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31.
本文分析了特征点应满足的几种条件,给出了一次范围最小(L1)法,最小二乘法以及粗差探测法进行特征点粗差定位方法,并以模拟实例为例对它们进行了比较,得出了一些有意义的结论。  相似文献   
32.
总结了朝阳西北部金成矿区的区域磁场、重力场等地球物理场的特征及规律,指出了常规物探方法在该区的找金效果,预测了金成矿的远景区段。  相似文献   
33.
广西环江县北山地区喷流沉积铅锌矿资源潜力及找矿方向   总被引:6,自引:2,他引:6  
环江县北山地区铅锌矿均富集在同一地层层位——中上泥盆统,五圩—川山—驯乐NNE向深断裂控制着成矿带,矿床存在大量沉积成岩成矿组构,喷流沉积特征明显。其成矿地质背景、沉积相、礁硅岩套建造、同生断裂活动、赋矿层位等与邻区丹池锡一铅锌多金属矿集区类似,有巨大找矿潜力。  相似文献   
34.
周策  陈文俊 《探矿工程》2004,31(8):36-38
为解决以往定向仪不抗振、岩样采取率不高等问题,利用时间与钻孔空间位置对应的关系,研制成功了KD型定向仪。详细介绍了该定向仪的基本构成、技术参数及现场应用情况。  相似文献   
35.
Shape, size and orientation measurements of quartz grains sampled along two transects that cross zones of increasing metamorphic grade in the Otago Schist, New Zealand, reveal the role of quartz in the progressive development of metamorphic foliation. Sedimentary compaction and diagenesis contributed little to the formation of a shape‐preferred orientation (SPO) within the analysed samples. Metamorphic foliation was initiated at sub‐greenschist facies conditions as part of a composite S1‐bedding structure parallel to the axial planes of tight to isoclinal F1 folds. An important component of this foliation is a pronounced quartz SPO that formed dominantly by the effect of dissolution–precipitation creep on detrital grains in association with F1 strain. With increasing grade, the following trends are evident from the SPO data: (i) a progressive increase in the aspect ratio of grains in sections parallel to lineation, and the development of blade‐shaped grains; (ii) the early development of a strong shape preferred orientation so that blade lengths define the linear aspect of the foliation (lineation) and the intermediate axes of the blades define a partial girdle about the lineation; (iii) a slight thinning and reduction in volume of grains in the one transect; and (iv) an actual increase in thickness and volume in the survivor grains of the second transect. The highest‐grade samples, within the chlorite zone of the greenschist facies, record segregation into quartz‐ and mica‐rich layers. This segregation resulted largely from F2 crenulation and marks a key change in the distribution, deformation and SPO of the quartz grains. The contribution of quartz SPO to defining the foliation lessens as the previously discrete and aligned detrital quartz grains are replaced by aggregates and layers of dynamically recrystallized quartz grains of reduced aspect ratio and reduced alignment. Pressure solution now affects the margins of quartz‐rich layers rather than individual grains. In higher‐grade samples, therefore, the rock structure is characterized increasingly by segregation layering parallel to a foliation defined predominantly by mica SPO.  相似文献   
36.
We have measured P- and S-wave velocities on two amphibolite and two gneiss samples from the Kola superdeep borehole as a function of pressure (up to 600 MPa) and temperature (up to 600 °C). The velocity measurements include compressional (Vp) and shear wave velocities (Vs1, Vs2) propagating in three orthogonal directions which were in general not parallel to inherent rock symmetry axes or planes. The measurements are accompanied by 3D-velocities calculations based on lattice preferred orientation (LPO) obtained by TOF (Time Of Flight) neutron diffraction analysis which allows the investigation of bulk volumes up to several cubic centimetres due to the high penetration depth of neutrons. The LPO-based numerical velocity calculations give important information on the different contribution of the various rock-forming minerals to bulk elastic anisotropy and on the relations of seismic anisotropy, shear wave splitting, and shear wave polarization to the structural reference frame (foliation and lineation). Comparison with measured velocities obtained for the three propagation directions that were not in accordance with the structural frame of the rocks (foliation and lineation) demonstrate that for shear waves propagating through anisotropic rocks the vibration directions are as important as the propagation directions. The study demonstrates that proper measurement of shear wave splitting by means of two orthogonal polarized sending and receiving shear wave transducers is only possible when their propagation and polarization directions are parallel and normal to foliation and lineation, respectively.  相似文献   
37.
大学城的另类定位--广州旅游的"太阳"   总被引:1,自引:0,他引:1  
从旅游的角度,运用定性分析和比较分析的方法,分析广州大学城,发现它在广州所有景区中,最有资格和条件担当广州旅游的“太阳”。它位于广州市番禺区新造镇小谷围岛,投资规模、大学数量、占地面积和规划人口容量皆为中国之最,是世界最大的人造景区,具有浓浓的文化氛围、时代气息,能够体现与闪烁广州的灵魂与精神。为此,广州应在大学城的建设中为未来角色创造更好的条件。  相似文献   
38.
Soil water repellency is a widespread phenomenon with the capacity to alter hydrological and geomorphological processes. Water repellency decays with time, and the consequences are only of concern during the timescale at which the water repellency persists. This study aimed to characterize the influence of temperature and humidity on the breakdown of water repellency. Apparent contact angle measurements were carried out on samples consisting of sand treated with stearic acid as well as naturally repellent dune sands and composts. Temperature and humidity were controlled using a cooled incubator and a purpose designed enclosed box in which humidity could be raised or lowered. Results showed the contact angle of the stearic‐acid‐treated sands decayed with time and that there was a significant increase with stearic acid concentration. For all samples, the decay in apparent contact angle could be described with a continuous breakdown model. The stearic‐acid‐treated sands showed a significant increase in contact angle with relative humidity at a temperature of 10 and 20 °C. These differences diminished with increasing temperature. Similar results were seen for the dune sands and composts. Despite the influence of temperature and humidity on contact angles, there was no significant change in the rate at which the contact angle decayed in any sample. Absolute humidity was found to provide a more relevant indicator than relative humidity when assessing the influence of humidity on repellency over a range of temperatures. The contact angle initially increased with absolute humidity before plateauing owing to the confounding effect of temperature. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
39.
利用多角度倾斜摄影技术获取的倾斜影像成果来更新和构建城市三维实景纹理映射成为数字城市建设中的一个重要应用。本文采用基于DLG和3Dmax生成的建筑物模型,结合SWDC-5的多角度倾斜影像,通过自动选择纹理、自动编辑纹理、自动纹理映射等一系列步骤,自动生成大区域建筑物三维实景数字城市。并通过实验数据对该计算方法的可靠性进行验证,结果表明:该系统的数字化程度远远高于传统方法。  相似文献   
40.
以SRTM-DEM为控制的光学卫星遥感立体影像正射纠正   总被引:3,自引:1,他引:2  
张浩  张过  蒋永华  汪韬阳 《测绘学报》2016,45(3):326-331
针对全球测图缺少统一的控制基准的问题,提出了利用SRTM-DEM作为控制基准,对光学卫星遥感影像进行正射纠正的方法。首先,对光学卫星影像构建的立体影像对进行自由网平差并制作DEM;然后,以SRTM-DEM作为控制,将DEM作为单元模型,进行独立模型法DEM区域网平差,获得单元模型的定向参数;最后,改正立体影像的成像几何模型参数,进行正射纠正。选取湖北咸宁和江西某地两个测区的资源三号数据进行试验,试验结果表明,资源三号正视全色影像的平面定向精度由12.93像素提高到6.85像素。  相似文献   
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