Electromagnetic dissociation of $^{197}$Au at NICA
Electromagnetic dissociation of $^{197}$Au at NICA
U. A. Dmitrieva$^{1,2}$
Collisions of $^{197}$Au nuclei with center-of-mass energy $\sqrt{s_ {NN}}$ from 4 to 11 GeV will be studied by means of the MPD (MultiPurpose Detector) at the NICA collider, which is presently under construction. The MPD experiment is focused on high-density strongly interacting nuclear matter created in the region of overlap of colliding nuclei. However, there are no publications that quantitatively characterize the long-range impact of the Coulomb fields of nuclei on collision partners in the so-called ultraperipheral collisions at NICA with impact parameters exceeding the sum of the nuclear radii. In this paper, the total cross sections of electromagnetic dissociation (EMD), multiplicities of secondary particles and the production cross sections of secondary nuclei resulting from ultraperipheral collisions of $^{197}$ Au nuclei at NICA are calculated by means of RELDIS (Relativistic ELectromagnetic DISsociation) model. The obtained results can be used to assess the impact of secondary particles and nuclei on the collider components.
Show AbstractContribution of magnetar burst pulsed emission to X-ray detectability of fast radio burst counterparts
Contribution of magnetar burst pulsed emission to X-ray detectability of fast radio burst counterparts
A. D. Khokhriakova$^1$, S. B. Popov$^{1,2}$
In this note we discuss the possibility of detecting accompanying X-ray emission from sources of fast radio bursts with the eROSITA telescope onboard the Spektr-RG observatory. In the previous paper we have shown that during the four years of the survey program about 300 bursts are expected to appear in the field of view of eROSITA. About 1\% of them will be detected by ground based radio telescopes. For the total energy release $\sim~10^{46}$~ergs depending on spectral characteristics and absorption in the interstellar and intergalactic media, an X-ray flare can be detected from distances from $\sim 1$~Mpc (thermal spectrum with $kT=200$~keV and strong absorption) up to $\sim1$~Gpc (power-law spectrum with photon index $\Gamma=2 $ and realistic absorption). In this paper, we refine the model of hyperflares by adding to the main pulse a so-called ``pulsating tail" whose radiation has a relatively soft thermal spectrum ($kT=10$ keV), and the total energy release is $\sim 10^{44}$~erg. This supplement allows to significantly increase the maximum distance at which a burst is registered for some parameters of the flares. Thus, eROSITA observations might help to provide important constraints on parameters of sources of fast radio bursts, or may even allow identification of X-ray transient counterparts, which will help to constrain models of fast radio bursts generation.
Show AbstractChange of luminescent properties of pyrene in surface-active substance solution using an albumin
Change of luminescent properties of pyrene in surface-active substance solution using an albumin
S. R. Sokolnikova, D. A. Tatarinov, N. A. Myslitskaya
The aim of this work is to research luminescent properties of the representative of polycyclic aromatic hydrocarbons – pyrene in micellar solution, formed by molecules of anionic surfactant – dioctylsulfosuccinate sodium. The increase of luminescent emission of pyrene explained with solubilization of molecules of polycyclic aromatic hydrocarbons in micelle structures was recorded. The dipole - dipole transfer of energy on Ferstera (FRET) where an acceptor is pyrene, and the donor is a bull albumin is studied. The average size of micelles of a surface-active substance and aggregation number at concentration of micellar solution of 0.001 M is calculated
Show AbstractNumerical study of combustion of fuel particles in burning with the introduction of the secondary fuel
Numerical study of combustion of fuel particles in burning with the introduction of the secondary fuel
M. A. Khabarova, A. A. Trinchenko
Energy is the Foundation for the development and existence of the industrial sector of any country. At present, a significant share in the generation of electricity is coal generation, an important indicator of which is the ecology of production. The estimated reduction of adverse impact of the operation coal-fired power plants on the environment during the application of the technology stage solid fuel burning polyfractional composition. Based on the numerical study of the combustion process, the effect of the introduction of this technology in a steam power boiler with flaring technology is estimated. According to the developed approaches are identified: the level of flue gas temperatures in the furnace chamber height, with the launch of the secondary fuel; indicators of the combustion process at various stages; the trajectory of the particles of burning coal particles; dynamics of changes in the concentration of nitrogen oxides at the height of the furnace, the mechanical incomplete combustion of the fuel and specified values of indicators of efficiency of operation. According to the diffusion-kinetic theory of the combustion modern approaches developed an algorithm, a mathematical model and a computer program for calculating the combustion process of coal fuel of the polyfractional composition taking into account the input of secondary fuel. The model takes into account complex physical and chemical transformations occurring in the process of burning coal fuel, and can be used at the design stage of new installations and upgrading of existing boiler units.
Show AbstractSingle-nucleon transfer reactions on sulfur isotopes
Single-nucleon transfer reactions on sulfur isotopes
I. D. Dashkov$^2$, T. Yu. Tretyakova$^1$, N. A. Fedorov$^3$
Based on the experimental data of the single-nucleon transfer reactions, the energies and occupation probabilities of proton single-particle states in $1d2s$ shell in stable sulfur isotopes $^{32}$S and $^{34}$S are estimated. The use of the most complete and up-to-date experimental data made it possible to clarify the structure of the proton states and to determine the main trends of its change with the addition of a pair of neutrons.
