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Using the method of the joint crystallization of solutions of nitrate salts with ultrasonic treatment, xerogels and highly dispersed mesoporous powders of the following composition are synthesized: (CeO2)1 – x(Nd2O3)x (x = 0.02; 0.05; 0.10), Gd1 – xSrxCo0.5O3 – δ (x = 0.1, 0.15, 0.2, 0, 25), Gd0.4Sr0.1Ni0.5O3 – δ, and Gd0.125La0.125Sr0.25Co0.5O3 – δ; and based on them, nanoceramic materials with a crystalline cubic structure of the fluorite type, as well as an orthorhombic and tetragonal structure of the perovskite type with CSR ~ 55–90 nm (1300°С), respectively, are obtained. The physicochemical properties of the resulting ceramics are studied; it is revealed that it has an open porosity of 7–11% for the composition (CeO2)1 – x(Nd2O3)x and 17–42% for materials with the Gd1 – xSrxCo0.5O3 – δ, Gd0.4Sr0.1Ni0.5O3 – δ, and Gd0.125La0.125Sr0.25Co0.5O3 – δ composition. Materials based on cerium oxide predominantly have the ionic (ion transport numbers ti = 0.71–0.89 in the range 300–700°С) type of electrical conductivity due to the formation of mobile oxygen vacancies in the heterovalent substitution of Ce4+ by Nd3+; and σ700°С = 0.31 × 10–2 S/cm Solid solutions based on nickelate and lanthanum cobaltite have mixed electron-ionic conductivity, σ700°С = 0.59 × 10–1 S/cm with transfer numbers te = 0.92–0.99 and ti = 0.08–0.01. The prospects for using the obtained ceramic materials as solid oxide electrolytes and electrodes for medium-temperature fuel cells (FCs) are shown. [ABSTRACT FROM AUTHOR]

Finely dispersed mesoporous powders of the following composition are synthesized by the method of cocrystallization of nitrate salts with ultrasonic treatment: La1–xSrxNiO3–δ, La1–xSrxCoO3–δ, and La1–xSrxFe0.7Ni0.3O3–δ (x = 0.30; 0.40). Based on them, ceramic nanomaterials of the given composition with a coherent scattering region (CSR) of ~65–69 nm (1300°С) are obtained. Ceramics fired at 1300°C are single-phase and have a tetragonal and orthorhombic perovskite-type structure in the La2O3‒SrO‒Ni(Co,Fe)2O3–δ system. Solid solutions have mixed electron–ion conductivity with transfer numbers te = 0.98–0.90 and ti = 0.02–0.10. Ceramics with a tetragonal perovskite-type crystal structure exhibit higher electrical conductivity than materials having an orthorhombic perovskite-type crystal structure. According to their electrophysical properties related to the structural features of solid solutions, ceramic materials obtained based on them are promising as solid oxide cathodes for average-temperature fuel cells. [ABSTRACT FROM AUTHOR]

Nanopowders of BaHfO3 and BaZrO3, are synthesized by the cocrystallization of nitric acid salts. Ceramic materials based on them with a crystalline cubic structure of the perovskite type, grain size 70–75 nm, and open porosity 8–10% are obtained. The mechanisms of proton electrical conductivity and the pathways of hydrogen migration in ceramic materials of the BaHfO3 and BaZrO3 composition are studied using the theoretical calculations: computer modeling by the method of the electron density functional and the sum of the valence forces. The energy parameters characterizing the behavior of hydrogen in these materials are determined. It is revealed that proton conduction occurs in two stages: rotation around the oxygen ion and intraoctahedral proton transfer between neighboring oxygen ions. The studies carried out show that the use of the obtained ceramic materials is promising as proton-conducting solid electrolytes in hydrogen power engineering. [ABSTRACT FROM AUTHOR]

Nanocrystalline ceramic samples of the ZrO2–3 mol % Y2O3 composition with varying degrees of tetragonality c/a (1.4337 and 1.0425) are obtained. The process of the low-temperature degradation of ceramics is studied by the methods of X-ray phase analysis and electron microscopy. It is found that samples with a high degree of tetragonality are more resistant to the action of a humid environment, while the phase composition in the bulk of the samples remains practically unchanged and the transformation t-ZrO2 → m-ZrO2 occurs mainly in the surface layers without significantly affecting the mechanical properties of the ceramics. [ABSTRACT FROM AUTHOR]

In this study, the electron density functional theory method is used to obtain maps of the electron density distribution for a monolayer TiS3. The adsorption of H2 on the surface of a monolayer TiS3 decorated with Mg cations is studied. The adsorption energy is –0.156 eV/molecule, which is a fairly high value, and allows us to consider this material as promising for creating hydrogen storage devices. [ABSTRACT FROM AUTHOR]

