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111.
K. P. Tsvetkova M. K. Tsvetkov T. P. Sergeeva A. V. Sergeev 《Kinematics and Physics of Celestial Bodies》2009,25(5):269-276
The latest version of the Wide-Field Plate Database Catalogue of Wide-Field Plate Archives (April 2008) contains 43 archives
stored at some Ukrainian observatories, namely, at the Main Astronomical Observatory of the National Academy of Sciences of
Ukraine (Golosiiv, Kyiv), at the Crimean Astrophysical Observatory (Nauchnyi and Simeiz), at the Kyiv, L’viv, and Odesa University
Observatories, and at the Mykolaiv Observatory. About 126000 plates were obtained from 1898 to 2005 in the framework of the
following observing programmes: Solar System Bodies Observations, Observations of Variable Stars, Investigations of the Emission
Nebulae and Connected Stars, Spectral Classification of the Stars and Determination of the Stellar Absorption in the Direction
of the Emission Nebulae, Photographic Survey of the Northern Sky (FON), Investigation of the Kinematics and Structure of the
Main Meridian Section of our Galaxy (MEGA), Observation of Selected Reference Stars, Artificial Satellites Observations and
other. At the moment the basic information on 12609 plates from 13 plate archives of the Main Astronomical Observatory and
Crimean Astrophysical Observatory is included into the Wide-Field Plate Database Catalogue of Wide-Field Plate Indexes (Sofia,
Bulgaria). The plate digitization is just started with flatbed scanners. Some illustrations of the potential of the Ukrainian
plate archives for future reusage are given and some compiled plate catalogues are presented on the basis of data from the
Wide-Field Plate Database. 相似文献
112.
B. V. Belyatsky N. V. Rodionov A. V. Antonov S. A. Sergeev 《Doklady Earth Sciences》2011,438(2):770-774
This study presents new results on zircons from the enderbite-charnockite rocks of Enderby Land, East Antarctica. U-Pb age
of 3981 ± 8 Ma (SIMS SHRIMP II), which was first obtained for a protolith of massive enderbites from Aker Peaks, eastern Napier
Mts, suggests that the existence of sialic crust in the study area at 4 Ga. Although there was only one magmatic zircon (of
150 grains analyzed) in the study area known with the oldest age, its significance cannot be overestimated, since it may indirectly
evidence the existence of an Early Archean crustal block with a minimum age of 4 Ga, which extends for over 300 km across
Enderby Land from its western to eastern part. Based on the U-Pb systematics, REE and trace element distributions in zircons
from charnockite and enderbite gneisses, high-aluminous gneisses, and basic granulites, we first revealed that an early high-temperature
metamorphic event accompanied by the emplacement of granodiorite intrusions occurred in the vicinity of Aker Peaks at 3620–3630
Ma. Although the 2850–3050 metamorphic overprints are clearly observed in some other areas of Enderby Land and are widely
considered to be of critical importance on a regional scale, their metamorphic signatures are apparently absent from the U-Pb
systematics of the studied zircon, thus suggesting the presence of similar old zircons in the study area. At the same time,
all samples in this study record a 2480–2550 Ma granulite-amphibolite facies overprint represented as new zircon growths or
recrystallization of earlier phases. 相似文献
113.
A. E. Vol’vach L. N. Vol’vach A. M. Kut’kin M. G. Larionov M. Villata K. M. Panteri A. Lahteenmaki M. Tornikoski P. Savolainen G. Tammi A. F. Aller H. D. Aller S. G. Sergeev V. T. Doroshenko Yu. S. Efimov S. A. Klimanov S. V. Nazarov G. V. Borman A. B. Pushkarev V. I. Zhdanov E. V. Fedorova I. B. Vavilova N. G. Chesnok 《Astronomy Reports》2011,55(7):608-615
Long-term monitoring data at five radio frequencies from 4.8 to 37 GHz obtained at the Crimean Astrophysical Observatory, Metsahovi Radio Observatory of Aalto University, and the University of Michigan Radio Astronomy Observatory are used to analyze variations of the flux of the Active Galactic Nucleus (AGN) 3C 454.3. The dynamical characteristics of the three latest powerful flares from 2004 to 2010 are analyzed in detail. Observations in the gamma-ray (0.1–300 GeV), X-ray (2–10 kev, 15–50 keV), and optical are also used. Delays in the development of flares at different frequencies are derived. An empirical frequency dependence for the delays of flares from the gamma-ray to the radio is determined, which can be fit using a logarithmic low and remains the same from flare to flare. The physical characteristics of the central region of the AGN 3C 454.3 are used to estimate the size of its Strömgren sphere, taking into account the relevant mechanisms for heating and cooling the medium, as well as the adopted laws for the variation of the density and temperature with distance from the source of ionization. A model for the location of the radiation regions in the jet at various frequency ranges during the development of flares is proposed. 相似文献
114.
