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181.
I discuss the status of the soft X-ray transient model. First, I discuss and then compare with observations the assumption that the geometrically thin disc evaporates into an ADAF. Second, I address the problems created by the recent determinations of the distance to SS Cyg, according to which the disc instability model does not apply to this famous dwarf-nova, thus casting doubt on the application of this model to any system at all. 相似文献
182.
C. R. Kaiser 《Monthly notices of the Royal Astronomical Society》2006,367(3):1083-1094
Flat radio spectra with large brightness temperatures at the core of active galactic nuclei and X-ray binaries are usually interpreted as the partially self-absorbed bases of jet flows emitting synchrotron radiation. Here we extend previous models of jets propagating at large angles to our line of sight to self-consistently include the effects of energy losses of the relativistic electrons due to the synchrotron process itself and the adiabatic expansion of the jet flow. We also take into account energy gains through self-absorption. Two model classes are presented. The ballistic jet flows, with the jet material travelling along straight trajectories, and adiabatic jets. Despite the energy losses, both scenarios can result in flat emission spectra; however, the adiabatic jets require a specific geometry. No re-acceleration process along the jet is needed for the electrons. We apply the models to observational data of the X-ray binary Cygnus X-1. Both models can be made consistent with the observations. The resulting ballistic jet is extremely narrow with a jet opening angle of only 5 arcsec. Its energy transport rate is small compared to the time-averaged jet power and therefore suggests the presence of non-radiating protons in the jet flow. The adiabatic jets require a strong departure from energy equipartition between the magnetic field and the relativistic electrons. These models also imply a jet power of two orders of magnitude higher than the Eddington limiting luminosity of a 10-M⊙ black hole. The models put strong constraints on the physical conditions in the jet flows on scales well below achievable resolution limits. 相似文献
183.
J. Escuder Viruete R. Carbonell M. J. Jurado D. Martí A. Prez-Estaún 《Journal of Structural Geology》2001,23(12)
We use a fracture index distribution method of geostatistical modelling and prediction to characterize quantitatively the fracture system in two-dimensions (2D) in the Mina Ratones area, located in the Albal1; Granitic Pluton (SW Iberian Massif). The fracture index (FI) is a quantitative estimate of the fracture density in discrete domains. To validate the results of geostatistical modeling a detailed structural map of the area was also made on a scale of 1:1000. The resulting grids, expressed as pixel-maps, describe the continuous value of the FI in 2D for the whole Mina Ratones area. Based on the modelled distribution of the FI and their correlation with mapped faults, we distinguish two structural domains in the studied area: elongated bands of fracture zones with high FI values and romboidal blocks located between them with low FI values. The separation between both domains is gradual. Though a threshold value of the FI that separate both structural domains is not clearly defined, the fracture zones generally present FI>1 and the individualized blocks FI<0.50. As a consequence, the obtained grid of the FI permits the quantitative structural classification of the granitic massif in 2D and understanding fault zone architecture in the Mina Ratones area. 相似文献
184.
Location of Tibetan earthquakes──a nonlinear approach by a simplex optimized technique 总被引:1,自引:0,他引:1
Location of Tibetan earthquakes──a nonlinear approach by a simplex optimized technique(赵珠)(丁志峰)(易桂喜/)(王建格)LocationofTibetanea... 相似文献
185.
SBAS监测技术作为微波遥感技术,通过最小二乘或奇异值分解的方法,对多个构成三角网的干涉对进行干涉处理,从而得到某个地区的时问序列形变规律.本文使用SBAS技术对覆盖临沧市2019年2月—2020年7月的30景Sentinel-1A雷达数据进行处理.通过剖面和时问序列分析方法对该区域进行分析,研究其地表沉降成因和规律,... 相似文献
186.
????GM(1,1)?????????????????????????????????????????GM(1,1)?????????????????????????GM(1,1) ??????GM(1,1)??PGM(1,1)?????GM(1,1)????????????б???????????????????????GM(1,1)???????????? 相似文献
187.
处理了聊古一井1981 ~1984 年氦的观测资料,发现在两次较近的地震(1981 年宁晋MS5 .8 和1983 年菏泽MS5 .9) 前,氦都有明显的形态相似的异常变化. 相似文献
188.
介绍了锦屏一级水电站右岸导流洞的工程地质概况及施工期安全监测成果,对围岩及边坡的变形、应力规律及特征进行了深入的分析,分析结果表明,隧道围岩及边坡处于稳定状态。 相似文献
189.
ICP-MS测定地质样品中37个元素的准确度和长期稳定性分析 总被引:8,自引:10,他引:8
对Elan6100DRC型ICP-MS近五年来所测得的国际地质标样BHVO-1(玄武岩)和AGV-1(安山岩)中的37个元素的测定值以及仪器灵敏度的长期漂移情况进行了统计分析(共计146次).结果表明,几年来ICP-MS所测数据的长期稳定性和准确度都较好,除个别元素Li(BHVO-1)、Be(BHVO-1))、Cr(AGV-1)、CS(BHVO-1)和Pb(BHVO-1)的相对误差(与参考值比较)接近或略大于10%外,绝大多数元素的相对误差和相对标准偏差(RSD,测定值之间,n=146)都在5%以内;仪器灵敏度并不是随着时间一直往下漂,有的是往上漂的,也有上下漂的,即使是在同一时间内,有的元素灵敏度往上漂,而有的往下漂.常用的内标法无法较好校正这种漂移,而需要采用内外标相结合的校正方法.不同批次,210个各种地质样品中Rb、Sr、Zr和Nb的XRF和ICP-MS分析结果对比情况表明,绝大多数样品中Rb、Sr、Zr和Nb的ICP-MS和XRF的测定值的相对误差小于10%.以上的分析结果表明,我们实验室所建立的以密闭高温高压消解技术为样品前处理方法,以模拟地壳样品中元素天然丰度比的基体匹配校正标准溶液为外标和以Rh为内标结合外标校正的ICP-MS多元素分析方法具有非常好的准确度和长期稳定性. 相似文献
190.
The Molí del Baró-1 site (north-eastern Iberia) has yielded one of the richest fossil assemblages of the continental upper Maastrichtian from western Europe. It includes abundant plant (charophytes, sporomorphs, angiosperm leaves, seeds and logs), invertebrate (mollusc shells, partial insect exoskeletons and eggs) and vertebrate (teeth, bones, eggshells) fossils. The fossil assemblage is composed of both parautochthonous and allochthonous remains that mostly deposited in a pool formed at the edge of a meandering river. Plant megafossil evidence suggest that at least three angiosperm species (a willow-like dicot, palms and a likely typhacean monocot) formed the plant community growing in this fluvial environment. Tooth remains indicate that crocodylomorphs were diverse (including atoposaurids, ziphosuchians and eusuchians) which together with small theropod dinosaurs likely consumed prey carcasses or scavenged near the depositional setting. Prismatoolithid eggshells also suggest the presence of nearby nesting area of theropods. On the other hand, hadrosauroids apparently dominated phytophagous faunas including lambeosaurines as well as more basal forms. The taxonomic composition of the Molí del Baró-1 site matches the expected for the timespan and environment and represents a relevant locality to know the diversity of the latest Cretaceous terrestrial ecosystems in south western Europe. 相似文献