Offset dependent amplitudes: Fault curvature effects and dip move-out corrections

Equations have been presented previously which predict that reflector curvature can affect significantly seismic reflection amplitudes at both zero and nonzero source-receiver offsets. Here the fact that faults are generally concave-upward is used to examine the curvature effect for compaction-driven faults which the sediments have both exponential and logarithmic porosity decreases with increasing depth.The curvature effect is generally larger over upwardly concave reflectors where amplitudes can either increase with offset (exposed focus) or decrease with offset (buried focus). The magnitude of the effect depends on the ratio between the depth to the structure and the radius of curvature of the structure. A phase change of 90° also occurs at a critical offset in the case of an exposed focus concave-upward reflector, with decreasing amplitude at offsets larger than the critical value. Dip move-out (DMO) dominantly removes the amplitude variation with offset due to curvature. These results suggest that when looking for amplitude variations with offset in a fault prospect, DMO should be applied as a preprocessing step. Compaction-driven faults have an exposed focus and, for an exponential variation of porosity with depth, there is a maximum curvature effect at a depth roughly the same as the scaling depth for the porosity. Logarithmic porosity with depth variations suggest a continued increase in the curvature effect of faults with increasing depth, to a maximum amplitude increase of about 35% relative to a plane interface.     

开敞水域中航槽流场的数值模拟

建立了一个模拟开敞水域中航槽流场的平面二维数学模型.利用该模型计算得到的流速分布与袁美琦、李安中等人试验值相吻合,并计算了相当于天然情况下(各种水深、挖深比及航槽与水流的不同交角)的流场,得到了各种航槽与水流交角、不同挖深比的航槽流速折减系数变化规律图,及各种航槽与水流交角、不同挖深比的航槽中流向与航槽轴线交角的变化规律图,为开敞水域中航槽选线设计提供了依据.     

用数字测高仪漂移测量研究电离层声重波扰动

数字测高仪Digisonde中的漂移测量,常用来研究小尺度电离层扰动,如电离层小不均匀体的漂移。文中提出一种新的分析方法,利用漂移测量数据中多普勒频移和到达角参量的最大熵动态功率谱,估算声重波一类大尺度电离层扰动的水平传播速度和传播方向。作为实例,研究了Millstone Hill测高仪站的漂移观测资料,并对处理结果进行了初步分析。分析结果表明,从数字测高仪漂移测量数据中,可有效地提取声重波一类大尺度电离层扰动的传播参量,在电离层动力过程的研究中很有意义。     

国土卫星影像应用研究——京津唐地区资源与环境综合分析

本文利用国土卫星影像就京津唐地区的自然资源与环境调查进行了多学科综合应用和高层次专题制图的研究。在研究中,对影像的基本特性、质量和使用的技术指标作了较系统的分析,并按其精度、使用程度和效果等提出了评价。同时对国土卫星像片的几何配准,运用多项式与有限元法相结合的原理,进行了计算机和光学处理的对比研究。 本区资源与环境的遥感调查应用,主要是运用遥感地学原理,分析水文下垫面要素,划分水文环境类型,计算其产水量;分析非农业用地与总土地及其它用地的比例关系,探索土地利用类型结构的地域差异规律;农业低产地环境及其数量、质量特征的研究;综合调查森林资源,包括宜林地的生态环境、立地条件及宜林树种的生态与经济特性;以及以北京为中心的京津唐旅游圈及功能分区,矿产资源的赋存机制,区域地壳稳定性及区内近一万年来的自然环境的演化规律及其与国土整治、规划和城镇建设的关系等进行了多元综合研究。同时编制了一套高层次专题图件,并量算了各种资源数据。     

头部冠状位CT可调角度扫描架的研究

本文研究了头部冠状位ＣＴ可调角度扫描架的制做和应用。为了解决临床工作中头部冠状位ＣＴ扫描技术中存在的摆位困难，病人体位不舒适而移动所产生的定位不准确、图像不清晰、伪影等问题，着重介绍头部冠状位ＣＴ可调角度扫描架的固定作用和可调角度的研究．     

水压致裂煤层裂缝发育特点的研究

本文对煤岩基本力学性质、煤层水压致裂缝形成条件、裂缝形态以及裂缝开裂角方位等基本理论进行了研究与探讨，通过大量煤岩力学性质测试，证实了试验区目的层煤岩弹性模量低，泊松比较高，脆性大，易破碎，易压缩。文章还得出了目的层煤岩Ｍｏｈｒ断裂准则二次抛物线型包络线，煤层水压致裂裂缝形式判断，裂缝开裂角方位的计算公式以及有关结论。     

温纳偏置电测深法压制表层电性不均匀体影响的研究

巷道底板浮煤等电性不均匀体及厚度变化是造成煤矿井下电测深曲线畸变的主要因素。通过模型实验研究了温纳偏置电测保法压制浮煤等表层电性不均匀体影响的能力。用感度分析法讨论了表层电性不均匀体产生地电干扰的机制。实测结果表明，该方法改善了电测深曲线质量，有效地提高了电测深法地质应用效果。     

The influence of weathering on the geotechnical properties and slope angles of mudstone in the Mineoka earth-slide area,Japan

Three active earth-slide slopes of Tertiary mudstone were investigated: Slope 1 has an angle of 17 ?4°, Slope 2 of 12.9°, and Slope 3 of 11.6°. Infinite slope analysis indicated that the instability of these three slopes can be well explained by using the residual strength parameters of earth-slide soils near the sliding surface in conjunction with the highest ground water table. The residual angle of shearing resistance, ø'_r, plays an important role in the determination of slope angle because it differs greatly among slopes. Mineralogical studies and X-ray diffraction analyses were performed for the clay minerals included in the slope material. The results showed that illite and chlorite were found in Slope 1, and also in Slopes 2 and 3 together with interstratified illite/montmorillonite and montmorillonite. The degree of weathering is progressive in order of Slopes 1, 2 and 3. The alteration of clay minerals by weathering causes the reduction in ø'_r -values, i.e., 19.4° in Slope 1 (steep, less weathered) and 12.1-9.2° in Slopes 2 and 3 (gentle, much more weathered). This result indicates that the degree of weathering has a great influence on the value of ø'_r, which in turn determines the slope angle.