刺网损坏的原因及其预防     

秦明双 《广东海洋大学学报》1997,(1)

为避免刺网在生产过程过早损坏，以期达到延长刺网使用寿命和提高其获性能的目的，根据刺网在使用过程中损坏的情况，分析了刺网损坏的主要原因有2个方面，一是网具设计、装配不合理；二是在作业过程受外界因素影响而引发。并探讨相应的预防措施。  相似文献   

长葛县规划区地下水化学特征及其成因分析     

孙芳  王磊  刘坤书  刘庆军 《河南国土资源》2001,(4)

本文根据长葛市规划区地下水化学分析资料 ,利用污染指数法对该区地下水化学特征及其成因进行了初步分析 ,指出该区局部地下水的总硬度、溶解性总固体、硝酸盐污染指数大于 1的原因是生活、工业废物处理不当和引用污水灌溉而引起 ,并提出了该市地下水污染治理的建议  相似文献   

Study on methods of land use dynamic monitoring at county level     

Lin-yi Li  Fang Huang  Zhao-li Liu  En-pu Wan 《中国地理科学(英文版)》2001,11(2):181-185

Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring at county level, traditional remote sensing methods such as satellite imagery visual interpretation and computer classification can not meet its demand for accuracy. The result of 1: 10 000 land use investigation map has high accuracy, but this method can not be used to dynamically monitor the land use because of its big expenses, long period and difficulty in updating data. In this paper, the characteristics of physiognomy, climate and the status of land use in Dehui County are taken into consideration and a set of method, which takes use of 3S techniques and applies to Northeast China Plain, is come up with. When the land use type of a land parcel changed as a whole, the date updating can be make by changing its land type ID in the attribute table in a GIS. When the land use type of an irregular area changed, GPS receivers are used to position its border. This set of method is characteristic of high accuracy and low expenses. It gets the information of land use change timely and can be used to dynamically monitor the land use. Foundation item: Under the auspices of the key project of the National Ninth Five-year Plan (96-B02-01-07). Biography: LI Lin-yi (1968 —), female, a native of Jilin, Ph. D. candidate of Changchun Institute of Geography, the Chinese Academy of Sciences. Her research interest includes land use change monitoring and crop yield estimation using “3S” techniques.  相似文献   

Mechanics of sediment transport,Ning Chien and Wan Zhaohui, 1984, Science press,Beijing, china. No. of pages: 656 (in Chinese). Price: Hardback Y10.70, paperback Y7.90. SBSN 15031-525     

You Qin Li 《地球表面变化过程与地形》1991,16(4):377-377

  相似文献   

扬子地台北缘晚震旦世微古植物特征及意义     

陈会鑫  丁莲芳  秦洪宾 《地球科学与环境学报》1994,(3)

本文着重研究了扬子地台北缘上震旦统陡山沱组、灯影组及下寒武统下部岩家河段的微古植物组合特征。初步建立了Ⅰ、Ⅱ两个微古植物组合，分别与陡山沱村阶和灯影峡阶相对应，分析了微古植物组合在地层划分与对比及在震旦系－寒武系界线的划分上所起的作用。  相似文献   

Some characteristics of pulsations in radio bursts at 9.375 GHz     

Zhihai Qin  Guangli Huang 《Astrophysics and Space Science》1994,218(2):213-222

A type of pulsation in a time scale of seconds superimposed on microwave burst at 9.375 GHz has been found during the twenty-second solar active maximum period by us. This phenomenon is quite different from radio spike emission at decimeter and long centimeter wavelengths. The flux level of the bursts rises as the repetition rate of pulsations increases, following an approximate linear relationship. This feature resembles that at mm wavelength, but some other features are different. Some mechanisms for interpretation have been proposed.  相似文献   

桂北江南古陆南缘拗褶带中铅锌矿产成矿信息特征及预测标志     

王全明  王平安  方一平 《南方国土资源》1993,(2)

本文通过研究与总结前人成果基础上.对桂北江南古陆南缘拗褶带中铅锌矿进行成矿预测。文中侧重探讨了该带的成矿环境、典型矿床特征、控矿因素和地球物理、地球化学特征;综合地、物、化成矿信息.总结提出了7 条成矿预测标志:采用特征分析法对该带中的19个成矿单元进行资源定性预测评价,认为其铅锌矿资源潜力较大,有找矿前景。  相似文献   

依据GPS数据研究伽师及帕米尔东北侧1994～1998年地壳水平运动及其与强震群的关系     

秦小军  周硕愚  赵齐乐  乔学军  王琪 《大地测量与地球动力学》2001,21(4):1-8

利用伽师强震群区及帕米尔东北侧地区 1994～ 1998年的GPS监测成果 ,用DDA方法模拟了伽师强震群前后该地区地壳运动和应力应变的变化过程。结果表明 :在此期间伽师地区的应变以南北向挤压为主 ,伽师附近最大主应变变化达到 5× 10 - 8/a ,最大剪应变变化也超过 2 .5×10 - 8/a ,明显高于周边地区。伽师强震群的发生与GPS监测成果反映的该地区地壳运动和应力应变的变化存在明显的对应关系。GPS监测成果反映出在伽师地区有一应力应变变化的集中区域。通过在伽师强震群震中分布块体中强行沿其最大剪应力方向 (NE)增加一新的破裂 ,可使该块体应力应变下降至与周围块体相均衡 ,且能量可能沿柯坪断裂向东北方向传递。新增断裂的运动呈左旋 ,并导致其所在块体呈右旋运动  相似文献   

客户机/服务器结构的地图数据库分布管理     

吴金华  李芹芳 《地球科学与环境学报》2001,23(3):68-70

叙述了客户机/服务器结构的地图数据库发展的必要性,对客户机/服务器结构的地图数据库分布管理概念、结构及网络环境进行了论述和设计.  相似文献   

A New Approach for Studying Hubble Diagrams of Quasars   总被引：2，自引：0，他引：2  

Y.P. Qin  G.Z. Xie  J.C. Wang  M.C. He  J.H. Fan 《Astrophysics and Space Science》1997,253(1):19-26

In this paper, a new approach for studying Hubble diagrams of quasars is introduced. The purpose is to reduce the well-known very large scatter in the diagram. We believe that the scatter is mainly caused by the wide spread of luminosity distribution of quasars. Based on a large number of quasars having been discovered, we introduce a new quantity, the collective apparent magnitude of certain amount of quasars in a corresponding redshift interval, and make a plot of the collective apparent magnitude versus redshift with the data published by Hewitt and Burbidge (1993). The quantity is contributed by individual apparent luminosities as well as the luminosity distribution of quasars. Scatter is expected to be largely reduced in the corresponding diagram, and this is indeed true as shown by the figures. By discussing several possible effects and from the figures, we find that the assumption that redshifts of quasars are distance indicators is confirmed, and the standard cosmological model is supported. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献