170 research outputs found
Thermal expansion and polarization of (1-x)PNNxPT solid solutions
The paper presents the results of detailed studies of the thermal
expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x¼0-
0.8. The anomalous and lattice contributions to deformation and the
thermal expansion coefficient are analyzed and the mean square
polarization Pd is determined. The results obtained are discussed
within the framework of the thermodynamic theory and the Landau
2-4-6 coefficients for solid solutions are estimate
The effect of the probe magnetic moment orientation of magnetic resonance force microscope on the spectra of spin wave resonances
This work was supported by the Russian Science Foundation (project 16-12-10254)
On the use of the continuous wiener filter to generalized fractional gaussian noise
The paper is devoted to the investigation of the continuous Kolmogorov–Wiener filter weight function for forecasting of the process described by the generalized fractional Gaussian noise model. Such a model may describe telecommunication traffic, see [1, 2]. Our recent papers were devoted to the corresponding weight function obtaining for the processes in the power-law structure function model [3–5], іn the “usual“ fractional Gaussian noise model [6–8] and in the Gaussian fractional sum-difference model [9]; see also a review in [10]. However, the corresponding investigation for the generalized fractional Gaussian noise model is not yet done. In [11] it is shown, in particular, that the continuous Kolmogorov–Wiener filter may be applied to prediction of smoothed heavy-tail processes. So, the problem under consideration is of interest
Investigation of the thermal expansion and heat capacity of the CaCu3Ti4O12 ceramics
The thermal expansion of the CaCu3Ti4O12 ceramics has been measured over a wide temperature
range 120–1200 K. The high quality of the samples under study has been confirmed by good agreement of
the results of measurements of the heat capacity in the range 2–300 K and in the vicinity of the phase transition of magnetic nature at 25 K with the data for the single crystal. No anomalies in the thermal expansion
that can be associated with the phase transition at 726–732 K assumed by other investigators have been found.
The influence exerted on the thermal expansion by the heat treatment of the sample in a helium atmosphere
and in air has been investigated
Spin state crossover in Co3BO5
We have investigated the spin and oxidation states of Co in Co3BO5 using x-ray magnetic circular dichroism (XMCD) and dc magnetic susceptibility measurements. At low temperatures, XMCD experiments have been performed at the Co K-edge in Co3BO5 and Co2FeBO5 single crystals in the fully ferrimagnetically ordered phase. The Co (K-edge) XMCD signal is found to be related to the Co2+ magnetic sublattices in both compounds, providing strong experimental support for the low-spin (LS) Co3+ scenario. The paramagnetic susceptibility is highly anisotropic. An estimation of the effective magnetic moment in the temperature range 100-250 K correlates well with two Co2+ ions in the high-spin (HS) state and some orbital contribution, while Co3+ remains in the LS state. The crystal structure of the Co3BO5 single crystal has been solved in detail at the T range 296-703 K. The unit cell parameters and volume show anomalies at 500 and 700 K. The octahedral environment of the Co4 site strongly changes with heating. The generalized gradient approximation with Hubbard U correction calculations have revealed that, at low-temperatures, the system is insulating with a band gap of 1.4 eV, and the Co2+ ions are in the HS state, while Co3+ are in the LS state. At high temperatures (T > 700 K), the charge ordering disappears, and the system becomes metallic with all Co ions in 3d7 electronic configuration and HS state. © 2021 American Physical Society.We acknowledge many inspirational discussions on the topic of this paper with the late Natalia Ivanova and Leonard Bezmaternykh. The authors acknowledge A. Ney for allowing us to use the XANES spectrum of film. We are grateful to the Russian Foundation for Basic Research (Project No. 20-02-00559) and President Council on Grants (Project No. МК-2339.2020.2) for supporting this paper. This paper was carried out within the state assignment of the Russian Ministry of Science and High Education via program “Quantum”' (No. AAAA-A18-118020190095-4). We also acknowledge support by Russian Ministry of Education and Science via Contract No. 02.A03.21.0006. We acknowledge financial support from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, Grant No. MAT2017-83468-R) and from the regional Government of Aragon (E12-20R RASMIA project)
