Наукова спадщина О.О. Русова в контексті актуальних проблем української етнології

У лютому виповнилося 160 років з дня народження відомого вченого, етнографа, статистика та громадського діяча Олександра Русова.This article is devoted to the famous scholar, ethnographer, civil activist Oleksandr Rusov. All his work was concentrated on the study of Ukrainian folk, their history, life style and language. Among his most prominent works was the foundation of the statistics as the scholarly discipline and its use for the ethnographical studies. Special attention deserves his work “The Statistics of the Ukrainian Population of the European Russia”. His data on Ukrainian and Russian population in various regions at different historical times are very valuable for the contemporary scholars. He actively participated in Ukrainian cultural life: he was the organizer of the first Ukrainian plays on Kyiv stages, the editor of Prague edition of “Kobzar”, and participated in different social and cultural organizations

Нелинейная нетерова краевая задача в критическом случае

Знайдено необхiднi та достатнi умови iснування розв’язкiв слабко нелiнiйної нетерової крайової задачi для системи звичайних диференцiальних рiвнянь у критичному випадку.We construct necessary and sufficient conditions for the existence of the solution of a Noether weakly nonlinear boundary-value problem for a system of ordinary differential equations in the critical case

Using a Neural Network to Improve the Optical Absorption in Halide Perovskite Layers Containing Core-Shells Silver Nanoparticles

Core-shells metallic nanoparticles have the advantage of possessing two plasmon resonances, one in the visible and one in the infrared part of the spectrum. This special property is used in this work to enhance the efficiency of thin film solar cells by improving the optical absorption at both wavelength ranges simultaneously by using a neural network. Although many thin-film solar cell compositions can benefit from such a design, in this work, different silver core-shell configurations were explored inside a Halide Perovskite (CH\u2083NH\u2083PbI\u2083) thin film. Because the number of potential configurations is infinite, only a limited number of finite difference time domain (FDTD) simulations were performed. A neural network was then trained with the simulation results to find the core-shells configurations with optimal optical absorption across different wavelength ranges. This demonstrates that core-shells nanoparticles can make an important contribution to improving solar cell performance and that neural networks can be used to find optimal results in such nanophotonic systems

Optical response of silver nanoneedles on a mirror

Plasmonic properties of metal nanostructures are appealing due to their potential to enhance photovoltaics or sensing performance. Our aim was to identify the plasmonic characteristics of silver nanoneedles on a reflective layer in the polarized optical response. Experimental ellipsometry results are complemented by finite-difference time-domain (FDTD) calculations. Plasmon resonances on the nanoneedles can indeed be observed in the polarized optical response. This study reveals the details of the complex antenna-like behaviour of the nanoneedles which gives an agreement between experiment and FDTD simulation. The simulations show that the plasmon resonances lead to an effective negative refractive index, originating from the negative refractive index of the nanoneedles in combination with its supporting substrate, i.e. a mirror. This original study of a complex plasmonic system by ellipsometry and FDTD has great relevance for applications, making use of intricate light matter interaction

Задачи глобальной экологии

Changes in the size distribution and composition of bimetallic Pd-Au nanoclusters have been observed after hydrogen exposure. This effect is caused by hydrogen-induced Ostwald ripening whereby the hydrogen reduces the binding energy of the cluster atoms leading to their detachment from the cluster. The composition changes due to a difference in mobility of the detached palladium and gold atoms on the surface. Fast palladium atoms contribute to the formation of larger nanoclusters, while the slower gold atoms are confined to the smaller nanoclusters. These transformations in the Pd-Au nanocluster size and composition set a limit for chemical reactions in which such nanoclusters are involved together with hydrogen

