Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Influence of shear stress $\sigma_6$ on the phase transition and
  physical properties of KD2PO4 type ferroelectrics   Within the four-particle cluster approximation for the proton ordering model
we study the influence of shear stress $\sigma_6$ on the phase transition,
static dielectric, elastic and thermal properties of deuterated KD2PO4 type
ferroelectrics. Thermodynamic potentials and physical characteristics of the
crystals in the presence of stress $\sigma_6$ are calculated. Numerical
analysis of the obtained results is performed, and the set of the theory
parameters providing the best fit to the available experimental data is found.
The $Tc-\sigma_6$ phase diagram is constructed; temperature dependences of the
calculated quantities are studied, possible stress dependences are indicated.
Influence of $\sigma_6$ stress is analogous to that of electric field conjugate
to the order parameter.

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The categories of this paper are: nucl-th
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The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org