The production of unstable particles on different nuclei provides the possibility to determine the total cross section of the interaction of vector mesons
V
=
ρ
,
ω
,
φ
,
K
∗
0
(
892
)
,
J
/
ψ
etc. ...with nucleons. This interaction is defined by a set of amplitudes that correspond to the transverse (helicity
λ
=
±
1
) or longitudinal (
λ
=
0
) polarization of the vector meson. The total cross section for the interaction of transversely polarized vector mesons with nucleon
σ
T
=
σ
(
V
T
N
)
has been extracted from the coherent photoproduction of vector mesons off nuclei, while the vector meson production in charge exchange reactions as
π
±
(
K
±
)
+
A
→
V
0
(
K
∗
0
)
+
A
′
provides the unique opportunity to obtain the not yet measured total cross section for longitudinally polarized vector meson interacting with nucleon
σ
L
=
σ
(
V
L
N
)
. We shortly discuss the importance of the knowledge of
σ
L
and possibility to extract its value from experiments on nuclear target.
Go-carting vehicles with electric drive Guskov, A
IOP conference series. Materials Science and Engineering,
09/2020, Letnik:
918, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The article describes a number of technical solutions that made it possible to develop Russia's first electric car for domestic go-cart racing, with a power reserve of 40 minutes of active driving, ...acceleration from 0 to 60 km / h in 9.5 seconds, with the ability to reverse, with functions energy recovery during braking. As battery cells, lithium-iron-phosphate cells were used. The article provides a calculation of the optimal battery capacity, based on the requirements for the mass-overall performance of the machine. The results of test runs of a serial model of cars with a power of 5 and 10 kW are presented. The calculations of the economic payback of a go-cart club equipped with electric traction machines are presented. The E-Cart, developed by teachers and undergraduates of the Department of "Automated electric drive" of the South Ural state University, has high performance characteristics. The technical solutions made it possible to achieve high acceleration dynamics and a range of 30 km. on a single charge, the "evenness" of the machines-the range of speed and torque when the battery charge level is from 15 to 100%.
Mycobacterium tuberculosis (Mtb) is an obligate human pathogen and the causative agent of tuberculosis
. Although Mtb can synthesize vitamin B
(cobalamin) de novo, uptake of cobalamin has been linked ...to pathogenesis of tuberculosis
. Mtb does not encode any characterized cobalamin transporter
; however, the gene rv1819c was found to be essential for uptake of cobalamin
. This result is difficult to reconcile with the original annotation of Rv1819c as a protein implicated in the transport of antimicrobial peptides such as bleomycin
. In addition, uptake of cobalamin seems inconsistent with the amino acid sequence, which suggests that Rv1819c has a bacterial ATP-binding cassette (ABC)-exporter fold
. Here, we present structures of Rv1819c, which reveal that the protein indeed contains the ABC-exporter fold, as well as a large water-filled cavity of about 7,700 Å
, which enables the protein to transport the unrelated hydrophilic compounds bleomycin and cobalamin. On the basis of these structures, we propose that Rv1819c is a multi-solute transporter for hydrophilic molecules, analogous to the multidrug exporters of the ABC transporter family, which pump out structurally diverse hydrophobic compounds from cells
.
Monoclinic M′-orthotantalate thulium samples were obtain by co-precipitation and annealing at 1873 K and characterized by X-ray powder diffraction, scanning electron microscopy and chemical analysis. ...Using the high-temperature X-ray diffraction method, the temperature dependences of the monoclinic lattice parameters were determined at range 298–1273 K and instantaneous βV(i) and relative βV(r) volume expansion coefficients were calculated. The molar heat capacity of M′-TmTaO4 was measured by relaxation (4.1–25.1 K), adiabatic (5.6–348.8 K) and differential scanning (303–1333 K) calorimetry. Standard thermodynamic function (entropy, enthalpy increment and reduced Gibbs energy) were calculated on the smoothed values of molar capacity, without taking into account the contribution of phase transformations occurring below 4 K. The general shape of the anomalous Schottky contribution to the molar heat capacity was determined.
Display omitted
•M‘-TmTaO4 synthesis was carried out by coprecipitation and calcination at 1873 K.•Thermal expansion of M‘-TmTaO4 was measured by HTXRD at 298–1273 K.•Heat capacity of M‘-TmTaO4 was measured by relaxation, adiabatic and differential scanning calorimetry 4–1333 K.•Thermodynamic functions M‘-TmTaO4 were calculated.
