1. Integral representation of green function in parallel-plate and rectangular waveguide, and in resonator as well
V.A. Katrich, F.S. Novokhatsky
waveguides, Green function, fundamental solution, radial function, elliptical teta- function, image method, calculus of residues, integral transformation, Grating, formal variative
Vestnik KhNU ¹712 Pages. 67-70
The known results connected with Green function representation by elliptical theta-function are generalized. New representations of Green function for some widely used types of waveguides are obtained. Earlier, these Green functions are presented either in form of series with nonuniform convergence or in form of integrals containing Hancel functions, which are reduced to asymptotic expressions in far zone. On this work integral representations of Green functions are obtained for Cases where the quadrature formula exists. The method of analytical continuation with parameter is applied
2. GaAs-Gunn diodes with small levels of power constitution for mm-range oscillators
E.D. Prokhorov, A.V. Dyadchenko, N.E. Polyansky
Gunn diodes, microwave powers, efficiency, Generators mm-range
Vestnik KhNU ¹712 Pages. 115-118
Experimentally investigated small level operating power GaAs generators mm-range. Samples of diodes made in Problem laboratory of semiconductor engineering of the Karazin Kharkov National University. GaAs -Gunn diodes oscillators operated in continuous mode. The obtained experimentally operated powers made 10...30 mW, the useful microwave powers - 0,1...0,3 mW at an efficiency of 1...2 % over the range frequencies of 60...75 GHz. Probably further reduction consumed by diodes and oscillators of power up to hundreds and tens 10-3W
3. The spectrum of current oscillations of Gunn diodes with the impact ionization in moving domains
D.V. Pavlenko, E.D. Prokhorov
Gunn diode, impact ionization, UHF-noise
Vestnik KhNU ¹712 Pages. 123-126
The results of the numerical simulation of the GaAs Gunn diode with electric field strengths, enough for development of the impact ionization in the moving high-field domains, are presented. The form of current oscillations and frequency spectrums is in good agreement with experimentally measured data. It is shown that the Gunn diode, operating under conditions of the impact ionization, may be used as a source of wide spectrum UHF-noise
4. The Gaussian beam scattering on the bounded sequence of alternate grates of dielectric bars
V.B. Kazanskiy, V.R. Tuz, D.V. Yudintsev
Gaussian beam, thick grate of dielectric bars, anisotropic layer, periodic structure
Vestnik KhNU ¹756 Pages. 83-86
The Gaussian beam scattering on bounded periodical sequence of thick grates of dielectric bars are investigated. Identification of discrete structure with appropriate thickness homogeneous anisotropic layer was carried out for define sequence basic element transmission matrix. The sequence scattering coefficients were written down via Mougin polynomials. The effects of form distortion, beam splitting into several beams, side shift of beam axe were shown. Their correlation with scattering coefficients phase and module angle dependence of separate grates was established.
5. On the primary mechanism for microwave therapeutic effects arising during gamma ray pathology
B. G. Yemets
electromagnetic microwaves, Gamma rays, air bubbles, biologically active points
Vestnik KhNU ¹756 Pages. 139-143
The biologically active points (BAP) show an increase in size due to an increase in size of air bubbles at near-membrane water layer in the biologically active point cells. The increase in the air bubble size is produced by sweeping the microwave frequency.
6. Arbitrary falling of wave on grate with by ànisotropic layer
A.I.Adonina, R.R.Naumov, A.I.Sljusarev
Grate, magnetodielectric, stream of power, method of Riman-Gilbert, anisotropic, resonator
Vestnik KhNU ¹806 Pages. 22-28
A decision set the problem is conducted for Å and Í pour, proper two subsystems into which the system of equalizations of Maxwell is divided for anisotropic environments. The mixed field (in the case of the arbitrary falling of wave) is determined as a sum of two types pour. Integral descriptions are from the decision of the reduced endless systems of linear algebraic equalizations, got the method of task of Riman-Gilbert. The analysis of the graphs, partly resulted in work, allows to set influencing of parameters of structure and angles of incidence of wave on an anomaly in the dissipated field for every concrete case, and also to suppose and to confirm physical reasons of existence of anomalies a numeral account, as resonances of own waves in the opened resonator which is design the explored structure.
