Analytical models of the nonstationary planet’s physical fields in the local version
Analytical models of the nonstationary planet’s physical fields in the local version
I. E. Stepanova$^1$, I. I. Kolotov$^2$, A. V. Shchepetilov$^2$, A. N. Levashov$^2$
The local and regional versions of the linear integral representation method proposed is implemented for the interpretation of anomalous time-dependent field data. The reconstruction of the field elements is reduced to solving linear algebraic equation system with the approximately given right-hand side. The results of the non-stationary gravity c field modeling are given.
Show AbstractImpact of oxygen atoms insertion into the molecular structure of organic semiconductor Ph-BTBT-C10 on its electronic and optical properties
Impact of oxygen atoms insertion into the molecular structure of organic semiconductor Ph-BTBT-C10 on its electronic and optical properties
A. Yu. Sosorev$^1$, S. N. Korchkova$^2$
For efficient practical application of organic field-effect transistors, the organic semiconductors constituting their active layers should combine high charge mobility with decent operational stability; light-emitting transistors should also show efficient luminescence. In this study, we suggest three novel derivatives of the popular organic semiconductor Ph-BTBT-C10 with oxygen atoms inserted into decyl substituent and/or as a part of methoxy group at phenyl ring, and investigate the suggested compounds using DFT calculations. It is shown that such a modification of chemical structure affects the torsional angle between the phenyl ring and the BTBT core, rises the energy levels of frontier molecular orbitals, lowers the S0-S1 transition energy and enhances the corresponding oscillator strength, increases the static dipole moment and makes the electrostatic potential more inhomogeneous. The molecules suggested are expected to show more efficient luminescence and stronger intermolecular interactions, which should positively affect the stability of oranic (opto)electronic devices. We anticipate that the revealed structure-property relationships for the organic semiconductors investigated will facilitate the rational design of these materials.
Show AbstractNear-infrared autofluorescence of human skin: marker of metabolic processes and the mechanism of formation
Near-infrared autofluorescence of human skin: marker of metabolic processes and the mechanism of formation
B. P. Yakimov, A. A. Rubekina
Near-infrared autofluorescence (NIRAF) of biological tissues is traditionally regarded as a background signal in Raman spectroscopy; however, its diagnostic potential and molecular origins remain poorly understood. This study presents a quantitative analysis of an open-access dataset of Raman and NIRAF spectra from human skin measured \textit{in vivo} with 785 nm excitation. We show that NIRAF intensity is statistically significantly higher in patients with type 2 diabetes than in healthy volunteers and correlates with glucose and glycated hemoglobin levels. No dependence on age, body mass index, or gender is observed. Using model systems, we demonstrate that protein oxidation and glycation products, which exhibit broad absorption and fluorescence spectra, may contribute to skin NIRAF. These findings indicate the potential of NIRAF as a noninvasive marker of metabolic disorders associated with oxidative stress and hyperglycemia.
Show AbstractThree-dimensional distribution of electron concentration in the volume of a wall-unbounded hollow cathode discharge
Three-dimensional distribution of electron concentration in the volume of a wall-unbounded hollow cathode discharge
A. V. Bernatskiy$^1$, I. I. Draganov$^{1,2}$, V. V. Lagunov$^1$, A. J. Sadurni Sorokin$^{1,3}$, V. N. Ochkin$^1$
In a discharge with a rectangular hollow cathode and a mesh anode, three-dimensional spatial measurements of the electron concentration were performed. The measurement region significantly exceeded the discharge aperture, including the space behind the anode. It was found that a considerable electron concentration is observed in the region behind the anode. The effect of electrons bypassing the anode is observed along its entire surface.
Show AbstractMethod of controlled local laser oxidation of porous silicon photonic crystals
Method of controlled local laser oxidation of porous silicon photonic crystals
L. G. Kuznetsov, N. I. Pyshkov, S. E. Svyakhovskiy
A method of controlled local laser oxidation of porous silicon-based photonic crystals is presented. The process of thermal oxidation of photonic crystals by pulsed and continuous laser radiation is experimentally studied. The dependence of the spectral shift of the photonic band gap on the laser radiation power and processing time is investigated. The possibility of local oxidation according to a given pattern is demonstrated.
