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Inhibiting effect of I-phase formation on the plastic instability of the duplex structured Mg-8li-6Zn-1.2y(in wt.%)alloy

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Journal of Magnesium and Alloys 2023年第6期11卷 2196-2204页

作者： B.J.Wang D.k.Xu X.Q.Zhuang l.y.Sheng School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China k.y.laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Peking University Shenzhen InstituteShenzhen Key Lab Human Tissue Regenerate&RepairShenzhen 518057China

In this work,the tensile behaviors of Mg-8%li and Mg-8%li-6%Zn-1.2%y alloys at ambient temperature were investigated and *** revealed that the plastic instability of Mg-8%li alloy was quite remarkable and the variation range of serrated flowing stress can reach5 *** the Mg-8%li-6%Zn-1.2%y alloy,the formation of I-phase(Mg_(3)Zn_(6)y)can simultaneously enhance the tensile strength and eliminate the plastic instability phenomenon,whilst its ductility was *** in-situ tensile tests revealed that for the Mg-8%li alloy,the severity and number of slip traces present in bothα-Mg andβ-li matrix phases increased remarkably with the applied tensile ***,slip traces were quite fine inβ-li matrix phase and could be clearly observed when the applied tensile strain exceeded 18%.Due to the incompatibility of plastic deformation occurred in two matrix phases,the induced strain concentration atα-Mg/β-li interfaces caused their subsequent *** the Mg-8%-6%Zn-1.2%y alloy,the I-phase distributed atα-Mg/β-li interfaces suppressed the plastic deformation ofα-Mg matrix phase and the tensile strain was dominated by theβ-li matrix phase,resulting in the disappearance of plastic ***,the plastic strain would preferentially concentrate at I-phase/β-li interfaces and subsequently induced the cracking of I-phase.

关键词： Mg-li alloys Microstructure Plastic deformation Basal slip Cracking

Exercise preconditioning alleviates ischemia-induced memory deficits by increasing circulating adiponectin

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Neural Regeneration Research 2025年第5期20卷 1445-1454页

作者： Meifeng Zheng Borui Zhang Sonata S y yau kwok-Fai So li Zhang Haining Ou Department of Rehabilitation Medicine Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina Department of Rehabilitation Medicine The Fifth Clinical College of Guangzhou Medical UniversityGuangzhouGuangdong ProvinceChina k.y.laboratory of CNS Regeneration(Ministry of Education) Guangdong-Hong Kong-Macao Institute of CNS RegenerationJinan UniversityGuangzhouGuangdong ProvinceChina Department of Rehabilitation Sciences The Hong Kong Polytechnic UniversityHong Kong Special Administrative RegionChina State k.y.laboratory of Brain and Cognitive Science Li Ka Shing Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina Center for Exercise and Brain Science School of PsychologyShanghai University of SportShanghaiChina Neuroscience and Neurorehabilitation Institute University of Health and Rehabilitation SciencesQingdaoShandong ProvinceChina

Cerebral ischemia is a major health risk that requires preventive approaches in addition to drug *** exercise enhances neurogenesis and synaptogenesis,and has been widely used for functional rehabilitation after *** this study,we determined whether exercise training before disease onset can alleviate the severity of cerebral *** also examined the role of exercise-induced circulating factors in these *** mice were subjected to 14 days of treadmill exercise training before surgery for middle cerebral artery *** found that this exercise pre-conditioning strategy effectively attenuated brain infarct area,inhibited gliogenesis,protected synaptic proteins,and improved novel object and spatial memory *** analysis showed that circulating adiponectin plays a critical role in these preventive effects of *** activation of adiponectin receptors by Adipo Ron mimicked the effects of exercise,while inhibiting receptor activation abolished the exercise *** summary,our results suggest a crucial role of circulating adiponectin in the effects of exercise pre-conditioning in protecting against cerebral ischemia and supporting the health benefits of exercise.

关键词： adiponectin cerebral ischemia exercise pre-conditioning hippocampus memory function middle cerebral artery occlusion prefrontal cortex synaptic proteins treadmill exercise

Microstructural characteristics and mechanical properties of the hot extruded Mg-Zn-y-Nd alloys

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Journal of Materials Science & Technology 2021年第1期60卷 44-55页

作者： B.N.Du Z.y.Hu l.y.Sheng D.k.Xu y.X.Qiao B.J.Wang J.Wang y.F.Zheng T.F.Xi Shenzhen Institute Peking UniversityShenzhen 518057China k.y.laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Jiangsu University of Science and Technology Zhenjiang 212003China Shenzhen yezhan Electronics Co. LtdShenzhen 518110China

