A brief review of theoretical models describing the dislocation mechanisms of misfit stress relaxation in crystalline nanoheterostructures of lower dimension, such as composite nanoparticles, nanowires, and nanolayers is presented. The critical conditions for the appearance of the first misfit dislocations in such nanoheterostructures are determined. The equilibrium distribution density was calculated for the circular prismatic loops of misfit dislocations in core–shell nanowires and proved to be in good agreement with the results of experimental observations. Energy barriers have been found for the nucleation of misfit dislocations in composite nanowires with a core shaped as a rectangular prism and in composite nanolayers with long prismatic inclusions. The lowest barriers are shown to occur upon the emission of partial or perfect dislocation dipoles by the edges of inclusions, depending on the characteristic dimensions of a heterostructure. The directions of further studies in this area were proposed.

We have studied Si mass transport and morphological transformations on the Si(111) surface during (√3 × √3)-Sn reconstruction formation and following Si homoepitaxy in 600–825°C interval by in situ ultrahigh vacuum reflection electron microscopy (UHV REM) and ex situ atomic force microscopy (AFM). We have shown that the formation of a metallic α-(√3 × √3)-Sn phase during Sn deposition at T < 650 °С leads to Si 2D island nucleation on > 1 μm terraces, while the formation of a mosaic γ-(√3 × √3)-Sn phase at T > 650 °С is followed by monatomic step shift in the step-up direction and provides Sn/Si(111) interface with wide atomically flat terraces. The step shift value has been measured as functions of substrate temperature and Sn deposition rate to determine emitted by the steps Si coverage participating in γ-phase formation. The electromigration-induced drift of disordered “1 × 1”-Sn domains has been shown to entail enhanced noncompensated Si mass transport followed by the Si(111)-(√3 × √3)-Sn surface roughening. The kinetics of 2D island nucleation and growth near monatomic steps and on wide (up to 10 μm) terraces on the Si(111)-γ-(√3 × √3)-Sn surface during Si deposition at 700°C is limited by surface diffusion only, and critical nucleus i consists of ∼ 20–100 Si atoms.

Climate changes have led to an increase in fire rates throughout the entire range of larch (Larix sibirica, L. gmelinii, and L. cajanderi). We have tested the hypothesis that natural fires are an important factor that contributes to the functional stability and dominance of larch forests in the continuous permafrost zone. We include satellite imageries, on-ground survey data, dendrochronological measurements, and ecoclimatic variables in our analysis. We find that warming in the 21st century has led to an increase in the intensity and frequency of fires and moderate and extreme (>10 000 ha) burned areas. The maximal burn areas and fire frequency are observed in the northern and southern parts of the permafrost zone, respectively. The frequency of fires and burned areas are inversely exponentially dependent on precipitation, soil and ground cover moisture, and atmospheric drought, and they increase exponentially with an increase in air temperature. In the zone of continuous permafrost, larch successfully regenerates in burned areas (up to 500 000+/ha of seedlings). In the zone of island permafrost (the southern part of the study area), the number of regeneration is 2–3 orders lower, and regeneration is represented mainly by hardwood species. The increasing fire frequency in the south of the larch range contributes to the partial transformation of the forested areas into grass and shrub communities. There is a high probability that larch will retreat from its southern range during the process of continuous permafrost thawing. Gross primary productivity (GPP) in burned areas quickly (3–15 years) recovers to the prefire level. In combination with increasing GPP trends, that indicates that larch forests retain their function as a carbon sink despite the increasing fire rate. Under conditions of an increase in fire rate, the firefighting strategy must be changed. It is necessary to realize (1) the impossibility of the total suppression of fires and (2) the ecological significance of fires in the larch forests in the cryolithozone, in which fires are the most important factor supporting the health and dominance of larch forests. Alongside that, periodic natural fires reduce the likelihood of catastrophic fires. It is necessary to focus firefighting efforts on the areas of the most important social, natural, and economic importance, while controlling burning outside these areas by monitoring methods.

