University of Rio de Janeiro (IPUB/UFRJ) Rio de Janeiro Brazil School of Physical Education Bioscience Department Federal University of Rio de Janeiro (EEFD/UFRJ) Rio de Janeiro Brazil Institute of Applied Neuroscience (INA) Rio de Janeiro Brazil Brain Mapping and Sensory Motor Integration Institute of Psychiatry of Federal University of Rio de Janeiro (IPUB/UFRJ) Rio de Janeiro Brazil Institute of Applied Neuroscience (INA) Rio de Janeiro Brazil Division of Epidemiology and Biostatistic Institute of Health Community Federal Fluminense University (UFF) Rio de Janeiro Brazil Laboratory of Panic and Respiration Federal University of Rio de Janeiro (UFRJ) Rio de Janeiro Brazil Physical Activity Neuroscience Laboratory Salgado de Oliveira University Rio de Janeiro Brazil

Stroke has been considered as one of the main causes of death and of motor and cognitive sequels. Especially, many patients with upper limb hemiparesis improved their motor action and showed meaningful cortical changes after treatment with constraint-induced movement therapy. Therefore, this review aims to verify the literature about neuroimaging and behavioral evidences in the cortical reorganization through the use of the constraint-induced movement therapy. So, we conducted the literature research in indexed journals from many databases like Pubmed, Medline, Cochrane Database, Lilacs and Scielo. We concluded that the behavioral and neuroimaging studies using traditional and modified constraint-induced movement therapy promote cortical reorganization.

关键词： Stroke Constraint-Induced-Movement-Therapy Neuroplasticity Cerebral Reorganization

Expression of Egr-1 in the liver of mice following hemorrhagic shock and resuscitation

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Journal of Medical Colleges of PLA(China) 2005年第2期20卷 79-84页

作者：梅建民 timothy R.Billiar 于聪慧 David J.Gallo 杨荣华 Department of hepatobiliary Surgery General Hospital of Beijing Military Command Department of Surgery University of Pittsburgh School of Medicine Pittsburgh Pennsylvania 15213 U.S.A Department of Surgery University of Pittsburgh School of MedicinePittsburghPennsylvania 15213 U.S.A

Objective: To investigate the expression of early growth response gene-1(Egr-1) in the liver following hemorrhagic shock with or without resuscitation(hS or hSR). Methods: Mice were subjected to hS or *** expression of Egr-1 mRNA was detected by Northern *** binding activity of the Egr-1 protein in liver nuclear extracts(NE) was determined by electrophoretic mobility shift assay(EMSA).Western blot analysis was used to assess the induction of Egr-1 protein in the liver tissue,cytoplasma and NE. Results: Egr-1 mRNA was strongly expressed as early as 1 h after hS,and its level was decreased in the following 2.5 h but still higher than that in 1 h hS *** Egr-1 DNA binding activity elevated in the liver NE of 2.5 h hS group and 2.5 h hS + 4 h R group,so did the Egr-1 protein in the liver and the liver NE of the same two ***,the maximal Egr-1 protein expression was found in the cytoplasma of liver following 2.5 h hS. Conclusion: Our data suggest that both Egr-1 mRNA and protein are strongly elevated and the binding activity of Egr-1 to its cognate DNA site is increased in the liver following hSR,indicating the increases of Egr-1 transcriptional and translational *** study provides evidence that Egr-1 gene is activated in the liver during hS and hSR.

关键词： early growth response gene-1(Egr-1) livers hemorrhagic shock resuscitation

Synthesis of self-assembled nanorod vanadium oxide bundles by sonochemical treatment

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Journal of Natural Gas Chemistry 2009年第3期18卷 312-318页

作者： Y.h.Taufiq-Yap Y.C.Wong Z.Zainal M.Z.hussein Centre of Excellence for Catalysis Science and Technology Faculty of ScienceUniversiti Putra Malaysia Department of Chemistry Faculty of ScienceUniversiti Putra Malaysia

