Generation of spatio-temporal extreme events in noise-like pulses NPE mode-locked fibre laser

We experimentally study spatio-temporal generation of extreme events in the radiation of NPE mode-locked fibre laser generating noise-like pulses. We show that new pulses starts from high-intensity spatio-temporal structure which consist of mainly 3 subsequent pulses which are both separated over fast and slow evolution time. Statistical analysis of the noise-like pulse evolution over round-trips shows that the pulse width and intensity varies with a period of around 85 round-trips which does not change from pulse to pulse. The intensity probability density function has a heavy tail originated only from events of pulse formation

Pulse cathodo- and thermoluminescence of alumina ceramic with manganese

Alumina ceramics with manganese in concentration range 0.001-18 wt. % are synthesized. Luminescent properties of obtained ceramics at temperatures 1500-1700°C of sintering in vacuum are investigated. An increase in the manganese concentration leads to quenching of the pulse cathodoluminescence band at 420 nm and the main dosimetric peak at 460 K. The intensity of luminescence in the 676 nm band at manganese concentrations of more than 1 wt. % and the TL yield for all the observed peaks increase when annealing temperature rises. Sublinear increase in TL intensity with a growing dose is observed in the range of 3-1000 Gy in 460 and 620 K peaks. © Published under licence by IOP Publishing Ltd.The reported study was funded by RFBR according to the research project № 18-33-00085

Self-Induced Faraday Instability Laser

We predict the onset of self-induced parametric or Faraday instabilities in a laser, spontaneously caused by the presence of pump depletion, which leads to a periodic gain landscape for light propagating in the cavity. As a result of the instability, continuous wave oscillation becomes unstable even in the normal dispersion regime of the cavity, and a periodic train of pulses with ultrahigh repetition rate is generated. Application to the case of Raman fiber lasers is described, in good quantitative agreement between our conceptual analysis and numerical modelin

MOLECULAR GENETIC ANALYSIS AND SPECTRUM OF MUTATIONS IN KATG, INHA, RPOB GENES CODING DRUG RESISTANCE TO ISONIAZID AND RIFAMPICIN IN THOSE SUFFERING FROM TB/HIV CO-INFECTION

51 patients suffering from pulmonary tuberculosis with concurrent HIV infection (Group 1) had PCR testing in real time (ZAO Sintol, Moscow) of sputum samples in order to study the spectrum and prevalence of mutations in katG, inhA, rpoB genes coding drug resistance (DR) to isoniazid (H) and rifampicin (R). The control group included 70 HIV negative tuberculosis patients (Group 2). No significant differences in the number and spectrum of mutations in genes coding DR to H and R were found between two groups. However in Group 1 among clinical isolates with multiple drug resistance the confident prevalence of combination of mutations (rpoB Ser531- > Leu + katG Ser315- > Thr1) was found compared to Group 2 where the combined mutations of rpoB Ser531 > Leu + katG Ser315- > Thr1 + inhA 15 were registered more often where mutations in rpoB gene were combined with mutations simultaneously in two genes coding DR to H (katG + inhA)

The fractal method for analysis of macro models of the celestial bodies surface

© 2016, Education and Upbringing Publishing. All rights reserved.In case of building a model of physical surface of celestial body scientists are dealing with a system of parameters whose precision depends on an order of spherical functions series expansion. For significant precision a complicated figure forms and it is almost impossible to describe that with the classical approach. Thereby conducting a comparative analysis of the classical models built on the basis of various observations is quite complicated. The aim of this work is to apply a fractal analysis for topographic and selenographic models investigation. The approach based on fractal similarity of physical structures was used for classical models and models of the librational zone of the Moon, that had been built by expansion in a series of spherical functions in the dynamical coordinate system. As a result, the fractal dimensions of the librational zone of the Moon determined for the mentioned models at various angles have been obtained

Analysis of 430322 lunar occultations

© SGEM2017 All Rights Reserved. In the present work for the first time in the world practice 430322 occultations of stars by the Moon are analyzed. The relevance of the work is that the accuracy analysis of stars' proper motion in modern star catalogues can only be conducted using either observations of small planets or occultations, since only those observations are long-term and homogenous in time. When making the occultation database a comparative analysis has been used to study types and accuracy of occultation. For photoelectric observations were increased weights in this analysis, but only marginally, because the considerable contribution to the errors there are from the catalogue positions of the stars and the corrections for the outline of the Moon. The Russian occultations database has been independently analyzed. The photoelectric occultations database has been analyzed as well. In particular, there is a database of observations of occultations including 225121 objects taken from 1943 to 1980 in Greenwich observatory. But that database does not contain observations of occultations taken in Russia. The number of those observations is 7698. We adjusted this lack. We also keep constructing the full database of occultations using the Internet, printed editions, and data provided by the scientists of National Astronomical Observatory of Japan (NAOJ). As a result, the number of occultation observations was increased to 430322. Approximately 94.3% of those observations are taken by the visual method using telescope of comparatively small aperture. Around 11 % of them were taken by professional astronomers, the rest – by amateurs. About 5.7 % of all the observations are taken by photoelectric method, which implies recording an occultation with an accuracy of 0.001 sec. In conclusion it should be noted that the occultations database is going to be used for studying modern space catalogues, such as Hipparcos, UCAC 4, “Gaia” space mission etc

Spatial location of correlations in a random distributed feedback Raman fiber laser

Nonlinear interactions between different components of multiwavelength radiation are one of the main processes shaping properties of quasi-CW fiber lasers. In random fiber lasers, nonlinear influence may be more complicated, as there are no distinct longitudinal modes in radiation because of the random nature of the feedback. In this Letter, we experimentally characterize internal correlations in the radiation of a multiwavelength random distributed feedback fiber laser. An analysis of Pearson correlation functions allows us to spatially locate the area over the fiber laser length in which correlations are more likely to occur. This, in turn, leads us to the conclusion about the main mechanism of spectral correlations—the relative intensity noise transfer from the pump wave

Laminar-turbulent transition in Raman fiber lasers:a first passage statistics based analysis

Loss of coherence with increasing excitation amplitudes and spatial size modulation is a fundamental problem in designing Raman fiber lasers. While it is known that ramping up laser pump power increases the amplitude of stochastic excitations, such higher energy inputs can also lead to a transition from a linearly stable coherent laminar regime to a non-desirable disordered turbulent state. This report presents a new statistical methodology, based on first passage statistics, that classifies lasing regimes in Raman fiber lasers, thereby leading to a fast and highly accurate identification of a strong instability leading to a laminar-turbulent phase transition through a self-consistently defined order parameter. The results have been consistent across a wide range of pump power values, heralding a breakthrough in the non-invasive analysis of fiber laser dynamics