Narrow-linewidth IR laser modulation by quantum cascade laser structure
Narrow-linewidth IR laser modulation by quantum cascade laser structure
S. A. Chakhlov$^{1,2}$, L. A. Miklashevich$^1$, A. A. Lastovkin$^1$, N. G. Zakharov$^1$
The effect of modulation of narrow-linewidth laser radiation in the 1590 nm range, passed through the waveguide structure of a quantum cascade laser, is obtained, observed when applying an electric voltage to the structure. This effect reveals the thermodynamics of the active region of a quantum cascade laser operating in a pulsed mode, which is relevant in the problem of optical communication implemented on the principle of high-frequency amplitude signal modulation.
Show AbstractWater Formation in Asteroids
Water Formation in Asteroids
A. Yu. Dubinsky$^1$, S. I. Popel$^1$, J. S. Reznichenko$^{1,2}$
The issue of the formation of water molecules in asteroid regolith is considered. The possibility of oxygen atoms release as parts of silver hydroxide molecules from the crystal lattice of silicon dioxide in regolith has been demonstrated. Silver hydroxide, in turn, can react with hydrogen relatively easily, resulting in the formation of water and silver. This demonstrates the possibility of the formation of water molecules included in the near-surface soil of an asteroid. The proposed mechanism for the formation of water molecules does not require such an unlikely event as two solar wind protons hitting the same point. In the situation under consideration, it is only required that the end of the proton track fall in the region where the elements of the quartz lattice, for example, metal sulfide, are in contact with each other. The presence of water molecules in the soil of an asteroid can affect the photoelectric properties of its regolith and the parameters of the plasma-dust system above the asteroid. A way to identify the nature of the formation of water on an asteroid can be a combination of the method of finding water on asteroids, based on the detection of dust near the surfaces of these space objects, as well as a method using the detection of neutron fluxes passing through areas of the surface of the space body.
Show AbstractLight coupling devices for subwavelength waveguides based on second order surfaces manufactured by two-photon laser lithography
Light coupling devices for subwavelength waveguides based on second order surfaces manufactured by two-photon laser lithography
I. O. Batuev$^1$, K. A. Smirnov$^1$, I. I. Tsiniaikin$^2$, A. I. Maydykovskiy$^1$, T. V. Murzina$^1$
Light input/output devices are essential for coupling between bulk and fiber optical devices and photonic integrated circuits (PIC). In this work, broadband couplers for optical waveguides lifted from the surface, were fabricated by two-photon laser lithography, and comparison with numerical modeling was conducted. It was demonstrated experimentally that the ellipsoid-based coupler is optimal for coupling light with the waveguide. Average transmittance of a system of two adapters in the spectral range 700-1000 nm for s-polarized radiation amounted to at least 27%.
Show AbstractNew Approaches to Visualization and Analysis of Flows in Shock Tubes
New Approaches to Visualization and Analysis of Flows in Shock Tubes
D. I. Dolbnia, I. A. Doroshchenko, I. A. Znamenskaya, M. I. Muratov
This paper presents new approaches to studying gas-dynamic processes in shock tubes using modern visualization and analysis methods. The flow behind the shock wave in a rectangular channel of a shock tube of constant cross-section and in a channel with an obstacle was studied. The experiments include the use of high-speed digital shooting, infrared thermography, and a tracing method, which allow analyzing the evolution of the flow in the shock tube with high temporal and spatial resolution. The results showed that the flow in the shock tube channel can be used for research for 20 – 25 milliseconds, which significantly exceeds the previously used time ranges. It is possible to conduct experiments, including studies of heat and mass transfer associated with flow around the walls of the channel, obstacles with the initiation of pulsed discharges in the flow. The results of a study of the evolution of flow parameters are presented. It is shown that the use of machine learning and computer vision methods, including convolutional neural networks, allows efficient processing and analysis of large arrays of data obtained during high-speed recording.
Show AbstractQuantum oscillator as a open system
Quantum oscillator as a open system
A. I. Trubilko
The possibility of using the quantum oscillator model in the theory of open quantum systems is demonstrated by means of algebraic perturbation theory. The case of resonant and non-resonant interactions of two spatially separated oscillators is considered, each of which interacts with its own thermostat at different temperatures. The possibility of decay of an isolated oscillator during its non-resonant interaction into an oscillator-mediator in the environment of the latter is demonstrated. In all the cases presented, algebraic perturbation theory does not lead to any non-physical features or contradictions such as violation of the second law of thermodynamics and discrepancies in the description of these cases within the framework of the global and local approaches
Show AbstractEstimation of possible supersaturation of solutions at ion exchange in porous media.
