195251, St. Petersburg,
Politekhnicheskaya, 29, Building No.1, room 130 
+7 (812) 294-2285 (10 - 18)
physics@spbstu.ru

Gorobei Natalia N., Luk'yanenko Alexander S.

On the energy balance in the thermoelastic effect

Published in category «Condensed matter physics»

The energy balance in the thermoelastic effect is analysed in the framework of the mechanically deformed ensemble of anharmonic oscillators. As the result, two aspects of mechanical loading - the macroscopic deformation of a sample, with corresponding addition to the energy balance (the mechanical work), and the vibration energy of oscillators change at the microscopic level, are separated. Between these two parts of the internal energy of the sample the exchange in the thermo-elastic effect takes place. The low temperature limit in which the vibration energy reduces to the energy of zero vibrations is also considered.

Views: 1458 Comments: 0

Arefyev Konstantin M., Hrushchenko Alexander A.

The calculation of oxygen mass exchange in human lungs

Published in category «Simulation of physical processes»

The article considers the impact of the diffusion capacity of the lungs to process oxygen transfer from the gas phase of the alveoli into the blood capillaries of the lungs. The main transport of oxygen in the blood takes place in a bound state with the hemoglobin of red blood cells. Therefore, the diffusion capacity of the lungs to transport gases other than diffusion through tissue affects the rate of reaction of oxygen with hemoglobin and red blood cell membrane permeability. The dependence of the reaction rate of oxygen on hemoglobin oxygen tension is analyzed using various literary sources. Using a mathematical model of the lungs and experimental data taken from the literature the rate of oxygen reaction with hemoglobin was evaluated. Numerical results when compared with the experimental data showed a good result.

Views: 1449 Comments: 0

Lebedeva Olga S., Lebedev Nikolai G.

The influence of the stretching and compression deformations on the piezoresistance of the carbon nanotubes and graphene nanoribbons

Published in category «Atom physics and physics of clusters and nanostructures»

In this article the influence of the stretching and compression on the conducting properties of carbon nanoparticles (nanotubes, nanoribbons) accounting the changes in the transverse dimensions of the sample is studied theoretically. The analytical calculation of piezoresistive constants of carbon nanoparticles with the account of transverse strain was carried out. It is shown that the elastoconductivity tensor of metallic nanotubes is independent of its diameter. The monotonic increase in the longitudinal component of the tensor with the increasing its diameters of semiconducting nanotubes was obtained. It is shown that increasing or decreasing of the piezoresistive constant of semiconducting nanotubes with the relative tension or compression strain.The results are compared with the literature data. A physical justification of the observed dependence was described.nanoparticles (nanotubes, nanoribbons) accounting the changes in the transverse dimensions of the sample is studied theoretically. The analytical calculation of piezoresistive constants of carbon nanoparticles with the account of transverse strain was carried out. It is shown that the elastoconductivity tensor of metallic nanotubes is independent of its diameter. The monotonic increase in the longitudinal component of the tensor with the increasing its diameters of semiconducting nanotubes was obtained. It is shown that increasing or decreasing of the piezoresistive constant of semiconducting nanotubes with the relative tension or compression strain.The results are compared with the literature data. A physical justification of the observed dependence was described.

Views: 1119 Comments: 0

Kanunnikova Elena A.

Analytic-numerical method to solve 3D exterior boundary problems for elliptic equations

Published in category «Mathematical physics»

The paper considers analytic-numerical method to solve 3D exterior problems for elliptic equations under Dirichlet and Neumann boundary conditions in half-space. The solution algorithm is concerned

Views: 1251 Comments: 0

Pakhotin Vladimir A., Zakrevskii Vladimir A., Kharaldin Ivan A.

Some features of measurement of breakdown current through dielectrics

Published in category «Experimental technique and devices»

Some different circuits for measurement of breakdown current through dielectric films have been analyzed and a notion for shunting discharge current in a capacitor measuring cell flowing along the breakdown canal was introduced. A circuitry for measurement of breakdown current was put forward. It permits one to work out the shunting current and the breakdown canal resistance using the results of measurements of pulse parameters of breakdown current.

Views: 1247 Comments: 0

Golovkov Oleg L., Stepanov Vladimir A., Kuptsova Galina A.

