排序方式： 共有11条查询结果，搜索用时 31 毫秒
1.
A. B. Pushkarev D. C. Gabuzda Yu. N. Vetukhnovskaya V. E. Yakimov 《Monthly notices of the Royal Astronomical Society》2005,356(3):859-871
We present the results of multifrequency (15 + 8 + 5 GHz) polarization Very Long Baseline Array (VLBA) observations of the three BL Lacertae objects 0745+241, 1418+546 and 1652+398 together with 5-GHz VLBI Space Observatory Programme (VSOP) observations of 1418+546 and 1.6- and 5-GHz VSOP observations of the blazar 1055+018. The jets of all these sources have polarization structure transverse to the jet axis, with the polarization E vectors aligned with the jet along the jet spine and 'sheaths' of orthogonal E vectors at one or both edges of the jet. The presence of polarization aligned with the jet near the 'spine' may indicate that the jets are associated with helical B fields that propogate outward with the jet flow; the presence of orthogonal polarization near the edges of the jet may likewise be a consequence of a helical jet B field, or may be owing to an interaction with the ambient medium on parsec scales. We have tentatively detected interknot polarization in 1055+018 with E aligned with the local jet direction, consistent with the possibility that the jet of this source is associated with a helical B field. 相似文献
2.
Valitov M. G. Shakirov R. B. Lee N. S. Legkodimov A. A. Yakimov T. S. Ponomareva A. L. Kalinchuk V. V. Bovsun M. A. Bulanov V. A. Proshkina Z. N. Syrbu N. S. Korskov I. V. Kalgin V. Yu. Baldanova K. O. Okulov A. K. Makseev D. S. 《Oceanology》2022,62(1):139-141
Oceanology - The paper presents brief results of comprehensive studies of the water area of the Tatar Strait and Sea of Japan obtained on cruise 61 of the R/V “Akademik Oparin” in... 相似文献
3.
4.
The results of 5 and 15 GHz polarization observations of the six blazars 1222+216, 1406−076, 1606+106, 1611+343, 17415-038,
and 2022−077 obtained on the American Very Long Baseline Array are presented. The degrees of polarization in the cores and
jets of these six gamma-ray quasars do not differ from those for other blazars. 相似文献
5.
V.P. EdgcombW. Orsi H.-W. BreinerA. Stock S. FilkerM.M. Yakimov T. Stoeck 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(10):1040-1048
The combination of nearly saturated salt concentration and corresponding high density, high hydrostatic pressure, absence of light, anoxia, and a sharp chemocline make the deep hypersaline anoxic basins in the Eastern Mediterranean Sea some of the most polyextreme habitats on Earth. Using kinetoplastid-specific primers, we detected kinetoplastid flagellates in some of the harshest deep-sea environments known to date, including some whose small subunit ribosomal RNA gene sequences are not closely related to cultured representatives. Kinetoplastids, including presumably novel representatives appear to be specialists of halocline environments in the Eastern Mediterranean, and to comprise a significant fraction of the protist communities in the brines and haloclines of several basins. Fluorescent in situ hybridization data indicate a novel ‘unidentified’ sequence clade of kinetoplastids related to bodonids represents as much as 10% of the total protist community in the Discovery Basin halocline. Different kinetoplastid groups are unevenly represented in the different basins and habitats we sampled, which we discuss as a result of environmental selection. 相似文献
6.
Darcian flow under/through a leaky cutoff wall: Terzaghi–Anderson's seepage problem revisited 
下载免费PDF全文
下载免费PDF全文 An analytical solution is obtained for 2‐D steady Darcian flow under and through a cutoff wall partially obstructing a homogeneous isotropic foundation of a dam. The wall is leaky; that is, flow across it depends on the ratio of hydraulic conductivity of the wall and the wall thickness that results in the third‐type (Robin) boundary condition along the wall, as compared with the Terzaghi problem for an impermeable wall. The Laplace equation for the hydraulic head is meshlessly solved in a non‐standard flow tube. A Fredholm equation of the second kind is obtained for the intensity of leakage across the wall. The equation is tackled numerically, by adjusted successive iterations. Flow characteristics (total Darcian discharge and its components through the wall and the window between the wall top and horizontal bedrock, stream function, head distribution, and Darcian velocity along the wall and tailwater bed) are obtained for various conductivity ratios, head drops across the structure, thicknesses of the foundation, and the degree of its blockage by the wall. Comparisons with the Terzaghi limit of an impermeable wall show that for common wall materials and thicknesses, the leakage may constitute tens of percent of the discharge under the dam. The through‐flow hydraulic gradients on a vertical wall face (Robin's boundary condition) as well as the exit gradients along a horizontal tailwater boundary (Dirichlet's boundary condition) acting for decades have deleterious impacts on dam stability because of potential heaving, piping, and mechanical–chemical suffusion. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
7.
Ponomarev E. I. Litvintsev K. Yu. Shvetsov E. G. Finnikov K. A. Yakimov N. D. 《Izvestiya Atmospheric and Oceanic Physics》2019,55(8):884-892
Izvestiya, Atmospheric and Oceanic Physics - In this work, an improved approach of the pixel-based analysis of the Terra/MODIS imagery is proposed. The approach allows us to improve the accuracy in... 相似文献
8.
The article gives the analysis of the impact of artesian mineralized water flowing from old prospecting wells on water catchment landscapes of river valleys and small watercourses. The processes related to the variation in ion composition of water and chemical composition of bottom sediments of small watercourses under the impact of the technogenic halogenesis are discussed. 相似文献
9.
Travel time of marked fluid particles along arbitrary streamlines in arbitrary porous streamtubes is estimated from below based on the Cauchy–Bunyakovskii (Schwartz) and Jensen inequalities. In homogeneous media the estimate is strict and expressed through the length of the streamline, hydraulic conductivity, porosity and the head fall. The minimum is attained at streamlines of unidirectional flow. The bounds for heterogeneous soils, non-Darcian flows and unsaturated media are also written. If such bounds are attained the corresponding trajectories become brachistochrones. For example, in a two-layered aquifer and seepage perpendicular to the layers there is a unique conductivity–porosity ratio which makes a broken streamline brachistocronic. Similarly, if conductivities of two layers are fixed there is a unique incident angle between flow in one medium and the interface which makes a refracted streamline brachistocronic. 相似文献
10.
A. B. Pushkarev D. C. Gabuzda Yu. N. Vetukhnovskaya V. E. Yakimov 《Astronomy Reports》2005,49(1):5-12
Multi-frequency (5, 8, 15 GHz) total intensity and polarization VLBA images of three sources from a complete sample of BL Lac objects (0745+241, 1418+546, and 1652+398) are presented together with global VLBI images of the quasar 1055+018 at 1.6 and 5 GHz. These images show signs of a spiral magnetic field in the central channel of the jet, as well as a region of longitudinal magnetic field in “sheaths” at the jet edges, which may indicate an interaction between the jet and the surrounding medium on spatial scales of several parsecs. 相似文献