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Ductile Phase Toughened Brittle Materials

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Journal of Materials Science & Technology 1996年第2期12卷 124-134页

作者： Sun, XD Yeomans, ja UNIV SURREY DEPT MAT SCI & ENGNGUILDFORD GU2 5XHSURREYENGLAND

Toughening of brittle materials by the inclusion of ductile phases is governed by several important factors which include ceramic-ductile phase interfacial bond strength, physical and chemical compatibility between ceramic and ductile phase, geometry and mechanical properties of ductile phase. The present understanding of the effect of these factors on toughening is reviewed and clarified. Continuous ductile phases (network, fibre or plate) are found to be more efficient for the toughening of brittle materials than discrete ductile particles. However, ductile particle toughened brittle materials have the advantages of material homogeneity, isotropy, and particularly better high temperature properties. It has been demonstrated that the influence of interfacial bond strength is determined by the geometry of the ductile phase in the composites. For the comparatively continuous ductile phase, such as ductile network, fibre or plate, comparatively weak interfacial bond strength can promote partial debonding of the brittle matrix-ductile phase interface during crack propagation and is beneficial for toughening. For discrete particulate ductile phase toughened brittle materials, the small gauge length of the ductile phase often results in the ductile phase pull-out during crack propagation which is the main limitation to toughening. Thus strong bond strength is required to ensure the bridging of the crack by the ductile phase. The coefficient of thermal expansion (CTE) mismatch between matrix and ductile phase has also been correlated with the geometry of the ductile phase. In most of the ceramic/metal systems, the CTE of the ductile metal phase is greater than that of the ceramic matrix. In the case of ductile network, fibre or plate, the residual stress created by the CTE mismatch can contribute to toughening through its influence on the initial crack opening stress while the bridging of the crack by the ductile phase is still ensured. However, for discrete ductile parti

关键词： Brittleness

ON TRANSMISSION PROBLEM FOR KIRCHHOFF TYPE WAVE EQUATION WITH A LOCALIZED NONLINEAR DISSIPATION IN BOUNDED DOMAIN

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Acta Mathematica Scientia 2012年第3期32卷 893-906页

作者： Jeong ja Bae Department of Mathematics Dongeui UniversityPusan 614-714Korea

In this article, we consider the global existence and decay rates of solutions for the transmission problem of Kirchhoff type wave equations consisting of two physi- cally different types of materials, one component is a Kirchhoff type wave equation with nonlinear time dependent localized dissipation which is effective only on a neighborhood of certain part of the boundary, while the other is a Kirchhoff type wave equation with nonlinear memory.

关键词： Existence of solution uniform decay transmission problem Kirchhoff type wave equation boundary value problem localized dissipation

Non-invasive investigation of inflammatory bowel disease

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World Journal of Gastroenterology 2001年第4期7卷 460-465页

作者： ja Tibble IBjarnason Department of Medicine GuysKings.St Thomass Medical SchoolBessemer RoadLondon SE5 9

The assessment of inflammatory activity in intestinal disease in man can be done using a variety of different techniques. These range from the use of non-invasive acute phase inflammatory markers measured in plasma such as C reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) (both of which give an indirect assessment of disease activity) to the direct assessment of disease activity by intestinal biopsy performed during endoscopy in association with endoscopic scoring systems. Both radiology and endoscopy are conventional for the diagnosis of inflammatory bowel disease (IBD). However these techniques have severe limitations when it comes to assessing functional components of the disease such as activity and prognosis. Here we briefly review the value of two emerging intestinal function tests. Intestinal permeability, although ideally suited for diagnostic screening for small bowel Crohn's disease, appears to give reliable predictive data for imminent relapse of small bowel Crohn's disease and it can be used to assess responses to treatment. More significantly it is now clear that single stool assay of neutrophil specific proteins (calprotectin, lactoferrin) give the same quantitative data on intestinal inflammation as the 4 day faecal excretion of 111Indium labelled white cells. Faecal calprotectin is shown to be increased in over 95% of patients with IBD and correlates with clinical disease activity. It reliably differentiates between patients with IBD and irritable bowel syndrome. More importantly, at a given faecal calprotectin concentration in patients with quiescent IBD, the test has a specificity and sensitivity in excess of 85% in predicting clinical relapse of disease. This suggests that relapse of IBD is closely related to the degree of intestinal inflammation and suggests that targeted treatment at an asymptomatic stage of the disease may be indicated.

关键词： Biological Markers Feces Humans Inflammatory Bowel Diseases Intestinal Mucosa

On Uniform Decay for Transmission Problem of Kirchhoff Type Viscoelastic Wave Equation

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Acta Mathematica Sinica,English Series 2010年第7期26卷 1197-1206页

作者： Jeong ja BAE Department of Mathematics Dongeui University

In this paper we consider the large time behavior of solutions to an n-dimensional transmission problem for two Kirchhoff type viscoelastic wave equations, that is, the wave propagation over bodies consisting of two physically different types of materials. One component is a simple elastic part while the other is a viscoelastic component endowed with a long range memory. We show that the dissipation produced by the viscoelastic part is strong enough to produce exponential or polynomial decay of the solution

关键词： existence of solution uniform decay wave equation boundary value problem a priori estimates

GLOBAL EXISTENCE FOR THE NONHOMOGENEOUS QUASILINEAR WAVE EQUATION WITH A LOCALIZED WEAKLY NONLINEAR DISSIPATION IN EXTERIOR DOMAINS

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Acta Mathematica Scientia 2009年第5期29卷 1203-1215页

作者： Jeong ja Bae Department of Mathematics University of Ulsan

It is proved that the global existence for the nonhomogeneous quasilinear wave equation with a localized weakly nonlinear dissipation in exterior domains.