Influence of the extent of uniform broadening of an amplification line on the generation spectrum of YAG : Nd laser

Published in category «Experimental technique and devices»

The theoretical investigation given in the paper is directed towards the elucidation of the influence ofthe extent of uniform broadening of an amplification line on the generation spectrum of YAG : Nd laseroperating in the modes of the one-wavelength (1064,2 nm) and two-wavelength (1064,2 nm and 1061,5 nm)generations. The results obtained are compared with another ones presented in published literature.

Views: 1296 Comments: 0

Golovkov Oleg L., Stepanov Vladimir A., Kuptsova Galina A.

The rate consideration of relaxation transitions between sublevels of a multiplet in the generation spectrum of YAG:Nd-laser

Published in category «Experimental technique and devices»

The two alternative forms of the Tang - Statz - DeMars system of equations are presented in the paper. The spectra of the multimode generation of YAG: Nd +3-laser are calculated assuming the Boltzmann distribution over the sublevels of the 4F3/2 multiplet and a specific rate of cross-relaxation transitions between those sublevels. The results obtained are compared with experimental data.

Views: 1195 Comments: 0

Petrov Victor M., Khomenko Anatoly V., Krinitsky Yakov A., Garcia Sarate Maria Alejandro

Light pressure detection by two-wave mixing in the photorefractive BaTiO3:Co crystal

Published in category «Experimental technique and devices»

The paper studies the high-sensitive detection of light radiation pressure using an adaptive interferometer based on photorefractive 45○-cut BaTiO3 : Co crystal. For small phase modulation measurement the authors employed a polarization filtering, which ensured the linear regime of signal detection in the photorefractive crystal with nonlocal response. It was demonstrated that the proposed method of light pressure measurement could be used as a broadband photodetector. It was experimentally found that the sensitivity was 2 µW in the wavelength range from 488 to 1600 nm.

Views: 1404 Comments: 0

Andronov Alexander N.

Secondary electron emission at very low electron energy

Published in category «Physical optics»

A detailed review of experimental and theoretical studies of secondary electronemission (SEE) at low electron energies performed in the past has been given in this paper. It is shown that some present-day authors’ statement on increase of the SEE yield up to unity while the primary electron energy tends to zero does not have sufficient theoretical justification and is inconsistent with the numerous experimental data obtained for various materials.

Views: 1244 Comments: 0

Popugaeva Еlena А., Vlasova Olga L., Bezprozvanny Ilya B.

The role of intracellular calcium in the development of Alzheimer disease pathogenesis

Published in category «Biophysics and medical physics»

This article is a review and contains a brief description of the current state of research in the field of AD. The special attention is paid to the calcium hypothesis of AD, which is getting more popular and is an alternative hypothesis in relation to the dominant amyloid hypothesis of AD. The assumption of possible pathological pathway that takes place in AD is made basing on published and preliminary data.

Views: 1352 Comments: 0

Vlasova Olga L., Plotnikova Polina V., Bezrukova Alexandra G.

Algorithm of realization of the experimental optical parametric methods for biological disperse systems analysis

Published in category «Biophysics and medical physics»

The article is devoted to the development and practical testing of the experimental and parametric optical methods for determining and comparing of liquid biological disperse systems on the basis of multiparametric optical analysis.

Views: 1195 Comments: 0

Sabantsev Anton V., Fedechkin Stanislav O., Khodorkovskii Mikhail A., Pobegalov Georgiy E., Vedyaykin Alexey D., Smirnov Sergey L.

Characterisation of villin domain 6 calcium-binding properties

Published in category «Biophysics and medical physics»

Using intrinsic protein fluorescence spectroscopy actin-regulating protein villin domain 6 calcium-binding properties were characterized. Acquired data suggests the presence of calcium-binding site in villindomain 6. The affinity of this calcium-binding site was estimated to be 32 µM, which suggested that the domain could be responsible for physiological transition of villin from bundling to severing actin filaments in response to the increase of intercellular calcium concentration.

Views: 1639 Comments: 0

Ivanishchev Dmitry A., Ivanov Alexey E., Kotov Dmitry O.

K* and ω-mesons production in d + Au collisions at 200 GeV

Published in category «Nuclear physics»

Invariant transverse momentum spectra obtained for K*- and ω- mesons in d + Au collisions at 200 GeV have been presented. Comparison of the obtained results with existing measurements for π0-, Ks-, η-, η'- and φ-mesons have been made. The systematic study for light mesons production in central d + Au collisions have been carried out.

