3,661 research outputs found

    Enthalpy relaxation and microstructure evolution in hyperquenched SiO2–Al2O3-ZrO2 system

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    Finite Volume Effect of Nucleons and the Formation of the Quark-Gluon Plasma

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    We study a thermodynamically consistent implementation of the nucleon volume in the mean field theory, and find that this volume has large consequences on the properties of hadronic matter under extreme conditions such as in astrophysical objects and high energy heavy-ion collisions. It is shown that we can reproduce the critical temperature Tc200T_{c}\simeq 200 MeV predicted by lattice QCD calculations for the phase transition from hadronic matter to quark-gluon plasma, by using parameters which are adjusted to fit all empirical data for normal nuclear matter.Comment: 11 Latex pages, 4 figures upon reques

    Robust fault detection for networked systems with communication delay and data missing

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    n this paper, the robust fault detection problem is investigated for a class of discrete-time networked systems with unknown input and multiple state delays. A novel measurement model is utilized to represent both the random measurement delays and the stochastic data missing phenomenon, which typically result from the limited capacity of the communication networks. The network status is assumed to vary in a Markovian fashion and its transition probability matrix is uncertain but resides in a known convex set of a polytopic type. The main purpose of this paper is to design a robust fault detection filter such that, for all unknown inputs, possible parameter uncertainties and incomplete measurements, the error between the residual signal and the fault signal is made as small as possible. By casting the addressed robust fault detection problem into an auxiliary robust H∞ filtering problem of a certain Markovian jumping system, a sufficient condition for the existence of the desired robust fault detection filter is established in terms of linear matrix inequalities. A numerical example is provided to illustrate the effectiveness and applicability of the proposed technique

    Amplitude analysis of e+e−→VP with the CLEO measurements

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    AbstractWith the measured cross sections for e+e−→vector–pseudoscalar (VP) at s=3.773 GeV and s=3.671 GeV by the CLEO Collaboration, we perform a global amplitude analysis to study the possible interference effects between the continuum process via virtual photon and the ψ(3770) resonance decay. It is found that such interference may significantly affect the measurement of the ψ(3770)→exclusive non-DD¯ decays. By taking the interference into account, we extract the branching fraction for ψ(3770)→ρπ

    Solution Of Wheeler-De Witt Equation, Potential Well And Tunnel Effect

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    This paper uses the relation of the cosmic scale factor and scalar field to solve Wheeler-DeWitt equation, gives the tunnel effect of the cosmic scale factor a and quantum potential well of scalar field, and makes it fit with the physics of cosmic quantum birth. By solving Wheeler-DeWitt equation we achieve a general probability distribution of the cosmic birth, and give the analysis of cosmic quantum birth.Comment: 12 page

    Statistics of skyrmions in Quantum Hall systems

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    We analyze statistical interactions of skyrmions in the quantum Hall system near a critical filling fraction in the framework of the Ginzburg-Landau model. The phase picked up by the wave-function during an exchange of two skyrmions close to ν=1/(2n+1)\nu=1/(2n+1) is π[S+1/2(2n+1)]\pi[S+1/2(2n+1)], where SS is the skyrmion's spin. In the same setting an exchange of two fully polarized vortices gives rise to the phase π/(2n+1)\pi/(2n+1). Skyrmions with odd and even numbers of reversed spins have different quantum statistics. Condensation of skyrmions with an even number of reversed spins leads to filling fractions with odd denominators, while condensation of those with an odd number of reversed spins gives rise to filling fractions with even denominators.Comment: 6 pages in Latex. addendum - skyrmions with odd or even number of reversed spins have different quantum statistics. They condense to form respectively even or odd denominator filling fraction state

    Generation of solitary waves by transcritical flow over a step

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    It is well-known that transcritical flow over a localised obstacle generates upstream and downstream nonlinear wavetrains. The flow has been successfully modeled in the framework of the forced Korteweg-de Vries equation, where numerical and asymptotic analytical solutions have shown that the upstream and downstream nonlinear wavetrains have the structure of unsteady undular bores, connected by a locally steady solution over the obstacle, which is elevated on the upstream side and depressed on the downstream side. In this paper we consider the analogous transcritical flow over a step, primarily in the context of water waves. We use numerical and asymptotic analytical solutions of the forced Korteweg-de Vries equation, together with numerical solutions of the full Euler equations, to demonstrate that a positive step generates only an upstream-propagating undular bore, and a negative step generates only a downstream-propagating undular bore

    Generation of internal undular bores by transcritical flow over topography

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    In both the ocean and the atmosphere, the interaction of a density stratified flow with topography can generate large-amplitude, horizontally propagating internal solitary waves. Often these waves appear as a wave-train, or undular bore. In this article we focus on the situation when the flow is critical, that is, the flow speed is close to that of a linear long wave mode. In the weakly nonlinear regime, this is modeled by the forced Korteweg de Vries equation. We will demonstrate how Whitham’s modulation theory may be applied to obtain an analytical description of undular bores, for flow over isolated obstacles and for flow over a step
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