Modeling the Processes of Managing the Advertising Budget ofan Electronic Trading Platform

The paper presents the possibilities of using system-dynamic modeling to manage the advertising budget ofan electronic trading platform. A model has been developed and its mathematical description is given. Computer experiments have been carried out corresponding to various configurations of the advertising budget (distribution between different target groups) with the calculation of such efficiency indicators as profitability, total costs due to irrational advertising costs, and the cost ofattracting one client. © 2022 American Institute of Physics Inc.. All rights reserved.Simos T.E.Simos T.E.Simos T.E.Simos T.E.Tsitouras C

Технология термостимулированной диагностики анизотропии и оптических осей кристаллов

To implement the technology of thermally stimulated diagnostics of anisotropy and optical axes of crystals, the sample is thermostated at a temperature not exceeding the melting point, an electric field not exceeding the breakdown field is applied to the sample, polarization is produced for a time greater than the relaxation time at this temperature. After that, without disconnecting the electric field, cooling to the temperature of liquid nitrogen is performed, then the field is switched off, the sample is linearly heated to a temperature above the polarization temperature and the obtained thermally stimulated depolarization (TSD) spectra taken along and perpendicular to the optical axis of the sixth order C6 crystal are examined. When comparing the obtained spectra, the presence of anisotropy is determined, and the exact direction of the optical axes is determined by the magnitude and presence of the TSD maxima.Для осуществления технологии термостимулированной диагностики анизотропии и оптических осей кристаллов образец выдерживают при температуре, не превышающей температуру плавления, к образцу прикладывают электрическое поле, не превышающее поле пробоя, производят поляризацию в течение времени, большего времени релаксации при данной температуре. После этого, не отключая электрического поля, производится охлаждение до температуры жидкого азота, затем поле отключают, осуществляют линейный нагрев образца до температуры выше температуры поляризации и исследуют спектры термостимулированной деполяризации (ТСТД), полученные продольно и перпендикулярно оптической оси шестого порядка С6 кристалла. При сравнении полученных спектров определяют наличие анизотропии, а по величине и наличию максимумов ТСТД определяют точное направление оптических осей

Спектральная диагностика колебательных центров в кристаллах с водородными связями

In practical application of crystals in optoelectronics and laser technology it is necessary to know the direction of optical axes and types of oscillatory centers, which is a relevant and necessary condition. In this paper, the infrared spectra of transmission and absorption of hexagonal crystals of lithium iodate α-LiIO3, grown by open evaporation in H2O and D2O solutions, as well as natural lamellar crystals of phlogopite and muscovite monoclinic crystal are investigated. The band gap width of the investigated crystals is determined by transmission spectra. In the absorption spectra there were determined activation energy and wavelength of the oscillatory centers that are associated with the vibrations of protons, hydronium ions Н3О+, protium H+, OH groups and molecules HDO. The good correlation of the parameters of infrared spectra with the spectra of thermally stimulated depolarization currents and NMR spectra has shown. The possibility of diagnostics of types of oscillatory centers by means of infrared spectra is considered, which also allows to find out the direction of optical axes. The obtained results allow to use IR spectra to determine not only the types of vibrational centers, but also the presence of anisotropy of the crystal lattice of the studied crystals.При практическом применении кристаллов в оптоэлектронике и лазерной технике необходимо знать направления оптических осей и типов колебательных центров, что является актуальным и необходимым условием. Исследованы инфракрасные спектры пропускания и поглощения гексагональных кристаллов иодата лития α-LiIО3, выращенных методом открытого испарения в растворах H2O и D2O, а также природных пластинчатых кристаллов флогопита и мусковита моноклинной сингонии. По спектрам пропускания оценена ширина запрещенной зоны исследованных кристаллов. По спектрам поглощения определены энергия активации и длина волны колебательных центров, связанных с колебаниями протонов, ионов гидроксония Н3О+, протия Н+, групп ОН- и молекул HDO. Показана хорошая корреляция параметров инфракрасных спектров со спектрами термостимулированных токов деполяризации и спектров ядерно-магнитного резонанса. Рассмотрена возможность диагностики типов колебательных центров с помощью инфракрасных спектров, что также позволяет выяснить направление оптических осей. Полученные результаты позволяют использовать ИК-спектры для определения не только типов колебательных центров, но и наличия анизотропии кристаллической решетки исследуемых кристаллов

INTEGRAL Observations of SS433: Analysis of Precessional and Orbital X-ray Periodicities

