1. The finite difference scheme in time domain (FDTD) and analytical solution to Klein-Gordon equation
Yu Zheng, B. A. Kochetov, A.Yu Butrym
Klein-Gordon equation, FDTD, finite difference equation, Laguerre impulse
Vestnik KhNU ¹712 Pages. 91-94
A finite difference algorithm for solving inhomogeneous Kleine-Gordon equation in Time Domain with arbitrary waveform pointwise source is considered in the paper. The numerical results were compared with analytical so-lution that was obtained using Laplace transformation in a convolution operator form. The results confirm validity of both the obtained numerical algorithm and the analytical solution
2. Electromagnetic wave detraction on a resistive unclosed cone
V.A. Doroshenko, O.G. Litvinova
diffraction, resistive, Longitudinal slots, an integral transform, analytical solutions
Vestnik KhNU ¹712 Pages. 95-99
Problem of harmonic electromagnetic wave diffraction on a resistive cone with longitudinal slots is considered. The boundary problem solution uses the Kontorovich-Lebedev integral transform and a semi-inversion method. Analytical solutions are obtained for the cone with a lot of narrow slots and reactive impedance. Impedance and longitudinal slots effects on scattering field structure is studied
3. EXCITATION OF AN UNCLOSED CONE PLACED AT AN IMPEDANCE PLANE
V.A. Doroshenko, O.G. Litvinova, A.V. Sova
excitation, an impedance plane, cone, Longitudinal slots, analytical solutions
Vestnik KhNU ¹756 Pages. 42-46
By using the approach that is based on applying the Kontorovich-lebedev integral transforms method and a semi-inversion method an excitation boundary problem for a cone with periodical longitudinal slots provided that cone placed at an impedance plane is investigated. It is showed that the problem under consideration is equivalent to solving a system of linear algebraic equations for Fourier coefficients of electromagnetic field components. Analytical solutions are obtained for a semi- transparent cone and special plane impedance. Impedance plane effects are studied
4. INFLUENCE of ENVIRONMENT ON the FIELD, SCATTERING ON the LATTICE WITH LAYER, AT ANY FALL of the WAVE
A.I. Adonina, V.B. Khokh
Lattice, environment, dielectric, a stream of capacity, method of Riman-Hilbert problem
Vestnik KhNU ¹756 Pages. 51-56
The decision of a task in view is carried out for Å and Í the fields appropriate to two subsystems on which the system of the equations of the Maxwell for environments is divided. Integrated characteristics of a field are determined from the decision of systems of the linear algebraic equations received by a method of method of Riman-Hilbert problem , for a case when the smallest parameter decreases in inverse proportion to a square n->infinity. Programs (fort) with construction of diagrams are made. The analysis of the diagrams in part given in work, allows to establish influence of parameters of structure and corners of fall of a wave on anomalies in an absent-minded field for each concrete case
5. SPECKLE – INTERFEROMETRICIAN METHOD FOR ANEMOMETRICIAN OF TURBULENT STREAMS
G.N. Dolya, À.N. Katunin, Ê.V. Sadovy, S.I. Shmatkov
, speckle – interferometrician, anemometrician, speckle – painting, Light-reflecting coverage
Vestnik KhNU ¹756 Pages. 118-122
In this paper is researched the possibility of the use of the modified speckle – interferometrician method for anemometrician of turbulent streams. It is developed laser anemometer on the basis of the modified speckle – interferometrician method at the applications of light-reflecting coverage. Is dependence of increase of border frequency of signal’s spectrum at growth of speed of stream transversal to the ray. Dependence of spectrum of fluctuations the adopted signal on the degree of the brought distortions in at a different temperature of turbulent stream is explored
6. CALCULATION and EXPERIMENTAL MEASUREMENT OF ANODE BLOCKS PARAMETERS OF MAGNETRONS
K.M. Basrawi, G.I. Churyumov
magnetron, anode block, Q quality factor, Loaded Q factor, equivalent capacity, mode
Vestnik KhNU ¹756 Pages. 132-138
In this paper the outcomes of calculation and experimental measurements of cold parameters of the pulse and continuous X - range magnetrons are presented. The measuring and calculation techniques of equivalent capacities of the anode blocks of the magnetrons as well as Q quality factor, loaded Q factor and external Q factors of the resonant system for main N/2 - mode and nearest N/2 -1 and N/2 -2 -modes is given
7. HARMONIC GENERATION BY IMPACT IONIZATION IN CaN LSA DIOD
O.V. Botsula, D.V. Pavlenko, E.D. Prokhorov
LSA diodes, generation efficiency, nitrides, drift velocity, harmonics
Vestnik KhNU ¹806 Pages. 65-69
In this work an impact ionization in LSA diodes on basis of GaN is considered. Analytical calculation of typical times of passing of a number of the physical processes determining properties of the oscillator, and limitings imposed by them on frequency properties of the diode is submitted. It is shown, that at developing impact ionization in LSA diodes, according to the diffusive theory, the considered compounds are perspective for manufacturing LSA diodes for work in sm and mm - ranges (electrical pressure over threshold 3 … 5 times, at an efficiency up to 11 … 13 %). The results of calculation of efficiency of oscillators on basis of GaN LSA diodes are given at their work in modes on a base frequency and at a harmonic generation.