An investigation undertaken recently by the Division of Regional Geoecology and Marine Geology of the Karpinsky All-Russian
Research Geological Institute in the coastal zones of the Eastern Gulf of Finland allowed finding some specific relief forms
of both near-shore bottom topography and shoreline shape. First of all, among the most interesting objects, the sand ridges
on the surface of submarine terrace (between Repino locality and Cape Lautaranta) should be mentioned. These ridges are elongated
at an angle to the shoreline and are located beyond the limits of wave action. The other interesting morphological type is
represented by longshore sand waves up to some hundreds of meters long and some tens of meters wide near the Bol’shaya Izhora
locality. Longshore sand waves move along the southern coast of the gulf, this causing alteration of erosion and accretion
zones and leading to formation and degradation of the sand spits. Shore-face-connected ridges are believed to develop under
the action of drift currents generated during the passage of deep west cyclones. It is shown that the ridge turned toward
the current gives rise to a convergence of the cross-shore flows over the crest and provokes a shift of the maximum velocity
toward the front side of the structure. Associated changes in sediment discharges result in accumulation and growth of the
ridge. The origin of wavelike features in the shoreline contour (longshore sand waves) is due to a very oblique wave approach
caused by predominance of the west winds blowing along the axis of the gulf. Under these conditions a small perturbation of
the shoreline contour is shown to manifest a trend to increase with time. 相似文献
115.
V. V. Bakhanov N. A. Bogatov S. N. Vlasov V. I. Kazakov E. V. Koposova D. A. Sergeev 《Oceanology》2011,51(4):543-553
This paper presents the results of laboratory measurements of surface currents over a sphere moving in the fluid column based
on the particle tracing velocimetry. A theoretical model of the fluid flowing around the sphere is presented. The experimental
data are compared with the results of theoretical calculations. It is shown that, at low tow speeds of the sphere, the experimentally
measured current velocities exceed the velocities calculated from the theoretical model. At greater tow velocities when generation
of surface waves by the sphere was observed in the experiment, the experimental data agree well with the results of the theoretical
calculations. 相似文献
116.
V. T. Doroshenko S. G. Sergeev N. I. Merkulova E. A. Sergeeva Yu V. Golubinsky V. I. Pronik N. N. Okhmat 《Astrophysics》2005,48(2):156-178
Results are presented from CCD BVRI observations of comparison stars in the neighborhoods of 22 galaxies with active nuclei having right ascensions ranging from 0 to 12 hours, of which 19 are Seyfert galaxies. The observed stars have magnitudes ranging from V=11 to V=17. For stars brighter than V=14 the typical photometic error is 0.01m. The B, V, Rc, and Ic magnitudes of most of these stars were not known previously. 14′×14′ finding charts are included. These results can be used for differential photometry of the AGNs in the B, V, Rc, and Ic bands.__________Translated from Astrofizika, Vol. 48, No. 2, pp. 191–211 (May 2005). 相似文献
117.