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. Near electromagnetic field of combined waveguide-slot radiators in matter
S.L. Berdnik, V.A. Katrich, M.V. Nesterenko, S.V. Pshenichnaya
rectangular waveguide, waveguide-slot radiator, material medium, hyperthermia, Galerkin's method
Vestnik KhNU ¹834 Pages. 85-88
The problem about the electromagnetic waves radiation into the homogeneous isotropic medium by the system of combined waveguide-slot radiators in the broad wall of a rectangular waveguide has been solved in a rigorous self-consistent formulation. The spatial distribution of the near field intensity in the half-infinite material medium with the electrophysical parameters, corresponding to some man's tissues, has been investigated
9. Capacitance-voltage measurements in selectively doped ALGAAS/GAAS heterostructures
N.B.Gorev, I.F. Kodzhespirova, E.N. Privalov
Gallium arsenide, selectively doped heterostructures, Schottky barrier, barrier capacitance, capacitance–voltage measurements
Vestnik KhNU ¹853 Pages. 3-7
The dependence of the measured apparent capacitance of selectively doped AlGaAs/GaAs heterostructures on the amplitude of the measuring ac voltage is calculated numerically. An expression that gives the measured apparent capacitance as a function of the true capacitance and the above amplitude is derived. Using this expression and the results of the above numerical calculation, it is shown that capacitance–voltage characteristics of selectively doped AlGaAs/GaAs heterostructures, which feature steeply dropping regions, may be measured at moderately small amplitudes of the measuring ac voltage (of the order of 100 mV) at the expense of taking measurements at two different amplitudes
10. Global Sensitivity analysis of the dipole matrix element according to variation of parameters of the indium surface segregation in ingan/gan quantum well
indium surface segregation, semiconductor nitrides, piezoelectric polarization, dipole matrix element, Global sensitivity analysis
Vestnik KhNU ¹853 Pages. 8-14
In this paper, influence of the indium surface segregation on dipole matrix element for InGaN/GaN heterostructure is under investigation. The global sensitivity analysis has been applied for quantitative estimation of the indium surface segregation effect at each interface of the quantum well. Together with the indium surface segregation, the piezoelectric effects are considered. It has been shown that joint action of the piezoelectric fields and the indium surface segregation leads to changes in the selection rules for optical transitions. Results give the method to apply the optical spectroscopy for observation of the indium surface segregation
11. Oscillation efficiency of TED diodes on the basis of nitrides
E. D. Prokhorov, O. V. Botsula, A. N. Zabazhan
AlN, GaN, InN-diodes, drift speed, oscillation efficiency
Vestnik KhNU ¹853 Pages. 15-21
Oscillation efficiency of intervalley transfer electrons diodes on the basis of nitrides (InN, GaN, AlN) is considered. Electric fields at peak oscillation efficiency are determined. The results have been compared to results for GaAs. The account of floatable potential in connections InGaN improves their power characteristics in comparison with power characteristics of these connections without taking into account floatable potential, maximal efficiency In0.8 Ga 0.2 sub>N and In0.5Ga0.5N diodes to compare to InN diodes on 30 % is higher (22 % to compare to 16,43 %) but at more high tensions of an electric field. The maximal oscillation efficiency is observed at higher electric fields than GaAs ( from 250 êV/sm for InN to 1000 kV/sm for AlN)
12. Arbitrary falling of wave on grate with by a screen and layer of environment
A.I.Adonina, R.R. Naumov, A.I.Sljusarev
Grate, magnetodielectric, stream of power, method of Riman-Gilbert, resonator
Vestnik KhNU ¹853 Pages. 45-50
A decision of the set problem is conducted in the exact raising without imposition of limits on the parameters of structure, angles of incidence of wave, wave-length, parameters of environment. The variant of method of Riman-Gilbert was used for the case of the arbitrary falling of wave. A vectorial task is presented as a sum of two scalar tasks, proper subsystems into which the system of equalizations of Maxwell is divided for Å- and Í-fields. A numeral account, resulted in work as the graphs, confirms assumption about physical reasons of existence of anomalies, as resonances between active spectral accordions and own waves of the opened resonator which designs the explored structure
13. FREQUENCY MULTIPLICATION AT IMPUCT IONIZATION IN TRASFER ELECTRON DIODES ON BASIS AlN, InN
E. D. Prokhorov, O.V. Botsula, I. A. Grishchenko
AlN, GaN, InN diodes, frequency transformation factor , drift velocity, harmonics.
