Vol 1, No 2 (2017)
5-18 411

The article presents working results of radiation status survey in the territory adjacent to the "Atomic lake", a venue of the first USSR excavation explosion. In the course of research, a picture of areal radiation contamination has been obtained in the territory with technogenic radionuclides137Cs ,241Am ,152Eu . A pattern of radionuclide distribution in depth is shown at different spots (crater bank, Shagan river floodplain, the area of the external reservoir). Data is presented on concentrations of technogenic radionuclides3H,239+240,238Pu ,90Sr ,60Co ,154Eu ,152Eu in soil.

19-39 378

This work is an attempt to present some problems on the evolution of the Universe: the nucleosynthesis and cosmochronology from the standpoint of physics of particles and nuclei, in particular with the use of the lat est results, obtained by means of radioactive nuclear beams. The comparison is made between the processes taking place in the Universe and the mechanisms of for mation and decay of nuclei, as well as of their interaction at different energies. Examples are given to show the capabilities of nuclear physics methods for studying cosmic objects and properties of the Universe. The results of investigations in nuclear reactions, induced by radioactive nuclear beams, make it possible to analyze the nucleosynthesis scenario in the region of light elements in a new manner.

40-49 403

The results of studies of the ionic conductivity and the conjugated chemical diffusion coefficients (CCDC) in the nonstoichiometric LixCu1.75Se(0 ≤ x ≤ 0.25) ternary alloys are presented. It has been observed that the values of the ionic conductivity of Cu1.75Se copper selenide decreases with lithium doping in general owing to increasing the the activation energy. The increasing of the conjugate chemical diffusion coefficients of the cations and electron holes was observed with increasing of lithium content, despite the decreasing of self-diffusion coefficients of the cations and decreasing of electron mobilities. The behavior of the conjugate chemical diffusion coefficients explained by a decrease in the degree of non-stoichiometry of the composition, leading to an increase of the internal electric field accelerating the motion of slower particles.

50-54 385

Angular distributions of protons, deuterons, tritons and alpha particles emitted in the reaction2H +9Be at E lab =19.5 MeV were measured with an aim to shed light on the internal cluster structure of 9 Be and to study possible cluster transfer of5He. The analyses suggest a significant contribution of five nucleon transfer in the reaction channel9Be ( d ,4He)7Li.

55-60 389

During the last 12 years using the GABRIELA (Gamma Alpha Beta Recoil Invetsigations with the ELectromagnetic Analyser) detector set up and kinematic recoil separators VASSILISSA / SHELS the experiments aimed to the gamma and electron spectroscopy of the Fm-Db isotopes, formed at the complete fusion reactions48Ca +207,208Pb--255,256 No* ,48Ca +209Bi--257Lr* ,22Ne+238U--260No*,50Ti +208Pb--258Rf* and50Ti +209Bi--259Db* , were performed at FLNR JINR.

61-64 377

Inclusive energy spectra have been measured for light charged particles emitted in the bombardment of Ta target by48Ca ions at 261 MeV and 471 MeV. The reaction products were analyzed and detected by means of a (∆E-E) telescope placed in the focal plane of a magnetic spectrometer located at forward angles with respect to the beam direction. In all the reactions studied light charged particles with an energy close to the respective calculated kinematic limit for a two-body exit channel are produced with relatively great probability. The results obtained make it possible to draw some conclusions about the reaction mechanism involving the emission of light charged particles.

65-73 426

Neutron-removal cross-section ( σ-xn ) measurements of neutron-rich light nuclei were performed on the COMBAS fragment-separator with a multi-detector Si telescope at intermediate energies (22-34) MeV/nucleon. The removals of one neutron from8Li and9Be, two neutrons from6 He and10 Be and four neutrons from 8 He were observed from the reactions on a Si-CsI(Tl) telescope. Results of σ-xn for6 He,8 He,8 Li,9 Be and10 Be nuclei were obtained and compared with those of previously measured data. The data indicate that4 He is a good core within6 He and8 He. Furthermore, we found that9,10 Be nuclei disintegrated by one- and two- neutron removal reaction, respectively.

74-80 410

This paper is a generalization of the authors’ works in the field of asphaltene physics fulfilled in recent years. Specific features of the "insulator-semiconductor" phase transition in high-boiling hydrocarbon fractions are discussed. It is shown that the active resistance of the samples decreases with heating to (65 - 85)0 C. At the same time, the concentration of paramagnetic centers increases, which is confirmed by the EPR. The growth of electrical conductivity in high-boiling hydrocarbon fractions containing asphaltenes is caused by the temperature generation of charge carriers - free radicals (spins) formed as a result of the rupture of weak carbon-carbon bonds in molecules weakened by conjugation with aromatic rings. The energy of rupture of such bonds is rather low and can be as low as 40 kJ/mol. All these facts confirm the hypothesis of the authors that in the samples a phase transition occurs from the "insulator" state to the "semiconductor" state. The dielectric-semiconductor phase transition is also due to the generation of stable free radicals, since they are strong electron acceptors and reduce the width of the forbidden band of the material. Quantum-chemical calculations confirm this hypothesis. In addition, quantum-chemical calculations of the supramolecular, molecular, and electronic structure of asphaltene nanoparticles have been carried out. An experimental study of asphaltene crystallites by the AFM method was carried out. Theoretical calculations are reasonably confirmed by the AFM data.

81-86 387

We have developed method of preparation of luminescent polymer films based on polyvinyl alcohol (PVA), organic dyestilben 420 (St420) and silver nanoparticles (AgNPs). Concentration of St420 which provides most efficient luminescence quantum yield was determined for PVA film. It was found that addition of 10 nm AgNPs to St420 samples in PVA leads to increase of absorption intensity and decrease of luminescence intensity. Quenching of emission of St420 by addition of AgNPs is probably due to charge transfer from the dye to metal nanoparticles. External quantum efficiency (EQE) curves of St420 PVA were measured for optimal concentration of the dye. Some decrease of EQE curve was observed for down-shifting (DS) layer of St420. At the same time some increase of efficacy ofsolar cell (SC) was observed based on I-V measurements.

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