The National Research University "Belgorod State University" (BelSU) (Russian: Белгородский государственный национальный исследовательский университет (НИУ БелГУ)) is a university in Belgorod, Russia. Belgorod State University is one of the oldest universities in Belgorod and the largest university in the Belgorod region. The university has 25,000 students from 85 regions of Russia, 1800 foreign students from 76 countries, 72 institutions and faculty, 2 branches, 98 departments and 74 research centers and laboratories..
The paper presents a study of various structural-phase states of the Fe-Mn-5Si alloy after severe plastic deformation by equal channel angular pressing and high-pressure torsion. Various physical and mechanical characteristics of the alloy were experimentally measured and analyzed in the austenitic coarse-grained, nanostructured grain-subgrain and twinned states, as well as in the predominantly martensitic and two-phase ultrafine-grained states. Indentation methods were used to find that severe plastic deformation increases the modulus of elasticity, the work of elastic deformation, and its elastic component, reducing the contact rigidity of the indenter with the deformed material and the work of plastic deformation. In this case, the alloy in the two-phase state after deformation has the lowest modulus of elasticity and work of plastic deformation at the highest work of elastic deformation.
Herein, a new high Co-Ni secondary hardening steel strengthened by co-precipitation of NiAl, Cu-rich precipitates (CRPs), and carbides was developed by optimizing the precipitation strategy. The evolution behavior of multiple precipitates and their effect on strength and ductility of new steel during aging at 460 degrees C were systematically investigated. The results reveal that the experimental steel exhibited unique mechanical properties at different aging stages, specifically, low stress brittle fracture at the initial stage of aging, superior combination of strength (2.5 GPa) and ductility (similar to 8.5 %) at the peak stage of aging, and high strength and low ductility at the over-aging stage. Three-dimensional atom probe results showed that the precipitation sequence of NiAl and CRPs in steel was as follows: supersaturated solid solution -> isolated NiAl precepitates -> NiAl/Cu co-precepitates, and the mechanism of NiAl on M2C was to induce nucleation and inhibit growth. Furthermore, the contribution of each strengthening factor was quantitatively assessed, and the high yield strength of peak-aging samples was attributed to precipitation strengthening (similar to 1121 MPa) and dislocation strengthening (similar to 995 MPa). Exceeding the peak aging, precipitation strengthening mechanism changes from the mixed mechanism of shearing and Orowan looping to one dominated by Orowan looping. This work constructs the correlation of "aging time-precipitate characteristics-fracture stress" based on the transition of yield strength and cleavage fracture stress, which provides a new insight for revealing the failure law of materials.
Transition metal ditellurides (CrTe2, MoTe2, WTe2) are promising materials for spintronics and phase-change electronics. However, their synthesis by conventional methods is challenging. The process is time-consuming and often yields non-stoichiometric products due to the high volatility of tellurium. Herein, we report a single-stage, ultrafast synthesis of these compounds via a novel Pressureless Reactive Spark Plasma Sintering (PRSPS) method. We first demonstrate that the standard reactive SPS approach, even under minimal pressure (5 MPa), is unsuitable for systems with low-melting-point components, as it causes the extrusion of molten tellurium from the reaction zone. To overcome this, a bespoke, quasi-sealed die assembly was engineered and successfully implemented, isolating the reactants from external pressure and preventing material loss. Using this pressureless method, phase-pure and highly crystalline powders of CrTe2, MoTe2, and WTe2 were successfully synthesized in a record time of just 15 min. Comprehensive characterization by XRD, SEM, and EDS confirmed their phase purity, stoichiometric composition (M:Te approximate to 1:2), and microcrystalline plate-like morphology. This method represents a paradigm shift in chalcogenide synthesis, reducing process times from days to minutes and providing a scalable route to high-quality powders.
