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101.
102.
Raimund Bürger Hermano Frid Kenneth H. Karlsen 《Journal of Mathematical Analysis and Applications》2007,326(1):108-120
We study a zero-flux type initial-boundary value problem for scalar conservation laws with a genuinely nonlinear flux. We suggest a notion of entropy solution for this problem and prove its well-posedness. The asymptotic behavior of entropy solutions is also discussed. 相似文献
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Abstract. Rupture of a light cellophane diaphragm in an expansion tube has been studied by an optical method. The influence of the
light diaphragm on test flow generation has long been recognised, however the diaphragm rupture mechanism is less well known.
It has been previously postulated that the diaphragm ruptures around its periphery due to the dynamic pressure loading of
the shock wave, with the diaphragm material at some stage being removed from the flow to allow the shock to accelerate to
the measured speeds downstream. The images obtained in this series of experiments are the first to show the mechanism of diaphragm
rupture and mass removal in an expansion tube. A light diaphragm was impulsively loaded via a shock wave and a series of images
was recorded holographically throughout the rupture process, showing gradual destruction of the diaphragm. Features such as
the diaphragm material, the interface between gases, and a reflected shock were clearly visualised. Both qualitative and quantitative
aspects of the rupture dynamics were derived from the images and compared with existing one-dimensional theory.
Received 10 April 1999 / Accepted 17 April 2000 相似文献
107.
In this paper we define odd dimensional unitary groups . These groups contain as special cases the odd dimensional general linear groups where R is any ring, the odd dimensional orthogonal and symplectic groups and where R is any commutative ring and further the first author's even dimensional unitary groups where is any form ring. We classify the E-normal subgroups of the groups (i.e. the subgroups which are normalized by the elementary subgroup ), under the condition that R is either a semilocal or quasifinite ring with involution and . Further we investigate the action of by conjugation on the set of all E-normal subgroups. 相似文献
108.
Mostafa Bendahmane Raimund Bürger Ricardo Ruiz‐Baier 《Numerical Methods for Partial Differential Equations》2010,26(6):1377-1404
The bidomain model of electrical activity of myocardial tissue consists of a possibly degenerate parabolic PDE coupled with an elliptic PDE for the transmembrane and extracellular potentials, respectively. This system of two scalar PDEs is supplemented by a time‐dependent ODE modeling the evolution of the gating variable. In the simpler subcase of the monodomain model, the elliptic PDE reduces to an algebraic equation. Since typical solutions of the bidomain and monodomain models exhibit wavefronts with steep gradients, we propose a finite volume scheme enriched by a fully adaptive multiresolution method, whose basic purpose is to concentrate computational effort on zones of strong variation of the solution. Time adaptivity is achieved by two alternative devices, namely locally varying time stepping and a Runge‐Kutta‐Fehlberg‐type adaptive time integration. A series of numerical examples demonstrates that these methods are efficient and sufficiently accurate to simulate the electrical activity in myocardial tissue with affordable effort. In addition, the optimal choice of the threshold for discarding nonsignificant information in the multiresolution representation of the solution is addressed, and the numerical efficiency and accuracy of the method is measured in terms of CPU time speed‐up, memory compression, and errors in different norms. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010 相似文献
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A. Breakstone C. D. Buchanan R. Campanini H. B. Crawley M. Dallavalle K. Doroba D. Drijard F. Fabbri A. Firestone H. G. Fischer H. Frehse W. Geist G. Giacomelli R. Gokieli M. Gorbics P. Hanke M. Heiden W. Herr E. E. Kluge J. W. Lamsa T. Lohse W. T. Meyer G. Mornacchi T. Nakada M. Panter A. Putzer K. Rauschnabel F. Rimondi R. Sosnowski M. Szczekowski O. Ullaland D. Wegener 《Zeitschrift fur Physik C Particles and Fields》1984,25(1):21-27
High energy proton-proton interactions yielding a single trigger particle with large transverse momentum give rise to a four-jet event structure with two transverse jets and two jets along the beam direction. The transverse jets are due to the fragmentation of point like scattered partons. It is shown that the quantum numbers of triggering charged pions and positive kaons are correlated with the flavour of the scattered parent parton; thus one can enhance data samples with a particular flavour of a scattered parton. The analysis, which is independent of detailed model calculations, exploits (a) the identification of the leading particles in the trigger jets (trigger particles), (b) the measurement of their relative production rates, (c) short range quantum number correlations within the trigger jets, and (d) long range correlations between leading particles from different jets. The data were obtained at \(\sqrt s \) =62 GeV with the Split Field Magnet detector at the CERN ISR. 相似文献