http://dspace.nbuv.gov.ua:80/handle/123456789/114626 2026-04-05T23:03:40Z http://dspace.nbuv.gov.ua:80/handle/123456789/121458 On the collection of photocurrent in solar cells with a contact grid Sachenko, A.V.; Gorban, A.P. The exact solution for the dependence of specific power of photoconversion in the mode of maximum collected power on distance l between lines of the contact grid has been obtained. It is shown that in an optimized case, when the change of the potential of heavily doped front layer under contacts and between contacts is less than kT/q, the characteristic length L can be introduced with a meaning of the distance at which the photocurrent reduces by a factor of e due to recombination. Variation of the filling factor of SC IVC due to the presence of contact grid is then analytically expressed via this length. It is found that in unoptimized case, when the distance between contact strips l is much longer than L, the photocurrent collection is determined by lesser, as compared to L, distance, at which the front layer potential changes from the value of Vm under contacts to the open- circuit voltage between the contacts. In this case the change of IVC filling factor due to the presence of contact grid is expressed again analytically via this new characteristic length. In the intermediate case, when l ≈ L, the solution of the problem can be found by numerical methods only. 1999-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/120261 Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix Dyadyusha, A.G.; Gvozdovsky, I.A.; Salkova, E.N.; Terenetskaya, I.P. A new approach to the problem of personal UV biodosimeter is described. Nematic liquid crystal (LC-805) is converted into induced cholesteric phase using photosensitive chiral dopant of steroid biomolecules (7-dehydrocholesterol (provitamin D3) or 7-DHC-benzoate). Significant changes in optical characteristics of the LC films depending on the duration of UV exposure are observed as a result of UV initiated photoisomerizations that change helical twisting power of dopant molecules. 1999-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/120260 Residual atmosphere in vacuum fluorescent displays Finkelshtein, S.H.; Sorokin, V.M.; Rakitin, S.A.; Sevostyanov, V.P. This paper is devoted to problems of gassing in vacuum fluorescent displays (VFD). Technique of qualitative and quantitative analysis of residual atmosphere in VFDs is presented. Also, dynamics of residual gas pressure under different modes of VFD operation is considered. 1999-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/120259 Crystals Cd₁₋x ZnxTe – a promising material for non-cryogenic semiconductor detectors: preparations, structure defectness and electrophysical properties Atroshchenko, L.V.; Galkin, S.N.; Galchinetskii, L.P.; Lalayants, A.I.; Rybalka, I.A.; Ryzhikov, V.D.; Silin, V.I.; Starzhinskii, N.G. Relationship between preparation conditions of the raw charge, crucible material, growth regimes and structure defectness and electrophysical properties of crystals Cd₁₋x ZnxTe has been studied. The crystals were grown both from the raw material which had been pre-synthesized in quartz ampoules and from the raw material synthesized from the elements directly in the growth furnace. It is shown that the best values of electric resistivity ρ (up to 10¹¹ Ohm⋅cm) and sensitivity to X-ray and gamma-radiation are obtained for crystals grown in crucibles of highly pure coal-graphite material from the pre-synthesized raw charge. Correlation has been established between values of ρ and crystal defectness: decrease of dislocation density by 10⁴ times led to 10⁷ times higher values of resistivity. Concentration of dislocation etching pits regularly decreased with higher purity of the raw material and optimization of crystal preparation technology. 1999-01-01T00:00:00Z