Optical methods for determining the relationship between the biophysical constant of osmolarity and the parameters of aqueous biological solutions.
Optical methods for determining the relationship between the biophysical constant of osmolarity and the parameters of aqueous biological solutions.
J. A. Guseva$^1$, V. V. Davydov$^2$, D. S. Provodin$^3$, D. V. Davydova$^4$
The early diagnosis of chronic kidney disease is critically important due to the asymptomatic progression of the condition in its initial stages and its increasing prevalence. This study substantiates the need to develop novel, accessible, and non-invasive diagnostic approaches based on optical technologies. A method based on refractometric measurement of urine refractive index is proposed, enabling the quantitative evaluation of key physicochemical parameters. Reliable linear relationships between urine osmolality, density, and temperature were established. The method demonstrates high measurement accuracy (±0.0001) and stability over a wide temperature range (288–303 K), making it a competitive and cost-effective alternative to traditional diagnostic techniques such as urinalysis strips, urinometry, and osmometry. Regression equations were developed to estimate osmolality based on density ($\mathrm{Os} = 33.128\rho - 33.107$) and density based on refractive index ($\rho = 2.4322n - 2.2444$). The results confirm the feasibility of using refractometry as a tool for rapid, non-invasive assessment of kidney function and early detection of CKD. The proposed approach simplifies routine clinical analysis and has the potential for implementation in both laboratory and point-of-care settings.
Show AbstractStructural relaxation of coloration centers in amorphous silicon dioxide
Structural relaxation of coloration centers in amorphous silicon dioxide
L. V. Nikiforov$^1$, D. S. Dmitriyeva$^1$, D. S. Provodin$^2$, V. V. Davydov$^{2,3}$
The use of electronic and optical devices under conditions of increased ionization irradiation requires the study of defects arising in the materials from which the devices are composed. One of the most common components of such devices is silicon dioxide (SiO2), both in crystalline and amorphous form. The most common defect induced by high-power ionization radiation is the E' center. In this work, one of the existing models of the E' center structure is investigated using electron paramagnetic resonance (EPR) on different samples of amorphous silicon dioxide. The results obtained indicate the presence of two stable states of defects at high and low doses of ionization irradiation. Experimental results do not fully explain the theoretical calculations given by scientists earlier, but based on them we can assume the features of the defect structure and form a direction for further research, as well as possible options for making changes in the production technology of optical fiber to weaken the influence of this defect.
Show AbstractNoether’s theorem and quantum mechanics
Noether’s theorem and quantum mechanics
A. V. Borisov
In this methological paper, we show that, by considering the Schr¨odinger and Pauli equations for the wave function of a particle as the Lagrange equations of classical field theory, it is possible, on the basis of Noether’s theorem, to obtain Noether charges (constants of motion) in the form of quantum-mechanical expectation values of the observables of thep article, to which are associated self-adjoint operators of energy, momentum and angular momentum, as well as the law of conservation of probability.
Show AbstractNumerical simulation of spatial configurations of a series of amino acids by solving the Schrödinger equation
Numerical simulation of spatial configurations of a series of amino acids by solving the Schrödinger equation
I. A. Shatskov
The numerical method of K. E. Plokhotnikov for solving the Schrödinger equation is applied to spatial configurations of eleven proteinogenic amino acids (glycine, alanine, valine, leucine, isoleucine, proline, serine, threonine, cysteine, tyrosine, tryptophan) in their canonical PubChem geometries. The method combines stochastic Monte-Carlo discretization of configuration space with a finite-difference approximation of the kinetic energy operator. A scheme of valence-electron positioning with delocalization along covalent bonds and with the number of valence electrons fixed by the group number of the periodic table is employed. For all 11 structures, the relative deviation of the discrete-Hamiltonian eigenvalue Ω_I from the reference total-energy estimate E_ref is below 0.02 %, and Ω_I lies in the middle part of the spectrum in all cases. Tryptophan is examined as the most complex example (135 quantum particles; configuration-space dimension 405).
Show AbstractAnalysis of Pulsating Gas-Dynamic Flows Using Proper Orthogonal Decomposition
Analysis of Pulsating Gas-Dynamic Flows Using Proper Orthogonal Decomposition
V. D. Petri$^1$, I. E. Ivanov$^1$, I. A. Kryukov$^2$
This work is devoted to the development of algorithmic tools for extracting stable structures (modes, coherent structures) associated with oscillations in unsteady gas-dynamic fields. The research area related to modal decomposition is actively developing, since it has a number of advantages over traditional methods for processing data obtained from numerical or physical experiments. This work uses one of the well-established methods of modal analysis, namely Proper Orthogonal Decomposition (POD). The method consists in representing the pulsating part of a field as a sum of products of temporal and spatial modes (basis functions), each of which approximates the field in the sense of the best quadratic approximation; this makes it possible to interpret such modes as the most significant flow structures within the chosen measure. Finding the basis functions on a grid is based on methods of linear algebra and is reduced to finding the right and left singular vectors of the singular value decomposition (SVD) of a matrix containing field distributions at fixed time instants. The algorithm was tested on a model problem. Numerical studies were then carried out for two-dimensional flows arising when a gas medium flows around bodies of different shapes (a square cylinder and a NACA 0012 airfoil), in regimes where a von Karman vortex street is formed.
