ON BORN CORRECTION TO THE CROSS-SECTION OF RADIATION BY RELATIVISTIC ELECTRON IN EXTERNAL FIELD

N.F. Shul`ga, V.V. Boyko

Full Text :   (350 kB, Rus.) 

Abstract
Semiclassical formula for spectral-angular distribution of radiation by relativistic electron in external nongomogenuous field, which was obtained on the basis of operator semiclassical method with taking into account of recoil effect at radiation, is investigated. The decomposition of this formula on external field potential is fulfilled. The comparison of obtained result with the correspondingresultof Born calculation on the basis of Feynman diagrams method is fulfilled. The nonaccordance of semiclassical and second Born approximation results for the region of high energy photon is shown.

KEY WORDS: semiclassical approximation, Born approximation, probability of radiation, cross-action of radiation, cross-section of scattering.

FERMIONIC GENERALIZATION OF LINEAL GRAVITY IN CENTRALLY EXTENDED FORMULATION

S.A. Duplij, D.V. Soroka, V.A. Soroka

Full Text :   (170 kB, Eng.) 

Abstract
We generalize the central extension of the $(1+1)$-dimensional Poincar\'{e} algebra by including fermionic charges which obey not supersymmetric algebra, but special graded algebra containing in the right hand side a central element only. We verify selfconsistency of Jacobi identities and derive the Casimir operator. Then we introduce the correspondent gauge fields and construct the classical gauge theory based on this graded algebra, present field transformations and derive the black hole mass in $(1+1)$-dimensions.

KEY WORDS: Poincare algebra, lineal gravity, central extension, fermionic generator, Casimir operator.

RADIAL CONVECTIVE-DIFFUSION TRANSPORT, DEFINED BY PARTIALLY ORDERED CONVECTIVE DYNAMICS OF ELECTRONS

S.V. Barchuk, E.D. Volkov, V.I. Lapshin, V.I. Maslov

Full Text :   (390 kB, Rus.) 

Abstract
It is shown in this paper that during development of thе instability in crossed electric and magnetic fields in thermonuclear devices the ordered motion of convective cells (or large scale vortices) could appear due to radial density gradient. This correlation between vortices provides anomalous radial particle transport. The convective electron dynamics is described. The linear dispersion equation for signed vortices and the convective-diffusion equation for ordered structure of convective cells are obtained. The space structure of such convective cells is also obtained. Radial dimension of these cells depends on it's amplitude and radial density gradient.

KEY WORDS: anomalous radial transport, regulating of convective cells, convective-diffusion equation, vortical electron dynamics.

DISPERSIVE RATIO FOR THE RESONATOR WITH SINUSOIDALLY RIPPLED METAL WALLS, FILLED WITH COLD PLASMA

V.I. Lapshin, A.F. Stoyanov, I.V. Tkachenko

Full Text :   (250 kB, Rus.) 

Abstract
Electromagnetic waves extending in the limited periodic resonator, filled are described by cold plasma are described. Decisions of Maxwell's equations а for the plasma resonator, taking into account boundary conditions on vertical and goffered ideally conducting walls are found. It is shown, that the decision of Maxwell's equations and dispersive ratio are similar to the results received for an infinite periodic wave guide with one difference, that for longitudinal wave numbers the spectrum of own values is discrete. The amount of allowed values corresponds to amount of lengths of the periods, stacked on length of the resonator.

KEY WORDS: plasma, a wave guide, the resonator, metal, the period.

USE PIXE FOR DETERMINATION OF SCANDIUM IN NICKEL

O.P. Omelnyk, V.V. Levenets, A.O. Shchur

Full Text :   (570 kB, Rus.) 

Abstract
This article devoted to development of a technique and principles of the analysis of the contents of scandium in a nickel matrix with registration of protons induced characteristic x-ray emission. For achieve of the best analytical characteristics have been investigated influence on them of various parameters of measurement: energy of protons, a material of the x-ray filter and its thickness. Standard samples have been made. Metrological characteristics of the developed technique are investigated. With use of the developed technique and the modernized equipment the diffusion constant of scandium in nickel is determined.

KEY WORDS: protons, X-ray emission, scandium, nickel, diffusion.

SMOOTHING OF SURFACE DOSE DISTRIBUTION UNDER BREMSSTRAHLUNG IRRADIATING

V.T. Lazurik, S.A. Pismenetskiy, G.F. Popov, V.G. Rudychev, D.V. Rudychev

Full Text :   (510 kB, Rus.) 