Show AbstractMagnetic properties of three-layer thin-film systems based on cobalt with an intermediate layer of gadolinium
Magnetic properties of three-layer thin-film systems based on cobalt with an intermediate layer of gadolinium
A. M. Kharlamova$^1$, E. E. Shalygina$^2$, S. L. Efremova$^3$, A. V. Svalov$^4$
The results of the investigation of the structural and magnetic characteristics of thin-film Co/Gd/Co systems obtained by the method of ion-plasma magnetron sputtering are presented. The thickness of the Co layers was 5.0 nm, and the Gd one varied from 0.5 to 10.0 nm. It was found that the magnetic-field behavior of the studied samples depends on the thickness of the Gd layer, tGd. In particular, the saturation field, HS, oscillates in magnitude with increasing the Gd layer thickness. This fact was explained by the influence of the magnetostatic interaction between the magnetic layers due to the difference of the coercive force values of the upper and lower Co layers and also by the changes of the direct exchange and magnetostatic interactions between the Co layers with a variation of the Gd layer thickness.
Show AbstractNew Aspects of 2D Correlation Relaxometry in NMR
New Aspects of 2D Correlation Relaxometry in NMR
E. I. Uskova, M. M. Dorogynitsky, V. D. Skirda
Various aspects of the method of two-dimensional (2D) NMR relaxometry in terms of the isolation and identification of dynamic phases are considered. The dispersion dependences of the nuclear magnetic relaxation times on the correlation time $\tau_c$ and the second moment $\Delta\omega^2$ are analyzed. The correlation time $\tau_c$ is determined from the autocorrelation function of the Hamiltonian of the spin interaction with its environment and characterizes the intensity of the stochastic motion of molecules. The second moment $\Delta\omega^2$ is interpreted depending on the proposed mechanism of nuclear magnetic relaxation and contains information about the structure of the system under study. A new method for calculating the joint distribution of correlation times $\tau_c$ and second moments $\Delta\omega^2$ is given. To obtain a joint distribution of the correlation times $\tau_c$ and the second moments of ${P}_{2}(\tau_c, \Delta \omega^2)$, Tikhonov regularization method is used with the introduction of a priori information about the non-negativity and 0-smoothness of the solution, as well as the preferential mechanism of nuclear magnetic relaxation in the system under study. The field of application of the technique is the study of slow molecular motions that meet the condition of the ratio of the spin-lattice relaxation time $T_1$ to the spin-spin relaxation time $T_2$: $T_1 /{T}_2 > 1.125$. In contrast to the well-known methods for calculating 2D maps of the joint distribution ${P}_{2}(T_1 , T_2)$, the proposed method for constructing a 2D map of the joint distribution ${P}_{2}(\tau_c, \Delta \omega^2)$ does not depend on the main characteristic of the NMR relaxometer~--- the resonance frequency $\omega_0$, that allows us to compare data obtained by various devices. The technique was used to analyze the characteristics of sorbed water in clay rocks~--- argillite.
Show AbstractInvestigation of the helium trimer via Faddeev differential equations
Investigation of the helium trimer via Faddeev differential equations
A. A. Korobitsin$^1$, E. A. Kolganova$^{1,2}$
Properties of the helium trimer $^4$He$_3$ are studied using the Faddeev differential equations. The spectrum of the helium trimer is calculated using different realistic forces. The influence assessment of modern potential models on the properties of the three-particle system is done.
Show AbstractInvestigation of the vector-phase structure of the sound field at the hydroacoustic polygon of Moscow State University for the purposes of passive tomography
Investigation of the vector-phase structure of the sound field at the hydroacoustic polygon of Moscow State University for the purposes of passive tomography
E. V. Medvedeva$^1$, B. I. Goncharenko$^1$, A. S. Shurup$^{1,2,3}$
The results of field measurements data processing of the sound field vector-phase structure are presented. The data was obtained during the experiment at the hydroacoustic polygon of Moscow State University in the summer of 2018, in which two separated in space combined receiving modules, containing a sound pressure receiver and a vector receiver, have recorded a noise field in the presence of an active shipping. On the basis of synchronized pressure recordings and three mutually orthogonal projections of the oscillatory velocity, the spatial anisotropy and decay of the noise field are estimated. Additionally, the bearing values for the passing vessel as a sound source are estimated. The obtained results are used for experimental approbation of the algorithm, which allows to reconstruct the mutual orientation of the vector receiver channels installed at the bottom of the water area in different geographical points. The proposed approach allows us to simplify the technical side of conducting experiments with spaced combined receiver modules, since it does not require additional procedures to control the orientation of the vector receiver channels when they are installed on the bottom of the water area. The results obtained can be used in constructing the schemes of passive tomography of shallow seas, with simplified requirements for their practical implementation.
Show AbstractPassive tomography of shallow water based on the phase of the cross-correlation function of noise
Passive tomography of shallow water based on the phase of the cross-correlation function of noise
I. R. Sabirov$^1$, A. S. Shurup$^{1,2,3}$
The possibilities and limitations of using information about the phase of the cross-correlation function of noise signals recorded in spatially separated points of the water area for the purposes of passive tomography of the shallow sea are discussed. In the framework of numerical simulation, the presence of characteristic features of the phase of the Green function near the critical frequencies of hydroacoustic modes is demonstrated. It is revealed that at these frequencies the derivative of the phase has a discontinuity, which can be used as a criterion for estimating the critical frequencies of the waveguide modes. A scheme for reconstructing waveguide characteristics from data in the form of a phase of the mutual correlation function of the noise field and critical frequencies of sonar modes is proposed and implemented numerically. It is shown that taking into account the values of critical frequencies as additional information in the inverse problem solving improves the accuracy of the reconstruction of the waveguide parameters and the noise immunity of the proposed algorithm.
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