排序方式： 共有73条查询结果，搜索用时 31 毫秒
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根据自动站地温数据采集原理、工作流程,对产生地温数值异常故障的原因进行分析和定位,并找出排除故障的方法。 相似文献
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西安地裂缝是一种典型的地质灾害,自首次出现至今已有近半个世纪.基于活动地裂缝造成的形变去相干特征,通过分析滤波后的差分干涉图的伪相干图来提取活动地裂缝的位置信息.采用两幅ERS影像对西安地区1992～1993年间的活动地裂缝进行了定位研究,通过与该时间段工程地质调查的地裂缝位置比较发现二者有很强的一致性.通过该时间段地裂缝水准对点监测资料比较发现活动地裂缝区域易于产生相位解缠粗差,因此在后续采用差分InSAR获取地裂缝不连续形变信息时需要特别注意. 相似文献
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吉林东部盆地群早白垩世原型盆地恢复 总被引：2，自引：0，他引：2
通过区域地质、电法和地震资料等对吉林东部盆地群早白垩世地层、沉积和构造特征进行研究,从而恢复沉积古地理及原型盆地面貌,结合现今勘探成果与原型盆地控制烃源岩展布,残留盆地改造情况,预测有利勘探区。研究结果表明: 该区早白垩世原型盆地为一大型陆相湖盆的一部分,果松组-鹰嘴砬子组沉积期为初始裂陷孤立盆地发展阶段,林子头组沉积期为断坳转换期,沙河子组- 营城组沉积期为统一的坳陷盆地,至登娄库组沉积期原型盆地完全遭到破坏,泉头组沉积期各盆地进入独立发展阶段。靠近原型盆地湖盆中心的( 扇) 三角洲相、河流相及湖沼相沉积区且位于现今盆地的凹陷区是吉林东部盆地群的有利油气勘探区。 相似文献
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Seismic wavefront evolution of multiply reflected, transmitted, and converted phases in 2D/3D triangular cell model 总被引：1，自引：0，他引：1
Conventionally grid-cell-based schemes for simulating seismic wavefront propagation, such as the finite difference eikonal equation solver or the shortest-path method, usually adopt regular grids or cells in model parameterization to obtaining (but not exclusively) first arrivals only. However, later arrivals, which often result from the velocity interfaces or discontinuities, can be prevalent and significant (sometimes of large amplitude), making them potentially important additional information to use in practical applications. To better approximate the data acquisition geometry and the irregular interfaces, we exploit a triangular shortest-path method (TSPM; that is to use triangular cells in model parameterization) to simulate seismic wavefront evolution, comprising any kind of transmissions, reflections (or refractions), mode conversions, and combinations thereof, in 2D/3D heterogeneous media. A practical procedure, known as the multistage scheme, was incorporated with the TSPM to propagate seismic wavefronts from one interface (or subsurface in 3D) to the next. By treating each separate layer that the wavefront enters as an independent computational domain, one can simulate wavefront transmission and mode conversion by reinitializing it in the adjacent layer and wavefront reflection (and/or conversion) by reinitializing it in the incident layer. To further improve the computational accuracy, a second level of forward star scheme, previously defined in the grid model, is introduced into the triangular cell model. Several examples (including the Marmousi model) are used to demonstrate the viability and versatility of the multistage TSPM in heterogeneous media, even in the presence of high-velocity contrasts involving interfaces of relatively high curvature. With the introduction of the second level of forward star scheme, the total numbers of nodes are reduced sufficiently, and hereafter the computer memory is less required. Most important is that the computing accuracy with the second-level forward star scheme can be largely improved over those with the first level of forward star scheme applied in the multistage TSPM scheme. 相似文献
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The flow past various mechanical cavity, which is a common structure on the surface of the underwater vehicle, and generating hydrodynamic noise has attracted considerable attention in recent years. In this paper, a hybrid method is presented to investigate the hydrodynamic noise induced by mechanical cavities with various shapes. With this method, the noise sources in the near wall turbulences or in the wake are computed by the large eddy simulation (LES) and the generation and propagation of the acoustic waves are solved by the Ffowcs Williams-Hawkings (FW-H) acoustic analogy method with acoustic source terms extracted from the time-dependent solutions of the unsteady flow. The feasibility and reliability of the current method was verified by comparing with experimental data (Wang, 2009). The 2D cavity models with different cross-section shapes and 3D cavity models with different cavity mouth shapes (rectangular and circular) are developed to study the influence of cavity shape on the hydrodynamic noise. By comparing the flow mechanisms, wall pressure fluctuations, near-field and far-field sound propagation distributions, it is found that the quadrangular cavity with equal depths of leading-edge and trailing-edge is preferred for its inducing lower hydrodynamic noise than the cylindrical cavity does. 相似文献
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汶川抗震救灾的基础地理信息综合应急服务 总被引：3，自引：1，他引：2
在5.12汶川特大地震抗震救灾中,国家测绘部门设计和组织实施了以数据成果服务、专用系统服务和专题制图服务为核心的基础地珲信息综合应急服务.其是针对汶川震区地形特点和抗震救灾主体工作需求,快速整合和提供震区已有的基础测绘成果和最新遥感影像资料;快速搭建集震区海量数据集成管理为一体并具备3维影像浏览、对比分析等功能的专用地理信息系统,为灾情评估分析和重建规划研究提供地理空间数据集成展示和分析平台;应需地制作反映受灾范围、受灾程度、救灾响应、规划思路等的各类专题地图和地图集,有效地表达地震灾害的时空分布、重建规划布局等. 相似文献
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激光拉曼光谱技术在获取流体包裹体内压中的应用及讨论 总被引：7，自引：0，他引：7
本文详细介绍了二氧化碳、甲烷、氮气及其混合物拉曼位移与压力的关系。对实验数据进行拟合发现,不管是纯组分还是混合体系中,气体的拉曼位移基本上是随压力增加呈一级指数递减。在混合体系中,压力对拉曼位移的影响最大,含量次之。氮气与甲烷混合由于分子相互作用发生变化,结果使得氮气拉曼位移随压力变化的灵敏度增加,而甲烷的灵敏度却是降低。随压力增加,峰面积、峰半高宽、峰高等参数也将随之变化。实际的应用结果表明,激光拉曼光谱技术是一种获取复杂体系流体包裹体内压的新方法。 相似文献
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中国大陆科学钻探主孔榴辉岩类岩石退变质过程——对超高压变质地体隆升的启示 总被引：6，自引：11，他引：6
中国大陆科学钻探的实施，揭示了深俯冲陆壳的三维结构。超高压变质岩的岩相学详细观察，发现榴辉岩类岩石占0—2000米岩心的60％。大多数榴辉岩的原岩具有长期居留地壳的历史，但是分布在607～783米附近的石榴单斜辉石岩，在成因上与石榴橄榄岩关系密切。从矿物成分，岩石化学特征上看他们构成超镁铁-镁铁质的岩浆杂岩，是俯冲过程中，地幔物质加入于深俯冲的岩片并一起遭受超高压变质作用。榴辉岩质的片麻岩，部分相当于所谓的副片麻岩，在主孔也占一定的地位。实际是中酸性成分的火成岩超高压变质的产物。花岗质片麻岩有多种类型，根据其中所夹的角闪黑云片岩残留体看来大部分应属角闪黑云斜长片麻岩选择性部分熔融的产物。榴辉岩类的变质演化可分为3个阶段。第一阶段(M1约230—240Ma)是超高压变质的峰期，其证据是石榴石、绿辉石、金红石中均发现柯石英的微粒包裹物，石榴橄榄岩中的钛斜硅镁石是其超高压变质历史的见证。第二阶段(M2，226—219Ma)早期退变质阶段，超高压变质岩退变为高压榴辉岩相和角闪岩相岩石，冠状体和后成合晶的生长是此阶段的标志，这些特征性结构反应了岩石的不平衡和再平衡的历史，说明了超高压变质地体的快速隆升。后来(219～180Ma)超高压变质地体长期处于中下地壳，在流体影响下，榴辉岩质片麻岩退变成的黑云角闪斜长片麻岩及绿帘黑云(角闪)片麻岩，他们经选择性部分熔融或经超临界流体的K交代作用转变为黑云角闪二长片麻岩(即所谓正片麻岩)。其中多含有铈褐帘石，成分环带明显，La／Ce=0．42—0．72，且边沿均有绿帘石的边，代表后期叠加的绿帘钠长角闪岩相退变质。第三阶段(M3：170—180Ma)以糜棱岩和构造角砾岩的出现为特征，代表与二次隆升的脆韧性脆性变形的过渡，这些构造岩的基质普遍发育绿泥石、阳起石和方解石，说明了绿片岩相的退变质。所有上述3期的变质作用均与榴辉岩所经历的构造过程相关。显微结构分析可以揭示结晶作用和变形作用之间的相对时序。基于现今已发表的同位素年代学数据可以将苏鲁地区中生代不同阶段的变质作用与构造过程相互联系起来。CCSD主孔所见的变质演化和相关的变形事件对中国大陆中生代大陆动力学提供如下启示；可以肯定华北和杨子两个板块在三叠纪的碰撞(-240Ma)必然引起巨量地壳物质深俯冲至地幔深度，发生超高压变质。超高压变质岩的早期退变质是一个绝热隆升的过程，而后长期滞留中下地壳，发生部分熔融，接着引发进一步的隆升导致伸展体制，伴随以绿帘钠长角闪岩至绿片岩相的退变质。 相似文献
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