Time filter

Source Type

Liski, Russia

The Ryazan State University named for S. A. Yesenin is a university in Ryazan, Ryazan Oblast, Russia. It was founded in 1915. It bears the name of Russian poet Sergei Yesenin, who grew up in the region. Wikipedia.

Safonova A.V.,Ryazan State University
CriMiCo 2014 - 2014 24th International Crimean Conference Microwave and Telecommunication Technology, Conference Proceedings | Year: 2014

The influence of DOA algorithm structure on efficiency of estimation of angular coordinates is studied Examples of the array antenna use with the elements arranged in parallel, and L- and 2d-L-shaped antenna arrays, are discussed. Simulation and comparative analysis results for the proposed algorithms are presented. © 2014 CriMiCo'2014 Organizing Committee, CrSTC. Source

Douglas D.J.,University of British Columbia | Konenkov N.V.,Ryazan State University
Rapid Communications in Mass Spectrometry | Year: 2014

RATIONALE Auxiliary dipole excitation is widely used to eject ions from linear radio-frequency quadrupole ion traps for mass analysis. Linear quadrupoles are often constructed with round rod electrodes. The higher multipoles introduced to the electric potential by round rods might be expected to change the ion ejection process. We have therefore investigated the optimum ratio of rod radius, r, to field radius, r0, for excitation and ejection of ions. METHODS Trajectory calculations are used to determine the excitation contour, S(q), the fraction of ions ejected when trapped at q values close to the ejection (or excitation) q. Initial conditions are randomly selected from Gaussian distributions of the x and y coordinates and a thermal distribution of velocities. The N=6 (12 pole) and N=10 (20 pole) multipoles are added to the quadrupole potential. Peak shapes and resolution were calculated for ratios r/r0 from 1.09 to 1.20 with an excitation time of 1000cycles of the trapping radio-frequency. RESULTS Ratios r/r0 in the range 1.140 to 1.160 give the highest resolution and peaks with little tailing. Ratios outside this range give lower resolution and peaks with tails on either the low-mass side or the high-mass side of the peaks. This contrasts with the optimum ratio of 1.126-1.130 for a quadrupole mass filter operated conventionally at the tip of the first stability region. With the optimum geometry the resolution is 2.7 times greater than with an ideal quadrupole field. Adding only a 2.0% hexapole field to a quadrupole field increases the resolution by a factor of 1.6 compared with an ideal quadrupole field. Addition of a 2.0% octopole lowers resolution and degrades peak shape. With the optimum value of r/r0, the resolution increases with the ejection time (measured in cycles of the trapping rf, n) approximately as R0.5=6.64n, in contrast to a pure quadrupole field where R0.5=1.94n. CONCLUSIONS Adding weak nonlinear fields to a quadrupole field can improve the resolution with mass-selective ejection of ions by up to a factor of 2.7. The optimum ratio r/r0 is 1.14 to 1.16, which differs from the optimum ratio for a mass filter of 1.128-1.130. Copyright © 2014 John Wiley & Sons, Ltd. Source

Romanchuk V.A.,Ryazan State University
IOP Conference Series: Materials Science and Engineering | Year: 2015

The article discusses issues in developing algorithms and software for specialized computing devices based on neuroprocessors, to be used in automatic control of electric- mechanical system modules (in this case study, a hexapod) in a mode that is close to real-time. The practical implementation employed an NM6406 neuroprocessor based on an MC 51.03 tool module and an MB 77.07 microcomputer, developed by the Module Research Centre. © Published under licence by IOP Publishing Ltd. Source

Douglas D.J.,University of British Columbia | Konenkov N.V.,Ryazan State University
Rapid Communications in Mass Spectrometry | Year: 2014

RATIONALE For mass analysis, linear quadrupole ion traps operate with dipolar excitation of ions for either axial or radial ejection. There have been comparatively few computer simulations of this process. We introduce a new concept, the excitation contour, S(q), the fraction of the excited ions that reach the trap electrodes when trapped at q values near that corresponding to the excitation frequency. METHODS Ion trajectory calculations are used to calculate S(q). Ions are given Gaussian distributions of initial positions in x and y, and thermal initial velocity distributions. To model gas damping, a drag force is added to the equations of motion. The effects of the initial conditions, ejection Mathieu parameter q, scan speed, excitation voltage and collisional damping, are modeled. RESULTS We find that, with no buffer gas, the mass resolution is mostly determined by the excitation time and is given by R~dβdqqn, where β(q) determines the oscillation frequency, and n is the number of cycles of the trapping radio frequency during the excitation or ejection time. The highest resolution at a given scan speed is reached with the lowest excitation amplitude that gives ejection. The addition of a buffer gas can increase the mass resolution. The simulation results are in broad agreement with experiments. CONCLUSIONS The excitation contour, S(q), introduced here, is a useful tool for studying the ejection process. The excitation strength, excitation time and buffer gas pressure interact in a complex way but, when set properly, a mass resolution R0.5 of at least 10,000 can be obtained at a mass-to-charge ratio of 609. Copyright © 2014 John Wiley & Sons, Ltd. Source

Douglas D.J.,University of British Columbia | Konenkov N.V.,Ryazan State University
European Journal of Mass Spectrometry | Year: 2012

If large numbers of ions are stored in a linear quadrupole ion trap, space charge causes the oscillation frequencies of ions to decrease. Ions then appear at higher apparent masses when resonantly ejected for mass analysis. In principle, to calculate mass shifts requires calculating the positions of all ions, interacting with each other, at all times, with a self-consistent space charge field. Here, we propose a simpler model for the ion cloud in the case where mass shifts and frequency shifts are relatively small (ca 0.2% and 0.4%, respectively), the trapping field is much stronger (ca × 102) than the space charge field and space charge only causes small perturbations to the ion motion. The self-consistent field problem need not be considered. As test ions move with times long compared to a cycle of the trapping field, the motion of individual ions can be ignored. Static positions of the ions in the cloud are used. To generate an ion cloud, trajectories of N (ca 10,000) ions are calculated for random times between 10 and 100 cycles of the trapping radio frequency field. The ions are then distributed axially randomly in a trap of length four times the field radius, r0. The potential and electric field from the ion cloud are calculated from the ion positions. Near the trap center (distances r < 0.1r0), the potential and electric fields from space charge are not cylindrically symmetric, but are quite symmetric for greater values of r. Trajectories of test ions, oscillation frequencies and mass shifts can then be calculated in the trapping field, including the space charge field. Mass shifts are in good agreement with experiments for reasonable values of the initial positions and speeds of the ions. Agreement with earlier analytical models for the ion cloud, based on a uniform occupation of phase space, or a thermal (Boltzmann) distribution of ions trapped in the effective potential [D. Douglas and N.V. Konenkov, Rapid Commun. Mass Spectrom. 26, 2105 (2012)]1 is quite good. All three models give similar electric fields to match experimental mass shifts. © 2012 IM Publications LLP. All rights reserved. Source

Discover hidden collaborations