Thermal stability of the cellular structure of an austenitic alloy after selective laser melting

Published ArticleThe thermal stability of the cellular structure of an austenitic Fe–17% Cr–12% Ni–2% Mo–1% Mn–0.7% Si–0.02% C alloy produced by selective laser melting in the temperature range 20–1200°C is investigated. Metallographic analysis, transmission electron microscopy, and scanning electron microscopy show that structural changes in the alloy begin at 600-700°C and are fully completed at ~1150°C. Differential scanning calorimetry of the alloy with a cellular structure reveals three exothermic processes occurring upon annealing within the temperature ranges 450–650, 800–1000, and 1050–1200°

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

QUALITY OF LIFE EVALUATION IN RECIPIENTS AFTER KIDNEY TRANSPLANTATION

Quality of life analysis of kidney graft recipients includes complex assessment of physical, psychological and social status and also certain laboratory and clinical studies. However we suppose that significance of the study might increase considerably if it would be multicenter. The objective of the present publication is to organize such a multicenter study. Obviously, quality of life of recipients with functioning transplanted kidney is undoubtedly of scientific interest and needs further extended studies that might contribute to better interpretation of long-term results after kidney transplantation

Nonlinear acousto-electric transport in a two-dimensional electron system

We study both theoretically and experimentally the nonlinear interaction between an intense surface acoustic wave and a two-dimensional electron plasma in semiconductor-piezocrystal hybrid structures. The experiments on hybrid systems exhibit strongly nonlinear acousto-electric effects. The plasma turns into moving electron stripes, the acousto-electric current reaches its maximum, and the sound absorption strongly decreases. To describe the nonlinear phenomena, we develop a coupled-amplitude method for a two-dimensional system in the strongly nonlinear regime of interaction. At low electron densities the absorption coefficient decreases with increasing sound intensity, whereas at high electron density the absorption coefficient is not a monotonous function of the sound intensity. High-harmonic generation coefficients as a function of the sound intensity have a nontrivial behavior. Theory and experiment are found to be in a good agreement.Comment: 27 pages, 6 figure

Study of growth temperature effect on wetting layer during In/GaAs droplet epitaxy

This work was supported by the Russian Science Foundation Grant No. 15-19-10006. The results were obtained using the equipment of the Research and Education Center and Center for Collective Use "Nanotechnologies" of Southern Federal University

High-temperature ferromagnetism of spsp electrons in narrow impurity bands: Application to CaB6_6

Ferromagnetism with high Curie temperature $T_c$, well above room temperature, and very small saturation moment has been reported in various carbon and boron systems. It is argued that the magnetization must be very inhomogeneous with only a small fraction of the sample ferromagnetically ordered. It is shown that a possible source of high $T_c$ within the ferromagnetic regions is itinerant electrons occupying a narrow impurity band. Correlation effects do not reduce the effective interaction which enters the Stoner criterion in the same way as in a bulk band. It is also shown how, in the impurity band case, spin wave excitations may not be effective in lowering $T_c$ below its value given by Stoner theory. These ideas are applied to CaB$_6$ and a thorough review of the experimental situation in this material is given. It is suggested that the intrinsic magnetism of the B$_2$ and O$_2$ dimers might be exploited in suitable structures containing these elements.Comment: 26 pages, 2 figure

Pseudogap behavior of nuclear spin relaxation in high Tc superconductors in terms of phase separation

We analyze anew experiments on the NMR in cuprates and find an important information on their phase separation and its stripe character hidden in the dependence of $1/^{63}T_{1}$ on degree of doping. In a broad class of materials $1/^{63}T_{1}$ is the sum of two terms: the temperature independent one attributed to ``incommensurate'' stripes that occur at external doping, and an ``universal'' temperature dependent term ascribed to moving metallic and AF sub-phases. We argue that the frustrated first order phase transition in a broad temperature interval bears a dynamical character.Comment: 5 pages, 3 figures; some comments and references added; accepted for publication in JETP Letter

ОСОБЕННОСТИ СОСТОЯНИЯ ОРГАНА ЗРЕНИЯ У ПАЦИЕНТОВ ПОСЛЕ ТРАНСПЛАНТАЦИИ ПОЧКИ

Structural changes in eyes are present in all patients with chronic kidney disease. A study to detect ocular patho- logy in patients with end-stage chronic renal failure after kidney transplantation in the early and late postopera- tive period compared with patients receiving replacement therapy with hemodialysis. Revealed that in the early post-transplant period in recipients of kidneyas in patients on hemodialysis, continued angioretinopatiya, 40% of patients had «dry eye syndrome». In the delayed post-transplant period, patients showed significant impro- vement in the retina and retinal vessels, the improvement of spatial-temporal parameters of visual perception. However, a decrease of visual acuity on the background of the development of posterior subcapsular cataract caused by prolonged corticosteroid, and an increased incidence of viral and bacterial conjunctivitis. Структурные изменения органа зрения имеются у всех больных с хронической болезнью почек. Проведе- но исследование для выявления глазной патологии у больных с терминальной стадией ХПН после транс- плантации почки в раннем и отдаленном периоде в сравнении с пациентами, получающими заместитель- ную терапию гемодиализом. Выявлено, что в раннем посттрансплантационном периоде у реципиентов ПАТ, как и у пациентов на гемодиализе, сохранялась ангиоретинопатия, у 40% пациентов отмечался син- дром «сухого глаза». В отсроченном посттрансплантационном периоде у пациентов выявлено значимое улучшение состояния сетчатки и ретинальных сосудов, улучшение пространственно-временных показа- телей зрительного восприятия. Однако отмечалось снижение остроты зрения на фоне развития задней субкапсулярной катаракты, обусловленной длительным приемом кортикостероидов, и увеличение часто- ты вирусных и бактериальных конъюнктивитов.

Orbital Magnetoresistance in the LaSrCuO System

Measurements of resistivity, Hall effect, and magnetoresistance have been made on seven c-axis oriented thin-film specimens of La(2-x)Sr(x)CuO(4) with values of x from 0.048 to 0.275, and one specimen that also contains Nd. The orbital magnetoresistance is found not to be proportional to the square of the tangent of the Hall angle except for values of x near 0.15 above about 80K. For smaller values of x the temperature dependence of the magnetoresistance is different, but quite similar in the various specimens, in spite of large differences in resistivity, Hall coefficient, and Hall angle.Comment: LaTeX, 14 pages, 4 embedded color eps figure