699 research outputs found
INCREASING THE LEVEL OF PHYSICAL AND MECHANICAL PROPERTIES OF COLD-ROLLED STEEL OF THE BRAND DC01 IN ORDER TO ENSURE ITS REQUIREMENTS EN 10130 IN THE CONDITIONS OF PJSC "ZAPORIZHSTAL"
Increasing the level of physical and mechanical properties of cold-
rolled steel
On the theory of resonant susceptibility of dielectric glasses in magnetic field
The anomalous magnetic field dependence of dielectric properties of
insulating glasses in the temperature interval is considered. In
this temperature range, the dielectric permittivity is defined by the resonant
contribution of tunneling systems. The external magnetic field regulates
nuclear spins of tunneling atoms. This regulation suppresses a nuclear
quadrupole interaction of these spins with lattice and, thus, affects the
dielectric response of tunneling systems. It is demonstrated that in the
absence of an external magnetic field the nuclear quadrupole interaction
results in the correction to the permittivity in the
temperature range of interest. An application of a magnetic field results in a
sharp increase of this correction approximately by a factor of two when the
Zeeman splitting approaches the order of . Further increase of the
magnetic field results in a relatively smooth decrease in the correction until
the Zeeman splitting approaches the temperature. This smooth dependence results
from tunneling accompanied by a change of the nuclear spin projection. As the
magnetic field surpasses the temperature, the correction vanishes. The results
obtained in this paper are compared with experiment. A new mechanism of the low
temperature nuclear spin-lattice relaxation in glasses is considered.Comment: 9 Pages, 5 Figures, To be submitted to the Physical Review B, please
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Effect of nuclear quadrupole interactions on the dynamics of two-level systems in glasses
The standard tunneling model describes quite satisfactorily the thermal
properties of amorphous solids at temperatures in terms of an ensemble
of two-level systems possessing logarithmically uniform distribution over their
tunneling amplitudes and uniform distribution over their asymmetry energies. In
particular, this distribution explains the observable logarithmic temperature
dependence of the dielectric constant. Yet, experiments have shown that at
ultralow temperatures such a temperature behavior breaks down and the
dielectric constant becomes temperature independent (plateau effect). In this
letter we suggest an explanation of this behavior exploiting the effect of the
nuclear quadrupole interaction on tunneling. We show that below a temperature
corresponding to the characteristic energy of the nuclear quadrupole
interaction the effective tunneling amplitude is reduced by a small overlap
factor of the nuclear quadrupole ground states in the left and right potential
wells of the tunneling system. It is just this reduction that explains the
plateau effect . We predict that the application of a sufficiently large
magnetic field should restore the logarithmic dependence because of the
suppression of the nuclear quadrupole interaction.Comment: To appear in the Physical Review Letter
Influência da temperatura e do substrato na germinação de sementes de dedaleiro (Lafoensia pacari).
Resumo
Approximate calculation of the basic parameters of energodinamic processes starting and stopping planetary drive
The paper presents a simplified engineering method, which at the stage of conceptual design allows you to define the parameters of the preliminary processes starting and stopping of the planetary drive. Introduction of the proposed simplifications, gives an opportunity to solve a differential equation of motion of the inertial elements of the dynamic model of the drive.В статье представлена упрощенная инженерная методика, которая на стадии эскизного проектирования позволяет определять предварительные параметры процессов включения и остановки планетарного привода. Введение предложенных упрощений дает возможность решить дифференциальное уравнение движения инерционных элементов динамической модели привода
Efeito do substrato e da temperatura na germinação de sementes de Escallonia montevidensis (Cham. & Schl.) DC. (Saxifragaceae).
Organizado por Patricia Póvoa de Mattos, Celso Garcia Auer, Rejane Stumpf Sberze, Katia Regina Pichelli e Paulo César Botosso
Thermoelectric behavior of BaZr0.9Y0.1O3−d proton conducting electrolyte
BaZr0.9Y0.1O3-δ (BZY10), a promising proton conducting material, exhibits p-type conduction under oxidative conditions. Holes in BZY10 are of the small polaron type. However, there is no clear understanding at which places in the lattice they are localized. The main objectives of this work were, therefore, to discuss the nature of electronic defects in BZY10 on the basis of the combined measurements of the thermo-EMF and conductivity. Total electrical conductivity and Seebeck coefficient of BZY10 were simultaneously studied depending on partial pressures of oxygen (pO2), water (pH2O) and temperature (T). The model equation for total conductivity and Seebeck coefficient derived on the basis of the proposed defect chemical approach was successfully fitted to the experimental data. Transference numbers of all the charge carriers in BZY10 were calculated. The heat of transport of oxide ions was found to be about one half the activation energy of their mobility, while that of protons was almost equal to the activation energy of their mobility. The results of the Seebeck coefficient modeling indicate that cation impurities, rather than oxygen sites, should be considered as a place of hole localization. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 18-73-00022Funding: This work was supported by the Russian Science Foundation (project No. 18-73-00022
Rehabilitation of athletes’ after Achilles tendon surgery
Frequency of Achilles tendon injury increases. The lack of standardized methods of rehabilitation after surgery on the Achilles tendon leads to increased risk of repeated injury of tendon and reduces the possibility of coming round to physical activity. Recovery of function is the main task of rehabilitation programs, especially in athletes. This article sets out the basic principles of remedial actions. It can be used with patients of different levels of physical activity and it can be modified according to the task performed and features of surgical treatment in order to achieve optimal results
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