测绘单位文书档案管理与应用系统开发研究     

高文超  赵春香  吴爱华 《北京测绘》2012,(5):72-74,69

数字化、信息化是当今档案事业发展趋势,本文详细介绍我院档案信息化建设过程中关于文书档案管理系统的建设背景、设计开发过程、使用情况等;系统提供了入库、查询服务、查阅、打印等功能,设计的多条件模糊检索充分考虑了用户特点和需求,具有很强的实用性。本文同时提出个人关于档案建设的发展方向与趋势等看法。  相似文献   

浅谈北京规划市区1:500地形图数字化测绘     

张立军 《北京测绘》2012,(6):95-98

地形图为国民经济建设和社会各行各业的发展提供测绘保障,它是城市规划设计、市政工程建设、工业与民用建筑、土地开发利用、防灾减灾等各方面的基础数据之一。本文结合北京城市基础测绘工作,以《BSCS G2000》测图软件为例,简述大比例尺数字化地形图的作业流程,地形要素取舍及检查验收工作。  相似文献   

Simulation of Lake-Groundwater Interaction under Steady-State Flow     

Chuiyu Lu  Bo Zhang  Xin He  Guoliang Cao  Qingyan Sun  Lingjia Yan  Tao Qin  Tianchen Li  Zepeng Li 《Ground water》2021,59(1):90-99

MODFLOW is one of the most popular groundwater simulation tools available; however, the development of lake modules that can be coupled with MODFLOW is lacking apart from the LAK3 package. This study proposes a new approach for simulating lake - groundwater interaction under steady-state flow, referred to as the sloping lakebed method (SLM). In this new approach, discretization of the lakebed in the vertical direction is independent of the spatial discretization of the aquifer system, which can potentially solve the problem that the lake and groundwater are usually simulated at different scales. The lakebed is generalized by a slant at the bottom of each lake grid cell, which can be classified as fully submerged, dry, and partly submerged. The SLM method accounts for all lake sources and sinks, establishing a governing equation that can be solved using Newton's method. A benchmarking case study was conducted using a modified model setup in the LAK3 user manual. It was found that when there is a sufficient number of layers at the top of the groundwater model, SLM simulates an almost identical groundwater head as the LAK3-based model; when the number of layers decreases, SLM is unaffected while LAK3 may be at a risk of giving unrealistic results. Additionally, the SLM can reflect the relationship between the simulated lake surface area and lake water depth more accurately. Therefore, the SLM method is a promising alternative to the LAK3 package when simulating lake - groundwater interaction.  相似文献   

Dynamic Regulation of Reservoir Drought Limit Water Level     

Runxiang Cao  Li  Fawen  Zhao  Yong 《Water Resources》2021,48(2):194-203

Water Resources - Drought limit water level has been presented to guide reservoir drought resistance for years. However, current static drought limit water levels neglected the water transfer...  相似文献   

Risk analysis for clustered check dams due to heavy rainfall   总被引：7，自引：1，他引：6  

Zuyu Chen  Xieping Huang  Shu Yu  Wei Cao  Weiqin Dang  Yangqiang Wang 《国际泥沙研究》2021,36(2):291-305

Check dams are commonly constructed around the world for alleviating soil erosion and preventing sedimentation of downstream rivers and reservoirs.Check dams are more vulnerable to failure due to their less stringent flood control standards compared to other dams.Determining the critical precipitation that will result in overtopping of a dam is a useful approach to assessing the risk of failure on a probabilistic basis and for providing early warning in case of an emergency.However,many check dams are built in groups,spreading in several tributaries in cascade forms,comprising a complex network.Determining the critical precipitation for dam overtopping requires a knowledge of its upstream dams on whether they survived or were overtopped during the same storm,while these upstream dams in turn need the information for their upstream dams.The current paper presents an approach of decomposing the dam cluster into(1)the heading dam,(2)border dams,and(3)intermediate dams.The algorithm begins with the border dams that have no upstream dams and proceeds with upgraded maps without the previous border dams until all the dams have been checked.It is believed that this approach is applicable for small-scale check dam systems where the time lag of flood routing can be neglected.As a pilot study,the current paper presents the analytical results for the Wangmaogou Check Dam System that has 22 dams connected in series and parallel.The algorithm clearly identified 7 surviving dams,with the remaining ones being overtopped for a storm of 179.6 mm in 12 h,which is associated with a return period of one in 200 years.  相似文献   

