Methods of machine learning for the analysis of cosmic rays mass composition with the KASCADE experiment data

We study the problem of reconstruction of high-energy cosmic rays mass composition from the experimental data of extensive air showers. We develop several machine learning methods for the reconstruction of energy spectra of separate primary nuclei at energies 1-100 PeV, using the public data and Monte-Carlo simulations of the KASCADE experiment from the KCDC platform. We estimate the uncertainties of our methods, including the unfolding procedure, and show that the overall accuracy exceeds that of the method used in the original studies of the KASCADE experiment.Comment: 33 page

Network interaction in the tourist and recreational sphere

This article addresses questions on the formation of network structures in the tourism and recreational sphere because most prospective forms of interaction occur during the creation of a regional tourism product. The importance of networks in the solution of questions on the spatial localization of the tourist offer is noted, network designs in formation of tourism products are considered and the need to create substantially flexible networks for development of tourism that takes into account the available resources and the solution to the solution to the issue of redistribution of tourist stream

Digital supply chain management in the tourism and hospitality industry: trends and prospects

The article discusses the basics of the digital supply chain management, its characteristic features and scope of application are covered. The analysis of a condition of development of digital supply chain management in the world reflecting growth of its share in gross domestic product, and the Russian Federation for which characteristic is the state initiative of advance and development of digital processes, but not business structures is carried ou

Topological magnetic structures of MnGe: a neutron diffraction and symmetry analysis study

From new neutron powder diffraction experiments on the chiral cubic ($P2{_1}3$) magnet manganese germanide MnGe, we analyse all of the possible crystal symmetry-allowed magnetic superstructures that are determined successfully from the data. The incommensurate propagation vectors $k$ of the magnetic structure are found to be aligned with the [100] cubic axes, and correspond to a magnetic periodicity of about 30 $\r{A}$ at 1.8 K. Several maximal crystallographic symmetry magnetic structures are found to fit the data equally well and are presented. These include topologically non-trivial magnetic hedgehog and "skyrmion" structures in multi-$k$ cubic 3+3 and orthorhombic 3+2 dimensional magnetic superspace groups respectively, with either potentially responsible for topological Hall effect [1]. The presence of microstrain-like peak broadening caused by the transition to the magnetically ordered state would seem to favour a "skyrmion"-like magnetic structure, though this does not rule out the cubic magnetic hedgehog structure. We also report on a new combined mechanochemical and solid-state chemical route to synthesise MnGe at ambient pressures and moderate temperatures, and compare with samples obtained by the traditional high pressure synthesis

Digital supply chain management in the tourism and hospitality industry: trends and prospects

The article discusses the basics of the digital supply chain management, its characteristic features and scope of application are covered. The analysis of a condition of development of digital supply chain management in the world reflecting growth of its share in gross domestic product, and the Russian Federation for which characteristic is the state initiative of advance and development of digital processes, but not business structures is carried ou

New insights from old cosmic rays: A novel analysis of archival KASCADE data

Cosmic ray data collected by the KASCADE air shower experiment are competitive in terms of quality and statistics with those of modern observatories. We present a novel mass composition analysis based on archival data acquired from 1998 to 2013 provided by the KASCADE Cosmic ray Data Center (KCDC). The analysis is based on modern machine learning techniques trained on simulation data provided by KCDC. We present spectra for individual groups of primary nuclei, the results of a search for anisotropies in the event arrival directions taking mass composition into account, and search for gamma-ray candidates in the PeV energy domain.Comment: Proceedings of the 37th International Cosmic Ray Conference (ICRC2021), 12-23 July 2021, Berlin, Germany - Onlin

Применение автодинов в перспективных системах радиолокационного зондирования атмосферы

