316 research outputs found

    Pulsations and Long-Term Light Variability of Three Candidates to Protoplanetary Nebulae

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    We present new photometric data and analysis of the long-duration UBV photoelectric observations for three candidates to protoplanetary objects - F-supergiants with IR-excesses located at large galactic latitudes, IRAS 18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All three stars have revealed quasiperiodic low-amplitude variabilities caused by pulsations observed against the long-term trends of brightnesses. For IRAS 18095+2704=V887 Her we have found a pulsation period of 109 days and a linear trend of brightness under the constant colours if being averaged over the year timescale. The light curve of IRAS 19386+0155=V1648 Aql over 2000-2008 can be approximated by a wave with a main period of 102 days which is modulated by close frequency, with a period of 98 days, that results in brightness oscillations with a variable amplitude. V1648 Aql has also shown synchronous reddening together with a persistent rise of brightness in the V-band. IRAS 19500-1709=V5112 Sgr experiences irregular pulsations with the periods of 39 and 47 days. The long-term component of the variability of V5112 Sgr may be related to the binary character of this star.Comment: 11 pages, 6 figures, accepted for publication in Pis'ma Astron. Z

    Global regularity of weak solutions to quasilinear elliptic and parabolic equations with controlled growth

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    We establish global regularity for weak solutions to quasilinear divergence form elliptic and parabolic equations over Lipschitz domains with controlled growth conditions on low order terms. The leading coefficients belong to the class of BMO functions with small mean oscillations with respect to xx.Comment: 24 pages, to be submitte

    Modeling the spectrum of V4334 Sgr (Sakurai's Object)

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    Theoretical spectral energy distributions were computed for a grid of hydrogen-deficient and carbon-rich model atmospheres of T(eff) in the range of 5000-6250 K and log g = 1.0 - 0.0 by the technique of opacity sampling, taking into account continuous, molecular band and atomic line absorption. These energy distributions were compared with the spectrum of V4334 Sgr (Sakurai's object) of April, 1997 in the wavelength interval 300-1000 nm. We show that (1) the shape of the theoretical spectra depends strongly on T(eff) but only very weakly on the hydrogen abundance; (2) the comparison of the observed and computed spectra permits to estimate T(eff) approximately 5500 K for V4334 Sgr in April, 1997, and its interstellar reddening (plus a possible circumstellar contribution) E(B-V) approximately 0.70.Comment: 7 pages, 8 figures, LaTeX, accepted by Astronomy and Astrophysic

    Development of technological process of metal machining from stamping on 5-axis CNC milling machine

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    The technological process of compressor working blade production from stamping with minimum allowance for machining of the working part, on 5-axis CNC machine aimed at reducing the units of machine equipment has been developed. The tooling for basing the working part of the blade on the principle of six-point basing adapted to the design of the machine tool is realised. The geometrical parameters of the obtained blade were analysed with its mathematical model by 3D scanning method

    Controlling the type and the form of chip when machining steel

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    The type of the chip produced in the process of machining influences many factors of production process. Controlling the type of chip when cutting metals is important for producing swarf chips and for easing its utilization as well as for protecting the machined surface, cutting tool and the worker. In the given work we provide the experimental data on machining structural steel with implanted tool. The authors show that it is possible to control the chip formation process to produce the required type of chip by selecting the material for machining the tool surface

    Interrelation of intelligence features and academic progress at students of different psychological types

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    The article actualizes the problem of exception intelligence from the structure of the personality which is traditionally dropping out of a viewing field of domestic and foreign authors is updated. It is emphasized that in modern conditions cognitive and personal features in the set cause efficiency of activity. As a research objective determination of diagnostic potential of the typological questionnaire of MBTI, in particular, of its predictive opportunities concerning success of intellectual activity acts. A methodological basis is the theory Myers-Briggs. The key analyzed indicators: the academic progress, the IQ level, taking into account the making components, psychological type of the personality.В статье актуализируется проблема исключения интеллекта из структуры личности, традиционно выпадающая из поля зрения отечественных и зарубежных авторов. Подчеркивается, что в современных условиях когнитивные и личностные особенности в своей совокупности обусловливают эффективность деятельности. Целью исследования выступает определение диагностического потенциала типологического опросника MBTI, в частности, его прогностических возможностей относительно успешности интеллектуальной деятельности

    Observation of nonlinearity-controlled switching of topological edge states

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    We report the experimental observation of the periodic switching of topological edge states between two dimerized fs-laser written waveguide arrays. Switching occurs due to the overlap of the modal fields of the edge states from topological forbidden gap, when they are simultaneously present in two arrays brought into close proximity. We found that the phenomenon occurs for both strongly and weakly localized edge states and that switching rate increases with decreasing spacing between the topological arrays. When topological arrays are brought in contact with nontopological ones, switching in topological gap does not occur, while one observes either the formation of nearly stationary topological interface mode or strongly asymmetric diffraction into the nontopological array depending on the position of the initial excitation. Switching between topological arrays can be controlled and even completely arrested by increasing the peak power of the input signal, as we observed with different array spacings.Comment: 8 pages, 6 figure

    Peculiarities and variations in the optical spectrum of the post-AGB star V448Lac=IRAS22223+4327

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    Repeated observations with high spectral resolution acquired in 1998-2008 are used to study the temporal behavior of the spectral line profiles and velocity field in the atmosphere and circumstellar envelope of the post-AGB star V448Lac. Asymmetry of the profiles of the strongest absorption lines with low-level excitation potentials less 1eV and time variations of these profiles have been detected, most prominently the profiles of the resonance lines of BaII, YII, LaII, SiII. The peculiarity of these profiles can be explained using a superposition of stellar absorption line and shell emission lines. Emission in the (0;1) 5635A Swan band of the C2 molecule has been detected in the spectrum of V448Lac for the first time. The core of the Halpha line displays radial velocity variations with an amplitude ~8 km/s. Radial velocity variations displayed by weakest metallic lines with lower amplitudes, 1-2 km/s, may be due to atmospheric pulsations. Differential line shifts, 0 -- 8 km/s, have been detected on various dates. The position of the molecular spectrum is stationary in time, indicating a constant expansion velocity of the circumstellar shell, Vexp=15.2 km/s, as derived from the C2 and NaI lines.Comment: 19 pages, 8 figures, 1 tabl

    Influence of thyrotropic herbal remedy on vascular endothelium and thyroid gland structure in experimental hypothyroidism

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    The work presents evaluation of influence of plant preparation «Thyreoton-forte» on endothelium of vessels and morphological structure of thyroid gland in experimental hypothyreosis. Experimental hypothyreosis in rats was induced by administration of mercazolilum (10 mg/kg, intragastric introduction) during 28 days. The course administration of «Thyreoton-forte» (50,100 mg/kg, intragastric introduction) decreases the number of circulating endothelial cells (p < 0,05) and normalizes the structure of thyroid gland. Pharmacological effect of «Thyreoton-forte» is provided by protective influence in vascular endothelium and positive action on thyroid gland
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