The formation of highly dispersed zinc oxide powder during combustion of zinc nitrate with glycine mixture and its application for photocatalytic phenol decomposition

The paper presents the results of a detailed study of the process and products of combustion during self-propagating high-temperature synthesis (SHS) of ZnO zinc oxide powder from mixtures of such common reagents as oxidizer zinc nitrate and reducing agent (fuel) glycine, as well as the application of synthesized highly dispersed submicron and nanosized ZnO powder for the phenol photocatalytic decomposition under the action of ultraviolet irradiation. An aqueous solution of a mixture of reagents (the SHS-S process or Solution Combustion Synthesis – SCS) and the gel from a mixture of initial dry reagents formed when they were moistened due to hygroscopicity (the SHS-G process or Gel Combustion Synthesis – GCS) were combusted. The authors studied the phase and chemical compositions, the structure of the combustion product, and the effect of calcination in an oxidizing air medium and grinding in drum ball and planetary-centrifugal mills, as well as in mortar, on them and their photocatalythic activity. The study showed that calcination considerably increases the photocatalytic activity of combustion products due to a significant decrease in carbon impurity in the unburned fuel remains, and grinding in mills reduces the photocatalytic activity due to iron contamination and coarsening of ZnO particle agglomerates. The difference between the photocatalytic activity of the SHS-G and SHS-S products in the phenol decomposition is evident only at the initial stage of ultraviolet irradiation, after which this difference disappears. The authors discuss the direction of further research to increase significantly the photocatalytic activity of zinc oxide synthesized during combustion to use it effectively for the phenol decomposition under the action of visible light

ТОЛКОВАНИЕ ПОНЯТИЯ, ИМЕНУЕМОГО «ЗАДАЧА ПРЕДСТАВЛЕНИЯ ЗНАНИЙ»

In this article the definition of the term «the problem of representation of knowledge» isformed, which orients towards creation the technology, allowing to transfer practice of the solution of this problem by the developerof each concrete system, based on knowledge, from realization heuristics to realizationof results of theoretical researches. Also the authors point out the directions of improvement of the basic theory for this technology.В статье сформировано толкование понятия «задача представления знаний», ориентированное на создание технологии, позволяющей перевести практику решения этой задачи разработчиком каждой конкретной системы, основанной на знаниях, из реализации эвристик в ракурс реализации результатов теоретических исследований. А так же указаны направлениясовершенствованиябазовой теории для этой технологии

Chiral photonic super-crystals based on helical van der Waals homostructures

Chirality is probably the most mysterious among all symmetry transformations. Very readily broken in biological systems, it is practically absent in naturally occurring inorganic materials and is very challenging to create artificially. Chiral optical wavefronts are often used for the identification, control and discrimination of left- and right-handed biological and other molecules. Thus, it is crucially important to create materials capable of chiral interaction with light, which would allow one to assign arbitrary chiral properties to a light field. In this paper, we utilized van der Waals technology to assemble helical homostructures with chiral properties (e. g. circular dichroism). Because of the large range of van der Waals materials available such helical homostructures can be assigned with very flexible optical properties. We demonstrate our approach by creating helical homostructures based on multilayer As$_2$S$_3$, which offers the most pronounced chiral properties even in thin structures due to its strong biaxial optically anisotropy. Our work showcases that the chirality of an electromagnetic system may emerge at an intermediate level between the molecular and the mesoscopic one due to the tailored arrangement of non-chiral layers of van der Waals crystals and without additional patterning

Exploring van der Waals materials with high anisotropy: geometrical and optical approaches

The emergence of van der Waals (vdW) materials resulted in the discovery of their giant optical, mechanical, and electronic anisotropic properties, immediately enabling countless novel phenomena and applications. Such success inspired an intensive search for the highest possible anisotropic properties among vdW materials. Furthermore, the identification of the most promising among the huge family of vdW materials is a challenging quest requiring innovative approaches. Here, we suggest an easy-to-use method for such a survey based on the crystallographic geometrical perspective of vdW materials followed by their optical characterization. Using our approach, we found As2S3 as a highly anisotropic vdW material. It demonstrates rare giant in-plane optical anisotropy, high refractive index and transparency in the visible range, overcoming the century-long record set by rutile. Given these benefits, As2S3 opens a pathway towards next-generation nanophotonics as demonstrated by an ultrathin true zero-order quarter-waveplate that combines classical and the Fabry-Perot optical phase accumulations. Hence, our approach provides an effective and easy-to-use method to find vdW materials with the utmost anisotropic properties.Comment: 11 pages, 5 figure

Features of creating wear-resistant anti-corrosion coatings with a barrier layer on fragments of fuel claddings from E110 o.ch.

