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Frequency Veering of Rotating Metal Porous Twisted Plate with Cantilever Boundary Using shell Theory

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Acta Mechanica solida sinica 2022年第2期35卷 282-302页

作者： y.y.Liu y.X.Hao W.Zhang L.T.Liu s.W.yang y.T.Cao College of Mechanical Engineering Beijing Information Science and Technology UniversityBeijing 100192China College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China

The frequency veering of a metal porous rotating cantilever twisted plate with twist angle and stagger angle is *** porous materials may have the characteristics of gradient or uniform distribution along the thickness *** on the classical shell theory,considering the influence of centrifugal force produced by high-speed rotation,the free vibration equations of a rotating cantilever twisted plate are *** the polynomial function and Rayleigh-Ritz method,the natural frequencies and mode shapes of the metal porous cantilever twisted plate in both static and rotating states are *** accuracy of the present theory and calculation results is confirmed by a comparison between them and the results available from the literature and those obtained from *** influences of the thickness ratio,porosity,twist angle,stagger angle and rotational velocity on the frequency veering and mode shape shift of the rotating cantilever twisted plate with porous material under three different distributions are *** should be mentioned that the frequency veering accompanied by mode shape shift occurs in both static and dynamic states.

关键词： Frequency veering Rotating twisted plate Cantilever boundary Metal porous

RECRysTALLIZATION BEHAVIOR AND PRIOR AUsTENITE GRAIN BOUNDARy CORROsION IN THE PLANE sTRAIN COMPREssION CONDITION FOR A LOW CARBON X70 PIPELINE sTEEL

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Acta Metallurgica sinica(English Letters) 2004年第6期17卷 830-834页

作者： y.H.Li J.Wang y.s.Li y.Kshan Dep.ofMaterialscienceandEngineering ShenyangLigongUmversityShenyang110168China InstituteofIndustry NingboPolytechnicNingbo315800China schoolofMaterial＆ChemicalEngineering SouthernInstituteofMetallurgy＇Ganzhou341000China InstituteofMetalResearch TheChineseAcademyofSdencesShenyang110016China

Recrystallization behavior of a low carbon X70 pipeline steel was studied in the plane strain compression condition. It was found that the dynamic recovery but no dynamic recrystal- lization occurred in the current ex... 详细信息

关键词： pipeline steel, plane strain compression, recrystallization, austenite grain boundary

Deciphering deformation mechanisms of hierarchical dual-phase CrCoNi coatings

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Journal of Materials science & Technology 2020年第4期39卷 7-13页

作者： s.J.Tsianikas y.Chen Z.Xie school of Mechanical Engineering The University of AdelaideAdelaideSA5005Australia Centre for Advanced Thin Film Materials and Device Faculty of Materials and EnergySouthwest UniversityChongqing400715China school of Engineering Edith Cowan UniversityWA6027Australia

Hierarchical Cr Co Ni medium entropy alloy(MEA)thin films with a dual-phase face-centred cubic(FCC)and hexagonal closed-packed(HCP)nanostructure were prepared on M2 steel substrates by closed field unbalanced magnetron *** tests show an ultra-high hardness of 9.5 GPa,attributable to large amounts of innate planar defects(i.e.,growth twins and stacking faults)impeding dislocation motion in the coatings.A deep analysis of undeformed and post-mortem samples reveals grain refinement as the dominant deformation mechanism in FCC dominated regions,while phase transformation and shear banding played major roles in regions occupied by HCP *** grain refinement was facilitated by twin/matrix lamellae,with dislocations piling up and arranging into interconnecting grain *** shear banding was accelerated by innate planar defects in the HCP phase due to a lack of slip *** particular interest is the observation of HCP→FCC phase transformation,which was catalysed by deformation-induced grain reorientation with innate stacking faults acting as embryos to grow the FCC *** results of this work suggest that multiple deformation pathways could be activated in Cr Co Ni coatings with assistance of growth defects,thereby imparting these technically important coatings appreciable ductility.

