The mechanical and structural properties of cement compounds containing a simulator of high-level radioactive waste were examined after exposure to electrons and α-particles up to the absorbed dose 1 ...GGy and 10
19
decays/yr, respectively. It is shown that the phase composition and surface morphology of the cement samples do not change significantly and the strength remains acceptable.
To efficiently utilize ultra-short range wireless technologies providing extreme data rates at the air interface, the concept of "information shower" (IS) has been proposed to complement typical ...small cell deployments. Although the concept was introduced several years ago, the benefits of ISs is still an open question. We propose an analytical framework for performance evaluation of ISs operating in the terahertz (THz) frequency band. Taking into account different THz bandwidth allocations resulting in different IS coverages and capacities and assuming applications capable of data prefetching, we estimate both user- and network-centric metrics as a function of input parameters including mobility of users. Our study reveals that initiating heavy traffic sessions upon entering THz ISs allows to offload up to 95% of traffic from long-range networks even for low IS sizes and high user densities as the THz IS data rates efficiently compensates for large inter-IS visit times. Such massive offloading also results in considerable improvements in mobile terminal energy efficiency as the fraction of time the radio interfaces have to be active drastically decreases.
Based on the data of thermogravimetric analysis the values of the oxygen index (3-δ) in the manganite of the La
0.7
Sr
0.3
Mn
0.9
Fe
0.1
O
3-δ
composition, obtained by solid-phase reaction technique, ...have been calculated. The analysis of oxygen sorption-desorption curves showed that the processes of oxygen release and absorption at
p
O
2
= 10 Pa and
p
O
2
= 400 Pa are not reversible. The minima of the derivative dδ/d
t
=
f
(
T
) corresponding to the maxima of the oxygen extraction rate indicate the complex character of changes in the oxygen desorption rate from manganite. The decrease in the heating and cooling rate from 6.6 K/min to 2.6 K/min resulted in a significant change in the value ∆δ, indicating the dependence of anion mobility on the oxygen concentration in the magnet structure. It has been revealed that in the La
0.7
Sr
0.3
Mn
0.9
Fe
0.1
O
3-δ
manganite the oxygen desorption kinetics is well described by the exponential dependence on the Kramers model, which implies no return of desorbed oxygen to the sample. This model indicates the non-stationarity of the diffusion flux through the barrier during desorption of oxygen from samples. The calculation of the activation energy of oxygen desorption by the Merzhanov method at various partial pressures of oxygen has shown that at the initial stage of oxygen extraction from La
0.7
Sr
0.3
Mn
0.9
Fe
0.1
O
3-δ
, the activation energy of oxygen desorption has a minimum value (
Е
а
= 103.7 kJ/mol at δ = 0.005) and as the concentration of oxygen vacancies increases, it rises reaching saturation (
Е
а
= 134.3 kJ/mol at δ = 0.06). It is assumed that with an increase in the concentration of oxygen vacancies, an interaction occurs between them, followed by the processes of their ordering with the formation of associates.
ELECTRONIC STRUCTURE OF DIOXIDE CfO2 Putkov, A. E.; Maslakov, K. I.; Teterin, Yu. A. ...
Journal of structural chemistry,
12/2021, Letnik:
62, Številka:
12
Journal Article
Recenzirano
The electronic structure of CfO
2
is calculated in the fully relativistic cluster approximation of the discrete variation method (RDV). Theoretical X-ray photoelectron spectroscopy (XPS) spectrum of ...valence electrons is obtained in the range of electron binding energies 0 -…~40 eV. It is shown that outer valence molecular orbitals (OVMOs) in the energy range 0 -…~15 eV are formed by atomic orbitals Cf 5
f
and Cf 6
p
. The inner valence molecular orbitals (IVMOs) in the energy range ~15 -…~40 eV are formed mainly by Cf 6
p
3/2
and O 2
s
AOs. Significant covalent effects in CfO
2
are due to the strong overlap of AOs with the ligand′s orbitals such as Cf 6
d
as well as Cf 5
f
and Cf 6
p
. The structure of MOs formed by Cf 6
d
, 7
s
, and 7
p
AOs differs only slightly from those of dioxides of lighter actinides. These MOs, together with those containing O 2
s
and O 2
p
AOs, form a “rigid framework” where MOs containing An 5
f
AOs move. We suggest a theoretical scheme of MOs that allows understanding the nature of chemical bonding and the structure of the XPS spectrum of valence electrons in CfO
2
.