The results of studies of an autodyne transceiver (AT) for advanced radar sensing systems of the atmosphere are presented. A mathematical model of the APP has been developed, presented in the form of an oscillator with a single-circuit oscillatory system under the influence of a request signal from the radar. The analysis of the dynamics of signal reception in the beat mode, when the frequency of the received signal is outside the synchronization band, as well as in the capture mode, when the frequency of the request signal falls into the synchronization band of the AT. The noise and energy parameters and characteristics of the microwave generators used as an AT are investigated. Calculations of dynamic, noise and energy parameters and characteristics of the AT are performed depending on the choice of the type of conductivity characteristic of the active element and the position of the working point on it, as well as on the conditions of connection of the AT with the load. The experimental studies of the AT were carried out on the example of a serial transistor microwave module of the MRS-3MK radiosonde at a frequency of 1680 MHz. The description of the structural scheme of the AT for an aerological radiosonde operating in the beating mode is given. It is shown that the sensitivity of the AT to the request signal is determined by fluctuations in the amplitude of the microwave module and the bandwidth of the intermediate frequency amplifier. It is established that the sensitivity of the AT is minus 110...120 dB/W, for measuring the inclined range of 250...300 km is enough to have a radar transmitter with a pulse power of 50...100 W, while its average power corresponds to 0.05...0.1 W. Noskov V. Ya., Ivanov V. E., Gusev A. V., Ignatov K. A., Knyazev S. T., Kudinov S. I., Malygin I. V., Plokhikh O. V., Ponomarev O. P., Chernykh O. A. Application of autodynes in advanced systems of atmosphere radar sensing. Ural Radio Engineering Journal. 2022;6(1):11–53. (In Russ.) DOI: 10.15826/urej.2022.6.1.001. Представлены результаты исследований автодинного приемо-передатчика (АПП) для перспективных систем радиолокационного зондирования атмосферы. Разработана математическая модель АПП, представленная в виде автогенератора с одноконтурной колебательной системой, находящейся под воздействием запросного сигнала от РЛС. Выполнен анализ динамики приема сигналов в режиме биений, когда частота принимаемого сигнала находится за пределами полосы синхронизации, а также в режиме захвата, когда частота запросного сигнала попадает в полосу синхронизации АПП. Исследованы шумовые и энергетические параметры и характеристики используемых в качестве АПП СВЧ-генераторов. Выполнены расчеты динамических, шумовых и энергетических параметров и характеристик АПП в зависимости от выбора вида характеристики проводимости активного элемента и положения рабочей точки на ней, а также от условий связи АПП с нагрузкой. Экспериментальные исследования АПП выполнены на примере серийного транзисторного СВЧ-модуля радиозонда МРЗ-3МК на частоту 1680 МГц. Дано описание структурной схемы АПП для аэрологического радиозонда, работающего в режиме биений. Показано, что чувствительность АПП к запросному сигналу определяется флуктуациями амплитуды СВЧ-модуля и полосой пропускания усилителя промежуточной частоты. Установлено, что чувствительность АПП составляет минус 110...120 дБ/Вт, для измерения наклонной дальности 250...300 км достаточно иметь передатчик РЛС с импульсной мощностью 50...100 Вт, при этом средняя мощность его соответствует 0,05...0,1 Вт. Носков В. Я., Иванов В. Э., Гусев А. В., Игнатков К. А., Князев С. Т., Кудинов С. И., Малыгин И. В., Плохих О. В., Пономарев О. П., Черных О. А. Применение автодинов в перспективных системах радиолокационного зондирования атмосферы. Ural Radio Engineering Journal. 2022;6(1):11–53. DOI: 10.15826/urej.2022.6.1.001.

Application of aerological radar to determine the wind profile in the lower troposphere

