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911.
西方办公活动区位研究始于20世纪20年代,是地理学关于生产性服务业区位研究中相对成熟的重要领域。本文以时间为线索,将办公区位研究的进程划分为萌芽阶段、拓展阶段、系统化阶段和成熟阶段;并归纳了各个阶段的主要研究内容.研究角度及不同流派的办公区位理论的发展。研究发现,西方早期办公活动区位呈现强烈的中心性倾向,进入后工业时代以来,受信息技术的影响,办公活动区位出现了郊区化和非CBD倾向。最后总结了西方办公活动区位研究存在的一些问题,如统计数据的限制、理论体系不成熟、城市内部尺度研究不足及信息技术影响下办公活动区位研究不深入等问题,并展望了未来研究的发展趋势。 相似文献
912.
913.
Liu Yaowei 《中国地震研究》2007,21(1):16-32
This paper presents a review of the development of scientific research and practice of earthquake underground fluid in China during the last 40 years, summaries early constructive research and primary achievements in this field. The science of earthquake underground fluid is closely correlated with earthquake monitoring and prediction, such as innovations in observation techniques and theoretical methods, and analysis of diversified parameters and research into predictive methods. The historical evolution of observation networks for underground fluid indicates that the demand for strong earthquake monitoring and prediction has become the driving force of the construction and development of the observation network. The development of observation techniques represents the trend based on multiform measurement, syntheses, and digitization. The study results of underground fluid theory and precursory mechanisms suggest that the precursory model, numerical simulation and in-door or field experimental research are the main technological approaches promoting innovation. Research results of earthquake forecast methods use physics based forecast techniques and the ideas of combination of usability and scientific advance. It has been proved by forecast practice that studying underground fluid is a very important subject in earthquake prediction on the Chinese mainland. Finally, the primary work and technical criterion on underground fluid are introduced, and some major scientific issues and development trends in different historical stages are summarized. 相似文献
914.
1573年甘肃岷县地震史料考证与发震构造探讨 总被引:1,自引:0,他引:1
通过对1573年甘肃岷县地震的历史资料考证和发震构造的综合研究表明:在1573年岷县地震中遭受破坏最为严重的地区位于如今的岷县县城一带(当时为岷州府所在地)。综合各种资料确定1573年甘肃岷县地震震级为621,极震区烈度为Ⅷ~Ⅸ度,震中位于北纬34.4°,东经104.0°,震中精度为2类,震中位置偏差小于或等于25km。该地区构造上位于东昆仑断裂带和西秦岭北缘断裂带的应变传递和构造转换的中间过渡区,其中的临潭-宕昌断裂带活动特性差异明显,只有部分地段表现出全新世活动特征,地震极震区一带分布有不同程度的滑坡和基岩崩塌等。综合分析认为,临潭-宕昌断裂带的岷县-宕昌段是甘肃岷县1573年621级地震的发震构造。 相似文献
915.
通过对业务部门10多年来从事科研组织管理工作的分析,找出了业务单位开展科研与技术开发的对策与措施,对发挥各级气象业务部门的作用,提高气象预报服务质量,加强人才的培养,开展科研和技术开发工作是十分必要的。 相似文献
916.
A Conceptual Framework for Enhancing the Utility of Rainfall Hazard Forecasts for Agriculture in Marginal Environments 总被引:1,自引:0,他引:1
Muhammad?T.?UsmanEmail author Emma?Archer Peter?Johnston Mark?Tadross 《Natural Hazards》2005,34(1):111-129
Semi-arid and dry sub-humid areas (especially in the tropics) are characterized by high inter-annual and intra-seasonal rainfall variability. Agriculture, which employs the bulk of the rapidly increasing populations, is largely rain-fed, low-input based and highly resource dependent. Recent spates of drought have, therefore, exacerbated the now-too-familiar specter of famine and starvation in these areas with glaring examples being the recurring episodes in sub-Saharan Africa since the great Sahel drought of 1969–1973. A great need for accurate and timely hazard forecast products in aid of agriculture thus exists.Several schemes are currently employed by various agencies around the globe in this direction. There does remain, however, a gap between product provision and user expectations. This paper examines this gap suggesting a five-point framework within which it can be addressed as an action agenda for the climate science community. The paper posits that changes are possible to existing methodologies (related to three of these points), which, within the context of current science, can greatly enhance the utility of forecast products for agriculture in marginal areas. The remaining two points have, however, been identified as requiring additional applied research and necessary pointers for addressing these issues are provided. First is the need for appropriate impact-related indicators for intra-seasonal and interannual rainfall variability that are easy to compute, amenable to forecasting and follow closely the experiences of farmers in marginal areas. The second is a consideration of appropriate forecast information formatting and communication medium that guarantee effective feedback between forecast producers and users. Specific examples of the status quo and of work currently underway are cited from southern Africa – a region currently attracting international attention as a result of recent droughts and the threat of famine. 相似文献
917.
西江下游高要水文站洪水预报方法的改进研究 总被引:3,自引:0,他引:3
西江下游河床逐年下切,使高要水文站洪水预报方案的预报误差增大。本文对有关情况进行了分析,并对如何改进高要水文站洪水预报方法进行了改进研究,取得了比较满意的成果。 相似文献
918.
勘查地球化学主要新进展与今后的重要发展领域 总被引:2,自引:2,他引:2
对国内外勘查地球化学一些最新进展进行了综述,认为矿体-成矿系列地球化学异常模式、矿区化探和隐伏矿体定位预测依然是今后的重要领域.同时提出急需建立新的生态环境地球化学理论体系,认为固体矿山受损生态系统的地球化学恢复前景广阔,值得重视的地方病生态环境地球化学预防-预警体系仍需加强.需要开拓研究的新领域有:污染土壤和水体植物地球化学修复理论和新技术、特殊地质环境与综合生态农林业开发的应用地球化学;国外特殊景观地球化学勘查新方法试验和应用研究. 相似文献
919.
920.
Rolf Sternberg 《GeoJournal》2000,50(1):25-36
This article presents an evaluation of the current status of economic geography in general and German economic geography in particular with respect to research topics. A comparison with Anglo-American economic geography, more specifically, its actual research fields are also undertaken on the basis of a bibliometrical analysis of German and international journals dedicated to economic geography. On the basis of this analysis suggested actions are formulated, which could contribute to improved performance of research in German economic geography. 相似文献