地面沉降对含水层参数及给水能力的影响研究          下载免费PDF全文

刘蓉  曹国亮  赵勇  陆垂裕  孙青言  严聆嘉  彭鹏 《水文地质工程地质》2019,(3):47-47

地面沉降主要由深层地下水开采造成,含水层的压缩释水是深层地下水开采量主要构成来源,同时随其压缩变形孔隙比减小造成储水系数、渗透系数的减小,对弱透水层非弹性释水量、越流补给量造成影响。地面沉降过程中的水文地质参数非线性变化及对承压含水层系统的反馈作用也成为水文地质领域的前沿问题。为对地下水开采量、沉降量、地质参数变化以及给水能力变化之间的关系做一个较为定量定性的探究,以含水层压缩过程中的物理机制为依据,并基于沧州地区深层承压含水层的地下水位变化过程和水文地质参数,采用数学手段构建储水系数和渗透系数变化的一维非线性沉降模型。模拟结果显示随承压水头下降,储水系数最高可减小77%,含水层系统的给水能力和储水能力会随压缩变形减小50%甚至更多。研究成果为深入认识水文地质参数与应力变化相关关系、科学评价承压含水层地下水储水调节能力有重要借鉴意义。  相似文献   

坡面流层流区动力学特性   总被引：1，自引：0，他引：1       下载免费PDF全文

杨苗  龚家国  赵勇  赵翠平 《水科学进展》2019,30(5):709-718

为完善坡面水流的基础理论研究,基于定床水槽试验,以甘油溶液为试验流体,采用超声波测量技术,进行了4种粗糙度、5种坡度和13种单宽流量条件下的组合试验,研究了坡面流层流区的动力学特性及滚波特征。研究结果表明:在雷诺数为8~160的范围内,流态指数在理论值0.33附近波动,且随粗糙度的增大呈现先增大后减小的变化趋势,在粗糙度为0.10 mm附近达到峰值;阻力系数受坡度和粗糙度影响显著,可较好地由坡度、粗糙度和雷诺数的关系式表示;随着雷诺数的增大,滚波波速和波峰均呈幂函数形式递增,滚波周期大小无明显变化;坡度的增大会使层流失稳临界单宽流量减小,粗糙度的增大会使临界弗劳德数的均值减小。  相似文献   

新疆和田普阳煤矿开采技术条件分析     

鲁艳平  祁斌 《中国煤炭地质》2019,(2):56-59

和田属南疆严重缺煤地区,布雅煤矿区是和田地区的主要煤产地。普阳煤矿含煤地层为侏罗系下统康苏组和侏罗系中统杨叶组。井田水文地质类型属孔隙、裂隙类简单型;工程地质类型属层状岩类复杂型;环境地质质量中等。  相似文献   

煤炭矿山资源储量动态变化类型与特征研究     

林中月  刘亢 《中国煤炭地质》2019,(4):23-25,41

通过对国内煤炭矿山资源储量动态变化原因研究,将其变化类型划分为:开采动用、重新核实、资源复采、资源压覆和界外动用五种类型,其中开采动用是储量变化的主体,存在于所有矿山,储量增减占比高(68.8%);重新核实是矿山有计划开展的储量修正补充,广泛存在(40.0%),储量增减占比低(4.3%);复采资源是矿山依靠工艺、设备提升改进回收的资源,存在于少数矿山(12.9%),储量增减占比非常低(1.1%);压覆资源仅存在个别矿山(8.6%),但引起储量变化量大(25.8%),需进行储量核减报批;界外动用是非法行为,需对违反的企业和个人依法进行处罚。  相似文献   

高分三号SAR影像双阈值变化检测   总被引：1，自引：1，他引：0  

崔斌  张永红  闫利  魏钜杰 《遥感学报》2020,24(1):1-10

双阈值合成孔径雷达SAR(Synthetic Aperture Radar)变化检测算法具有在发现变化区域的同时还能确定地表发生后向散射变化类型的优点。针对广义高斯双阈值最小误差法D-GKIT(Dual Generalized Kittler and Illingworth Thresholding)在进行阈值选取时直方图中不同类别像素灰度级重叠严重时,分割结果容易在尖峰单侧选取出双阈值而导致无法正确分割差异图的问题,本文提出一种结合归一化最大类间方差和广义高斯最小误差法GKIT(Generalized Kittler and Illingworth Thresholding)的双阈值SAR变化检测方法。首先,提出以归一化最大类间方差值作为灰度级重叠程度的判别参数,确定阈值的选取顺序及两个候选区间;然后,利用GKIT在候选区间内进行分割,获取单侧阈值及非变化类拟合函数;最后,提出利用非变化类拟合函数更新后的直方图作为另一侧阈值选取基础进行分割,得到对应分割阈值。以宁波地区高分三号(GF-3)SAR卫星影像作为试验研究数据,结果表明:本文方法能较好地解决灰度级重叠时D-GKIT无法进行正确分割的问题,具有良好的变化检测效果和更强的鲁棒性且达到了利用研究区数据验证利用GF-3号SAR卫星影像进行变化检测研究可行性的目的。  相似文献