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11.
Valeri Grebenets 《冰川冻土》2004,26(Z1):296-300
In last years, the problem of building s stability in northern areas has become aggravating. The main reasons mass deformations areas follows: 1) mistakes during research, planning, construction and operation of objects; 2) negative changes in frozen ground, bound with reduction of footing s bearing capacity under technogenic impact; 3) premature wear of material of underground constructions under influence of natural and technogenic factors. 相似文献
12.
Gennady Andrienko Natalia Andrienko Valeri Gitis 《ISPRS Journal of Photogrammetry and Remote Sensing》2003,57(5-6):380
This article considers two types of tools used for the analysis of spatial data: computational tools for grid data and visualization-based interactive exploratory techniques. The main purpose is to demonstrate that computational and visual techniques are complementary, and their combined use in data analysis may produce a synergistic effect. To this end, we describe two example scenarios of data analysis in the evaluation of potential damage from earthquakes and in analysis of forest resources. The analyses were performed with the use of CommonGIS, featuring the availability of powerful geocomputational tools and interactive visualization-related facilities that can be efficiently used in combination in a desktop environment or via the World Wide Web. 相似文献
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This paper discusses some previous, and presents some new experimental results on wave transmission oversubmerged breakwaters. The objective of this study is to evaluate wave transmission coefficient and develop two-dimensional (2D) model as an improvement to the existing wave transmission coefficient models. Factors which affect wave transmission over submerged breakwaters are discussed through series of laboratory experiments. Basic recommendations for evaluation and design of submerged rubble-monud breakwaters are presented.From the test results, calculation formula of wave transmission coefficient is proposed. 相似文献
14.
Accurate two-colour photometry and proper motions of 7096 young X-ray stars in the ROSAT All-Sky Survey Bright Star Catalogue, version 1RXS, are extracted from the Tycho-2 Catalogue. The sample is dominated by red main-sequence and possibly pre-main-sequence stars. On a global proper motion convergence map, two features are very prominent: the nearby section of the Gould Belt and the Hyades convergent point. The appearance of the Gould Belt feature with its peak at ( l =2443, b =−126) is quite similar to that of Hipparcos OB stars. When only stars with proper motions drawing close to that point are selected, strong concentrations of stars in the direction of the Sco–Cen complex are found. Another concentration, not corresponding to any known OB association, is detected between the position of the Lower Centaurus Crux and Vela OB2 associations. It is a new young moving group located in Carina and Vela, and a near extension of the Sco–Cen complex. Contrary to the classical Gould Belt OB associations, the Carina–Vela moving group has a considerable geometric depth, the closest members being as near as 30 pc from the Sun. IC 2391, one of the youngest and closest open clusters on the sky, is a part of the Carina–Vela moving group. The Carina–Vela moving group does not link the Sco–Cen complex with the Vela OB associations, because the latter is much more distant than the outer limit of the sample. It is more likely that the young late-type population of the Scorpio–Centaurus–Carina moving group stretches towards the Sun and possibly beyond it. 相似文献
15.
A 6 hour patrol search in the region of the Pleiades aggregate with the 40″ and 21″ Schmidt telescopes at the Byurakan Astrophysical
Observatory provided simultaneous data in two colors (Pg and U) on a flare of the star FSP 377=HII 2411 in the Hyades cluster.
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Translated from Astrofizika, Vol. 49, No. 2, pp. 299–302 (May 2006). 相似文献
16.
V. V. Hambaryan L. V. Mirzoyan R. Wichmann J. Krautter R. Neuhäuser 《Astrophysics》1997,40(4):354-362
The X-ray data of a sample of 104 flare stars (FSs) in the Pleiades cluster region obtained by Stauffer et al. [1] on the
basis of deep ROSAT PSPC observations are analyzed. If we divide the X-ray emission detected in late-type stars of the Pleiades
cluster into FSs and non-FSs, we find that X-ray luminosities of stars of both groups can be considered as coming from the
same parent population. Moreover, in order to classify stars in a sample of 23 late-type Pleiades stars of unknown nature
discriminant analysis in a four-dimensional parameter space (log (Lx, log (Lx/Lbol), and ROSAT hardness ratios HR1 and HR2) has been used. It can be shown that the majority of these stars (16) are very likely
FSs rather than non-FSs.
Published in Astrofizika, Vol. 40, No. 4, pp. 545–557, October-December, 1997. 相似文献
17.
Alan Marscher Svetlana G. Jorstad Valeri M. Larionov Margo F. Aller Anne Lähteenmäki 《Journal of Astrophysics and Astronomy》2011,32(1-2):233-237
We are leading a comprehensive multi-waveband monitoring program of 34 γ-ray bright blazars designed to locate the emission regions of blazars from radio to γ-ray frequencies. The ‘maps’ are anchored by sequences of images in both total and polarized intensity obtained with the VLBA at an angular resolution of ～0.1 milliarcseconds. The time-variable linear polarization at radio to optical wavelengths and radio to γ-ray light curves allow us to specify the locations of flares relative to bright stationary features seen in the images and to infer the geometry of the magnetic field in different regions of the jet. Our data reveal that some flares occur simultaneously at different wavebands and others are only seen at some of the frequencies. The flares are often triggered by a superluminal knot passing through the stationary ‘core’ on the VLBA images. Other flares occur upstream or even parsecs downstream of the core. 相似文献
18.
L. V. Mirzoyan V. V. Hambaryan A. A. Akopian A. V. Poghosyan G. N. Salukvadze 《Astrophysics》1999,42(3):247-254
The analysis of the proper motions of bright members of the Per OB2 association on the basis of Hipparcos high-accuracy astromethc
observations is presented. The existence of two different subgroups of OB-stars in the Per OB2 association that are in the
state of expansion is considered. The expansion ages are calculated as 1.3 and 1.9×106 years. The membership of the observed OB-stars to these subgroups is considered.
Deceased.
Published in Astrofizika, Vol. 42, No. 3, pp. 333–340, July–September, 1999. 相似文献
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