Dielectric relaxation and phase transition behavior of (1–x)Pb(Zn1/3Nb2/3)O3-xBaTiO3 binary solid solutions
Dielectric relaxation and phase transition behaviors in (1–x)Pb(Zn1/3Nb2/3)O3-xBaTiO3 (PZN-BT) binary solid solutions have been systematically studied in this paper. All the compositions display a pure pseudo-cubic perovskite structure. As the BT contents increase from 10 mol% to 70 mol%, the phase transition peak becomes broader and broader, accompanying with decreases of ɛm (the maximum dielectric permittivity) and Tm (the temperature corresponds to the ɛm). Nevertheless, an abnormal increase of ɛm and Tm occurs when the BT contents exceeds 70 mol%, forming a “U” shaped curve of the compositional dependence of ɛm and Tm. Moreover, it is indicated from the new glass model fitting results that the characteristic parameter p, which represents the degree of relaxation, also shows a similar “U” shaped variation curve. Similarly, as shown in polarization-electric field loops, both remnant polarizations (Pr) and coercive fields (Ec) display the “U” shaped curve as the BT content changes from 10 mol% to 80 mol%. Finally, according to the similar variation of these key parameters mentioned above, a polarization mismatched model, which describes the destruction and reestablishment of the long range order arrangement in solid solutions composed of two kinds of ferroelectrics, is proposed to illustrate the underlying mechanism. In this PZN-BT system or other similar ABO3-type perovskite relaxors, the competition between the A-O and B-O coupling plays an important role to form the “U” shaped evolution of these key parameters. © 201
Первичная цилиарная дискинезия у ребенка с синдромом Симпсона-Голаби-Бемеля II типа вследствие мутации гена OFD1
Primary ciliary dyskinesia (PCD) is an orphan disease associated with mutations in several genes. It is a ciliopathy, an abnormality of the cilia and flagella. Ciliopathies include the extremely rare Simpson - Golabi - Bemel syndrome (SSGB) type II.The aim of this article is to familiarize the reader with the possibility of simultaneous presence of type II SSGB and PCD in a patient with bronchiectasis (BE).Results. The first clinical observation in the Russian literature is presented withhistory, physical examination, including clinical and morphologic examination, results of additional investigations and initiation of therapy. The case describes a 15-year-old patient with BE and other lesions typical of PCD confirmed on the basis of structural changes in the cilia of the respiratory epithelium of the trachea detected by transmission electron microscopy. The patient had a pathogenic mutation of the OFD1 gene responsible for the development of both type II SSGB and PCD.Conclusion. Several variants of ciliopathies may occur in one patient, and PCD may present as a syndrome.Первичная цилиарная дискинезия (ПЦД) является орфанным заболеванием, связанным с мутациями в различных генах, одной из разновидностей патологии ресничек и жгутиков — цилиопатий. К последним также относится крайне редко встречающийся синдром Симпсона—Голаби—Бемеля (ССГБ) II типа.Целью работы явилось ознакомление специалистов с возможностью одновременного присутствия у пациента с бронхоэктазами (БЭ) ССГБ II типа и ПЦД по данным клинического наблюдения.Результаты. Представлено первое в отечественной литературе клиническое наблюдение (данные анамнеза, объективного осмотра, включая клинико-морфологический осмотр, результаты дополнительных методов обследования и инициации терапии) 15-летнего пациента с БЭ и другими поражениями, типичными для ПЦД, подтвержденной на основании структурных изменений в ресничках респираторного эпителия трахеи, выявленных с помощью трансмиссионной электронной микроскопии, и патогенной мутации гена OFD1, ответственного за развитие как ССГБ II типа, так и ПЦД.Заключение. Установлено, что у одного пациента могут встречаться разные варианты цилиопатий, а ПЦД, таким образом, может иметь синдромальный характер
2020 Clinical guidelines for Atrial fibrillation and atrial flutter
Russian Society of Cardiology (RSC).With the participation of Russian Scientific Society of Clinical Electrophysiology, Arrhythmology and Cardiac Pacing, Russian Association of Cardiovascular Surgeons.Approved by the Scientific and Practical Council of the Russian Ministry of Health
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