The contents and methods of teaching visual programming C#

The article describes the content of the section «Visual programming» within the discipline «Object-oriented and visual programming» for the system of Secondary Professional Education. Short methodical recommendations for the study of visual programming are presentedВ статье раскрывается содержание раздела «Визуальное программирование» в рамках дисциплины «Объектно-ориентированное и визуальное программирование» для системы СПО. Даются краткие методические рекомендации для изучения визуального программировани

Backward asymmetry of the Compton scattering by an isotropic distribution of relativistic electrons: astrophysical implications

The angular distribution of low-frequency radiation after single scattering by an isotropic distribution of relativistic electrons considerably differs from the Rayleigh angular function. In particular, the scattering by an ensemble of ultra-relativistic electrons obeys the law p=1-cos(alpha), where alpha is the scattering angle; hence photons are preferentially scattered backwards. We discuss some consequences of this fact for astrophysical problems. We show that a hot electron-scattering atmosphere is more reflective than a cold one: the fraction of incident photons which become reflected having suffered a single scattering event can be larger by up to 50 per cent in the former case. This should affect the photon exchange between cold accretion disks and hot coronae or ADAF flows in the vicinity of relativistic compact objects; as well as the rate of cooling (through multiple inverse-Compton scattering of seed photons supplied from outside) of optically thick clouds of relativistic electrons in compact radiosources. The forward-backward scattering asymmetry also causes spatial diffusion of photons to proceed slower in hot plasma than in cold one, which is important for the shapes of Comptonization spectra and the time delays between soft and hard radiations coming from variable X-ray sources.Comment: 20 pages, 3 figures, to appear in Astronomy Letters, added reference

Heating of gas inside radio sources to mildly relativistic temperatures via induced Compton scattering

Measured values of the brightness temperature of low-frequency synchrotron radiation emitted by powerful extragalactic sources reach 10^11--10^12 K. If some amount of nonrelativistic ionized gas is present within such sources, it should be heated as a result of induced Compton scattering of the radiation. If this heating is counteracted by cooling due to inverse Compton scattering of the same radio radiation, then the plasma can be heated up to mildly relativistic temperatures kT~10--100 keV. The stationary electron velocity distribution can be either relativistic Maxwellian or quasi-Maxwellian (with the high-velocity tail suppressed), depending on the efficiency of Coulomb collisions and other relaxation processes. We derive several easy-to-use approximate expressions for the induced Compton heating rate of mildly relativistic electrons in an isotropic radiation field, as well as for the stationary distribution function and temperature of electrons. We also give analytic expressions for the kernel of the integral kinetic equation (one as a function of the scattering angle and another for the case of an isotropic radiation field), which describes the redistribution of photons in frequency caused by induced Compton scattering in thermal plasma. These expressions can be used in the parameter range hnu<< kT<~ 0.1mc^2 (the formulae earlier published in Sazonov, Sunyaev, 2000 are less accurate).Comment: 22 pages, 7 figures, submitted to Astronomy Letter

ESR Study of Y<inf>2</inf>SiO<inf>5</inf>:Nd¹⁴³ Isotopically Pure Impurity Crystals for Quantum Memory

© 2017, Springer-Verlag Wien.Two Y2SiO5 single crystals doped with 0.001 at.% of the 143Nd3+ ion (sample I containing the only 28Si isotope) and (sample II with the natural abundance of silicon isotopes) were studied using magnetic resonance methods. The spin–spin and spin–lattice relaxation times were measured at 9.7 GHz between 4 and 10 K. It is established that three relaxation processes describe temperature dependences of the spin–lattice relaxation for both crystals. They are one-phonon, two-phonon Raman and two-phonon Orbach–Aminov relaxation processes. It is established that temperature dependence of spin–spin relaxation time differs for different hyperfine components of the electron paramagnetic resonance spectrum of neodymium ions and depends on the kind of the neodymium isotope (143Nd or 145Nd)

FEATURES OF DEVELOPMENT OF BIOGAS INDUSTRY

The paper presents the prospects for the use of biogas plants that solve energy and environmental problems. The paper analyzes the difference between the state support of the EU and Russia in the biogas industry. The paper considers two conditions for the development of this industry.В работе изложены перспективы использования биогазовых установок, решающих энергетические и экологические проблемы. В работе проанализировано различие государственной поддержки ЕС и России в биогазовой отрасли. В работе рассмотрено два условия для развития данной отрасли

Опыт лечения пациентов с гнойным сакроилеитом

This article presents the successful treatment experience of a patient with purulent sacroiliitis, complicated by an extensive retroperitoneal phlegmon. Due to the comprehensive approach, that includes two-stage surgical treatment and medication therapy, the patient was fully recovered.В данной статье представлен опыт успешного лечения пациентки с гнойным сакроилеитом, осложнившимся обширной забрюшинной флегмоной. Полного выздоровления больной удалось достичь благодаря комплексному подходу, включающему в себя двухэтапное хирургическое лечение и медикаментозную терапию

Compton Scattering Cross Section on the Proton at High Momentum Transfer

Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/ 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.Comment: 5 pages, 5 figure