Electrospray ion source, which allows working with chromatographic sample solution flows under normal conditions, was tested. Dynamic division of the flow with diverting of the excess of non-sprayed solution is used in the field of electrospray.

Institute for Analytical Instrumentation of RAS, Saint-Petersburg

The paper presents two possible designs of dust impact mass spectrometer designed to meet the requirements of target size increasing with maintaining the design characteristics at the required level. The problems of modeling the device through the use of numerical electrostatic field in the path of the mass spectrometer calculation, as well as calculations of the trajectories of charged particles are described. For each of the structures the results of modeling the dependency characteristics of the device, such as resolution and collection rate, the place of collision of particles and the target are shown. As results of this modeling the optimal size of the spherical corrector and detector aperture are derived. The description of the experimental stand for dust impact mass spectrometers testing, as well as verifying characteristics obtained from simulation are given.

Samara State Aerospace University named after
academician S.P. Korolyov (National Research University), Samara

In this work a new type of monochromator for ion sources producing the ion flux with a wide energy range distribution is proposed. The method is based on converting the ion energy spectrum by the electric field pulses shocks on ions in the nonuniform electric field. This is followed by ion beam formation in the electrostatic field of the accelerating immersion lens. The monochromator pattern operation simulated mathematically shows its realizability as a compact and effective device for solving monochromatization problems in mass spectrometry.

Institute for Analytical Instrumentation of RAS, Saint-Petersburg

Ion transmission levels through a small quadrupole mass-analyzer with prefilters depending on the mass of the developed ion were determined experimentally. The results of mass spectrum records of perfluorotrinutylamine within the mass number of 69–502 u at R_0.1 = M in conditions of the mass-analyzer in question showed that transmission is in within 10–20 % from 100 % of the transmission, and on mass 69 u transmission level makes ~ 20 %, and on mass 502 u ~ 10 %. Dependence of transmission on ion mass for all the specified intervals of mass numbers at R_0.1 = M was obtained.

Institute for Analytical Instrumentation of RAS, Saint-Petersburg

We propose a method of estimating the position and the intensity of the peak in the doublet, mostly hidden peak, whose intensity is greater than the required 10 or more times in the presence of noise. The position of the main peak at exactly this set, its shape is known with some accuracy, but the amplitude is unknown. The method allows to estimate the parameters of the hidden peak at a signal / noise ratio of ten and above, and the distance between the peaks of the half-width at half height, and more.

Institute for Analytical Instrumentation of RAS, Saint-Petersburg

The probe for the simultaneous operation in the scanning ion conductance microscopy (SICM ) mode and in the tapping force mode has been proposed and studied. The numeric modeling of the image of the step on the surface of the dielectric sample in the SICM mode has been carried out. The experimental results which have been obtained by the scanning of the test sample are presented.

¹Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics
²Institute for Analytical Instrumentation of RAS, Saint-Petersburg

The features of electronic control circuits for the new design of active vibroprotection devices (AVD) have been investigated, those include the extended active frequency range and increased maximum vibration suppression coefficient. It was shown that the developed schematic and structural solutions allow using standard piezoelectric accelerometers in the control circuits of the new AVD. For these accelerometers high transmission coefficient is coupled with low resonance frequency and great parasitic signal caused by temperature changes.

Shubnikov Institute of Crystallography of RAS, Moscow

This paper presents the results of research and development of semiconductor optical amplifiers for the 840–1550 nm spectral range. The design of a semiconductor optical amplifier based on quantum-well heterostructures is presented. Investigations of the main characteristics (gain, saturation power, noise factor etc.) are discussed.

¹Joint-stock company "NOLATECH" (New Laser technology), Moscow
²POLYUS Research and Development Institute, Moscow

Dependence the Curie constant of magnetite nanoparticles suspension on magnetic field induction is experimentally investigated in the work. The Curie constant was defined by values of an induction and intensity of magnetic field in the suspension measured by a method of nuclear magnetic resonance. The received reduction of the Curie constant with growth of magnetic field induction is explained by disorder of nanoparticle size. In the assumption of uniform function of nanoparticles distribution on volumes satisfactory compliance of theoretical and experimental dependences of the Curie constant on magnetic induction is obtained.

