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«Таким сотворил его Бог там, в его родном краю»: к юбилею академика РАН В. В. Наумкина
Full text linkК юбилею академика РАН В. В. Наумкин
Modeling the formation and growth of cubic sodium tungsten bronze during electrodeposition from a polytungstate melt
No full textThe experimental study of the formation/growth processes of crystals with Na0.74WO3 isostructural formula during potentiostatic electrolysis of 0.8Na2WO4–0.2WO3 and 0.9Na2WO4–0.1WO3 melts at 973 and 1023 K is performed. A mathematical model is proposed to describe the complex process mechanism, including the electroreduction of polytungstate anions [WnO3n+1]2– on the Pt cathode surface to [WnO3n]–, as well as the electrochemical and chemical reactions of Na+ with [WnO3n+1]2– and [WnO3n]–, respectively, on the crystal surface. The model considers the change in the concentration of lower reduced forms in the near-electrode layer, the ohmic drop in the melt, the mixed control of deposit growth, and the evolution of the new phase surface area and volume during the process. Exchange currents for electrochemical reactions, rate constants for reactions associated with deposit growth, surface concentration of lower reduced forms, formation time, and number density of nuclei are found from fitting chronoamperograms using this model. It is detected that the chemical reaction promotes the growth of crystals, while the electrochemical reaction leads to their electrodissolution under the studied conditions. The rates of forward and backward chemical reactions decrease as the temperature and the WO3 mole fraction in the melt decrease, respectively, while the kinetics of the electrochemical reaction depends weakly on these factors. The calculated crystal sizes and their numbers are in good agreement with the experimental ones. The proposed approaches to modeling are important for the development of technologies for the electrochemical synthesis of cubic NaxWO3
Integrating battery-like materials into supercapacitors
No full textA binder-free composite hybrid electrode material was deposited through electrodeposition by combining carbon-based materials (graphene oxide) and battery like materials (NiO, ZnO and Al2O3) in a single electrode. The structural, morphological and electrochemical properties of CaAl2O4–ZnO/rGO composite thin film were studied to characterize the hybrid composites. The average crystallite size D of the hybrid composites is 23 nm with an average inter planar spacing of 1.90 Å and lattice constants (a = b = c = 1.456 Å) that reveal a rhombohedral structure. The introduction of Ni increases the cracks and nullifies the rod-like morphology of the undoped thin film while the presence of Ag reveals the nonexistence of cracks at lower concentrations of Ag dopant but densely packed homogenous noodle-like grains with cracks can be seen at a 0.03 M sample. EDX analysis confirmed the presence of deposited elements with the exception of Ag, and this could possibly be due to the low intensity of the Ag dopant or the low deposition voltage. Cyclic voltammetry curves show typical electrochemical behavior with clear oxidation and reduction peaks for most samples. The Nix = 0.06 doped CaAl2O4–ZnO/rGO composite thin films have the maximum specific capacitance of 673 F/g at a scan rate of 100 mV/s, while the Agx = 0.03 doped thin film has the minimum specific capacitance of 205 F/g at the same scan rate. indicating that NCZr3 has a good electrochemical behavior at 0.1 mA/g with an energy density and a power density of 59.83 W · h/Kg and 26.926 W · h/Kg, respectively. These results reveal the suitability of the Ni doped material as an electrode material for supercapacitor applications and confirm the model of roughening. Further studies should be explored by lowering scan rates (5–50 mV/s), adding binder materials, and properly varying Ag concentration and deposition time in order to explore more desirable properties for advanced applications
Carbon nanofiber–based CuSn(OН)6 and CuSnO3 composites for NO2 gas sensors and supercapacitors
No full textCopper hydroxystannate, CuSn(OH)6, was obtained via a hydrothermal method from a mixture of solutions of copper(II) chloride and sodium stannate with the addition of sodium hydroxide solution until pH 10. The phase compositions of the hydrothermal synthesis and the thermal decomposition products were studied using thermal analysis, X-ray diffraction, scanning electron microscopy, and FTIR spectroscopy. It was established that at a synthesis temperature of 180 °C, a single-phase perovskite-like copper hydroxystannate is formed, with particles having cubic shapes measuring 35–38 nm (according to Scherrer’s equation). It was shown that the reaction of the CuSnO3/modified CNFs composite with NO2 at room temperature results in a 32% response at 2 ppm, whereas the response of the CuSn(OH)6/modified CNFs composite under the same conditions is 19%. The CuSnO3/modified CNF composite exhibits the best electrochemical characteristics compared to the CuSn(OH)6/modified CNF composite for use in supercapacitors. The composite material CuSnO3/modified CNFs demonstrated its applicability as an electrode material in supercapacitors, showing a specific capacitance of 288 F/g at a scan rate of 2 mV/s, compared to the CuSn(OH)6/modified CNFs (135 F/g). It was established that the specific capacitance of composites based on CNFs significantly exceeds that of single-phase copper stannates (14 and 6 F/g, respectively)