A new type of Mg-Zn-y-Nd alloy for degradable orthopedic implants was *** the present study,the Zn and y content was adjusted and their influences on the microstructures and mechanical behaviors were discussed in *** results showed that the as-extruded Mg-Zn-y-Nd alloys are mainly composed of fine dynamic recrystallized grains(DRXed grains),la rge unDRXed grains and linearly distributed secondary *** cha nge of Zn content exerts little influence on the grain structure of the extruded Mg-Zn-y-Nd alloy,while the increase of y content would hinder the dynamic recrystallization process and the growth of the DRXed grains,thus the size and volume fraction of the equiaxed DRXed grains *** tensile and compressive properties are very little affected by Zn content because of the similar grain *** y content increases,the tensile yield strength(TyS) and ultimate strength(TUS) increase while the elongation decreases,this is caused by a combined strengthening effect of grain refinement,texture,precipitation and *** compressive yield strength(CyS) and ultimate strength(CUS) of Mg-Zn-y-Nd alloy with diffe rent y content exhibit a similar tendency as the tensile test.

关键词： Mg-Zn-y-Nd alloy Microstructure Tensile properties Compressive properties Basal texture Twin

Gene therapy for spinal muscular atrophy:perspectives on the possibility of optimizing SMN1 delivery to correct all neurological and systemic perturbations

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Neural Regeneration Research 2025年第7期20卷 2011-2012页

作者： Sharon J.Brown Rafael J.yáñez-Muñoz Heidi R.Fuller School of Pharmacy and Bioengineering Keele UniversityKeeleUK Wolfson Center for Inherited Neuromuscular Disease TORCH BuildingRJAH Orthopaedic HospitalOswestryUK *** Center of Gene and Cell TherapyDepartment of Biological SciencesSchool of Life Sciences and the EnvironmentRoyal Holloway University of LondonEghamUK

Spinal muscular atrophy(SMA)is a genetic condition that results in selective lower motor neuron loss with concomitant muscle weakness and *** genetic cause of SMA was understood in 1995 when loss or impairment of the survival motor neuron 1(SMN1)gene was identified as the main contributing factor(lefebvre et al.,1995).This,in combination with the discovery that humans have a“back-up”gene,SMN2,which can produce low levels(approximately 10%)of the full-length functional SMN protein,has led to the generation of SMA-specific gene *** was traditionally classified according to age of symptom onset and developmental milestones achieved,with life expectancy and severity varying between ***,SMN2 copy number is used as a proxy for the prediction of disease severity,with higher SMN2 copy number typically being associated with reduced severity of SMA,although this relationship is not absolute:some individuals with low SMN2 copy number have less severe SMA phenotypes and vice ***,the etiology of SMA is further complicated by other factors,such as non-typical nucleotide variants and SMN2-independent modifiers of disease severity.

关键词： atrophy traditionally absolute

Plastic deformation behavior of Mg97Zn1y2 extruded alloys

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Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1259-1268页

作者： k.HAGIHARA A.kINOSHITA y.SUGINO M.yAMASAkI y.kAWAMURA H.y.yASUDA y.UMAkOSHI Division of Materials and Manufacturing Science Graduate School of EngineeringOsaka University2-1Yamada-okaSuitaOsaka 565-0871Japan Department of Materials Science Kumamoto University2-39-1KurokamiKumamoto 860-8555Japan National Institute for Materials Science 1-2-1SengenTsukubaIbaraki 305-0047Japan

The mechanical properties of the Mg97Znly2 extruded alloy containing the long-period stacking ordered phase, the so-called lPSO-phase, with a volume fraction of 24%-25%, were examined by compression tests and cyclic tension-compression deformation tests. The plastic behavior of the extruded alloys with compositions of Mg99.2Zn0.2y0.6 and Mg89Zn4y7 （molar fraction, %）, which were almost the same compositions of Mg matrix phase and lPSO phase in Mg97Zn1y2 Mg/lPSO two-phase alloy, respectively, were also prepared. By comparing their mechanical properties, the strengthening mechanisms operating in the Mg97Zn1 y2 extruded alloy were discussed. Existence of the lPSO-phase strongly enhanced the refinement of Mg matrix grain size during extrusion, which led to a large increment of the strength of alloy. In addition, the lPSO-phases, which were aligned along the extrusion direction in Mg97Zn1y2 extruded alloy, acted as hardening phases, just like reinforced fibers.

