8,364 research outputs found

    The invariant imbedding equation for the dissipation function of a homogeneous finite slab

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    Differential-integral equation for dissipation function and derivation of conservation relationship connecting reflection, transmission and dissipation functions of finite sla

    The Additional Symmetries for the BTL and CTL Hierarchies

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    The Toda lattice (TL) hierarchy was first introduced by K.Ueno and K.Takasaki in \cite{uenotaksasai} to generalize the Toda lattice equations\cite{toda}. Along the work of E. Date, M. Jimbo, M. Kashiwara and T. Miwa \cite{DJKM} on the KP hierarchy, K.Ueno and K.Takasaki in \cite{uenotaksasai} develop the theory for the TL hierarchy: its algebraic structure, the linearization, the bilinear identity, τ\tau function and so on. Also the analogues of the B and C types for the TL hierarchy, i.e. the BTL and CTL hierarchies, are considered in \cite{uenotaksasai}, which are corresponding to infinite dimensional Lie algebras o()\textmd{o}(\infty) and sp()\textmd{sp}(\infty) respectively. In this paper, we will focus on the study of the additional symmetries for the BTL and CTL hierarchies.Comment: 13 page

    Diagnostico coprologico quantitativo da fasciolose de ruminantes no Rio Grande do Sul.

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    Foram coletadas 158 amostras de fezes de bovinos e 164 de ovinos em cinco municipios do Estado do Rio Grande do Sul, onde ocorre fasciolose giagnosticada atraves de dados de matadouros. Em todas as amostras, empregaram-se a tecnica de quatro tamises (Girao 1982) e a de Dennis et al. (1954), totalizando 644 exames. A percentagem de amostras fecais de bovinos e ovinos nas quais foram detectados ovos de Fasciola hepatica pelas tecnicas de quatro tamises e Dennis, foi de 45,6% e 43,7% em bivinos e de 61,6% e 57,9% em ovinos, respectivamente, nao havendo, portanto, diferenca significaiva entre as duas tecnicas

    Critical Casimir effect and wetting by helium mixtures

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    We have measured the contact angle of the interface of phase-separated 3^{3}He-4^{4}He mixtures against a sapphire window. We have found that this angle is finite and does not tend to zero when the temperature approaches TtT_t, the temperature of the tri-critical point. On the contrary, it increases with temperature. This behavior is a remarkable exception to what is generally observed near critical points, i.e. "critical point wetting''. We propose that it is a consequence of the "critical Casimir effect'' which leads to an effective attraction of the 3^{3}He-4^{4}He interface by the sapphire near TtT_{t}.Comment: submitted july 13 (2002), published march 20 (2003

    Analytic-bilinear approach to integrable hierarchies. II. Multicomponent KP and 2D Toda lattice hierarchies

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    Analytic-bilinear approach for construction and study of integrable hierarchies is discussed. Generalized multicomponent KP and 2D Toda lattice hierarchies are considered. This approach allows to represent generalized hierarchies of integrable equations in a condensed form of finite functional equations. Generalized hierarchy incorporates basic hierarchy, modified hierarchy, singularity manifold equation hierarchy and corresponding linear problems. Different levels of generalized hierarchy are connected via invariants of Combescure symmetry transformation. Resolution of functional equations also leads to the τ\tau -function and addition formulae to it.Comment: 43 pages, Late

    3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

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    We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occuring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When applied to a specific SNR, our model will predict cosmic-ray spectra and multi-wavelength morphology in projected images for instruments with varying spatial and spectral resolutions. We show examples of these spectra and images and emphasize the importance of measurements in the hard X-ray, GeV, and TeV gamma-ray bands for investigating key ingredients in the acceleration mechanism, and for deducing whether or not TeV emission is produced by IC from electrons or neutral pions from protons.Comment: 12 pages, 9 figures, accepted by Apj, 24 June 200

    Quench Protection of DI-BSCCO Coil

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    AbstractQuench protection is one of the most important requirements for the practical application of high-temperature-superconducting (HTS) coils. Quench protection requires that early detection of a developing quench event is followed by rapid reduction of the operating current. However, such quench detection is very difficult because HTS wire produces heat only locally due to the very slow propagation velocity of a normal zone. Excellent high voltage insulation performance is required if the current is to be reduced rapidly in a large-scale superconducting application with very large inductance. Thus it is important to investigate the behavior of coils with various decay time constants, and to detect voltages on very short time scales. This goal remains to be achieved. In the present study we built test coil and a full-scale pole coil for a 20 MW motor for use in experiments on quench protection, and parameterized the relation between the decay time constant and the detecting voltage, using a conventional balance circuit to detect the quench, which was generated by gradually raising the temperature of the coils. The results verify that a balance circuit can be used for quench detection. For example, when the current decay time constant is 4seconds, the test coil can be protected even with a detecting voltage of 0.15 volts, despite a significant heat production rate of 126W. We also confirmed that the full-scale pole coil, with a decay time constant of 20seconds, can be protected with a detecting voltage of 0.06V

    Seleção e clonagem de porta-enxertos tolerantes à morteprecoce do pessegueiro.

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