逍遥村水源地岩溶水系统与孔隙水系统关系浅析     

王宏珍 《河南地质》1998,16(2):121-125

概述了逍遥村水源地的自然地理、水文地质概况和逍遥河岩溶子系统的边界条件及主要含水系统。论证了财溶水和孔隙水在子系统内没有水力联系。  相似文献   

中硬岩石水力反循环连续取心钻探工艺的研究与应用     

张永勤  张晓西 《城市地质》1998,10(2):16-21

１概述水力反循环连续取心钻探技术是近代岩心钻探的一项新技术,该技术利用双壁钻杆把冲洗液（清水或泥浆）经内外钻杆的环隙输送到孔底,然后,把随着钻进的进行而产生的岩屑和岩心经内钻杆的中心通道携带至地表,从而实现了无须停止钻进和提出孔内钻杆就能连续获得所需...  相似文献   

膨胀地球基本参数的初值及其平均变化率   总被引：6，自引：0，他引：6       下载免费PDF全文

陈志耕 《地球物理学报》1990,33(5):611-618

本文讨论了地球膨胀过程的初始半径R₀、膨胀起始时间t₀以及半径R、转动惯量I、地表重力加速度g和反映地球内部物质分布状态参数y等膨胀基本参数的平均变化率。研究结果表明,在地球的地质年龄之内,地球膨胀的初始半径R₀>4619km,膨胀的起始时间t₀>43.8×10²Ma,膨胀过程中的地球半径R、物质分布状态参数y、转动惯量I、地表重力加速度g和表面积S随时间的平均变化率分别为:dR/dt=4×10^-4m/a,dy/dt=-6.7×10¹²/a,dI/dt=8.49×10²⁷kg·m~2/a,dg/dt=-1.23×10^-10kg·s^-2/a和ds/dt=6.41×10⁴m²/a。地球膨胀过程中的半径平均增长率,是首次用天文学方法研究得出,且该值介于其他作者用古地磁、古地理等方法所求得的地球半径增长率若干数值之间。  相似文献   

苏通长江公路大桥桥区河床抗冲性能试验研究   总被引：1，自引：0，他引：1  

洪大林 谢瑞张思和  唐存本 《海洋工程》2003,21(4):91-96

针对交通、水利工程中遇到的实际问题，采用现场原状土取样，并通过封闭管道水力试验，得到原状土起动的临界切应力及冲刷率，并通过公式换算得到原状土的起动流速，这一方法可用来确定物理模型试验中动床模型设计参数，并可为设计部门提供科学依据。  相似文献   

Physical Hydrography and Algal Bloom Transport in Hong Kong Waters   总被引：2，自引：1，他引：2  

匡翠萍  李行伟 《中国海洋工程》2005,19(4):539-556

In sub-tropical coastal waters around Hong Kong, algal blooms and red tides are usually first sighted in the Mirs Bay, in the eastern waters of Hong Kong. A calibrated three-dimensional hydrodynamic model for the Pearl River Estuary （Delft3D） has been applied to the study of the physical hydrography of Hong Kong waters and its relationship with algal bloom transport patterns in the dry and wet seasons. The general 3D hydrodynamic circulation and salinity structure in the partially-mixed estuary are presented. Extensive numerical surface drogue tracking experiments are performed for algal blooms that are initiated in the Mirs Bay under different seasonal, wind and tidal conditions. The probability of bloom impact on the Victoria Harbour and nearby urban coastal waters is estimated. The computations show that： i） In the wet season （May - August）, algal blooms initiated in the Mirs Bay will move in a clockwise direction out of the bay, and be transported away from Hong Kong due to SW monsoon winds which drive the SW to NE coastal current; ii） In the dry season （November- April）, algal blooms initiated in the northeast Mirs Bay will move in an anti-clockwise direction and be carried away into southern waters due to the NE to SW coastal current driven by the NE monsoon winds; the bloom typically flows past the east edge of the Victoria Harbeur and nearby waters. Finally, the role of hydrodynamic transport in an important episodic event -- the spring 1998 massive red tide -- is quantitatively examined. It is shown that the strong NE to E wind during late March to early April, coupled with the diurnal tide at the beginning of April, significantly increased the probability of bloom transport into the Port Shelter and East Lamma Channel, resulting in the massive fish kill. The results provide a basis for risk assessment of harmful algal bloom （HAB） impact on urban coastal waters around the Victoria Habour.  相似文献   

A model study of influence of circulation on the pollutant transport in the Zhujiang River Estuary and adjacent coastal waters   总被引：1，自引：1，他引：1  

WONG Lai Ah  GUAN Weibing  CHEN Jay-Chung  SU Jilan 《海洋学报(英文版)》2004,23(2):225-237

A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.  相似文献   

SAR图像不同油膜特征的最佳分割方法选择     

王志勇  王士帅  王世超 《测绘工程》2017,26(1)

SAR图像溢油分割是SAR溢油监测中一个重要环节。文中选取4种不同形状、尺寸和对比度的SAR油膜数据,分别采用双峰阈值分割法、最大熵分割法、区域生长法、分水岭算法、图割法、水平集方法等6种方法进行溢油信息提取,探讨适合于不同油膜特征的最佳提取方法。结合现有尺度分割标准,提出一种SAR图像溢油信息评价指数——有效分割指数(Effective Segmentation Index,ESI),对不同分割方法得到的溢油提取结果进行定量评价,得出了不同特征油膜所适合的最佳分割方法。  相似文献   

一种简单平面多边形的快速分割方法     

赖靖敏 《北京测绘》2017,(5):123-126

根据二分法的原理设计了一种简单平面多边形的快速分割算法,并利用ArcEngine提供的编程接口对该算法进行了实现,最后对算法进行了测试。实验结果验证了该算法的收敛特性,可以较好地控制分割精度,在满足精度要求的前提下实现多边形按面积或按比例任意份的分割,具有操作方便,参数控制灵活的优点。  相似文献   

基于先验统计知识和文字线的地名提取方法     

吴铮  刘新贵  宋华标  赵云鹏 《测绘与空间地理信息》2017,(2):79-81

对扫描地图地名注记的自动提取进行了研究,针对复杂背景扫描地图设计了一种新的地名注记提取方法。首先,运用先验统计知识对地名注记所在要素层进行分割;然后,将文字线组合方法与数学形态学膨胀算法结合实现了地名注记的高效提取。通过大量实验表明,该方法有效地克服了复杂背景下地名注记提取的困难,简单、快速且正确率较高。  相似文献   

面向对象的天绘遥感影像分类     

《地理空间信息》2017,(4)

天绘一号是我国第一代传输型立体测绘卫星,主要用于科学研究、国土资源普查、地图测绘等领域的科学实验任务。以天绘影像为实验数据,利用面向对象的影像分割技术,通过选择合适的尺度参数对影像进行分割。结合SVM对得到的影像对象层进行分类实验。具体分析了SVM分类器核函数的选择以及参数的设置对分类精度的影响。最终分类实验结果的总体精度为90.857 1%,Kappa系数为0.858 1。将分类结果与传统基于像元的马氏距离分类法和最大似然值分类法的分类结果进行比较,总体精度分别提高了约29.29%、5.91%,Kappa系数分别提高了约0.35、0.06。实验结果表明,面向对象的SVM分类法不仅对影像分类的精度有大幅度的提高,同时,也很好地解决了传统基于像素分类法出现的"椒盐"现象,是一种很有优势的影像分类法。  相似文献