A model of coupled resonators for calculating the electromagnetic wave diffraction on planar one-dimensional Bragg gratings

The problem of excitation of a one-dimensional planar Bragg grating is studied. A model of coupled resonators is proposed for investigating the diffraction of electromagnetic waves on a waveguide surface with arbitrary corrugation profile. The model is based on the strict relationships derived from a solution to a two-dimensional boundary problem for the Helmholtz equation. A particular form of equations is presented for the case of a rectangular corrugation of plates in the grating.     

A study of elastic force and surface damping on an atomic-force microscope functioning in a semi-contact mode

An approach that makes it possible to study the elastic forces of a surface and surface damping from the results of measurements taken by an atomic force microscope functioning in semi-contact mode is proposed. An analytic relation between the measured quantities, on the one hand, and the elastic force of the surface and surface damping, on the other hand, is obtained.     

Tensor method and dual networks in electrical engineering

The development of Kron’s tensor method based on a duality invariant yields a principle of energy flow conservation and methods for calculating circuits and network models of complex systems with variable structures, including electric models of economic systems.     

Microwave absorbing properties of Fe powders milled in various media

Principal factors determining the microwave-absorption material parameters (shape, size, and chemical and phase compositions of the particles) and their dispersion relations in a range from 0.1 to 3 GHz were determined for composites containing milled Fe particles as the filling agent. The basic physical mechanisms of the effect of the aforementioned factors were assumed to be the domain-wall resonance and ferromagnetic resonance.     

On the fractal nature of light-emitting structures based on III–N nanomaterials and related phenomena

It is shown that a three-dimensional fractal–percolation system is formed in nanomaterials of light-emitting InGaN/GaN and AlGaN/GaN structures in the presence of conducting extended defects and local inhomogeneities of the composition of the solid solutions; this system determines the electrophysical properties of light-emitting diodes fabricated on the basis of these structures. The geometry and properties of this system depend nonlinearly on the degree of disorder in the nanomaterial of the structures, on the value of the injection current, and on the rate of alloy growth.     

The airflow effect on a negative corona discharge

The effect of the airflow on the negative corona discharge is studied. It is shown by use of telemicroscopy that the localization of the discharge torch on the cathode surface can be significantly affected by the aerodynamic action on the discharge gap region.