Self-assembled nanorod of vanadium oxide bundles were synthesized by treating bulk V2O5 with high intensity sonochemical technique. The synthesized materials were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM） and temperature-programmed reduction （TPR） in h2. Catalytic behaviour of the materials over anaerobic n-butane oxidation was studied through temperature-programmed reaction （TPRn）. Catalytic evaluation of the sonochemical treated V2O5 products was also studied on microreactor. XRD patterns of all the vanadium samples were perfectly indexed to V2O5. The morphologies of the nanorod vanadium oxides as shown in SEM and TEM depended on the duration of the ultrasound irradiation. Prolonging the ultrasound irradiation duration resulted in materials with uniform, well defined shapes and surface structures and smaller size of nanorod vanadium oxide bundles. h2-TPR profiles showed that larger amount of oxygen species were removed from the nanorod V2O5 compared to the bulk. Furthermore, the nanorod vanadium oxide bundles, which were produced after 90, 120 and 180 min of sonochemical treatment, showed an additional reduction peak at lower temperature （-850 K）, suggesting the presence of some highly active oxygen species. TPRn in n-butane/he over these materials showed that the nanorod V2O5 with highly active oxygen species showed markedly higher activity than the bulk material, which was further proven by catalytic oxidation of n-butane.

关键词： nanorod vanadium oxide sonochemical treatment butane oxidation

Reactivity of Nanostructured MnO_2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent

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Journal of Materials Science & Technology 2011年第7期27卷 585-593页

作者： L.Benhaddad L.Makhloufi B.Messaoudi1 K.Rahmouni h.Takenouti Laboratoire de Technologie des Matériaux et Génie des Procédés (LTMGP) Département de Génie des Procédés. Université A. MiraRoute de Targa Ouzemmour06000 BéjaiaAlgeria UPR 15 du CNRS LISE-Laboratoire Interfaces et Systèmes Electrochimiques UPMC University Paris 06Case 133 4 place Jussieu 75252 Paris Cedex 05 France UPR 15 du CNRS LISE-Laboratoire Interfaces et Systèmes Electrochimiques UPMC University Paris 06Case 1334 place Jussieu 75252 Paris Cedex 05France

The synthesis of MnO2 powders by hydrothermal method with different oxidizing agents has been successfully achieved. The characterizations by scanning electron microscopy, energy-dispersive X-ray analyses, transmission electron microscopy, and X-ray diffraction techniques confirm the synthesis of nanostructured γ-MnO2 powders. The electrochemical reactivity of these powders in 1 mol/l KOh is investigated by cyclic voltammetry and electrochemical impedance spectroscopy （EIS） by using microcavity electrode. The results reveal that the MnO2 synthesized with Na2S2O8 shows the highest electrochemical reactivity in the test medium. This is due both to its large expanded surface area and its crystallographic variety γ-MnO2 formed in the matrix of ramsdellite, which is largely used as cathodic material for primary batteries. however, the presence of pyrolusite in the structure of γ-MnO2 synthesized with （Nh4）2S2O8 decreases its electrochemical reactivity due to its narrow 1×1 size tunnel, which hinders the protons insertion.

关键词： hydrothermal processing Electrochemical impedance spectroscopy (EIS) Cyclic voltammetry X-ray diffraction γ-MnO2

Physical properties of spray deposited CdTe thin films:PEC performance

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Journal of Semiconductors 2011年第3期32卷 10-16页

作者： V.M.Nikale S.S.Shinde C.h.Bhosale K.Y.Rajpure Electrochemical Materials Laboratory Department of PhysicsShivaji University

p-CdTe thin films were prepared by spray pyrolysis under different ambient conditions and characterized using photoelectrochemical（PEC）,X-ray diffraction（XRD）,scanning electron microscopy,energy-dispersive analysis by X-ray（EDAX）,and optical transmission *** different preparative parameters viz solution ph, solution quantity,substrate temperature and solution concentration have been optimized by the PEC technique in order to get good-quality photosensitive *** analysis shows the polycrystalline nature of the film,having cubic structure with strong（111） *** reveal that grains are uniformly distributed over the surface of the substrate indicating the well-defined growth of polycrystalline CdTe thin *** EDAX study for the sample deposited at optimized preparative parameters shows the nearly stoichiometric Cd：Te *** absorption shows the presence of direct transition with band gap energy of 1.5 *** films exhibit the highest photocurrent of 2.3 mA,a photovoltage of 462 mV,a 0.48 fill factor and 3.4%efficiency for the optimized preparative parameters.

