Effects of different levels of UV-B radiation on marine epilithic communities: a short-term microcosm study

Epilithic communities from brackish coastal water of the east coast of Sweden were studied in order to reveal their responses to different levels of UV-B radiation. The experiment was conducted for seven days in an indoor microcosm system. The epilithic communities were exposed daily to different doses of UV-B radiation: 1, 3, 5 and 7 hours, respectively. The intensity of the UV-B radiation used was similar to that in natural environments. After seven days clear shifts both in species composition and community structure were observed. All species of diatoms showed negative correlation with enhanced levels of UV-B. On the other hand, abundance of cyanobacteria was positively correlated with enhanced levels of UV-B (Calothrix aeruginea, R=0.49;Oscillatoria amphibia, R=0.93; Pseudanabaena mucicola, R=0.26). Communities dominated by diatoms and green algae at the initial stage of the experiment did show a drastic decrease in diatom abundance under UV-B stress and finally became dominated by cyanobacteria. Among green algae the abundance of Cladophora sericea correlated positively (R=0.33) with enhanced exposure to UV-B, while Monoraphidium-species exhibited negative correlation to UV-B. Otherwise, no significant correlation between other green algae species identified and UV-B stress could be detected. We conclude that UV-B radiation, even at lower levels, is capable to induce severe changes to marine epilithic communities. The trends revealed in the present study predict a shift from communities dominated by diatoms and green algae to those dominated by cyanobacteria.No disponibl

Circular photon drag effect in bulk tellurium

The circular photon drag effect is observed in a bulk semiconductor. The photocurrent caused by a transfer of both translational and angular momenta of light to charge carriers is detected in tellurium in the mid-infrared frequency range. Dependencies of the photocurrent on the light polarization and on the incidence angle agree with the symmetry analysis of the circular photon drag effect. Microscopic models of the effect are developed for both intra- and inter-subband optical absorption in the valence band of tellurium. The shift contribution to the circular photon drag current is calculated. An observed decrease of the circular photon drag current with increase of the photon energy is explained by the theory for inter-subband optical transitions. Theoretical estimates of the circular photon drag current agree with the experimental data.Comment: 8 pages, 4 figure

Studying of the 9Be Structure

Experimental data on inelasti

One-step fabrication of protonic ceramic fuel cells using a convenient tape calendering method

The present paper reports the preparation of multilayer protonic ceramic fuel cells (PCFCs) using a single sintering step. The success of this fabrication approach is due to two main factors: the rational choice of chemically and mechanically compatible components, as well as the selection of a convenient preparation (tape calendering) method. The PCFCs prepared in this manner consisted of a 30 μm BaCe0.5Zr0.3Dy0.2O3-δ (BCZD) electrolyte layer, a 500 μm Ni-BCZD supporting electrode layer and a 20 μm functional Pr1.9Ba0.1NiO4+δ (PBN)-BCZD cathode layer. These layers were jointly co-fired at 1350 °C for 5 h to reach excellent gas-tightness of the electrolyte and porous structures for the supported and functional electrodes. The adequate fuel cell performance of this PCFC design (400 mW cm-2 at 600 °C) demonstrates that the tape calendering method compares well with such conventional laboratory PCFC preparation techniques such as co-pressing and tape-casting. © 2020 by the authors.Russian Foundation for Basic Research, RFBR: 18-38-20063This work was supported by the Russian Foundation for Basic Research, grant number 18-38-20063. The authors thank G. Vdovin for his assistance in experiments. The SEM characterisation was carried out at the Shared Access Centre "Composition of Compounds" of the Institute of High-Temperature Electrochemistry [51]

The application of statistical methods in the development of Cyrillic-Latin converter for Tatar language

The article describes the process of a software product development that allows you to convert a text written in Tatar to Latin using Cyrillic graphics. The aspects of Cyrillicgraphics to Latin graphics conversion are considered for Tatar language. The authors study the application of various statistical methods necessary for converter operation and analyzethe speed and the accuracy of the conversion algorithms. An algorithm was created and software modules were developed that made it possible to convert messages written in Tatar Cyrillic alphabet to Tatar Latin alphabet. Based on normative documents and scientific works on the use of Latin graphics in Tatar language, a verbal and an algorithmic model of conversion was constructed. In the process of development, it turned out that the process of a Tatar word conversion depends on its origin. If native Tatar words are converted according to the phonetic principle (кәлам - qäläm), the borrowed words are converted according to the rules of transliteration. The main problem of the study is the problem of a word origin determination. In order to solve this problem, the authors propose various algorithms. Software tools based on the statistical processing of linguistic data are considered and developed in the work: combined bigram analysis, naive Bayesian classification and a direct search. Each of these algorithms is used to determine the etymology of a word, on which depends the application of certain rules of conversion from Cyrillic to Latin. The result of the research is a developed software product that is capable to carry out the process of Cyrillic graphics conversion to Latin for Tatar. In the future, the authors plan to improve the software product and use it in educational activities