Hard X-ray INT observations of SS 433 carried out during 2003-2005 years with an analysis of precessional and orbital variability is presented. The width of X-ray eclipse in the 25-50 keV range at the precessional phase $\psi=0.1$ (accretion disk is open to observer) is higher than that in the Ginga 18.4-27.6 keV range. This fact suggests existance the presence of hot extended corona around the supercritical accretion disk. Spectrum of hard X-rays in the range 10-200 keV does not change with the precessional phase which also suggests that hard X-ray flux is generated in the hot extended corona around the accretion disk. The parameters of this hot corona are: kT=23-25 keV, \tau = 1.8-2.8. Mass ratio estimated from the analysis of the ingress part of the eclipse light curve is in the range q=m_x/m_v=0.3-0.5.Comment: 5 pages, 10 figure

Unexpected catalytic activity of nanorippled graphene

Graphite is one of the most chemically inert materials. Its elementary constituent, monolayer graphene, is generally expected to inherit most of the parent material's properties including chemical inertness. Here we show that, unlike graphite, defect-free monolayer graphene exhibits a strong activity with respect to splitting molecular hydrogen, which is comparable to that of metallic and other known catalysts for this reaction. We attribute the unexpected catalytic activity to surface corrugations (nanoscale ripples), a conclusion supported by theory. Nanoripples are likely to play a role in other chemical reactions involving graphene and, because nanorippling is inherent to atomically thin crystals, can be important for two dimensional materials in general

On the role of the current loss in radio pulsar evolution

The aim of this article is to draw attention to the importance of the electric current loss in the energy output of radio pulsars. We remind that even the losses attributed to the magneto-dipole radiation of a pulsar in vacuum can be written as a result of an Ampere force action of the electric currens flowing over the neutron star surface (Michel, 1991, Beskin et al., 1993). It is this force that is responsible for the transfer of angular momentum of a neutron star to an outgoing magneto-dipole wave. If a pulsar is surrounded by plasma, and there is no longitudinal current in its magnetosphere, there is no energy loss (Beskin et al., 1993, Mestel et al., 1999). It is the longitudinal current closing within the pulsar polar cap that exerts the retardation torque acting on the neutron star. This torque can be determined if the structure of longitudinal current is known. Here we remind of the solution by Beskin, Gurevitch & Istomin (1993) and discuss the validity of such an assumption. The behavior of the recently observed "part-time job" pulsar B1931+24 can be naturally explained within the model of current loss while the magneto-dipole model faces difficulties.Comment: 4 pages, to appear in Astrophysics and Space Science, Special Issue: Isolated Neutron Stars. In the replaced paper we amended several misprints (coefficients in equations 12,14,15) and removed the excessive explanation for the boundary condition (4

An annular gap acceleration model for γ\gamma-ray emission of pulsars

If the binding energy of the pulsar's surface is not so high (the case of a neutron star), both the negative and positive charges will flow out freely from the surface of the star. The annular free flow model for $\gamma$-ray emission of pulsars is suggested in this paper. It is emphasized that: (1). Two kinds of acceleration regions (annular and core) need to be taken into account. The annular acceleration region is defined by the magnetic field lines that cross the null charge surface within the light cylinder. (2). If the potential drop in the annular region of a pulsar is high enough (normally the cases of young pulsars), charges in both the annular and the core regions could be accelerated and produce primary gamma-rays. Secondary pairs are generated in both regions and stream outwards to power the broadband radiations. (3). The potential drop in the annular region grows more rapidly than that in the core region. The annular acceleration process is a key point to produce wide emission beams as observed. (4). The advantages of both the polar cap and outer gap models are retained in this model. The geometric properties of the $\gamma$-ray emission from the annular flow is analogous to that presented in a previous work by Qiao et al., which match the observations well. (5). Since charges with different signs leave the pulsar through the annular and the core regions, respectively, the current closure problem can be partially solved.Comment: 11 pages 2 figures, accepted by Chinese Journal of Astronomy and Astrophysic

The theory of pulsar winds and nebulae

We review current theoretical ideas on pulsar winds and their surrounding nebulae. Relativistic MHD models of the wind of the aligned rotator, and of the striped wind, together with models of magnetic dissipation are discussed. It is shown that the observational signature of this dissipation is likely to be point-like, rather than extended, and that pulsed emission may be produced. The possible pulse shapes and polarisation properties are described. Particle acceleration at the termination shock of the wind is discussed, and it is argued that two distinct mechanisms must be operating, with the first-order Fermi mechanism producing the high-energy electrons (above 1 TeV) and either magnetic annihilation or resonant absorption of ion cyclotron waves responsible for the 100 MeV to 1 TeV electrons. Finally, MHD models of the morphology of the nebula are discussed and compared with observation.Comment: 33 pages, to appear in Springer Lecture Notes on "Neutron stars and pulsars, 40 years after the discovery", ed W.Becke