Influence of intermartensitic transitions on transport properties of Ni2.16Mn0.84Ga alloy

Magnetic, transport, and x-ray diffraction measurements of ferromagnetic shape memory alloy Ni$_{2.16}$Mn$_{0.84}$Ga revealed that this alloy undergoes an intermartensitic transition upon cooling, whereas no such a transition is observed upon subsequent heating. The difference in the modulation of the martensite forming upon cooling from the high-temperature austenitic state [5-layered (5M) martensite], and the martensite forming upon the intermartensitic transition [7-layered (7M) martensite] strongly affects the magnetic and transport properties of the alloy and results in a large thermal hysteresis of the resistivity $\rho$ and magnetization $M$. The intermartensitic transition has an especially marked influence on the transport properties, as is evident from a large difference in the resistivity of the 5M and 7M martensite, $(\rho_{\mathrm{5M}} - \rho_{\mathrm{7M}})/\rho _{\mathrm{5M}} \approx 15$, which is larger than the jump of resistivity at the martensitic transition from the cubic austenitic phase to the monoclinic 5M martensitic phase. We assume that this significant difference in $\rho$ between the martensitic phases is accounted for by nesting features of the Fermi surface. It is also suggested that the nesting hypothesis can explain the uncommon behavior of the resistivity at the martensitic transition, observed in stoichiometric and near-stoichiometric Ni-Mn-Ga alloys.Comment: 7 pages, 6 figures, REVTEX

Premartensitic transition driven by magnetoelastic interaction in bcc ferromagnetic Ni2MnGaNi_{2}MnGa

We show that the magnetoelastic coupling between the magnetization and the amplitude of a short wavelength phonon enables the existence of a first order premartensitic transition from a bcc to a micromodulated phase in $Ni_{2}MnGa$. Such a magnetoelastic coupling has been experimentally evidenced by AC susceptibility and ultrasonic measurements under applied magnetic field. A latent heat around 9 J/mol has been measured using a highly sensitive calorimeter. This value is in very good agreement with the value predicted by a proposed model.Comment: 4 pages RevTex, 3 Postscript figures, to be published in Physical Review Letter

Comparison of Mathematical Methods for Compensating a Current Signal Under Current Transformers Saturation Conditions

Current measurements from electromagnetic current transformers are essential for the construction of secondary circuit systems, including for protection systems. Magnetic core of these transformers are at risk of saturation, as a result of which maloperation of protection algorithms can possibly occur. The paper considers methods for recovering a current signal in the saturation mode of current transformers. The advantages and disadvantages of methods for detecting the occurrence of current transformers core saturation are described. A comparative analysis of mathematical methods for recovering a current signal is given, their approbation was carried out, and the most promising of them was revealed. The stability and sensitivity of recovery methods were tested by adding white noise to the measured signal and taking into account the initial flux density (remanent magnetization) in the current transformers core. Their comparison is given on the basis of angular, magnitude, and total errors at a given simulation interval. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was supported in part by the International Cooperation Project of National Natural Science Foundation of China under Grant 41761144079, in part by the Strategic Priority Research Program of the Chinese Academy of Sciences, in part by the Pan-Third Pole Environment Study for a Green Silk Road under Grant XDA20060303, in part by the K. C.Wong Education Foundation under Grant GJTD-2020-14, in part by the CAS PIFI Fellowship under Grant 2021PC0002, in part by the Xinjiang Tianchi Hundred Talents Program under Grant Y848041, in part by the CAS Interdisciplinary Innovation Team under Grant JCTD-2019-20, in part by the project of the Research Center of Ecology and Environment in Central Asia under Grant Y934031, and in part by the Regional Collaborative Innovation Project of Xinjiang Uygur Autonomous Regions under Grant 2020E01010

METEORITE TSAREV L5 FUSION CRUST: EXPERIMENTAL RESULT AFTER THE THERMAL IMPACT

We studied the structure of the Tsarev L5 meteorite sample fusion crust using optical and electron microscopy.Работа выполнена при финансовой поддержке Министерства образования и науки Российской Федерации (базовое финансирование по проекту № 3451) и Правительства Российской Федерации, Акт 211, Соглашение № 02.A03.21.0006

