土-地铁隧道动力相互作用的大型振动台试验——试验结果分析   总被引：10，自引：3，他引：10  

陈国兴  庄海洋  杜修力  李亮  程绍革 《地震工程与工程振动》2007,27(1):164-170

在进行土-地铁隧道动力相互作用的大型振动台模型试验中,分别测出了模型地基的加速度反应、隧道结构的加速度反应、结构的侧向土压力反应和隧道结构的应变反应。本文首先对模型体系的加速度反应实测值进行整理,分析了模型地基的边界模拟效果、模型地基和隧道结构的加速度反应规律。其次,对模型隧道结构的应变实测结果进行了分析,给出了地铁区间隧道在水平向地震动作用下横截面的应变分布规律,分析了模型箱侧壁与地基土以及隧道结构与土体接触面上的动土压力实测结果及其反应的规律。最后,对试验中模型土的液化现象、地震裂缝和地下结构上浮等震害现象进行了描述。  相似文献   

On the Performance Evaluation of Pan-Sharpening Techniques   总被引：1，自引：0，他引：1  

Qian Du Younan  N.H. King  R. Shah  V.P. 《Geoscience and Remote Sensing Letters, IEEE》2007,4(4):518-522

The limitations of the currently existing pan-sharpening quality indices are analyzed: the absolute difference between pixel values, mean shifting, and dynamic range change is frequently used as spatial fidelity measurement, but they may not correlate well with the actual change of image content; and spectral angle is a widely used metric for spectral fidelity, but the spectral angle remains the same if two vectors are multiplied by two individual constants, which means the average spectral angle between two multispectal images is zero even if pixel vectors are multiplied by different constants. Therefore, it is important to evaluate the quality of a pan-sharpened image under a task of its practical use and to assess spectral fidelity in the context of an image. In this letter, three data analysis techniques in linear unmixing, detection, and classification are applied to evaluate spectral information within a spatial scene context. It is demonstrated that those old but simplest approaches, i.e., Brovey and multiplicative (or after straightforward adjustment) methods, can generally yield acceptable data analysis results. Thus, it is necessary to consider the tradeoff between computational complexity, actual improvement on application, and hardware implementation when developing a pan-sharpening method.  相似文献   

长距离跨海高程基准传递方法及精度   总被引：2，自引：0，他引：2  

李凤斌  柳光魁  王晓丽  汤少云  杜明成 《现代测绘》2007,30(2):7-8

大连市C级GPS控制网覆盖面积为1.7万km2.其中海域为4 700 km2,容有长山列岛的大小不等8个岛屿,8个网点分布在海岛,陆地与近海岛屿之间的距离为20-30 km;岛屿之间的距离为30-40 km;最大间距为120.5 km.本次研讨利用GPS定位技术结合重力资料所确定的小长山岛上网点高程与利用潮位观测法获得的相应网点高程比较,通过比较小长山GPS网点高程差值的方法研究长距离跨海高程基准传递可取的方法及精度.  相似文献   

用HV谱比法推测银川市区沉积层基底分布特征     

谢晓峰  赵伯明  柴炽章  王银  金涛  杜鹏  雷启云  孟广魁 《中国地震》2007,23(4):359-365

在缺乏其他资料的情况下,地脉动常常用做确定地震动对地表介质产生影响效应的简便手段。本文以银川市区为研究对象,根据地震勘探资料有目的的选取5条测线在银川市区进行地脉动观测,观测点共141个。用Nakamura提出的HV谱比法解析观测数据,在给定地下构造剪切波速度(VS)的基础上,由H/V比值曲线中的基本频率推测盆地深层地下构造。通过理论计算进一步验证了解析结果。结合前人地震勘探资料推测了银川市区脉动基本频率分布特征,并给出2D和3D银川市基底构造变化情况,对比分析表明,HV谱比法得到的脉动基本频率值可以反映银川盆地基底变化情况。  相似文献   

Anisotropic reverse-time migration for tilted TI media   总被引：1，自引：0，他引：1  

Xiang Du  John C. Bancroft  Larry R. Lines 《Geophysical Prospecting》2007,55(6):853-869