Vestnik KhNU ¹883 Pages. 30-34
Multiplication of frequency at impact ionization in intervalley transfer electron diodes on basis InN, AlN is considered. The current – voltage characteristics of intervalley transfer electron diodes have negative conductivity region and strong increasing
14. Determination of optimal parameters of a magnetocardiographic hexagonal measuring grid
A.Yu. Kostiev, A.Yu. Butrym, S.N. Shulga
magnetocardiography, Gradiometer, current dipole, sensitivity, Hessian
Vestnik KhNU ¹883 Pages. 25-29
The article considers hexagonal grid of gradiometer sensors of magnetic field. The aim of the study is to determine the optimal parameters of the grid and the gradiometers in order to obtain maximum sensitivity of the measuring system in terms of location
15. The accumulation of gas in galactic objects
Sorokin A.A., Sorokin A.F., Zaharova M., Sokolova O.V., Gorobets N.N.
astrophysics, Galactic objects, the accumulation of gas
Vestnik KhNU ¹883 Pages. 3-7
The mechanism of the accumulation of gas in the galactic objects submerged in the large-scale magnetic field is examined. As a consequence of the diamagnetism of the plasma subsystem of object, the stopper geometry of magnetic field with the radial electr
16. The geometrical approaches to the calculation of propagation of Gaussian beams in hollow metal waveguides in the terahertz range
Gurin O.V., Degtyarev A.V., Maslov V.A., Svich V.A., Senyuta V.S., Topkov A.N.
metal waveguide, Gaussian beam, terahertz range, Geometrooptical approach, transmission coefficient
Vestnik KhNU ¹966 Pages. 3-8
A comparison of the results of calculations of the transmision for Gaussian beams in hollow circular metal waveguide using geometrooptical procedures by Frost and Crenn with the results of experiments in the
terahertz range is performed. The conditions of applicability of these methods to study the transmission characteristics of metallic waveguides of different lengths were found. It is shown that in this range the geometrooptical approach, proposed by Frost, provides satisfactory results only for short waveguides, the length of which corresponds to the condition of the near zone. The geometrooptical approach by Crenn is applicable to both short and for long waveguides.
astrophysics, Galactic objects, the accumulation of gas
Vestnik KhNU ¹883 Pages. 3-7
The mechanism of the accumulation of gas in the galactic objects submerged in the large-scale magnetic field is examined. As a consequence of the diamagnetism of the plasma subsystem of object, the stopper geometry of magnetic field with the radial electric field is formed. In this configuration, effective retention and the accumulation of the plasma, which revolves in the lattice-type fields, occurs. Atoms are tightly connected on the effects of recharge with the ions, which provides their accumulation. The calculated distributions of molecular and atomic hydrogen in our Galaxy, whose the stopper geometry of its magnetic field is well-known, are given. It is shown that this mechanism describes well the basic special features of gas subsystems
AlN, GaN, InN diodes, frequency transformation factor , drift velocity, harmonics.
Vestnik KhNU ¹883 Pages. 30-34
Multiplication of frequency at impact ionization in intervalley transfer electron diodes on basis InN, AlN is considered. The current – voltage characteristics of intervalley transfer electron diodes have negative conductivity region and strong increasing current regions due to impact ionization that is nonlinearity and lead to transparent frequency. If impact ionization takes place, frequency transformation factor increases and reaches, for example, 40 % for second harmonic have being showed. The frequency transformation factor increases for second and third harmonic if first harmonic voltage amplitude is several threshold voltage if compare with frequency transformation factor for all nitride compounds.
19. 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.
20. Impact of random variations of air hole diameters and random variations of the centers position of air holes on operation parameters of a solid core microstructured optical fiber
A.I. Filipenko, A.N. Donskov
finite-element method, Gaussian distribution, inclusions diameter, total mode field power, angular positioning, microstructured optical fiber.
