Научный архив: статьи

В работе представлены синтез и характеристика композитных фотокатализаторов на основе g-C3N4, модифицированного Ni(OH)2 и Co(OH)2, для восстановления CO2 под действием видимого света (λ = 410 нм). Исследования методом РФА, УФ-вид спектроскопии и ПЭМ ВР показали, что осаждение гидроксидов не нарушает кристаллическую структуру g-C3N4, однако приводит к незначительному увеличению межслоевого расстояния и ширины запрещенной зоны. Ni(OH)2 представлен наночастицами размером около 7 нм, тогда как Co(OH)2 кристаллизуется в виде более крупных частиц размером ~24 нм. По данным ПЭМ установлено, что после фотокаталитического восстановления CO2 происходит частичная агломерация Ni(OH)2/NiO. Катализатор, содержащий 0,1 масс.% Ni(OH)2, продемонстрировал наибольшую фотокаталитическую активность - 7,04 мкмоль г-1 ч-1, что в 1,9 раза выше по сравнению с исходным g-C3N4. Для фотокатализатора 0,5 масс.% Co(OH)2/g-C3N4 наблюдалось увеличение активности в 1,3 раза относительно исходного g-C3N4. Полученное улучшение активности обусловлено формированием гетероперехода типа II между g-C3N4 и Ni(OH)2, что способствует эффективному переносу зарядов и подавлению их рекомбинации.

Since the introduction of Bitcoin in 2008, the size of the cryptocurrency market is becoming increasingly important for investors. Thus, the forecast of cryptocurrency price volatility is of particular interest to portfolio investors, as they are interested in accurately estimating the standard deviation of their portfolios to calculate the Value-at-Risk (VaR) as a risk measure for more optimal portfolio management. The HAR-RV model introduced by F. Corsi (in 2009) became more effective than the traditional GARCH type models in forecasting in the volatility of financial assets. In the last decade, cryptocurrencies started to dominate both the social media and the fi nancial press. At the same time, some academic papers use social media data to enhance the cryptocurrency volatility forecasting models. In our paper, we study how the use of Google Trends data could improve the precision of one-day-ahead of Bitcoin price volatility models forecasts. We use three different measures of the forecast precision. All models are estimated in rolling windows in order to control for possible structural breaks. Also, we estimate the optimal length of rolling windows to provide the best forecast precision on the historical Bitcoin price data from January 1, 2018 to December 31, 2022. We verify that the predictive power of the chosen model statistically differs from other models via MCS-tes

Предмет. Быстрый экономический рост Китая и других развивающихся стран привел к масштабной трансформации глобальной экономики и формированию нового центра силы, вокруг которого стали группироваться государства, заинтересованные в ликвидации финансово-экономической зависимости от США и их союзников. Стремясь сохранить свои лидирующие позиции, США спровоцировали обострение геополитической напряженности, что усилило фрагментацию мировой экономики (в настоящее время она проявляется в виде сосуществования двух основных блоков стран: G7 и БРИКС+) и мировых финансов. В статье представлен сравнительный анализ основных финансово-экономических индикаторов этих объединений. Цель исследования — определить текущее состояние и перспективы развития финансово-экономических потенциалов G7 и БРИКС+. Методы. На основе сравнительного и экономико-статистического анализа выявляются ключевые особенности развития экономики и финансов стран, являющихся членами указанных объединений. Сделан вывод о значительном финансово-экономическом потенциале БРИКС+. Кроме того, предлагается начать диалог между развитыми и развивающимися странами о формировании принципиально новой мировой финансово-экономической архитектуры.

Представлено обоснование выбранных схемных решений и описание процесса разработки GaAs-монолитно-интегральной схемы (МИС) для управляемого дискретного фазовращателя, предназначенного для работы в Ku-диапазоне частот. Данный фазовращатель может использоваться в приемопередающих модулях (ППМ) бортовой радиолокационной станции (РЛС) с активной фазированной антенной решеткой (АФАР), поскольку имеет 8 переключаемых состояний. Основное внимание в работе уделено схемотехническим решениям с интеграцией компонентов и оптимизацией характеристик фазовращателя, что обеспечивает высокую фазовую точность и низкие вносимые и возвратные потери разработанной микросхемы. Приведены результаты моделирования, подтверждающие соответствие фазовращателя заданным техническим требованиям. Дальнейшие этапы включают в себя производство и экспериментальное исследование разработанного устройства с преимуществом в количестве состояний фазового сдвига.

The drainage basin, river, and delta zone together constitute a complex open dipole system. In it, the watershed subsystem plays the role of an accumulator of high potential energy of water, the channel zones are cumulative transit zones of the potential energy of water, and the estuarine zones are dissipators of this energy, minimizing its level to the maximum. It is convenient to represent such a system as a “drainage” model, which allows us to consider all types of floods in its various sections and at the same time give a comparative assessment of the potential of river systems as dipole formations from tectonic positions.

В результате критического изучения коллекций Гербариев LE, MW, MHA, NSK, NS, AGBI, VLA в 2010– 2024 гг. во флоре Амурской области российского Дальнего Востока впервые выявлен вид Geranium turczaninovii (Serg.) Troshkina. Полученная информация дополняет сведения о современном распространении Geranium turczaninovii.

