首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
多协议标记交换技术是一种全瓶的网络交换技术,它的成功应用,将会解决目前IP网络上存在的众多问题。阐述了多协议标记交换技术的原理、关键技术等,并简单介绍在虚拟专用网、流量工程、Qos等方面的应用。  相似文献   

2.
国土资源信息蕴涵了多种数据类型和海量的数据,而且在日常管理和经营中还不断产生新的数据,为了更好地获取和利用国土资源信息,迫切需要解决国土资源管理部门定期更新或交换数据的任务,其中,空间数据是数据交换的重点和难点。本文介绍了在国土资源行业之间空间信息交换的总体思想,即在实现国家一级数据中心的基础上,由市地、省到国家级数据中心的数据逐级汇总和增量备份的方式,并进一步分析了国土资源信息交换体系的实现模式以及可采用的技术等方面内容,最后介绍了国土资源信息交换体系建设的实践。  相似文献   

3.
针对目前城市众多管理部门对城市GIS数据共享交换平台不同层次的共享需求,在分析文件级、数据平台级、系统功能级以及Web服务级四种共享交换模式特点的基础上,本文采用业务流技术设计了一种集成多级共享交换模式的数据模型。结合无锡市地理信息共享交换平台项目的建设,给出了模型在城市GIS数据交换平台系统中的具体应用过程,以期对其他城市同类系统的建设提供一定的参考价值。  相似文献   

4.
上海城市空间基础地理信息的建设与发展   总被引:2,自引:0,他引:2  
城市是信息化进程最快、信息交换程度最高的区域,它对空间信息的需求呈现出比例尺大、更新周期短、社会对空间信息需求量大等3个方面特点。本文对上海城市空间基础地理信息的建设历程进行了回顾,并就现阶段主要任务和发展作了展望。  相似文献   

5.
关于非球形粒子光散射的T-矩阵数值计算方法的研究   总被引:1,自引:0,他引:1  
首先介绍了无规取向轴对称非球形粒子光散射的T-矩阵数值方法。然后,进一步研究了T-矩阵计算的收敛问题,提出了一种新的关于无规取向无吸收非线形散射物体的物理收敛方法,我们研究了椭球粒子的收敛问题,结果表明我们的数值方法和T-矩阵计算程序是有效的, 收敛精度与粒子的尺度和形状有很强的依赖性,在一定的条件下,我们的物理收敛速度优于NASA Mishchenko的数学收敛速序。  相似文献   

6.
改性提高膨润土阳离子交换容量研究   总被引:2,自引:0,他引:2  
研究了焙烧活化、酸活化、氯化钠活化、溴化十六烷基三甲铵活化等改性方法对膨润土阳离子交换容量的影响。结果表明,450℃焙烧2 h,膨润土阳离子交换容量可提高30%以上,0.01 mol.L-1氯化钠和0.3 mol.L-1溴化十六烷基三甲铵活化处理均可使膨润土阳离子交换容量提高10%以上,0.1 mol.L-1盐酸活化处理对提高膨润土的阳离子交换容量效果不明显,还深入讨论了改性提高澎润土阳离子交换容量的机理。  相似文献   

7.
Mapsource是Gps和计算机之间数据交换的一种常见软件,较广泛应用于野外地质、测量工作中。但Mapsource、GPS一次仅能输入航点,使其应用受到很大限制,一些专业人士主要是利用一些小软件进行数据转换,但大多数地质工作者却因无法得到或不会使用这种软件而苦恼。笔者通过对GPS交换格式(GPS设备中的地图信息格式,用于在GPS设备和网络间交换数据)深入研究,借助记事本、Excel产生GPX交换数据,成功实现向Map—SoHrce批量输入航点,完善了Mapsource功能,进而实现向GPS批量输入航点,提高了地质工作效率,受到众多地质工作者好评。  相似文献   

8.
扼要地介绍了非球形粒子光散射的散射矩阵元素按广义球函数展开的基本理论,以及球形粒子散射矩阵元素间的关系。在此基础上较详细地阐述了计算展开系数的方法以及在程序研制中所遇到的一些问题。最后,对非球形的Chebyshev粒子光散射的散射矩阵元素的展开系数进行了计算,结果表明数值技术和计算的正确性。  相似文献   

9.
温度变化对土壤水运动影响研究   总被引:5,自引:0,他引:5  
探讨了土壤温度的日、年变化规律及土壤温度梯度的变化特点,分析了土壤水分运动及土壤水和潜水之间的水分交换规律与土壤温度变化之间的关系。通过实验和分析证实,温度的日变化是引起浅层地下水位日变化的主要原因之一。  相似文献   

10.
简要介绍ML-1型稳频激光器的红、蓝光工作模式,对其单光、双光测量结果进行实验,并与FG5X型绝对重力仪的观测结果进行对比。结果表明,ML-1型激光器红、蓝光工作模式可有效减小稳频激光器温度及时间的漂移对绝对重力观测的影响,红蓝分离值的大小表征了激光器漂移的程度,若红蓝分离值较大,表明稳频激光器存在较大漂移,需进行标定校准。  相似文献   

11.
12.
Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.  相似文献   

13.
Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter.  相似文献   

14.
正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied  相似文献   

15.
16.
《山地科学学报》2014,(4):I0004-I0009
<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet.  相似文献   

17.
<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by  相似文献   

18.
Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated.  相似文献   

19.
20.
<正>The Journal of Ocean University of China(Oceanic and Coastal Sea Research)is a comprehensive academic quarterly sponsored by the Ocean University of China,published one volume per year.This journal is devoted to the publication of the theoretical and applied research  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号