316 research outputs found
Pulsations and Long-Term Light Variability of Three Candidates to Protoplanetary Nebulae
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
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 .Comment: 24 pages, to be submitte
Modeling the spectrum of V4334 Sgr (Sakurai's Object)
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
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
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
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
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
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
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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