Изменения климата повлекли возрастание горимости во всем ареале лиственницы (Larix sibirica, L. gmelinii, L. cajanderi). В работе рассматривается гипотеза о роли пожаров как важного природного фактора, способствующего функциональной устойчивости и доминированию лиственничников в криолитозоне. Исследования проводились в ареале лиственницы в криолитозоне. Анализировались спутниковые снимки, данные наземных обследований и дендрохронологических измерений, эколого-климатические переменные. Установлено, что потепление в 21-м столетии повлекло увеличение интенсивности и частоты пожаров, средней и экстремальной (>10,000 га) площади гарей. Максимальные площади и частоты пожаров наблюдаются на севере и юге криолитозоны. Частота и площадь пожаров связаны обратными экспоненциальными зависимостями с осадками, влажностью почв и напочвенного покрова, атмосферной засушливостью, экспоненциально возрастая с повышением температуры воздуха. В зоне сплошной мерзлоты лиственница успешно возобновляется на гарях (до 500+ тыс./га сеянцев). В зоне островной мерзлоты (южная часть ареала) численность естественного возобновления на 2-3 порядка ниже, и возобновление представлено преимущественно мелколиственными породами. Возрастающая горимость на юге ареала лиственницы способствует трансформации лесных земель в травяно-кустарниковые сообщества. В процессе таяния многолетней мерзлоты высока вероятность сокращения зоны доминирования лиственницы в южной части ее ареала. Валовая первичная продуктивность (GPP) на гарях восстанавливается до предшествующего пожару уровня в течение 3-15 лет, что в сочетании с преимущественно возрастающими трендами GPP указывает на сохранение лиственничниками функции стока углерода несмотря на возрастающую горимость. В условиях возрастающей горимости требуются изменения в стратегии борьбы с пожарами. Необходимо осознать невозможность подавления всех пожаров и экологическую значимость пожаров в лиственничниках криолитозоны, где они представляют важнейший фактор сохранения лиственничников, а также снижают вероятность развития катастрофических пожаров. Важно сфокусировать борьбу с пожарами на территориях с приоритетной социальной, природной и экономической значимостью, контролируя пожары вне указанных территорий методами мониторинга. Climate changes have led to an increase in fire rates throughout the entire range of larch (Larix sibirica, L. gmelinii, L. cajanderi). We tested the hypothesis that natural fires are an important factor that contributes to the functional stability and dominance of larch forests in the continuous permafrost zone. We included satellite imageries, on-ground surveys data, dendrochronological measurements and eco-climatic variables into analysis. We found that warming in the 21st century has led to an increase in the intensity and frequency of fires, moderate and extreme (>10,000 ha) burnt areas. The maximal burn areas and fire frequency observed in the northern and southern parts of the permafrost zone, respectively. The frequency of fires and burned areas are inverse exponentially dependent on precipitation, soil and ground cover moisture and atmospheric drought, and increase exponentially with air temperature increase. In the zone of continuous permafrost, larch successfully regenerates in burnt areas (up to 500+ thousand/ha of seedlings). In the zone of discontinues permafrost (southern part of the study area) the number of regeneration is 2-3 orders lower and regeneration represented mainly by hardwood species. The increasing fire frequency in the south of the larch range contributes to the partly transformation of the forested areas into grass and shrub communities. There is a high probability of larch retreat from its southern range during the process of continuous permafrost thawing. Gross primary productivity (GPP) in burned areas quickly (3-15 years) recovers to the pre-fire level. In combination with increasing GPP trends, that indicates carbon- sink role of larch forests increasing fire rate. In conditions of fire rate increase, it necessary to change firefighting strategy. It is necessary to realize (1) the impossibility of the total fires’ suppression and (2) the ecological significance of fires in the larch forests in cryolithozone, in which fires are the most important factor of supporting larch forests health and dominance. Alongside with that, periodic natural fires reduce the likelihood of catastrophic fires. It is necessary to focus the firefighting on the areas of the priority social, natural and economic importance, controlling burning outside these areas by monitoring methods.

