Peculiarities of gamma-quanta distribution at 20 TeV energy

The angular distribution of protons from the fragmentational region is analyzed. The gamma-quanta families are generated in a dense target by cosmic ray particles at 20 Tev energy. Families were found which had dense groups (spikes) of gamma-quanta where the rapidity/density is 3 times more than the average value determined for all registered families. The experimental data is compared with the results of artificial families simulation

A big data approach towards sarcasm detection in Russian

We present a set of deterministic algorithms for Russian inflection and automated text synthesis. These algorithms are implemented in a publicly available web-service www.passare.ru. This service provides functions for inflection of single words, word matching and synthesis of grammatically correct Russian text. Selected code and datasets are available at https://github.com/passare-ru/PassareFunctions/ Performance of the inflectional functions has been tested against the annotated corpus of Russian language OpenCorpora, compared with that of other solutions, and used for estimating the morphological variability and complexity of different parts of speech in Russian.Comment: arXiv admin note: substantial text overlap with arXiv:1706.0255

Spectro-Polarimetric Properties of Sunquake Sources in X1.5 Flare and Evidence for Electron and Proton Beam Impacts

The first significant sunquake event of Solar Cycle 25 was observed during the X1.5 flare of May 10, 2022, by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory. We perform a detailed spectro-polarimetric analysis of the sunquake photospheric sources, using the Stokes profiles of the FeI 6173A line, reconstructed from the HMI linear and circular polarized filtergrams. The results show fast variations of the continuum emission with rapid growth and slower decay lasting 3-4 min, coinciding in time with the hard X-ray impulses observed by the Konus instrument onboard the Wind spacecraft. The variations in the line core appeared slightly ahead of the variations in the line wings, showing that the heating started in the higher atmospheric layers and propagated downward. The most significant feature of the line profile variations is the transient emission in the line core in three of the four sources, indicating intense, impulsive heating in the lower chromosphere and photosphere. In addition, the observed variations of the Stokes profiles reflect transient and permanent changes in the magnetic field strength and geometry in the sunquake sources. Comparison with the radiative hydrodynamics models shows that the physical processes in the impulsive flare phase are substantially more complex than those predicted by proton and electron beam flare models currently presented in the literature.Comment: 15 pages, 12 figures, accepted for publication in ApJ, for associated mpeg file, see https://spaceweather.com/images2022/12may22/Sunquake_X1.5_flare_051022_1.mp

Electrotransport and magnetic properies of Cr-GaSb spintronic materials synthesized under high pressure

Electrotarnsport and magnetic properties of new phases in the system Cr-GaSb were studied. The samples were prepared by high-pressure (P=6-8 GPa) high-temperature treatment and identified by x-ray diffraction and scanning electron microscopy (SEM). One of the CrGa$_2$Sb$_2$ phases with an orthorhombic structure $Iba2$ has a combination of ferromagnetic and semiconductor properties and is potentially promising for spintronic applications. Another high-temperature phase is paramagnetic and identified as tetragonal $I4/mcm$

The "Horizon-T" Experiment: Extensive Air Showers Detection

Horizon-T is an innovative detector system constructed to study Extensive Air Showers (EAS) in the energy range above 10^16 eV coming from a wide range of zenith angles (0 - 85 degrees). The system is located at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level. It consists of eight charged particle detection points separated by the distance up to one kilometer as well as optical detector subsystem to view the Vavilov-Cerenkov light from the EAS. The time resolution of charged particles and Vavilov-Cerenkov light photons passage of the detector system is a few ns. This level of resolution allows conducting research of atmospheric development of individual EAS.Comment: Initial technical note for Horizon-T experiment, updated with recent detector upgrades, 11/2016. Updated 12/2017 with minor edits. Large upgrade will be in another articl

Mechanochemical Synthesis of Doped Apatite-type Lanthanum Silicates

In this paper, our results on mechanochemical synthesis of ATLS are summarized. The effect of the dopant type, its parent compound nature and amount of water on the Al and Fe-doped ATLS formation as well as possible phenomenological models of mechanism of apatitetype silicates synthesis are considered. As lanthanum and silicon sources, the La2O3 and SiO2∙nH2O have been taken. As dopant precursors, Fe- and Al-oxides and hydroxides, Fe(HCOO)3, SiO2 impregnated with nitrates have been taken. The apatite formation in the course of milling is studied by XRD, TEM, 29Si and 27Al MAS NMR, IR and UV-Vis spectroscopy. The key role of intermediate La(OH)3 formation, acid-base reactions and double-contact generation in the many-component mixtures due to aluminum or ferrosilicate formation for the rapid MCS of doped ATLS is shown. The doped ATLS formation via the topotactic mechanism was observed in the case of mixtures containing Al(OH)3 and SiO2 impregnated with nitrates. The water presence favours fast passing of acid-base reactions, however a large quantity of water may lead to ATLS formation via the activated mixture amorphization

Interplay between magnetism and superconductivity and appearance of a second superconducting transition in alpha-FeSe at high pressure

We synthesized tetragonal alpha-FeSe by melting a powder mixture of iron and selenium at high pressure. Subsequent annealing at normal pressure results in removing traces of hexagonal beta- FeSe, formation of a rather sharp transition to superconducting state at Tc ~ 7 K, and the appearance of a magnetic transition near Tm = 120 K. Resistivity and ac-susceptibility were measured on the annealed sample at hydrostatic pressure up to 4.5 GPa. A magnetic transition visible in ac-susceptibility shifts down under pressure and the resistive anomaly typical for a spin density wave (SDW) antiferromagnetic transition develops near the susceptibility anomaly. Tc determined by the appearance of a diamagnetic response in susceptibility, increases linearly under pressure at a rate dTc/dP = 3.5 K/GPa. Below 1.5 GPa, the resistive superconducting transition is sharp; the width of transition does not change with pressure; and, Tc determined by a peak in drho/dT increases at a rate ~ 3.5 K/GPa. At higher pressure, a giant broadening of the resistive transition develops. This effect cannot be explained by possible pressure gradients in the sample and is inherent to alpha-FeSe. The dependences drho(T)/dT show a signature for a second peak above 3 GPa which is indicative of the appearance of another superconducting state in alpha-FeSe at high pressure. We argue that this second superconducting phase coexists with SDW antiferromagnetism in a partial volume fraction and originates from pairing of charge carriers from other sheets of the Fermi surface