[en] Proposed is an approximatjon hybrid mathematical model for optimization of systems with distributed parameters and a complex geometry described by the differential equations with partial derivatives of the parabolic type with a complex boundary. The system state and control functions, as well as the rates of their change are restricted by inequalities, consequently, the optimum control function is considered as a conditional one. The numerical method and algorithm for serching the condi onal control function leading out the system into the given state for the minimum period of time is proposed. The algorithm for serching the optimum control function is realized on the computer and its ability are illustrated while calculating the system of a cylindrical one-dimensional geometry

No abstract available

No abstract available

[en] A technology has been developed for electroslag melting of connecting pipes, including composite types, on cold shells and those heated to 200 deg C. The composite connecting pipes are formed using a consumable electrode involving portions of steels 22K and OKh18N10T separated with a nickel spacer whose function is to exclude cracking in the transition zone. Fatigue strength tests and metallographic studies have shown a complete compliance of the metal with the requirements for welded joints to be used in atomic power engineering

[en] Studied are thermal cycle during electroslag melting of branch pipes for NPP equipment vessels, made of the 22K steel, the level of residual stresses, effect of thermal strain cycle of the melting on the energy of crack initiation and propagation as well as the hydrogen effect on energy capacity of branch pipe metal fracture and of zone of its connection with article. Effect of enumerated factors in the metal of heat affected zone of branch pipes of electroslag melting on the energy of crack initiation is considered. Preliminary and accompaning heating is recommended to eliminate the possibility of defect appearance

[en] The carried out interpretation of vibration spectra of polycrystal compounds of the scheelite structure with application of the fragmentary calculation method allows one to determine the value of contribution of internal and external natural coordinates to vibrations of anion. The effect of the cation mass on values of frequencies and forms of deformation vibrations and of crystal lattice vibrations is revealed. The characteristic with respect to the form components of deformation vibrations of anion are determined. Thus, the calculation carried out shows the possibility of application of the fragments method for analyzing the intraanion vibrations and the crystal lattice vibrations of scheelite structures

[en] A technology has been developed for the electron-beam welding of drive components intended for the vertical displacement of control rods in the WWER-1000 reactor. The drive housing of dissimilar steels OKh17N and 08Kh18N10T is at the same time a stator of a linear step motor. The stator is made in the form of a welded tubular structure from four-phases of steel OKh17N, separated by four longitudinal circular inserts from austenitic steel 08Kh18N10T. The longitudinal and circular welds of magnet-soft steel OKh17N and nonmagnet steel 08Kh18N10T are made by using an electron-beam welder. The optimum heat treatment conditions of the welded joints for these steels (680 deg C for 5 h) have been found, ensuring levelling their hardness and increasing impact viscosity and intercrystalline corrosion-resistance properties in the heat-affected zone. Tests of the samples have confirmed the operation reliability and performance of the welded joints

[en] Methods and results of remote measurements of relative changes in conversion coefficient, brightness of background and luminosity of electron-optical converter screen under effect of continuous and pulsed ionizing radiations, are presented

[en] In order to further specify the dynamics of intramolecular oscillations in the K₅(UO₂)₂F₉ complex and their relationship to the geometrical parameters of the complex, a study was carried out on spectral-luminescent properties and normal oscillations were calculated for the [(UO₂)₂F₉]^5- complex anion. The infrared absorption spectra and Raman spectra were measured. Oscillations of the anion were calculated with the use of several theoretical models differing in the length of U-F bonds. The vibration spectrum of K₅(UO₂)₂F₉ contained no degenerate oscillations, because of decreased symmetry of [(UO₂)₂F₉]^5-. All the observed spectra of K₃UO₂F₅ and K₅(UO₂)₂F₉ contained frequency of approximately 130 cm^-1, which was presumably due to external interactions of uranyl anion with potassium cation

[en] Physical processes, determining anode current (Isub(a)) change of photoelectron multipliers (PEM) with antimony-cesium photocathodes under pulsed gamma and neutron radiation, are determined. The Isub(a) amplitude under pulsed gamma and neutron radiation is shown to be determined by the gamma component, and at dose rate of the order of 10⁷ R/s it is close to multiplier current being equal to 3x10sup(-4) A. Isub(a) dependence after radiation pulse at fluence 2x10¹⁴-10¹¹ neutr/cm² is determined by currents caused by fluorescence and induced activity of structural materials