土地利用现状图中数据缩编的质量控制分析     

李香莉  李恒利  蔡冬梅 《测绘与空间地理信息》2012,35(4):175-177

1∶50000土地利用现状图是土地利用研究的基础数据之一,编制土地利用现状图对制定河南省社会和经济中长期发展规划、土地利用总体规划和城乡规划,全面加强土地管理,促进全省经济发展起着非常重要的作用.本文结合1∶50000土地利用现状要素数据缩编工程质量检查工作实践,总结了质量检查的内容、技术要求及检查方法,提高了作业质量和效率.  相似文献   

天文观测科学实践中心技术实现     

林亲  卢晓猛  黎华丽  米琳莹  高东洋 《天文研究与技术》2012,(2):213-218

天文观测科学实践中心是一个以天文观测为核心的网络实践体验中心,以网站的形式向公众提供服务。网站建设使用HTML、CSS、JavaScript和JSP/JaveBean等技术;基于B/S结构实现望远镜远程控制;采用Windows Media技术实现视频发布。建成的网站为用户提供了全新的天文观测实践体验机会,达到了传播天文知识的目的。  相似文献   

Estimating bed material fluxes upstream and downstream of a controlled large bifurcation - the Mississippi-Atchafalaya River diversion     

Bo Wang  Yi-Jun Xu 《水文研究》2020,34(13):2864-2877

Bed material transport at river bifurcations is crucial for channel stability and downstream geomorphic dynamics. However, measurements of bed material transport at bifurcations of large alluvial rivers are difficult to make, and standard estimates based on the assumption of proportional partitioning of flow and bedload transport at bifurcations may be erroneous. In this study, we employed a combined approach based on observed topographic change (erosion/deposition) and bed material transport predicted from a one-dimensional model to investigate bed material fluxes near the engineering-controlled Mississippi-Atchafalaya River diversion, which is of great importance to sediment distribution and delivery to Louisiana's coast. Yang's (1973) sediment transport equation was utilized to estimate daily bed material loads upstream, downstream, and through the diversion during 2004–2013. Bathymetric changes in these channels were assessed with single beam data collected in 2004 and 2013. Results show that over the study period, 24% of the Mississippi River flow was diverted into the Atchafalaya River, while the rest remained in the mainstem Mississippi. Upstream of the diversion, the bed material yield was predicted to be 201 million metric tons (MT), of which approximately 35 MT (i.e., 17%) passed through the bifurcation channel to the Atchafalaya River. The findings from this study reveal that in the mainstem Mississippi, the percentage of bed material diversion (83%) is larger than the percentage of flow diversion (76%); Conversely, the diversion channel receives a disproportionate amount of flow (24%) relative to bed material supply (17%). Consequently, severe bed scouring occurred in the controlled Outflow Channel to the Atchafalaya River, while riverbed aggradation progressed in the mainstem Mississippi downstream of the diversion structures, implying reduced flow capacity and potential risk of a high backwater during megafloods. The study demonstrates that Yang's sediment transport equation provides plausible results of bed material fluxes for a highly complicated large river diversion, and that integration of the sediment transport equation with observed morphological changes in riverbed is a valuable approach to investigate sediment dynamics at controlled river bifurcations.  相似文献   

ArcGIS在矢量测绘数据质量控制中的应用     

谭福初  裴亚波  李广兰 《北京测绘》2007,(4):45-47

GIS应用和信息化测绘发展对测绘数据质量提出更高要求,本文通过对矢量测绘数据质量要素控制的简单分析,详细介绍了实际工作中运用ArcGIS对主要的质量要素进行控制检查的方法和步骤,对实施矢量测绘数据的质量控制具有实际意义。  相似文献   

洞庭湖综合治理中根治“地质灾害”的重要性     

李定雄  左小平 《湖南地质》1999,(Z1)

本文从洞庭湖区环境地质条件入手,分析堤防失事及所存在的险工险段与地质缺陷的关系,指出地质灾害是造成防洪工程失事不可忽视的因素。在洞庭湖区综合治理过程中,应注重对地质缺陷的治理  相似文献   