The effects of oceanic and biotopic factors on the size and age at maturity of sea urchins Strongylocentrotus intermedius alongside the northwestern coast of Primorsky krai are discussed. The growth rate and body size of the sea urchin at 50% maturity of the population corresponds to 30–35 mm in clusters with high growth rates and to 20–22 mm in clusters with low growth rates. In populations inhabiting southern areas of northern Primorsky krai, S. intermedius reaches final maturity at 40–45 mm, while in areas further to the north, at 26–30 and 31–35 mm. The age at final maturity in areas between Ezhovaya Bight and Cape Khitrovo and along Cape Nadezhdy was 4+ to 5+, while in other areas it was 3+. We argue that the differences in sizes and time periods in which maturity is reached in various S. intermedius populations depend on the local environment within the studied coastal area, primarily, on the abundance of available food, rather than on latitudinal zoning. [ABSTRACT FROM AUTHOR]

Using the liquid-phase methods of synthesis—the coprecipitation of hydroxides and the hydrothermal method—mesoporous xerogels are obtained based on the ZrО2-Y2О3-CeО2 system with 5-8-nm particles and powders (after the heat treatment of xerogels at 600°C) with a coherent scattering region (CSR) size of 9 to 10 nm and Ssp = 96-156 m2/g. After calcination at 1400°C, the powders are transformed into tetragonal solid solutions with a CSR size of 65 nm in the synthesis by the coprecipitation method, and they are transformed into solid solutions with a CSR size of 84 nm with a high degree of tetragonality of c/a = 1.438-1.431 in the synthesis by the hydrothermal method. [ABSTRACT FROM AUTHOR]

Nanopowders with a composition of (СeO2)1-x(Gd2O3)x (x = 0.03, 0.05, 0.07, and 0.10) are synthesized by the coprecipitation method using cryotechnologies. The coherent scattering region (CSR) of the powders is 10-14 nm and the specific surface area is 70-81 m2/g. Based on the powders, ceramic nanosized materials with CRS of 64-71 nm are obtained. The dependence of the phase composition, microstructure, and electrical transport properties of the obtained samples on the Gd2O3 content is established. In a CeO2-Gd2O3 system, a solid solution with the composition of (CeO2)0.90(Gd2O3)0.10 has the highest ionic conductivity with the transfer number of ions of ti = 0.74 at a temperature of 700°C. It is shown that ceramics of this composition can be used as a solid electrolyte of intermediate-temperature fuel cells due to their physicochemical characteristics. [ABSTRACT FROM AUTHOR]

Precursor powders in the ZrO2–HfO2–Y2O3–CeO2, In2O3–ZrO2, and NiO–Nd2O3 systems for components of solid oxide fuel cells have been prepared by liquid-phase synthesis. We have determined formation conditions and the particle size of ZrO2- and In2O3-based solid solutions and neodymium nickelate (Nd2NiO4), demonstrated the feasibility of producing nanocrystalline powders (10–30 nm) of tailored chemical composition in the temperature range 500–900°C, and optimized powder consolidation conditions. Nanoceramics with a crystallite size from 60 to 90 nm have been obtained and their microstructure and phase composition have been investigated. We have studied the electrical properties of the ZrO2- and In2O3-based solid solutions and the Nd2NiO4 compound and established the range of their electrical conductivity at temperatures from 300 to 1000°C: 2.27 × 10–3 to 2.51 S/cm for the ZrO2-based solid solution, 8.91 × 101 to 6.59 × 103 S/cm for the In2O3-based solid solution, and 3.98 × 102 to 5.02 × 102 S/cm for Nd2NiO4. [ABSTRACT FROM AUTHOR]

The sexual cycle of Japanese mitten crab Eriocheir japonica (de Haan, 1835) in its northern range in water bodies of the Primorye proved to have specific properties including changed seasonal dynamics of gonad maturity stages, delayed spawning period, and reduced breeding season. The ovary color regularly changed during the gonad growth in females, which was accompanied by an increase in total carotenoid content from 1.4 to 22.2 mg/100 g tissue and by changes in the proportion of major pigments. The relative content of the carotene fraction notably decreased and that of astaxanthin slightly decreased during gonad maturation. The revealed changes in carotenoid levels in the ovary point to the activity and significance of pigment metabolism in the reproductive cycle of E. japonica. [ABSTRACT FROM AUTHOR]

Powders–precursors of a tetragonal solid solution based on partially stabilized zirconium dioxide (t-ZrO2) and aluminum-magnesium spinel (MgAl2O4) are synthesized using the method of the cocrystallization of solutions of nitrate salts from which nanocrystalline (<100 nm) composite materials are fabricated at 1400°C in the ZrO2(Y2O3)–MgAl2O4 system with an open porosity of 3%. The structure, physical–mechanical properties, and thermal stability of the nanocomposites are investigated. It is established that the introduction of MgAl2O4 into the matrix of the solid t-ZrO2 solution increases the thermal resistance of the ceramics under the thermal cycling conditions (20–1000°С). The effect of thermal cycling on the phase composition, hardness, and bending strength of the ceramics in the ZrO2(Y2O3)–MgAl2O4 system is investigated. [ABSTRACT FROM AUTHOR]

The electron structure of Li2MnSiO4 and Li2FeSiO4 in a layered orthorhombic crystal structure of Pmn21 is studied by the electron density functional method. Using the analysis of the density of crystal orbital Hamilton populations (COHPs), the features of chemical bond formation in these substances are studied. Anisotropy of the chemical bond of Mn with oxygen atoms is observed for Li2MnSiO4 with the complete extraction of lithium atoms from the structure. The formation of anisotropy of the chemical bond can indicate that Mn is trying to change the coordination and the beginning of the restructuring of the compound structure and its reduced stability. [ABSTRACT FROM AUTHOR]

