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A hyperbolic Lindstedt-Poincare method for homoclinic motion of a kind of strongly nonlinear autonomous oscillators

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Acta Mechanica Sinica 2009年第5期25卷 721-729页

作者： y.y.chen S.H.chen K.y.Sze Department of Applied Mechanics and Engineering Sun yat-sen University Department of Mechanical Engineering The University of Hong Kong Department of Applied Mechanics and Engineering Sun Yat-sen University

A hyperbolic Lindstedt-Poincare method is presented to determine the homoclinic solutions of a kind of nonlinear oscillators, in which critical value of the homoclinic bifurcation parameter can be determined. The generalized Lienard oscillator is studied in detail, and the present method＇s predictions are compared with those of Runge-Kutta method to illustrate its accuracy.

关键词： Lindstedt-Poincare method Hyperbolic function Nonlinear autonomous oscillator - Homoclinic orbit

NUMERICAL SIMULATION OF INDUCTION SKULL MELTING PROCESS FOR TITANIUM-ALUMINIUM BASE ALLOy

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 928-933页

作者： Z.y.chen L.J.Xu F.T.Kong Q.Shu y.y.chen SchoolofMaterialsScienceandEngineering HarbinInstituteofTechnologyHarbin150001China

The mathematics model for temperature field of water-cooling copper crucible induction skull melting process was established. The program for simulating temperature field of melting process was developed with finite element method. The temperature field of the melting process for Ti-47Al-2Cr-2Nb alloy was calculated. During melting period, the temperature is raised gradually along radius augmentation direction. The elements of the charge near the crucible wall are molten first. The center elements of the charge are molten last. The melting time of the center element is just that of all the charge melting. The melting time of Ti-47Al-2Cr-2Nb alloy is 15min. In which, the charge was heated by low power 80kW for 9min and by high power 300kW for 6min. When melting Ti-47Al-2Cr-2Nb alloy, the loading power is nearly direct proportion to melt temperature. Increasing loading power may raise melt temperature. The best melting power of Ti-47Al-2Cr-2Nb alloy is 305-310kW. This is identical with the melting test and has guidance sense to the melting process of actual titanium alloy.

关键词： TiAl base alloy melting numerical simulation

Rational design of AgGaS/ZnS/ZnS quantum dots with a near-unity photoluminescence quantum yield via double shelling scheme

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Journal of Materials Science & Technology 2024年第2期169卷 235-242页

作者： H.X.Lu H.Liu Z.Z.Fu y.y.chen H.Q.Dai Z.Hu W.L.Zhang R.Q.Guo Institute for Electric Light Sources School of Information Science and TechnologyFudan UniversityShanghai 200433China Institute of Future Lighting Academy for Engineering and TechnologyFudan UniversityShanghai 200433China yiwu Research Institute of Fudan University YiwuZhejiang 322000China Zhongshan-Fudan Joint Innovation Center Zhongshan 528437China

In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(QDs).In the first step,an inner ZnS shell was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer ZnS shell,thereby facilitating the formation of a thick outer *** the two-step shelling process,the synthesized AgGaS/ZnS/ZnS QDs showed an excellent photoluminescence quantum yield(PLQy)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PLQy reported thus far for AgGaS ***,the effect of halogen ions in Zn precursors on the shelling process was *** was proposed that the capacity of halogen ions to coordinate with the QDs influenced the balance between Zn cation diffusion and ZnS shelling ***,the ZnS shelling reaction was dominant when ZnCl_(2)was employed,while Zn cation diffusion was the dominant process under the I^(−)-rich *** work provides insights into the interfacial restructuring during the ZnS shelling and offers a clear map for the tailored synthesis of core/shell QDs.

