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WATER WAVES IN AN ELASTIC VESSEL

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Acta Mechanica Sinica 1997年第4期13卷 289-303页

作者： d. y. Hsieh department of Mathematics Hong Kong University of Science and Technology Hong Kong

Linear and nonlinear analyses of water waves in an elastic vessel are carried out to study the dramatic phenomena of dragon Wash as well as related controllable experiments. It is proposed that the capillary edge waves are generated by parametric resonance, which is shown to be a possible mechanism for both rectangular an circular vessels. For circular vessel, the normal geometric resonance is also operating, thus greatly. enhance the dramatic effect. The mechanism of nonlinear mode-mode interaction is proposed far the generation of axisymmetric low-frequency gravity waves by the high-frequency external excitation. A simple model system is studied numerically to demonstrate explicitly this interaction mechanism.

关键词： water waves elastic vessel dragon Wash

Microstructural evolution and mechanical properties of Mg-9.8Gd-2.7y-0.4Zr alloy produced by repetitive upsetting

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Journal of Materials Science & Technology 2018年第7期34卷 1067-1075页

作者： H.Zhou H.y.Ning X.L.Ma d.d.yin L.R.Xiao X.C.Sha y.d.yu Q.d.Wang y.S.Li Nano and Heterogeneous Materials Center School of Materials and EngineeringNanjing University of Science and TechnologyNanjing210094China Institute of Microstructure and Property of Advanced Materials Beijing University of TechnologyBeijing 100124China School of Mechanical and Electrical Engineering Heilongjiang Institute of TechnologyHeilongjiang 150050China School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040China department of Materials Science&Engineering North Carolina State UniversityRaleighNC 27695USA Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduSichuan 610031China National Engineering Research Center of Light Alloys Net Forming and State Key Laboratory of Metal Matrix CompositeShanghai Jiao Tong University200240 ShanghaiChina

A newly developed severe plastic deformation （SPd） technique, i.e. repetitive upsetting （RU）, is employed to improve the strength and ductility of a Mg-Gd-y-Zr alloy. during the RU processing, dynamic recrystallization occurs in the Mg alloy, which leads to a significant grain refinement from 11.2 p.m to 2.8 μm. The yield strength （yS）, ultimate tensile strength （UTS） and elongation increase simultaneously with increasing RU passes. The microstructural evolution is affected by processing temperatures. dynamic recrystallization prevails at low temperatures, while dynamic recovery is the main effect factor at high temperatures. Texture characteristics gradually become random during multiple passes of RU processing, which reduces the tension-compression asymmetry of the Mg-Gd-y-Zr alloy. 2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Severe plastic deformation (SPd) Repetitive upsetting (RU) Mg-RE alloy Mechanical properties

Capsule endoscopy: Improving transit time and image view

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World Journal of Gastroenterology 2005年第37期11卷 5863-5866页

作者： Zvi Fireman d Paz y Kopelman department of Gastroenterology Hillel yaffe Hadera and Bruce Rappaport Faculty of Medicine Technion Haifa Israel

AIM： To evaluate the effect of various methods of small bowel preparation on the transit time and the quality of visualization of the entire small bowel mucosa. METHOdS： Ninety-five patients underwent capsule endoscopy （CE） by easily swallowing the capsule. They were divided into three study groups according to the preparation used： group A （n = 26） by polyethylene glycol （PEG） liter or with sodium phosphate （SP） 12 h prior to the CE study; group B （n = 29） by erythromycin 1 h prior to the CE study; and group C （n = 40） without any preparation. Visualization ranged from good to satisfactory to poor. RESULTS： The gastric emptying time in the group prepared with erythromycin was shorter but without statistical significance and the small bowel transit time was unaffected. In elderly subjects prepared by PEG or SP, the gastric emptying time was significantly longer （163.7 rain, P = 0.05）. The transit times of the three sub-groups were not affected by gender or pathology. The grade of cleaning of the entire study group was 3.27±1.1. The erythromycin group presented significantly the worst quality of images （P = 0.05） compared to the other sub-groups. Age, gender, and pathology had no effect on the quality of the cleaning of the small bowel in the sub-groups. One （1.05%） case had no natural excretion. CONCLUSION： Erythromycin markedly reduces gastric emptying time, but has a negative effect on the quality of the image in the small bowel. The preparation of elderly subjects with PEG or SP has a negative effect on the small bowel transit time.

关键词： Capsule endoscopy Gastric emptying time Small bowel transit time View Erythromycin Polyethylene glycol

INFLUENCE OF ALLOyING ELEMENTS ON HydROGEN dIFFUSION USING SCM-dV-X_α

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 71-76页

作者： y.Huang d.M.Xing School of Materials Science and Engineering Tianjin University Tianjin 300072 ChinaSchool of Physics Tianjin Normal UniversityTianjin 300071China

The influence of alloy composition (Ti, Mn, TiN) on hydrogen diffusion in Fe was studied in detail using SCM-dV-Xα method. The voltage barriers were obtained via calculation on Fe clusters containing the alloy elements such as Ti, Mn as well as the chemical compound TiN respectively. The results showed that Ti element produced deep trap in Fe, decreasing the diffusion coefficient of hydrogen elements, Mn element did not produce deep trap in Fe, decreasing the diffusion coefficient slightly and TiN in Fe produced very deep "trap" decreasing the diffusion coefficient obviously. The calculation results were in agreement with experiment results.