Vestnik KhNU ¹983 Pages. 29-32
We investigated the impact of random variations of air hole diameter and random variations of the centers position of air holes on operation parameters in the case of solid core microstructured optical fiber with a ring of air holes. The found results show that at any of considered defect types mode field will have two pronounced maximums. At practical use an investigated type of the MOF special angular positioning end faces of fibers is necessary. We also have shown that random variations of inclusions diameter can increase total mode field power. In our research we used finite-element method.
Grid, bolometer, intensity distribution, polarization, energy center, beam diameter, Generalized cross-sectional square of the beam.
Vestnik KhNU ¹983 Pages. 72-76
In this paper the grid receiver for measuring laser radiation characteristics has been considered. The receiver contains four grids located perpendicular to the direction of propagation. Wire elements are located at angles 0 , 45?, 90? and 135? to the vertical. One grid contains 8 nickel bolometers with diameter 40 microns, bolometers are located on 7.2 mm from each other. The diameter of the window – 60 mm. Intensity distribution in the space has been measured, therefore, the position of the energy center, the diameter, the generalized cross-sectional square of the radiation beam have been determined. The Radon transformation has been used as the mathematical basis of signal processing algorithms. Also the polarization direction and intensity distribution of polarized radiation have been measured by a numerical experiment.
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.
Gravimeter, superconducting suspension, optical registration, thin films, superconducting ring.
Vestnik KhNU ¹983 Pages. 107-113
This paper considers the problem of designing and developing optical-cryogenic devices using new physical principles, mathematical methods, and new superconducting materials. The sensor element is based on new ñontrolled magnetic levitation phenomenon, high-precision optical registration of mechanical coordinates of levitating body, and the robust signal processing tools. A controlled self-bearing probe dynamics is also analyzed. We have shown how to produce reliable YBCO thin films with controllable surfaces and physical properties and how to integrate them in a ring form into the optical-cryogenic gravimeter so as to reduce its size and render it convenient for future space applications.
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.
Geomagnetic field variations, magnetoconjugate solar terminator
Vestnik KhNU ¹927 Pages. 85-89
This paper analyzes quasi-periodic geomagnetic field variations in 1 – 1000 s period range that connected with the magnetoconjugate solar terminator action in 2002 – 2008. The measurements have been made near Kharkiv city. The processing was made separately for two seasons: summer and winter solstices. Magnetoconjugate solar terminator causes the perturbations relatively the solar terminator moving at the height of 100 km with the lead time 80 – 100 min. Dominant periods were 10 – 12 min and the duration was 50 – 60 min. Their amplitudes attain a value of 1 – 2 nT. These variations are transferred from magnetospheric region by magnetoacoustic waves.
DKDP single crystals, dc electrical conductivity, concentration of L-defects, Gamma -irradiation, first order kinetics.
Vestnik KhNU ¹927 Pages. 22-30
The dependence of electrical dc conductivity of KD2PO4 (DKDP) single crystals on the dose of ?-irradiation is investigated. The conductivity is found to decrease exponentially in a dosage range of 3.0 102÷2.8 104 Gy. The temperature dependences of the conductivity are described by the exponential law. The pre-exponential factor and activation energy values of conductivity are determined for the crystals irradiated with various doses. Analysis of the dose and temperature dependences shows that the radiation-induced decrease of the conductivity is associated with the decrease of L-defect concentration in the crystal. The concentration changes in accordance with the law of first order kinetics. Possible mechanisms of the L-defect concentration changes under gamma -irradiation of crystals are discussed.
Gunn diode, dipole domain, accumulation layers, transit frequency, efficiency generations
Vestnik KhNU ¹927 Pages. 3-6
Results of research of power and frequency characteristics of Gunn diodes on the basis of Al1-xInxN for various values of concentration of impurity in active area in biharmonic regime are present. It is shown, that using of voltage of the complex form leads to increase of efficiency generation at the basic harmonic in comparison with work in harmonic regime. The increase of impurity concentration in active area leads to increase of efficiency generation both on the first, and on the second harmonic. At the expense of effective work on the second harmonic there is a possibility of reception of generation to frequencies of a submillimetric range.
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