Поступила: 20.03.2021. Принята в печать: 31.03.2021.Received: 20.03.2021. Accepted: 31.03.2021.В настоящее время для обеспечения оперативных прогнозов погоды и климата широко используются радиолокационные и радионавигационные системы аэрологического зондирования атмосферы с помощью запускаемых в атмосферу аэрологических радиозондов. Для получение оперативных данных о свободной атмосфере разработаны и эксплуатируются метеорологические радиолокационные системы различного назначения, обеспечивающие измерение метеорологических параметров неконтактными методами Одним из важнейших метеорологических параметров, является вертикальный профиль ветра. Для определения распределения направления и скорости ветра по высоте созданы специализированные радиолокаторы, позволяющие измерять динамические параметры ветра в реальном масштабе времени. В статье рассматривается возможность создания радиолокатора параметров ветра приземной атмосферы на основе модернизации серийного отечественного аэрологического радиолокатора. Технические характеристики радиолокатора – импульсная мощность передающего устройства, чувствительность приемного устройства, возможность точного управления диаграммой направленности антенны по угловым координатам позволяют принципиально обеспечить измерение ветра в приземном слое атмосферы. Основные вопросы модернизации связаны с необходимостью реализации когерентного режима работы приемопередающей системы радиолокатора и обеспечение когерентного накопления энергии отраженного сигнала в течение интервала статистической устойчивости атмосферы. Информация о ветре на измеряемой высоте оценивается по доплеровскому спектру отраженного сигнала от метеорологических неоднородностей. Возможность точного наведения антенны в течение сеанса зондировании позволяет определять вертикальный профиль ветра в диапазоне высот даже в условиях ясного неба.The work was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation under the project No. 0836-2020-0020.Currently, radar and radionavigation systems for aerological sounding of the atmosphere with the help of aerological radiosondes launched into the atmosphere are widely used to provide operational weather and climate forecasts. Meteorological radar systems for various purposes have been developed to obtain operational data on the free atmosphere. The systems are operated, providing measurement of meteorological parameters by noncontact methods. One of the most important meteorological parameters is the vertical wind profile. Specialized radars have been created to determine the distribution of wind direction and speed by altitude. They allow measuring the dynamic parameters of the wind in real time. The article considers the possibility of creating a radar for the wind parameters measuring he lower troposphere based on the modernization of a serial domestic aerological radar. Technical characteristics of the radar such as the pulse transmitting power, the sensitivity of the receiver, the ability to control the antenna radiation pattern accurately by angular coordinates make it possible to provide fundamental wind measurement in the lower troposphere. The main issues of modernization are related to the need of implementation of the coherent operation mode into the radar receiver and transmitter and ensuring the coherent energy storage of the reflected signal during the interval of statistical stability of the atmosphere. The information about the wind at the measured altitude is estimated from the Doppler spectrum of the signal reflected from meteorological inhomogeneities. The ability to accurately point the antenna during the sounding session allows determination of the vertical wind profile in the altitude range, even in clear sky conditions.Работа выполнена при финансовой поддержке Минобрнауки РФ по проекту 0836-2020-0020.The work was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation under the project No. 0836-2020-0020

Charge order above room-temperature in a prototypical kagome superconductor La(Ru1−x_{1-x}Fex_{x})3_{3}Si2_{2}

The kagome lattice is an intriguing and rich platform for discovering, tuning and understanding the diverse phases of quantum matter, which is a necessary premise for utilizing quantum materials in all areas of modern and future electronics in a controlled and optimal way. The system LaRu$_{3}$Si$_{2}$ was shown to exhibit typical kagome band structure features near the Fermi energy formed by the Ru-$dz^{2}$ orbitals and the highest superconducting transition temperature $T_{\rm c}$ ${\simeq}$ 7K among the kagome-lattice materials. However, the effect of electronic correlations on the normal state properties remains elusive. Here, we report the discovery of charge order in La(Ru$_{1-x}$Fe$_{x}$)$_{3}$Si$_{2}$ ($x$ = 0, 0.01, 0.05) beyond room-temperature. Namely, single crystal X-ray diffraction reveals charge order with a propagation vector of ($\frac{1}{4}$,0,0) below $T_{\rm CO-I}$ ${\simeq}$ 400K in all three compounds. At lower temperatures, we see the appearance of a second set of charge order peaks with a propagation vector of ($\frac{1}{6}$,0,0). The introduction of Fe, which is known to quickly suppress superconductivity, does not drastically alter the onset temperature for charge order. Instead, it broadens the scattered intensity such that diffuse scattering appears at the same onset temperature, however does not coalesce into sharp Bragg diffraction peaks until much lower in temperature. Our results present the first example of a charge ordered state at or above room temperature in the correlated kagome lattice with bulk superconductivity.Comment: 15 pages, 8 figure

Hidden magnetism uncovered in charge ordered bilayer kagome material ScV_6Sn_6

Charge ordered kagome lattices have been demonstrated to be intriguing platforms for studying the intertwining of topology, correlation, and magnetism. The recently discovered charge ordered kagome material ScV_6Sn_6 does not feature a magnetic groundstate or excitations, thus it is often regarded as a conventional paramagnet. Here, using advanced muon-spin rotation spectroscopy, we uncover an unexpected hidden magnetism of the charge order. We observe a striking enhancement of the internal field width sensed by the muon ensemble, which takes place within the charge ordered state. More remarkably, the muon spin relaxation rate below the charge ordering temperature is substantially enhanced by applying an external magnetic field. Taken together with the hidden magnetism found in AV_3Sb_5 (A = K, Rb, Cs) and FeGe kagome systems, our results suggest ubiqitous time-reversal symmetry-breaking in charge ordered kagome lattices.Comment: 9 pages, 4 figure