关键词： quasilinear wave equation localized weakly nonlinear dissipation exterior domains

Nuclear Planetology:Especially Concerning the Moon and Mars

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Research in Astronomy and Astrophysics 2012年第10期12卷 1313-1380页

作者： Kyeong ja Kim Nobuyuki Hasebe Korea Institute of Geoscience and Mineral Resources Daejeon305-350 Korea Research Institute for Science and Engineering Waseda UniversityShinjukuTokyo 169-8555 Japan

To approach basic scientific questions on the origin and evolution of plan- etary bodies such as planets, their satellites and asteroids, one needs data on their chemical composition. The measurements of gamma-rays, X-rays and neutrons emit- ted from their surface materials provide information on abundances of major elements and naturally radioactive gamma-ray emitters. Neutron spectroscopy can provide sen- sitive maps of hydrogen- and carbon-containing compounds, even if buried, and can uniquely identify layers of carbon-dioxide frost. Nuclear spectroscopy, as a means of compositional analysis, has been applied via orbital and lander spacecraft to extrater- restrial planetary bodies： the Moon, Venus, Mars, Mercury and asteroids. The knowl- edge of their chemical abundances, especially concerning the Moon and Mars, has greatly increased in recent years. This paper describes the principle of nuclear spec- troscopy, nuclear planetary instruments carried on planetary missions so far, and the nature of observational results and findings of the Moon and Mars, recently obtained by nuclear spectroscopy.

关键词： nuclear planetology: planetary remote sensing -- elemental mapping --nuclear science payloads -- chemical abundance

Sensitivity to Combustible Gas for ZnO Thin Films

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Journal of Materials Science & Technology 1997年第4期13卷 302-305页

作者： Tan, GL Wu, ja Wu, XJ Dept. of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

A fine polycrystalline ZnO thin film with 0.3 similar to 0.6 mu m grain size was obtained by sol-gel process and a consequential heat treatment at 500 degrees C. The process of preparing ZnO thin film was analysed. The sensitivity and conductivity of ZnO thin films as combustible gas (CO, CH4, H-2) sensor as well as the influence of catalyst and pH value of the precursor on its sensitivity were studied in detail. The structure characteristics of ZnO thin film by different process were investigated by X-ray diffraction, thermal analysis and photoelectron spectrometer. The atomic ratio of Zn to O on the surface of ZnO thin film was found to be 1.14:1 measured from XPS result. The conductivity of the thin film increases greatly when doped with Al3+ ion but decreases while doped with Na+ ion.

关键词： Zinc oxide

Multirange Fractal Analysis on the Negative Correlation between Fractal Dimension of Fractured Surface and Toughness of Materials

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Journal of Materials Science & Technology 1996年第4期12卷 318-320页

作者： Lung, CW Jiang, ja Zhang, CH International Centre for Materials Physics Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

Applying the concept of multirange fractals, a new explanation to the Williford's multifractal curve on the relationship of fractal dimension with fracture properties in materials has been given. It shows the importance of factorizing out the effect of fractal structure from other physical causes and separating the appropriate range of scale from multirange fractals.

关键词： Fracture

Iksan526 Rice Callus Extract Induces Dedifferentiation of Rabbit Articular Chondrocytes via ERK1/2 and PI-3K/Akt Pathways

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Rice science 2020年第6期27卷 504-514页

作者： Seong-Hui EO Song ja Kim Department of Biological Sciences College of Natural SciencesKongju National UniversityGongju 32588Republic of Korea

The resveratrol-enriched transgenic rice line Iksan526(IS526),first developed by the Rural Development Administration of Korea using genetic engineering techniques,shows beneficial health effects in mitigating metabolic syndrome and ***,the effects of IS526 on the differentiation of chondrocytes and the underlying mechanism have not been investigated in *** this study,the effects and cellular regulatory mechanisms of IS526 on rabbit articular chondrocytes were *** IS526 callus extract treatment,the expression levels of differentiation-related proteins were detected via western blotting,Alcian blue staining and immune-luorescence ***526 decreased the type Ⅱ collagen and proteoglycan levels in dose-and time-dependent *** further analyzed the effects of IS526 on skeleton genesis in zebrafish larvae using Alcian blue staining,which showed a reduction in cartilage formation along with increased production of matrix metalloproteinase(MMP)-***526 also increased the phosphorylation of ERK1/2 and p38 kinase but inhibited the phosphorylation of *** inhibition of MMP-13 blocked the IS526-induced decrease in type Ⅱ collagen *** of p38 kinase or PI-3K/Akt with SB203580 and LY294002 enhanced the suppression of type Ⅱ collagen,but the blockage of ERK-1/2 by PD98059 rescued IS526-induced *** results suggested that IS526 regulates type Ⅱ collagen and MMP-13 expression via the ERK1/2 and PI-3K/Akt pathways in rabbit articular chondrocytes.

关键词： rice chondrocyte typeⅡcollagen matrix metalloproteinase-13 rice callus extract