Multipole plasmons and their disappearance in few-nanometre silver nanoparticles

Electron energy-loss spectroscopy can be used for detailed spatial and spectral characterization of optical excitations in metal nanoparticles. In previous electron energy-loss experiments on silver nanoparticles with radii smaller than 20 nm, only the dipolar surface plasmon resonance was assumed to play a role. Here, applying electron energy-loss spectroscopy to individual silver nanoparticles encapsulated in silicon nitride, we observe besides the usual dipole resonance an additional surface plasmon resonance corresponding to higher angular momenta for nanoparticle radii as small as 4 nm. We study the radius and electron beam impact position dependence of both resonances separately. For particles smaller than 4 nm in radius the higher-order surface plasmon mode disappears, in agreement with generalized non-local optical response theory, while the dipole resonance blueshift exceeds our theoretical predictions. Unlike in optical spectra, multipole surface plasmons are important in electron energy-loss spectra even of ultrasmall metallic nanoparticles

Проблемы медицинского обслуживания моряков в Украине

Стаття присвячена деяким проблемам медичного обслуговування моряків в Україні, в тому числі питанням професійних оглядів, які визначають придатність моряка по стану здоров‘я до роботи на суднах. Розглядаються проекти пропозицій до наказу, який готується і який буде регламентувати медичні огляди моряків.The article is devoted some problems of medical service of seafarers in Ukraine, in particular to the questions of professional examinations, determining the fitness of seafarer to be fit for work on ships. The projects of appendixes are examined to the preparing order, to regulating physical examinations of seafarers

Драматичні елементи у фольклорі – традиція та актуальність

The researches of the folklore and ethnographic sources underscore, that the dramatic elements exist in the folk art (songs, fairy tales, small folklore genres, children folklore etc.), in customs and in the other forms of the life of the folk. But it's importaint what I mean by the notion "dramatic elements in the folklore". Namely, existence of the action, plot, culmination and denouement, then the place and time of the development of the action, monologue, dialogue in the action, characters, masks, dresses, text, scenography, scenario, director, audience, puppet-show, i. e. the presence of the performance. In this paper special attention is given to some dramatic acting with multitude of the dramatic elements, which are connected with large quantity of the Cristmas holidays. We also drew parallels between traditional forms and new elements of celebration and results of the actualization of some innovations in society. It is worth to refer the carnivals in Vechani and Strumitsa and also celebrations of the Eve in Skopje

Luminescent tracks of high-energy photoemitted electrons accelerated by plasmonic fields

The emission of an electron from a metal nanostructure under illumination and its subsequent acceleration in a plasmonic field forms a platform to extend these phenomena to deposited nanoparticles, which can be studied by state-of-the-art confocal microscopy combined with femtosecond optical excitation. The emitted and accelerated electrons leave defect tracks in the immersion oil, which can be revealed by thermoluminescence. These photographic tracks are read out with the confocal microscope and have a maximum length of about 80 \u3bcm, which corresponds to a kinetic energy of about 100 keV. This energy is consistent with the energy provided by the intense laser pulse combined with plasmonic local field enhancement. The results are discussed within the context of the rescattering model by which electrons acquire more energy. The visualization of electron tracks originating from plasmonic field enhancement around a gold nanoparticle opens a new way to study with confocal microscopy both the plasmonic properties of metal nano objects as well as high energy electron interaction with matter

3D-printed external light trap for solar cells

We present a universally applicable 3D-printed external light trap for enhanced absorption in solar cells. The macroscopic external light trap is placed at the sun-facing surface of the solar cell and retro-reflects the light that would otherwise escape. The light trap consists of a reflective parabolic concentrator placed on top of a reflective cage. Upon placement of the light trap, an improvement of 15% of both the photocurrent and the power conversion efficiency in a thin-film nanocrystalline silicon (nc-Si:H) solar cell is measured. The trapped light traverses the solar cell several times within the reflective cage thereby increasing the total absorption in the cell. Consequently, the trap reduces optical losses and enhances the absorption over the entire spectrum. The components of the light trap are 3D printed and made of smoothened, silver-coated thermoplastic. In contrast to conventional light trapping methods, external light trapping leaves the material quality and the electrical properties of the solar cell unaffected. To explain the theoretical operation of the external light trap, we introduce a model that predicts the absorption enhancement in the solar cell by the external light trap. The corresponding calculated path length enhancement shows good agreement with the empirically derived value from the opto-electrical data of the solar cell. Moreover, we analyze the influence of the angle of incidence on the parasitic absorptance to obtain full understanding of the trap performance