Small-amplitude dispersion oscillations on the background of the nonlinear geometric optic approximation

Analogues of the Pearcey integral describe the small dispersion influence on the beginning of spontaneous-vanishing processes for the nonlinear geometric optic approximation amplitude, which is a solution of equations of the focusing nonlinear Schrödinger equation type. The asymptotic behavior as x²+t²→∞ of these analogues is considered. For x²+t²→∞, the special functions under consideration have a domain of small-amplitude high-frequency oscillations, which occur on the background of the nonzero-amplitude nonlinear geometric optic approximation.     

On the solution of boundary-value problems of Kolmogorov-Petrovskii-Piskunov type

We describe a number of properties of solutions of boundary-value problems for nonlinear ordinary differential equations of the same type as those studied by Kolmogorov, Petrovskii, and Piskunov in their well-known paper on waves described by the parabolic equation. We construct and justify the asymptotics of such solutions for large values of the modulus of the independent variable.     

Wien effect in molten magnesium chloride

Results of studying the dependence of conductivity of molten magnesium chloride on the electric field intensity are presented. Limiting conductivities of the MgCl₂ melt are obtained that exceed the ordinary values by 265 and 253% at 1000 and 1040 K.     

Thermodynamics of Lanthanum Uranophosphate and Uranoarsenate

The enthalpies of formation at 298.15 K and the isobaric heat capacities in the range 80-300 K of lanthanum uranophosphate La(PUO₆)₃·14H₂O and lanthanum uranoarsenate La(AsUO₆)₃·15H₂O were measured, and the absolute entropy and Gibbs energy of formation of these compounds under standard conditions were calculated.     

Phenolic Compounds from Carthamus tinctorius

The contents of quercetin, luteolin, apigenin, isorhamnetin, umbelliferone, and daphnoretin in common safflower and of acacetin in the flowers were determined based on the physical and chemical properties of the isolated substances.     

Influence of frustrations on the thermodynamic properties of the low-dimensional Potts model studied by computer simulation

Influence of disorder in the form of frustration on the thermodynamic behavior of a two-dimensional three-vertex Potts model has been studied by the Monte Carlo method, taking into account the nearest and next-nearest neighbors. Systems with linear sizes of L × L = N (L = 9–48) on a triangular lattice have been considered. It has been shown that in the case of J₁ > 0 and J₂ < 0 frustrations appear in the spin system within the interval of 0.5 ≤ |r| ≤ 1.0. The model undergoes a phase transition outside this region.