Show AbstractMatrix elements of pair projectors for a three-body system in a Gaussian basis
Matrix elements of pair projectors for a three-body system in a Gaussian basis
V. T. Voronchev, V. N. Pomerantsev
Analytical formulas are found for matrix elements of operators like pair projectors (e.g., Pauli projectors) for a three-bode system when using a multidimensional Gaussian basis, including symmetrized one. Expressions for the overlap of three-bode basis functions and a given function of particle pair are presented. A method for projecting two-body central potentials in a threebody system on a certain orbital state is also considered. The results can be used in variational calculations of three-body systems in nuclear, atomic, and molecular physics.
Show AbstractSelf-assembly in polymer brushes composed of amphiphilic comb-like copolymers: phase diagram
Self-assembly in polymer brushes composed of amphiphilic comb-like copolymers: phase diagram
E. M. Zarkova$^{1,2}$, D. E. Larin$^2$
Polymer brushes are a class of modifiers that enable control over surface properties depending on the chemical composition of the grafted macromolecules and external conditions. This paper examines planar polymer brushes consisting of amphiphilic comb-like copolymers, which comprise a hydrophobic backbone, to each monomer unit of which hydrophobic groups are attached, and regularly distributed hydrophilic (polar) side groups, in the case of their very dense grafting onto an impermeable inert surface. Within the framework of mean-field theory, a theoretical model of self-assembly in an amphiphilic polymer brush was developed. Phase diagrams were constructed for variations in the copolymer’s molecular parameters and grafting density. The diagrams include regions of existence of cylindrical aggregates, lamellae, a porous layer, and a homogeneous brush. It was found that in the region of high solubility of polar groups, a re-entrant transition «homogeneous brush → cylindrical aggregates → homogeneous brush» occurs as the grafting density increases. The obtained results are compared with data from the literature.
Show AbstractFaraday effect of ferromagnetic metal films in the terahertz region of the spectrum
Faraday effect of ferromagnetic metal films in the terahertz region of the spectrum
M. A. Simdyanova, A. B. Granovsky
Within the framework of Maxwell's equations and the Boltzmann kinetic equation, expressions for the Faraday rotation of ferromagnetic metal films in the terahertz region of the spectrum are obtained. It is shown that, with the dominant mechanism of asymmetric scattering of the anomalous Hall effect, the Faraday rotation has a square root frequency dependence and can reach values of 102 rad/cm. A comparison of magneto-optical effects in the terahertz region of the spectrum on reflection and transmission is presented.
Show AbstractHigh-precision semi-analytical method for solving the problem of electromagnetic wave scattering by an ensemble of parallel circular cylinders
High-precision semi-analytical method for solving the problem of electromagnetic wave scattering by an ensemble of parallel circular cylinders
V. V. Ternovski$^2$, M. I. Tribelsky$^1$
A method for solving the two-dimensional problem of electromagnetic radiation scattering by a cluster of an arbitrary number of parallel, infinite, homogeneous, straight, circular, non-intersecting cylinders is proposed. Each cylinder can have arbitrary values of radius and complex permittivity, and their axes, while remaining parallel, can occupy an arbitrary position in space. The solution is based on an analytical expansion of the electromagnetic field in cylindrical harmonics. Multiple scattering is taken into account using Graf's addition theorem, which leads to a linear system of equations for the expansion coefficients. This system is solved numerically with conditionality control and, if necessary, in high-precision arithmetic, followed by multi-stage convergence verification. The method enables obtaining numerically verified solutions with controlled accuracy over a wide range of parameters, including densely packed subwavelength configurations. As an example, the scattering of a plane, linearly polarized, monochromatic wave by a subwavelength cluster of three identical aluminum nanocylinders is studied. The scattering, absorption, and extinction cross sections, as well as the scattering indicatrix, were calculated and analyzed. Field lines of the Poynting vector were constructed. They demonstrate the redistribution of energy flow between the cluster cylinders and the formation of localized regions of field enhancement near their surfaces.
Show AbstractInteraction of the massless scalar field with Three-dimensional delta-potential
Interaction of the massless scalar field with Three-dimensional delta-potential
P. A. Spirin
We consider problems related with appearance and usage of the three-dimensional zero-range potential which interacts with the massless scalar field: namely, the construction of exact Hadamard functions and a problem of vacuum polarization. The solution to these problems implies the renormalization of bare delta-potential's coupling $\lambda$ into the finite $\lambda_{\ren}$. The renormalized Hadamard functions of the massless real-valued scalar field ~$\phi$ are presented in a form of single-variable integral. The latter is Riemannian as $\lambda_{\ren}<0$ and the Cauchy-integral as $\lambda_{\ren}>0$. With help of The renormalized Hadamard function the vaccum-average $\langle \phi^2\rangle$ is computed in a form of the integral exponential.
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