基于广义的炮偏移方法实现地表多次波和一次波联合成像   总被引：4，自引：4，他引：0       下载免费PDF全文

郭书娟  李振春  仝兆岐  马方正  叶月明 《地球物理学报》2011,54(4):1098-1105

多次波是地下反射层的多次波反射,也蕴含了地下反射界面的信息,因此并不是绝对地只能被当做噪音来处理.为实现对地下构造的准确成像,本文基于广义概念上的炮偏移成像算法,对常规一次波偏移方法从用于向下延拓的上、下行场以及成像条件方面进行了改进,将同时含有表层多次波的炮记录与脉冲震源之和作为下行延拓的震源波场,将同时含有表层多次...  相似文献   

双参数混合正则化方法及在电导率反演成像中的应用          下载免费PDF全文

王文娟  Chris Farmer  John Ockendon  冯宝宾  曹俊兴  谭永基 《地球物理学报》2011,54(8):2154-2159

通过引入带有二阶正则算子的正则化项,建立了一种双参数混合正则化方法.为确定最佳正则化参数,这里主要应用L-曲线法、偏差原理和广义交叉校验准则的优化组合来确定.首先对理论模型进行了数值模拟,通过与截断奇异值分解法、共轭梯度法及标准Tikhonov正则化法的结果比较,表明该方法不仅精度高,而且对于数据的随机扰动具有稳定性....  相似文献   

Tall building vibration control using a TM‐MR damper assembly: Experimental results and implementation     

Rene Zemp  Juan C. de la Llera  Paul Roschke 《地震工程与结构动力学》2011,40(3):257-271

This paper summarizes the relevant results of the design, construction, testing, and implementation of a nominal 120 kN magnetorheological damper developed to control a free‐plan tall building in Santiago, Chile, equipped with two 160‐ton tuned masses. Cyclic as well as hybrid simulation tests were performed on the prototype damper. Global building responses using measured MR properties showed good correlation with analytical estimations. Also, a proposed physical controller for the MR damper was validated through hybrid and building pull‐back tests. Its performance is essentially equivalent to that of an LQR controller, but the information needed in its implementation is considerably less. Pull‐back tests of 10 cm amplitude were performed on one mass along the flexible edge of the building and its response controlled using the passive and controlled modes of the MR damper. The MR damper was capable of controlling the TM displacements very effectively, as well as the simulated building response for different ground motions and harmonic excitation. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Tall building vibration control using a TM‐MR damper assembly     

Rene Zemp  Juan C. de la Llera  José L. Almazán 《地震工程与结构动力学》2011,40(3):339-354

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VTI介质中准P波方程叠前逆时深度偏移   总被引：3，自引：0，他引：3       下载免费PDF全文

韩令贺  何兵寿  张会星 《地震学报》2011,33(2):209-218

根据具有垂直对称轴的横向各向同性（VTI）介质中的一阶准P波方程,导出了该方程在交错网格中逆时延拓的高阶有限差分格式,给出了其稳定性条件,采用完全匹配层吸收边界条件解决边界反射问题,分别应用下行波最大能量法和归一化互相关成像条件, 实现了VTI介质中准P波方程的叠前逆时深度偏移．各向异性Marmousi模型的试算结果表明,VTI介质准P波方程叠前逆时深度偏移算法不受地下构造倾角和介质横向速度变化的限制,对复杂模型具有良好的成像能力;应用归一化互相关成像条件能得到更好的成像效果．对比该模型的各向异性和各向同性逆时偏移剖面表明,在各向异性地区采集的纵波数据用各向异性偏移算法理论上能得到更好的成像结果．   相似文献   

MSCT对不同体重注射不同对比剂量在主动脉CTA中的探讨     

付传明  徐霖  陈伦刚  周选民  龚晓虹  陈文  吴德红 《CT理论与应用研究》2011,20(2):251-258

目的:探讨64层螺旋CT对不同体重注射不同对比剂量在主动脉血管成像中的应用效果.方法:60例临床可疑主动脉病变患者,知情同意后根据不同体重分为A、B、C三组,每组20例.A组:体重在75kg以上注射75mL对比剂+25mL生理盐水;B组:体重在60～75kg之间注射60mL对比剂+40 mL生理盐水;C组:体重在60k...  相似文献   

