Architecture of the lower terraces and evolution of the Dordogne River at Bergerac (south‐west France) during the last glacial–interglacial cycle     

PASCAL BERTRAN  MARINE FROUIN  NORBERT MERCIER  FABIEN NAESSENS  FRÉDÉRIC PRODEO  ALAIN QUEFFELEC  COLETTE SIRIEIX  LUCA SITZIA 《第四纪科学杂志》2013,28(6):605-616

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THE HYDROGEOLOGY OF GHANA     

DR. M. ERDÉLYI 《水文科学杂志》2013,58(1):44-52

SUMMARY

Many hydrological systems exhibit long periods of quiescent behaviour, broken only occasionally by short periods of comparatively intense activity. Clear examples arise in stream run-off measurements and in ground water table observations. The number of measurements recorded can then be considerably reduced by reducing the frequency of recording over the quiescent periods. The paper describes an algorithm whereby this reduction is attained in an optimum manner. When recordings can be accepted directly by a computer, the algorithm simply provides a translation programme Whereby the quality of data may be very considerably reduced. Other applications are, however, discussed.

The problems of Optimum representations is first presented, and choices of norm indicated. Using a particular norm, it is shown that the optimum representation is characterised, under certain limiting conditions, by the property that the second moments of the second derivatives are constant over all optimum intervals. This characterisation is used to construct an iterative difference scheme, whereby a certain truncation error is accepted. Sufficient conditions for stability of the scheme are determined and these incorporated into a computer programme. The programme has been tested on a variety of data with satisfactory results. In conclusion, a further development of the method is indicated.  相似文献   

Integration of remote sensing data into hydrological models for reservoir management     

C. LOUMAGNE  M. NORMAND  M. RIFFARD  A. WEISSE  A. QUESNEY  S. LE HÉGARAT-MASCLE 《水文科学杂志》2013,58(1):89-102

Abstract

The purpose of this paper is to present the methodology set up to derive catchment soil moisture from Earth Observation (EO) data using microwave spaceborne Synthetic Aperture Radar (SAR) images from ERS satellites and to study the improvements brought about by an assimilation of this information into hydrological models. The methodology used to derive EO data is based on the appropriate selection of land cover types for which the radar signal is mainly sensitive to soil moisture variations. Then a hydrological model is chosen, which can take advantage of the new information brought by remote sensing. The assimilation of soil moisture deduced from EO data into hydrological models is based principally on model parameter updating. The main assumption of this method is that the better the model simulates the current hydrological system, the better the following forecast will be. Another methodology used is a sequential one based on Kalman filtering. These methods have been put forward for use in the European AIMWATER project on the Seine catchment upstream of Paris (France) where dams are operated to alleviate floods in the Paris area.  相似文献   

会泽铅锌矿床中自然锑的发现及伴生元素的分布特征   总被引：5，自引：0，他引：5  

李朝阳  刘玉平  张乾  皮道会  张文兰  陈进 《矿床地质》2005,24(1):52-60

文章对会泽铅锌矿床的主要矿体进行了系统观察、采样，对其矿石进行了岩矿鉴定、化学分析(包括部分单矿物)和电子探针分析，并对其成矿作用做了探讨。首次在矿石中发现了自然锑，初步查明整个矿床中Ag，Cd，Ge，Cu，Sb等伴生元素的平均含量(wB／10^-6)分别为121．77、660．99、62．10、203．78和169．87，认为它们是晚成矿阶段形成的。  相似文献   

地质环境系统的概念与特征——以洞庭湖区地质环境系统为例   总被引：4，自引：0，他引：4  

张人权  梁杏  靳孟贵  皮建高 《地学前缘》2001,8(1):59-65

地质环境系统是对人类经济技术活动作出共同响应的一定范围内地质环境的有机整体 ,是复杂的人工自然复合系统。文中以洞庭湖区防洪减灾为例 ,探讨了地质环境系统的概念、特征与研究思路。地质环境系统具有边界不确定性 ,影响传递的远距性与滞后性 ,系统行为的取向性、不确定性、难控性与反直观性 ,系统的社会性与共享性。因此 ,必须从成生、发展的角度 ,对其进行多学科综合研究 ,把握自然状态下系统演变的固有规律 ,分析叠加人为活动后系统结构、功能的变化及其机制。顺应自然、约束自然与人类自身 ,是建立人与自然相互协调的优化地质环境系统的根本原则。  相似文献   

Color of the horizontal branch of globular clusters     

A. M. Éigenson 《Astrophysics》1973,9(3):255-257

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Model of horizontal branch and the age of globular clusters     

A. M. Éigenson 《Astrophysics》1973,9(3):249-254

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Possible role of superluminous radiation under pulsar conditions     

V. Ya. Éidman 《Astrophysics》1972,8(4):359-361

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微波辅助化学反应制备纳米高岭石     

费进波  田熙科杨起  罗东岳裴芳罗红玉  皮振邦 《岩石矿物学杂志》2006,25(4):335-337

为提高高岭石比表面积、孔隙率和吸附容量，利用微波辅助化学反应制备了尿素-高岭石复合物，进一步微波辐射使层状高岭石完全剥离并粉碎，经分散后得到了纳米高岭石。利用傅立叶红外光谱仪（FT-IR）、X射线粉晶衍射仪（XRD）、扫描电镜（SEM）和透射电镜（硎）进行了过程中样品结构、形貌和尺寸方面的表征。结果表明：同等条件下，通过微波辅助剥离并粉碎层状高岭石，时间只需30min，约为单一球磨的1／20，分散后的纳米高岭石平均粒径约为150nm。  相似文献   

GPS信号的差分相关捕获算法研究   总被引：2，自引：0，他引：2  

皮亦鸣  张婧  蔡昌听 《全球定位系统》2006,31(4):1-4

随着人们活动范围的日益扩大和周边环境的日益复杂，低信噪比环境下捕获卫星导航信号逐渐成为国内外研究的重点。本文分析两种常用的改善检测统计量信噪比的方法：相干累加和非相干累加，指出它们各自存在的问题。引出差分相关捕获算法，详细介绍差分相关捕获算法，分析了其数学模型。从理论上研究差分相关捕获算法的性能，并借助MATLAB仿真，分析各个参数对算法性能的影响，同时与相干／非相干累加算法进行比较。  相似文献