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The enhancement of the functional properties of materials at reduced dimensions is crucial for continuous advancements in nanoelectronic applications. Here, we report that the scale reduction leads to the emergence of an important functional property, ferroelectricity, challenging the long-standing notion that ferroelectricity is inevitably suppressed at the scale of a few nanometers. A combination of theoretical calculations, electrical measurements, and structural analyses provides evidence of room-temperature ferroelectricity in strain-free epitaxial nanometer-thick films of otherwise nonferroelectric strontium titanate (SrTiO3). We show that electrically induced alignment of naturally existing polar nanoregions is responsible for the appearance of a stable net ferroelectric polarization in these films. This finding can be useful for the development of low-dimensional material systems with enhanced functional properties relevant to emerging nanoelectronic devices.

This study aims to determine the thermophysical properties of industrial uranium-gadolinium oxide fuel pellets containing 3.35, 5, and 8 wt % Gd 2 O 3 in order to evaluate the performance and safety of VVER-type reactor fuels. The obtained experimental data included thermal expansion, specific heat capacity at constant pressure, and thermal diffusivity. In addition, the temperature dependence of thermal conductivity was calculated up to 1900 K for fuels with varying Gd 2 O 3 content. Figures: 5; Tables: 6; References: 12.

Local forms of the sandy sculpin ( Leocottus kesslerii (Dybowski 1874)), formed in Lake Baikal and Arakhlei and Gusinoe lakes, were studied. The studies demonstrated the existence of differences between the lake forms according to the following traits of external morphology. In the Baikal form, the head width is greater than the length; in the Arakhlei and Gusinoe forms, the head width is less than its length. In the Baikal and Gusinoe forms, there is a gap between the dorsal fins; it is absent in the Arakhlei form, in which the dorsal fins come into contact with each other. In the Arakhlei form, the anal fin is long (37.4–43.0%, on average, 39.3% SL); in the Baikal form, the A base length reaches 29.0–34.5% (on average, 32.9% SL). In the Baikal and Arakhlei forms, there are small and sparse bone prickleson the body; they are large and dense in the Gusinoe form. The detected differences demonstrate a low level of morphological isolation of the forms. More significant differences are demonstrated by the ecological indices: growth rate, nutrition spectra, peculiarities of reproduction, and absolute fecundity values. Differences in ecological indices are caused by the adaptation of the sandy sculpin forms to the specific conditions of the lakes in which they live. The study of genetic differentiation was carried out by the control region of mtDNA. The sandy sculpin forms had a weak genetic isolation. The average p -distances between the L. kesslerii forms varied from 0.33 ± 0.12 to 0.51 ± 0.24%. These values of the genetic distances are within the limits of intraspecific variability. The data obtained on the morphological, ecological, and genetic differentiation of the lake forms of the sandy sculpin demonstrated that fish from Lake Baikal and Arakhlei and Gusinoe lakes belong to the nominative subspecies Leocottus kesslerii kesslerii .

The initial and final melting temperatures of standard, optimized, and modernized zirconium alloy of the E110 type were determined. The stability of zirconium alloys both in terms of composition and phase state during high-temperature heating was secured by preventing contact interaction between the experimental samples and tooling materials. The following melting temperature of the investigated alloys was obtained with maximum error 0.5%: solidus 2116–2121 K, liquidus 2126–2133 K. It was found that iron and oxygen impurities do not affect the melting temperature of the investigated alloys.

— Svyatonosites, which are intermediate moderately alkaline to alkaline andradite rocks, were found for the first time on the Svyatoi Nos Peninsula at the beginning of the 20th century. One of the discussible questions is related to their age, which has not precisely been determined by isotopic methods. The results of U/Pb dating of accessory zircon from svyatonosites and leucosyenite showed the Late Paleozoic age for the Markov (310‒297 Ma) and Eskola (317‒312 Ma) plutons of the Svyatoi Nos Peninsula, which is synchronous with the formation of granitoids of the Barguzin complex (330‒290 Ma). Zircon from leucosyenite of the Markov pluton has a typical magmatic structure, which is in agreement with a Th/U ratio of >0.3. Anhedral zircon grains from svaytonosites together with the Th/U ratio of <0.1 indicates the recrystallization processes at the origination stage of the Markov and Eskola plutons. The slightly older 40 Ar/ 39 Ar age of amphibole from svyatonosites of the Markov pluton (360‒336 Ma) is related to the presence of excessive 40 Ar, which can be sourced from the Early Paleozoic metamorphic rocks.

The microalgae Tetraselmis suecica is widely studied as a potential producer of triglycerides for biofuels production and number of biologically active substances. Artificial cultivation of microalgae is associated with its use as live food for bivalve molluscs cultivation, sea cucumbers and fish. The efficiency of microalgae cultivation depends on many environmental factors and is an economically demanding process. The use of exogenous stimulants - phytohormones, has a significant effect on the growth and cultivated microalgae biochemical parameters. It was shown that salicylic acid in concentrations of 1.0 - 3.8 x 10-8 M stimulated the growth of the Tetraselmis suecica culture. In comparison with the control, the growth of the culture by 415% was noted, with the addition of phytohormone at a concentration of 3.8 x 10-8 M. Under the influence of salicylic acid, the amount of protein increased 3.2 times, protein 1.3 times, and the synthesis of carbohydrates was suppressed. The caloric content of Tetraselmis suecica was determined by biochemical composition differences, which must be taken into account when determining the cultivation strategy for marine invertebrates, since a certain plastic material is required for each stage of metamorphosis. The toxicity of salicylic acid due to its accumulation in the environment is well known. The results obtained in our work will contribute to the expansion of knowledge about the effect of acid on microalgae and the potential for their use for wastewater bioremediation.

Corrosion resistance of U 3 Si 2 in water vapor is insufficient and increases due to fragmentation caused by formation of the hydride phase. In the present work, samples of triuranium disilicide were tested in an autoclave chamber in the water vapor medium from 350 to 600°C in the presence of a zirconium alloy which is an efficient hydrogen absorber. The dependence of the corrosion rate on the temperature was considered. The order of formation of oxide layers was revealed.

The results of an investigation of the density, microstructure, thermophysical properties, and melting point of uranium-molybdenum pellets produced by powder metallurgy are reported. The obtained results were compared with similar data for uranium-molybdenum ingots. The properties of uranium-molybdenum pellets fabricated by powder metallurgy are shown to be in good agreement with the properties of ingots obtained by casting.

An engineering model for sintering of fuel pellets is presented. The model is based on a previous, fully developed, mathematical model, which was implemented by the method of finite volumes, for the process of heat-and-mass transfer of a fuel pellet with arbitrary arrangement in the sintering drawing boat. The main task of the engineering model was to accurately simulate the sintering process for fuel pellets in industrial furnaces with different numbers and types of heating zones. The program implementing the numerical calculations had to be undemanding in terms of computing resources and work stably on average (in terms of parameters) personal computers.

Selection criteria based on density and uranium capacity are presented for fuel to be used in accident-tolerant fuel rods. The optimal composition of the uranium-molybdenum alloy is proposed based on studies and experience in working on the development of uranium alloys. Two technological schemes for producing fuel pellets are considered: melting and casting. The technology of forming pellets by the powder method is also considered. The results of a study of the physical and mechanical characteristics of cast and sintered fuel pellets in confirmation of their compliance with the specified criteria are presented.