Recently we have studied the concentration N-2D of 2D Ge island nucleated on large-scale Si(111)-(7 x 7) terraces at 550 - 650 degrees C as function of the substrate temperature T and Ge deposition rate R [J. Cryst. Growth. 531 (2020) 125347], where we have shown that N-2D ( R ) dependence is characterized by a power law with scaling exponent chi = 1 +/- 0.1. However, in the frames of classical Venables rate-equation approach, the obtained range of chi values do not allow one to unambiguously determine the critical nucleus size i , since chi = 1 +/- 0.1 can be attributed to both diffusion limited (DL) and attachment limited (AL) growth regimes. In order to determine an exact i size and growth kinetics, in this work, we have investigated the scaled capture-zone distribution (CZD) of nucleated 2D Ge islands on the same Ge/Si(111)-(7 x 7) samples and described it by the generalized Wigner distribution P-beta = a(beta)A(beta)exp(-b(beta)A(2)), where P-beta is the probability density of getting into some region of capture zone values, A is normalized Voronoi cell area for 2D island, beta=i/chi is scaling parameter directly related to the critical nucleus size i . It has been shown that the kinetics of 2D Ge island nucleation on the wide Si(111)-(7 x 7) terraces at elevated temperatures should procced under AL growth kinetics with i = 3-5 particles.

The morphology and magnetic properties as well as adsorption capacity and catalytic activity of Fe 3 O 4 -Ag nanoparticles synthesized by the solvothermal method were studied in dependence on the duration of the thermolysis process (3, 6, and 8 h). X-ray diffraction, transmission electron microscopy, and energy -dispersive spectroscopy measurements showed that the morphology of nanoparticles changed strongly as the duration of thermolysis increased. At 6 and 8 h duration, Fe 3 O 4 nanocrystals grow and assemble into porous spherical globules with an Ag core (samples 2 and 3). These samples demonstrate high magnetization value and very low coercivity. The adsorption capacity of nanoparticles was studied with respect to two organic dyes: cationic methylene blue (MB) and anionic Congo red (CR). The particles showed preferential adsorption of the cationic dye. High catalytic activity towards four dyes: MB, methyl orange (MO), CR, and Rhodamine C (RhC) at the presence of NaBH 4 is the remarkable property of these samples. The rate constant of the catalytic reaction was 1.4 min -1 . Simultaneous exposure of CR and MO dyes to nanoparticles and NaBH 4 caused their irreversible 100 % degradation while in the case of MB and RhC, a transition to their leuco form occurred.

Changes in the hydrothermal regime of soils caused by the melting of the permafrost layer are the most important ecological factor in the dynamics of vegetation in the cryolithozone. The impact of soil thawing on the growth index (GI) of larch (Larix spp.) and on the gross and net primary productivity (GPP and NPP) of vegetation in the Arctic region of Central Siberia (sparse forests, tundra, and forest tundra) is investigated. The following hypotheses are tested: (1) gravimetric data allow us to assess the dynamics of water mass in soils; (2) thawing of frozen soils stimulates the growth of woody plants and the productivity of vegetation. This work uses methods of dendrochronology, field data, satellite gravimetry (GRACE survey), and remote sensing of GPP (Terra/MODIS survey). An analysis of gravimetric data has revealed a significant long-term trend of decreasing water mass in soils of the cryolithozone (R2 = 0.68). The amount of water released during melting is estimated at 6.4 ± 2.3 kg/m–2 per year. A close relationship was established between the GI of larch and GPP with moisture anomalies in soils (r = –0.7 and r = –0.9, respectively). The increasing temperature of the root zone and the deficit of water vapor moisture also have a positive effect on the GI of larch and the GPP value of vegetation as a whole (r = 0.6 and r = 0.6–0.9, respectively). It is established that pyrogenic carbon losses are significantly (two orders of magnitude) lower than the NPP value. Under conditions of waterlogged soils, which are typical for the Arctic, climate warming is accompanied by an improvement in the hydrothermal growth regime of the plant cover and contributes to an increase in the productivity of vegetation and the preservation of the cryolithozone status of a carbon sink area.