Abstract
The model of computation of the dose fields in the objects formed by extensive converters is developed. Optimization of the angular and spatial distribution of electrons on a converter provides the maximal use of the bremsstrahlung energy. It is shown, that due to the set computation change of angles of incidence of electrons on a converter, it is possible substantially to decrease the inconstancy of the bremsstrahlung dose absorbed in an object. Correctness of offered approach is confirmed by the direct simulation by the methods of Monte Carlo (package GEANT 4).

KEY WORDS: radiation technology, bremsstrahlung, extensive converter, optimization method.

POWER EXTRAPOLATION OF EXPERIMENTAL RESPONSE FUNCTIONS OF ²Н AND ⁴Нe NUCLEI

A.Yu. Buki, I.A. Nenko, N.G. Shevchenko, I.S. Timchenko

Full Text :   (430 kB, Rus.) 

Abstract
To solve the problem of determining experimentally the moments of nuclear response functions, it is essential to extrapolate these functions to the region of high energy transfers, where the measurements are impossible. The present paper is concerned with the extrapolation of the response function through the use of the power function. For the purpose, the measured data on the ²H and ⁴Нe nuclei at momentum transfers between 0.9 and 1.5 fm^-1 were used. The derived exponent values of the extrapolation function are compared with the results of theoretical calculations.

KEY WORDS: atomic nuclei, electron scattering, response functions, extrapolation, power function.

OBTAINING OF INITIAL SUPERSONIC SPEED OF FLAME PROPAGATION BY PLASMA-WAVE SYSTEM

K.V. Korytchenko

Full Text :   (540 kB, Rus.) 

Abstract
A theoretical proof of requirements to a discharge's gap long and a "medium" tension of an electric field into an impulse arc using at a plasma-wave system has been made to provide an effective and quick transition of a discharge energy into a gas heat. Experimental results of a speed of a forward plasma front propagation, a plasma expansion and a speed of radial combustion into a mixture of an acetylene and an air have been shown.

KEY WORDS: discharge's gap, impulse arc, energy input, combustion initiation, plasma stream.

USING OF DUAL ENERGY METHOD FOR HIGH-Z ISOTOPES DISCRIMINATION

V.D. Afanasev, S.A. Pismenetskiy, V.G. Rudychev, D.V. Rudychev

Full Text :   (390 kB, Rus.) 

Abstract
An increase of sensitivity of dual energy method has been realized by the special forming of spectra of bremsstrahlung radiation (BR). The 1st BR beam is formed by electrons with energy of E_е < 4 MeV, the energy of 2nd beam is not limited from above. In both cases the filters are used. The method of determination of average mass thickness of the inspected objects is developed. On a masking background it is possible to select the enclosure of heavy materials with a mass thickness about 10 g/sm².

KEY WORDS: high-Z isotopes discrimination, bremsstrahlung, dual energy.

NUMERICAL SIMULATIONS OF RECONSTRUCTION PROBLEM POINTED AT PROFILE OF IMPURITY CONCENTRATION USING PIXEL

I.K. Kovalchuk, V.V. Levenets, A.O. Shchur, M.P. Kozhevnikova

Full Text :   (430 kB, Rus.) 

Abstract
The reconstruction algorithms of concentration profiles using measurements of characteristic X-ray emission yields induced by protons in thick targets at various energies of protons are considered in work. Four kinds of profiles are considered: increasing, subsiding, permanent and Gaussian. Reconstruction of profiles was made by method of maximum likelihood and a method of regularization by Tikhonov. The yields of X-ray emission from a sample were modeled without error, and with an error having Gaussian distribution. The quality of restoration of profiles by both methods for preset levels of X-ray emission yield error and influence of maximum likelihood method error and parameter of regularization by Tikhonov on character of restoration was estimated. It was established, that in absence of error at definition of an X-ray emission yield the method of maximum likelihood allows to reconstruct a test profile safetyly (with accuracy up to 5-6%), quality of restoration is worsened with increase of error, and at a relative error of 8 % restoration of profiles has became impossible. It was shown, that the method of maximum likelihood allows restoring a profile of an impurity more safetyly in a probed sample as contrasted to a method of regularization.

KEY WORDS: characteristic X-ray emission, ill-posed problems, method of maximum likelihood, method of regularization, instability of solution, restoration of profile of impurity.

ELECTROPHYSICAL AND STRUCTURAL AND PHASE CHARAKTERISTICS OF THIN-FILM COMPOSITS Cr-N AND V-N

A.G. Guglya

Full Text :   (320 kB, Rus.) 