Critical metals and minerals of Kazakhstan and other central Asian countries: institutional barriers and strategic export policy
No full textRelevance. Central Asia holds vast reserves of critical metals and minerals such as lithium, nickel, aluminum, copper, uranium, and rare earth elements, offering strong potential for integration into global value chains. However, its resource-dependent export model and institutional barriers hinder investment and industrial processing. Kazakhstan, with the region’s largest resource base, plays a key role in shaping its critical metals and minerals strategy.Objective. The study aims to develop an evidence-based strategic framework for Kazakhstan’s export policy in critical metals and minerals, taking into account other Central Asian countries. It relies on comparative analysis, institutional assessment, and scenario-based forecasting.Methods and Data. The methodology combines time-series analysis of export dynamics using data from international trade databases (UN Comtrade and ITC Trade Map), forecasting for 2025–2027, a comparative institutional analysis of the models of Australia, Chile, and Kazakhstan, as well as an evaluation of regulatory quality based on international indices and analytical sources.Results. Modeling indicates a steady rise in Central Asian exports to Europe and Asia but also highlights structural imbalances and institutional barriers that hinder a transition from a resource-based model to sustainable development. Using Kazakhstan as a case study, the study proposes a framework emphasizing deeper processing, export diversification, and integration of environmental, social, and governance (ESG) standards.Conclusions. Central Asia holds strong potential to contribute to the global energy transition, with Kazakhstan best positioned to lead a long-term export strategy. The proposed framework combines national and regional perspectives to foster industrialization, attract investment, and strengthen the region’s role in the global economy
Spatial dependence of prices for seasonally demanded products across price segments in Russian regions
No full textRelevance. Since regional markets are interconnected and influence each other, forecasting price changes for goods and services requires considering both time and location. Economic instability, shifting supply chains, and rising inflation expectations make this research especially relevant. Additionally, the growing need for quick responses to price fluctuations highlights the importance of adopting data-processing methods that enable near real-time analysis.Research Objective. The aim of the study was to analyze the spatial dependence of prices and the presence of brands within the context of cyclically fluctuating demand and supply across different price segments.Data and methods. This study utilized data provided by the online analytics service продажи.рф, which encompasses daily selling (registered) prices for 135 ice-cream brands across 84 Russian regions, spanning the period from January 1, 2021, to December 31, 2023. The analysis examined regional differences in ice cream prices and brand representation, as well as the spatial autocorrelation of prices, particularly in relation to seasonal demand fluctuations. Spatial autocorrelation was assessed using global and local Moran’s I indices, with spatial clusters identified based on these estimates. To explore the cyclicality of spatial autocorrelation, partial autocorrelation functions (ACF and PACF) were used, and the Kruskal-Wallis test was applied.Results. The results of the analysis confirmed the differentiation of regions in terms of ice-cream brand representation, including variations across three price segments: Elite, Standard and Economy. We found a correlation between brand representation and regional population size, but no direct relationship with regional wage levels. Further analysis of individual brand prices and their spatial autocorrelation confirmed the hypothesized presence of spatial autocorrelation and demonstrated an increase in this autocorrelation over the study period. Examination of data cyclicality indicated that time series of average prices and global Moran’s I indices exhibited significant weekly cyclicality, while annual cyclicality was not consistently detected across all analytical methods and only emerged in