大中小震与抗震设防标准   总被引：5，自引：1，他引：4       下载免费PDF全文

沈建文  石树中 《地震学报》2004,26(5):533-538

讨论二级抗震设计与超越概率标准、概率法与综合概率法给出的3个水平的地震动的关系. 通过危险性分析的实际例子,讨论了50年超越概率2%、10%和63%的地震动,即大震、中震和小震的相对大小关系,并提出抗震设防标准的确定方法.   相似文献   

Geospatial-temporal analysis of land-use changes in the Yellow River Delta during the last 40 years   总被引：5，自引：0，他引：5  

Qinghua?YeEmail author  Gaohuan?Liu  Guoliang?Tian  Shenliang?Chen  Chong?Huang  Shupeng?Chen  Qingshen?Liu  Jun?Chang  Yanan?Shi 《中国科学D辑(英文版)》2004,47(11):1008-1024

Research on land use/land cover changes (LUCC)has been the core project of the Global EnvironmentalChanges since the 1990s[1—6]. Scientists at home andabroad have been laying emphasis on integrationstudies on land-use change by “space and process”features[7—10] as researches on LUCC are in a greatdeal. It is of paramount important for us to studyLUCC at various spatial-temporal scales and build aquantitative assessment of land-use conversion by in-tegrated spatial-temporal features. …  相似文献   

Investigations and assessment of the landslide hazards of Fengdu county in the reservoir region of the Three Gorges project on the Yangtze River   总被引：12，自引：0，他引：12  

Shuren?WuEmail author  Yimin?Jin  Yongshuang?Zhang  Jusong?Shi  Chen?Dong  Weizhi?Lei  Ling?Shi  Chengxuan?Tan  Daogong?Hu 《Environmental Geology》2004,45(4):560-566

The spatial database of landslides in Fengdu County of the reservoir region of the Three Gorges project (TGP) on the Yangtze River was compiled from a variety of different sources including field investigations on landslides, existing catalogues and archives on landslides, reports of meteorological events and human engineering activities that triggered slope failures. The major factors that are found to have affected the slope stabilities are outlined, and an assessment and zonation of landslide hazards of the region is made using an integrated information model, which is divided into destructive, disastrous, likely disastrous and essentially non-disastrous areas from the assessment of landslide hazards. The destructive and disastrous areas are respectively 1.9 and 13.8% of the total region, mostly being nearby townships, highways along the south bank of the Yangtze River and residential quarters along two flanks of the Yangtze River and its distributaries, that will impose direct impact to highway transportation and residential lives, and may effect to some degree the navigation of the Yangtze River, reservoir banks, and building of cities and towns.  相似文献   

INFLUENCE OF THE SURFACE AIR TEMPERATURE OVER ASIAN-PACIFIC REGION ON THE SUMMERTIME NORTHEASTERN ASIAN BLOCKING HIGH^*          下载免费PDF全文

CAO Jie  DONG Huilin  YAO Ping 《Acta Meteorologica Sinica》2004,18(4):455-466

Synthesis analysis and singular value decomposition (SVD) methods were used to study the impact of surface air temperature (SAT) over Asian-Pacific region on the summertime northeastern Asian blocking high (NABH) with NCEP/NCAR Reanalysis Data.The results showed that 500 hPa geopotential height and SAT fields over Asian-Pacific region shared the similar pattern of East Asian Pacific (EAP) wave train;there was steady remote response relationship between the EAP wave train in summer and the "+-+" pattern of tropical SAT in zonal direction from former winter to summer;there were two relative negative(positive) Walker circulations over the tropical Indian Ocean and Pacific when being more(less) summertime NABH. The influence of sea surface temperature anomaly (SSTA) on the summertime NABH was possibly as follows.The special distribution of SSTA in tropical zonal direction continuously forced the tropical convection and zonal circulation from former winter to summer,and led them to act anomaly.Finally the abnormal conditions were transported to middle-high latitudes through EAP wave train and yielded the advantageous or disadvantageous atmospheric circulation background for the summertime NABH.  相似文献   

