Conditions for the formation of a non-autonomous phase at the structural deformation of complex vanadium oxides

Received: 02.03.2018. Accepted: 10.04.2018. Published: 10.05.2018.A new previously unknown effect of a reversible transition from a singlephase system to a heterophase system containing a non-autonomous phase was observed during thermal and chemical deformations of the Zn2–2xCd2xV2O7 structure.The role of local symmetry in the formation of the non-autonomous phase is shown on the basis of X-ray diffraction studies in situ and a comparative crystal-chemical analysis of the structural deformations of isoform monoclinic solid solutions of zinc and copper pyrovanadates with zero volumetric thermal expansion.The work was supported by UB RAS (project 18-10-3-32)

Structure and properties of the intercalation compound FexTiTe2

The FexTiTe2 system, which belongs to the class of materials with the electronic spectrum containing below the Fermi level the band of localized states with a strong temperature dependence of the band width, has been investigated experimentally. Heating of the material leads to a broadening of the band of localized states. When the top of this band crosses with the Fermi level, the effect of retrograde solubility is observed in the system; i. e., the metal precipitates to the composition ensuring the absence of increase in the Fermi energy during heating. The influence of the band of localized states on the structure of the material and its magnetic and electrical properties has been analyzed. © 2013 Pleiades Publishing, Ltd

Problems and prospects of human capital development in modern Russia

Purpose: In the context of dynamically changing modern labor market there is a need to develop a model of congruence and correlation of the process of building professional competencies provided by educational standards. Design/Methodology/Approach: The study was performed using monographic, abstract logical, sociological and statistical methods. However, this approach does not imply the formation of supra-professional competencies, which generally predetermine the success of professional tasks performed by a specialist. Findings: The article discusses the role of human capital as a fundamental factor affecting the increase in the competitiveness of production. Practical implications: The study focusses on the most demanded competencies for the development of digital society. The authors have grouped countries by level of human capital use. Originality/Value: At present, the appropriate parameters for measuring professional and general cultural competencies have been adopted as a system for assessing the quality of education in general and the quality of specialist training.peer-reviewe

In situ synthesis, structural chemistry and vibrational spectroscopy of Zn-doped Ca5Mg4(VO4)6

The phase formation of the solid solution Ca5Mg4–xZnx(VO4)6 (0≤x≤4) was studied in situ using differential scanning calorimetry and high-temperature X-Ray powder diffraction (XRPD). XRPD analysis shows the appearance of unavoidable secondary pyrovanadate phases using conventional synthesis methods. The local structure of the solid solution was verified by vibrational spectroscopy. The analysis of the infrared and Raman spectroscopy data allows establishing the main features between vanadate garnets and their isostructural analogs among natural silicates

Native and Activated Hepatic Stellate Cells Stimulate Liver Regeneration in Rats After Partial Hepatectomy and 2-Acetylaminofluorene Injection

© 2016, Springer Science+Business Media New York.One the current challenges of modern hepatology is to find new approaches to stimulate liver regeneration and to find new methods for liver disease treatment. Cell therapies, which are based on using regional stem cells for disease treatment, are under active development. However, studies, devoted to their transplantation, are currently scarce. In recent years, hepatic stellate cells are considered to be hepatic stem cells. It is known that activated hepatic stellate cells can transdifferentiate into myofibroblasts and lead to liver fibrosis. The aim of our work was to study the influence of native and activated hepatic stellate cells in vivo by lead nitrate injection after transplantation into partial hepatectomized rats, which is considered to be a classical model to study liver regeneration. Injection of 2-acetylaminofluorene (AAF), which selectively eliminates hepatocyte proliferation, was used to understand the hepatic stellate cells role in liver regeneration process better. Our results suggest that transplanted native and activated hepatic stellate cells can differentiate into hepatocyte-like cells and positively influence liver regeneration without inducing liver fibrosis

Heat-mode excitation in a proximity superconductor

Mesoscopic superconductivity deals with various quasiparticle excitation modes, only one of them -- the charge-mode -- being directly accessible for conductance measurements due to the imbalance in populations of quasi-electron and quasi-hole excitation branches. Other modes carrying heat or even spin, valley etc. currents populate the branches equally and are charge-neutral that makes them much harder to control. This noticeable gap in the experimental studies of mesoscopic non-equilibrium superconductivity can be filled by going beyond the conventional DC transport measurements and exploiting spontaneous current fluctuations. Here, we perform the first experiment of this kind and investigate the transport of heat in an open hybrid device based on a superconductor proximitized InAs nanowire. Using shot noise measurements we observe a novel effect of sub-gap Andreev heat guiding along the superconducting interface and fully characterize it in terms of the thermal conductance on the order of $G_\mathrm{th}\sim e^2/h$, tunable by a back gate voltage. Understanding of the heat-mode also uncovers its implicit signatures in the non-local charge transport. Our experiments open a direct pathway to probe generic neutral excitations in superconducting hybrids.Comment: revised, 20 pages with supplementa

Intrinsic mechanisms of the superconducting transition broadening in epitaxial TiN films

We investigate the impact of various fluctuation mechanisms on the dc resistance at the superconducting resistive transition (RT) in epitaxial titanium nitride (TiN) films. The studied samples demonstrate a relatively steep RT with $\delta T/T_\mathrm{c}$ $\sim 0.002 - 0.025$ depending on the film thickness (20, 9, and 5\, nm) and device dimensions. The transition is significantly broader than predicted by a conventional theory of superconducting fluctuations ($\delta T/T_\mathrm{c} \ll 10^{-3}$), which can be can be tackled by the effective medium theory of RT in an inhomogeneous superconductor. We propose that the underlying inhomogeneity has intrinsic origin and manifests via two microscopic mechanisms - static and dynamic. The dynamic inhomogeneity is associated with spontaneous fluctuations of the electronic temperature ($T$-fluctuations), whereas the static one is related to random spatial distribution of surface magnetic disorder (MD) present in TiN films. Our analysis reveals distinct dependencies of the RT width on the material parameters and device dimensions for the two mechanisms, which allows to disentangle their contributions in experiment. We find that while the $T$-fluctuations may contribute a sizeable part of the measured RT width, the main effect is related to the MD mechanism, which is quantitatively consistent with the data in a wide range of sample dimensions. Given the fact that both microscopic mechanisms are almost inevitably present in real devices, our results provide a novel perspective of microscopic origin of the RT broadening and inhomogeneity in thin superconducting films.Comment: prepared for resubmission. see also related arXiv:2202.0630

Frequencies of wave packets of whistler-mode chorus inside its source region: a case study

Whistler-mode chorus is a structured wave emission observed in the Earth's magnetosphere in a frequency range from a few hundreds of Hz to several kHz. We investigate wave packets of chorus using high-resolution measurements recorded by the WBD instrument on board the four Cluster spacecraft. A night-side chorus event observed during geomagnetically disturbed conditions is analyzed. We identify lower and upper frequencies for a large number of individual chorus wave packets inside the chorus source region. We investigate how these observations are related to the central position of the chorus source which has been previously estimated from the Poynting flux measurements. We observe typical frequency bandwidths of chorus of approximately 10% of the local electron cyclotron frequency. Observed time scales are around 0.1 s for the individual wave packets. Our results indicate a lower occurrence probability for lower frequencies in the vicinity of the central position of the source compared to measurements recorded closer to the outer boundaries of the source. This is in agreement with recent research based on the backward wave oscillator theory