The perfect tense in Greek which is used to denote a state of affairs in the present as resulting from a past action does not find an exact equivalent in the system of Latin tenses: when faced with the need to express this idea a Latin speaker could either focus on the expression of the state by using the present tense (whereby the connection with the past was not expressed and would only be inferred), or use the perfect, in which case the effect of the past action on the present was not directly expressed and could only be deduced (the so-called resultative perfect). The article analyses Latin speakers’ attitude to this difference between Greek and Latin verbal systems, in particular, on the basis of the evidence collected from Roman epistolography when the letter-writer felt that the idea he wished to express could most aptly be rendered by a Greek perfect and switched to the Greek solely for that perfect form. The corpus of texts used for this study included the letters of Cicero to Atticus and his Epistulae ad Familiares, the Letters of Pliny the Younger, Seneca’s Letters to Lucilius, excerpts of Augustus’ letters preserved by Suetonius, and M. Cornelius Fronto’s correspondence with Marcus Aurelius

The present article offers a reassessment of Hom. ἄφρων [adj.] ‘unreasonable, senseless, foolish’, which is traditionally accounted for as an ablauting compound (of the type πατήρ: ἀπά- τωρ) based on the simplex φρένες [f. pl. tant.] ‘midriff, diaphragm’ (+Il.). This archaic ablauting pattern (viz. °φρων vs. simplex φρήν*) is totally unparalleled for body parts; besides, the Ancients’ interpretation of φρένες as ‘diaphragm’ is flawed. Φρονέω ‘to have (good) understanding or intelligence’ is a back-formation coined after ἀφρονέω ‘to act senselessly, to be foolish’. From zero-graded ἀφραίνω (via a synchronic reanalysis of -αίνω as a deverbative suffix of the type °φαίνω), an adverb *ἀφρα-δόν ‘senselessly, foolishly’ was eventually coined, which was the starting point of a whole new group. From this group was reanalyzed a “new” synchronic root √φραδ- ‘to heed, to consider’, reflected by Hom. φράζω. The lack of comparative evidence for this sprawling word family leads the author to assume that Hom. ἄφρων [adj.] ‘senseless, fool, heedless’ is in fact the reflex of a PIE etymon *ń̥ -gʷʱr(h1)-on- ‘without sense of smell, not able of scenting’, from PIE *gʷʱreh 1- ‘to smell’ (cf. Ved. jí-ghr-a- < *gʷʱí-gʷʱr(h 1)-V-). This verbal compound of the type νήφων [*-on-adj.] ‘sober’ (< PIE *ń̥-h 1gʷʱ-on- ‘not having drunk’) would have been eventually reanalyzed as a privative bahuvrīhi (viz. ‘lacking φρένες’).

In the article, the structure and key content aspects of the new textbook Economy of Benelux Countries by E. A. Sergeev, PhD in Economics, Associate Professor of the Departments of World Economy and History and Politics of European and American Countries at MGIMO-University, Senior Researcher at the Institute of International Studies (MGIMO), and Zh. N. Komissarova, PhD in Economics, Associate Professor of the Department of World Economy at MGIMO-University. There still exist gaps in Russian research of small European countries and Belgium, the Netherlands, and Luxembourg in particular. The textbook is designed to fill one of these gaps and presents a comprehensive analysis of the three economies, covering topics from real, financial, and foreign economic sectors to social systems and enterprise size structure in the Benelux countries. The textbook is well-grounded with extensive illustrative material — numerous tables and graphs based on national and international statistics, including an original — first in Russian research — Dutch economic history periodization. Another significant advantage is the explanation of theoretical concepts (e. g., “small open economy”) using examples of Belgium, the Netherlands and Luxembourg, which not only familiarizes the reader with the (sub)region’s economy, but also increases their theoretical knowledge. The textbook also includes a thorough description of individual issues of particular relevance to Benelux — e. g., TNCs, demographic and migration is sues, labor market transformation and precarious employment, and regional economic imbalances. The textbook by E. A. Sergeev and Zh. N. Komissarova is thus of great importance for Benelux research and European studies, and is recommended for reading by university students, their teachers, and researchers

India has the world’s largest population employed in agriculture and related industries. According to the World Bank, about 43% of Indian population was employed in agriculture in 2019, and most of this population lives in rural areas. India has the world’s largest population living in the villages. According to the Indian census of 2011, 68% of its population, i. e., 833 million people, lived in rural areas. Although there has been a steady decline in the agricultural employment and rural population, India is still a country with the population closely linked to agriculture and rural areas

The paper presents a phenomenological generalized model of a first-order metamagnetic phase transition for the La(Fe, Si)13 compounds in the approximation of localized moments under the simultaneous action of temperature, field and pressure. To achieve the maximum cooling power of magnetic solid-state cooling devices, the Curie temperature of the working bodies should be fine-tuned by two external generalized forces: a magnetic field and pressure. The thermodynamic phenomenological models presented in the literature are mostly focused on the description of the behavior of magnetocaloric materials in the vicinity of phase transition in the absence of external pressure. In turn, the latter provide a significant reduction in the field hysteresis effect by shifting the Curie temperature and expand the working temperature range of the refrigerant. To estimate the required pressure value, a new generalized model was developed that excludes the linear dependence of the phase transition temperature on the volume change and modernizes the form of the magnetic and phonon entropy, taking into account anharmonism. In addition, the equations of state describing the behavior of working bodies underwent a multistimuli cooling cycle were obtained. The model allows estimating the upper limit of the temperature and field hysteresis and predicting the required external pressure to reduce the field hysteresis.