8. Identification and localization of radar impulses buried in noise
A. G. Tyzhnenko, Y. V. Ryeznik
radar, pulse, identification, Localization, Low SNR
Vestnik KhNU ¹806 Pages. 70-74
Statistical method identification and localization of radar impulses buried in noise is addressed. To this end, the correlation coefficient between carrier samples measured in the extremal points and analogous set of points of received signal is proposed to implement. Such measurements for receiving signal need to be done at least by one tenth of the half period of the carrier. Because of very simple algorithm proposed, such measurements do not lead to heavy computational burden. To decrease identification and localization errors for given signal to noise ratio (SNR) one needs to increase the number of measurements points, and hence, the pulse width. To prevent this issue, one can increase the carrier frequency. In general, the method accuracy increases with the carrier frequency. The method proposed permits theoretically to identify with fidelity impulses buried in noise for SNR lower than -30 dB.
9. QUEST AND CREATION OF NOVEL ACTIVE MEDIA FOR DYE LASERS IN IRE NAS OF UKRAINE
Laser dye, molecular structure, spectrum, fluorescence, quantum yield, Lasing efficiency, photostability
Vestnik KhNU ¹806 Pages. 92-98
Numerous studies of novel active media for dye lasers fulfilled in IRE NAS of Ukraine are generalized in present review. Peculiarities of spectral, fluorescence and lasing characteristics of some laser dye classes for visible region of the spectrum have been analysed. A special attention is focused upon effects of structure of the dye molecule and its solvent environment on these characteristics. The outlook of development for dye-doped active media has been discussed
10. Fields of the rectangular loop antanna in near-field zone
N.N. Gorobets, À.V. Trivaylo
electromagnetic waves, radiation, near-field zone, Hertz vector, traveling wave antenna, Loop antenna
Vestnik KhNU ¹834 Pages. 18-24
On the basis of potential Hertz technique the expressions for calculating of all components of electromagnetic radiation fields of rectangular loop antenna, stimulated by the running wave of the current in Spherical and Cartesian coordinate systems unrestricted on the size of radiator and distance up to a point of observation have been derived. It has been shown that in a near field zone of radiation electromagnetic vectors in the Cartesian and Spherical coordinate systems have all 6 component. It has been shown that wave processes near by the examined radiators are distinguished by great gradients of amplitudes of the electromagnetic fields
11. Potential of a spherical segment which is placed within a spherical layer with circular aperture.
electrostatics, spherical segment, Layer, Fredholm integral equation
Vestnik KhNU ¹834 Pages. 120-126
The rigorous solution of an axially symmetrical electrostatics problem is obtained. The potential of an ideal spherical segment, which is placed within a spherical layer with circular aperture, is analyzed. We use the methods of regularization, separation and inversion of summarized equations, the method of residues in singular points of analytical functions, the methods of contour integrals and integral transformations. Fredholm integral equation of the second kind with a compact operator in Hilbert space L2 is obtained. The comparison with known results and limit variants is given. The effectiveness of the constructed algorithm is confirmed. Some generalizations of the problems are considered
12. Inner partial mutual admittance of two overlopping longitudinal slots in a rectangular waveguide with dielectric layer parallel to narrow walls
A.A.Lyakhovsky, L.P.Yatsuk, A.F.Lyakhovsky
, Layer, dielectric, slot, admittance, scattering parameters
Vestnik KhNU ¹853 Pages. 22-27
The expression for the partial inner mutual admittance of two longitudinal slots overlapping along waveguide longitudinal axis is obtained. The slots are cut in a broad wall of a rectangular waveguide filled with three-layered dielectric. The excitation problem is solved with the modified eigen waves method. As eigen waves of the LE and LM modes are chosen. The field in the source region includes the potential functions as well. Dependences of inner mutual admittance and scattering parameters on distance between two slots and frequency are investigated. The system scattering parameters calculated are in a good agreement with experimental data
13. Single cone with longitudinal slots excitation by an impulse point source
A.V. Artyukh, y.A. Doroshenko, Y.D. Shimuk
impulse source, cone, Longitudinal slots, analytical solution, numerical solution
Vestnik KhNU ¹853 Pages. 51-56
In this work the excitation of a semi-infinite perfectly conducting cone with periodic longitudinal slots by an impulse radial source problem is investigated. The solution of the well-posed initial-boundary problem is found using an analytically numerical method based upon Green function and Meler-Fock integral transforms applying. It is shown that the original electrodynamic problem is equivalent to the one of the Fredholm linear algebraic equations system of the second kind solving. Analytical view of the solution is derived and the graphs illustrating the field dependence on the aperture angle and angle slot width are presented
