Izvestiya of Saratov University.
ISSN 1817-3020 (Print)
ISSN 2542-193X (Online)


Физика

Comparative Experimental Investigations of Backward Diffuse Light Scattering of Test Objects

The results of measurements of the spectral characteristics of the light scattering on test objects with different types of spectroscopic instruments were compared, backward diffuse scattering spectra, which were obtained with an integrating sphere and with the help of the illuminating and receiving optical fibers located at a short distance, were considered, the features of the spectral characteristics, which were determined by the parameters of the object, and the differences, which were caused by a method of recording of the spectrum, were identified in the scientifi

Kinetics of Diffusion-limited Elongation of DNA Fragments

The numerical model of the elongation kinetics of the single-stranded DNA has been proposed and studied. The proposed model is based on the principles of the phenomenological modelling and implemented as diffusion cellular automata. The analytical and numerical estimates of the elongation reaction rate for different concentrations of nucleotides has been obtained. The possibility of nucleotide binding delays with reducing the concentration of one of the nucleotides in the solution is shown. 

Study of Stochastic Andronov – Hopf Bifurcation in the Oscillator by a Numerical Method

We investigate soft Andronov – Hopf bifurcation in the Van der Pol self – sustained oscillator, which is under the influence of additive Gaussian white noise. To determine the bifurcation used numerical solution of the Fokker – Planck – Kolmogorov equation. The results are compared with the data of numerical integration of stochastic equations. Demonstrated the existence of a bifurcation interval calculated theoretically in [6].

Phase Dynamics Modeling Technique for Estimation of Delayed Couplings between Nonlinear Oscillators Accounting for Influence of Amplitudes

An established interval estimator of a time delay in coupling between oscillators, which is based on empirical modeling of phase dynamics and maximum likelihood formalism, is shown to give sometimes erroneous conclusions about the value of the time delay. It occurs when the dynamics of amplitudes affects phases, which is typical of nonlinear oscillatory systems under the influence of strong noises or in chaotic regimes. We suggest an empirical criterion to diagnose such situations and a modified estimator of time delay which allows one to avoid erroneous conclusions.

Surface Electromagnetic Waves in the of Optical Range (Surface Plasmon Polaritons – Spps): Their Properties and Applications

Surface plasmon polaritons (SPPs) are electromagnetic excitations, in wich electromagnetic field in dielectric is coupled to collective electron oscillation in metal, and propagate along and is tightly bound to metal/dielectric interfaces. First, we present an overview of SPPs in the optical range and their applications in optoelectronics and sensorics. We further present the main research results achived by the author in this area.

The Manifestation’s Research of the Pair Association in the Pyridine’s Ir-Spectrums by the Matrix Isolation Technique

The calculation of structure, frequencies of normal fluctuations and the strips intensity in IR-spectrums of five dimer of pyridine with hydrogen communication  has been performed by the matrix solation technique B3LYP/6-311+G (d, p). The number’s modeling of the difficult oscillatory contours in the pyridine’s IR-spectrum was executed taking into account the intermolecular interaction.

The influence of Morphology, Conditions of Production and External Effects on Nanoparticles’ (in Terms of Iron) Dielectric Properties

It was shown that the complex research of iron nanoparticles properties by different methods, supplemented each other, permit to receive the data about the interior sizes of nanoparticles, a number of physical properties of particles, their dependence on frequency and changes produced by various influences. It was found that the conductivity of nanoparticles changed under the square dependence σ = σo*ω2.

Microwave Absorption Spectra and Resonance Frequencies of a «Magnetic Nanocomposite Coating – Microstrip Line» Structure

This paper aims to look into microwave absorption spectra of «mag-netic nanocomposite coating – microstrip line» structure, containing magnetite Fe3O4 nanoparticles. The resulted spectra allowed to define the specific resonance frequencies of the structure under investiga-tion and to figure out the material parameters of the nanocomposite coating, that are, an effective magnetization, a volume fraction of magnetic nanoparticles in the coating as well as a magnetic crystal-line anisotropy filed.

Fluorescent Properties of Quantum Dots During Silanization Process

Quantum dots (QDs) are fluorescent semiconductor nanoparticles with unique optical properties. For bioapplication QDs have to be water-soluble. Here we describe one of common hydrophilization approaches – ligand exchange on silica precursors molecules and investigate fluorescent properties during this process.

Тhе Quasipotential Approach to the Syperfine Splitting of Muonic Hydrogen and Positronium

For the description of the two-partial atoms spectrum in quasipotential approach the relativistic amplitude is used. The interrelation of scattering amplitude expressions, corresponding to quantovoelektrodinamic corrections in various orders is traced. Arising from the accounting of delay effect the additional logarithmic corrections of the sixth order to the constant of fine structure in the bound level superfine shift are analyzed.

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