关键词： plastic deformation yield stress lPSO-phase dislocation twinning

Suppressing Effect of Heat Treatment on the Portevin–le Chatelier Phenomenon of Mg–4%li–6%Zn–1.2%y Alloy

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Journal of Materials Science & Technology 2016年第12期32卷 1232-1238页

作者： C.Q.li D.k.Xu B.J.Wang l.y.Sheng E.H.Han School of Materials Science and Engineering Northeastern University Shenyang 110819 China k.y.laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Environmental Corrosion Center Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Shenzhen Institute Shenzhen Key Lab Human Tissue Regenerate and Repair Peking University Shenzhen 518057 China

Microstructural evolution and Portevin-le Chatelier（PlC） phenomenon of the as-extruded Mg-4%li-6%Zn-1.2%y alloy before and after heat treatment have been *** has been demonstrated that for the as-extruded and solid solution treated（T4） samples,the PlC phenomenon could be obviously observed on tensile stress-strain ***,the PlC phenomenon in T4 samples was more salient than that in the as-extruded condition,suggesting that the occurrence of PlC phenomenon was closely related to the super-saturation degree of solute atoms in the *** most of solute atoms were consumed for the formation of Mg Zn precipitates（β1′ and a little of β2′） during the subsequent ageing treatment（T6）,the PlC phenomenon of T6 samples was ***,due to the pinning effect of the formed Mg Zn precipitates on mobile dislocations,the tensile strength of T6 samples was relatively higher than those of the other two conditions.

关键词： Mg-li alloy Heat treatment Portevin-le Chatelier (PlC) effect Precipitates

Different effects of economic and structural performance indexes on model construction of structural topology optimization

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Acta Mechanica Sinica 2015年第5期31卷 777-788页

作者： G.l.yi y.k.Sui College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology Department of Mechanical and Aerospace Engineering Seoul National University

The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this *** influences of their different roles in model construction of structural topology optimization are also ***,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint（MCVC）model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint（MWDC）model,are *** on a comparison of numerical example results,the conclusions can be summarized as follows：（1）under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;（2）the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;（3）constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering.

关键词： Economic index Performance index Structural topology optimization models MCVC model MWDC model Safety and economy

Effects of annealing treatment on microstructure and tensile behavior of the Mg-Zn-y-Nd alloy

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Journal of Magnesium and Alloys 2020年第3期8卷 601-613页

作者： l.y.Sheng B.N.Du Z.y.Hu y.X.Qiao Z.P.Xiao B.J.Wang D.k.Xu y.F.Zheng T.F.Xi Shenzhen Institute Peking UniversityShenzhen 518057China Jiangsu University of Science and Technology Zhenjiang 212003China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China dShenzhen yezhan Electronics Co. LtdShenzhen 518110China

In the present study,the Mg-4Zn-0.6y-0.5Nd alloy was hot extruded and annealed at 200℃,225℃ and 250℃ for different time to optimize microstructure and mechanical *** results exhibit that the dual-size grain structure and linearly distributed secondary phase are the main feature of the as-extruded Mg-Zn-y-Nd alloy,which can be described as the elongated grain is surrounded by the fine equiaxed ***,the as-extruded alloy shows strong{011^(-)0}fiber texture feature,especially for the large elongated *** annealing treatment results in static recrystallization,which increases fine equiaxed grains but decreases large elongated *** addition,the equiaxed grains formed during the annealing treatment demonstrate relative random orientations,which weaken the{011^(-)0}fiber texture of the ***,during the annealing at 225℃and 250℃,the extension twins begin to form in the alloy and weaken the{011^(-)0}fiber texture of the alloy *** annealing treatment has little influence on the linearly distributed secondary phase but promotes the coarsening of small precipitates at 250℃.The annealing treatment could increase the yield and ultimate strength,but the elongation decreases,especially at higher *** a variation can be ascribed to the evolution of texture,grain structure,twinning and precipitation during the annealing treatment.

关键词： Annealing treatment Mg-Zn-y-Nd alloy Microstructure Tensile property

Combustion modeling in a model combustor

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航空动力学报 2007年第5期22卷 694-703页

作者： l.y.Jiang I.Campbell k.Su Institute for Aerospace Research National ResearchCouncil Canada OttawaONK1A 0R6Canada Department of Mechanical Automotiveand Materials EngineeringUniversity of WindsorWindsorONN9B 3P4Canada

The flow-field of a propane-air diffusion flame combustor with interior and exterior conjugate heat transfers was numerically *** obtained from four combustion models,combined with the re-normalization group(RNG) k-ε turbulence model,discrete ordinates radiation model and enhanced wall treatment are presented and *** results are compared with a comprehensive database obtained from a series of experimental *** flow patterns and the recirculation zone length in the combustion chamber are accurately predicted,and the mean axial velocities are in fairly good agreement with the experimental data,particularly at downstream sections for all four combustion *** mean temperature profiles are captured fairly well by the eddy dissipation(EDS),probability density function(PDF),and laminar flamelet combustion ***,the EDS-finite-rate combustion model fails to provide an acceptable temperature *** general,the flamelet model illustrates little superiority over the PDF model,and to some extent the PDF model shows better performance than the EDS model.

关键词：燃烧室燃烧模型扩散火焰热转移