ISSN 2224-087X (Print)
ISSN 2224-0888 (Online)

Collected scientific papers
"Electronics and information technologies"

(In 1966-2010 published under the title "Electrical engineering")

(Certificate of State Registration 17618-6468 from February 11, 2011)

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Issue 5

Issue 5, Pages: 3-21
The size effect in dielectric crystals with incommensurate phase
I. Karpa, S. Sveleba, I. Katerynchuk, I. Kunyo, O. Fitsych
The current status of the size effects study in crystals of A2BX4 with incommensurate superstructure is considered in this paper. Different manifestations of size effects are described, including the influence of the order parameter amplitude, of the rate of relaxation of metastable states, of the magnitude of global temperature hysteresis, of the optical birefringence depended to value of the transverse sample dimensions. Also the appearance of jump-like temperature dependence of birefringence and the increase of anomalous hysteresis values at of the phase transition temperature incommensurate - commensurate phase is considered. Inconsistency linear expansion coefficients of the substrate crystal and causes the appearance of mechanical stresses. The magnitude of these stress increases with decreasing size of the crystal. As a result, the expansion temperature range of incommensurate phase and reduce the IC wavelength modulation is observed. In crystals 24 group with incommensurate phases the following size effects is found: the increase of temperature hysteresis phase transition at Tc, and T3, because of the increase in value of the effective parameter of electrostriction; disappearance of the global temperature hysteresis, due to the increase of inhomogeneous deformation in the IC, this is accompanied by a decrease of the correlation length IC structure, leading to lower the barrier for phase slip. Not only the period incommensurate modulation is changed, but also the value of the order parameter amplitude modulation is reduced according to reduced sample crystal thickness along the axis incom-mensurate modulation to the size of the period of incommensurate superstructure.
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Issue 5, Pages: 22-32
The band structure of Rb2ZnCl4 crystals in paraelectric phase
V. urlyak, O. Bovgyra, V.Stadnyk, .tviishyn, V. Stakhura, L.-D. Karpluk
On the basis of self-consistently calculation a framework of the density functional theory using the ultra-soft pseudopotentials and different approximations for description of potential of electron-electronic interaction (LDA GGA) the band-power diagrams and distributions of electronic states of Rb2ZnCl4 crystals are determined in a orthorombic paraelectric phase. The minimum direct band gap (at the point) is equal to 4.61 eV (for GGA) and 4.34 eV (for LDA).The bands of valency complex are marked relatively weak dispersion in k-space, while the bands of conductivity own considerable dispersion. On the basis of study of partial payments of separate groups of zones their genesis is certain in distribution of closeness of the states. Basic contribution to the states density in area of -4.6 V is on the d-orbital of Zn. Overhead zones of valency complex formed the 3p-orbitals of chlorine, hybridized from 5s- and 4p-states to rubidium, and also by the 3d-orbitals of zinc. Four lower zones of conductivity in a large measure are formed by the s-orbitals of Rb. Only to the fourth zone of conductivity considerable payment is given by the s-states of Zn, noncommunicative near-by the point of Z of zone of Brilluen, hybridized with the p-states of chlorine.
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Issue 5, Pages: 33-41
The influence of chromium impurity on the luminescence properties of ZnWO4 crystals
L. Kostyk, A. Luchechko, S. Novosad
The luminescence spectra at the optical and X-ray excitations, as well as the curves of thermally stimulated luminescence of ZnWO4 single crystals have been studied in this paper. From literature and obtained results follows that matrix luminescence of ZnWO4 is due to self-trapped excitons and exciton localized on defects. Excitation spectra of ZnWO4:Cr and ZnWO4 single crystals registered at 480 nm show a broad band in UV spectral range and the maximum around 320 nm, which correspond to fundamental absorption edge, respectively. The TSL curves of ZnWO4 and ZnWO4:Cr crystals are represented by a set of peaks in the temperature range 160-300 K. The TSL curve of nominal pure ZnWO4 crystal was decomposed on elementary maxima. The activation energies of elementary peaks were calculated using "method of initial increasing", which suggests independence of initial intensity growing from recombination mechanism. Chromium doped crystals show appearing of additional TSL maximum at about 270 K, which may be related with existence of Cr3+e electron centers.