Abstract
The investigation of structure and phase characteristics and conductivity of CrN and VN films prepared by ion beam assisted deposition was studied. It was shown that nitrogen ion bombardment during chromium and vanadium deposition forms nanocrystalline structures. The grain size and boundary morphology are different for both materials. The annealing at 500°C during 2 hours shown that the boundary structure is very important for these materials conductivity. The metallic electrical resistivity of CrN was connected with narrow depth of grain boundary. Vanadium nitride has broad amorphous boundaries. This fact is a course of negative thermal resistivity coefficient. From other side the morphology of these boundaries influences on stability electric characteristics of vanadium nitride.

KEY WORDS: chromium nitride, resistivity, vanadium nitride, ion beam assisted deposition, amorphous structure, thermal resistivity coefficient.

INFLUENCE OF ION IRRADIATION ON THE STRUCTURE OF THE NANOCRYSTALLINE PHASE INCLUSIONS IN ZR-FE⁵⁷ ALLOYS UNDER NIOBIUM DOPING

V.G. Kirichenkо, A.I. Kirdin

Full Text :   (260 kB, Rus.) 

Abstract
By using Conversion Electron Mossbauer Spectroscopy the investigation of structure and subsurface layers of ternary alloys Zr-Fe-Nb after irradiation by heavy ions was carried out. The compositional and structural heterogeneity of subsurface layers is discovered. It is caused by nanocrystalline particles migration of iron contained intermetallic inclusions into surface layers under thermal aging at temperature range 570÷1070 K. Irradiation by Fe⁴⁺ ions fluence 2·10²¹ м^-2 under temperature Т=300 К of Zr-0,31%Fe-0,5%Nb alloy lead to change of intermetallide phase composition in subsurface layers about 0,3 μm depth. Irradiation lead to transition of iron atoms from crystalline phase (Zr_1-xNb_x)₂Fe to phase (Zr_1-xNb_x)Fe₂ and to amorphous phase. Under isochronous aging at range 370÷970 К the inverse transition of iron atoms into metastable phase (Zr_1-xNb_x)₂Fe is observed on the irradiated surface of alloy. On the unirradiated surface of alloy the formation of intermetallic inclusions and the transition of iron atoms into stable phase (Zr_1-xNb_x)Fe₂ is finished at Т=470 К.

KEY WORDS: zirconium alloys, surface, intermetallic inclusions, segregation, irradiation, ions.

ION IRRADIATION EFFECT ON THE INTERNAL MICROSTRESSES IN NIOBIUM FILMS. COMPUTER SIMULATION

I.G. Marchenko

Full Text :   (270 kB, Rus.) 

Abstract
The effect of low-energy irradiation with internal ions on the microstresses created in niobium films was studied by the method of molecular dynamics. The ion flow made up 10% of the total flow of deposited atoms, the ion energy was 200 eV. Atom-ion deposition of the film was performed after thermal deposition of the film at a temperature of 300 K to the thickness at which a steady density can be reached. It is shown that the ion influence leads to the change in the character of internal microstresses. This change occurs due to formation of interstitial atom clusters which appear as a result of developing the cascades of atom-atom collisions. These clusters can be as nuclei of interstitial dislocation loops that were observed in experiments on the ion irradiation effect on the film properties. The correlation between the density of films being formed, their microstructure and microstresses created was revealed.

KEY WORDS: films, microstresses, physical vacuum deposition, ions, computer simulation, niobium.

INVESTIGATION OF ELECTRON BEAM STABILITY IN SOURCES WITH A SECONDARY-EMISSION CATHODE

N.I. Ayzatskiy, V.N. Boriskin, A.N. Dovbnya, V.V. Zakutin, N.G. Reshetnyak, N.A. Dovbnya, T.A. Kovalenko

Full Text :    (280 kB, Rus.) 

Abstract
Investigation of beam parameters in electron sources with secondary-emissin cathodes in crossed electric and magnetic fields was carried out. Momentary and lasting stability of beam current amplitude and cathode tension is 3-5 %. Beam current distribution during the impulse was investigated. It is shown that momentary stability of beam current amplitude can achieve value ~ 1…2%. The analysis of factors are influenced on stability of electron beam parameters was carried out.

KEY WORDS: secondary emission, electron beam, stability, electric field, magnetic field.