关键词： hydrogen diffusion SCM-dV-Xα method cluster

RELATIONSHIP BETWEEN INFRAREd RAdIATION ANd CRySTAL STRUCTURE IN Fe-Mn-Co-Cu-O SPINELS

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Acta Metallurgica Sinica(English Letters) 2008年第1期21卷 15-20页

作者： y. Zhang d.J. Wen School of Material Engineering Soochow University Suzhou 215021 China

Ni^3＋ and Cr^3＋ doped Fe-Mn-Co-Cu-O spinels have been prepared by solid phase sintering. The valence states and distribution of transition ions in the spinel crystals are inferred by the consideration of thermodynamic principle and crystalline field theory. The mierostructure and performance of those are studied by X-ray diffraction （XRd）, Fourier transform infrared （FT-IR）, and IRE-2 infrared radiant instrument. Ni3＋ and Cr3＋ occupy the vacancies or substitute the other ions in the spinel structures and form diverse spinel structures, which exhibit infrared integral emissivities of 0.93 in the whole band, and 0. 94 in the band within 14-25μm too. The content of Fe2O3 and MnO2 in the spinel crystals changes, maybe it induces infrared radiativity of spinels differently.

关键词： Crystal structure Mineral Infrared radiation property

Effect of Heat Treatment Time on dy–Cu Alloy diffusion Process in dy-Containing Commercial Nd–Fe–B Sintered Magnets

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Acta Metallurgica Sinica(English Letters) 2018年第5期31卷 496-502页

作者： H.y.Liu G.Wang y.Hong d.C.Zeng School of Materials Science and Engineering South China University of Technology

In this paper, the grain boundary diffusion process（GBdP） using a dy70Cu30（at.%） alloy as the diffusion source was performed in a commercial sintered Nd–Fe–B magnet, and the effect of heat treatment time on the microstructure and magnetic properties of the magnet was investigated in detail. For the processed magnets heat-treated at 860℃, as heat treatment time increased, the coercivity and the depth of（Nd,dy）2Fe14B core–shell structure increased first and then decreased. However, when the heat treatment time was more than 2 h, the diffusion path of dy from the dy-rich shell phase into the Nd2Fe14B grains was revealed, and a nearly homogeneous（Nd,dy）2Fe14B phase was formed, which brought on the decrease in both the depth of visible core–shell structure and the coercivity of Nd–Fe–B magnet.

关键词： Sintered Nd-Fe-B magnets Grain boundary diffusion Heat treatment time Coercivity Micromagnetic simulation

Effects of yttria Addition on Microstructure,Mechanical Properties,Wear Resistance and Corrosive Wear Resistance of TiNi Alloy

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Journal of Materials Science & Technology 2009年第5期25卷 645-648页

作者： Hojat Ahmadi d.y.Li Meisam Nouri Faculty of Biosystems Engineering University of TehranIran department of Chemical and Materials Engineering University of AlbertaEdmontonCanada department of Materials Engineering Tarbiat Modares UniversityTehranIran

TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. But studies show that oxygen active elements can improve properties of some alloys, markedly. yttrium is one of the oxygen active elements. In this paper, the effects of yttria addition on properties of TiNi have been studied via micro-indentation, hardness, wear and corrosive wear tests. It is demonstrated that by addition of yttria to 5%, TiNi alloy can own improved mechanical properties and resistance to wear and corrosive wear.

关键词： yttria TiNi Mechanical behavior Wear corrosive Wear

Polyethylene glycol fusion repair of severed rat sciatic nerves reestablishes axonal continuity and reorganizes sensory terminal fields in the spinal cord

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Neural Regeneration Research 2025年第7期20卷 2095-2107页

作者： Emily A.Hibbard Liwen Zhou Cathy Z.yang Karthik Venkudusamy yessenia Montoya Alexa Olivarez George d.Bittner dale R.Sengelaub Program in Neuroscience Indiana UniversityBloomingtonINUSA department of Neuroscience University of Texas at AustinAustinTXUSA

Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically *** used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic *** have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor ***,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target *** this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic *** adult male and female rats(Sprague–dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of *** action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury *** success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days *** 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish ***-fusion repair reestablished axonal *** to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal ***,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repa

关键词： axotomy dorsal horn peripheral nerve injury plasticity polyethylene glycol(PEG) sciatic nerve sensory terminals wheat germ agglutinin horseradish peroxidase

COORELATION ANALySIS OF SURFACE PRESSURE FLUCTUATIONS ON THREE EQUISPACEd CyLINdERS

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Journal of Hydrodynamics 2001年第2期13卷 55-62页

作者： dong, L.y. Xu, y.H. Huang, d.Q. Inst. of Appl. Math. and Mech. Shanghai Univ. Shanghai 200072 China

The fluctuating pressures on the surface of three circular cylinders in equispaced arrangement were measured simultaneously in the medium subcritical regime (Re=3×104). The distributions of their rms values and circumferential correlation were obtained in the spacing range from 1.25 to 6.0. The spatial correlation of pressures of two pressure taps on two different cylinders at the same azimuth was investigated as well. Owing to different flow patterns in various arrangements and spacing, these correlation curves of pressure show different distributions. The lift fluctuation can be estimated qualitatively from the circumferential coefficient curve with the knowledge of the rms pressure distribution. Some critical spacing for each arrangement were found that the flow regimes and the corresponding pressure correlation take a sudden change. Flow interference between cylinders in each arrangement was also discussed with various flow regimes.

关键词： Cylinders (shapes) Experiments Flow interactions Flow patterns Pressure distribution Pressure measurement