The phase composition and electrical properties of HfO[sub 2]-YO[sub 1.5]-PrO[sub 1.5] systems have been determined. Studies have been made to identify how the specific electrical properties of these solid solutions are influenced by praseodymium oxide additives when the yttrium oxide content is constant, and how they are influenced by the interchangeability of praseodymium oxide with yttrium oxide when the hafnium dioxide content is kept constant. [ABSTRACT FROM AUTHOR]

The adsorption of TiO nanoclusters onto a TiS2 single layer surface is investigated via the density functional theory in combination with random structure searching algorithms. The nanoclusters are Ti—O dipoles and their orientation in the electrostatic field is induced by S atoms near the TiS2 single layer surface. The binding energy of nanoclusters with a TiS2 single layer surface is found to be 4.713 eV. Another curious observation is the creation of a nanocluster with an S–S–S–O anionic tetrahedron by Ti atoms, where the O anion is located at the maximum distance from the surface. [ABSTRACT FROM AUTHOR]

A synthetic study was carried out to assess the average external exposure dose accumulated over the entire period of employment by nuclear workers as a world professional category (1946–2010). The average (mean) and median doses for a sample of 63 variants (18 countries; cohorts of various nuclear installations, including international groups) were 31.1 and 24.0 mSv, respectively. The values after processing the sample for outliers (up to 52 variants) decreased to 21.7 and 20.7 mSv. Whatever values are taken into account, they are below the limit of low doses of radiation with low LET (up to 0.1 Gy/Sv) and, on average for the group, should not lead to any tissue (deterministic) effects. Estimation of the cancer mortality rate at the doses received in terms of excess relative risk (ERR) per 1 Gy (based, for example, on the value for a pooled cohort of 15 countries) [Cardis et al., 2005] gave values that cannot be detected against the background of carcinogenic effects of nonradiation factors, confounders, and biases. Thus, the expected increase in the number of deaths from cancer over ten years was only 0.036–0.06% of the size of the study group. The obtained values of the average doses for nuclear workers were compared with those for medical radiologists (combined values for studies from seven countries; mainly the 1950s and up to 2000), which amounted to 62.9 and 61.9 mSv for the mean and median, respectively. The average dose received for medical radiologists is thus 2–3 times higher than that for nuclear workers. Although the contribution of incorporated radionuclides to the radiation dose for the second group was not considered, the discovered fact can have an effect on the formation of a relatively favorable image of employment in the nuclear power industry. [ABSTRACT FROM AUTHOR]

Precursor powders in the ZrO-CeO-ScO-AlO system have been prepared using the sol-gel method. A physicochemical analysis of the synthesized ceramics, single crystals, and nanofilms based on ZrO and HfO oxides has been performed. It has been revealed that the introduction of alumina AlO into the ZrO-based ceramic samples reduces the thermal expansion coefficient and that these ceramic materials possess a high electrical conductivity as compared to the other materials under investigation. [ABSTRACT FROM AUTHOR]

Nanofilms based on zirconia and ceria have been synthesized using the electron-beam evaporation method. It has been established that their composition involves a tetragonal solid solution based on zirconia and weakly crystallized α-Al2O3 (corundum). The quantitative information concerning the morphology of oxide nanofilms has been obtained. It has been revealed that the films have a developed surface. The prepared films can be proposed for the use as resistive sensor chips intended for determining PO 2 in different media. [ABSTRACT FROM AUTHOR]

Methods of coprecipitation of hydroxides in the bulk and in a microreactor with counterswirling flows are used to obtain mesoporous nanodispersed xerogels based on zirconium dioxide. The features of the morphology and state of the surface of the obtained xerogels are studied. It is shown that the investigated method of obtaining nanosized xerogels based on zirconium dioxide in counterswirling flows makes it possible to reduce the degree of particle agglomeration. [ABSTRACT FROM AUTHOR]

Xerogels in the ZrO2–Y2O3–CeO2 system are obtained by coprecipitation. The influence of the synthesis method on the acid-base xerogel surface properties are studied. The sinuous dependence of the Lewis and Brønsted site content on the particle surface on the conditioning time of precipitates in the mother liquor and the presence of subsequent low-temperature processing is established. The relationship is established between the resulting ceramics properties, precipitate processing conditions, and the functional xerogel structure. [ABSTRACT FROM AUTHOR]

A strong highly porous ceramic for endoprosthesis possessing open porosity and elasticity modulus values similar to those of bone tissue is prepared through the solid-phase sintering of specimens of the initial powders of the (ZrO2)0.97(Y2O3)0.03 and [(ZrO2)0.97(Y2O3)0.03]0.8(Al2O3)0.2 compositions with blowing agents. The dependence of the characteristics of the sintered ceramics on the composition of zirconium-containing powders and blowing agents is investigated. [ABSTRACT FROM AUTHOR]