http://dspace.nbuv.gov.ua:80/handle/123456789/114592 Mon, 06 Apr 2026 12:51:56 GMT 2026-04-06T12:51:56Z http://dspace.nbuv.gov.ua:80/bitstream/id/341203/ http://dspace.nbuv.gov.ua:80/handle/123456789/114592 http://dspace.nbuv.gov.ua:80/handle/123456789/121597 Dynamic electrophysical characterization of porous silicon humidity sensing Bravina, S.; Morozovsky, N.; Boukroub, R. The results of the investigation of changes of parameters of bipolar and unipolar dynamic current-voltage characteristics and transient currents as well as dynamic bipolar charge-voltage loops connected with the pulse change of humidity for the samples of por-Si are presented. The hysteresis view of charge-voltage and current-voltage curves is characteristic for poling processes in the space charge region similar to that observed in the case of typical ionic conductors. Observed phases of transformation of investigated electrophysical characteristics reflect the time sсale of processes in the consequence “adsorption – dissociation and transfer – desorption”. The efficiency of using the methods of dynamic electrophysical characterization for studying characteristics of porous materials under fast humidity changes was demonstrated. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121597 2006-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/121596 Absorption and photoluminescent spectra of dimethylaniline ethylene ketone dyes in isotropic solvents Gorishnyi, M.P.; Shevchuk, A.F.; Manzhara, V.S.; Koval'chuk, A.V.; Koval'chuk, T.N. Absorption and photoluminescent spectra of dimethylaniline ethylene ketone dyes of two types K1 and K2 in a series of isotropic solvents were studied. It was shown that the photoluminescent spectra depend both on nature of solvent (formation of associates with solvent owing to hydrogen bonds between the dye and alcohol or aggregates of dye molecules) and the dye concentration (concentration decay). The frequencies of electron transitions and frequency of intramolecular fluctuation were determined, and conclusions concerning the nature of absorption bands were made. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121596 2006-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/121595 Simulation of radiation characteristics of pulse X-ray devices for non-destructive testing the semiconductor materials Denbnovetsky, S.V.; Slobodyan, N.V. In the work, non-destructive testing the Si and Ge semiconductors by pulse X-ray sources is discussed. Mathematical simulation of the radiation generation in reflection and transmission anode tubes is performed. Details of energy spectrum formation in these pulse tubes are analyzed, and its transformation when passing through thin samples of semiconductor materials is discussed. The dependence of the amount of radiation absorbed by the samples on the amplitude of acceleration voltage is calculated. It is shown how the pulse operation regime and design features of pulse tubes influence the characteristics of the X-ray radiation. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121595 2006-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/121594 New fast-relaxed liquid crystal materials for optical communication networks Garbovskiy, Yu.; Sadovenko, A.; Koval'chuk, A.; Klimusheva, G.; Bugaychuk, S. Recording the dynamic holograms with microsecond relaxation times under action of laser pulses was obtained in composites based on the novel class of liquid crystals (LC), namely in ionic metal-alkanoates. Holographic parameters of the recording and relaxation characteristics were studied for doped lyotropic ionic LC and sandwich-like cells with photo-sensitive impurities for purposes of real-time dynamic holography applications. The thin cells demonstrate high-velocity dynamic grating recording under laser pulses both of nanosecond and picosecond durations at the visible wavelengths. The cells exhibit a fast temperature relaxation time (with the time constant 30 μs for the store heat density more than 50 kJ/s). Ionic lyotropic smectic LCs possess a high intrinsic anisotropic conductivity as compared with other LCs – dielectrics. To explain the relaxation mechanisms in ionic smectic LC matrix, the temperature dependences of the electro-conductivity have been investigated. The charge currier mobility and activation energy in cells were estimated. The mechanism of high-velocity resonance nonlinearity due to the saturation of excited states in photosensitive centers and mechanisms of the grating erasure connected with charge transport in the ionic LC matrix were discussed. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121594 2006-01-01T00:00:00Z