基于双二次插值多项式的DEM传递误差模型   总被引：8，自引：4，他引：4  

王淑萍  姚红  郑海鹰  朱长青 《测绘科学技术学报》2006,23(1):33-35

基于函数插值方法,得出了基于不完全双二次插值多项式的规则格网数字高程模型(DEM)的表面表达模型,并推导了相应的传递误差公式.公式表明,不完全双二次多项式的DEM传递误差与双线性多项式的传递误差相同.但由于不完全双二次多项式的DEM表面建模误差低于线性多项式的DEM表面建模误差,因此基于不完全双二次多项式的DEM表面模型具有更高的精度.  相似文献   

Photosynthetic characteristics of dominant tree species and canopy in the broadleaved Korean pine forest of Changbai Mountains     

Wu Jiabing  Guan Dexin  Sun Xiaomin  Zhang Mi  Shi Tingting  Han Shijie  Jin Changjie 《中国科学D辑(英文版)》2006,49(2):89-98

Based on the light-photosynthesis response measurement at leaf level, combined with over-and under-canopy eddy covariance measurements, research on photosynthetic characteristics of single trees and forest canopy was conducted. The relationship between light intensity and photosynthetic rates for leaves and canopy can be well fitted by a non-rectangular hyperbola model. Mongolian oak presented a high light compensation point, L _cp (28 μmol·m^?2·s^?1), a light saturation point L _sp (>1800 μmol·m^?2·s^?1), and a maximal net photosynthetic rate P _max (9.96 μmol·m^?2·s^?1), which suggest that it is a typical heliophilous plant. Mono maple presented the highest apparent quantum efficiency α (0.066) but the lowest, L _cp (16 μmol·m^?2·s^?1), L _sp (≈800 μmol·m^?2·s^?1), and P _max (4.51 μmol·m^?2·s^?1), which suggest that it is heliophilous plant. Korean pine showed the lowest α value but a higher P _max, which suggest that it is a semi-heliophilous plant. At the canopy level, the values of both α and P _max approached the upper limit of reported values in temperate forests, while L _cp was within the lower limit. Canopy photosynthetic characteristics were well consistent with those of leaves. Both showed a high ability to photosynthesize. However, environmental stresses, especially high vapor pressure deficits, could significantly reduce the photosynthetic ability of leaves and canopy.  相似文献   

基于广义3S技术的森林资源经营管理系统建设   总被引：8，自引：0，他引：8  

冯仲科  臧淑英  姚山 《测绘工程》2006,15(2):1-6

针对我国森林资源经营管理处于比较粗放的水平,将现代测绘科学与林业相结合,构建基于广义3S技术的森林资源经营管理系统。  相似文献   

Automatic extraction of foreground objects from Mars images     

WANG Shuliang  LIU Chang  WU Shangru  NIE Qianqian  WANG Yongtao  ZENG Shi  ZHU Haifeng 《地球空间信息科学学报》2012,15(1)

  相似文献   

利用IKONOS立体像对提取DEM精度的实验   总被引：4，自引：1，他引：3  

丁辉  姚安强 《测绘科学》2012,(1):179-181

由于IKONOS不提供基于共线模型所需的卫星星历参数,而提供基于有理函数(RPC)的近似模型,因此点位精度和高程精度主要由RPC模型精度来决定。直接使用RPC模型对标准几何校正产品进行DEM提取,这种精度不能满足高精度制图的要求。本文讨论了基于IKONOS立体像对提取翠华山地区的DEM及其精度情况。为提高精度,采用高精度GPS仪(Mobile Mapper CX高程精度达亚米级)野外采集控制点,对RPC模型进行修正。对比分析结果表明DEM精度明显提高,仅需少量的控制点,DEM和正射影像均满足15∶000比例尺地形图和遥感平面制图要求。  相似文献   

电子签章技术在办公自动化系统中的应用     

肖伟  赵善仁  咸容禹  时泰卿 《国土资源信息化》2012,(3):55-58,41

电子签章技术是应用十分广泛的一种信息安全技术,其用来保证信息在传输过程中的真实性、完整性以及不可否认性。本文分析了办公自动化系统中存在的安全问题,在此基础上阐述了电子签章的概念、分类、实现原理以及其在办公自动化系统中应用的可行性和原则,并对系统的总体框架和功能进行了详细描述。  相似文献