Vol 5, No 2 (2021)
70-87 322

One of the most complicated problems of experimental nuclear physics is the synthesis of exotic nuclei near the boundaries of stability. These nuclei, as a rule, are 10 or more neutrons awayfrom stable nuclei, have a short lifetime (less than 1 ms) and low binding energy. All this determines special requirements to the choice of reactions for the synthesis of such nuclei and the method of their transportation and registration. Mainly, for the synthesis of exotic nuclei, reactions of fragmentation of the bombarding heavy ion, direct reactions of the types ( p,d) , (d, p) , (d,n) ,( d , 3 He), etc., as well as reactions of fission and deep inelastic transfer are used.

88-101 353

A time-of-flight system was created to register the reaction products and perform correlation measurements on a high-resolution magnetic analyzer (MAVR). The facility is located on the channel of the extracted beam of the U-400 cyclotron at the Laboratory of Nuclear Reactions JINR. The results of measuring the parameters of the time-of-flight spectrometer obtained on the basis of measuring the spontaneous fission fragments velocities of 252Cf are described. In addition, the results of the measurement of fission fragments in the 48Ca+238U reaction are presented. In this case, two time-of-flight arms were used, with the help of it is planned to carry out correlation measurements of induced fission fragments of a complex system. The created system also makes it possible to carry out correlation (three particles) measurements of fission fragments with particles registered in the focal plane of the MAVR magnetic spectrometer. Another purpose of the described system is to register elastically scattered ions, which is used as a monitoring system for the quality and composition of the beam hitting on the target of the MAVR facility.

102-115 303

In this study, corrosion behaviors of diffuser unit solutionbywhich raw sugar is produced from minced sugar beets in sugar factories on St-37 low alloy steel and AISI 304, 304L, 316 austenitic stainless steel types were examined. Moreover, influence of heat treatment on corrosion resistance was investigated. Corrosion tests were performed using mass loss method. SEM-EDX, X-rays Diffraction, microhardness and surface hardness analyses of samples were carried out. As a result, it was determined that AISI 304L and 316 steels have better corrosive resistance and heat treatment improves corrosion resistance.

116-125 368

In the present paper,we report the structural optimization of intercalated CrTiS2 compound by using Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA) through Quantum ESPRESSO code. All the computations are carried out by using an ultra soft pseudopotential. The effect of charge transfer from guest 3d transition metal Cr-atom to self-intercalated compound TiS2 has been studied. In electronic properties, the energy band structure, total density of states (TDOS), partial density of states (PDOS) and Fermi surface have carried out. From the energy band structure, we conclude that the TiS2 intercalated compound hasa small bandgap while the doped compound with guest Cr-atom has metallic behavior as shown form its overlapped band structure.

126-132 326

This article is devoted to the study of determination of gamma radiation shielding efficiency by new radiation-resistant glasses of the 0.5TeO2-(0.5-x)Bi2O3-xWO3 type. Asa method of obtaining glasses, the method of solid-phase synthesis combined with thermal annealing and subsequent hardening was used. The amorphous nature of the synthesized samples was confirmed by X-ray phase analysis. Determination of the shielding ef ficiency, as well as the effect of Bi2O3 and WO3 content in the glass composition on the attenuation efficiency was carried out by evaluation of gamma radiation intensi 137Cs ties from the source, with a gamma ray energy of 661 keV. The evaluation was performed on parameters such as radiation protection efficiency, linear and mass attenuation coefficients, half-value layer and mean free path. During the studies, it was found that glasses of the following composition 0.5TeO2-0.1Bi2O3-0.4WO3 are most effective, which are 1.3-2 times higher than those of the composition 0.5TeO2-0.4Bi2O3-0.1WO3.

133-139 367

The synthesized SrSO4 crystalline powders were irradiated at photon energies from 6 . 12 eV, in the temperature range from 15 . 300K. The investigationwas carried outbythe methodsof atomic absorp tion, luminescence and vacuum ultraviolet spectroscopy. Intrinsic emissions were found at 3.7-3.8 eV, 4.2-4.6 eV and 4.9-5 eV, and long-wavelength recombination emissions at 2.6-2.7 eV and 2.9-3.0 eV.The synthesized SrSO4 crystalline powders were irradiated at photon energies from 6 . 12 eV, in the tem perature range from 15 . 300K. The investigationwas carried outbythe methodsof atomic absorption, luminescence and vacuum ultraviolet spectroscopy. Intrinsic emissions were found at 3.7-3.8 eV, 4.2-4.6 eV and 4.9-5 eV, and long-wavelength recombination emissions at 2.6-2.7 eV and 2.9-3.0 eV.

140-147 370

In thepresent work, the emission and excitation spectrain Li2SO4-Cu crystalshave been obtainedby the methods of vacuum-ultraviolet and thermoactivation spectroscopy. We have studied the nature of emission from a pressed and annealed sample of Li2SO4-Cu powders. It has been revealed that at low temperatures Cu0-SO. -centers are formed during the trap of electrons by Cu+ -centers and during 4 localization of SO. 4 -radicals in the form of localized hole centers.

148-154 359

This work were studied the effect of technological parameters of detonation spraying on the phase composition and tribological characteristics on the bases of NiCr and Al2O3 coatings. As well as therewas obtained and investigated multilayer coating on the basesof NiCr/NiCr-Al2O3/Al2O3. It was determined that during detonation spraying the phase composition of Al2O3 coatings strongly depends on the degree of filling the borehole with a gas mixture. The . -Al2O3 -phase content in the coatings increases when the degree of filling is 63% and 54%. Only one CrNi3 phase is observed on the diffractograms and only increase of reflex intensity (020) at barrel filling by 58% is observed by sputtering on the bases of NiCr coatings in different degrees of barrel filling. The results of the coating nanohardness study showed that the hardness of the Al2O3 coating increases depending on the content of . -Al2O3 in it. Al2O3 coating has the maximum nanohardness values and is 16.42 GPa at the borehole is filled to 63%. The nanohardness of NiCr coating has the maximum values at barrel fillingby58% and consisting of 8.02 GPa.

155-162 359

This work are presented the research results of pulse plasma treatment influence on the phase composition, hardness, roughness and element composition of coatings on the bases of Fe-TiB2-CrB2. The Fe-TiB2-CrB2 coatingwas depositedby detonation method. The following pulse-plasmatreatment was used to modify the structure and properties of the surface layers of the sprayed coating. The results of mechanical experiments showed that the hardness of Fe-TiB2-CrB2 coating increased after the treatment. On the basis of the X-ray analysis, it has been established that the increase of coating hardness is connected with phase transformations in a surface layer, in particular, with formation of oxide phases and increase of carbide particles quantity.

ISSN 2522-9869 (Print)
ISSN 2616-8537 (Online)