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111.
V. A. Marinov S. V. Meledina O. S. Dzyuba O. S. Urman O. V. Yazikova V. A. Luchinina A. G. Zamirailova A. N. Fomin 《Stratigraphy and Geological Correlation》2006,14(4):418-432
Paleontological study of Upper Jurassic and Lower Cretaceous sediments recovered by boreholes in the Agan-Vakh and Nadym-Vengapur interfluves clarified environments of their deposition. As is shown, influx of siliciclastic material to central areas of the West Siberian sea basin varied through time. Taxonomic composition and ecological structure of nektonic and benthic fossil assemblages are analyzed and considered in terms of environmental factors such as hydrodynamics, aeration, temperature, and salinity of seawater. 相似文献
112.
113.
Basic to the study of urban growth is information on population and land use changes. These basic data are generally lacking in Nigeria. This paper examines and assesses the growth of urban land use of Lagos (the Federal Capital of Nigeria) through a systematic utilization of sequential serial photographs (taken in 1962 at a scale of 1:40,000, and in 1974, at a scale of 1:20,000) and computer techniques. The land use data resulting are then used in evaluating the population growth of Lagos. The resulting population estimate is then compared with the available population data. The study concludes by recommending the use of remote sensing, especially aerial photography for the acquisition of basic urban data not only in Nigeria but also in other developing countries lacking in such data. 相似文献
114.
M. A. Pogodin N. G. Beskrovnaya G. G. Valyavin I. S. Guseva S. E. Pavlovskiy N. Rusomarov O. V. Ezhkova 《Bulletin of the Crimean Astrophysical Observatory》2013,109(1):23-26
We present first results of the photometric and spectroscopic investigation of the B1/B2 Herbig star HD52721 performed in 2009–2010 at three observatories: Mountain Astronomical Station (Kislovodsk)—photometry, CrAO (Crimea, Ukraine)—spectroscopy, Observatory San Pedro Martyr (Ensenada, Mexico)—high-resolution echelle-spectroscopy. We have also used photometric data from the ASAS survey for 2003–2009. Our analysis has shown that a) the object is a close binary system with the orbital period of 1.610 days composed of two components of similar spectral type (B1–B2); b) the system is surrounded by the common disk-like envelope containing azimuthal inhomogeneity rotating with the orbital period of the system. We present preliminary estimates of the system parameters and discuss its possible nature. 相似文献
115.
Pulkovo astrometric observations began in the 1840s using the Repsold transit instrument in the prime vertical and Ertel vertical
circle. The first observers on these instruments were W.I. Struve, 1840–1856, and Kh.I. Peters, 1842–1849. In the present
work, we collected and analyzed different series of latitude variations from observations made by M.O. Nuren, B. Wanach, A.A.
Ivanov, I.N. Bonsdorf, and A.Ya. Orlov. In addition, results are given of investigations of a specific behavior of the Chandler
polar motion in this interval, obtained by C. Chandler, Ivanov, Kh. Kimura, Orlov, and N. Sekiguchi. The aim of this paper
is to search for and analyze the earliest series of Pulkovo latitudes, in order to evaluate the possibility of their use to
study the motion of the pole at the maximum available range of observations. Different methods were used to isolate and analyze
the sum of Chandler and annual latitude variations. The annex provides a series of Pulkovo latitude variations for 1840–1848,
which may be used to extend latitude variation back to 1840. 相似文献
116.
117.
We show that a class of solutions for a vacuum cylindrically symmetric gravitational field with nonvanishing cosmological constant reduce to the welknown Levi-Civita metric close to the axis. All the circular geodesics in this generalized vacuum are time like, null or space like depending on the relative magnitudes of the two parameters appearing in the solutions.For other particles moving inZ=constant plane there are some cases where the trapping of timelike and null trajectories occur, while in other cases some of the particles may orbit round the axis in a fixed zone bounded by two limiting radii. 相似文献
118.
G. M. Karataeva V. A. Yakovleva V. A. Hagen-Thorn O. V. Mikolaichuk 《Astronomy Letters》2001,27(2):74-80
We analyze our BVR c photometry for UGC 5600, a candidate polar ring galaxy, obtained with the 6-m telescope. We have confirmed the existence of an inner polar ring and show that the outer ring-shaped structure represents spiral arms; i.e., UGC 5600 belongs to the rare class of gas-rich spiral galaxies with inner polar rings. 相似文献
119.
按溃变理论[1]的不连续或非均匀信息不仅可以预测天气系统的移动性变化和转折性变化,也可以预测降水等天气现象。并已被多次历史例案和应用实践所验证。为了便于投入业务运用,我们利用数据库系统,实现了体现资料信息非均匀和不连续的广义参数在微机、填图机上的自动化处理,完成了收报、计算和填图分析的自动化。本方法体现了预报工具的改革也充分地利用了现有的资料资源 相似文献
120.