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Within the proposed earlier model we study effects of stress σ 1 − σ 2 on the KD 2 PO 4 type ferroelectrics. In the cluster approximation for the short-range correlations, we calculate dielectric, piezoelectric, and elastic characteristics of a strained by σ 1 − σ 2 KD 2 PO 4 type crystal. Numerical analysis of the obtained results is performed. Stress dependences of the calculated characteristics and the phase diagram are explored. Possibility of the induced by σ 1 − σ 2 phase transition into a new paraelectric phase with monoclinic symmetry is discussed.

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We have performed Monte Carlo simulations in the canonical ensemble of a hard-sphere fluid adsorbed in microporous media. The pressure of the adsorbed fluid is calculated by using an original procedure that includes the calculations of the pressure tensor components during the simulation. In order to confirm the equivalence of bulk and adsorbed fluid pressures, we have exploited the mechanical condition of equilibrium and performed additional canonical Monte Carlo simulations in a super system "bulk fluid + adsorbed fluid". When the configuration of a model porous media permits each of its particles to be in contact with adsorbed fluid particles, we found that these pressures are equal. Unlike the grand canonical Monte Carlo method, the proposed calculation approach can be used efficiently to obtain adsorption isotherms over a wide range of fluid densities and porosities of adsorbent.

Within the model proposed earlier, we study the effect of hydrostatic pressure on relaxational dynamics of deuterated KD 2 PO 4 type ferroelectrics. Within the four particle approximation for deuteron ordering model and using the Glauber approach, we calculate the longitudinal dynamic dielectric permittivity of the strained crystal. Possible pressure dependences of the permittivity and relaxation times are discussed.