Role of the host polymer matrix in light emission processes in nano-CdS/poly vinyl alcohol composite

Participation of a polymericmedia in light-emitting processes of composite nano-CdS/polyvinyl alcohol is studied by probing different absorption-emission routes via adjustment of excitation wavelengths. It is shown that the polymeric constituent of the composite contributes chiefly to the photoluminescence excitation processes via absorption and excitation transfer to the embedded CdS nanoparticles while the composite emission occurs mostly within the nanoparticles.Financial support from the Swedish Institute via Visby program is greatly appreciated

Delay and distortion of slow light pulses by excitons in ZnO

Light pulses propagating through ZnO undergo distortions caused by both bound and free excitons. Numerous lines of bound excitons dissect the pulse and induce slowing of light around them, to the extend dependent on their nature. Exciton-polariton resonances determine the overall pulse delay and attenuation. The delay time of the higher-energy edge of a strongly curved light stripe approaches 1.6 ns at 3.374 eV with a 0.3 mm propagation length. Modelling the data of cw and time-of-flight spectroscopies has enabled us to determine the excitonic parameters, inherent for bulk ZnO. We reveal the restrictions on these parameters induced by the light attenuation, as well as a discrepancy between the parameters characterizing the surface and internal regions of the crystal.Comment: 4 pages, 4 figure

Сельскохозяйственное производство – основа продовольственной безопасности региона

Тез. докл. V Междунар. науч.-практ. конф., Гомель, 29–30 нояб. 2007 г

Excitonic parameters of GaN studied by time-of-flight spectroscopy

We refine excitonic parameters of bulk GaN by means of time-of-flight spectroscopy of light pulses propagating through crystals. The influence of elastic photon scattering is excluded by using the multiple reflections of the pulses from crystal boundaries. The shapes of these reflexes in the time-energy plane depict the variation of the group velocity induced by excitonic resonances. Modeling of the shapes, as well as other spectra, shows that a homogeneous width of the order of 10 \mu eV characterizes the exciton-polariton resonances within the crystal. The oscillator strength of A and B exciton-polaritons is determined as 0.0022 and 0.0016, respectively.Comment: 12 pages, 2 figure

Некоторые аспекты преподавания физиотерапевтических методов лечения на кафедре факультетской терапии

МЕТОДИКА ПРЕПОДАВАНИЯПРЕПОДАВАНИЕОБУЧЕНИЕ /МЕТОДЫФИЗИОТЕРАПИИ МЕТОДЫ /ОБУЧОБРАЗОВАНИЕ МЕДИЦИНСКОЕКАФЕДРА ФАКУЛЬТЕТСКОЙ ТЕРАПИИТЕРАПИЯ (ДИСЦИПЛИНА) /ОБУЧТЕХНОЛОГИЯ ОБУЧЕНИЯОБРАЗОВАНИЯ ТЕХНОЛОГИЯПЕДАГОГИЧЕСКИЕ ТЕХНОЛОГИ