黄河下游的河性   总被引：8，自引：0，他引：8  

尹学良  陈金荣 《地理学报》1992,47(3):193-207

本文探讨了黄河一般特性的综合关系,讨论了河道演变中均衡与非均衡的问题、滩槽冲淤的利与害和主与从的问题,同时讨论了河道冲淤演变特性、与水沙条件的关系、河槽淤积率和淤积比等。  相似文献   

吉黑东部斑岩型-浅成热液型铜金矿床多重成矿模型   总被引：5，自引：0，他引：5  

芮宗瑶  张洪涛  王龙生  陈仁义 《矿床地质》1995,14(2):174-184

通过四个典型矿床（小西南岔、闹枝、五凤和刺猬沟）的对比，发现它们在形成时间-空间一成因上既相互联系，又相互区别。小西南岔和闹枝矿床存在三个成矿流体系统：加热天水系统(A)、排放流体系统(B)、蒸气缕(steam plume)反应系统(C)；五凤和刺猬沟矿床只有一个成矿流体系统，即排放流体系统(B)。前者的成矿流体由浅成岩浆房的补给；后者的成矿流体主要为循环天水，浅成岩浆房的补给不明显。小西南岔金铜矿床产于中生代火山岩盆地边缘的隆起带，属于斑岩型矿床；闹枝金（铜）矿床产于中生代火山岩盆地内的断隆块，属于斑岩-浅成热液过渡型矿床；五凤和刺猬沟金（银）矿床产于中生代火山岩盆地内断裂带，属于浅成热液型矿床。在区域成矿上，由浅入深，浅成热液型斑岩-浅成热液过渡型和斑岩型构成多重成矿模型。  相似文献   

Quantitative analysis of springs   总被引：1，自引：0，他引：1  

B. A. Memon 《Environmental Geology》1995,26(2):111-120

Growing demand for groundwater resources and stringent environmental concerns has led to large groundwater investigations, including characterization of aquifer systems that are hydraulically connected to springs. A pumping test is one of the most reliable means of quantifying hydraulic characteristics and the response of natural springs to pumping because it yields results that, in general, are representative of a larger area than are results from a single point observation. Recharge to the aquifer sustaining discharge from springs must be evaluated prior to the utilization of springs. The spring hydrograph is analyzed, as the shape of a hydrograph is a reflection of the response of the aquifer to recharge. The form and rate of recession provide significant information on the storage, lithological composition, and structural characteristics of the aquifer system sustaining the spring. Water tracing techniques have been developed and used over a period of centuries to delineate catchment boundaries, estimate groundwater flow velocities, determine areas of recharge, and identify sources of pollution of spring water.  相似文献   

电导率法在入河排污口流量监测中的应用研究     

郭金巨  张武云 《水文》2006,26(2):64-67

鉴于目前入河排污口流量测验手段不足,尝试采用测试电导率方法进行排污口流量测量,并与常规流量测验方法容量法进行比对,试验证实本方法简便易行,适应性强,可以在实际工作中推广应用。  相似文献   

雪崩、分形与雷暴放电中强闪的自组织演化     

苟学强  张义军  董万胜  郄秀书 《高原气象》2006,25(5):849-854

强调了雪崩、分形与远离平衡系统自组织演化的联系。利用2003年夏季青藏高原中部地区雷暴放电的地面电场野外观测资料,基于近年来发展的分形及多重分形分析中的去势涨落分析(detrend-ed fluctuation analysis,DFA)方法,对强闪前电场信号的关联及多重分形特征进行了分析,发现强放电前过程具有明显的分形和多重分形特征,多重分形谱与推广的二项倍增串级模式符合。分析在一定程度上表明了雷暴强放电发生的可能的自组织演化性。  相似文献   

THE ENERGETIC AGGREGATION AND RESLEASE IN THE HEAVY RAIN REGION     

周海光  刘海涛  刘延英 《热带气象学报(英文版)》2006,12(1):29-33

Using the new formula of moist available energy (MAE), the value of the MAE’s key terms of three heavy rainfall cases in Guangdong province in 1998 was calculated. The energetic aggregation and energetic discharge are analyzed. It shows that the value of the key terms in the formula appears different feature clearly in the different precipitation period, as well as the function of each term presents in the heavy rain region.  相似文献   

Some observations of bipolar flashes during summer thunderstorms near Warsaw     

Piotr Barański  Paweł Bodzak 《Acta Geophysica》2006,54(1):71-89

Lightning discharges monitored by the SAFIR network system in Poland have been additionally identified over the 100×100 km area near Warsaw by single-point independent recordings of electric field and Maxwell current rapid changes. The data collected in summer thunderstorm days of 2002 showed some untypical properties of the lightning discharges which are rarely observed. Especially remarkable was a number of ground multi-stroke flashes with the return strokes (RS) which transported to the earth charges of opposite signs. Bipolar flashes (BF) of this kind were mostly involved in the events in which the nearby intracloud (ic) and cloud-to-ground (c-g) discharges were very closely associated in time. Events of such a close collocation of two different types of lightning discharges, previously called the complex lightning discharge events (CLDE), were quite often observed during summer thunderstorms in Poland. The events of this kind, i.e. 8 flashes, identified by the SAFIR detection system as BF’s present the multiple stroke flashes of the mean horizontal separation distance between striking points of particular RS equal to (2.8 ± 2.1) km and of the mean time interval between strokes of (46.8 ± 74.4) ms. The time separation between the observed BF and the adjacent ic flashes was from 0.1 to 335 ms, and horizontal separation distance between them ranged from 1.8 to 14.5 km. The multiplicity of the recorded BF’s ranged from 2 to 4 strokes. Four of these BF’s followed the ic discharge, but the other three preceded the ic and one was alone with no close ic.  相似文献   

浅谈地下水流模拟中河流的处理方法   总被引：3，自引：0，他引：3  

谭杰  王杰  杨操静 《地下水》2006,28(4):28-30

本文分析了河水与地下水不同作用形式下的补排关系,给出了河流在地下水流模拟中的两种处理方法.根据河流与地下水的相互作用规律将其概化为四种边界条件,并给出了在不同边界条件中河水与地下水交换量的计算公式,初步建立了河水与地下水的解析耦合模型.  相似文献   

重庆走马岭岩溶隧道涌水量初步研究   总被引：3，自引：2，他引：3  

康小兵  张强  许模 《工程地质学报》2006,14(1):68-71

隧道涌水问题普遍存在,从隧道的施工到竣工运行都受其影响,特别是在南方岩溶地区尤为严重。根据勘察资料,走马岭隧道穿越可溶岩段(含断层破碎带)长1525m,占隧道总长的62%,极易发生隧道涌水事故。本文结合已开挖段隧道涌水的实时监测数据及前期工程勘察资料,对隧道涌水做出初步预测评价,为以后的施工提供依据。  相似文献   

圆形断面管道非满流流速计算表达式   总被引：1，自引：0，他引：1       下载免费PDF全文

茅泽育  赵璇  罗昇 《水科学进展》2007,18(2):170-174

工程实际中,常需要计算某一充满度下管道非满流的流量及流速。目前大多数计算模型均采用水力半径作为反映过流断面形状及几何尺寸的特征参数。针对不同充满度的研究结果表明,这种类型模型的计算结果与真实的流动特性并不相符,尤其当水深接近管顶时。根据水动力学基本原理及试验研究手段,对圆形断面管道无压均匀流流量-充满度非单一性进行了探索,并提出了以流量作为形状特征参数的更为合理且简单实用的水流流速计算表达式。  相似文献