http://dspace.nbuv.gov.ua:80/handle/123456789/114721 Tue, 14 Apr 2026 13:03:27 GMT 2026-04-14T13:03:27Z http://dspace.nbuv.gov.ua:80/bitstream/id/341504/ http://dspace.nbuv.gov.ua:80/handle/123456789/114721 http://dspace.nbuv.gov.ua:80/handle/123456789/120499 Spectroscopical study of natural nanostructured carbonaceous material shungite Konchits, A.A.; Shanina, B.D.; Valakh, M.Ya.; Yanchuk, I.B.; Yukhymchuk, V.O.; Yefanov, A.V.; Krasnovyd, S.V.; Skoryk, M.A. The correlation between morphology, local structure and magnetic properties of the different origin shungite material with nanocarbon content 25-40 wt. % was studied by SEM, EPR, and Raman scattering methods. It was established that structure of the shungite samples is formed by micron size agglomerations of carbon and silicon dioxide clusters with impregnations of pyrite (FeS₂), iron oxide and aluminium oxide particles. It was found from the Raman data that nanocarbon fraction is formed from sp²-hybridized well ordered carbon clusters, size of which increases from 9 nm up to 12 nm after annealing of the samples. It was found for the first time that origin of L3 and L4 EPR lines is due to oxy-deficiency centers in the silicon dioxide clusters. Wed, 01 Jan 2014 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/120499 2014-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/120498 Energy transfer in co-doped NaI:(Tl,Eu) crystals Gridin, S.; Vasyukov, S.; Shiran, N.; Gektin, A. The energy transfer mechanism in Eu doped and Tl, Eu co-doped NaI crystals is discussed. The self-trapped exciton emission band overlaps stronger with Eu²⁺ excitation bands rather that with Tl⁺. This suggests that transfer STE -> Activator can be more efficient in Eu²⁺ co-doped NaI:Tl crystals. Theoretical estimation of energy transfer efficiency was done based on the Forster model. It is shown that Europium concentration of 1 mass% or above is required for efficient dipole-dipole energy transfer. However, this concentration is not reachable in NaI:(Tl,Eu) due to the solubility limit of Eu²⁺ in NaI crystal. Wed, 01 Jan 2014 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/120498 2014-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/120497 Characterization and photocatalytic activity of Ti/TinOm •ZrxOy coatings for azo-dye degradation Sakhnenko, N.D.; Ved, M.V.; Bykanova, V.V. Anodic oxidation of VT1-0 titanium and E-125 zirconium alloy in aqueous electrolyte solutions based on H₂SO₄ and K₄P₂O₇ was used to obtain oxide coatings composed of Zr/ZrO₂, Ti/TiO₂, and mixed oxide systems Ti/TinOm•ZrxOy. It was shown that, depending on the electrolyte pH, the films contain up 0.17 to 2.1 % wt. of zirconium. Catalytic activity of the synthesized coatings in the oxidation reaction of methyl orange azo dye under UV irradiation was established. The process rate constants and synergy factors for the mixed systems were calculated. Wed, 01 Jan 2014 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/120497 2014-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/120496 Effect of microwave sintering temperature on structure and properties of bioceramics based on biogenic hydroxyapatite Tovstonoh, H.; Sych, O.; Skorokhod, V. The present work demonstrates the possibility to produce medicine-aimed ceramics on the basis of biogenic hydroxyapatite with structural-mechanical properties required for replacement of the bone tissue defects using techniques of microwave sintering at 800-1100°C. It has been established that porosity of the bioceramics obtained in the temperature range of 800-1000°C (5 min exposure to the maximal temperature) equals about 40 %, whereas at 1100°C it decreases down to 37 %. Compression strength increases with increasing the temperature from 25 to 38 MPa. Wed, 01 Jan 2014 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/120496 2014-01-01T00:00:00Z