直角与直线元素数字化的数据处理     

刘大杰  孟晓林 《武汉大学学报(信息科学版)》1997,(2)

结合地图数字化为ＧＩＳ采集空间数据的工作实际，对直角、直线数字化的数据处理的平差模型以及相应的精度评定方法进行了研究。作者认为，通过平差和评定精度，可以提高数字化的精度，并有助于实现对ＧＩＳ数据采集的质量控制  相似文献   

A field study of diffusion around a model cube in a suburban area   总被引：2，自引：0，他引：2  

Susumu Oikawa  Yan Meng 《Boundary-Layer Meteorology》1997,84(3):399-410

To investigate diffusion around a building in a suburban area, a field observation was conducted on a model cube with a centrally located rooftop level source in September 1992 in Sapporo, Japan. The results show that high concentrations were observed both upwind and downwind of the source on the roof, although the mean velocity U was positive. The values of normalized concentration at locations upwind and downwind of the source were lower than those obtained from wind tunnel data conducted at moderated turbulence levels. At ground level, the mean concentrations along the model centre line show the highest value near the cube and decay rapidly in the downstream direction. The relationship between the instantaneous concentrations and instantaneous velocity was investigated using two fast-response concentration detectors and an ultrasonic anemometer. It was found that when reverse flow occurred on the roof, the tracer gas was detected upwind of the source.  相似文献   

氡,汞测量用于断裂活动性和分段的研究   总被引：25，自引：1，他引：25  

孟广魁  何开明 《中国地震》1997,13(1):43-51

作者首先给出海原活动断裂带从边沟至硝口的３条较长次级剪切断层，干盐池拉分盆地和边沟推挤构造区内的断层，以及尾端挤压构造区内的六盘山东麓逆断层的气氡，气汞浓度测量结果，然后分析了断层气浓度与断层活动性之间的关系，研究结果表明，测试条件大体一致的基础上，气氡，气汞浓度与断层活动性之间有着明显的对应关系，从而证明了断层气测量方法对于活断层分段和活动性研究是一种有效的手段。  相似文献   

Factors governing the growth rate of roachRutilus rutilus (L.) in pre-alpine Lake Sarnen     

Rudolf Müller  Hans Jürg Meng 《Aquatic Sciences - Research Across Boundaries》1986,48(2):135-144

Most of the mesotrophic to eutrophic lakes in central Europe have been showing signs of oligotrophication during recent years. The question as to how the fish populations would react to this new situation was investigated looking at the growth rate of roachRutilus rutilus (L.) of Lake Sarnen, central Switzerland. The water temperature sum as day-degrees over 12 to 13°C for the months of June to October was found to be the predominant factor governing the marked year-to-year fluctuations of the growth rate. Contrary to expectation, the decreasing trophic state of the lake has not yet manifested itself noticeably in the growth rate.  相似文献   

植被覆盖区地质构造信息的数字图象处理          下载免费PDF全文

徐成彦  孟宪国 《地质科学》1987,(4):316-325

植被覆盖在我国南方具有普遍性。为了充分提取地质构造信息,有必要进行数字图象组合处理。事实证明,同态滤波处理是揭示植被覆盖区地质构造信息的有效手段,而主成分分析和斜变换处理在增强形态特征信息方面也有重要作用,上述处理手段在识别岩石类型及地貌单元方面也有很好的效果。  相似文献   

A preliminary study on the distribution and genesis of underground brine in the littoral plain of Laizhou Bay in the Bohai Sea   总被引：3，自引：1，他引：2  

韩有松  孟广兰  王少青 《中国海洋湖沼学报》1993,11(1):46-56

Quaternary underground brine in the littoral plain region of the Bohai coast is new type littoral facies evaporation ore deposit in liquid state . This model of " littorally- forming brine " is based on study of the distribution, depositional environment, forming / storing process, and genesis of underground brine in the coast of Laizhou Bay . Essential conditions for genesis of brine are arid and semiarid climate , abundant sources of ancient seawater, and geological and geomorphological environment of wide tidal beach along a coast. The process of underground brine genesis may be : seawater/tidal beach-evaporation and concentration-seeping and accumulation- brine/tidal beach - burial (evolution of the sea- land )- underground brine .Underground brine is characterized by high content of chemical elements, shallow burial depth and easy exploitation . The process of extracting salt from underground brine present in the tidal flat is incomparably superior to that of producing salt from seawater, and has b  相似文献   

Historical changes in heavy metals in the Yangtze Estuary, China   总被引：1，自引：0，他引：1  

Meng Yang  Ray Kostaschuk  Zhongyuan Chen 《Environmental Geology》2004,46(6-7):857-864

A 6-m-long core was used to examine historical changes in heavy metals on tidal flats in the Yangtze Estuary, China. Over the last 100 years, human impact was minimal. However, over the last few decades, vertical metal concentrations have been affected by human activities such as local industrialization, urbanization and construction of major sewage outlets. Copper, lead and arsenic were identified as contaminants in the Yangtze Estuary on the basis of national pollution standards and a comparison of metals in the upper core with those in the lower core.  相似文献   

Mianlüe tectonic zone and Mianlüe suture zone on southern margin of Qinling-Dabie orogenic belt     

ZHANG Guowei  Dong Yunpeng  Lai Shaocong  GUO anlin  Meng Qingren  Liu Shaofeng  CHENG Shunyou  Yao Anping  ZHANG Zongqing  PEI Xianzhi  Li Sanzhong 《中国科学D辑(英文版)》2004,47(4)

The Mianlue tectonic zone (Mianlue zone), an ancient suture zone in addition to theShangdan suture in the Qinling-Dabie orogenic belt, marks an important tectonic division geo-logically separating north from south and connecting east with west in China continent. To de-termine present structural geometry and kinematics in the Mianlue tectonic zone and to recon-struct the formation and evolution history involving plate subduction and collision in theQinling-Dabie orogenic belt, through a multidisciplinary study, are significant for exploring themountain-building orogenesis of the central orogenic system and the entire process of the majorChinese continental amalgamation during the Indosinian.  相似文献   

北山—阿拉善地区白垩纪、侏罗纪盆地叠合特征   总被引：3，自引：0，他引：3  

郑孟林  李明杰  曹春潮  张军勇 《大地构造与成矿学》2003,27(4):384-389

研究区发育侏罗纪盆地和白垩纪盆地,侏罗纪盆地受近东西向断裂的控制,为东西向展布的断陷湖盆。白垩纪盆地受北东向断裂的控制,为北东向展布的断陷湖盆,经历早白垩世的伸展断陷及其以后的后期改造阶段。两大世代的盆地在空间上存在翘倾叠合、叠合保存、部分叠合改造等三种方式。盆地的叠合保存对侏罗系烃源岩的油气形成最为有利。  相似文献   

测震学信息增益合成方法及其在地震预报中的应用     

孟保成  王志铄  张亚琳  苏莉华  陈琴 《地震研究》2003,26(1):43-49

提出了一种地震预报的新方法，并应用于地震的地点预测。震例的空间扫描异常区的对比表明，该方法比单项地震预报方法圈出的异常区不仅范围小，而且包围或接近震中。  相似文献