The study of the parameters of capacitors with various working substances is of interest for the design and creation of electronic elements, in particular for the development of high-frequency phase-shifting circuits.

The purpose of the work is to calculate the high-frequency capacitance of a capacitor with the working substance "insulator-undoped silicon-insulator" at different applied to the capacitor direct current (DC) voltages, measuring signal frequencies and temperatures.

A model of such the capacitor is proposed, in which 30 µm thick layer of undoped (intrinsic) crystalline silicon (i-Si) is separated from each of the capacitor electrodes by 1 µm thick insulator layer (silicon dioxide).

The dependences of the capacitor capacitance on the DC electrical voltage U on metal electrodes at zero frequency and at the measuring signal frequency of 1 MHz at absolute temperatures T = 300 and 400 K are calculated. It is shown that the real part of the capacitor capacitance increases monotonically, while the imaginary part is negative and non-monotonically depends on U at the temperature T = 300 K. An increase in the real part of the capacitor capacitance up to the geometric capacitance of oxide layers with increasing temperature is due to a decrease in the electrical resistance of i-Si layer. As a result, with an increase in temperature up to 400 K, the real and imaginary parts of the capacitance take constant values independent of U. The capacitance of i-Si layer with an increase in both temperature T and voltage U is shunted by the electrical conductivity of this layer. The phase shift is determined for a sinusoidal electrical signal with a frequency of 0.3, 1, 10, 30, 100, and 300 MHz applied to the capacitor at temperatures 300 and 400 K.

The opened systems possess an increasing significance and possibilities of applying in designing of measuring devices. Now an essentially nonlinear models are used for such systems. The perturbation approach is not enough for these purposes. Models of new types have solutions in a form of soliton or kink and similar objects. The equation of Fisher–Kolmogorov–Petrovskii–Piskunov is one of such equations. This equation is used for description of convection-reaction-diffusion processes. Such processes are used for studying of a self-organisation and formation of a structure in non-equilibrium opened systems. The aim of this work was to construct of a new solution for the modified equation of Fisher–Kolmogorov– Petrovskii–Piskunov in which a space inhomogeneity is accounted.
To solve this problem the direct Hirota method for nonlinear partial differential equation is applied.
Some modifications into this method were introduced.
The new topologically non-trivial solution of the modified Fisher–Kolmogorov–Petrovskii–Piskunov equation is constructed explicitly. This solution has a kink-like form. Some arguments on the stability of such solution are considered.
A possibility of domain structure formation in the systems which describe by the Fisher–Kolmogorov– Petrovskii–Piskunov equation is demonstrated.

Improving the efficiency of ultrasonic control of hardened surface layers of metal products with a heterogeneous structure obtained using different technologies is a pressing problem of industrial production. The purpose of this work was to investigate the possibilities of measuring the depth of the surface inhomogeneous layer of steel objects on the basis of the use of amplitude and amplitude-angle characteristics of surface and subsurface transverse waves.

The analysis of ultrasonic methods of control of physical and mechanical properties of metals by using surface and subsurface waves and experimentally investigated amplitude-angular characteristics of surface waves, the maximum angle of which increases by 3° at change of dimensionless layer depth hλ from zero to

0.82. For the first time, the ratio of normalized amplitudes of surface waves taken at certain angles on the

amplitude-angle characteristic curve obtained in the echo mode was proposed to be used as correlating parameters with the depth of the hardened layer. As a result of this research, the possibility of using a phased array transducers to solve the above problems.

The effect of the hardened layer depth varying from zero to five in the working frequency range of 1.8– 10 MHz on the peculiarities of the refraction effect (including interference) and dependence of the subsurface wave amplitude on the acoustic base has been studied, making it possible to establish conditions that provide for the determination of the hardened layer depth.

Circuit solutions have been offered in order to increase the efficiency of control of properties of the surface layers of metal articles on the basis of utilization of small-aperture transducers and ultrasonic reflectors making it possible to form fields of surface waves of different directional pattern. 

Operation of modern flash memory elements is based on electron transport processes in the channel of silicon MOSFETs with floating gate. The aim of this work was calculation of electron mobility and study of the influence of phonon and ionized impurity scattering mechanisms on the mobility, as well as calculation of parasitic tunneling current and channel current in the conductive channel of flash memory element. Numerical simulation during the design stage of flash memory element allows working out guidelines for optimization of device parameters defining its performance and reliability.