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Issue 5, Pages: 42-49
Modification of porous silicon surface by copper clusters
I. Olenych
Structural and electrical characteristics of low-dimensional systems based on porous silicon modified by copper particles were investigated. It was established that by "electroexplosion" of conductors it is possible to create island-like spherical copper structures, which range in size from tens of nanometers to several microns. The increase of the porous layer conductivity due to copper cluster modification was detected. It was established that the activation mechanism of charge transfer occurs in porous silicon and related low-dimensional systems in the temperature range of 120-325 K. Corresponding activation energy has been estimated.
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Issue 5, Pages: 50-60
Effect of crystal size [N(CH3)4]2CuCl4 on the phase transition temperature
I. Karpa, S. Sveleba, I. Katerynchuk, I.Kunyo, O. Phitsych
The influence of the [N(CH3)4]2Cul4 crystal thickness da and its volume at the phase transition temperature is investigated. The change of value of the phase transition temperature, parent - incommensurate and incommensurate - commensurate phase is resulting from reducing the size of the crystal. Mechanical stress appear due to mismatch of linear expansion coefficients of the crystal and the substrate. With decreasing sample size of the crystal (d<250*10-6m), these stresses increase and the phase transition temperature incommensurate - commensurate phase shifts in high region. The value of incommensurability wave vector increases and the period of superstructure decreases during reducing of the size of the crystal. When the period of superstructure is equal to the order of thickness of the crystal, then it appears the driving force that leads to upwelling of solitons, and an increase of the activation energy necessary for the emergence of new embryos solitons. Under these conditions, narrowing temperature range of existence of IC phase until its disappearance on the phase V, T-diagram is observed.
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Issue 5, Pages: 61-72
Self-trapped hole in the crystal BaCl2
Z. Chorniy, I. Pirko, N. Diyachuk, N. Kobrunovitch, M. Panasiuk, V. Salapak
Investigated the radiative processes in crystals BaCl2, BaCl2-K i BaCl2-Pb2+. It is shown that at T<130K in irradiated crystals are generated (VK-FA) and (VK-Pb+), and at T>130 K (VKD-F) i (VKA-Pb+)-complementary pairs of color centers. Found that VK, VKD and VKA-centers absorb light in the 400, 383 and 380 nm, respectively. Investigated and theoretically calculated azimuthal dependence of the optical density in the absorption bands of hole centers. It is proved that VK-centers in crystals BaCl2 have a structure ion.
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Issue 5, Pages: 73-77
Investigation influence spread current on result of measuring cross-section area liquid stream with the help of conductive sensor
V. Voytuk, D. Trushakov
The work contains the results of theoretical research influence spread current on result current of conductive sensor which used as measuring cross-section area milk stream with the help of conductive sensor. There has been represented a coefficient influence spread current on result of measuring in compare with current value the same sensor without taking spread current. Research influence distance of sensor electrode on which spread current appreciably influence on output current of conductive sensor. Obtained influence of the distance from the sensor electrode, in which current spreading is carried substantial influence on the output value of the current sensor.
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Issue 5, Pages: 78-82
Probe device for measuring of electrophysics descriptions of semiconductor structures
B. Pavlyk, R. Didyk, J. Shykoryak, R. Lys, D. Slobodzyan, A. Hrypa, . Kushlyk
Dislocations, impurities and other defects of the lattice may differently affect the electrophysical properties of semiconductor single crystal. The research of semiconductor materials (such as measuring the distribution concentration profile of electrically active centers and determine the main parameters of deep levels in semiconductor structures by measuring the p-n-junction capacitance) to carry out on samples with different defects concentration. There is a problem to output signals from the generator to the metallic contacts specifically applied in specific areas on the semiconductor surface. To increase the measuring accuracy the diameter of applied contacts must not exceed 0.5 mm. The authors have designed and produced a special device that provides penetration of probes on the contacts. This allows to obtain measurement information from multiple contacts in one cycle of external factors changes. The structure and principle of the device is described.
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Issue 5, Pages: 83-94
Modeling of quadrocopter flight with the peculiarities of sensors
B. Blahitko, Yu. Mochulsky
The results of studies of mathematical models quadrocopter flight with the peculiarities of sensors: altimeter, 3-axis gyroscope, 3-axis accelerometer, 3-axis magnetometer. The mathematical model presented quadrocopter system differential equations in the form of Cauchy 16th order. Input information is the value of quadrocopter altitude, meaning angles pitch, roll, yaw and change them at the time. The way proportional and differential control to stabilize quadrocopter flight and optimal output quadrocopter in preset mode. PD-controller changes the gain traction motors, four screws sign increments and the times in which should be all of these changes. Manageability quadrocopter flight tested for example automatic execution of simple aerobatics figures - a horizontal figure eight - both right and left-turns.
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Issue 5, Pages: 95-101
Multi-state PAL models for inner free-volume study of sensor ceramics for solid-state electronics
H. Klym, O. Shpotyuk, I. Karbovnyk, R. Kochan
The positron annihilation lifetime models for describing of positron and positronium trapping in inner free-volume structure of solids for example of spinel ceramics are analyzed. It is shown that in fine-grained poorly-nanoporous NiMn2O4-CuMn2O4-MnCo2O4 ceramics there is one defect-related positron annihilation channel. In the case of high-porous MgO-Al2O3 ceramics two independent channels of positron annihilation should be considered - the positron trapping and orthopositronium decaying combined with a so-called "pick-off" annihilation process in nanopores usually filled by water.
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Issue 5, Pages: 102-113
Prediction environmental parameters based on artificial neural networks
O. Dzendzelyuk, Z. Lyubun, V. Rabyk
The general algorithm for time series prediction based on artificial neural networks is considered. This algorithm consists of the following stages: the process of the incoming data, computation of the number of neurons in the hidden layer, the construction of artificial neural network for the forecasting of weather information. For training of multilayer neural network the algorithm of back propagation error ("backprop", "rprop +", "rprop-") is used. As an example, the artificial neural network for short-term forecasting of environmental parameters (temperature and pressure in Chornogirskyy geographical station of Lviv National Ivan Franko University) is implemented using the R programming language and the package "neuralnet".
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Issue 5, Pages: 114-125
The problems and modelling of active mediums interoperability in the Earth’s crust and mantle
V. Fourman
The model has been developed and analytical solutions of identifying deformations in the active areas crust and the mantle of the Earth were found, deformations which were created by natural effective anomalous densityin the gravitational field of the Earth. On the basis of numerous modelling of the developed convection in conditions of a mantle of the Earth there is a possibility to investigate an interoper-ability of mantle convection with lithosphere and to restore the distribution of temperature in the top part of lithosphere.
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Issue 5, Pages: 126-131
Optical-geometric analysis dielectric waveguides
T. Polovynko, G. Grynchuk, I. Polovynko
In this paper, under a frame of geometrical optic description of dielectric waveguides, analysis of cross resonance for different transparent media is considered. The expression for calculating angles spread waveguide modes was programmed. Calculations performed for symmetric waveguide with a single GaAs material, in which where realized such properties of optical planar elements as generation of the laser radiation, spread it through the waveguide, modulation, detection, and others. The calculations confirmed that for zero optical mode cut-off conditions is not exist, that will apply to the arbitrarily small thickness. Besides the refractive indices, the program takes into account the thickness of the waveguide, the order of modes and the wavelength of the optical radiation. The program was written in the programming environment Embarcadero. By using the obtained results such important parameters as the waveguide effective refractive index waveguide normalized frequency, normalized film thickness and rationed refractive index where calculated. The data are important for solving the problem of converting the laser beam into the surface wave and vice versa, i. e. the conversion optical wave in the output beam. Written program also allows you to calculate the angle of total reflection for TE-wave of various ranks of optical modes.
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Issue 5, Pages: 132-136
Simulation of conservative systems by traditional numerical methods
Ya. Kost, J. Khvyshchun, Ya. Shmygelsky
The work reports the results of numerical experiments on modelling of nonlinear conservative systems using traditional numerical integration methods. Nonlinear systems with known first integrals were selected as test cases. All tested methods were evaluated by the deviation between the exact and the calculated values of the first integral over significantly long time intervals. The results of the experiments allow to provide practical recommendations for researchers regarding the selection of the numerical integration technique for the simulation of conservative systems.
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Issue 5, Pages: 137-150
Basic concepts and solving the computerized game theory
A. Ivashchenko
Solving of the theory of games problems with practically acceptable time is only possible with a computer using appropriately selected or specially designed programs. Thus describes the main concepts and features of the solution of problems of the theory of games. It is noted that using of information and communication technologies make the process of solving the theory of games easy and interesting, and will void the user from routine and time-consuming calculations. The analysis the software tools for solving tasks of the theory of games.
