The article represents a translation of Section 6.2 of the monograph authored by A.S. Burlov, V.G. Vlasenko, D.A. Garnovskiy, A.I. Uraev, E.I. Maltsev, D.A. Lypenko, and A.V. Vannikov,
...Electroluminescent Organic Light-Emitting Diodes Based on Metal Coordination Compounds
, Rostov-on-Don: Yuzhn. Fed. Univ., 2015; ISBN 978-5-9275-1469-4 (see Additional Information), dedicated to reviewing the photoluminescence and electroluminescence properties of metal complexes based on (Zn, Cd, Al, Sc, Be, B) with azoles (2-(2-hydroxyphenyl)benzothiazoles, 2-(2-hydroxyphenyl)benzoxazoles, 2-(2-hydroxyphenyl)benzimidazoles, azaindoles, oxadiazoles, and their derivatives) as ligands. Modifying such ligands by introducing electron-donating substituents into various positions of the phenyl fragments leads to significant changes in their electroluminescence characteristics. Metal complex compounds with ligands of this type are widely used for creating OLED devices emitting white light.
The upper critical field of an iron-based SrFe
2 −
x
Ni
x
As
2
superconductor single crystal is measured for the first time in longitudinal and transverse magnetic fields up to 16 T in the basal
ab
...plane and to it along the
c
axis. The
H
c2
(0) values are 18 and 25 T for
H
∥
c
and
H
∥
ab
, respectively. The anisotropy of the upper critical field γ(
T
) =
H
c2
ab
/
H
c2
c
decreases monotonically to 1.4 with decreasing temperature. The temperature dependence of
H
c2
is not described fully by the Werthamer–Helfand–Hohenberg model taking into account the influence of orbital and spin paramagnetic effects. However, an effective two-band model reproduces well the measured temperature dependence. This indicates the two-band nature of this superconductor, where one of the bands is almost isotropic. According to the two-band model approximation, the contribution from the anisotropic band dominates near
T
c
, whereas the main contribution at low temperatures comes from the isotropic band with a lower diffusion coefficient.
This article presents the results of experimental studies and economic analysis in the field of atmospheric freeze drying (AFD), analyzes the features of the processes of sublimation of polydisperse ...materials of animal and vegetable origin. Using the results of this work will reduce energy intensity and increase the efficiency of sublimation technologies in industrial production. An economic analysis of the feasibility of atmospheric freeze-drying technology is carried out according to discounted indicators. The values of the terms of the project implementation are obtained and practical recommendations on the modes and parameters of drying are given.
Until now, there is no radical method of treating children with cerebral palsy, which allows us to consider scientific research in this direction reasonable and promising.
The aim of the research:
to ...study the effect of exercises on the mini-simulator “Kinesioplatform-swing” with biofeedback on the indicators of motor skills in children with spastic cerebral palsy.
Materials and methods.
We conducted an open, non-randomized, prospective, comparative, controlled study in pairs (each participant in the main group corresponds to a participant in the control group). The study involved 53 patients aged 4–12 years with cerebral palsy: the intervention group (group 1: n = 27 (13 boys, 14 girls)) and the control group (group 2: n = 26 (11 boys, 15 girls)), comparable in terms of gender, age and severity of movement disorders. Characteristics of the medical intervention: group 1 – botulinum toxin type A (BTA, for exercising against the background of relative muscular normotonus) + exercise therapy + exercises on the mini-simulator “Kinesioplatform-swing” with biofeedback (BFB); group 2 – BTA + exercise therapy. Duration of the study: 2019–2020. The difference between groups in terms of motor skills on the day of hospitalization and after completion of the training program (10 sessions each) was determined. Motor skills were assessed according to the GMFM-66/88 (Gross Motor Function Measure) table using the “Scales for measuring global motor functions”.
Results.
The inclusion of additional exercises on the mini-simulator “Kinesioplatformswing” with biofeedback in the rehabilitation of patients with movement disorders with spastic cerebral palsy (BTA + exercise therapy) in comparison with the control group. However, the question of the long-term effects of such training remains open and requires further study.
It is known that, during the synthesis of superconducting EuRbFe
4
As
4
single crystals, inclusions of its parent phase EuFe
2
As
2
are encountered. The kinetics of the formation of the orthorhombic ...phase in EuRbFe
4
As
4
crystals containing a large fraction of the EuFe
2
As
2
phase is studied using polarization optical microscopy. It is shown that the orthorhombic phase grows into the tetragonal one in the form of stripes that form macrodomains with one of the possible crystallographic orientations. Then these domains are abruptly penetrated by parallel stripes of the orthorhombic phase having the second orientation, as a result of which a twin system of orthorhombic domains is formed. The process is accompanied by the appearance of macrostresses: stretching and compression waves with a characteristic period of 100–300 μm along and across the twin system, which lead to spatial modulation of the magnetic permeability. It is found that even weak magnetic fields (up to 100 Oe) significantly affect the spatial distribution of the twin structure producing an effect similar to external stresses.
