不同土壤有机质组分对憎水有机物的吸附机理研究   总被引：15，自引：2，他引：15  

陈迪云  黄伟林 《地球化学》2003,32(4):368-374

采用完全混合一步平衡反应实验方法，选择菲、萘、三氯苯和二甲苯作为憎水有机物(HOCs)的探针，研究了它们在土壤及其中的胡敏酸、胡敏素等有机质组分中的等温平衡吸附行为，探讨了非线性吸附的机制。结果表明，HOCs在水与土壤体系中表现为非线性吸附，其非线性的吸附行为主要受到土壤有机质(SOMs)的控制。SOMs具有高度不均匀的性质，HOCs表现出非线性吸附行为是其在不同的SOMs相扩散转移以及在相对聚结的胡敏素和“黑炭”的表面吸附的结果。  相似文献   

一个剪切位移公式的几何证明     

刘瑞珣  吕古贤  王世锋  夏林 《高校地质学报》2003,9(1):123-127

剪切位移测量公式是研究韧性剪切带中的常用公式，但该公式的代数推导较为复杂，难以被构造地质学研究领域的人们所接受，作者提出了更直观和易董剪切位移测公式的几何证明法。  相似文献   

基于IKONOS的植被提取前的校正   总被引：2，自引：0，他引：2  

颜梅春  张友静  鲍艳松 《测绘信息与工程》2004,29(3):34-36

探讨了植被信息提取中的图像预处理,重点是阴影区的提取和校正,实验证明,具有较好的效果.  相似文献   

航空影像多直角平顶房屋的半自动提取   总被引：7，自引：0，他引：7  

程曦冉  张剑清  张祖勋 《武汉大学学报(信息科学版)》2004,29(12):1097-1100

提出了一种从数字航空立体像对半自动提取多直角平顶房屋的方法。试验表明 ,本方法能提高提取建筑物的精度 ,其定位精度较高。  相似文献   

地震动的空间变异性对多支承结构的影响   总被引：5，自引：0，他引：5  

王航  杨庆山 《世界地震工程》2004,20(1):54-69

导致地震动空间变异性的原因主要在于：几何不相关性效应、行波效应、局部场地条件效应。利用时程分析的方法分析了单跨框架结构和美国Las Vegas市区内某24跨立交桥的简化模型，对地震动空间变异性三个主要因素的单独影响、综合影响分别进行了系统分析。结果表明地震动的空间变异性改变了一致激励下结构的动力反应，并且引入了一致激励情况所不存在的拟静力反应，对结构的总反应具有很大的影响。与较激励的情况相比，结构的反应可能增大，也可能减小，这依赖于结构上截面位置、场地条件和所采用的地震动时程样本。  相似文献   

全数字摄影测量系统作业方法分析   总被引：3，自引：0，他引：3  

林美妹 《福建地质》2002,21(4):235-240

介绍全数字摄影测量的工作流程，分析航空像片的扫描数字化质量对内业的精度影响，探讨全数字摄影测量内业作业过程各个环节的数字几何关系和误差影响，比较不同地形地貌条件下生成数字高程模型DEM，数字正射影像图DOM的作业流程。  相似文献   

SAR影像几何校正   总被引：21，自引：5，他引：21  

张永红  林宗坚  张继贤  甘梦龙 《测绘学报》2002,31(2):134-138

SAR影像的几何校正是阻碍其应用的瓶颈问题，目前所用的方法都有其局限性。介绍描述SAR构像几何的坐标系统及距离－多普勒方程，同时，介绍卫星轨道及描述卫星轨道的参数。为提高几何校正的精度，提出一种由几个离散点的值内插整个弧段上卫星状态向量的轨道模拟算法。在此基础上，给出利用DEM进行SAR影像几何校正的方法。该方法以时间参数为自变量，迭代解算距离－多普勒方程，计算DEM中点每一点对应的影像坐标，最后进行了实验与讨论。  相似文献   

钢筋混凝土带暗支撑低矮剪力墙非线性有限元分析   总被引：10，自引：1，他引：10  

董宏英  曹万林  霍达  张建伟 《地震工程与工程振动》2002,22(5):66-70

在试验研究基础上，采用ANSYS有限元分析程序，对钢筋混凝土带暗支撑低矮剪力墙在单向加载下的性能作了非线性分析，从理论计算角度进一步了解其在水平荷载作用下的开裂，变形及破坏全过程，有限元分析与试验结果符合较好。  相似文献   

