122 research outputs found
ON CORRELATION BETWEEN SURFACE STRUCTURE AND CATALYTIC ACTIVITY OF AMORPHOUS ALLOYS
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
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
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
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.
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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