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Journal of Materials Science & Technology 2021年第14期73卷 91-100页

作者： P.L.Niu w.y.li D.L.Chen State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical UniversityXi'an710072.China Department of Mechanical and Industrial Engineering Ryerson University350 Victoria StreetTorontoOntarioM5B2K3Canada

Cyclic deformation behavior of friction-stir-welded dissimilar AA2024-T351 to AA7075-T65 aluminum alloy joints was evaluated via stepwise tests at different strain rates,along with transmission electron microscopy examinations to characterize the precipitates required to assess internal *** backscatter diffraction was employed to observe the inhomogeneous microstructures of the FSwed *** localization appeared in the heat affected zone(HAZ)of AA2024 *** cyclic deformation of 500 cycles at a total strain amplitude of 0.5%,the strength of the dissimilar joints resumed basically to that of AA2024 base *** the AA2024 HAZ was obviously hardened,which should be attributed to the introduced dislocations during cyclic deformation *** hardening capacity of the joints increased with decreasing strain rate.

关键词： Friction stir welding Dissimilar aluminum alloys Strain localization Cyclic hardening Slip irreversibility

Experimental and numerical investigations of bonding interface behavior in stationary shoulder friction stir lap welding

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Journal of Materials Science & Technology 2019年第1期35卷 192-200页

作者： Q.wen w.y.li w.B.wang F.F.wang y.J.Gao V.Patel State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical University China FSw Center China Academy of Launch Vehicle Technology Beijing Institute of Astronautical Systems Engineering Capital Aerospace Machinery Company Pandit Deendayal Petroleum University

Stationary shoulder friction stir lap welding(SSFSLw) was employed to weld 2024 aluminum alloy. A coupled Eulerian-Lagrangian(CEL) model was developed to investigate the lap interface behavior during SSFSLw. Numerical results of material movement and equivalent plastic strain were in good agreement with the experimental work. with increasing welding speed, the distances from the hook tip to the top surface of the upper workpiece on the retreating side(RS) and the advancing side(AS) increase, while the distance between two wave-shaped alclads decreases. A symmetric interface bending is observed on the AS and the RS during plunging, while the interface bending on the AS is bigger than that on the RS during welding. The peak temperature of the interface on the AS is higher than that on the RS. The equivalent plastic strain gradually increases as the distance to the weld center decreases, and its peak value is obtained near the bottom of the weld.

关键词： Stationary shoulder friction stir lap welding Coupled Eulerian-Lagrangian Temperature field Material distribution Equivalent plastic strain

On the double-side probeless friction stir spot welding of AA2198 Al-li alloy

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Journal of Materials Science & Technology 2019年第5期35卷 784-789页

作者： Q.Chu w.y.li H.L.Hou X.w.yang A.Vairis C.wang w.B.wang State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical University Xi'an 710072 China Beijing Aeronautical Manufacturing Technology Research Institute Beijing 100024 China Mechanical Engineering Department TEI of Crete HeraklionCrete71004 Greece

Double-side probeless friction stir spot welding (DP-FSSw) of AA2198 alloy was conducted to investigate the microstructure and mechanical properties. Compared with common single-side probeless friction stir spot welding (P-FSSw), the plastic strain during DP-FSSw is nearly symmetrical with respect to the bondline to suppress the extension of hook defect, which is detrimental to the joint mechanical strength. with DP-FSSw, a fully metallurgically bonded region has formed due to severe plastic deformation at high temperatures. Tensile/shear tests show that the joint strength could exceed 8 kN, which is comparable to P-FSSw and refill FSSw, and all fractures happen in a shear failure mode as cracks extend along the in terface of two sheets. The microhard ness profile exhibits a uniform distribution along the thick ness direction, in which the hook defect shows the lowest value.

关键词： Friction stir welding Double-side Al-li alloy Microstructure Mechanical property

Improving weld formability by a novel dual-rotation bobbin tool friction stir welding

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Journal of Materials Science & Technology 2018年第1期34卷 135-139页

作者： F.F.wang w.y.li J.Shen Q.wen J.F.dos Santos State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical University Helmholtz-Zentrum Geesthacht Institute of Materials Research Materials Mechanics China Academy of Launch Vehicle Technology Beijing Institute of Astronautical Systems Engineering

A novel dual-rotation bobbin tool friction stir welding （DBT-FSw） was developed, in which the upper shoulder （US） and lower shoulder （LS） have different rotational speeds. This process was tried to weld 3.2 mm thick alunlinum-lithium alloy sheets. The metallographic analysis and torque measurement were carried out to characterize the weld formabiliw. Experimental results show that compared to conven- tional bobbin tool friction stir welding, the DBT-FSw has an excellent process stability, and can produce the defect-free joints in a wider range of welding parameters. These can be attributed to the significant improvement of material flow caused by the formation of a staggered layer structure and the unbalanced force between the US and LS during the DBT-FSw process.

关键词： Bobbin tool friction stir welding Dual rotation Material flow Microstructure Microhardness

Remifentanil induces higher incidence and more severity of cough than equivalent dose of fentanyl or sufentanil

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Remifentanil induces higher incidence and more severity of c...