Saint-Petersburg State Institute of Technology (Technical University)

The method of magnetic substance investigation based on registration of nuclear spin echo signal and simultaneous recording of magnetization curve is discussed in this work. Contributions from domains and domain walls were shown to result in complicated dependence of the signal on external field, which may be used in the studies of material characteristics. The results of measurements on lithium–zinc ferrite, demonstrating the qualitative accordance of the developed model and experiment, are given.

¹A.F. Ioffe Physical-Technical Institute RAS, Saint-Petersburg
²Institute for Analytical Instrumentation of RAS, Saint-Petersburg
³Saint-Petersburg State Polytechnic University

The work is devoted to the analysis of the stability of mathematically incorrect ellipsometry inverse problem, obtained on the basis of the earlier suggested method of successive approximations. It was shown, that one of the main causes of instability of the solution is the use of the traditional Box scheme in the computing process. The basic signs specifying instability of the solution of the inverse problem were determined. To increase the accuracy of computing process and maintenance of stability of the solution of the inverse problem Box complex method was significantly modified.

¹Sumy, Ukraine
²I.M. Sechenov First Moscow State Medical University

The paper reviews thermal mechanisms limiting the output optical power of laser diodes. Though the review is focused on the laser emitting light at 808 nm, the mechanisms considered are of general character and work in a wide range of the emission wavelengths. The catastrophic optical damage of the resonator mirrors and sublinearity of the light-current characteristics are two general mechanisms of the output power limitation. The paper discusses the nature and specific features of the catastrophic optical damage. The sublinearity of the light-current characteristics is, in turn, controlled by a number of factors. The most important among them are the rise of the threshold current and degradation of the differential quantum efficiency of the laser diodes with temperature, as well as the carrier leakage from the heterostructure followed by their non-radiation recombination at the ohmic contacts. The literature review is illustrated by the results of simulations of the laser structures operation.

¹ATC Semiconductor Devices, Saint-Petersburg
² STR Group — Soft-Impact, Ltd., Saint-Petersburg

The article considers the problem of signal optimum finding on background of reverberation hindrance, which is presented in the form of stochastic differential equation. On the basis of the obtained presentation the efficient algorithm for deterministic signal finding on the background of reverberation and the results of mathematical modeling are presented.

Popov Higher Naval Academy of Radio Electronics, Petrodvorets

The review of dispersion relations for general and partial scattering amplitudes regarding acoustic fields which are the consequence principle of causality adapted for classical fields, submitting wave equations is presented. Titchmarsh theorem which is a theoretical substantiation of dispersion relations is given as well as analytical S-matrix properties. The mentioned effects can be used in problems of acoustic dispersion to which the problem of calculation of radiation pressure is reduced, in particular in media with losses.

Institute for Analytical Instrumentation of RAS, Saint-Petersburg

The detailed deduction of the earlier expressions for calculation of radiation pressure in perfect fluid was made. The deduction of earlier missing corresponding expressions for a component of radiation pressure in a viscous medium caused by interaction of impinging and diffused waves was also realized. These expressions, being similar in shape with the expressions for perfect medium, will allow to use all techniques developed for the calculations of radiation pressure for perfect medium.

Institute for Analytical Instrumentation of RAS, Saint Petersburg

The structure and learning procedure is analyzed for neural network (NN) with manifold feedback structure grouped in several layers. The difference of this NN compared with recurrent networks is that temporal relations are provided by means of neurons arranged in three feedback layers that enrich the representation capabilities of NN. Feedback layers provide local and global recurrences via nonlinear processing elements. In feedback layers weighed sums of the delayed outputs of hidden and output layers are passed through certain activation functions and applied to the feedforward neurons via adjustable weights. The learning procedures for NN (including real time learning) are given that are based on back propagation through time algorithm. The "adjoint" model for NN with manifold recurrent structure is given that diminish the computation complexity of constructing NN learning algorithm.

SPbSPU, Saint-Petersburg

It is shown that use of spatial models of a trajectory of object in geographical coordinates reduces dimension of an estimated vector of navigating parameters, reducing computing expenses, and allows to solve essentially a problem of а posterior estimations of parameters of movement by independent measuring instruments at loss of satellite messages.

Rostov State Transport University, Rostov-on-Don