the analysis of average prices. This suggests that seasonal variations in production and consumption volumes do not necessarily translate into corresponding seasonal fluctuations in prices or their spatial autocorrelation for all product groups.Conclusions. Spatial price dependence is not static; its level and dynamics are significantly influenced by product characteristics, underscoring the necessity of shifting from analyses of aggregate-price indices to analyses of individual product prices. A key methodological contribution of this study is the validation of findings previously observed with more aggregated data (year/month, product group) using highly detailed daily and brand-level data. This approach enhances forecasting accuracy by capturing the full scope of regional variations in consumer behavior
Топоним «пять Климатов» в контексте изучения ранней истории византийской фемы в Крыму
Full text linkThe Byzantine theme in the Crimea was established in 841 and was called the theme of the Klimata in official documents. It existed in this form for a short time and was transformed into the theme of Cherson in no later than 860. This name change reflects reduction of the theme’s territory in result of the complex military and political situation in the region and the limited resources of the Byzantine strategos. This article examines the meaning of the toponym “five Klimata” reading on one of the seals of its strategos. Its interpretation depends largely on the understanding of the term Klimata, which ninth- and tenth-century Byzantine sources used to designate Byzantine lands in the said region. Historiography presents different interpretations of the case. The first suggests that the Klimata refers exclusively to the territory of the Crimean Gothia, i. e. the Mountainous Crimea. Additionally, the Klimata were also the name of administrative districts of the Gothia, each having a central fort where the local archon resided. Among them were Cherson, Mangup, Eski-Kermen, Chufut-Kale, and Bakla, holding the status of archontiai within the theme of the Klimata. However, the above-said interpretation contradicts to the sources. In fact, the Byzantine Klimata in the Crimea referred to all the coastal and mountainous regions of the peninsula, from Cherson in the west to Bosporos in the east, which traditionally were in the sphere of political, economic, and ecclesiastical interests of the Byzantine Empire. The territorial limits and internal structure of the early Byzantine theme in the Crimea are best reflected by the toponym “five Klimata” which occurred on a mid-ninth-century seal and in the notitia from the age of Patriarch Nicholas I Mystikos, where are five archbishoprics of the Patriarchate of Constantinople on the peninsula: Cherson, Bosporos, Gothia, Sougdaia, and Phoulloi. Moreover, the internal administrative units of the theme of the Klimata should not be designated as archontiai or associated with the large forts known from archaeological records in the region. This specific administrative structure of the outlying provinces of Byzantium is represented in the Crimea only by the archontate of Cherson, which ceased to exist ca mid-ninth century.Византийская фема в Крыму была учреждена в 841 г. и в официальных документах получила название фемы Климатов. В таком виде она просуществовала недолго и не позднее 860 г. была трансформирована в фему Херсон. За сменой названия стоит процесс резкого сокращения территории фемы в связи со сложной военно-политической обстановкой в регионе и ограниченными ресурсами византийского стратига. В статье рассматривается содержание топонима «пять Климатов», представленного на одной из печатей ее стратига. Его интерпретация во многом зависит от понимания общего термина Климаты, которым в византийских источниках IX–X вв. обозначались византийские владения в регионе. В историографии существуют различные мнения по этому вопросу. Одно из них предполагает, что под Климатами подразумевается исключительно территория Крымской Готии, т. е. Горного Крыма. Кроме того, так назывались отдельные административные районы (дистрикты) Готии с центральными крепостями, где располагались резиденции местных архонтов. К ним относят крепости Херсон, Мангуп, Эски-Кермен, Чуфут-Кале и Бакла, имевшие статус архонтий в структуре фемы Климатов. Однако такие заключения противоречат данным источников. Византийскими Климатами в Крыму обозначались все приморские и горные области полуострова – от Херсона на западе до Боспора на востоке, которые традиционно составляли сферу политических, экономических и церковных интересов Византийской империи. Лучше всего территориальные пределы и внутренняя структура ранней византийской фемы в Крыму нашли отражение в топониме «пять Климатов», сохранившемся на печати середины IX в. и в данных нотиции времени патриарха Николая I Мистика, где зафиксированы пять христианских архиепископий Константинопольского патриархата на полуострове – Херсона, Боспора, Готии, Сугдеи и Фулл. Кроме того, все внутренние административные единицы фемы Климатов не следует обозначать архонтиями и пытаться соотнести их с известными по данным археологии крупными крепостями в регионе. Такая специфическая структура управления провинциями Византии в Крыму представлена лишь архонтатом Херсона, ликвидированным около середины IX в
