区域物流中心(城市)空间体系及驱动机理研究   总被引：3，自引：0，他引：3  

李海建  谢五届  曹有挥 《世界地理研究》2005,14(4):35-42

物流中心城市空间体系是指在一定地域范围内以物流枢纽城市为核心,以具有经济优势和物流组织条件的边缘城市为支持而构成的空间有机体。本文以安徽省为例证,建立物流巾心（城市）模糊区间层次（IGJAHP）综合评判模型,测算安徽省17个城市的物流发展水平,评判物流中心（城市）的等级;探讨物流中心（城市）的功能及发展模式;在此基础上,引用“轴-辐（hub—and—spokes）”空间理论,构筑以芜湖-合肥为双核心,以蚌埠、阜阳、安庆等为支持的区域物流中心HS空间格局;最后,从商流中心、交通网络、内外部经济效益以及物流技术等诸方面,探讨物流中心（城市）空间体系演进的驱动机理,以期推动安徽省区域物流的发展。  相似文献   

技术流的动力机制、渠道与模式——以珠江三角洲为例   总被引：9，自引：1，他引：9  

许学强  王欣  阎小培 《地理学报》2002,57(4):489-496

技术流是一个与人流，物流，信息流相并广泛使用的词汇，但学界极度缺乏对技术流概念，机制，渠道以及模式等基本理论的探讨。以珠江三角洲为例，通过城市，交易会，企业三个层次的多案例实主研究，提出了技术流的要领，技术流动力机制－深圳新二元结构，技术流的新型渠道－高交合的复合嵌套平台模式，以及企业间技术流模式与空间模式。  相似文献   

大数据量遥感分类图像的动态矢量化算法     

荣岳成 《测绘学报》2012,41(6):898-903

针对大数据量遥感图像矢量化时间效率低和空间瓶颈问题,采用顶点提取过程中同时进行图斑矢量化的策略,提出一种适应大数据量遥感图像的动态矢量化算法。首先,统计图像中各图斑的顶点个数,将其作为图斑顶点集合能否构成封闭多边形的判定条件;然后,在顶点提取的过程中发现有能够成封闭多边形的图斑顶点集合,立即将其矢量化并释放其所占内存,图斑矢量化时直接将顶点构建成多边形无需生成中间弧段,并即时形成拓扑关系。实验表明,文中算法能快速高效地完成大数据量遥感图像矢量化,速度是ARCGIS（9.2版本）矢量化算法的3~4倍。  相似文献   

Genesis of the Madang Cenozoic sodic alkaline basalt in the eastern margin of the Tibetan Plateau and its continental dynamic implications     

LAI ShaoCong  ZHANG GuoWei  LI YongFei  QIN JiangFeng 《中国科学D辑(英文版)》2007,50(Z2):314-321

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Optical dating of aeolian dynamism on the West African Sahelian margin   总被引：1，自引：0，他引：1  

S. Stokes  R. M. Bailey  N. Fedoroff  K. E. O'Marah 《Geomorphology》2004,59(1-4):281

The Sahelian Margin of West Africa is widely recognised as an area of recent environmental catastrophe and human suffering arising from food shortage and land degradation associated with prolonged drought. The propensity of this region to suffer drought has been related, using environmental data collected during the period of instrumental records, to a combination of low mean annual rainfall levels and a high degree of rainfall variability which relates to sea surface temperature anomalies in the adjacent tropical Atlantic Ocean. Despite the significant environmental and human consequences of such droughts, there is a paucity of long-term environmental data for the West African Sahel. Aeolian dune reactivations in this area are a potentially highly useful environmental archive of past periods of extended drought conditions, which may have resulted in localised or widespread dune reactivation. Here we describe the initial results from an ongoing programme of research, which seeks to develop a detailed record of past dune reactivations in Mali. We find evidence for repeated Holocene dune reactivation events and a significant number of reactivations, which commenced at the time of onset of the last major drought cycle in the early 1970s. We obtain ages as young as 20–30 years for some significant dune units (thickness up to 1 m) and describe the results of experiments which test the performance of our dating exercise. We specifically test for the significance of preheat temperature on single aliquot regeneration (SAR) equivalent dose determinations and recycling ratios; neither are found vary significantly as a function of preheating. Optical dating of sand sized quartz could provide a useful tool for palaeogeographical mapping of ancient and historical dune reactivations in this region and elsewhere.  相似文献