关键词： Medium entropy alloys sputter deposition Grain refinement shear banding Phase transformation

Autoantibody profiles in autoimmune hepatitis and chronic hepatitis C identifies similarities in patients with severe disease

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World Journal of Gastroenterology 2017年第8期23卷 1345-1352页

作者： kawa Amin Aram H Rasool Ali Hattem Taha AM Al-Karboly Taher E Taher Jonas Bystrom Department of Medical science Respiratory Medicine and AllergologyClinical Chemistry and Asthma Research CentreUppsala University and University Hospital Department of Microbiology/Immunology School of MedicineUniversity of Sulaimani Laboratory Department General Hospital of Derbandixan Department of Community Health Sulaimani Polytechnic University Department of Medicine School of MedicineFaculty of Medical SciencesUniversity of Sulaimani Experimental Medicine and Rheumatology William Harvey Research InstituteBarts and the LondonQueen MaryUniversity of London

To determine how the auto-antibodies (Abs) profiles overlap in chronic hepatitis C infection (CHC) and autoimmune hepatitis (AIH) and correlate to liver *** of antinuclear Ab, smooth muscle antibody (sMA) and liver/kidney microsomal-1 (LKM-1) Ab and markers of liver damage were determined in the sera of 50 patients with CHC infection, 20 AIH patients and 20 healthy controls using enzyme linked immunosorbent assay and other immune *** found that AIH patients had more severe liver disease as determined by elevation of total IgG, alkaline phosphatase, total serum bilirubin and serum transaminases and significantly higher prevalence of the three non-organ-specific autoantibodies (auto-Abs) than CHC patients. Antinuclear Ab, sMA and LKM-1 Ab were also present in 36% of CHC patients and related to disease severity. CHC cases positive for auto-Abs were directly comparable to AIH in respect of most markers of liver damage and total IgG. These cases had longer disease duration compared with auto-Ab negative cases, but there was no difference in gender, age or viral load. KLM-1sup>+sup> Ab CHC cases showed best overlap with ***-Ab levels in CHC may be important markers of disease severity and positive cases have a disease similar to AIH. Auto-Abs might have a pathogenic role as indicated by elevated markers of liver damage. Future studies will unravel any novel associations between these two diseases, whether genetic or other.

关键词： Autoantibody Inflammatory diseases Immune system Hepatitis C virus smooth muscle antibody Liver/kidney microsomal-1 autoantibody Anti-nuclear antibody

Experimental and finite element analysis for fracture of coating layer of galvannealed steel sheet

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Transactions of Nonferrous Metals society of China 2011年第A01期21卷 111-116页

作者： s.I.KIM J.U.HER y.C.JANG y.LEE sheet Products and Process Research Group POSCO Techology Research Laboratory Department of Mechanical Engineering Chung-Ang University

Mechanical properties of galvannealed (GA) steel sheet used for automotive exposed panel and predicted failure phenomenon of its coating layer were evaluated using finite element method. V-bending test was performed to understand better the fracture of coating layer of GA steel sheet during plastic deformation. yield strength of the coating layer was calculated by using a relative difference between hardness of coating layer measured from the nano-indentation test and that of substrate. To measure shearing strength at the interface between substrate and coating layer, shearing test with two specimens attached by an adhesive was carried out. Using the mechanical properties measured, a series of finite element analyses coupled with a failure model was performed. Results reveal that the fracture of coating layer occurs in an irregular manner at the region where compressive deformation is dominant. Meanwhile, a series of vertical cracks perpendicular to material surface are observed at the tensile stressed-region. It is found that 0.26-0.28 of local equivalent plastic strain exists at the coating and substrate at the beginning of failure. The fracture of coating layer depends on ductility of the coating layer considerably as well.

关键词： galvannealed steel sheet fracture simulation coating layer finite element analysis, failure model

FEM sIMULATION FOR LAsER FORMING PROCEssING

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Acta Metallurgica sinica(English Letters) 2004年第3期17卷 317-322页

作者： L.Q.Li y.B.Chen X.y Wang s.y Lin state Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Harbin Research Institute of Welding Harbin 150001 ChinaState Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Harbin Research Institute of Welding Harbin 150001 ChinaHarbin Research Institute of Welding Harbin 150001 ChinaHarbin Research Institute of Welding Harbin 150001 China

Laser forming involves heating sheet metal workpiece along a certain path with adefocused laser beam directed irradiate to the surface. During laser forming, a tran-sient temperature fields is caused by the irradiation and travelling of a laser beam.Consequently, thermal expansion and contraction take place, and allows the thermal-mechanical forming of complex shapes. This is a new manufacturing technique thatforming metal sheet only by thermal stress. Therefore, the analysis of temperaturefields and stress fields are very useful for studying the forming mechanism and con-trolling the accuracy of laser forming. The non--liner finite element solver, MARC, isemployed to solve the thermal--mechanical analysis. Using this model, the stress andstrain distribution of pure aluminum plate with different thickness are analyzed. Theinfluence of scanning speed on temperature fields and plastic strain of metal sheet un-der the condition of constant line energy are also presented. Numerical results agreewell with the experimental results.

