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Astrophysics

Circumstellar matter variability in the star MWC 614

Circumstellar matter variability in the star MWC 614

N. Z. Ismailov, H. N. Adigozalzade, U. Z. Bashirova

Memoirs of the Faculty of Physics 2018. N 1.

Abstract. The results of spectral monitoring of the Herbig Ae/Be star MWC 614 (HD 179218) at the 2 m telescope of ShAO have presented. It was discovered a wave like quasi-cyclic variations of radial velocities and equivalent widths with character time 10-12 days. Hα line profiles have shown an appearance and disappearance for nearly 20 days of additional emission components on the blue and red wings. On the variability of profiles of various spectral lines we have concluded that for time to time it was observed an accretion and outflow of the disc matter, what perhaps is an indicated of the presence a magnetosphere of this young star.

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Theoretical and mathematical physics

The higgs bosons production in arbitrary polarized electron-positron colliding beams

The higgs bosons production in arbitrary polarized electron-positron colliding beams

S. K. Abdullayev, M. S. Gojayev

Memoirs of the Faculty of Physics 2018. N 1.

The production of Higgs bosons in arbitrary polarized electron-positron collisions has been investigated e^–e^+→ZH_SМ, e^–e^+→Zh, e^–e^+→ZH, e^–e^+→HA and e^–e^+→H^-H^+, where H_SМ is the Higgs boson of the Standard Model,а h, H, A, H^- and H^+ are the analogues of the Higgs boson, which may take place in the MSSM. We have calculated the cross sections and asymmetries A(varphi) and A_RL. The typical peculiarities of the cross sections and asymmetries of the processes as a function of the energy of the e^–e^+-beams and the Higgs bosons mass are investigated.

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Physics of nuclei and elementary particles

Empirical estimate of np-pairing magnitude in N=Z nuclei

Empirical estimate of np-pairing magnitude in N=Z nuclei

B. S. Ishkhanov$^{1,2}$, S. V. Sidorov$^1$, T. Yu. Tretyakova$^2$

Memoirs of the Faculty of Physics 2018. N 1.

In studies of neutron-proton pairing the empirical evaluations based on nuclear masses are of particular importance. In the current work, various mass relations are analysed by the example of N=Z nuclei and essentially different formulas used for estimation of np-pairing energy in self-conjugate nuclei are shown to yield similar results. Correlations between the obtained values and the spectra of isobaric analogous states indicate that mass relations may be used to describe the isovector (T=1) component of np-pairing to sufficient accuracy, providing however little or no information regarding the isoscalar component T=0.

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Influence of the energy spectrum of an electron beam on the estimation of its energy by the method of attenuation of bremsstrahlung by an absorbing barrier

Influence of the energy spectrum of an electron beam on the estimation of its energy by the method of attenuation of bremsstrahlung by an absorbing barrier

L. Yu. Ovchinnikova$^{1,2}$, V. I. Shvedunov$^{1,2}$

Memoirs of the Faculty of Physics 2018. N 1.

The procedure for measuring the energy of a nonmonochromatic electron beam by the method of attenuating bremsstrahlung by an absorbing barrier is simulated using the analytical expression for the bremsstrahlung spectrum. The energy value measured by this method is compared with the mean energy and energy of the maximum of the electron beam spectrum. It is shown that the energy estimate obtained by the attenuation barrier method depends on the form of the electrons energy spectrum and is closer to the average energy than to the energy of the maximum of the spectrum, which, as a rule, is the main optimized parameter in calculating beam dynamics in the accelerator.

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Radiophysics, electronics, acoustics

Simulation and measurement of low-sidelobe phased antenna array with circular polarization

Simulation and measurement of low-sidelobe phased antenna array with circular polarization

G. M. Lu$^1$, P. N. Zakharov$^2$, A. F. Korolev$^3$

Memoirs of the Faculty of Physics 2018. N 1.

Two shapes of antenna elements providing circular polarization in the far field have been investigated and compared; feeder network providing Chebyshev distribution of currents and uniform distribution of phases has been designed for 4x4 arrays; phased arrays with modified square and circular patches have been designed and compared, providing sidelobe reduction up to -26 dB; experimental tests of the trial array have been performed.

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Optics and spectroscopy. Laser physics

Laser-induced modification of aluminum micropowders in selective laser melting mode

Laser-induced modification of aluminum micropowders in selective laser melting mode

F. V. Kashaev$^1$, D. V. Shuleiko$^1$, S. V. Zabotnov$^1$, A. V. Skobelkina$^1$, A. K. Petrov$^2$, A. V. Chetvertukhin$^3$, P. V. Evdokimov$^4$, A. V. Garshev$^4$, V. I. Putlayev$^4$

Memoirs of the Faculty of Physics 2018. N 1.