Climate change increases the frequency of forest fires throughout the entire boreal zone. This paper examines the long-term wildfire dynamics in pine forests of Central Siberia, relationships between environmental and climatic variables on the one hand and the occurrence frequency of fires and size of burnt forest areas on the other, and the postfire dynamics of vegetation cover productivity. A coupled analysis of ground survey data, remote sensing data (spectroradiometric and gravimetric information collected by the Terra/MODIS and GRACE satellites), and dendroecological data is performed. In the period from the 18th to the 20th century, fire return intervals decreased from 33 to 20–25 years. No statistically significant trends in fire occurrence frequency were identified in the current century; however, catastrophic (i.e., affecting more than 1 million ha) fires were observed in its second decade, and both the number of fires and size of burnt areas have significantly increased (by 3.5 and 3.0 times, respectively). The frequency of fires and size of burnt areas closely correlate with wetting and temperature conditions in the prefire period. Furthermore, fire statistics parameters correlate with wetting conditions (precipitation amount, moisture content in the ground cover and soil, and the Self-Calibrated Palmer Drought Severity Index (sc-PDSI)) stronger than with air temperature. It is shown that equivalent water thickness values obtained using gravimetric methods can be used in fire risk assessments. High correlation levels were identified between the growth index of pine trees and vegetation cover productivity indices (i.e., gross primary productivity (GPP) and net primary productivity (NPP)) generated based on remote sensing data. The results indicate that these indices can be used to estimate forest stand productivity dynamics. The vegetation cover productivity and the radial growth index of pine trees in burnt areas quickly (within a decade) restore to prefire values, which indicates that northern pine forests retain their carbon sequestration function despite climate change and the increasing frequency of fires.

Electrochemical behavior of hybrid electrodes with electroactive coatings based on activated IR-pyrolyzed polyacrylonitrile as well as hybrid polymer-carbon composites with activated IR-pyrolyzed polyacrylonitrile (porous N-doped carbon component) and poly(diphenylamine-2-carboxylic acid) (polymer component) has been investigated for the first time in a lithium-organic electrolyte (1 M LiClO4 in propylene carbonate). Electrochemical behavior of the coatings has been investigated at a smooth glass carbon surface and at flexible strips of anodized graphite foil with developed porous loosened surface. Specific electrochemical capacity of the hybrid electrodes has been found dependent on the conditions of the composite coating synthesis. The influence of heat treatment on the electrochemical behavior of the activated IR-pyrolyzed polyacrylonitrile–poly(diphenylamine-2-carboxylic acid) composites has been investigated. Heat-resistant electroactive coatings have been obtained for the first time under conditions of IR heating of the IR-pyrolyzed polyacrylonitrile–poly(diphenylamine-2-carboxylic acid) composites, specific capacity of which in a lithium aprotic electrolyte has been 0.107–0.114 F/cm2, only 17

•Sn-induced structural transitions on Si(111) at 200–860 °C have been first visualized.•γ-√3-Sn reconstruction formation atT > 650 °C induces step shift.•Sn surface electromigration entails √3-Sn⇔“1 × 1”-Sn phase transitions.•Sn adatoms have a positive effective charge being ≥ 0.001∙e.•Activation energy of Sn atom desorption from “1 × 1”-Sn layer is 2.5 ± 0.1 eV.

Hydroxyapatite, a mineral of the apatite group, has an important and useful property. It has the propensity for various kinds of substitutions, which allows modification of its properties and expansion of the possibilities of applying the synthetic material. The properties of a synthesized substance depend on the way it is produced, as the synthesis conditions influence the structural and morphological characteristics of the particles being formed. This work shows that, in the case of mechanochemical synthesis with the introduction of iron cations as a dopant, the structure of hydroxyapatite, in which the dopant occupies the position of the calcium cation, is formed. This type of substitution is accompanied by a decrease in the lattice parameters of the hydroxyapatite. It is shown that iron cations predominantly possess a 3+ charge, which is independent of the charge of the initial reagent containing the iron cation. It is also found that in the process of mechanochemical synthesis under certain conditions, the simultaneous partial replacement of calcium cations with iron cations and phosphate groups with carbonate group can be implemented. The powders obtained by mechanochemical synthesis are characterized by powder diffraction, infrared spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), and Mössbauer spectroscopy.

Разработаны составы сорбционных материалов на основе гидрофосфатов оксотитана(IV), модифицированные катионами циркония(IV) и содержащие одновременно катионообменные, представленные НРО \(_{4}^{{2 - }}\) -группами, и анионообменные, представленные ОН – -группами, функциональные центры. Проведена апробация полученных образцов при сорбции катионов/анионов сурьмы(III) из высокосолевого раствора. Показано, что сродство ионообменной матрицы к ионам сурьмы(III) усиливается с повышением содержания в ее составе функциональных групп. Такие составы могут рассматриваться как перспективные ионообменные материалы для эффективного извлечения радионуклидов сурьмы из многокомпонентных высокосолевых жидких радиоактивных отходов.

