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1.
针对城区内涝淹没范围和水深模拟问题,该文提出了一种基于约束Delaunay不规则三角网与三棱柱的城区内涝淹没模拟算法。该算法以沿地面三角形的顶点垂直向上引垂线形成的三棱柱为计算单元,通过\"等体积\"的方法,建立时间序列切片下的淹没水深和积水量的关系,据此实现淹没范围和水深模拟。以北京师范大学(简称\"北师大\")主校区为例,对单汇水区的水面高程上升模拟结果与实际观测值进行对比,基本吻合;并与传统栅格DEM的淹没效果进行了对比,表明该算法正确有效。  相似文献   
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In southern Taiwan the initial collision of the Luzon volcanic arc with the passive continental margin of China results in the emergence of an accretionary prism of, predominantly, turbidites in composition, thus providing an appropriate place to study the temporal and spatial variation of deformation during the transition of subduction to arc-continent collision. Field surveys have recently been carried out in slightly metamorphosed rocks along the well-exposed Jinlun-Taimali coast in southeastern Taiwan. Three folding phases are identified in the area. The first phase is characterized by gently dipping but widely distributed phyllitic cleavage (S1). The second phase is represented by sparsely distributed crenulation cleavage (S2) that folded the phyllitic cleavage. The third phase is characterized by E–W trending antiforms (F3) that involved both types of pre-existing cleavages. Restoration of such an antiform in the north using a method proposed in this paper reveals that phyllitic cleavage in the overturned beds dips gently towards the southeast or east-southeast before the antiform, in relation to the first-phase thrusting or folding under regional ESE-WNW compression. From the first to third phase, the maximum horizontal compression underwent an about 90° anticlockwise rotation from ESE-WNW to E–W or NE–SW to N–S, and the deformation depth seems to decrease drastically, in terms of the decreasing proportion of pervasive deformation. All these variations are attributed to the oblique arc-continent collision that exhumed the whole accretionary prism and induced a local stress perturbation in southeastern Taiwan.  相似文献   
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《GFF》2012,134(4):193-202
Abstract

In Scania, the southernmost province of Sweden, Upper Cretaceous strata are found in depositional basins associated with the Sorgenfrei‐Tomquist Zone which transects Scania in a NW‐SE direction. The Vomb Trough was developed during the Late Cretaceous as an isolated wedge‐shaped basin linked with the Danish Basin and the Polish Trough to the SW. Cretaceous strata are approximately 1000 m thick and include an up to 800 m thick Santonian‐Campanian sequence formed contemporarily with the peak of uplift movements in the Tornquist Zone. The Campanian deposits in the Vomb Trough consist of a variety of matrix‐rich greywackes, calcite cemented litharenites and conglomeratic lithofacies. The sedimentary characteristics of the investigated deposits verify a restricted inner shelf depositional environment strongly influenced by influx of terrigenous clastics from adjacent highs. Conglomerates with pebbles originating from the uplifted Palaeozoic Plateau to the NE occur frequently in the outcrops. An inner shelf environment is also evidenced by the fossil composition and the presence of glaucony. Temporary nearshore and freshwater‐brackish conditions are indicated by the presence of the microalga Botryococcus in occasional samples. Authigenic zeolite (clinoptilolite) in the sediments indicates temporarily alkaline depositional conditions in shallow bodies of water with limited circulation and mixing. The zeolite crystallization is probably related to volcanic activity and hydrothermal flushing along the Fyledalen Fault Zone bordering the Vomb Trough to the NE.  相似文献   
4.
基于数码相机立体像对的物体3维信息快速获取方法   总被引:5,自引:0,他引:5  
研究了数码相机的内方位元素检测和镜头畸变差校正,应用近景摄影测量的原理与方法,提出了一种基于立体像对无物方控制的物体表面3维模型信息快速获取方法,试验表明,该方法获取3维信息速度快、精度较高。同时文中还比较了可变焦数码相机和固定焦距相机在获取3维信息精度方面的差异。  相似文献   
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1 Methodsfororientatinginitialdirec tioninindustrialsurveyDifferentfromconventionalengineeringsurvey,thedistancebetweenthetwoangle measurementdevicesinindustrialsurveyisnomorethantenmeters.Theaccu racyforthemeasurementofobjectpointsisrequiredtobebetween± ( 0 .0 2~ 0 .0 5~ 0 .2 0 )mm ,sotheaccu racyfortheorientationoftheinitialdirectionoughttobehigh .Theexistingmethodsfororientatingtheinitialdirectionbetweenthetwoangle measurementdevicesincludemethodofusinginnertarget,collimatormethod,metho…  相似文献   
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1 IntroductionThecornercubeprismorretroreflectorisexten sivelyusedinplaceofthemovablemirrorinanin terferometer,orasacooperativetargetinrangefinder.Ithasthreesurfaces,whichareperpendic ulartoeachotherandcalledtherightangularsur faces.Aninclinedisoscelestr…  相似文献   
9.
俯冲-增生型造山带增生楔流体研究进展   总被引:3,自引:0,他引:3  
俯冲-增生型造山带弧前增生楔流体的特点为:盐度低、氯化物含量异常低,并含有丰富的CO2和CH4。流体以扩散式或沿断层带渠道式活动;泥火山、张裂隙充填脉、碳酸盐壳、深海生物群是流体活动的直接体现;流体活动影响着增生楔的内部结构和构造样式;增生楔中流体活动特征的研究对研究造山带的地质演化及矿床成因具有重要意义。  相似文献   
10.
    
The determination of the gravitational potential of a prism plays an important role in physical geodesy and geophysics. However, there are few literatures that provide accurate approaches for determining the gravitational potential of a prism. Discrete element method can be used to determine the gravitational potential of a prism, and can approximate the true gravitational potential values with sufficient accuracy (the smaller each element is, the more accurate the result is). Although Nagy’s approach provided a closed expression, one does not know whether it is valid, due to the fact that this approach has not been confirmed in literatures. In this paper, a study on the comparison of Nagy’s approach with discrete element method is presented. The results show that Nagy’s formulas for determining the gravitational potential of a prism are valid in the domain both inside and outside the prism.  相似文献   
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