Views: 1305 Comments: 0

Petrichenko Mikhail R., Serov Dmitry V.

Complete and incomplete additive doubling variables in linear systems with constant coefficients

Published in category «Mathematics»

Differential equations and their systems, not associated with any of the variational problems have been put forward to transform up to Hamiltonian form and immerse their solutions into a bundle of extremities. For small momenta the doubled system of the equations corresponds closely with the original one but for the equations in variations.

Totally or partly additive doubled system of linear equations with constant coefficients has a Hamilton structure. For Jordan cells in the matrix of coefficients of the system complete and partial doubling correspond closely, with an accuracy up to a shift operator, which is representable in the basis of its own and associated vectors of a nilpotent matrix.

Views: 1400 Comments: 0

Kondrashkov Anatoly V., Pichugin Yuri A.

On the identification and statistical testing stability of the Volterra model

Published in category «Mathematics»

Some aspects of the Volterra model are considered in the paper. The emphasis is both on the determination of solution stability area in the space of model parameters and on statistical testing of stability.

Views: 1137 Comments: 0

Rykshin Alexei Yu., Zatsepin Pavel M., Ulanov Petr N.

The modeling of a short electromagnetic pulse scattering by dual layers structure using wavelet transform

Published in category «Radiophysics»

In the paper the problem of a short electromagnetic pulse scattering by dual dielectric layers structure has been considered. An incident field was generated by infinitely thread-like source of electric or magnetic current located parallel to the boundaries of layers. The solution was written through the Fourier transform with respect to the spatial coordinates and wavelet transform with respect to the time coordinate. Electromagnetic fields characteristics within the given structure and in the surrounding space were studied.

Views: 1263 Comments: 0

Golubev Anatoliy G., Smirnov Aleksey S.

The calculation of a tolerable noise level for the receiving sectionin the underwater acoustic unit containing an antenna with fibre-optic hydrophones

Published in category «Radiophysics»

The dynamic range of the section for signals pre-processing in the underwater acoustic unit is conditioned by hydrophones sensitivity of the receiving antenna and by the internal noise level of operative assemblies composing the section. When we use a receiving antenna with interferometric fiber-optic hydrophones in that complement, optical and digital components are parts of the section. Our paper focuses on the calculation technique to get tolerable internal noise level reduced to the hydrophone input value. The technique is concerned with the underwater-acoustic unit containing receiving antenna with interferometric fiber-optic hydrophones.

Views: 1179 Comments: 0

Golubev Anatoliy G., Molchanov Pavel A.

Estimation algorithms for impulse response of multibeam communication channel with transformation of the working frequency band

Published in category «Radiophysics»

In transmission messages, the prediction about the form of every information signal, as a rule, is carried out using response of communication channel on test impulses. To avoid errors in predictions of intersymbol interference it is useful to apply the jump of carrier frequencies from one test impulse to another one. In this case it is necessary to make an estimate of channel impulse response in frequency band of information signals from channel response on series of test impulses, which transmitted in different frequency bands. Our article focuses on the algorithms for this estimation.

Views: 1163 Comments: 0

Vasil'eva Maria A., Gavricova Tatiyana A., Zykov Valery A., Ilyin Vladimir I., Shalygin Vadim A.

Actual directions of semiconductor physics and nanostructures, semiconductor nano- and optoelectronics (on the 15th All-Russian Youth Conference)

Published in category «Chronicle»

Short review of results of the conference is done. The works, recommended to practical using, are mentioned.

Views: 1335 Comments: 0

Morachevski Andrey G., Firsova Elena G.

Professor Vladimir Efimovich Grum-Grzhimailo (on the occasionof his 150th birthday)

Published in category «Chronicle»

The article is dedicated to the life and creative work of V.E. Grum-Grzhimailo (1864 - 1928), who was an outstanding Russian and Soviet inventor, a metallurgical engineer, a pedagogue and a production organizer. He also was a corresponding member of the Academy of Science of the USSR (elected in 1927). For 11 years he was a lecturer at St. Petersburg Polytechnical Institute.

Views: 1301 Comments: 0