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].

Microwave Photonic Crystals. New Application Areas

The theoretical and experimental justifications of the possibility to use the microwave photonic crystals for the creation of broadband loads have been presented. The possibility to simultaneously determine the thickness and the conductivity of nanometer semiconductor layered structures by use of the microwave photonic crystals has been shown. The possibility of electrical control of the microwave photonic crystals amplitude-frequency characteristic has been experimentally demonstrated.

Research of the Contact Pads Topology Influence on the Parameters Reproducibility of the Current Oscillations in Mesa-Planar Structures Based on Semi-Insulatinggallium Arsenide

Experimental results of research the influence of the electric field distribution between the pads of mesa-planar resistor structures based on semi-insulating n-GaAs are represented. These influence by changing pads topology (plane-parallel, flat-pointed, counter-pointed and concave-pointed) was studied for the current oscillations parameters (the threshold voltage, frequency and amplitude of current oscillations) reproducibility increasing.

Creating and Fluorescence of the Multilayer Langmuir – Blodgett Films of CdSe/CdS/ZnS Quantum Dots

Multilayered structures composed by Langmuir – Blodgett films of CdSe/CdS/ZnS quantum dots functionalized by oleic acid and fluorescent at 525 and 631 nm were prepared and studied by fluorescent spectroscopy. It was shown that fluorescent spectra of the nanosized multilayered film consisting of different QD layers have complex character and can be rearranged with relative positions of QD layer and laser beam that open possibility to operate the fluorescent intensity of every QD layer.

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.

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 = σo2.

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.

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.

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