Mechanosynthesis of 1,2,4-triazine-appended polyvinyl chloride (PVC) and studies of its fluorescence “turn-off” response to Fe3+
No full textIron plays crucial role in such important biochemical processes in the human body as the respiratory function. Both deficiency and excess of Fe3+/Fe2+ could induce serious diseases, including heart failure and diabetes. Additionally, iron is among essential micronutrient elements for the living organisms in the environment, as it is involved in plant metabolism, electron transport of photosynthesis and respiration, chlorophyll synthesis, nitrate reduction, and detoxification of reactive oxygen species. The methods and materials for the detection of Fe3+ /Fe2+ are of high demand. In this manuscript we wish to report a mechanochemical approach for the post-modification/functionalization of PVC with 3-(pyridyl-2)-1,2,4-triazine moieties to obtain a polymeric material for the visual detection of Fe3+/ Fe2+. The obtained polymer was characterized by means of 1H NMR- and IR-spectroscopy, as well as gel-penetration chromatography (GPC). Colorimetric and fluorescence “turn-off” response towards Fe2+ and Fe3+ in solution was investigated, and a Stern-Volmer constant as high as 0.1-0.3∙1o6 M–1 was observed for Fe3+
Колебание между эффектами значения и присутствия на границе эстетического измерения памяти о советском прошлом
No full textThe division into culture of meaning and culture of presence identified by H. U. Humbrecht’s division into the culture of meaning and the culture of presence became the starting point for theorising about aesthetic memorial aspects, which began in the works of H. G. Gadamer, F. R. Ankersmit, and H. White. To illustrate the interpenetration of cultures, the Soviet past was taken as a space of memory that has a socio-political impact on contemporary events and processes. The aesthetic dimension of the memory of the Soviet time covers a rather wide range of phenomena – from different types of art to everyday practices. On the one hand, anthropologists' attention to the materiality of late socialism, to objectification in the form of elements of experience testifies to the effect of presence; on the other hand, it is difficult to overestimate the importance that today is attached to the romanticisation and mythologisation of the Soviet. As a result of reference to the concept of post-memory, the phenomenon of nostalgia, contemporary Russian cinema, the study of social practices and rituals, and the analysis of media texts, conclusions are drawn about the significant share of the aesthetic in the memory of the Soviet past, which, in turn, acts as an indicator that allows us to diagnose the state of contemporary Russian society: whether it is dominated by the culture of meaning or presence, or whether there is a constant oscillation between the respective effects.Key words: culture of meaning, culture of presence, effect of presence, memory, Soviet past, aesthetic dimension of memory, post-memory, nostalgiaОбозначенное Х.-У. Гумбрехтом разделение на культуру значения и культуру присутствия стало отправным пунктом для теоретизирования относительно эстетических мемориальных аспектов, начатого в работах Х. Г. Гадамера, Ф. Р. Анкерсмита, Х. Уайта. Для иллюстрации взаимопроникновения культур было взято советское прошлое как пространство памяти, оказывающее социально-политическое влияние на современные события и процессы. Эстетическое измерение памяти о советском времени охватывает довольно широкий спектр феноменов – от разных видов искусств до повседневных практик. С одной стороны, внимание антропологов к материальности позднего социализма, к объектализации в виде элементов опыта свидетельствует об эффекте присутствия; с другой стороны, трудно переоценить то значение, которое сегодня придается романтизации, мифологизации советского. В результате обращения к концепту постпамяти, феномену ностальгии, к современному российскому кинематографу, изучению общественных практик и ритуалов, анализу медийных текстов делаются выводы о значимой доле эстетического в памяти о советском прошлом, которое, в свою очередь, выступает в качестве индикатора, позволяющего диагностировать состояние современного российского общества: доминирует ли в нем культура значения или присутствия или же происходит постоянное колебание между соответствующими эффектами.Ключевые слова: культура значения, культура присутствия, эффект присутствия, память, советское прошлое, эстетическое измерение памяти, постпамять, ностальги
Социальные противоречия в Южной Италии в конце V — первой половине VI в.
