A device for controlling a two-winding polarized electromagnet is considered, and its disadvantages are noted. A circuit for the control of a single-winding polarized electromagnet is proposed in ...which the disadvantages of the existing control circuit are eliminated. Transient processes of charge/discharge of a capacitor to ensure actuation and reset of a polarized electromagnet are considered. The operability of the proposed circuit based on a composite transistor has been experimentally confirmed.
We study the inclusive J/ψ production in proton–nucleus collisions in the near-threshold energy region within the spectral function approach for incoherent primary proton–nucleon charmonium ...production. Our approach takes into account the effect of the nuclear J/ψ mean-field potential on these processes, as well as the elementary final state interaction (FSI) between the outgoing nucleons participating in them. We calculate the momentum dependence of the various J/ψ observables (transparency ratio, absolute and relative charmonium yields) as well as the total cross section for J/ψ production in pC, pW and pAu interactions at incident proton kinetic energies of 8, 11 and 23 GeV within the different scenarios for the J/ψ in-medium modification. We show that the transparency ratio for J/ψ mesons has an insignificant sensitivity to the J/ψ in-medium mass shift at these energies. On the other hand, our studies demonstrate that the momentum distributions (absolute and relative) for low momentum J/ψ near-threshold production in pA reactions have distinct sensitivity to the J/ψ in-medium modification. Therefore, the measurement of such observables in the CBM experiment at FAIR in the near-threshold energy domain will allow to study the modification of the charmonium properties in the nuclear medium.
Abstract
The results of the development of a universal control circuit for a triggering polarized electromagnet for a low voltage vacuum contactor are presented. The circuit is implemented in the ...form of a printed wiring block and is unified with an element base with a control circuit for the KV2-160, KV2-250 vacuum contactors commercially produced by the domestic industry. The developed design of an electromagnetic drive with magnetic memory based on high-coercive permanent magnets is described. The working cycle of an electromagnet with a ferromagnetic shunt for the implementation of a manual return unit for the purpose of its use in emergency or necessary technological modes is considered. A block for manual return of contacts of a vacuum contactor using an eccentric transmission has been developed and implemented, which makes it possible to significantly reduce the effort of manual operation when returning the shunt to its original position for the operation of the contactor in normal mode. The classical graphical-analytical method for calculating magnetic circuits with permanent magnets has been modernized. The fundamentals of the modernized method for calculating magnetic circuits with permanent magnets are considered. The positive results of approbation of the developed calculation methods, which were implemented in the development of a vacuum contactor with magnetic memory and the function of manual return of the electromagnet armature and opening of the main contacts for the serial production of contactors, are noted.
This paper considers an original valve electromagnet with integrated armature, designed to implement an electromagnetic overcurrent release of a circuit breaker. Theoretical and experimental studies ...of the proposed electromagnet have been carried out to determine the most important parameters of circuit breakers such as sensitivity and high-speed performance. Calculations and experiments have shown the possibility of increasing the sensitivity and speed of the electromagnetic overcurrent release based on the proposed electromagnet with integrated armature in comparison with existing structures used in modern circuit breakers.
Thermal releases based on thermobimetallic elements (TBEs) form the current-dependent part of the protective characteristic of a circuit breaker. The design of a mechanism of free releasing and the ...characteristics of a thermobimetallic element are analyzed. The operating condition for the thermal release is formulated, which is based on comparison of the mechanical characteristics of an actuator and thermomechanical characteristic of TBEs. Experimental studies of thermobimetallic releases, which are analogues of the breakers to be developed, were carried out. Taking into account the results of these experiments, a design procedure of thermobimetallic release was developed, which is applicable for all types of TBE heating (direct, indirect, combined). The procedure makes it possible to determine the geometrical dimensions of a TBE and the methods of its heating, as well as the operating temperature of release depending on the rated current of the breaker. It has been noted that, to provide the possibility of operating current adjusting, as well as for reliable operation of circuit breakers under vibration and shock conditions, it is necessary to provide for the free running of TBE during design. Comparison of design and experimental data showed the accuracy of procedure, which is acceptable for practical calculations.
This paper presents the results of the investigation of Ge1-xSnx epitaxial layers grown by the hot wire chemical vapor deposition (HW CVD) method with simultaneous evaporation of Sn from a standard ...effusion cell. The Ge1-xSnx with a Sn molar fraction of 7.2% and a full width at half maximum (FWHM) of the rocking curve of 7.6` demonstrated intense photoluminescence at room temperature. The peaks in the energy bands 0.70 - 0.73 eV and 0.63 - 0.65 eV have been observed in the photoluminescence spectra. These peaks were related to the direct and indirect interband radiative optical transitions in GeSn, respectively.
Compensators of the repulsive electrodynamic forces of electrical contacts provide stable operation of automatic switches during the flow of short-circuit currents. This paper presents a contact ...device with electrodynamic compensation and its design model. The electrodynamically interacting parts of the compensator structure are the U-shaped bent ends of the current-carrying output tire and slow-moving contacts parallel to each other. The formula for calculating the repulsive electrodynamic force of electrical contacts is given. On the basis of the calculation model, the formulas for the electrodynamic effort of the compensator and expressions for contour coefficient of electrodynamic forces of compensator have been obtained. The condition of complete compensation of the repulsive electrodynamic force of contacts is presented. Calculations of the electrodynamic effort of the compensator of the breaker for a rated current of 630 А with a rated short-time withstand current of 40 kA have been performed. The compensator with the proposed configuration fully compensates for the electrodynamic repulsive force of contacts of circuit breaker, confirming the validity of relations obtained in the work.
The radiation-frequency locking by an external signal is experimentally studied for a megawatt gyrotron. An external signal from a magnetron is applied to the operation space of the gyrotron at a ...frequency of 35 GHz via a synthesized two-mirror quasioptical converter developed at the Institute of Applied Physics of the Russian Academy of Sciences. The radiation spectra are measured for both the frequency locking regime and the frequency beats. The locking region is constructed on the plane of two parameters, namely, the external-signal power and frequency. The experimental and theoretical results are compared to show a good agreement.
We present a measurement of the pion form factor based on e+e− annihilation data from the CMD-2 detector in the energy range 0.6<s<1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five ...times larger than that used in our previous measurement.
Rice crop residues are one of the recalcitrant agricultural wastes in arid conditions. A laboratory experiment was conducted to decompose rice straw with woodlice and millipedes living in the dry ...steppes of Kalmykia in Russia. Five individuals of two species of woodlice (
Armadillidium vulgare
and
Protracheoniscus kryszanovskii
) or two species of millipedes (
Brachydesmus assimilis
and
Cylindroiulus
sp.) were placed in microcosms with soil and 2.5 g of rice straw. The straw mass significantly decreased for all species, by approximately 50% on average for the 4 months of the experiment. The content of organic matter in the soil before and after the experiment did not change significantly, which suggests that the selected species of woodlice and millipedes can consume and, thus utilize, rice straw, at least under experimental conditions.
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