Пандемия COVID-19 и введённые в этот период ограничительные меры оказали существенное влияние на состояние здоровья лиц пожилого возраста. В этой связи особый интерес представляет оценка изменений гериатрического статуса, в частности перехода от состояния преастении к сформированному синдрому старческой астении, в условиях длительного ограничения двигательной активности и социальной изоляции. Цель исследования — анализ динамики гериатрического статуса пациентов пожилого возраста при продолжительном пребывании в условиях сниженной мобильности в период локдауна. В исследование были включены 525 пациентов 65–74 лет, проживавших в стационарных учреждениях социального обслуживания. Всем участникам выполняли комплексную гериатрическую оценку, предусматривавшую контроль соматических показателей (АД, ЧСС, ИМТ), проведение кистевой динамометрии и теста шестиминутной ходьбы. Обследование проводили исходно, а также через 1 и 6 мес наблюдения. В течение 6 мес были отмечены выраженные неблагоприятные изменения структуры гериатрического статуса. Частота преастении уменьшилась с 35,8 до 14,1 %, что было связано с переходом значительной части пациентов в категорию старческой астении. Одновременно распространённость синдрома старческой астении увеличилась с 49,5 до 72 %. Кроме того, зарегистрировано увеличение числа пациентов с лёгкой, умеренной и выраженной степенью астении на 11,6; 6,1 и 4,4 % соответственно. Полученные результаты свидетельствуют о том, что длительное ограничение подвижности и социальная изоляция являются значимыми факторами ухудшения гериатрического статуса и ускоряют прогрессирование астенических изменений. Это подтверждает необходимость раннего выявления преастении и своевременного проведения профилактических и коррекционных мер, направленных на сохранение функциональной независимости пациентов пожилого возраста. The COVID-19 pandemic and the restrictive measures introduced during this period had a significant impact on the health status of older adults. In this regard, particular interest is focused on assessing changes in geriatric status, especially the transition from prefrailty to established frailty syndrome under conditions of prolonged physical inactivity and social isolation. The aim of the study was to analyze the dynamics of geriatric status in older patients during prolonged exposure to reduced mobility conditions during lockdown. The study included 525 patients aged 65–74 years residing in residential social care institutions. All participants underwent comprehensive geriatric assessment, including monitoring of somatic parameters (blood pressure, heart rate, and body mass index), handgrip dynamometry, and the six-minute walk test. Examinations were performed at baseline and repeated after 1 and 6 months of follow-up. It was established that marked unfavorable changes in the structure of geriatric status occurred over the six-month observation period. The prevalence of prefrailty decreased from 35.8 to 14.1%, which was associated with the transition of a substantial proportion of patients to the frailty category. At the same time, the prevalence of frailty syndrome increased from 49.5 to 72%. In addition, the number of patients with mild, moderate, and severe frailty increased by 11.6, 6.1 and 4.4%, respectively. The obtained results indicate that prolonged mobility restriction and social isolation are significant factors contributing to deterioration of geriatric status and acceleration of frailty progression. These findings confirm the importance of early identification of prefrailty and timely implementation of preventive and corrective interventions aimed at preserving functional independence in older patients.
В контексте интернационализации высшего образования и интенсификации академической мобильности особую значимость приобретает формирование навыков аудирования у иностранных студентов, изучающих русский язык как иностранный на довузовском этапе. Аудирование рассматривается как один из наиболее сложных видов речевой деятельности, особенно для китайских учащихся, что обусловлено существенными различиями между русским и китайским языками в фонетической системе, интонационном оформлении и механизмах речевого восприятия. Целью данного исследования является анализ эффективности применения цифровых образовательных инструментов для развития навыков аудирования у китайских студентов и определение их педагогического потенциала. Научная новизна и практическая значимость работы заключаются в рассмотрении цифровых средств как способа частичной компенсации отсутствия естественной языковой среды, а также в учёте лингводидактических особенностей китайской аудитории. В исследовании использованы данные анкетирования 15 китайских студентов довузовского этапа обучения. Опрос проводился с применением шкалы Лайкерта, а полученные данные подверглись анализу методами описательной статистики. Результаты исследования продемонстрировали, что цифровые инструменты наиболее эффективно способствуют расширению лексического запаса, повышению учебной мотивации, более глубокому пониманию структуры диалога и работе с аутентичными речевыми образцами. В то же время развитие навыков граматического и фонетического восприятия требует дополнительной методической поддержки со стороны преподавателя. В заключении подчёркивается важность методически обоснованного, избирательного и дифференцированного использования цифровых образовательных ресурсов в процессе обучения аудированию китайских студентов. In the context of the internationalization of higher education and the intensification of academic mobility, the development of listening skills among international students studying Russian as a foreign language at the pre-university stage is becoming particularly important. Listening is considered one of the most challenging types of speech activity, especially for Chinese learners, which is due to significant differences between the Russian and Chinese languages in their phonetic systems, intonation patterns, and mechanisms of speech perception. The aim of this study is to analyze the effectiveness of using digital educational tools for developing listening skills among Chinese students and to determine their pedagogical potential. The scholarly novelty and practical significance of the work lie in viewing digital tools as a means of partially compensating for the lack of a natural language environment, as well as in accounting for the linguodidactic specifics of the Chinese audience. The study utilizes data from a questionnaire survey of 15 Chinese students at the pre-university stage of education. The survey was conducted using a Likert scale, and the obtained data were analyzed using descriptive statistics methods. The results of the study demonstrated that digital tools most effectively contribute to expanding vocabulary, increasing learning motivation, deepening the understanding of dialogue structure, and working with authentic speech samples. At the same time, the development of grammatical and phonetic listening skills requires additional methodological support from the instructor. In conclusion, the importance of a methodologically sound, selective, and differentiated use of digital educational resources in teaching listening to Chinese students is emphasized.