Full text linkThis article analyses the social contradictions in the Ostrogothic Kingdom, namely the interpretation of the causes and characteristics of crimes committed by rustics against merchants and large landowners, which took place in the Scylaceum region, as well as at the Lucanian fair of Marcelliana in the 530s. Based on the information obtained from Cassiodorus’ Variae, the author comes to the conclusion that during the period of late antiquity, the society of the southern regions of the Ostrogothic state was highly polarised. This was primarily due to the disappearance of the stratum of middle-class landowners and curiales, as well as the involvement of large landowners in commercial activities, which became an additional source of income for them. The economic split in society resulted in the growth of social tension in the south of Italy. Among the immediate reasons that prompted the rustics to act against the possessors, it is worth noting speculation in food products, tax fraud, and the fact that large landowners did not always effectively ensure the security of the territories under their control in the event of attacks by the Byzantines or Vandals. As a result, peasants who had lost their land plots, as well as former curiales, became robbers and resorted to robbing wealthy southerners. However, the author maintains that crimes of this kind were situational and represented a natural reaction against those in power by those who had lost their former social status and does not support the point of view that robberies were a manifestation of separatism in the society of the southern Italian regions. The author believes that the rustics in the analysed cases acted independently. As a result, the author concludes that social tension in the Ostrogothic state arose not only in connection with the forced coexistence of the Romans and Goths in one limited territory but could also be caused by economic processes taking place in the provinces. Статья посвящена анализу социальных противоречий в Остготском королевстве, а именно трактовке причин и особенностей преступлений рустиков против торговцев и крупных землевладельцев, которые происходили в районе Скилакия, а также на луканской ярмарке Марцеллиана в 530-е гг. Проанализировав сведения из Variae Кассиодора, автор приходит к заключению, что в период поздней Античности социум южных регионов Остготского государства был в высокой степени поляризован. Это было связано прежде всего с исчезновением слоя средних земельных собственников и куриалов, а также и с приобщением крупных земельных собственников к коммерческой деятельности, ставшей для них дополнительным источником дохода. Результатом поляризации общества стал рост социального напряжения на юге Италии. Среди непосредственных причин, побуждавших рустиков действовать против посессоров, стоит отметить спекуляцию продуктами питания, махинации с налогообложением и то, что крупные землевладельцы не всегда эффективно обеспечивали безопасность подконтрольных территорий от нападений византийцев или вандалов. В результате крестьяне, лишившиеся своих земельных участков, и бывшие куриалы становились разбойниками и грабили состоятельных южан. Автор считает, что преступления подобного рода были ситуативными и представляли собой естественную реакцию тех, кто утратил свой прежний социальный статус, и не поддерживает точку зрения о том, что грабежи стали проявлением сепаратизма социума южноиталийских регионов. Автор приходит к заключению, что социальная напряженность в Остготском государстве возникала не только из-за вынужденного сосуществования римлян и готов на одной ограниченной территории, но и была обусловлена экономическими процессами, происходившими в провинциях