http://repository.enu.kz/handle/enu/10466 Sat, 04 Apr 2026 03:30:35 GMT 2026-04-04T03:30:35Z http://repository.enu.kz/handle/enu/10598 Study of influence of mobile phone irradiation to tooth enamel EPR spectra Zhumadilov, K.Sh.; Ivannikov, A.I.; Stepanenko, V.F.; Hoshi, M. The contribution of mobile phones influence on electron spin resonance (EPR) spectra formation and electromagnetic noise signal for accuracy of dose estimation on example of tooth enamel samples measurements was investigated for low dose range. The spectra of irradiated tooth enamel samples in doses from 0 to 500 mGy have been measured. The spectra have been processed by mathematical fitting of model spectrum by least square methods. Standard deviation from nominal doses and uncertainty of dose estimation were determined. The noise level has been estimated in spectra by rest sum after model spectra fitting. Enamel samples were measured in 3 conditions: 1) during day from 9-17 o’clock; 2) during day from 9-17 o’clock with mobile phone. After 17 o’clock and in Saturday and Sunday from 9-17 o’clock (this suppose no any noise signal contributed to spectra). It was shown that the biggest uncertainty of dose estimation have been received in day time with mobile phone in on position. Standart deviation is decrising after 5PM with off mobile phone. Noise level in spectra measured after 5PM was less in comparison with spectra measured in day time. Sun, 01 Jan 2017 00:00:00 GMT http://repository.enu.kz/handle/enu/10598 2017-01-01T00:00:00Z http://repository.enu.kz/handle/enu/10596 SOFC: Prospects of development Kuterbekov, K.A.; Bekmyrza, K.Zh.; Nikonov, A.; Paranine, S.; Lipilin, A.; Baitassov, T.; Nygymanova, A. One of the main conditions for the transition to hydrogen energy is development of reliable, high-performance and cost-effective fuel cells, in which chemical energy is converted directly into electrical energy. The advantages of solid oxide fuel cells (SOFC) are: high electrical efficiency (50 - 60)%, in cogeneration with thermal energy the efficiency may reach 90%, and high operating temperatures (700 - 900 °C), which allows us to use practically any hydrocarbon fuel. Sun, 01 Jan 2017 00:00:00 GMT http://repository.enu.kz/handle/enu/10596 2017-01-01T00:00:00Z http://repository.enu.kz/handle/enu/10594 Ionizing radiation as a powerful tool for modification of metallic nanostructures Kadyrzhanov, K.K.; Kozlovskiy, A.L.; Mashentseva, A.A. This paper presents a case study of targeted modification of the structure and properties of zinc nanotubes ordered arrays by treatment with Xe +22 and Kr +17 swift heavy ions (SHI). Polyethylene terephthalate track-etched membranes (PET TeMs) with a pore density of (4 × 10 9 ) ions/cm 2 have been used as a template for electrochemical deposition of Zn. Scanning electron microscopy and energy dispersive analysis have been used for a comprehensive elucidation of the dimensionality, chemical composition of the synthesized samples. Dynamics of changes in the crystallite shape and orientation of NTs before and after irradiation has been studied by X-ray diffraction. Changes in conductive properties as a result of irradiation were discussed. After Xe +22 ions irradiation with a fluence of (1 × 10 11 ) m −2 or higher, the formation of loose areas in the structure of Zn NTs as a result of partial degradation of the crystal structure and, consequently, a decline in conductivity are observed. In case of Kr +17 ions, the increase in current conduction with the increase in fluence may be due to the increase in the current carriers. Sun, 01 Jan 2017 00:00:00 GMT http://repository.enu.kz/handle/enu/10594 2017-01-01T00:00:00Z http://repository.enu.kz/handle/enu/10593 Preparation and characterization of down-shifting film for silicon solar cell based on the stilben 420, PVA polymer and silver nanoparticles Mantel, A.; Irgibaeva, I.; Aldongarov, A.; Barashkov, N. 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. Sun, 01 Jan 2017 00:00:00 GMT http://repository.enu.kz/handle/enu/10593 2017-01-01T00:00:00Z