1,442 research outputs found

    Size Estimation of Interface Crack by Interference Effect

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    It is of primary importance to estimate the crack size on the interface of two solids for evaluating the integrity of jointed interfaces. In this paper, the scattering problem of elastic waves is formulated for the interface crack of layered materials in water. Green’s function for the water/solid/solid material is constructed and utilized to represent the scattered pressure field in water caused by the crack opening displacement in the interface of two solids. Introduction of the far-field approximation for the scattered pressure field and then the high frequency approximation for the crack opening displacement leads to a simple equation which is related to the crack size, the wave velocity in water, the angles of incident wave and observation point, and the period of scattering amplitude in the frequency range. The size of interface crack is estimated by measuring the periodicity of the scattering amplitude for fixed transducer’s angles in water. Examples are shown for pulse-echo configurations

    Evidence of Strong Correlation between Instanton and QCD-monopole on SU(2) Lattice

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    The correlation between instantons and QCD-monopoles is studied both in the lattice gauge theory and in the continuum theory. An analytical study in the Polyakov-like gauge, where A4(x)A_4(x) is diagonalized, shows that the QCD-monopole trajectory penetrates the center of each instanton, and becomes complicated in the multi-instanton system. Using the SU(2) lattice with 16416^4, the instanton number is measured in the singular (monopole-dominating) and regular (photon-dominating) parts, respectively. The monopole dominance for the topological charge is found both in the maximally abelian gauge and in the Polyakov gauge.Comment: 4 pages, Latex, 3 figures. Talk presented by H. Suganuma at International Symposium on 'Lattice Field Theory', July 11 - 15, 1995, Melbourne, Australi

    Confinement and Topological Charge in the Abelian Gauge of QCD

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    We study the relation between instantons and monopoles in the abelian gauge. First, we investigate the monopole in the multi-instanton solution in the continuum Yang-Mills theory using the Polyakov gauge. At a large instanton density, the monopole trajectory becomes highly complicated, which can be regarded as a signal of monopole condensation. Second, we study instantons and monopoles in the SU(2) lattice gauge theory both in the maximally abelian (MA) gauge and in the Polyakov gauge. Using the 163×416^3 \times 4 lattice, we find monopole dominance for instantons in the confinement phase even at finite temperatures. A linear-type correlation is found between the total monopole-loop length and the integral of the absolute value of the topological density (the total number of instantons and anti-instantons) in the MA gauge. We conjecture that instantons enhance the monopole-loop length and promote monopole condensation.Comment: 3 pages, LaTeX, Talk presented at LATTICE96(topology

    Cardiac rupture after catheter ablation procedure

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    ArticleAnnals of Thoracic Surgery. 80(1): 326-328 (2005)journal articl

    Lifshitz-Slyozov Scaling For Late-Stage Coarsening With An Order-Parameter-Dependent Mobility

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    The coarsening dynamics of the Cahn-Hilliard equation with order-parameter dependent mobility, λ(ϕ)∝(1−ϕ2)α\lambda(\phi) \propto (1-\phi^2)^\alpha, is addressed at zero temperature in the Lifshitz-Slyozov limit where the minority phase occupies a vanishingly small volume fraction. Despite the absence of bulk diffusion for α>0\alpha>0, the mean domain size is found to grow as ∝t1/(3+α) \propto t^{1/(3+\alpha)}, due to subdiffusive transport of the order parameter through the majority phase. The domain-size distribution is determined explicitly for the physically relevant case α=1\alpha = 1.Comment: 4 pages, Revtex, no figure

    Human Ό-calpain: Simple isolation from erythrocytes and characterization of autolysis fragments

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    Heterodimeric ÎŒ-calpain, consisting of the large (80 kDa) and the small (30 kDa) subunit, was isolated and purified from human erythrocytes by a highly reproducible four-step purification procedure. Obtained material is more than 95% pure and has a specific activity of 6 - 7 mU/mg. Presence of contaminating proteins could not be detected by HPLC and sequence analysis. During storage at -80 °C the enzyme remains fully activatable by CaÂČâș, although the small subunit is partially processed to a 22 kDa fragment. This novel autolysis product of the small subunit starts with the sequence (60)RILG and is further processed to the known 18 kDa fragment. Active forms and typical transient and stable autolysis products of the large subunit were identified by protein sequencing. In casein-zymograms only the activatable forms 80 kDa+30 kDa, 80 kDa+22 kDa and 80 kDa+18 kDa displayed caseinolysis

    Instanton, Monopole Condensation and Confinement

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    The confinement mechanism in the nonperturbative QCD is studied in terms of topological excitation as QCD-monopoles and instantons. In the 't Hooft abelian gauge, QCD is reduced into an abelian gauge theory with monopoles, and the QCD vacuum can be regarded as the dual superconductor with monopole condensation, which leads to the dual Higgs mechanism. The monopole-current theory extracted from QCD is found to have essential features of confinement. We find also close relation between monopoles and instantons using the lattice QCD. In this framework, the lowest 0++0^{++} glueball (1.5 ∌\sim 1.7GeV) can be identified as the QCD-monopole or the dual Higgs particle.Comment: Talk presented by H.Suganuma at the 5th Topical Seminar on The Irresistible Rise of the Standard Model, San Miniato al Todesco, Italy, 21-25 April 1997 5 pages, Plain Late

    Critical dynamics of phase transition driven by dichotomous Markov noise

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    An Ising spin system under the critical temperature driven by a dichotomous Markov noise (magnetic field) with a finite correlation time is studied both numerically and theoretically. The order parameter exhibits a transition between two kinds of qualitatively different dynamics, symmetry-restoring and symmetry-breaking motions, as the noise intensity is changed. There exist regions called channels where the order parameter stays for a long time slightly above its critical noise intensity. Developing a phenomenological analysis of the dynamics, we investigate the distribution of the passage time through the channels and the power spectrum of the order parameter evolution. The results based on the phenomenological analysis turn out to be in quite good agreement with those of the numerical simulation.Comment: 27 pages, 12 figure
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