Selective laser melting of the powders of AlSi10Mg alloy, characterized various sizes and shapes of particles, has been carried out in vacuum and argon by laser pulses with submillisecond duration. As a result of this modification, the structures are formed with porosity, depending both on the geometric parameters of the particles in the initial powders and on the atmosphere in which irradiation was carried out. For the first time by means of the Raman spectroscopy a considerable change in the mechanical stresses and fraction of crystalline state silicon in the studied structures before and after selective laser melting was registered.

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Condensed matter physics

Hopping transport of holes in CuCrO2 ceramic samples doped with magnesium

Hopping transport of holes in CuCrO2 ceramic samples doped with magnesium

V. G. Kytin$^1$, V. A. Kulbachinskii$^1$, D. Yu. Kondratieva$^1$, A. V. Pavlikov$^2$, A. N. Grigoriev$^3$, A. S. Mankevich$^3$, I. E. Korsakov$^3$

Memoirs of the Faculty of Physics 2018. N 1.

Сonductivity of copper chromite samples doped with magnesium synthesized by solid state method was investigated in wide temperature range. Crystal structure of the samples was determined by X-ray diffraction and confirmed by Raman spectroscopy. P-type of conductivity was confirmed by positive sign of Seebeck coefficient. Analysis of temperature dependencies of conductivity showed that observed conductivity is hopping for magnesium content from 0 to 6 %. Estimates of localization length and density of states at Fermi energy were obtained from temperature dependencies of conductivity.

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Chemical physics, physical kinetics, and plasma physics

Analysis of characteristics of the magnetotail current sheet during geomagnetic perturbations

Analysis of characteristics of the magnetotail current sheet during geomagnetic perturbations

V. I. Djmrin$^1$, H. V. Malova$^2$, V. Yu. Popov$^1$

Memoirs of the Faculty of Physics 2018. N 1.

On the base of numerical simulation the evolution of current sheet (CS) in the Earth’s magnetotail during geomagnetic perturbations is investigated. The evolution of the pressure tensor in the process of CS thinning to extremely thin configuration playing a key role in large-scale geomagnetic perturbations is considered. It is shown in a frame of numerical experiment that at an early stage the CS is formed with thickness about 8-10 Larmor proton radii and gyrotropic pressure distribution. This stage is characterized by plasma drift motion to CS center and to the Earth, and can be well described by the Chew-Goldberger-Low approximation. At the later stage the extremely thin current sheet is formed in which plasma pressure tensor becomes anisotropic. Estimates of characteristic timescales of the system evolution are made and the agreement with the available experimental data is shown.

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Biophysics and medical physics

The Effect of Saffron Extract on the Thiol Group in the Organism Exposed to 2Gy and 4Gy X-ray Irradiation

The Effect of Saffron Extract on the Thiol Group in the Organism Exposed to 2Gy and 4Gy X-ray Irradiation

U. F. Hashimova$^1$, I. A. Rzayeva$^2$

Memoirs of the Faculty of Physics 2018. N 1.

It was shown that X-ray irradiation of 4 Gy and 2 Gy dose leads to the studied thiol groups activity suppression in various brain structures. Also it has been established that, with the preset of saffron extract, X-ray irradiation in most cases doesn't lead to the studied thiol group activity suppression. Contrary to that, the antioxidant promotes their activity increase in the brain struc-tures we have studied.

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Teaching methods

Practical work on physics as a whole scientific research based on open data

Practical work on physics as a whole scientific research based on open data

I. V. Kuznetsova$^1$, M. E. Prokhorov$^2$

Memoirs of the Faculty of Physics 2018. N 1.

The article describes a new model of practical work in physics on the basis of modern scientific data placed in the public domain. It assesses the frequency of asteroids falling to Earth by counting the number of craters on the Moon and discusses the various mechanisms of the formation of craters depending on the parameters. This work has several significant methodical benefits over traditional teaching labs. Firstly, the work is dedicated to the relevant scientific problem. Secondly, it forms in students an idea of the diverse relationships between studied objects and scientific methodology that takes into account some aspects of the phenomenon and discarded others. Third, the work has a multidisciplinary. It uses reference data from different branches of physics, geology and astronomy. Practical elaboration has a distinct visibility and it offers the possibility to vary the data materials used in the work. The proposed laboratory work is universal, does not require expensive equipment to carry it out, and can be used in distance education.

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