绳索取心钻进在祁连下沟矿区斜孔中的应用     

张宁禹  张庆海 《青海国土经略》1993,(2)

小口径金刚石钻头绳索取心钻进,在青海祁连下沟矿区取得明显的质量效应。该工艺及设备投入后获得的岩心采取率达95.93%,矿心采取率98.87%,优质孔率100%,孔斜超差率低,占月效率平均达464.48m。结合使用:可退式套管、钻杆两用卡管器”专用设备后更收益匪浅。文章对此给予了总结分析和比较。  相似文献   

Variability of the central region in active galactic nuclei   总被引：3，自引：0，他引：3  

F. H. Wallinder  S. Kato  M. A. Abramowicz 《Astronomy and Astrophysics Review》1992,4(2):79-122

Summary We review implications of the observed optical and X-ray variability (periodicities and light-curves), relevant for the understanding of physical conditions in the deep interiors of active galactic nuclei. We discuss in detail kinematical, hydrodynamical, thermal and radiative transfer effects which may be responsible for observed variability patterns. We put emphasis on theoretical options which can predict basic accretion parameters, such as the mass of the central black hole, the accretion rate and the inclination angle, in terms of observable quantities. Closed analytical results are given whenever available.  相似文献   

On the formation and evolution of black hole binaries   总被引：1，自引：0，他引：1  

Ph. Podsiadlowski  S. Rappaport  Z. Han 《Monthly notices of the Royal Astronomical Society》2003,341(2):385-404

We present the results of a systematic study of the formation and evolution of binaries containing black holes and normal-star companions with a wide range of masses. We first reexamine the standard formation scenario for close black hole binaries, where the progenitor system, a binary with at least one massive component, experienced a common-envelope phase and where the spiral-in of the companion in the envelope of the massive star caused the ejection of the envelope. We estimate the formation rates for different companion masses and different assumptions about the common-envelope structure and other model parameters. We find that black hole binaries with intermediate- and high-mass secondaries can form for a wide range of assumptions, while black hole binaries with low-mass secondaries can only form with apparently unrealistic assumptions (in agreement with previous studies).
We then present detailed binary evolution sequences for black hole binaries with secondaries of 2 to 17 M_⊙ and demonstrate that in these systems the black hole can accrete appreciably even if accretion is Eddington-limited (up to 7 M_⊙ for an initial black hole mass of 10 M_⊙) and that the black holes can be spun up significantly in the process. We discuss the implications of these calculations for well-studied black hole binaries (in particular GRS 1915+105) and ultraluminous X-ray sources of which GRS 1915+105 appears to represent a typical Galactic counterpart. We also present a detailed evolutionary model for Cygnus X-1, a massive black hole binary, which suggests that at present the system is most likely in a wind mass-transfer phase following an earlier Roche-lobe overflow phase. Finally, we discuss how some of the assumptions in the standard model could be relaxed to allow the formation of low-mass, short-period black hole binaries, which appear to be very abundant in nature.  相似文献   

Line temperatures and elemental abundances in H ii galaxies     

Enrique Pérez-Montero  Angeles I. Díaz 《Monthly notices of the Royal Astronomical Society》2003,346(1):105-118

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Ab initio simulations of accretion disc instability     

V. Teresi  D. Molteni  E. Toscano 《Monthly notices of the Royal Astronomical Society》2004,351(1):297-310

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XMM–Newton RGS spectroscopy of LMC X-3     

M. J. Page  R. Soria  K. Wu  K. O. Mason  F. A. Cordova  W. C. Priedhorsky 《Monthly notices of the Royal Astronomical Society》2003,345(2):639-649

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Chandra High-Resolution Camera observations of the luminous X-ray source in the starburst galaxy M82     

P. Kaaret  A. H. Prestwich  A. Zezas  S. S. Murray  D.-W. Kim  R. E. Kilgard  E. M. Schlegel  M. J. Ward 《Monthly notices of the Royal Astronomical Society》2001,321(2):L29-L32

We analyse Chandra High Resolution Camera observations of the starburst galaxy M82, concentrating on the most luminous X-ray source. We find a position for the source of         (J2000) with a 1 σ radial error of 0.7 arcsec. The accurate X-ray position shows that the luminous source is neither at the dynamical centre of M82 nor coincident with any suggested radio AGN candidate. The source is highly variable between observations, which suggests that it is a compact object and not a supernova or remnant. There is no significant short-term variability within the observations. Dynamical friction and the off-centre position place an upper bound of 10⁵–10⁶ M_⊙ on the mass of the object, depending on its age. The X-ray luminosity suggests a compact object mass of at least 500 M_⊙. Thus the luminous source in M82 may represent a new class of compact object with a mass intermediate between those of stellar-mass black hole candidates and supermassive black holes.  相似文献   

Radio emission as a test of the existence of intermediate-mass black holes in globular clusters and dwarf spheroidal galaxies     

Thomas J. Maccarone 《Monthly notices of the Royal Astronomical Society》2004,351(3):1049-1053

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Surface and sub‐surface Schmidt hammer rebound value variation for a granite outcrop     

Barbora Černá  Zbyněk Engel 《地球表面变化过程与地形》2011,36(2):170-179

This study presents rock strength variations at granite outcrops and in subsurface vertical profiles in the Jizerské hory Mountains, Czech Republic. Schmidt hammer rebound values in subsurface profiles change gradually from the bedrock surface downward. An exponential relation has been observed between the R‐values and depth in rock outcrops to a depth of around 4·5 m. The exponential nature of the curve indicates that rock hardness increases more rapidly with depth in the uppermost 1?m section of the rock profile. A detailed study of rebound values obtained from both intact and polished rock exposures reveal effects of surface grinding on results of the Schmidt hammer method. The range of data collected increases after grinding, allowing more precise discrimination of rock surfaces in respect of age and weathering. The Schmidt hammer method may be used effectively as a relative‐age dating tool for rock surfaces that originated during the Late Pleistocene. It is concluded that this time limitation can be significantly mitigated by surface grinding before measurement. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

汶川8.0级地震前水氡浓度的临界慢化现象研究   总被引：1，自引：0，他引：1       下载免费PDF全文

晏锐  蒋长胜  张浪平 《地球物理学报》2011,54(7):1817-1826

近年来,临界慢化(Critical slowing down)现象在揭示复杂动力系统是否趋于临界性灾变方面展示了重要潜力.本文基于临界慢化的概念,将其用于水氡浓度观测资料的处理,以2008年5月12日汶川8.0级地震前龙门山断裂带破裂段及附近地区水氡浓度观测点资料为例,分别计算了表征临界慢化现象的自相关系数和方差.结果...  相似文献