14. Random inhomogeneous liquid medium as a continuous laser of low-intensity modulator for excitating sound in the medium
B. G. Yemets
Laser, random inhomogeneous liquid medium, interference, temperature field, optical acoustical phenomenon, sound, excitation, modulation
Vestnik KhNU ¹853 Pages. 95-100
When a medium is irradiated by laser pulses, sound waves are excited in this medium, i.e., the well-known optical acoustical phenomenon occurs. To excite sound oscillations, the specific laser beam modulator is shown to be unnecessary. The role of the modulator can play the liquid itself, which is a random inhomogeneous medium. The real liquid contains suspended solids and gas bubbles of small dimensions (dust particles and the like) that move irregularly in space (fluctuations). As a result, the electromagnetic wave interference taking place in the liquid undergoes random changes. Consequently, the temperature field changes, and hence variations in the local pressure occurs (thermo-optical mechanism for exciting sound). The excitation of sound due to the laser irradiation of low intensity is observed in an increase in the gas bubbles dimensions in the liquid
15. Analysis of impulse fields reflected from layered medium with losses using artificial neural network
Shyrokorad D. V., Dumin O.M., Dumina O.O., Katrich V.O.
time domain, artificial neural network, impulse fields, Layered medium
Vestnik KhNU ¹883 Pages. 35-40
The problem of determination of thickness a layer of layered medium by impulse irradiation is solved. The impulse fields reflected from the layered medium with electrical characteristics close to the characteristics of human skin are analyzed by artificia
16. NonstationarY processes in the hybrid O-type beam-wave system
Odarenko E.N., Shmatko A.A.
nonautonomous oscillatory system, Locking, beats
Vestnik KhNU ¹966 Pages. 23-30
Nonstationary processes in the resonant beam-wave system with pre-modulated electron beam are investigated in this work. Theoretical analysis is performed on the basis of the nonlinear multidimensional theory of the hybrid O-type electron devices. Basic regularities of the external signal power effect on the lock range width are described. Regimes of the oscillations synchronization, beats and squitter for different values of the oscillation system and ex-ternal signal parameters are considered.
17. Optical synthesized apertures in holographic television systems
Holographic television, synthesizing holograms, Linear antennas, CCD-matrices, color holographic television systems
Vestnik KhNU ¹966 Pages. 56-67
The analysis of the modern state of investigations concerning the creation of holographic television has been carried out. The new methods of hologram formation on photo electronic devices are proposed. The scheme of the holographic television system realizing the method of synthesizing optical holograms is presented. The possibility of synthesizing three-dimensional holograms of volume objects on photo electron devices is shown. The method and principles of constructing colour holographic television system is proposed.
time domain, artificial neural network, impulse fields, Layered medium
Vestnik KhNU ¹883 Pages. 35-40
The problem of determination of thickness a layer of layered medium by impulse irradiation is solved. The impulse fields reflected from the layered medium with electrical characteristics close to the characteristics of human skin are analyzed by artificial neural network in time domain directly. The normal incidence of plane wave with Gaussian time form is considered. The reflected electromagnetic field is calculated by FDTD method. Initial data for the neural network analysis are the values of amplitude of electrical component of reflected field. As an example, the network is trained to determine the thickness of one of the layers of the medium. The stability of the determination in presence of interferences, experimental errors and instabilities of medium parameters is investigated.
Layered media, dispersion, inverse problem, dielectric permittivity.
Vestnik KhNU ¹883 Pages. 45-49
In the present paper the problem of dielectric permittivity profile reconstruction with regard to dispersion is discussed. The nature of the dispersion function is assumed to be known and unknown functions are real and imaginary parts of dielectric permittivity. Frequency is used as an informative parameter. It is assumed that the layered medium is laying on a substrate with known dielectric permittivity and permeability. The iterative method reducing the problem of reconstruction to the functional minimization problem is used. Within the scope of this method the inverse problem for of dielectric permittivity profile with a conducting medium dispersion is solved. The algorithm and numerical results are given.
