Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase transitions and crossovers in reaction-diffusion models with
  catalyst deactivation   The activity of catalytic materials is reduced during operation by several
mechanisms, one of them being poisoning of catalytic sites by chemisorbed
impurities or products. Here we study the effects of poisoning in two
reaction-diffusion models in one-dimensional lattices with randomly distributed
catalytic sites. Unimolecular and bimolecular single-species reactions are
considered, without reactant input during the operation. The models show
transitions between a phase with continuous decay of reactant concentration and
a phase with asymptotic non-zero reactant concentration and complete poisoning
of the catalyst. The transition boundary depends on the initial reactant and
catalyst concentrations and on the poisoning probability. The critical system
behaves as in the two-species annihilation reaction, with reactant
concentration decaying as t^{-1/4} and the catalytic sites playing the role of
the second species. In the unimolecular reaction, a significant crossover to
the asymptotic scaling is observed even when one of those parameters is 10% far
from criticality. Consequently, an effective power-law decay of concentration
may persist up to long times and lead to an apparent change in the reaction
kinetics. In the bimolecular single-species reaction, the critical scaling is
followed by a two-dimensional rapid decay, thus two crossovers are found.

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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys