Using three-dimensional discrete spherical Fourier descriptors based on surface curvature voxels for pollen particle recognition     

谢永华  Michael OhEigeartaigh 《海洋学报(英文版)》2010,29(11)

  相似文献   

改进的最小曲率迭代法在重力剖面数据插值中的应用     

朱文武  彭军还  高艳龙  李方舟  贾玥 《大地测量与地球动力学》2019,39(8):810-812

基于将约束点也作为待解算结点的思想,对传统最小曲率迭代法进行改进。改进后的方法在待解算结点周围存在约束点时,避免了根据约束点与待解算结点之间的不同关系需要进行分类推导的复杂过程,同时也避免了因使用泰勒展开式进行分解造成的精度损失,提高了解算精度。  相似文献   

���ú����ݶ�������ǿ�ų��������񻯷���     

�ų�  ��ѷ  ���� 《大地测量与地球动力学》2014,34(5):164-167

??????????????????????????????????????С?????????????????????????С?????????????????????????????????????????????????????????????????????????????????Ч????  相似文献   

离散位场数据格网化方法探讨   总被引：1，自引：0，他引：1  

方杨 《测绘信息与工程》2009,34(6):46-48

针对均衡异常数据,比较分析了连续曲率张力样条方法、最小曲率方法和Shepard方法,结果表明张力样条方法解的全局效果较好。  相似文献   

川东南长宁地区地震活动及b值演化特征     

解孟雨  孟令媛 《中国地震》2021,37(2):494-507

利用全国统一目录和流动台站目录,研究了四川盆地东南部长宁地区的地震活动特征和b值的空间分布特征.研究结果显示,长宁地区的地震活动在时间上呈现明显的分段特征,地震活动在2015年后明显增强;在空间上,长宁地区的地震活动主要集中在以28.3°N为界限的南、北2个地区,对于这2个区域的b值演化,计算结果显示出不同的分段特征....  相似文献   

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

I. Lerche 《Pure and Applied Geophysics》1994,143(4):537-562

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.  相似文献   

Strain segmentation and lateral membrane deformation rate of the subducted Ryukyu slab     

LingYun  Chiao 《Island Arc》1993,2(2):94-103

Abstract Focal mechanisms of intermediate-depth earthquakes within the subducted Ryukyu slab indicate a systematic pattern of down-dip extension in the northern part under Kyushu. These mechanisms switch rapidly around the Tokara channel to down-dip compression in the southern part toward Taiwan. This intriguing pattern of strain segmentation, together with the differences between the slab geometry of the northern and southern parts, has raised the question of whether stress segmentation, as defined possibly by a tear fault, might exist in the slab. However the Ryukyu trench has a concave oceanward shape in the northern segment while it is convex in the southern oceanward part toward Taiwan. The inflection zone is located around the Tokara channel. The concept of Gaussian curvature of a curved surface suggests that the along-arc variation of the geometric configuration of a subducted slab is related to the shape of the trench. This is in order to accommodate the lateral membrane deformation of the slab as the oceanic lithosphere subducts from a spherical shell to the geometry delineated by the Wadati-Benioff zone. The membrane deformation regime of the subducted Ryukyu slab and its relation with the trench geometry was examined by assuming that the subduction be modelled by the flow field of a thin viscous sheet. A projection operator was utilized to compute the membrane strain-rate tensor of an arbitrary non-Euclidean surface. Numerical experiments indicated that the northern segment of the slab was dominated by lateral compression and down-dip extension and the southern part by lateral extension and down-dip compression. This transition is sharply located near the Tokara channel. These patterns were compatible with what had been observed from studies of focal mechanisms, suggesting that the strain segmentation might be controlled, at least in part, by the lateral membrane deformation within the slab due to the trench shape in this subduction zone. The slab geometry was predicted by minimizing the integrated total dissipation power; this revealed distinct features that were consistent with observations. This implies that the slab geometry may also be affected by the membrane deformation in a systematic fashion.  相似文献   

基于抗震性态的设防标准研究   总被引：11，自引：0，他引：11       下载免费PDF全文

谢礼立  马玉宏 《地震学报》2002,24(2):200-209

以基于性态的抗震设计为出发点,并以我国为例,针对目前国内外抗震设防标准的若干问题和不足,提出了基于性态抗震设计的三环节抗震设防方法．将现有的设防内容改为确定结构的抗震设计类别、确定设计烈度或设计地震动参数、确定建筑的重要性等级３个方面,并分别在每一方面进行具体深入的研究,从而形成了一套完整的基于性态的抗震设防标准确定的原则、方法和框架,可以直接用来编制规范供抗震设计使用．   相似文献   

李口集区块煤储层地质条件及煤层气采收率     

申建 秦勇傅雪海  吴财芳何也刘正  巫修平 《中国煤田地质》2007,19(5):25-27

基于煤田勘探资料和矿井实际观测结果,结合测试分析和数值计算,对平顶山矿区李口集区块煤储层地质条件进行了研究。结果表明：区块内主煤层的煤体结构破坏严重,小型裂隙发育但连通性较差,含气量中等且属于低压煤储层,煤层气采收率偏低,地面原位开采的难度较大。为此,建议该区块的煤层气开发以矿井抽采为主,并在煤矿采动带和采空区辅以合理的地面抽采工程。  相似文献   

Analysis of Error Caused by Replacing Spherical Shell with an Elastic Plate Model in Studying Bending Deformation of the Lithosphere     

Wu Hongling Institute of Geomechanics  Chinese Academy of Geological Sciences  Beijing Wang Ren Center for Geodynamics Research  Peking University  Beijing 《中国地质大学学报(英文版)》1998,9(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＶｅｎｉｎｇＭｅｉｎｅｓｚ（１９４１）ｕｓｅｄｅａｒｌｉｅｒａｎａｐｐｒｏｘｉｍａｔｅｓｏｌｕ－ｔｉｏｎｆｏｒｔｈｅｅｑｕａｔｉｏｎｏｆｂｅｎｄｉｎｇｏｆｅｌａｓｔｉｃｔｈｉｎｐｌａｔｅｓｔｏｃａｌｃｕ－ｌａｔｅｔｈｅｖａｒｉ...  相似文献