20. The xecl laser with the adjustable shape and duration of generation pulse
S.S. Anufrik, A.P. Volodenkov, K.F. Znosko
LC- contour, XeCl laser, excitation system, generation energy, pulse duration.
Vestnik KhNU ¹983 Pages. 3-10
The generation parameters of LC-contour excitation system are studied for electro-discharge excimer XeCl laser using a Ne–Xe–HCl mixture. A computation model is developed for finding the generation parameters. It has allowed us to calculate current, voltage and generation power oscillograms for all parameters of the electrical excitation system. The program of XeCl-laser modeling enables to calculate an electrons, atom and molecule concentrations, specific energy deposition in active medium also. By means of program Bolsig + calculation of rate coefficients of reactions with participation of electrons is executed. It is shown that generation of short radiation pulses (20 ns) and relatively long pulses (60 ns) is possible due to changing of LC- contour parameters. Energy of generation reaches a maximum at use of small values of peaking capacity, which are significantly smaller then value of storage capacity.
Laser radiation, acoustic emission, plasma, crater, a zone of non-elastic destruction, Laser-plasma evolution.
Vestnik KhNU ¹983 Pages. 11-17
Acoustic emission of a zone of the destruction formed during influence of pulse laser radiation on a surface of metal is considered. Dependence of the time form of acoustic fluctuations on parameters of an irradiated material and the law of increase in depth of a crater was estimated. It is revealed, that at action on a surface of the copper sample of a laser impulse duration 20 ms time of growth of a zone of destruction makes approximately 40 ?ñ, that will well be coordinated with time of existence of plasma formation at a surface of the target exposed to laser-plasma processing (50 ms).
optical element of the cylindrical form, Light scattering, Monte-Carlo method, indicatrix of scattering, index of refraction
Vestnik KhNU ¹983 Pages. 67-71
Modeling of characteristics of optical spectral-selective elements of the cylindrical form with the increased value of the refraction index, using effect of light scattering is organized. The parameters of the optical element materials, forming its spectral-selective characteristic are determined. As have shown results of researches, application of cylindrical optical element for spectral angular selection is possible in limited range of values of the index of refraction. At increase in value of refraction index before determined level the optical element starts to function in a mode of quasi uniform light scattering.
wave equation, exact solutions, Localized waves, Bateman solution, general astigmatism.
Vestnik KhNU ¹983 Pages. 77-83
A new class of exact non-harmonic in time solutions of 3D wave equation is established. This class is a generalization of the known complexified relatively undistorted Bateman-type solution, involving an arbitrary function, waveform. Argument of this function is much similar to that which appears in general astigmatic paraxial Gaussian beam. Special choices of the waveform allow general astigmatic beam-like and packetlike waves with Gaussian-type localization in space and time.
GaAs diodes, drift speed, Lag, coefficient frequency conversion, maximum frequencies.
Vestnik KhNU ¹927 Pages. 11-14
Coefficient frequency conversion (KFC) diodes with intervalley transfer of electrons based on GaAs in a wide range of frequencies is investigated. It is shown that the threshold voltages of the KFC in mobility 8000 sm2/(V·s) (GaAs) more than the KFC in 1000 sm2/(V·s) mobility (without NDC) in 5 times. At the further increase voltages in the mobility ratio of KFC 8000 sm2/(V·s) to KFC for 1000 sm2/(V·s) mobility decreases (at 10 - 12 kV/cm is about 2, at 20 - 30 kV/cm ratio KFC close to unity). Take into account the inertia of the redistribution of electrons between the valleys of the conduction band of GaAs. It is shown that the transformation frequency conductivity GaAs diodes is possible at frequencies exceeding the maximum frequency of generation in the diode mode of a uniform field.
Laser, optical radiation, intensity, distribution, receiver, direct problem, inverse problem.
Vestnik KhNU ¹927 Pages. 31-35
In this paper has been considered the method of the measurement of the intensity distribution in the beam of optical radiation and the algorithm of processing of a signal from the receiver. The method is using the knife attenuator of the special shape. The power of the reflected radiation on knife was measured by using detector of photoelectric. The algorithm and program for handling of the signal from receiver are developed. The influence of errors in the measurement signal from the receiver on the results of calculations has been researched. The experiment has confirmed the serviceability of the method and the possible of their use in practice.
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