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771.
基于小波和线矩的实孔径雷达图像与TM图像的匹配   总被引:3,自引:0,他引:3  
为了充分利用多源遥感信息,常常需要解决不同传感器图像之间的匹配问题。为此,本文初步探讨了一种基于小波边缘检测与线矩描述的实孔径雷达图像与TM图像的匹配算法。实验结果表明:如果搜索窗口内存在较丰富的特征,该算法可以获得满意的结果。  相似文献   
772.
The original structural design of this case study consisted of five basement floors and a 34‐story hotel tower in Kaohsiung, Taiwan. The construction started in 1993, and the erection of the entire steel frame and the pouring of concrete slabs up to the 26th floor were completed before 1996. However, construction of the original hotel was subsequently suspended for 10 years. Recently, this building has been retrofitted for residential purposes. Buckling restrained braces (BRBs) and eccentrically braced frames were incorporated into the seismic design of the new residential tower. This paper presents the seismic resisting structural system, seismic design criteria, full‐scale test results of one BRB member and the as‐built welded moment connections. Test results confirm that the two side web‐plate stiffening details can effectively improve the rotational capacity of welded moment connection. The paper also discusses the analytical models for simulating the experimental responses of the BRB members and the welded moment connections. Nonlinear response history analyses (NLRHA) indicate that the inelastic deformational demands of the original and the redesigned structures induced by the maximum considered earthquakes are less than those found in the seismic building codes or laboratory tests. This paper also proposes a ground motion scaling method considering multi‐mode effects for NLRHA of the example building. It is shown that the proposed scaling method worked well in reducing the scatter in estimated peak seismic demands. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
773.
2009年4月6日意大利拉奎拉(L'Aquila)地震快速矩张量解.   总被引:3,自引:1,他引:2  
刘超  许力生  陈运泰 《地震学报》2009,31(4):464-465
2009年4月6日1点32分42秒协调世界时(UTC),在意大利中部地区发生了MW6.4地震.作者利用矩张量快速反演技术,通过反演全球台网的宽频带P波波形得到了这次地震的矩张量解,并判断走向132deg;、倾角53deg;、滑动角——103deg;的节面是地震发生的断层面.   相似文献   
774.
肖诗云  许东 《地震学刊》2009,(6):668-675
根据混凝土单轴动力特性试验,引入了应变率的影响,对规范给出的混凝土应力一应变关系表达式进行了修正;针对只考虑混凝土的动态特性和既考虑混凝土的动态特性、也考虑钢筋的动态特性这两种情况,利用修正的表达式对钢筋混凝土柱的动态特性进行了数值分析。结果表明,混凝土的动态特性对于大偏心柱的承载力影响很小,但对于小偏心柱的极限承载力影响显著;钢筋的动态特性对大、小偏心柱的极限弯矩和极限曲率都有明显的影响。本文还分析了柱的极限弯矩、极限曲率和极限轴力随偏心距变化的规律。  相似文献   
775.
An Ms6.8 strong earthquake took place in Jiashi, Xinjiang on February 24 of 2003. The digital wave form data recorded in Kashi and Wushi stations are selected to inverse the moment tensor solutions for the strong earthquake and the moderate and small earthquakes before and after it ( 108 earthquakes in 2001 - 2004). 67 focal mechanism solutions have been calculated, and the results agree with those from Harvard University and USGS. The analysis reveals that before the strong earthquake, the moderate and small earthquake distribution was dispersed, and after the event the distribution was mainly concentrated around the strong earthquake. Before the strong earthquake, the seismic faults of the mid and small events had the character of strike-slip and normal faulting, and after the event, they exhibit strike-slip and thrust faulting. The region is dominated by near-NS horizontal compression from the southern block after the strong earthquake.  相似文献   
776.
A MS8.0 earthquake occurred in Wenchuan County, Sichuan Province, China, on May 12, 2008, and subsequently, numerous aftershocks followed. We obtained the moment tensor solutions and source time functions (STFs) for the Wenchuan earthquake and its seven larger aftershocks (MS5.0~6.0) by a new technique of moment tensor inversion using the broadband and long-period seismic waveform data from the Global Seismic Network (GSN). Firstly, the theoretical background and technical flow of the new technique was briefly introduced, and an aftershock of the Wenchuan earthquake sequence was employed to illustrate the real procedure for inverting the moment tensor; secondly, the moment tensor solutions and STFs of the eight events, including the main shock, were presented, and finally, the interpretation of the results was made. The agreement of our results with the GCMT results indicates the new approach is efficient and feasible. By using this approach, not only the moment tensor solution can be obtained but also the STF can be retrieved; the inverted STFs indicate that the source rupture process may be com-plicated even for the moderate earthquakes. The inverted focal mechanisms of the Wenchuan earthquake sequence show that the most of the aftershocks occurred in the main faults of the Longmenshan fault zone with predomi-nantly thrustingwith minor right-lateral strike-slip component, but some of them may have occurred in the sub-faults with strike-slip faulting in the vicinity of the main faults.  相似文献   
777.
王洪兴  王冠  唐辉明 《岩土力学》2006,27(Z1):725-728
为了更客观和科学地评价斜坡的稳定性,采用结构可靠度中的改进一次二阶矩法来分析斜坡的稳定性,同时采用新的、更适于计算机编程的求可靠指标解的迭代方法,对三峡库区赵家坡高切坡第二段稳定性分析标明:(1)潜在滑动面1可靠指标和破坏概率均满足允许风险水平,稳定性程度较高,只需进行表面防护即可;(2)潜在滑动面2可靠指标和破坏概率均不满足允许风险水平,需要进行整体加固并辅以坡面防护;(3)稳定性系数与可靠度分析结果有良好的一致性。  相似文献   
778.
We have determined approximate average rates of deformation in the Qinghai-Tibet plateau and its margins from the GPS data for last 10 years and the moment tensors from earthquakes between 1900 and 1999.We also determined the strain rate (seismic strain rate) associated with the seismic deformation using 254 Mw≥5.0 earthquakes,and estimated the shortening and extension rates for every block in the area as well.We also estimated the strain rate (geodetic strain rate)by 80 GPS sites' velocity vectors and analyzed characteristic of kinematics by two kinds of strain rates and discussed earthquake potential in the area.As a result,the deformation rates from seismic moment tensors and from GPS velocities are basically agreed with each other.It is feasible to analyze seismic risk by comparing geodetic strain rate with seismic strain rate based on the opinion that strain energy will be released through earthquake.It is concluded that there is no strong earthquake potential (>M7) in the Qinghai-Tibet plateau and its margins,but there is earthquake potential (>M5) in middle Tibet in a few years.  相似文献   
779.
利用鲜水河断裂带上各断层段的滑动速率 ,用震级—时间可预测模型估算了未来强震发震概率的 M0 值 ,并和其经验值进行了比较 ,结果证明了此计算方法的可靠性  相似文献   
780.
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