Detection and correction of inconsistencies between river networks and contour data by spatial constraint knowledge

In the representation of topographic data, the distribution of hydrographic networks should be constrained by the contour model’s landform features. During the integration of topographic databases, however, spatial conflicts may destroy these constraints, generating inconsistencies. This study presents a method to detect and correct inconsistencies between river networks and contour data by spatial knowledge. First, structured terrain features are extracted from the contour-based geometric representation and matching relationships between rivers and contours are constructed based on spatial knowledge of the distribution of rivers and talwegs. We then propose a distance metric for measuring differences and identifying inconsistencies between the matched river and contour features. Three correction approaches are provided for different inconsistency situations, including river adjustment referenced to the contour, contour adjustment referenced to the river and adjustment of both river and contour to middle positions. We apply the proposed method to the integration and maintenance of national topographic infrastructure in order to demonstrate its effectiveness.     

红黏土承载比的土团尺寸效应研究

高液限红黏土用于路基填筑时,因其不良的水理特性,需要掺石灰或水泥改良。但红黏土成团现象十分突出,进行灰土拌和时不易达到均匀状态,影响预期改良效果。通过对不同直径的红黏土土团及石灰改良土土团进行承载比试验,结果表明：干密度随着土团直径尺寸的增大呈现先增大后减小的特征,红黏土和石灰土的最大干密度对应的土团直径处在0.2～ 5 mm范围内;而最大承载比CBR值对应的土团直径分别处在5～10 mm和2～5 mm的范围内。石灰土和红黏土的吸水率、膨胀率均随着土团尺寸的增大,呈现先减小后增大的整体变化趋势。在2～10 mm的范围内,两种土的膨胀量最小。石灰改良只对直径小于5 mm的土团的膨胀特性起到明显的抑制作用。可见,现场施工中严格控制土团的大小对保证土体的强度和水稳定性具有十分重要的意义。     

必须应用软件工程的方法开发GIS软件

简要介绍了GIS的软件功能，指出在软件设计中没有采用先进的软件工程方法给我国的GIS软件开发赞成了严重后果，在分析原因的基础上提出了解决建议并强调必须应用软件工程的方法开发GIS软件。     

模糊综合评判模型在宝坻水源地地下水水质评价中的应用

运用模糊综合评判模型,对中石化天津分公司宝坻水源地奥陶系灰岩地下水水质行综合评价。评价结果表明,研究区采样点水质总体评判级别为I级,说明该区地下水水质较好,而氟离子含量超标是由于地区背景值造成的,这一结论与该区其它研究成果评价结果一致。说明模糊综合评判模型是一种较实用的地下水水质评判方法。     

三江平原湿地消长与区域气候变化关系研究

以遥感手段为主,提取近20年来多个时期三江平原湿地变化动态数据。将湿地动态数据与历年气象数据相对变化比较处理后,再作灰色关联分析,可以发现它们之间的相互关系。研究表明三江平原湿地面积减小迅速,三江平原区域气候环境变化剧烈,超过全球气候变化速度。通过灰色关联分析可以发现,湿地在维持区域"冷湿"效应中作用突出,三江平原湿地的变化与气温变化成负相关,与降水、湿度变化成正相关。湿地消长与气候要素中的降水因子的相关关系最大,与日照因子相关关系较低,与降雪因子几乎无关。     

福建省福清市农业综合开发

经调查总结了福建省福清市１９７９年改革开放以来，发挥山海侨三者优势，发展外向型农业的成就，以及其主要作法和经验．     

苍山5.2级地震异常群体时空演化特征

在对 1 995年山东省苍山 5 2级地震异常筛选的基础上 ,分析了异常群体阶段性演化过程。结果表明 ,震前 1 0a左右震中周围出现小震小区域综合断层面解主压应力P轴偏转 (约 3 0°) ,震前 7a左右震中附近 3～ 4级地震增强集中及应变释放加速 ;震前 4a左右转为异常平静 ;震前 1a左右震中外围开始出现形变类前兆异常 ,前兆异常台站比和异常台项比约达 6%及 4%左右 ,异常比例偏少 ;震前约半年起 ,以震中附近地震波速比异常出现为起点 ,相继出现各类前兆异常 6条 ,短期前兆异常台站比和异常台项比分别约达 2 5 %和 1 7%左右 ,显示孕震进入短期阶段 ,但临震异常不明显。对由此获得的 5级地震预测启示进行了讨论。     

The twentieth century contiguous US temperature changes indicated by daily data and higher statistical moments

The daily surface air temperature data are used to assess the climate changes of the contiguous United States during the period of 1901 to 2000. The assessment is made through the first four statistical moments of the daily maximum, minimum, and mean temperature anomalies, the linear trends of the moments, and the changes of the anomalies?? probability density functions. The results on the first moment, i.e., the mean, are compared with the existing ones in terms of intra-annual means and their linear trends. Our first moment results agree with known ones and demonstrate a decrease from the 1930s to the 1960s and an increase from the 1970s to 2000. The temperature fluctuation is the smallest in the 1960s among the decades from 1931 to 2000. The trends of the higher (second-, third- and fourth-order) moments of the mean, maximum, and minimum surface air temperatures are calculated for the periods 1901?C2000, 1910?C1945, 1946?C1975, and 1976?C2000. The results show a decreasing trend of the second- and third-order moments of all the temperatures. The fourth-order moments of the mean and maximum surface air temperatures have increasing trends, but that of the minimum surface air temperature has a decreasing trend. The seasonal histograms of the mean, maximum, and minimum surface air temperatures are calculated for the three periods 1910?C1945, 1946?C1975, and 1976?C2000 for the stations which have the largest trend of maximum daily surface air temperature. An obvious change has been identified in the probability density functions. Among the changes of statistical parameters, the ones for the minimum temperature are larger than those for the maximum and mean temperatures.     

秦岭环斑花岗岩的年代学研究及其意义

本文对秦岭环斑花岗岩带进行了系统的测年工作,通过对实测Ｕ－Ｐｂ,Ｒｂ－Ｓｒ,＾４０Ａｒ／＾３９Ａｒ年龄测定结果研究,认为２１０－２１７Ｍａ是秦岭造山带主造山阶段结束的时间,为秦岭主造山期结束提供了确切的语气具有重要的科学意义。     

基于ETABS的钢筋混凝土框架与楼梯共同工作性能分析

本文利用大型结构分析软件ETABS设计了4种包含和不包含楼梯的钢筋混凝土框架计算模型,分别采用底部剪力法、反应谱法和时程分析法对各模型进行了弹性阶段地震反应特性对比计算分析.结果显示:楼梯参与结构整体计算后,结构出现抗侧刚度明显增加、结构扭转振动显著、梯间框架柱剪力突变等现象;建议结构设计时采用包含楼梯的层间结构计算模型(M-4),使用振型分解反应谱法进行结构抗震分析计算.