— We have proposed compositions of titanyl hydrogen phosphate-based sorption materials modified with zirconium(IV) cations and containing both cation and anion exchange functional centers, represented by НРО _4^2 - and OH – groups, respectively. The synthesized materials were tested in sorption of antimony(III) cations and anions from high-salt solutions. Increasing the concentration of functional groups in ion exchange matrices has been shown to increase their affinity for antimony(III) ions. Such compositions can be regarded as promising ion exchange materials for efficient extraction of antimony radionuclides from multicomponent high-salt liquid radioactive waste.

Using in situ ultrahigh vacuum reflection electron microscopy, we have studied structural transitions on the Si (1 1 1) surface induced by Sn deposition up to 2 ML coverage (1 ML = 7.8 center dot 10(14) cm(-2)) and by Sn desorption at substrate temperatures T = 200-860 degrees C. We have shown that Si-Sn intermixing in the adsorption layer during Sn deposition onto the Si(1 1 1)-(7 x 7) surface at T > 650 degrees C leads to the shift of the monatomic steps in the step-up direction, and there is formed a mosaic (root 3x root 3)-Sn phase. The electromigration of Sn adatoms induced by DC resistive heating has been shown to redistribute adsorbed Sn layer and to cause local (root 3x root 3)-Sn double left right arrow "1 x 1"-Sn structural transitions on the surface. We have estimated the lower bound of the Sn adatom positive effective charge on the Si(1 1 1) surface q(eff)(Sn) >= 0.001 center dot e. During AC annealing, the rate of desorption-induced "1 x 1"-Sn domain area shrinkage has been measured as a function of substrate temperature, and the activation energy of Sn adatom desorption has been estimated to be 2.5 +/- 0.1 eV.

This article presents the results of a comparative analysis of the radial increment of various larch species and provenances growing on a common ecological background in experimental forestry established in 1965–1967 on the Krasnoyarsk forest steppe by employees of the Sukachev Institute of Forest, Siberian Branch, Russian Academy of Sciences. The provenances of Siberian larch ( Larix sibiric a Ledeb.) from different elevation belts of the Southern Siberian Mountains, Gmelin larch ( L. gmelinii Rupr.) from the Trans-Baikal and Zeya provinces (Eastern Siberia), and Japanese larch ( L. leptolepis Gord) introduced from the island of Sakhalin are studied. Based on the cluster analysis of radial increment series, four groups of provenances are identified with different growth strategies, depending on the response to environmental factors: mountain–forest steppe and mountain–taiga provenances of Siberian larch and provenances of Gmelin larch from Transbaikalia. The provenance of Japanese larch from Sakhalin has formed a separate cluster. The highest values of radial increment are found in groups of mountain–forest-steppe provenances formed by Siberian larch and Gmelin larch trees introduced from East Siberian provinces. Low values of radial increment are noted in provenances of Siberian larch trees from Southern Siberia mountain–taiga zone and Japanese larch from Sakhalin. Dendroclimatic analysis is used to identify the relationship between the environmental variables of the introduction zone and the radial increment of the studied provenances. In the Krasnoyarsk forest steppe, the main factor limiting radial increment is the moisture content of the root layer in the middle of the growing season (July–August). Larch trees introduced from wetter habitats respond more strongly to an increase in water stress, while the radial increment of trees taken from drier habitats responds positively to an increase in the length of the growing season.

Using a model solution, we have demonstrated the feasibility of using titanium(IV) oxyhydroxyphosphate-based ion-exchange materials for extraction of Cs+ and Sr2+ cations from multicomponent high-salt bottom residues. Conditions for the use of the ion exchangers have been optimized experimentally: liquid : solid = 50, t = 25°C. It has been shown that Cs+ is effectively extracted at pH 2, whereas Sr2+, at pH 8. The zirconium-modified sorbent has been shown to have a higher affinity for metal cations. The modified sorbent is especially selective for cesium in the acid pH region owing to the higher mobility of the protons of its hydrogen phosphate groups in comparison with the unmodified sorbent composition.