关键词： AgGaS Quantum dots Photoluminescence Core/shell Alloyed core/shell interface

Effect of 2–6 at.% Mo addition on microstructural evolution of Ti-44Al alloy

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Journal of Materials Science & Technology 2018年第7期34卷 1196-1204页

作者： S.Z.Zhang Z.W.Song J.C.Han C.J.Zhang P.Lin D.D.Zhu F.T.Kong y.y.chen School of Materials Science and Engineering Taiyuan University of Technology Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology School of Mechanical Engineering Taiyuan University of Technology School of Mechanical Engineering Quzhou University State Key Laboratory for Advanced Welding and Jointing Harbin Institute of Technology

In order to understand the effect of Mo alloying on the microstructural evolution of TiAl alloy, the as-cast microstructure, heat treated microstructure characteristic, and hot compression microstructure evolution of Ti-44Al alloy have been studied in this work. The as-cast microstructure morphology changes from （γ＋α2） lamellar colony and β/β0＋γ mixture structure to β/β0 phase matrix widmannstatten structure, when Mo content increases from 2 at.% to 6 at.%. Affected by the relationship between β phase and α90℃phase, the angles between the lamellar orientation and the block β/β0 phase are roughly at 0℃, 45℃ and 90℃. Comparing with heat treatment microstructure, the hot compression microstructure contains less β/β0 phase, however, theβ/β0 phase containing 2Mo alloy and 3Mo alloy hot compressed at 1275 ℃ has the inverse tendency. In addition, （α2 ＋γ） colony is decomposed by the discontinuous transformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Phase transformation Titanium aluminides Heat treatment Microstructure evolution,β/βo phase

NEEDLING REVISION WITH PRE-OPERA- TIVE INJECTION OF MITOMyCIN-C FOR FAILED FILTERING BLEBS

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国际眼科杂志 2003年第1期3卷 75-75页

作者： y.y.chen Kaohsiung Veterans General Hospital and National yang-Ming Uni-versity School of Medicine Taiwan

Purpose: To evaluate the effect of needling revision with pre-op-erative subconjunctival injection of mitomycin-C for the failed filtering blebs. Methods: Retrospective chart review of 25 eyes in 22 patients with fail... 详细信息

关键词：滤过术手术败水泡细针修整术前丝裂霉素 C注射

STRESS WAVE PROPAGATION IN COMPOSITE WITH DIFFERENT FIBER END GEOMETRIES (Abstract)

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昆明理工大学学报(自然科学版) 1988年第6期 78-78页

作者： H. Pih Q. Bi y.y.chen P.ye Department of Engineering Science and Mechanics The University of Tennessee

The effect of fiber end geometries on the propagating stress wave in composite models was investigated by the dynamic photoelastic method. Aluminum fibers with rectangular, semicircular,V—and wedge-shape ends were cast in epoxy resin to form the models. Impact was applied by the bullet of a rifle. Effects of the fiber on the dynamic birefringent patterns were analyzed by comparing the fringe patterns with a plain model of identical contour under the same loading conditions.

关键词： Composite material dynamic photoelastic

DyNAMIC STRESS-CONCENTRATION EFFECT ON STRESS WAVES IN COMPOSITE MODELS WITH DIFFERENT FIBER-END GEOMETRIES (Abstract)

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昆明理工大学学报(自然科学版) 1988年第6期 78-78页

作者： H. Pih Q.Bi y.y.chen P.ye Department of Engineering Science and Mechanics The University of Tennessee

The stress-concentration effect of fiber-end geometries on the propagating stress waves in composite models was investigated by the dynamic photoelastic method. Aluminum fibers with rectangular, semicircular, V-and wedge-shape ends simulating such materials as reinforced concrete and fiber-bundle-reinforced composites were cast in epoxy resin to form the models. Impact was applide by the bullet of a rifle. The effects of the reinforced rod or fiber-bundle ends on the dynamic birefringent patterns were analyzed by comparing the fringe patterns at the same locations in a plain model of identical Contour under the same loading conditions.

关键词： composite moterial concentration

Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： Victor V.Chizhikov Igor y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).

关键词： epithelium Figure center

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 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