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

2008年第七次华东六省一市麻醉学学术会议暨浙江省麻醉学术年会

作者： J.C.Shen,~1 J.G.Xu,~2 Z.Q.Zhou,~3 H.J.liu,~4 w.y.li,~3 and J.J.yang~3 1 Visiting Staff,2 Professor,3 Associated Professor and 4 Resident,Department of Anesthesiology,Jinling Hospital,Second Military Medicine University,Nanjing 210002,China

Summary:A prospective,randomized,double-blind study was designed to compare the incidence and severity of cough induced by administrating equivalent dose of fentanyl 2 ***,sufentanil 0.2 *** remifentanil 2 *** 5 s in 315 *** incidence and severity of cough were observed within 2min after drug *** group experienced a higher incidence of

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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 Key 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 Key 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

Constraints on holographic QCD phase transitions from PTA observations

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 71-78页

作者： Song He li li Sai wang Shao-Jiang wang Center for Theoretical Physics and College of Physics Jilin University School of Physical Science and Technology Ningbo University Max Planck Institute for Gravitational Physics (Albert Einstein Institute) CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences (UCAS) School of Physical Sciences University of Chinese Academy of Sciences (UCAS) Theoretical Physics Division Institute of High Energy Physics Chinese Academy of Sciences

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves(Gws) within the standard model of particle physics. If these background Gws could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

Cell polarization in ischemic stroke: molecular mechanisms and advances

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Neural Regeneration Research 2025年第3期20卷 632-645页

作者： yuanwei li Xiaoxiao Xu Xuan wu Jiarui li Shiling Chen Danyang Chen Gaigai li Zhouping Tang Department of Neurology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei ProvinceChina

Ischemic stroke is a cerebrovascular disease associated with high mortality and disability rates. Since the inflammation and immune response play a central role in driving ischemic damage, it becomes essential to modulate excessive inflammatory reactions to promote cell survival and facilitate tissue repair around the injury site. Various cell types are involved in the inflammatory response, including microglia, astrocytes, and neutrophils, each exhibiting distinct phenotypic profiles upon stimulation. They display either proinflammatory or anti-inflammatory states, a phenomenon known as ‘cell polarization.’ There are two cell polarization therapy strategies. The first involves inducing cells into a neuroprotective phenotype in vitro, then reintroducing them autologously. The second approach utilizes small molecular substances to directly affect cells in vivo. In this review, we elucidate the polarization dynamics of the three reactive cell populations(microglia, astrocytes, and neutrophils) in the context of ischemic stroke, and provide a comprehensive summary of the molecular mechanisms involved in their phenotypic switching. By unraveling the complexity of cell polarization, we hope to offer insights for future research on neuroinflammation and novel therapeutic strategies for ischemic stroke.

关键词： astrocyte polarization immune regulation inflammation ischemic injury microglia polarization neutrophil polarization signaling pathways stroke

Insight Into the Separation-of-Variable Methods for the Closed-Form Solutions of Free Vibration of Rectangular Thin Plates

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 329-355页

作者： yufeng Xing ye yuan Gen li Institute of Solid Mechanics Beihang University(BUAA)Beijing100191China

The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytical solutions for free vibration and eigenbuckling of rectangular plates and circular cylindrical *** taking the free vibration of rectangular thin plates as an example,this work presents the theoretical framework of the SOV methods in an instructive way,and the bisection–based solution procedures for a group of nonlinear eigenvalue ***,the explicit equations of nodal lines of the SOV methods are presented,and the relations of nodal line patterns and frequency orders are *** is concluded that the highly accurate SOV methods have the same accuracy for all frequencies,the mode shapes about repeated frequencies can also be precisely captured,and the SOV methods do not have the problem of missing roots as well.

关键词： Separation-of-variable method Rayleigh quotient nodal line eigenvalue equation bisection method

Local magnetic moment oscillation around an Anderson impurity on graphene

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 192-201页

作者： Shuai li Zhen Ma Jin-Hua Gao School of Science Hebei University of Science and Technology School of Electronics and Information Zhengzhou University of Light Industry School of Physics and wuhan National High Magnetic Field Center Huazhong University of Science and Technology

we theoretically investigate the spin resolved Friedel oscillation （FO） and quasiparticle interference （QPI） in graphene induced by an Anderson *** the impurity becomes magnetic,the resulted FO becomes spin dependent,which gives rise to a local magnetic moment oscillation with an envelop decaying as r-2in real space in the doping ***,at half filling,the electron density and local magnetic moment will not oscillate but decay as *** spin resolved FO has both sublattice and spin ***,the local magnetic moment decay at half filling only occurs at one sublattice of graphene,which is quite like the phenomenon observed in the STM experiment (***ález-Herrero et al.,Science 352,437 （2016）).we further give an analytic formula about such spin dependent FO based on the stationary phase ***,we study the interference of quasiparticles around the magnetic impurity by calculating the spin dependent Fourier-transformed local density of states （FT-LDOS）.Our work gives a comprehensive understanding about the local magnetic moment oscillation around an Anderson impurity on graphene.

关键词： Friedel oscillation local magnetic moment graphene Anderson impurity