光化学烟雾的控制试验   总被引：2，自引：0，他引：2  

纪飞  苏文颖 《应用气象学报》1999,10(4):491-497

利用MM5与RADM的耦合模式,设计了3个削减源排放的试验,用以探讨控制光化学污染的有效途径。试验结果表明,在NMHC/NOx比值很大的前提条件下,NOx地面源排放的削减对降低大气中O3含量的作用最显著,而削减NMHC对降低大气中PAN含量的作用明显,同时削减NMHC和NOx是降低大气光化学污染强度的最佳途径。  相似文献   

云南广南县老寨湾金矿地质特征及找矿标志     

高李阳  顾雄  吴小梅 《云南地质》2020,(1):71-75

广南县老寨湾金矿位于滇、黔、桂“金三角”重要成矿区带上,金矿体矿体呈似层状赋存于断层构造破碎带或层间构造破碎带中,构造控矿明显。矿体围岩均为下泥盆统坡松冲组第一段(D1ps1)硅化石英砂岩;矿床成因属中-低温热液叠加改造型金矿床,断层构造、硅化等矿化蚀变及地球化学异常是重要的找矿标志。  相似文献   

中国的酸雨模拟及控制对策研究   总被引：16，自引：0，他引：16  

李宗恺  王体健 《气象科学》2000,21(3):339-347

本文以大气污染源、大气污染特征、降水化学特征和酸雨污染特征等方面论述了我国在气污染和酸雨污染属于“煤烟型”,并将我国的大气了环境状况与世界其它一些国家作了比较分析。进一步利用我们发展的南京大学酸沉降模式系统（ＮＪＵＡＤＭＳ）模拟了中国地区的ＳＯ２地面浓度和硫沉降分布,并与实际观测浆和亚洲酸雨模式（ＲＡＩＮＳ－ＡＳＬＡ）的计算结果作了比较。最后从能源结构和经济发展状况出发,论述了我国控制ＳＯ２污染和  相似文献   

Numerical investigation on the suppression of VIV for a circular cylinder by three small control rods     

《Applied Ocean Research》2017

Laminar flow past a circular cylinder with 3 small control rods is investigated by numerical simulation. This study is concerned with the suppression efficacy of vortex induced vibration by small control rods located around a main cylinder. The effects of the attack angle and rod-to-cylinder gap ratio on the hydrodynamics and vibration responses of the main cylinder are investigated. The attack angle of α = 45° is performed as the critical angle for VIV suppression of 3 control rods. The 3 control rods have no effect on VIV suppression when the attack angle is less than the critical angle. The 3 control rods have an excellent VIV suppression efficacy when the attack angle is larger than the critical angle. The transverse vibration frequency of the cylinder with 3 control rods is less than that for an isolated cylinder for all the configurations. The numerical results for the configurations of α = 45° & 60°, G/D = 0.6–1.2 show excellent suppression efficient among the cases investigated in this study. The best suppression efficient is found at α = 45°, G/D = 0.9 for 3 control rods. 2 rods in behind of the main cylinder perform more efficient than that of 1 rod in front for VIV suppression as the gap ratio of G/D less than 1.0.  相似文献   

西沙海域南部多边形断层的发现及其分布特征与控制因素     

杨涛涛  吕福亮  王彬  杨志力  李丽  张强 《海相油气地质》2017,22(1)

根据新采集的三维地震资料,在西沙海域南部发现了多边形断层,其发育分布具有层控特征明显、在富泥地层中发育、多方位走向、纵向断距小、平面延伸长度小且形态为不规则多边形等特征。由于研究区东西两侧应力条件的差异,导致多边形断层发育特征的差异明显。通过对多边形断层发育控制因素的分析,认为地层岩性(特别是西沙海域上构造层的远源细粒沉积物)是其发育的主控因素之一,同时水道砂岩、成岩作用及构造作用等也是影响其发育分布的因素。多边形断层可以作为流体运移的通道,它与下部构造断层连接可将深部烃源岩中的油气运移到上部储层中聚集,或继续向上运移到浅部地层中形成天然气水合物。  相似文献