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11.
Instability analysis of three-dimensional ocean shear waves 总被引:1,自引:0,他引:1
Qiao Fangli 《海洋学报(英文版)》1996,15(1):1-8
Instabilityanalysisofthree-dimensionaloceanshearwaves¥QiaoFangli(ReceivedNovember6,1995,acceptedNovember30.1995)Abstract:Base... 相似文献
12.
In the Strait of Messina (Sicily, Central Mediterranean Sea) strong tidal currents, very irregular hydrological regime and related solid load, and local seismic activity cause sediment instability; this area represents therefore a case‐study of a naturally disturbed soft‐bottom environment. In this paper, mollusc and polychaete assemblages of the northern part of the Strait were described. Composition, community structure, eco‐ethological features, trophic guilds and sediment‐type relationships were studied in 64 stations sampled located between 3.5 and 50 m depth in October 1992 by means of a Van Veen grab. A total of 131 species (65 molluscs and 66 polychaetes) were identified. A dense population of the tubicolous polychaete Ditrupa arietina was recognized, together with the occurrence of other species tied to a high sedimentation rate, such as Corbula gibba and Tellina distorta, as well as widespread, mud‐tolerant species (e.g.Chone spp., Hyalinoecia tubicola). Diversity (H′) showed a peak at intermediate depths (10/20 m) and a clear decrease beyond this depth, corresponding to the Ditrupa core population. Multivariate comparison between sediment features and community composition throughout the bathymetric gradient showed a narrow ecocline between two environments subjected to opposite hydrodynamic constraints. In the shallower zone, a wide typology of trophic‐ethological guilds was related to community patchiness, in contrast to a greater functional uniformity of the deeper assemblage, dominated by sessile, semi‐infaunal suspension feeders. A possible role played by a phase of increased rainfall to increase bottom instability, locally emphasized by a previous human activity, is also discussed. 相似文献
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用一种新方法研究了三对角方程组及对称三对角方程组计算解的最佳向后扰动分析。由于这两类方程组的系数矩阵具有特殊结构 ,因而本文结果不能从已有结果直接导出。所用方法亦可用于研究 KKT及 SQD等结构线性系统的最佳向后扰动分析。 相似文献
15.
We have developed an analytical treatment for the wave-induced response of a seabed with inhomogeneous permeability, by employing the boundary layer approximation. By assuming an exponential function for vertically distributed permeability, the inhomogeneous consolidation equation was formulated as Bessel's differential equation. Subsequently, we proposed some representative quantities for examining the effects of inhomogeneity of permeability. The main effects of inhomogeneity are that the boundary layer becomes thinner and the phase delay in the direction of depth becomes larger as the inhomogeneity becomes significant. In addition, it was shown that the boundary layer is properly evaluated by using the averaged permeability. 相似文献
16.
梅世蓉 《地震学报(英文版)》1995,(3)
Onthephysicalmodelofearthquakeprecursorfieldsandthemechanismofprecursors'timespacedistribution──originandevidencesof thestron... 相似文献
17.
Aimed at the initial value problem of the particular second-order ordinary differential equations,y
=f(x, y), the symmetric methods (Quinlan and Tremaine, 1990) and our methods (Xu and Zhang, 1994) have been compared in detail by integrating the artificial earth satellite orbits in this paper. In the end, we point out clearly that the integral accuracy of numerical integration of the satellite orbits by applying our methods is obviously higher than that by applying the same order formula of the symmetric methods when the integration time-interval is not greater than 12000 periods. 相似文献
18.
Periodic orbits in the Stormer problem are studied using the symmetry lines of the Poincaré map introduced by De Vogelaere. Many known facts are explained by mean of these lines. The dynamics of four special symmetry lines when the Stormer parameter 1 changes is presented, and we obtain a clear global view of the structure of the simple periodic orbits and their bifurcations, including the asymmetrical ones. New asymmetrical multiple periodic orbits are obtained. 相似文献
19.
单一滑面边坡的非稳定蠕变模型分析 总被引:3,自引:0,他引:3
对单一滑面边坡的非稳定蠕变分析是边坡稳定性研究的基础。文中对岩质边坡单一滑面的流变变形机制进行了分析,提出了一种能较好反映这一变形机制的非稳定蠕变模型。特别是描述单一滑面边坡的非稳定蠕变破坏阶段,并对其稳定性进行了讨论。结合一些工程实例进行了对比验证,为滑坡灾害的预测和防治提供依据。 相似文献
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