关键词： CdTe PEC temperature concentration structure morphology composition optical

Analytical Investigation of Prior Austenite Grain Size Dependence of Low Temperature Toughness in Steel Weld Metal

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Journal of Materials Science & Technology 2012年第3期28卷 241-248页

作者： X.F. Zhang P. hall h. Terasak M. Sato Y. Komizo Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki Osaka 56%0047 Japan Technical Development Department Welding Business Kobe Steel Ltd. 100-1 Miyamae Fujisawa Kanagawa 251- 8551 Japan

Prior austenite grain size dependence of the low temperature impact toughness has been addressed in the bainitic weld metals by in situ ***,decreasing the grain size is the only approach by which both the strength and the toughness of a steel are ***,low carbon bainitic steel with small grain size shows a weakening of the low temperature impact toughness in this *** direct tracking of the morphological evolution during phase transformation,it is found that large austenite grain size dominates the nucleation of intragranular acicular ferrite,whereas small austenite grain size leads to grain boundary nucleation of *** kinetics information will contribute to meet the increasing low temperature toughness requirement of weld metals for the storage tanks and offshore structures.

关键词： In situ observation Prior austenite grain size Low temperature toughness Intragranular nucleation Grain boundary nucleation

Suction Performance and Internal Flow of a 2-Bladed helical Inducer with Inlet Asymmetric Plate

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Journal of Thermal Science 2013年第5期22卷 395-403页

作者： S.Watanabe Y.Uchinono K.Ishizaka A.Furukawa J.-h.Kim Department of Mechanical Engineering Kyushu University744 Motooka Nishi-ku Fukuoka 819-0395 Japan Graduate School of Engineering Kyushu University744 Motooka Nishi-ku Fukuoka 819-0395 Japan Oita National College of Technology hyosung Goodsprings Co. Ltd.Korea

It has been found in our past studies that the installation of asymmetric plate at the inlet of inducer is effective for the suppression of cavitation surge *** the present study,the suction performance of 2-bladed helical inducer with an inlet asymmetric plate is experimentally *** is observed that the suction performance in large flow rate conditions is not significantly influenced by the asymmetric plate,whereas the head of inducer with the asymmetric plate increases just before the head breakdown in partial flow *** understand the mechanism of this additional head,the flow measurements and the numerical simulations are carried *** is found that the circumferential component of absolute velocity at the exit of inducer slightly increases with the development of cavitation in both cases with and without the inlet asymmetric plate,indicating the increase of the theoretical *** theoretical head increase with the inlet asymmetric plate is also confirmed by the unsteady numerical simulations,suggesting that the additional head is achieved through the increase of the theoretical head with the change of the exiting flow from the inducer associated with some amount of cavitation.

关键词： Inducer Cavitation Suction performance Internal flow Inlet asymmetric plate

hot Cracking in AZ31 and AZ61 Magnesium Alloy

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Journal of Materials Science & Technology 2011年第7期27卷 633-640页

作者： C.J. huang C.M. Cheng C.P. Chou F.h. Chen Department of Mechanical Engineering National Chiao Tung University Hsinchu 300 Taiwan China Department of Industrial Education National Taiwan Normal University Taipei 106 Taiwan China

This paper examined the impact of the number of thermal cycles and augmented strain on hot cracking in AZ31 and AZ61 magnesium alloy. Statistical analyses were performed. Following observation using a scanning electron microscope （SEM）, an energy dispersive spectrometer （EDS） was used for component analysis. Results showed that Al content in magnesium alloy has an effect on hot cracking susceptibility. In addition, the nonequilibrium solidification process produced segregation in Al content, causing higher liquid Mg-alloy rich Al content at grain boundaries, and resulting into liquefied grain boundaries of partially melted zone （PMZ）. In summary, under multiple thermal cycles AZ61 produced serious liquation cracking. AZ61 has higher （6 wt%） Al content and produced much liquefied Mg17Al12 at grain boundaries under multiple thermal cycles. The liquefied Mg17Al12 were pulled apart and hot cracks formed at weld metal hAZ due to the augmented strain. Since AZ31 had half the Al content of AZ61, its hot-cracking susceptibility was lower than AZ61. In addition, AZ61 showed longer total crack length （TCL） in one thermal cycle compared to that in three thermal cycles. This phenomenon was possibly due to high-temperature gasification of Al during the welding process, which resulted in lower overall Al content. Consequently, shorter hot cracks exhibited in three thermal cycles. It was found the Al content of AZ31 and AZ61 can be used to assess the hot-cracking susceptibility.

关键词： Varestraint test Thermal cycles hot-cracking susceptibility Gas tungsten arc welding (GTAW) AZ31 AZ61