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


Физика

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.

Range of Gamma Quanta in the Beryllium Target

Changes of an initial brake range of gamma quanta in a sample are analysed. It is shown that the main mechanism influencing g quanta range form in a sample of beryllium is Compton’s effect. In work this amendment is considered in the analysis of an exit of photoneutrons. However unlike the models considered in other works at the accounting of Compton dispersion parametrization isn’t used.

Power Range of Photoneutrons from 209Bi at Е γmax = 12 MeV

On a bunch of brake radiation of the betatron the power range of photoneutrons from 209Bi is measured. Measurements are executed by means of a scintillation spectrometer on the basis of a stilbene crystal with discrimination γ-radiations in an impulse form. The obtained data are compared with known of literature and analyzed on the basis of evaporation model.

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, counterpointed and concave-pointed) was studied for the current oscillations parameters (the threshold voltage, frequency and amplitude of current oscillations) reproducibility increasing.

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.

Chaos in the System of Three Coupled Rotators: from Anosov Dynamics to Hyperbolic Attractor

The work presents an example of a system with chaotic dynamics built of three rotators by modifying a conservative system with hyperbolic Anosov dynamics. Results of a computational study of chaotic dynamics are considered (portraits of attractors, time dependences of the variables, Lyapunov exponents, and spectra) and good correspondence is observed between the dynamics on the attractor of the proposed system with the reduced model, characterized by the Anosov dynamics at appropriately defined energy.

Nonequilibrium the Microwave Plasma of Low Pressure in Scientific Researches and Development Micro and Nanoelectronics

Advantages and benefits realization use of nanotechnology of high ionized low-energy microwave plasma of low pressure are described. It presents the fact that one installation on the basis of microwave plasma can replace up 4 to 5 installations with usual high-frequency excitation of the gas discharge.

Model of Cardiovascular System Autonomic Regulation with a Circuit of Baroreflectory Control of Mean Arterial Pressure in the Form of Delayed-Feedback Oscillator

A mathematical model of human cardiovascular system autonomic regulation is proposed having the form of differential equation set. Some equations of the model contain terms with time delay. The spectral analysis shows that the proposed model exhibits better qualitative and quantitative coincidence with experimental data than the known models.

Statistic Characteristics of Akulinichev’s Map

Perron – Frobenius equations for Akulinichev’s map are formulated. The autocorrelation function of the map orbits is analytically calculated. 

Digital Speckle Photography with Correlation Processing of Spatial Spectrum of Specklegram for Determination of Micro Displacement of Scattering Object

The method of digital speckle photography for determining of speckle pattern displacement with sub-pixel accuracy using correlation processing of summary spatial spectrum of speckle patterns is considered in this article. It is assumed that displacement of speckle pattern is caused by deformation or displacement of an object with a scattering surface. The method of phase shift of interference pattern in diffraction halo is proposed for expanding the lower limit of measuring range of speckle pattern displacement to subpixel values.

Pages