Two-range magnetoelectric sensor Bichurin, M.; Petrov, V.; Leontyev, V. ...
AIP advances,
01/2017, Letnik:
7, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In this study, we present a two-range magnetoelectric ME sensor design comprising of permendur (alloy of Fe-Co-V), nickel, and lead zirconate titanate (PZT) laminate composite. A systematic study was ...conducted to clarify the contribution of magnetostrictive layers variables to the ME response over the applied range of magnetic bias field. The two-range behavior was characterized by opposite sign of the ME response when magnetic dc bias is in different sub-ranges. The ME coefficient as a function of magnetic bias field was found to be dependent on the laminate composite structure.
The (114) surface of the semimetal Bi is found to support a quasi-one-dimensional, metallic surface state. As required by symmetry, the state is degenerate along the Gamma-Y line of the surface ...Brillouin zone with a highest binding energy of approximately 150 meV. In the Gamma-X direction the degeneracy is lifted by the strong spin-orbit splitting in Bi, as directly shown by spin-resolved photoemission. This results in a Fermi contour consisting of two closely separated, parallel lines of opposite spin direction. It is argued that similar states on related insulators would give rise to a one-dimensional quantum spin Hall effect.
The ore-bearing geological structural units of the southern Cis-Argun region are considered in the context of varying geodynamic regimes related to the Proterozoic, Caledonian, and Hercynian ...tectono-magmatic cycles, as well as during the Late Mesozoic within-plate tectono-magmatic activity, which give rise to the formation of subalkaline igneous rocks of the Shakhtama Complex with Au, Cu–Mo, Pb–Zn–Ag metallogenic specialization; volcano-plutonic complexes of calderas with Mo–U, Pb–Zn, and fluorite ores; and rare-metal granite of the Kukulbei Complex with a Sn–W–Li–Ta spectrum of mineralization. The comparative geochemical characteristics inherent to Mesozoic ore-bearing felsic igneous rocks are considered, as well as geodynamic settings of ore-bearing fluido-magmatic systems, taking into consideration new data on geochemistry of bimodal trachybasalt–trachydacite series and rhyolite of the Turga Series, which fill the Strel’tsovka Caldera, whose trend of evolution is defined as a reference for geological history of the studied territory. The geodynamic conditions, phase composition, and geochemistry of rocks along with metallogenic specialization of Mesozoic volcano-plutonic complexes of southern Cis-Argun region are close to those of the Great Khingan Belt in northeastern China and eastern Mongolia.
The hydrothermal molybdenum–uranium deposits of the Streltsovka ore field are localized in a volcanic caldera of Late Mesozoic age. The paper presents the results of numerical modeling of free ...thermal convection of fluids in the residual thermal field of the consolidated magma chamber of the Streltsovka caldera, which justifies the idea of thermoconvective mechanism for the formation of the structurally conjugate Streltsovka and Antei deposits. The process of fluid heat and mass transfer in the Antei–Streltsovka oreforming system self-organized into a convection cell with a fluid circulation circuit including a descending convection branch along the ring-fault zone of the caldera, a lateral flow branch from the descending to the ascending convection branch in the caldera’s basement rocks, an ascending convection branch along faults of the Antei deposit, and a lateral return branch from the ascending to the descending convection branch along the caldera’s volcano-sedimentary rock fill, in which the ores of the Streltsovka deposit are localized. At the same time, formation of the total reserves of the Antei–Streltsovka deposit, largest in this ore field, was facilitated by uranium sourced, during the hydrothermal ore-forming process, not only from the uranium-rich rocks of the consolidated magma chamber, but also from the granitic host rocks of the Streltsovka caldera basement.
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