In the work such electrophysical parameters, characterizing electron transport, as mobility and average electron energy, as well as tunneling current and current in the channel of the flash memory element are studied via the numerical simulation by means of Monte Carlo method. Influence of phonon and ionized impurity scattering processes on electron mobility in the channel has been analyzed. It is shown that in the vicinity of drain region a sufficient decrease of electron mobility defined by phonon scattering processes occurs and the growth of parasitic tunneling current is observed which have a negative influence on device characteristics.

The developed simulation program may be used in computer-aided design of flash memory elements for the purpose of their structure optimization and improvement of their electrical characteristics.

The paper presents a new view of vector physical quantities as multicomponent quantities. Each of the components of the mentioned multicomponent quantities can carry important and even unique information about the sources and causes of their occurrence. Looking at the vector quantity as the multicomponent quantity led to the need to form the corresponding conception. There are three positions of this conception in this paper, which are formulated as follows: vector multicomponent physical quantities are considered as functions of the set of their constituent information components; the communication functions of the specified information components in the models of multicomponent physical quantities are determined by the laws of vector algebra; information models of vector multicomponent physical quantities allow an alternative representation of information components depending on the selected coordinate system.

The mathematical model of the vector multicomponent physical quantity is presented. This model is fundamental and directly follows from the positions of the conception formulated above. This model can be applied to describe multicomponent displacements and deformations that both simple and complex objects undergo. An example of the complex object can be the manipulator of the universal industrial robot. The space for modeling multicomponent displacements of simple objects was shown in the paper. Information models of vector multicomponent physical quantities allow one to alternatively represent informative components. And the task of constructing such models is complex and ambiguous. Therefore, the formal apparatus for the synthesis of such models, which is based on certain rules and conventions, was proposed in the paper. The theoretical foundations of the method of optical measurements of informative components of multicomponent displacements and deformations of simple objects, which involves the use of multidimensional test objects, are presented.

Surface charge can be used as an information parameter about the change in the state of the material under the action of mechanical stresses. The aim of the work was to develop methods for studying deformation processes in metallic and polymeric materials using a charge-sensitive method.

Experimental studies of deformation processes under tensile, compressive and impact loads were carried out on samples of various materials: aluminum alloy of AMg2 grade, steel of grade 08PS, high-pressure polyethylene of grade 12203-250 and samples of composite materials based on it, F4 polytetrafluoroethylene. As a research method, the analysis of changes in the relative values of the surface electron work function in the case of metals and the surface electrostatic potential in the case of polymers and composite materials is used. A scanning modification of a charge-sensitive probe is used as a measuring instrument.

The results of experimental studies of materials in a stress-strain state demonstrate the high efficiency of the proposed method. The research methodology makes it possible to detect local changes in the surface potential of the material in the area of deformations, which are not detected on a macroscopic scale using standard methods. The results obtained can serve as a basis for the development of new methods and techniques for studying the mechanical properties of both metals and dielectric materials.

The highest quality and timely diagnostics of windings’ state of various types of electrical machines including of asynchronous motors’ windings is an impoitant task. Among the existing diagnostic methods currently the most promising are those ones based on methods for analyzing resonance processes occurring in electrical machines. The aim of the article was to assess the possibility of use resonant processes occurring in electrical machines for qualitative diagnostics of their windings state using the asynchronous motors example, to build mathematical models that allow describing defect formation in windings and to analyze the deviation of mathematical models relative to the results obtained.

Analysis of the influence of the level of interturn resistances, the number of closed turns and the location of closed turns in sections on the phase-frequency characteristics of asynchronous motors windings of various classes has been carried out. Mathematical models of the phase-frequency characteristics are obtained, coefficients of polynomials are determined and the relative discrepancy between these mathematical dependences relative to the experimental data is estimated depending on the considered parameters characterizing defects in the coils’ windings of electrical machines.

Obtained mathematical models and coefficients for them can serve as the basis for construction of automated control and diagnostic systems for checking of the windings state of electrical machines including assessing the residual life of their work.