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91.
设计了一种地震参数计算与数据传输程序,能够通过交互方式自动完成mb、mB、MS7、MS、ML五个震级及其他相关地震参数的计算,自动生成大震速报文件,直接连接PCU速报。不仅适用于数字地震仪同时也可以用于模拟仪器(如DD—1,DK—1)解决了SSB大震速报软件数据不易改动、容易出错、速度慢等问题。同时也完善了SSDP软件参数计算功能,提高了数字测震台的效能和速报水平,充分发挥了数字地震仪的优越性。  相似文献   
92.
Introduction The MS=8.1 earthquake occurred in west of the Kunlun Pass on November 14, 2001. It is the greatest earthquake occurred in China since the last half of the century and is an important event in recent seismic history of China. Some specialists consider that the earthquake occurred in the area where the earthquake monitoring capability is lowest in Chinese mainland; no striking precursory seismicity was found. The study on the precursory seismicity before the earthquake has not b…  相似文献   
93.
This paper proposes a simple lattice model for collapse analysis of RC bridges subjected to earthquakes by using the extended distinct element method (EDEM). In the model, a concrete element consists of lumped masses connected to one another by springs, and a reinforcement bar is represented by a discrete model or an integrated model. The proposed lattice model is simple but its parameters are reasonably defined. It has fewer element nodes and connecting springs, which will be of benefit by shortening the CPU time. The processes to determine the initial stiffness of concrete and steel springs, the parameters of the constitutive model and the fracture criteria for springs are described. A re‐contact spring model is also proposed to simulate the re‐contact of the concrete after fracture of springs; and a general grid searching method is used to decrease the CPU time for judging re‐contact after fracture. The lattice model is assessed by numerical simulations and experiments. As an application, a damaged single‐column pier subjected to the Kobe Earthquake in 1995 is analysed by EDEM with the proposed model. The simulation results indicate that the proposed model predicts well qualitatively the collapse process of RC bridges. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
94.
利用MATLAB实现图像处理与分析   总被引:1,自引:0,他引:1  
本文通过对图像的均衡操作、二值图像的处理、小波去噪等实例,介绍了MATLAB进行图像处理和分析的实用方法与技巧,它对各种软钉包、进行图像处理和分析等,提供了高效便捷的方法。  相似文献   
95.
Based on field analysis of fault-slip data from different rock units of the Cretaceous basins along the middle part of the Tan-Lu fault zone (Shandong Province, eastern China), we document polyphase tectonic stress fields and address the changes in sense of motion of the Tan-Lu fault zone during the Cretaceous. The Cretaceous deformation history of the Tan-Lu fault zone can be divided into four main stages. The first stage, during the earliest Cretaceous, was dominated by N-S extension responsible for the formation of the Jiaolai basin. We interpret this extension to be related to dextral strike-slip pull-apart opening guided by the Tan-Lu fault zone. The second stage, during the middle Early Cretaceous, was overwhelmingly rift-dominated and characterized by widespread silicic to intermediate volcanism, normal faulting and basin subsidence. It was at this stage that the Tan-Lu-parallel Yi-Shu Rift was initiated by E-W to WNW-ESE extension. The tectonic regime then changed during the late Early Cretaceous to NW-SE-oriented transpression, causing inversion of the Early Cretaceous rift basin and sinistral slip along the Tan-Lu fault zone. During the Late Cretaceous, dextral activation of the Tan-Lu fault zone resulted in pull-apart opening of the Zhucheng basin, which was subsequently deformed by NE-SW compression. This deformation chronology of the Tan-Lu fault zone and the associated Cretaceous basins allow us to constrain the regional kinematic models as related to subduction along the eastern margin of Asia, or related to collision in the Tibet region.  相似文献   
96.
自然与农田状态下照度计测光的偏差分析   总被引:2,自引:0,他引:2       下载免费PDF全文
王谦  陈景玲  吴明作  董中强 《气象》2003,29(3):8-11
根据色度基本原理,推导并计算了不同天气类型下照度的换算因数,并在不同天气类型下,对自然光和小麦群体不同高度透光情况进行了测定,将照度计实测照度换算出的辐射强度与实测辐射强度进行对比。结果表明:①前两种照度计可以在1、2级日光状况下用于太阳辐射测定而在3、4级日光状况下误差较大。②在作物田中,实测照度换算为辐射光量子数时,内活动面偏差比在0.2左右,而外活动面因光斑阴影作用,偏差较大,实测时应增加重复。  相似文献   
97.
Along the meridian of 105°E, the Chinese region are divided into two parts, east and west. The results show that in the east part of China the temperate extratropical belt, the warm extratropical belt,and the northern subtropical belt shift northward significantly, whereas the middle subtropical belt and the southern subtropical belt have less or no change. As for the northern subtropical belt, the maximal northward shift can reach 3.7 degrees of latitude. As for the warm extratropical belt, along the meridian of 120°-125°E, the maximal northward shift can reach 3-4 degrees. In the west part of China, each climatic belt changes little. Only in the Xinjiang area are the significant northward shifts. Correspondingly, it is found that in the last 50 years the traditional seasons have changed. For Beijing, Hailar, and Lanzhou, in general, summer becomes longer and winter shorter over the last 50 years. Summer begins early and ends late with respect to early 1950s. Contrary to the summer, winter begins la  相似文献   
98.
This study provides new evidence for the feedback effects of vegetation cover on summer precipitation in different regions of China by calculating immediate (same season), and one-and two-season lagged correlations between the normalized difference vegetation index (NDVI) and summer precipitation. The results show that the correlation coefficients between NDVI in spring and the previous winter and precipitation in summer are positive in most regions of China, and they show significant difference between regions. The stronger one-and two-season lagged correlations occur in the eastern arid/semi-arid region, Central China,and Southwest China out of the eight climatic regions of China, and this implies that vegetation cover change has more sensitive feedback effects on summer precipitation in the three regions. The three regions are defined as sensitive regions. Spatial analyses of correlations between spring NDVI averaged over each sensitive region and summer precipitation of 160 stations suggest that the vegetation cover strongly affects summer precipitation not only over the sensitive region itself but also over other regions, especially the downstream region.  相似文献   
99.
昆仑山口西8.1级地震前青藏块体边界断层异常活动   总被引:5,自引:0,他引:5  
范燕  车兆宏 《地震》2003,23(2):121-126
系统分析了青藏块体边界断层的形变资料,研究了断层活动的动态过程及空间分布。结果表明,昆仑山口西8.1级地震前孕震影响范围达到青藏块体的周边地区;发震断层所在的构造带震前断层活动最为剧烈;加强对构造块体断层整体活动的宏观动态比较和分析,有助于判定未来强震发生的危险地段;震后应力将转移并集中到西秦岭构造带及其邻近地区。  相似文献   
100.
董守玉  万迪坤 《地震研究》1997,20(2):178-184
“平面图形演化方法”是利用无量刚的异常信息量来反映震前异常空间分布及其随时间的演化,从而预报发震时间和地点的一种方法,这种方法μ值等值线图法,μ值异常平面图法组成,它是通过绘制不同的时间上述二种平面图,通过分析水位,水化异常于震前在时间上,空间上的演化规律,寻找μ值异常集中区或高值区,异常丛集图像分布区,条带图像分布带及条带交叉图像地区,并考虑异常分布图像与活动构造带和地震带的关系,从而对强震发生  相似文献   
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