Novel Iron-Based Superconductor Ca0.5Sm0.5FeAsF Pervakov, K. S.; Kulikova, L. F.; Tsvetkov, A. Yu ...
Bulletin of the Lebedev Physics Institute,
08/2022, Letnik:
49, Številka:
8
Journal Article
Recenzirano
Polycrystalline samples of a novel iron-based 1111-type superconductor Ca
0.5
Sm
0.5
FeAsF are synthesized in an argon atmosphere at a pressure of 50 kbar. This superconducting compound was obtained ...for the first time. The superconducting transition onset temperature of synthesized samples is 54.2 K, which brings the novel compound in line with the highest-temperature ones among all known iron-based superconductors SmFeAs(F,O), GdFeAs(F,O).
Materials with strong susceptibility with respect to the electromagnetic field, namely, ferroelectric (FE) and ferromagnetic (FM) materials are of great interest for modern electronics. On the basis ...of ferroelectrics, devices such as varicades, delay lines, phase shifters, etc. are being actively developed. Ferromagnets (primarily ferrites) serve as the basis for directional couplers, circulators, valves, filters, phased antenna arrays, etc. Today, the most common method of creating functional composites, combining dielectric and magnetic properties, is the introduction of classical ferroelectrics, such as triglycine sulfate, Siegnette salt (KNaC4H4O6∙4H2O), sodium nitrite, etc. in iron-containing matrices. The relevance of this approach is due to the fact that when a ferroelectric is introduced into the FM matrix, it becomes possible to create composite multiferroic materials with two types of ordering (electric and magnetic). In this paper, we study the possibilities of creating glass-ceramic multiferroic materials based on Siegnette salt and barium titanate, introduced in the pore space of ferromagnetic glass, formed by ion exchange between alkaline glass cations and salt melt. For obtaining porous glass-ceramic materials by the method of ion exchange, potassium iron-containing silicate glasses are used in the work. 15K2O·20Fe2O3·55SiO2, mol. % (KFeSi).
Aside from its economic value, davidite and its synthetic analogs may have potential applications in materials science. The unique properties of the crichtonite group minerals, including ...davidite-(La), make them attractive candidates for high-level waste (HLW) immobilization. We studied the thermal evolution of the metamict davidite-(La) from the Radium Hill, Australia. The investigation of the temperature-induced crystallization process was conducted, and the thermal expansion coefficients (TEC) for the recrystallized davidite (RD) were determined for the first time. Our results demonstrate that RD has relatively low TEC indicating its thermophysical stability. The following TECs of davidite- (La) for the temperature range 25–1200 °C were obtained:
α
¯
a
=
α
¯
b
= 9.96 (3) × 10
–6
ºC
−1
;
α
¯
c
= 10.79 (4) × 10
–6
ºC
−1
. The character of the thermal expansion is in agreement with the structure characterized by layers stacked along the
c
axis. The volume TEC α
V
= 24.81 (47)—36.80 (48) × 10
–6
ºC
−1
. Davidite-(La) exhibits an almost isotropic thermal expansion and shows one of the most superior thermal performances in comparison to the other mineral-like phases utilized for the immobilization of HLW.
The metamict fergusonite-(Y) with the formula (Y
0.70
Ln
0.20
Ca
0.13
U
0.02
Th
0.02
)
∑1.07
(Nb
0.72
Ta
0.17
W
0.06
Ti
0.04
)
∑1
(O
3.97
(OH)
0.11
F
0.08
Cl
0.03
) · 2.12H
2
O from the Blyumovskaya ...Pit, Ilmeny Mountains (Russia) was studied by the means of high-temperature X-ray diffraction, thermal analysis, Raman spectroscopy and microprobe analysis. Thermal expansion was studied for both tetragonal (
α
-fergusonite) and monoclinic (
β
-fergusonite) polymorphs. The expansion of
β
-fergusonite is anisotropic and strongly negative along the
α
33
. In contrast,
α
-fergusonite exhibits a relatively isotropic thermal expansion upon heating. The volume CTE (
α
V
) for
β
-fergusonite varies in the range 22.87(94)–75.4(2.5) × 10
–6
ºC
−1
, whereas
α
-fergusonite has
α
V
= 32.33(57)–31.66(49) × 10
-
6
ºC
−1
in the temperature range 850–1200 °C. After heating to 1100 °C, the mineral develops a porous texture, and the radioactivity is reduced by 37%, which can be attributed to the partial volatilization of some radionuclides. In situ experiments revealed the complete sequence of the thermal evolution of the metamict fergusonite-(Y) for the first time.
Multiband superconductivity in KCa2Fe4As4F2 Sadakov, A. V; Gippius, A. A; Daniyarkhodzhaev, A. T ...
Pisʹma v žurnal êksperimentalʹnoj i teoretičeskoj fiziki,
12/2024, Letnik:
119, Številka:
1-2
Journal Article
PDF
