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871.
Until recently, only fossils of Caradoc to Carboniferous age have been reported from the Northern Greywacke Zone/Eastern Alps. New medium-preserved and diversified acritarch assemblages from the Lower Wildschönau Formation indicate a Lower Ordovician (Tremadoc and Arenig) age. These fossil spectra define a well-constrained time interval for a lower section of the Northern Greywacke Zone for the first time. 相似文献
872.
Infiltration experiments have been performed at three sites along a well-known catena under virgin tropical rain forest using a portable sprinkling infiltrometer. Experimentally determined infiltration curves are presented. Infiltration curves are also simulated on the basis of the Mein-Larson equation. The parameters for this model have been obtained from the infiltration curves (saturated conductivity) and simple soil moisture determinations (fillable porosity). The agreement between experimentally determined and modelled infiltration is reasonable, provided (a) saturated conductivity as derived from the experimental data is corrected, (b) a storage parameter, also derived from the experimental data, is added to the Mein-Larson model, and (c) the decline in soil porosity with depth is either small or occurs abruptly at shallow depth. Comparison of observed infiltration rates with rainfall intensity shows that Horton Overland Flow has to occur naturally at least on the middle and lower section of the catena. Despite the fact that most parameters can be estimated in principle from basic soil data, it remains advisable to obtain sprinkling infiltrometer field measurements, because of soil variability due to dynamic surface conditions, macroporosity, air entrapment, and irregularity of the wetting front. 相似文献
873.
本文作者利用IOS近似模型,计算了星际分子云条件下A型CH3CN-H2含超精细能级的碰撞跃迁速率系数。温度范围是20K-140K。为研究分子云与恒星形成区的物理、化学性质提供了有用的基础分子数据。 相似文献
874.
875.
We obtain the possible ellipsoidal and hyperboloidal equilibrium figures of the light subsystem with internal fluxes of matter of constant vorticity inside a gravitating homogeneous triaxial ellipsoid. We obtain the domains of stability of these equilibrium figures with respect to second-form oscillations.Translated fromAstrofizika, Vol. 38, No. 2, 1995. 相似文献
876.
Abstract Dahmani is a shocked LL6 fragmental breccia. According to the composition of the silicates (olivine Fa30,32.6, orthopyroxene Fs24.5–26.3) and of the metal (a 60% Ni taenite) it is one of the most oxidised known. 相似文献
877.
In this paper we consider the time-dependent diffuse reflection and transmission problems for a homogeneous anisotropically-scattering atmosphere of finite optical depth and solve it by the principle of invariance. Also we consider the time-dependent diffuse reflection and transmission of parallel rays by a slab consisting of two anisotropic homogeneous layers, whose scattering and transmission properties are known. It is shown how to express the time-dependent reflected and transmitted intensities in terms of their components. In a manner similar to that given by Tsujita (1968), we assumed that the upward-directed intensities of radiation at the boundary of the two layers are expressed by the sum of products of some auxiliary functions depending on only one argument. Then, after some analytical manipulations, three groups of systems of simultaneous integral equations governing the auxiliary functions are obtained. 相似文献
878.
The dynamical evolution of meteoroid streams associated with cornets Encke, Halley, Machholz 1986 VIII and asteroid Phaethon is discussed. It is shown that the planetary perturbations can greatly increase the streams thickness and each stream may produce several couples of meteor showers active in different seasons of the year. The theoretical and observed data are in a satisfactory accordance. 相似文献
879.
880.