V. N. Sergeev N. M. Chumakov M. A. Semikhatov N. G. Vorob’eva 《Stratigraphy and Geological Correlation》2013,21(1):1-7
Microfossils from silicified varieties of cap dolomites crowning the section of the tillite-bearing Lower Vendian (Ediacaran) Churochnaya Formation in the Polyudov Range (North Urals) are characterized. These microfossils are the first to be found from Vendian sections of the region and from all the terminal post-glacial sediments, one of the most significant global glaciation Marinoan of the African Glacial Era, when glaciers reached the equator. They are represented by remains of hormogonian and chrococcacean cyanobacteria as well as possible green filamentous algae. This microbiotic assemblage is of relatively low diversity, being composed of taxa with wide stratigraphic ranges characteristic of Proterozoic conservative microbiotas developed in shallow-water siliceous-carbonate facies. The lack of phytoplanktonic microfossils in this biota including Pertatataka-type acanthomorphic acritarchs or Ediacaran Complex Acanthomorph Palynoflora (ECAP) is also consistent with the conclusion on shallow-water deposition of the Churochnaya Formation. Moreover, most cyanobacteria representatives occurring in the latter are characteristic of shallow-water arid environments that confirm a theory of significant temperature increase during accumulation of the cap dolomites after termination of the above-mentioned glaciation. In addition to these microfossils, the cap dolomite member of the Churochnaya Formation contains filamentous and coccoidal pseudofossils formed under influence of post-sedimentary fluids. In their morphometric parameters, they resemble structures described from Archean sections as microfossil remains, which may be a key to interpreting their nature. 相似文献
118.
G. S. Ripp I. A. Izbrodin A. G. Doroshkevich E. I. Lastochkin M. O. Rampilov S. A. Sergeev A. V. Travin V. F. Posokhov 《Petrology》2013,21(4):375-392
This paper reports the results of Rb-Sr, 40Ar-39Ar, and U-Pb geochronological investigations for igneous and metamorphic rocks from the regions of the Oshurkovo basic massif. It was shown that the gabbro-syenite-granite complex that was formed there is similar to the bimodal basalt-rhyolite series of volcanic associations. Three major stages of magmatic activity were recognized: syenite-granite (132–127 Ma), basic (126–117 Ma), and granite (121–112 Ma). The silicic igneous rocks were formed owing to anatexis under the influence of heat released from the parent chamber of alkaline gabbroids. 相似文献
119.
Uwe Hoffmann Christoph Breitkreuz Karel Breiter Sergey Sergeev Klaus Stanek Marion Tichomirowa 《International Journal of Earth Sciences》2013,102(1):73-99
Nine SHRIMP U/Pb ages on zircon and two Pb/Pb single zircon ages have been determined from Late Paleozoic volcanic rocks from Saxony and northern Bohemia. Samples came from the Teplice-Altenberg Volcanic Complex, the Meissen Volcanic Complex, the Chemnitz Basin, the Döhlen Basin, the Brandov-Olbernhau Basin, and the North Saxon Volcanic Complex. The Teplice-Altenberg Volcanic Complex is subdivided into an early Namurian phase (Mikulov Ignimbrite, 326.8 ± 4.3 Ma), thus older than assumed by previous studies, and a late caldera-forming phase (Teplice Ignimbrite, 308.8 ± 4.9 Ma). The age of the latter, however, is not well constrained due to a large population of inherited zircon and possible hydrothermal overprint. The Leutewitz Ignimbrite, product of an early explosive volcanic episode of the Meissen Volcanic Complex yielded an age of 302.9 ± 2.5 Ma (Stephanian A). Volcanic rocks intercalated in the Brandov-Olbernhau Basin (BOB, 302 ± 2.8 Ma), Chemnitz Basin (CB, 296.6 ± 3.0 Ma), Döhlen Basin (DB, 296 ± 3.0 Ma), and the North Saxon Volcanic Complex (NSVC, c. 300–290 Ma) yielded well-constrained Stephanian to Sakmarian ages. The largest Late Paleozoic ignimbrite-forming eruption in Central Europe, the Rochlitz Ignimbrite, has a well-defined middle Asselian age of 294.4 ± 1.8 Ma. Ages of palingenic zircon revealed that the Namurian-Westphalian magmatism assimilated larger amounts of crystalline basement that formed during previous Paleozoic geodynamic phases. The Precambrian inherited ages support the chronostratigraphic structure assumed for the Saxo-Thuringian Zone of the Variscan Orogen. The present results help to improve the chronostratigraphic allocation of the Late Paleozoic volcanic zones in Central Europe. At the same time, the radiometric ages have implications for the interbasinal correlation and for the geodynamic evolution of the Variscan Orogeny. 相似文献
120.