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Two scales of levee confinement are commonly recognised from submarine channel-levee systems on the seafloor and in the subsurface. Large-scale external levees bound the entire system whilst smaller-scale internal levees bound individual thalweg channels within the channel-belt. Although thin beds are commonly identified in core and well logs, their origin, and consequently their stratigraphic significance is currently poorly understood. This knowledge gap stems, in part, from the lack of unambiguously identified outcrop analogues of channel-levees, and in particular the lack of identifiable internal and external levees. Here we report from two exhumed channel-levee systems where both scales of confinement can be recognised: the Rosario Fm. of Baja California, and the Fort Brown Fm. of South Africa. A suite of characteristic sedimentary features are recognised from internal and external levees respectively: internal levees are characterised by structures indicative of complexity in the waxing-waning style of overspill, interactions with topography and flow magnitude variability; in contrast, external levees are characterised by structures indicative of simple surge-like waning flows, relatively uniform flow directions, laterally extensive beds, and a lack of erosive events. Using these observations, together with published literature, we propose a simple nomenclatural scheme for levee sub-environments, and criteria to differentiate between levee sub-environments in core or outcrop. 相似文献
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SVOM数据档案库软件原型系统的设计与实现 总被引：1，自引：0，他引：1
作为中法天文卫星(Space multi-band Variable Object Monitor,SVOM)中方科学中心的重要组成部分,中法天文卫星数据档案库承担了中方科学数据产品本地存储和管理的任务,提供统一的数据产品管理平台,实现中法天文卫星科学数据产品的归档、检索、检出、维护与管理等功能。作为中法天文卫星科学中心预研的一部分,对中法天文卫星数据档案库原型系统进行了需求分析、系统设计,实现能够运行的原型系统,以演示中法天文卫星数据档案库的基本功能和工作流程,验证设计方案的可行性。档案库原型系统具有开放性和低耦合的特点,能够适应中法天文卫星中方数据产品结构的不断变化,在项目早期即可投入试用并不断完善,满足中法天文卫星的任务需求。 相似文献
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本文通过对于上海浦江沃尔玛广场设计过程的概念探讨,试图廓清在特定城市区域,通过关键建筑的建设,达到丰富城市空间类型,改善城市空间品质的目的,也在设计整体实践中,思考当下特殊时期,新商业建筑的设计方法。 相似文献
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Michael F. Jischa 《洁净——土壤、空气、水》2008,36(3):255-263
Central elements of the challenges of the future are the population, supply and disposal trap, the question of how the increasing world population will be supplied with long‐lasting and effective sources of energy, raw materials and food? How do we deal with the problems of greenhouse effect, ozone hole, forest dieback, ground erosion, desertification and other environmental threats? Driven by the dynamics of the technical progress the world is in the midst of experiencing the transition from an industrial to an information society. The process of globalization is intrinsically tied to the information society and plays a vital role in the path to a new, digital development of the world. Therefore, new challenges have been added to the traditional ecological challenges at the beginning of the 21st century, which the world community must react swiftly to. 相似文献
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地理信息公共服务平台的用户分类及服务分类 总被引：2，自引：1，他引：1
地理信息技术的发展经历了集中式、模块化、组件化的过程,目前正向地理信息的Web服务方向发展。传统的集中式地理信息系统中,功能的分类决定了用户的分类;而在地理信息服务的架构中,用户的分类导致服务的分类及其与用户分类的映射。本文从地理信息服务的架构出发,分析并提出了面向服务的地理信息公共服务的用户群分类与对应的服务分类,为地理信息公共服务平台的构建和地理信息服务资源的有效组织和整合提供理论依据。 相似文献
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新近发展的图形处理器（GPU，Graphic Processing Unit）通用计算技术，现已日趋实用成型，并获得诸多应用领域的广泛关注.对油气勘探专项资料处理技术的运用而言，概因GPU与中央处理器（CPU）的计算性能的甚大差异，致使GPU这一通用计算技术在石油工业中的应用研究正在有效开展.本文仅借助于油气勘探中广泛使用的叠前时间偏移，旨在于扼要阐明其基于GPU应用的有效性；文中还提出一种利用GPU实现地震叠前时间偏移的软件构件方法，并针对非对称走时叠前时间偏移所拓展的应用软件提供一种具体实现架构.与以往用个人计算机（PC，Personal Computer）或者PC集群所用的叠前时间偏移相比，本文方法可甚大地提高计算效率，从而在石油物探资料处理中可显著地节约计算成本和维护费用.文中实际例证也表明，基于GPU进行高性能并行计算，当是适应目前石油工业中大规模计算需求的一个重要发展途径. 相似文献
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Peter Adey 《Geoforum》2008,39(1):438-451
Drawing on work surrounding the theorisation of concepts such as mobility, affect and emotion, the paper argues that their control is now being intertwined in places like airports which are employing a number of techniques that engineer affects. Airport affect is enacted, in one way, by planning and designing the situational affective context one inhabits - throwing up structures of ethological possibility that shape capacities for the corporeal body to move and be moved. It is shown that the engineering of airport affect is premised upon a wider discursive framework of calculation and indeterminacy, and that selective techniques summon a number of different modalities of control. The paper concludes with a series of implications for the understanding of power, and the study of mobility, emotion and affect. 相似文献
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