INFLUENCE CONSECUTIVE REMELTS ON STRUCTURE AND PHYSICOMECHANICAL PROPERTIES OF NICKEL ALLOY REMANIUM CSe

V.I. Dotsenko, M.A. Tikhonovsky, E.A. Chaika

Full Text :   (520 kB, Rus.) 

Abstract
The complex analysis of firm and recast, after 6 series remelts, dental alloy Remanium CSe of system Ni-Cr-Mo structure both physical-mechanical properties was conducted. It was determined, that the sixfold series remelts of an alloy gives some diminution of material strength properties. Some samples, since the fifth remelt, find out brittle behavior resulting in to diminution of strength. On surfaces of fracture after the fifth and sixth remelts there were tracks of oxides and carbides. The parent of occurrence of oxides and carbides are the surface layers of a remelted material, that indicates a key opportunity of elimination of this undesirable effect by more careful surfacing before remelting. The preliminary results showing prospects of such approach we had already obtained. It allows to hope that the recycling of an alloy Remanium CSe is basically possible.

KEY WORDS: dental alloys, Remanium CSe alloy, microstructure, mechanical properties, recirculation.

RECEPTION OF FINE-GRAINED TANTALUM

I.I. Papirov, M.A. Tikhonovsky, V.S. Shokurov, A.I. Pikalov, V.S. Sivtsov, G.E. Storozhilov, T.G. Emljaninova, A.I. Mazin, V.A. Shkuropatenko

Full Text :   (380 kB, Rus.) 

Abstract
Results of ultra fine-grained tantalum (grain size of 3 - 5 microns) reception are presented in the article. Such metal possesses the improved mechanical properties: ultimate strength ~ 600 МРа, relative elongation - 30-35 %. Ultra fine-grained tantalum has been received by an alternating of pressure processing and heat treatment. Perspective of its using as a material of coronary stents is shown.

KEY WORDS: ultra fine-grained tantalum, deformation processing, recrystallization annealing, coronary stent.

THE FLUCTUATION CONDUCTIVITY OF Y_1-zPr_zBa₂Cu₃O_7-x SINGLE CRYSTALS WITH GIVEN TOPOLOGY OF FLAT DEFECTS

M.A. Obolenskii, R.V. Vovk, A.V. Bondarenko, O.V. Bogdan

Full Text :   (320 kB, Ukr.) 

Abstract
In present work the conductivity of YВaCuO and Y_1-zPr_zBa₂Cu₃O_7-x single crystals in the normal and superconductivity state are investigated. It is shown that fluctuation conductivity satisfactory described by Lawrence-Doniach model. The Pr admixtures are the effective scattering centers of normal and fluctuation carriers. Partial replacement Y on Pr results in formation of two superconductivity phases with different critical temperatures.

KEY WORDS: fluctuation conductivity, adding, YВaCuO single crystals, high temperature superconductivity, crossover, length of coherent.

MАСROSCOPIC EQUATIONS FOR DESCRIPTION OF ECONOMIC ENGINEERING SYSTEMS WITH MASS PRODUCTION OUTPUT

V.P. Demutsky, V.S. Pignastaya, O.M. Pignasty

Full Text :   (260 kB, Rus.) 

Abstract
A mathematical model of mass production dynamics in engineering is constructed. The state of production system at any moment is given by a point in two-dimentional phase space. Distribution function for base product is introduced and the equation for this function is written. There is the analogy of kinetic equation in physics. The engineering-production and generative functions are defined.

KEY WORDS: synergetic, basic product, macroscopic description, distribution function, engineering-production function, generative function, equations of balance.

TISSUE-MIMICKING PHANTOMS AND TISSUES IN VITRO HEATING AND THERMAL DESTRUCTION CONTROLLED BY ACOUSTICAL PALPATION WITH ULTRASOUND DOPPLER DETECTION

E.A. Barannik, S.A. Girnyk, A.E. Barannik, V.V. Tovstiak

Full Text :   (290 kB, Rus.) 

Abstract
Increasing of shear strain magnitude with temperature rise in samples of biological tissues in vitro and tissue phantoms is researched. It is shown, that a method of acoustic palpation by means of radiation pressure force and ultrasonic Doppler detection yield the key capability for noninvasive monitoring in real time of process of ultrasonic thermal tissue destruction. At that the thermal destruction is possible under action of the same wavebeam which creates radiation force. It is fixed, that fluctuating character of change of detected shear displacements is the indicator of the beginning of phase transformation of the I-st kind in examined area of biological object.

KEY WORDS: acoustical palpation, hyperthermia, radiation pressure, shear deformation, Doppler probing, change of phase.