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Issue 5, Pages: 151-158
Microprocessor system monitoring environmental parameters based on microcomputer Raspberry Pi
Yu. Badziuk, A. Batiuk, M. Batiuk, V. Dzikovskyi, V. V. Rabyk
The hardware and software of the Raspberry Pi based microcomputer system for environmental parameters monitoring are described. Principal technical parameters of the microcomputer and GPIO signals are discussed in details. System sensors specifications (digital temperature sensor, digital humidity sensor and analog pressure sensor), environmental parameters that can be measured, transmitted and stored on SD Card are discussed. Modes of operation of the microprocessor system, its functional diagram and the purpose of all components are explained in details. The software of the measurement subsystem, algorithm of measured data transmission via GSM modem and data file structure are described. Program interface created using C++ in Qt Creator for Weather_Database software used for work with the database is discussed. An example graph illustrating temperature air change in 2015 in Lviv is presented.
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Issue 5, Pages: 159-166
Comparative analysis of tools for crossplatform programming
G. Zlobin, O. Chmykhalo
The article provides a comparative analysis of crossplatform programming tools. Crossplatform programming tools are divided into three groups: crossplatform compiled languages (Table 1), crossplatform programming languages at the execution level (Table 2) and crossplatform interpreters (Table 3). The information in Tables 1-3 ordered by number of the supported operating systems (descending). Table 4 provides information about standardized libraries and frameworks used in crossplatform programming. To substantiate the results of the analysis the index of popularity of programming languages TIOBE is used.
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Issue 5, Pages: 167-174
Rank dependences and lexical frequency spectra for the subgroups of different-length words in texts
O. S. Kushnir, M. Ya. Maksysko, L. B. Ivanitskyi, S. V. Rykhlyuk
In this work we have found statistical word-length distribution for the text of J. R. R. Tolkien’s novel "The Lord of the Rings". We have studied ’partial’ dependences rank-frequency f(r) and probability density functions p(f) for the subgroups of words with different lengths (l = 1-16 letters), as well as the corresponding ’combined’ dependences for the words of all lengths. It has been revealed that the "partial" dependences are in general worse described by the power laws, known as Zipf’s ones, than the ’combined’ ones. The functions f(r) and p(f) for the intermediate lengths l = 5-10 are the closest to the power law, with the exponents α≈1 for f(r) and β≈2 for p(f). The hypothesis has been put forward that the rank dependences for the smallest lengths can turn out to be close to exponential (α→∞), similar to the f(r) function for some Eastern languages with a limited vocabulary, while the rank dependence and the probability density for the largest l can tend respectively to logarithmic (α→0) and exponential (β→∞) functions.
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Issue 5, Pages: 175-184
Image upsampling with randomized interpolation
V. Parubochyi, R. Shuwar, D. Afanassyev
A new method for upsampling of bitmap images based on randomized interpolation is described. A problem of aliasing, visibility of digital artifacts and accuracy of image analysis is discussed from the viewpoint of the nature of quantization error. A possibility of obtaining a noise-like residual error and attenuation of regular artifacts by the method proposed is demonstrated.
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Issue 5, Pages: 185-191
Parallel methods for solving linear algebraic equations using CUDA
A.Khariv, I.Khvyshchyn
Mathematical modeling problems from a formal point of view is not a problem because the differential, integral or non-linear systems are often reduced to solving systems of linear algebraic equations that can be solved by Gauss or its modifications. However, when solving systems of linear algebraic equations high order methods for computational complexity is rather high and, along with this is the need to solve these systems in real time.
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Issue 5, Pages: 192-199
Intersubject links when training computerized of translation professional of texts
N. Franchuk
Information and communication technologies are widely used in various fields of human activity. Vision interdisciplinary connections encourages the development of creativity and logical thinking, ability to analyze facts creates different fields of knowledge and to find rational ways of solving various problems, install new study properties of objects. The creation of intersubject courses leads to a system that integrates competencies from different disciplines. In the study course "computerized translation of professional of the texts" combined knowledge, skills and abilities that are formed in the process of training as informatics disciplines, and in the process of learning a foreign language. During the training this discipline implemented intersubject links informatics and mathematical sciences and foreign languages.
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