河流相储层特征及识别:一个老河口油田的实例分析(英文)   总被引：4，自引：1，他引：3  

张军华  刘振  朱博华  冯德永  张明振  张学芳 《应用地球物理》2011,8(3):181-188

河流相储层是一种重要的储层类型,寻找河道砂体是油气勘探的一项重要工作。但是河道变迁比较频繁,叠置比较严重,加之地震资料本身信噪比和分辨率的限制,河流相储层的精细描述至今仍存在一定的困难。本文以胜利油田老河口三维工区为例,首先研究了本区河流相储层的基本特征,发现该类储层剖面上呈强相位、切片上连续性好和频谱上呈低频特征;通过颜色处理和地震精细解释,发现本区河流相储层存在类串珠状特征,为了验证这一观测结果,我们用正演模拟分析了其形成机理,为在类似工区识别此类古河道找到了新的途径;应用多属性融合和RGB显示技术,河道下切特征更加明显,很好地彰显了河道结构特征,提高了河道识别能力;最后,我们研究并开发了多子波检测技术,检测出更多河流相弱反射信息。  相似文献   

Imaging spectroscopy in soil-water based site suitability assessment for artificial regeneration to Scots pine     

Maarit Middleton  Paavo Nrhi  Raimo Sutinen 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(3):287-297

In a humid northern boreal climate, the success rate of artificial regeneration to Scots pine (Pinus sylvestris L.) can be improved by including a soil water content (SWC) based assessment of site suitability in the reforestation planning process. This paper introduces an application of airborne visible-near-infrared imaging spectroscopic data to identify suitable subregions of forest compartments for the low SWC-tolerant Scots pine. The spatial patterns of understorey plant species communities, recorded by the AISA (Airborne Imaging Spectrometer for Applications) sensor, were demonstrated to be dependant on the underlying SWC. According to the nonmetric multidimensional scaling and correlation results twelve understorey species were found to be most abundant on sites with high soil SWCs. The abundance of bare soil, rocks and abundance of more than ten species indicated low soil SWCs. The spatial patterns of understorey are attributed to time-stability of the underlying SWC patterns. A supervised artificial neural network (radial basis functional link network, probabilistic neural network) approach was taken to classify AISA imaging spectrometer data with dielectric (as a measure volumetric SWC) ground referencing into regimes suitable and unsuitable for Scots pine. The accuracy assessment with receiver operating characteristics curves demonstrated a maximum of 74.1% area under the curve values which indicated moderate success of the NN modelling. The results signified the importance of the training set’s quality, adequate quantity (>2.43 points/ha) and NN algorithm selection over the NN algorithm training parameter optimization to perfection. This methodology for the analysis of site suitability of Scots pine can be recommended, especially when artificial regeneration of former mixed wood Norway spruce (Picea abies L. Karst) - downy birch (Betula pubenscens Ehrh.) stands is being considered, so that artificially regenerated areas to Scots pine can be optimized for forestry purposes.  相似文献   

多普勒雷达降水反演及其与改进的区域气候模式RIEMS的同化研究     

吴明光  陈泰生  檀姗姗  骆骐  闾国年  盛业华 《测绘学报》2011,40(5):0-0

本博士论文在前人构建的陆面水文过程模型TOPX和区域气候模式RIEMS的耦合模式的框架基础上,针对耦合模式中RIEMS对降水和蒸散发的模拟精度较低,RIEMS和TOPX模式之间尺度不匹配等几个核心问题进行了深入细致的研究:对天气雷达资料的定量估测降水方面的研究获得了对沂沭河流域最佳的Z-R关系,并通过雷达雨量计联合校正法得到较高精度的面降雨量;采用集合卡尔曼滤波同化算法对雷达反演的面雨量及区域气候模式RIEMS的降水输出进行了数据同化方案研究,获得了更好的降水模拟效果;在RIEMS和水文模型TOPX构成的耦合模型中加入同化方案,实现了流域降水的实例模拟研究,结果表明使用同化方案明显改善了水文模拟效果。  相似文献   

基于GIS的省级地质灾害数据库设计与实现   总被引：2，自引：0，他引：2  

彭颖霞  何贞铭  占辽芳  廖野翔  李若瑶 《测绘与空间地理信息》2011,34(3):157-161

为了进行地质灾害区划研究,作者在对国内外地质灾害研究现状进行分析的基础上,提出了利用GIS强大的空间分析和快速的图文互访功能来管理分析地质灾害数据,并从数据共享的角度提出建立省级地质灾害数据库.文章从数据库的概念性设计、逻辑设计和数据库实体建设等方面详细介绍了省级地质灾害数据库的设计过程:从属性数据库建设、图形数据库建...  相似文献