122 research outputs found

    BESTIMMUNG DER LÖSLICHKEIT VON GASEN UND GASGEMISCHEN

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    COMPARATIVE STUDIES ON THE DETERMINATION OF SPECIFIC SURFACE AREAS BY LIQUID ADSORPTION

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    ON CORRELATION BETWEEN SURFACE STRUCTURE AND CATALYTIC ACTIVITY OF AMORPHOUS ALLOYS

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    The present paper is a review summarizing our results gained in the field of catalysis over amorphous alloys. The route leading to the formation of the catalytically active phase is presented and the factors which may play a decisive role in this process is discussed. Following the surface characterization of amorphous alloys led to the constructions of a surface model its modifying effects are described. Their catalytic properties are further influenced by the structure and the morphology. These parameters are crucial to the formation of the active metal ensembles and to the behaviour of reactants over the surface. These factors are discussed in detail for the utilization of amorphous alloys, primarily as catalyst precursors

    Relativistic diffusive motion in random electromagnetic fields

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    We show that the relativistic dynamics in a Gaussian random electromagnetic field can be approximated by the relativistic diffusion of Schay and Dudley. Lorentz invariant dynamics in the proper time leads to the diffusion in the proper time. The dynamics in the laboratory time gives the diffusive transport equation corresponding to the Juettner equilibrium at the inverse temperature \beta^{-1}=mc^{2}. The diffusion constant is expressed by the field strength correlation function (Kubo's formula).Comment: the version published in JP

    Relativistic diffusion of elementary particles with spin

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    We obtain a generalization of the relativistic diffusion of Schay and Dudley for particles with spin. The diffusion equation is a classical version of an equation for the Wigner function of an elementary particle. The elementary particle is described by a unitary irreducible representation of the Poincare group realized in the Hilbert space of wave functions in the momentum space. The arbitrariness of the Wigner rotation appears as a gauge freedom of the diffusion equation. The spin is described as a connection of a fiber bundle over the momentum hyperbolic space (the mass-shell). Motion in an electromagnetic field, transport equations and equilibrium states are discussed.Comment: 21 pages,minor changes,the version published in Journ.Phys.

    Relativistic diffusion with friction on a pseudoriemannian manifold

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    We study a relativistic diffusion equation on the Riemannian phase space defined by Franchi and Le Jan. We discuss stochastic Ito (Langevin) differential equations (defining the diffusion) as a perturbation by noise of the geodesic equation. We show that the expectation value of the angular momentum and the energy grow exponentially fast. We discuss drifts leading to an equilibrium. It is shown that the diffusion process corresponding to the Juettner or quantum equilibrium distributions has a bounded expectation value of angular momentum and energy. The energy and the angular momentum tend exponentially fast to their equilibrium values. As examples we discuss a particle in a plane fronted gravitational wave and a particle in de Sitter universe. It is shown that the relativistic diffusion of momentum in de Sitter space is the same as the relativistic diffusion on the Minkowski mass-shell with the temperature proportional to the de Sitter radius.Comment: the version published in CQ

    On the algebraic structure of conditional events: 13th European conference, ECSQARU 2015, Compiègne, France, July 15-17, 2015.

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    This paper initiates an investigation of conditional measures as simple measures on conditional events. As a first step towards this end we investigate the construction of conditional algebras which allow us to distinguish between the logical properties of conditional events and those of the conditional measures which we can be attached to them. This distinction, we argue, helps us clarifying both concepts
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