THE CORRELATION BETWEEN GEOMETRIC FEATURE OF CO-SEISMIC RUPTURE AND CO-SEISMIC DISPLACEMENT          下载免费PDF全文

HAO Hai-jian  HE Hong-lin  WEI Zhan-yu 《地震地质》1979,42(1):109-124

The existence of asperity has been confirmed by heterogeneously distributed seismic activities along the slipping surface associated with recent huge earthquakes, such as the M8.0 2008 Wenchuan earthquake and M9.0 2011 Tohoku-Oki earthquake. The location of asperity embedded in the seismogenic depth always corresponds to the area of high value of the co-seismic displacement and stress drop where the elastic energy is accumulated during the inter-seismic periods. Fault segmentation is an essential step for seismic hazard assessment. So far, the fault trace is dominantly segmented by considering its geometric features, such as bends and steps. But the connection between the asperity and geometric feature of the slipping surface is under dispute. Research on correlation between geometric feature of surface rupture and co-seismic displacement is of great significance to understand the relationship of seismicity distribution to geometric morphology of sliding surface. To scrutinize the correlation between the geometric feature and co-seismic displacement, we compiled 28 earthquake cases among which there are 19 strike-slip events and 9 dip-slip events. These cases are mainly collected from the published investigation reports and research papers after the earthquake occurred. All the earthquakes' magnitude is between M_W5.4~8.1 except for the M_W5.4 Ernablla earthquake. The range of the rupture length lies between 4.5~426km. Each case contains surface rupture trace mapped in detail with corresponding distribution of co-seismic displacement, but the rupture maps vary in projected coordinate system. So, in order to obtain uniform vector graphics for the following data processing, firstly, vectorization of the surface rupture traces associated with each case should be conducted, and secondly, the vector graphics are transformed into identical geographic coordinate system, i.e. WGS1984-UTM projected coordinate system, and detrended to adjust its fitted trend line into horizontal orientation. The geometric features of surface rupture trace are characterized from three aspects, i.e. strike change, step and roughness. Previous studies about the rupture geometry always describe the characteristics from the whole trace length, consequently, the interior change of the geometric characteristics of the rupture is overlooked. In order to solve this problem, a technique of moving window with a specified window size and moving step is performed to quantify the change of feature values along the fault strike. The selected window size would directly affect the quantified result of the geometric feature. There are two contrary effects, large window size would neglect the detail characteristics of the trace, and small window size would split the continuity of the target object and increase the noise component. So we tested a set of sizes on the Gobi-Altay case to select a proper value and choose 1/25 of the whole rupture length as a proper scaling. Here, we utilize the included angle value of the fitted line in the adjoining windows, Coefficient of variation and the intercept value of the PSD(Power Spectra Density)for characterizing the change of strike, step size and roughness. The rupture trace is extracted within every moving window to calculate the aforementioned feature values. Then we can obtain three sets of data from every rupture trace. The co-seismic displacement is averaged in piecewise with uniform interval and moving step along the fault strike. Then, the correlations between three kinds of feature value and the co-seismic displacement are calculated respectively, as well as the P-value of correlation coefficient significant test. We divided cases into two groups according to the slip mode, i.e. strike-slip group and dip-slip group, and contrast their results. In the correlation result list, there is an apparent discrepancy in correlation values between the two groups. The values of the strike-slip group mostly show negative, which indicates that geometric feature of the rupture trace is in inverse proportion to the displacement. In dip-slip group, the values distribute around zero, which suggests the geometric features is irrelevant to the displacement. Through the analysis of the correlation between the surface rupture and co-seismic displacement, the following conclusions can be reached:1)In comparison with the dip-slip earthquake type, the characteristics of surface rupture of strike-slip earthquakes have a higher-level of correlation with the distribution of the co-seismic displacement, which suggests that the geometric features of strike-slip active faults may have a higher reference value in the fault-segmentation research than the dip-slip type; 2)In most strike-slip events, there is a negative correlation between the geometric features and the co-seismic displacement, which implicates that the higher the feature values of the steps, strike change and roughness, the lower the corresponding co-seismic displacement is; 3)Among the three quantified features of the surface rupture trace, the ranking of relevancy between them and the co-seismic displacement is:step size > strike change > roughness.  相似文献   

高分辨率卫星遥感影像的姿态角常差检校   总被引：2，自引：0，他引：2  

袁修孝  余俊鹏 《测绘学报》2008,37(1):0-113

简要叙述高分辨率卫星遥感影像的严格几何模型,建立影像姿态角常差检校模型。通过对来自SPOT-5, QuickBird两种不同卫星遥感影像的试验,验证影像姿态角常差的存在。利用单个控制点检校出的常差值对角元素进行补偿后,明显提高卫星遥感影像的对地目标定位精度,目标点平面位置可达到4 pixels的精度水平。  相似文献