喀斯特山区土地利用变化的人类驱动机制研究——以贵州省为例

根据土地利用和相关的社会经济状况及其变化特征分析,提出了表征县域土地利用变化及其人类驱动因素的指标,分析了二者的联系以探讨人类驱动因素对土地利用变化的驱动机制,指出了人类驱动因素在解释土地利用变化过程中的贡献,为协调喀斯特地区土地资源和人类活动的关系提供依据,为进一步进行土地利用/土地覆盖变化研究积累方法和经验。     

基于结构特征的地图上带晕线多边形的识别

在建立GIS的过程中,从现有的各种比例尺的地形图上获取地理信息是必不可少的工作。带晕线多边形是基本比例尺地形图上最主要的地物要素类别之一,文中在地图二值图像的基础上,根据带晕线多边形的结构特征,利用一系列图像变换技术,首次成功地实现了带晕线多边形的自动识别与提取。提出并实现了用于带晕线类多边形影像分割的4方向RLS变换方法,详细讨论了收缩变换、扩张变换、细化、开图形删除和带晕线类多边形的识别等算法。实验表明,利用文中所述方法进行带晕线多边形识别与提取的正确率可达96%左右。     

储集层构造裂缝定量预测方法研究

选用裂缝体积密度作为构造裂缝定量化参数,对基于钻井岩心的裂缝体积密度的计算方法作了改进。统计分析得出,破裂试件裂缝体积密度与试件破裂应变能密度的关系受试件所受的围压变化及试件物性的控制,钻井岩心构造裂缝体积密度与数值模拟应变能密度的关系同试件研究结果有可比之处。在上述研究基础上,建立了利用钻井岩心裂缝参数和数值模拟应变能密度来定量预测碳酸盐岩储层构造裂缝体积密度的方法,并已应用于油田生     

Black holes and rotation

In this article, we first consider briefly the basic properties of the non-rotating Schwarzschild black hole and the rotating Kerr black hole Rotational effects are then described in static and stationary spacetimes with arial symmetry by studying inertial forces, gyroscopic precession and gravi-electromagnetism. The results are applied to the black hole spacetimes.     

Dragged surge motion of tension leg platforms and strained elastic tethers

This paper presents an analytical solution for the dynamic behavior of both the platform and tethers in the tension leg platform system when the platform system is subjected to the wave-induced surge motion and the flow-induced drag motion. Along with the analysis the coupling problem of a two dimensional tension leg platform interacting with a monochromatic linear wave train in an inviscid and incompressible fluid is being considered. The scattering problem and radiation problem are first solved independently and then combined together to resolve for all unknowns. The dynamic behavior of the platform and tethers was further solved based on these solutions. The material property and the dimensional effect for the tether incorporated in the tension leg platform system are both taken into account in the analytical analysis. Corresponding to the variation of material properties and tether dimensions, it was found that the dynamic behavior of both the tether of tension leg platform and the platform itself is closely related to the material property and the dimension of the tether.     

航磁数据多重分形研究及应用

利用航磁异常场的自仿射分形特征,计算出其分维值,把分维值转化成图形,进而分析其所反映的深层次构造特征。最后对分维值进行了拟合分析     

Two complimentary and integrated land uses of the western High Atlas Mountains, Morocco: the potential for sustainable rural livelihoods

This paper examines the status of traditional agriculture in two areas of Azilal province in the Atlas Mountains, seeking to identify what is needed to counter any breakdown in livelihood strategies and improve the quality of life enjoyed by the farmers. Irrigated terrace agriculture is an important part of livelihood strategies in the areas studied and has the potential to be more productive and sustainable. In some areas it is reported to be endangered by socioeconomic changes and highland land degradation caused by excessive shifting cultivation, sheep and goat grazing, and charcoal production. Field visits made during summer 1998 to establish the condition of irrigated terrace and runoff agriculture and the factors affecting it showed that in at least one of the villages supportive social capital has ensured that challenges are being met and beneficial innovations are being made. Considerable variation in success was evident from community to community, with some farmers maintaining adequate lifestyles and innovating, while in other communities prospects are less promising. The effects of structural adjustment have clearly been felt and may also have triggered some of the highland degradation and difficulties, which clearly threaten some irrigated terrace agriculture and other livelihood practices.     

On the structural test of 1.5-ton test WIG craft

This paper deals with the static structural test of 1.5-ton test WIG (Wing-In-Ground effect) craft designed and built to verify its aero/hydro-dynamic and structural design characteristics prior to the design of full scale 20-passenger WIG craft. The test WIG craft is scaled down from its full scale WIG craft by 1/2 and built using pre-preg carbon/epoxy composites for the majority of structural parts with metallic materials for fittings used at wings to hull connections. To initiate the test, the finite element (FE) models of the test WIG craft are developed and, based on their results, the details of applied load range, strain/deflection gauge types and locations, load application methods and data acquisition system specifications are determined. The test is performed with respect to main wings to hull connection part first and then vertical tail wing to hull connection part and, finally, horizontal tail wing to vertical tail wing/hull connection part. Both the test and FE model results are compared with respect to stresses and deflections and the comparison shows good correlation between them which implies satisfactory design and building of 1.5-ton test WIG craft.     

Petrographic and seismic evidence for the depositional setting of giant turbidite reservoirs and the paleogeographic evolution of Campos Basin,offshore Brazil

The paleogeographic evolution of Campos Basin, a major oil province of Brazil, during the deposition of its giant turbidite reservoirs, was reinterpreted based on the integration of quantitative sandstone petrography and structural analysis of regional 3D seismic data. The major detrital compositional trends indicate that the geodynamic evolution of the continental margin, rather than global eustatic sea-level fluctuations, has exerted the main control on sand supply to the deepwater systems. This control was imposed by the interaction of three geodynamic processes: (i) escarpment retreat of the coastal mountain ridges, (ii) mantle plume-related dynamic uplift and magmatic activity, and (iii) tectonic reactivation of major basement fault-zones. The pattern of distribution of compositional and textural parameters within the turbidite sequences indicated that the sand supply to deepwater was also constrained by high-frequency stratigraphic processes of the climate Milankovitch band. This new approach to the controls on the formation of the sand-rich, deepwater systems in Campos Basin has a key importance for the generation of realistic models for the exploration of new turbidite reservoirs and for the optimized development of producing turbidite oilfields in such a world-class hydrocarbon province. The proposed integrated methodology can help to unravel the controls on the deposition of deepwater sand-rich, deepwater reservoirs in other divergent margin settings.     

海上风力发电机三桩基础波流力的计算

考虑了波浪在水流中的变形,计算了波流共存场中海上风力发电机三柱基础的受力.应用离散涡法,求解了不可压缩粘性流体的水平二维涡量-流函数Navier-Stokes方程,模拟了不同桩位布置对波流场的影响.以及各桩受力和三桩基础总力的随布置方式不同的变化.