Seismic anisotropy in dipping shales results in imaging and positioning problems for underlying structures. We develop an anisotropic reverse‐time depth migration approach for P‐wave and SV‐wave seismic data in transversely isotropic (TI) media with a tilted axis of symmetry normal to bedding. Based on an accurate phase velocity formula and dispersion relationships for weak anisotropy, we derive the wave equation for P‐wave and SV‐wave propagation in tilted transversely isotropic (TTI) media. The accuracy of the P‐wave equation and the SV‐wave equation is analyzed and compared with other acoustic wave equations for TTI media. Using this analysis and the pseudo‐spectral method, we apply reverse‐time migration to numerical and physical‐model data. According to the comparison between the isotropic and anisotropic migration results, the anisotropic reverse‐time depth migration offers significant improvements in positioning and reflector continuity over those obtained using isotropic algorithms.  相似文献   

用VB和Fortran语言混合编程开发气象软件          下载免费PDF全文

杜文娟  李建东 《气象与环境科学》2007,30(4):88-90

阐述了利用VB和Fortran语言混合编程开发气象预报系统的两种方法,一种是利用VB的shell函数调用可执行文件法,另一种是利用VB调用Fortran生成的动态链接库法,并具体介绍了如何通过DLL实现VB 6.0和Fortran的接口,最终实现VB的可视化界面与Fortran强大数值计算能力相结合的新思路.  相似文献   

《气象与环境科学》2007年总目次          下载免费PDF全文

杜文娟  李建东 《气象与环境科学》2007,30(4):95-96

阐述了利用VB和Fortran语言混合编程开发气象预报系统的两种方法,一种是利用VB的shell函数调用可执行文件法,另一种是利用VB调用Fortran生成的动态链接库法,并具体介绍了如何通过DLL实现VB 6.0和Fortran的接口,最终实现VB的可视化界面与Fortran强大数值计算能力相结合的新思路.  相似文献   

气象温湿度因子与蚕病发生的初步探索     

焦金儿  吴雄伟  常素萍  刘强军  杜建华 《山西气象》2007,(1):9-11

蚕病是蚕农在养蚕过程中最顾忌的,2005年着重对养蚕过程中蚕病发生与温度、湿度问题进行定点对比试验。分析了温湿度与蚕病发生直接和间接的关系,提出了相应的生产调节措施。  相似文献   

Semidiurnal tides from the extended Canadian Middle Atmosphere Model (CMAM) and comparisons with TIMED Doppler interferometer (TIDI) and meteor radar observations     

J. Du  W.E. Ward  J. Oberheide  T. Nakamura  T. Tsuda 《Journal of Atmospheric and Solar》2007,69(17-18):2159

The extended Canadian Middle Atmosphere Model (extended CMAM) is a general circulation model, which extends from the surface to about 210 km. Spatial complex spectral analysis is applied to horizontal winds simulated by the extended CMAM to obtain semidiurnal tidal amplitudes and phases (from e5 to w5) in the mesosphere and lower thermosphere (MLT) region. The dominant w2 migrating component and the presence of eight nonmigrating tides (w3, w4, w5, e1, e2, e3, e4 and e5) in the mid-latitudes are identified. Components w1 and s0, which tend to maximize at high latitudes, will be discussed separately in a later paper. The migrating semidiurnal tide (w2) has amplitudes reaching over 20 m s⁻¹ for both zonal and meridional winds in the mid-latitude region. Its form compares well to the published results. The amplitudes of nonmigrating semidiurnal tides are non-negligible compared with the migrating semidiurnal tides. The amplitudes for w3 and e2 exceed 12 and 8 m s⁻¹, respectively.Comparisons are made with four nonmigrating semidiurnal components (w3, w4, e1 and e2) derived from the TIMED Doppler interferometer (TIDI) wind measurements between 85 and 105 km altitude and between 45°S and 45°N latitude. Overall, the basic CMAM and TIDI latitudinal structures of the amplitudes agree well and the agreement between the annual mean amplitudes varies with component. Relative to the TIDI results, the CMAM seasonal variations of w4 are in good agreement, of e2 are in reasonable agreement, of w3 are in partial agreement and of e1 are in poor agreement.The 11 semidiurnal components from the model are superimposed to generate the total semidiurnal winds at Jakarta (6°S, 106°E) and Kototabang (0°, 100°E) and are compared with measurements from two equatorial meteor radar stations at these sites. The relative contributions of components to the reconstructed amplitude vary from month to month. The CMAM reconstructions are generally larger than the radar results by a factor varying between one and two. The phases in the radar data are typically stationary with respect to height, whereas they generally decrease with height in the CMAM reconstruction.  相似文献   

雷电对通信系统电源设备的影响及防护     

杜昌雨 《山东气象》2007,27(2):68-69

介绍了雷电灾害的几种类型以及雷电对通信系统电源设备的危害，并提出了相应的雷电防护措施。  相似文献