Results of the development of protective chromium-containing coatings based on the FeCrNi and CrNi systems for fuel claddings within framework of the accident tolerant fuel (ATF) are presented in this paper. Coatings were deposited by the outer surface of cladding tubes fragments from E110 o.ch. alloy (sponge-based Zr-1%Nb) up to 500 mm length by complex ion-plasma treatment on ILUR-03 and KVK-10 installations. The results of the control tests carried out in high-temperature steam at the GAZPAR bench at 1200 °C up to 400 s showed that Cr-FeCrNi-Cr and Cr-CrNi-Cr coatings reduce total oxygen penetration into the alloy from 144 to 98 and 55 ?m, respectively and Cr-CrNi-Cr coatings with a Mo barrier layer completely block the diffusion of oxygen into the material

INTERPRETATION OF CONCEPT, CALLED AS “THE PROBLEM OF REPRESENTATION OF KNOWLEDGE”

In this article the definition of the term «the problem of representation of knowledge» isformed, which orients towards creation the technology, allowing to transfer practice of the solution of this problem by the developerof each concrete system, based on knowledge, from realization heuristics to realizationof results of theoretical researches. Also the authors point out the directions of improvement of the basic theory for this technology

The First Data on Harpacticoid Copepod Diversity of the Deep-Water Zone of Lake Baikal (Siberia, Russia)

Lake Baikal (LB) is the only freshwater ancient lake on Earth where animals inhabit all bathymetric zones down to the deepest sites (approximately 1640 m). However, there is very little data on the composition of their abyssal harpacticoid fauna. On the basis of the samples collected in LB in 2010–2017 at a depth of 270–1632 m, analysis of the fauna composition and species diversity of harpacticoids in the deep-water zone is presented. Studies were conducted in all parts of the lake, including areas of a hydrothermal, oil–methane seeps, and mud volcanoes. Nineteen Baikal endemic morphological species of the genera Bryocamptus, Attheyella, and Moraria (Baikalomoraria) were found. A brief description of the taxa morphology is presented. The genus Bryocamptus was the richest by species number at the studied sites, and Bryocamptus smirnovi Borutzky was the most frequent. The most diverse (8 species) was the fauna of the Saint Petersburg methane seep. Studies have shown that the taxonomic diversity of harpacticoid copepods in the deep-water zone of LB is lower than in its littoral zone. According to two non-parametric species estimators (Chao 2 and Jackknife 1), a 1.5-fold increase of species richness of harpacticoids of the LB abyssal is expected

ELABORATION AND APPLICATION OF THE DIAGNOSTIC INDEX BASED ON MULTIVARIATE ANALYSIS OF BIOMARKERS TO DETERMINE THE ACTIVITY OF RHEUMATOID ARTHRITIS

Rheumatoid arthritis (RA) is a heterogeneous disease. The pathogenesis of this disease is based on a complex combination of genetically determined and acquired defects of the regulatory mechanisms that limit the pathological activation of the immune system in response to potentially pathogenic stimuli and often to physiologic stimuli. Modern antirheumatic drugs can effectively suppress the inflammatory process and largely deter the disease progression. However, their potential can be fully used only provided that the appropriate treatment strategy is applied, with regular monitoring of disease activity being the key component in the management of RA patients. Quantitative assessment of the patient's status allows one to develop standardized indications for antirheumatic therapy. Application of clinical indices for assessment of the disease activity does not guarantee complete objectivity of the results. Diagnostic indices based on multivariate analysis of biomarkers are being elaborated. Accumulation of the data on features of protein profile in RA patients gave grounds for elaborating an index to determine disease activity. This index is based on measuring concentration of biomarkers associated both with clinical indices and their components (multibiomarker disease activity, MBDA) – VECTRA DA. MBDA is currently the only clinically proven laboratory index that can be used to monitor RA activity and to predict the progression degree of destructive joint disease and therapy effectiveness