Gadolinium hafnate samples were obtained by co-precipitation and precursor annealing at a temperature of ~1773 K and characterised by X-ray powder diffraction, scanning electron microscopy and ...chemical analysis. The molar heat capacity of Gd2Hf2O7 ceramics with a pyrochlore structure was measured by adiabatic (8–340 K) and differential scanning calorimetry (315–1345 K). The heat capacity of gadolinium hafnate was extrapolated to 0 K without taking into account anomalies in the temperature range below 20 K. Standard thermodynamic functions were calculated based on the smoothed values of molar heat capacity: entropy, enthalpy change and reduced Gibbs energy. Using the high-temperature X-ray diffraction method, the temperature dependence of the Gd2Hf2O7 cubic crystal lattice parameter was determined in the range of 298–1273 K and coefficients of instantaneous (αi), relative (αr) and linear thermal expansion (TE) were calculated.
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This article presents a concept of a research performance monitoring system. The following models are developed, described, and introduced: a set-theoretic model that includes three logical ...layers—organization, information, and function; an information model that details the content of the information layer of the semiotic model; and a function model of the system for scientometric monitoring of research performance, based on the principles of automation, identification, reliability, reproducibility, verification, and indicator variability and reusability, as well as the FAIR methodological principles for scientific data exchange. It is demonstrated that the proposed conceptual model is in line with current trends in the development of global research communication, and its implementation would create a number of positive technological and economic effects for Russian science.
Monoclinic dysprosium orthotantalate ceramics were synthesised by reverse co-precipitation followed by annealing at 1773 K and characterized by X-ray powder diffraction, scanning electron microscopy ...and chemical analysis. High-temperature X-ray diffraction was used to study change in the lattice parameters in the temperature range of 298–1273 K, and the volume expansion of M-DyTaO4 ceramics was calculated. The molar heat capacity of M-DyTaO4 was measured by adiabatic (9–346 K) and differential scanning (316–1336 K) calorimetries. The temperature dependences of entropy, enthalpy change and reduced Gibbs energy of M-DyTaO4 in the range of 0–1273 K were calculated based on smoothed heat capacity values, without taking into account the contribution of phase transformations occurring below 9 K. The general shape of the anomalous Schottky contribution to the molar heat capacity was determined.
The Spin Physics Detector (SPD) is a future multipurpose experiment foreseen to run at the NICA collider, which is currently under construction at the Joint Institute for Nuclear Research (JINR, ...Dubna, Russia). The physics program of the experiment is based on collisions of longitudinally and transversely polarized protons and deuterons at s up to 27 GeV and luminosity up to 1032 cm−2 s−1. SPD will operate as a universal facility for the comprehensive study of the unpolarized and polarized gluon content of the nucleon, using complementary probes such as: charmonia, open-charm, and prompt-photon production processes.
The aim of this work is to provide a thorough review of the physics objectives that can potentially be addressed at SPD, underlining related theoretical aspects and discussing relevant experimental results when available. Among different pertinent phenomena particular attention is drawn to the study of the gluon helicity, gluon Sivers and Boer-Mulders functions in the nucleon, as well as the gluon transversity distribution in the deuteron, via the measurement of single and double spin asymmetries.
Uptake of vitamin B12 is essential for many prokaryotes, but in most cases the membrane proteins involved are yet to be identified. We present the biochemical characterization and high-resolution ...crystal structure of BtuM, a predicted bacterial vitamin B12 uptake system. BtuM binds vitamin B12 in its base-off conformation, with a cysteine residue as axial ligand of the corrin cobalt ion. Spectroscopic analysis indicates that the unusual thiolate coordination allows for decyanation of vitamin B12. Chemical modification of the substrate is a property other characterized vitamin B12-transport proteins do not exhibit.
—
Praseodymium hafnate (Pr
2
Hf
2
O
7
) powder with the pyrochlore structure has been synthesized and characterized by X-ray diffraction, scanning electron microscopy, and chemical analysis. Its ...molar heat capacity has been determined in the temperature range 315–1345 K and its lattice parameter has been measured as a function of temperature in the range 298–1273 K.
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