Vol 59, No 5 (2016)

Using the Monte Carlo approach, special features of structural and energy characteristics of β-brass are investigated under cycling conditions. As a result of the heating-cooling cycle, a unique hysteresis loop is observed, which suggests irreversibility of the processes and implies differences in the structural-phase states in the heating and cooling stages. An analysis of the atomic and phase structure of the system during heating and cooling, i.e., in the course of order–disorder and disorder–order phase transitions, has demonstrated that the system is found in different structural–phase states. Upon completion of the disorder–order phase transition, two domains of the B2 superstructure are formed.

Effect of orientation of the induced uniaxial magnetic anisotropy axis on the temperature dependences of the ΔE-effect for ribbons having Fe₆₄Co₂₁B₁₅ amorphous metal alloy composition after thermomagnetic treatment at temperatures from 270 to 330°C is investigated. The magnetic field strength at which the absolute value of the negative ΔE-effect is maximal decreases with increasing tilt angle of the induced uniaxial magnetic anisotropy axis with respect to the direction perpendicular to the ribbon rolling axis. This decrease is caused by the decrease in the field of the Bloch–Néel transition of charged domain walls during magnetization of the ribbon with a tilted easy magnetization axis.

The process of introduction of submicron agglomerates and nanostructured particles into a poorly wetting liquid exposed to ultrasound is theoretically considered. The main dependences relating the exposure time to the physical and chemical properties of particles and liquid as well as to the characteristics of acoustic radiation are obtained.

A flow of physical events (photons, electrons, etc.) is considered. One of the mathematical models of such flows is the MAP flow of events. Analytical results for conditional and unconditional probabilities of erroneous decision in optimal estimation of states of the MAP flow of events are presented.

Composite models of heavy leptons and their corresponding neutrinos are proposed, generalizing the known Di Vecchia–Ravndal supersymmetric relativistic model of the electron. A model interpretation of Barut’s empirical formula for the masses of heavy leptons is made. It is proposed to use a composite model to explain differences in the interaction of a muon and an electron with a proton. An estimate for neutrino masses is given.

Dispersive transport of charge carriers in a two-layer polymer structure is modeled on the basis of the integrodifferential equation of hereditary diffusion. The model of multiple trapping in a bilayer is generalized to the case of an arbitrary density of localized states. With the help of an efficient Monte Carlo algorithm, curves of the transient current are calculated and their features are explained within the framework of a stochastic interpretation of the process.

Scattering elements of the medium are point electric and magnetic dipoles. The medium consists of planeparallel electric and magnetic dipole monolayers. The fields of the dipoles are completely taken into account. The field within the medium and the reflected one are calculated. The microscopic analysis of the extinction theorem is conducted. Expressions for Fresnel coefficients are obtained. The mechanism of rotation of the magnetic field polarization vector during refraction is elucidated. A reason for the absence of the expression for the fourth wave propagating from the medium to the interface in conventionally used interface conditions is elucidated. The possibility of obtaining media with unity and zero refractive indices is substantiated.

The absorption spectra of ferrospinel single crystal films obtained by the method of chemical transport reactions are considered. It is demonstrated that along with a homogeneous resonance, additional absorption peaks corresponding to exchange spin modes localized in the surface layer are observed in the absorption spectrum investigated with an EPR spectrometer in the case of perpendicular orientation of the film with respect to an external static magnetic field. Resonant interaction of magnetostatic oscillations with exchange spin modes in the surface layer is detected in the case of tangent magnetization. The width of the magnetostatic layer and the ranges of existence of the surface and volume modes depend on the relationship between the constants of uniaxial surface anisotropy and crystallographic magnetic anisotropy. The wave numbers of the magnetostatic and exchange spin modes, the parameters of inhomogeneous exchange, and the effective magnon masses are calculated.

A flow of physical events (photons, electrons, and other elementary particles) is studied. One of the mathematical models of such flows is the modulated MAP flow of events circulating under conditions of unextendable dead time period. It is assumed that the dead time period is an unknown fixed value. The problem of estimation of the dead time period from observations of arrival times of events is solved by the method of maximum likelihood.

The spectral and luminescent properties of the laurdan molecule (6-dodecanol 2-dimethylamino-naphthalene) are investigated by experimental and theoretical methods of time-dependent density functional theory (TDDFT). The fluorescence spectra of laurdan in homogeneous and binary solvents are analyzed using derivative spectroscopy method. It is shown that the fluorescence band (in hexane, cyclohexane, and triton X-100) is complex: two structures having energy difference 1000–1500 cm^–1 are manifested for the molecule. The calculated data show the non-rigidity of its structure. The effect of proton-donor solvents is considered with allowance for not only dipole-dipole interactions, but also formation of the hydrogen bond.

It is shown that there exist solutions for which the linear differential equations of physics are transformed into nonlinear equations. The corresponding diffusion Maxwellian solution of the equation of magnetic induction in a moving medium can be used to describe the emergence and subsequent evolution of the magnetic fields of the Earth, Sun, and other planets and stars. If the magnetic viscosity is complex, the evolution of the magnetic induction is cyclic, in which case the magnetic induction can change sign.

A new phenomenon is observed in a spark discharge developing under normal conditions in air in a discharge circuit with a capacitive decoupling. It consists in the current channel bending becoming a source of a 4–6 cm long plasma jet directed across the channel. The phenomenon is termed an apokampic discharge or an apokamp. Its emission spectrum contains the bands of electron-vibration transitions from the second positive group of molecular nitrogen. The conditions of formation of an apokamp are experimentally determined. A conclusion is drawn that in order construct a physical model of an apokamp, one has to take into account: 1) the presence of a local gas overheating in the site of the current channel bending, 2) the similarity of the current and voltage time dependences in the corona discharge and in the current channel (becoming a source of an apokamp), and 3) the length of the apokamp plasma jet.

We study symmetry peculiarities of crystalline compounds of a cubic system with the space groups T⁴ and T⁵ caused by the absence of point Wyckoff-sets in the unit cells of these groups. Due to the high multiplicity of the available Wyckoff positions, such compounds possess unit cells of complex composition. In these compounds, pseudosymmetry is realized with high probability when some group of atoms is located in positions close to the positions of higher-symmetry groups. We provide examples of crystalline compounds showing predicted specific structural features.