ПРИМЕНЕНИЕ БИОПРОТЕЗОВ В ХИРУРГИИ МИТРАЛЬНЫХ ПОРОКОВ: ВОЗМОЖНОСТИ ОТКАЗА ОТ АНТИКОАГУЛЯНТНОЙ ТЕРАПИИ

Aim. To evaluate the clinical efficacy of gradual sinus rhythm restoration, including the bioprosthetic mitral valve replacement combined with maze radiofrequency ablation, external cardioversion and catheter ablation.Methods.102 medical records of patients with mitral valve disease and long-standing atrial fibrillation (4,7±2,7 years) were restrospectively reviewed. Maze procedure was performed under extracorporeal circulation before the mitral valve replacement. The endpoints were monitored at the day of surgery, at discharge, and 3, 6 and 12 months after surgery.Results.Sinus rhythm was recorded in 65.7% of patients at discharge from the hospital. The completeness of the follow-up was 80.4%. Steady regular rhythm was maintained in 64.6 % of patients in the study group. Other patients (35.4%) underwent cardioversion with the efficacy rate of 41.4%. Anticoagulation therapy was withdrawn in 65.9% of patients three months after surgery. 18.3% of patients with symptomatic arrhythmia underwent catheter ablation, which allowed to restore sinus rhythm in 73.3% of cases. Sinus rhythm was recorded in 92.7% of cases within the 1-year follow-up. Importantly, 79.3% of patients were discontinued of indirect anticoagulants. Conclusion. Discontinuation of indirect anticoagulants proved its beneficial effects and safety on the restoration of sinus rhythm in patients after bioprosthetic mitral valve replacement.Цель. Оценка клинической эффективности последовательной стратегии восстановления синусового ритма (СР), включающей протезирование митрального клапана биопротезом с одномоментной радиочастотной аблацией по методике «лабиринт», наружную электроимпульсную терапию и катетерную аблацию.Материалы и методы. Проанализированы результаты хирургического лечения 102 пациентов с митральными пороками сердца и продолжительным анамнезом фибрилляции предсердий (4,7±2,7лет). Радиочастотную аблацию «лабиринт» выполняли в условиях искусственного кровообращения до этапа биопротезирования митрального клапана. Контрольные точки исследования – день операции, день выписки из стационара, три, шесть и 12 месяцев после вмешательства.Результаты. При выписке из клиники СР регистрировали у 65,7% пациентов. Полнота наблюдения на амбулаторном этапе составила 83,7%. Устойчивый правильный ритм в наблюдаемой группе сохранялся в 64,6% случаев. Остальным пациентам (35,4%) проведена электроимпульсная терапия, эффективность которой составила 41,4%. Спустя три месяца после оперативного вмешательства антикоагулянтная терапия отменена 65,9% пациентов. 18,3% пациентов с симптомной аритмией выполнена повторная катерная аблация, в результате которой в 73,3% случаев восстановлен СР. К концу годового этапа СР регистрировали в 92,7% случаев, при этом у 79,3% пациентов были отменены непрямые антикоагулянты.Заключение.Продемонстрирована высокая эффективность и безопасность предложенной стратегии восстановления СР при использовании биопротезов в хирургии митральных пороков с позиции возможности отказа от непрямых антикоагулянтов

INVESTIGATION OF THE SPECTRAL CHARACTERISTICS OF POLYVINYLPYRROLIDONE-IODINE IN THE FIELD OF LOW-FREQUENCY VIBROACOUSTIC OSCILLATIONS

The change in the optical density spectrum of povidone-iodine in the field of low-frequency oscillations was studied. A conclusion about the dissociation of the complex under the action of infrasound is made. Partially confirmed data on the structure of the complex

Отзывчивость сои на внесение органических удобрений на основе птичьего помета

Organic fertilizers based on chicken manure have a diverse composition of basic nutrients and microelements, which is their advantage over mineral fertilizers. The introduction of organic fertilizers obtained based on chicken manure improves the biological activity of the soil. The study aims to determine the effectiveness of using bird droppings as an organic fertilizer to conserve soil bioresources and increase soybean productivity. In the course of the work, the authors tested new organic fertilizers based on chicken manure obtained using a cavitationvortex heat generator by processing semi-dry manure. Their influence on soil microbiological indicators, growth, development, and biometric characteristics of soybean plants, phytosanitary condition of crops, productivity, and product quality was revealed. The authors also found that fertilizers based on chicken manure help to improve the microbiological characteristics of the soil, which increases the availability of nutrients for plants. The authors note a change in the number of mycomycetes at the beginning of the growing season: a decrease of 68% with the use of Preparation 1 and an increase of 35.6% with the use of nitrogen fertilizers. Pre-sowing introduction of preparations into the soil and processing during the growing season activate the vegetative development of plants and contribute to an increase in the yield of green mass and grain. The greatest effect was obtained when preparation 2 was applied under soybean. The increase in soybean grain yield was 0.2–0.3 t/ha or 8–14% of the control. The authors also found that treatment with drugs improves the structural parameters of soybean plants: the number of beans per plant increases by 6–8%; by 18–23% - the mass of grains from one plant; the safety of plants for harvesting increases by 2–4%.Органические удобрения на основе куриного помета имеют разнообразный состав основных элементов питания и микроэлементов, в этом их преимущество над минеральными удобрениями. Внесение органических удобрений, полученных на основе куриного помета, улучшает биологическую активность почвы. Цель исследований – определить эффективность использования птичьего помета в качестве органического удобрения для сохранения биоресурсов почвы и повышения продуктивности сои. В процессе выполнения работы были испытаны новые органические удобрения на основе куриного помета, полученные при использовании кавитационно-вихревого теплогенератора методом переработки полусухого помета. Выявлено их влияние на микробиологические показатели почвы, рост, развитие и биометрические характеристики растений сои, фитосанитарное состояние посевов, урожайность и качество продукции. Установлено, что удобрения, полученные на основе куриного помета, способствуют улучшению микробиологических характеристик почвы, что повышает доступность элементов питания для растений. Отмечено изменение численности микомицетов в начале вегетации: снижение на 68 % при использовании Препарата 1 и увеличение на 35,6 % при применении азотных удобрений. Предпосевное внесение препаратов в почву и обработка по вегетации активизируют вегетативное развитие растений и способствуют повышению урожайности зеленой массы и зерна. Наибольший эффект получен при внесении под сою Препарата 2. Прибавка урожайности зерна сои составила 0,2–0,3 т/га, или 8–14 % к контролю. Установлено, что обработка препаратами улучшает структурные показатели растений сои: на 6–8 % увеличивается количество бобов на растении и на 18–23 % – масса зерен с одного растения. На 2–4 % возрастает сохранность растений к уборке