Estimation of possible supersaturation of solutions at ion exchange in porous media.
N. A. Tikhonov
The phenomenon of isothermal supersaturation of solutions in a porous medium at ion exchange is studied on the basis of mathematical modeling. The phenomenon consists in the fact that the solution with concentration significantly higher than the maximal solubility of the substance is formed in the pores of sorbent and no precipitation occurs. The general nature of the phenomenon has been noted in the works of some authors and an explanation was given for the stability of the supersaturated solution in the micropores of ion exchangers. The question of why sediment does not appear in larger pores remains open. In this paper, a model of changing of the number of condensed phase particles in pores is proposed and estimates are obtained that allow one to determine the degree of possible supersaturation depending on the process parameters. It is shown that the phenomenon under consideration can be explained not by a change in thermodynamic conditions in a porous medium, compared to normal conditions, but by the effect of dynamic equilibrium between the association of condensed phase particles in the inner part of the pores, their diffusion and their decomposition near the surface of the ion exchanger grains. The proposed hypothesis is confirmed by quantitative studies and comparison with available experimental data.
Show AbstractHeavy-ion Physics Results by the Compact Muon Solenoid (CMS) Expe\-riment at the Large Hadron Collider (LHC)
Heavy-ion Physics Results by the Compact Muon Solenoid (CMS) Expe\-riment at the Large Hadron Collider (LHC)
S. V. Petrushanko
This publication presents the latest experimental results on the physics of relativistic heavy ion collisions obtained at the Compact Muon Solenoid (CMS) facility at the Large Hadron Collider (LHC) at CERN.
Show AbstractTHE CONDITIONS FOR THE FORMATION OF 17 SUPERCONDUCTING PAIR CORRELATIONS IN SPHERICAL EVEN-EVEN NUCLEI
THE CONDITIONS FOR THE FORMATION OF 17 SUPERCONDUCTING PAIR CORRELATIONS IN SPHERICAL EVEN-EVEN NUCLEI
V. A. Kuz'min$^1$, T. V. Tetereva$^2$
The formation of superconducting pair correlations between like nucleons in the ground state of spherical even-even nuclei is considered within a special Bogoli ubov transformation. The inuence of the monopole pairing interaction on the energy of single-particle states is taken into account. It is shown that the appear ance of pair correlations depends on the particle number and shell structure. In open subshell nuclei the correlations exist at any attractive monopole interaction and nucleon pairs are distributed over all subshells participating in the pairing interaction. It is con rmed that the superconducting pair correlations appear if the coupling constant exceeds a certain threshold value. Rough upper and lower estimates are obtained for the threshold value
Show AbstractMisalignment alignment influence on MPD TPC track reconstruction
Misalignment alignment influence on MPD TPC track reconstruction
V. A. Kuzmin
Using the previously developed method for finding the alignment of the Time Projection Camera (TPC) in the MPD detector, we study the effect of misalignment on the reconstructed parameters of a charged particle track, such as transverse momentum and velocity. The concept of a misalignment unit is introduced for TPC. By simulating the reaction of the TPC to charged particles, we study the distortions that are introduced into the reconstructed track parameters depending on the magnitude of the misalign- ment. The effect of misalignment on the reconstructed track parameters in the MPD TPC is negligible. There is a systematic shift in the measured transverse momentum, depending on the track projection width. This width is determined by the gas and electrical field conditions within the detector chamber. Alignment tools developed for the MPD Time Projection Chamber allow us to estimate this width using experimental data and apply corrections to the reconstructed track parameters.
Show AbstractAn algorithm for study transiting exoplanet candidates by the MASTER global robotic telescope net
An algorithm for study transiting exoplanet candidates by the MASTER global robotic telescope net
A. N. Tarasenkov$^{1,3}$, V. M. Lipunov$^{1,2}$, A. S. Kuznetsov$^1$, N. M. Budnev$^4$, A. G. Tlatov$^5$, V. V. Yurkov$^6$
The paper presents the basic principles of photometric research of exoplanet candidates through the analysis of archival wide-field images obtained on robotic telescopes of the MASTER global network of Moscow State University. An algorithm for studying candidates for transiting exoplanets was proposed and applied to study and search for candidates for transiting exoplanets. It which does not interfere with the performance of the main tasks of the MASTER network - detection of optical components of high-energy astrophysical sources and study of the processes occurring in them on various time scales. A number of candidates from the field of microquasar V404 Cyg were studied. For the candidate TOI-3570.01, a light curve was obtained during the transit of a putative exoplanet with a high photometric accuracy.
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