Show AbstractModel of the control and management system for a linear electron accelerator based on EPICS
Model of the control and management system for a linear electron accelerator based on EPICS
M. Yu. Kopatch$^{1,3}$, A. N. Ermakov$^{2,3}$
A linear electron accelerator was physically launched at the Skobeltsyn Institute of Nuclear Physics with the assistance of the MSU Laboratory of Electron Accelerators to solve problems of fundamental and applied research. This work is devoted to the initial stage of the development of an accelerator control and monitoring system based on the EPICS software package. The created model of the monitoring and control system consists of several controllers used in industrial accelerators, as well as third-party controllers. Within the framework of the model, information is collected and transmitted between controllers and a control computer, and control logic based on virtual finite state machines is implemented.An algorithm has been developed to include new controllers based on the Modbus data transmission protocol in the system for flexible modernization of the future control system.
Show AbstractHyperon appearance in neutron star matter within Skyrme approach and relativistic mean field theory
Hyperon appearance in neutron star matter within Skyrme approach and relativistic mean field theory
S. A. Mikheev$^{1,2}$, D. E. Lanskoy$^1$, A. I. Nasakin$^{1,2}$, T. Yu. Tretyakova$^{1,2}$
Density at which the appearance of hyperons becomes energetically favorable is an important property of neutron star matter. Within two theoretical approaches, namely the nonrelativistic Skyrme model and relativistic mean field theory, we study how this characteristic depends on the properties of the hyperon–nucleon interaction. We show that the density of hyperon appearance strongly correlates with the contracting power of the hyperon–nucleon interaction, a quantity that characterizes the ability of a hyperon to polarize (compress or expand) the nucleonic core of a hypernucleus.
Show AbstractDependence of photoelectron angular distributions on the magnitude of hyperfine interaction in hydrogen-like targets in a pump-probe scheme
Dependence of photoelectron angular distributions on the magnitude of hyperfine interaction in hydrogen-like targets in a pump-probe scheme
K. A. Gnedovskaya$^1$, M. M. Popova$^2$, A. N. Grum-Grzhimailo$^2$, E. V. Gryzlova$^2$
In the paper, we examine the ionization of a hydrogen-like target in a pump-probe scheme. We analyze the polarization of the target during pumping its levels with total angular momentum of the electron shell 1/2 and 3/2 by a linearly or circularly polarized field. We examine the extent to which the polarization of the prepared (pumped) state can degrade due to hyperfine interactions. Depolarization itself is a phenomenon that manifests itself in a wide variety of processes. This work examines the manifestation of depolarization in the angular distributions of photoelectrons during subsequent ionization by a field also polarized linearly or circularly (with helicity equal or opposite to the pump field).
Show AbstractEstimation of the charging efficiency of micron-sized aluminum particles in an electrostatic injector
Estimation of the charging efficiency of micron-sized aluminum particles in an electrostatic injector
S. S. Avtorin$^{1,2}$, S. A. Bednyakov$^1$, O. M. Marchenko$^1$, N. B. Akimov$^1$, O. B. Dzagurov$^1$, O. P. Glotov$^1$, C. N. Gavrilovich$^{1,2}$
The correct assessment of the risks of reducing or losing the functionality of the open surfaces and instruments of the spacecraft is based, inter alia, on laboratory tests of the resistance of the relevant materials to the impact of particles simulating the flow of solid particles in laboratory conditions. In this work, the charge spectrum of PAP-1 aluminum dust particles was obtained using a stand consisting of an electrostatic injector, a parameter control unit, and a research chamber. The experimental spectrum was also correlated with the theoretical one. The distributions of such physical parameters of particles as size, velocity, and mass are obtained.
Show AbstractCharged-particle pseudorapidity and centrality distributions in Pb--Pb collisions at 5.36 TeV in the HYDJET++ model and comparison with LHC data
Charged-particle pseudorapidity and centrality distributions in Pb--Pb collisions at 5.36 TeV in the HYDJET++ model and comparison with LHC data
V. S. Bratyshev$^1$, D. A. Myagkov$^{1,2}$, S. V. Petrushanko$^{2,3}$
This work presents a comparison of the CMS experimental data on charged-particle pseudorapidity and centrality distributions in Pb--Pb collisions at record energy 5.36 TeV at the LHC with the results obtained from the HYDJET++ Monte Carlo generator using simulation with its default settings.
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