关键词： laser forming FEM simulation temperature fields stress distributton

Emissions of Er3+ and yb3+ co-doped srZrO3 nanocrystals under near-infrared and near-ultraviolet excitations

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Journal of Advanced Ceramics 2020年第4期9卷 413-423页

作者： Hyeontae Lim Juyeong Lim soyoung Jang y.s.Lee Department of Physics Soongsil UniversitySeoul06978Republic of Korea

In this study,the upconversion(UC)emissions of Er3+and yb3+co-doped srZrO3 nanocrystals(NCs)were investigated in terms of the thermal annealing temperature and concentration of Er3+ions and compared with the emissions under a near-ultraviolet(near-UV)*** NCs were synthesized by the combustion method,and the as-synthesized NCs were post-annealed at high *** X-ray diffraction patterns revealed that the grain sizes and crystallinity degrees of the samples increased with increasing annealing *** photoluminescence spectra of our samples exhibited strong green and very weak red emissions with the near-UV excitation,originating from the f-f transitions in the Er3+***,under near-infrared(near-IR)excitation,we identified sizable visible emissions at 525,547,and 660 nm in our NCs,which indicated that the UC process successfully occurred in our *** UC emissions were maximized in the NCs with an Er3+concentration of 0.02 and thermal annealing at 1000°*** found that the intensity ratios of red to green emissions increased with increasing annealing *** discussed the differences in the emissions between near-UV and near-IR excitations.

关键词： Er3+and yb3+co-doped srZrO3 upconversion downshifting nanocrystals combustion method annealing temperature

Physical mechanism for origin of streamwise vortices in mode A of a square-section cylinder

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Acta Mechanica sinica 2019年第2期35卷 411-418页

作者： L. M. Lin s. y. shi y. X. Wu Key Laboratory for Mechanics in Fluid solid Coupling systems Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China school of Engineering sciences University of Chinese Academy of Sciences Beijing 100049 China

In the present paper, physical mechanism responsible for origin of streamwise vortices in mode A appeared in the threedimensional (3-D) wake transition of a square-section cylinder is investigated. Direct numerical simulations at a Reynolds number of 180 firstly show that such streamwise vorticity is not originated from lateral surfaces. Then through the analysis of local flow field in the immediate neighborhood of rear surface, based on the theory of vortex-induced vortex, a new physical mechanism is identified. At first, the vertical vorticity on rear surface is generated by the intrinsic three-dimensional instability with the same instability wavelength of mode A. Then the streamwise vorticity at a specific sign is induced by such vertical vorticity, convected and concentrated in the shear layers. Finally, streamwise vortices are formed and shed with alternatively shedding spanwise vortices in the near wake. Moreover, the effect of induced spanwise vorticity on original two-dimensional (2-D) spanwise vorticity is also presented in detail.

关键词： Mode A streamwise vortices Wake square cylinder Vortex-induced vortex

Nonlinear excitations and“peakons”of a(2+1)-dimensional generalized Broer-Kaup system

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Acta Mechanica sinica 2007年第2期23卷 209-214页

作者： X. y. Tang K. W. Chow s. y. Lou Department of Physics Shanghai Jiao Tong UniversityShanghai 200030 China Department of Mechanical Engineering University of Hong KongHong Kong China Department of Physics Ningbo UniversityNingbo 315211 China

shallow water waves and a host of long wave phenomena are commonly investigated by various models of nonlinear evolution equations. Examples include the Korteweg-de Vries, the Camassa-Holm, and the Whitham-Broer-Kaup （WBK） equations. Here a generalized WBK system is studied via the multi-linear variable separation approach. A special class of wave profiles with discontinuous derivatives （＂peakons＂） is developed. Peakons of various features, e.g. periodic, pulsating or fractal, are investigated and interactions of such entities are studied.

关键词： shallow water wave .Excitation Broer-Kaup system .Peakon