环渤海区域及邻区现今地壳构造运动形变特征分析     

赵旭坤  张俊  雷前坤  范成成 《大地测量与地球动力学》2019,39(11):1101-1105

将环渤海区域划分为5个次级块体，利用整体旋转与线性应变模型分析2009~2014年中国大陆构造环境监测网络的GPS对地观测速度场数据，得到相对于欧亚板块0.5°×0.5°的水平运动速度场和应变场。分析形变速度场和应变场的空间变化发现，环渤海区域整体上呈现0.25×10^-9/a的NW-SE 111.3°的双向趋势性扩张运动，太行块体、山西块体分别呈NW-SE 116.3°、NW-SE 130°的微弱扩张运动，胶辽块体、冀鲁块体和阴山-燕山块体分别存在NW-SE 144.3°、NE-SW 39.5°和NW-SE 155.6°的微弱压缩运动，其中太行块体的扩张运动量级相对于其他次级块体较大。尽管环渤海区域内部各次级块体的形变在空间上存在以上差异，但整体上环渤海区域主压应变轴方向基本为NEE-SWW，主张应变轴方向为NNW-SSE，且主压应变轴走向为NE 47.70°～89.74°，与利用地球物理方法得到的主压应变轴优势方向大体一致，表明环渤海区域现今地壳运动相对稳定。  相似文献   

Investigation of highly efficient algorithms for solving linear equations in the discontinuous deformation analysis method          下载免费PDF全文

Xiaodong Fu  Qian Sheng  Yonghui Zhang  Jian Chen 《国际地质力学数值与分析法杂志》2016,40(4):469-486

Large‐scale engineering computing using the discontinuous deformation analysis (DDA) method is time‐consuming, which hinders the application of the DDA method. The simulation result of a typical numerical example indicates that the linear equation solver is a key factor that affects the efficiency of the DDA method. In this paper, highly efficient algorithms for solving linear equations are investigated, and two modifications of the DDA programme are presented. The first modification is a linear equation solver with high efficiency. The block Jacobi (BJ) iterative method and the block conjugate gradient with Jacobi pre‐processing (Jacobi‐PCG) iterative method are introduced, and the key operations are detailed, including the matrix‐vector product and the diagonal matrix inversion. Another modification consists of a parallel linear equation solver, which is separately constructed based on the multi‐thread and CPU‐GPU heterogeneous platforms with OpenMP and CUDA, respectively. The simulation results from several numerical examples using the modified DDA programme demonstrate that the Jacobi‐PCG is a better iterative method for large‐scale engineering computing and that adoptive parallel strategies can greatly enhance computational efficiency. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Late Holocene vertical land motion and relative sea‐level changes: lessons from the British Isles     

Ian Shennan  Glenn Milne  Sarah Bradley 《第四纪科学杂志》2012,27(1):64-70

Vertical land motion caused by continuing glacial isostatic adjustment is one of several important components of sea‐level change and is not limited just to previously glaciated regions. A national‐scale analysis for the British Isles shows an ellipse of present‐day relative uplift (relative sea‐level fall), ～1.2 mm a^?1, broadly centred on the deglaciated mountains of Scotland. The pattern of three foci of relative subsidence, ～1 mm a^?1, results from the additional interactions of the deglacial meltwater load on the Atlantic basin and the continental shelf, and the signal due to far‐field ice sheets. At a local scale, sediment compaction can more than double the rate of relative land subsidence. Relative land‐level change (the negative of relative sea‐level change) is not the same as vertical land motion. There is a spatial pattern in the difference between relative land‐level change and vertical land motion, with differences at present of approximately ?0.1 to ?0.3 mm a^?1 around the British Isles and +2.5 to ?1.5 mm a^?1 globally. For the wider scientific and user community, whether or not the differences are considered significant will depend upon the location, time frame and spatial scale of the study that uses such information. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

聚合物驱组合段塞分注实验研究     

李宜强  林丽华  梁双庆 《海洋地质译丛》2010,(1):85-89

萨尔图油田南二区东部140号断层以东地区葡11—4油层，以多段多韵律和正韵律沉积为主，平均孔隙度30．0％，平均空气渗透率1980×10^-3μm2。水驱结束时该油层平均含水92％，采出程度39．5％。计划对该区块实施聚合物驱开采。以往经验认为，组合段塞调整注聚技术能够有效改善流度控制作用。然而对组合注入情况下如何进一步提高驱油效果、注入井分注时机、层段注入强度对开发效果有何影响却很少探讨。通过室内驱油实验，在聚驱的组合段塞注入不同时机（水驱空白阶段、含水下降阶段、含水稳定阶段、含水回升阶段）下调整注入强度实施分注以及在含水回升分注基础上进一步调整注入强度，同时对比不分注实验，评价各方案驱油效果。实验表明：不实施分注时聚驱采收率在水驱基础上提高了19．07个百分点，而组合段塞注入时实施分注均能够在不分注基础上进一步提高驱油效果；空白水驱时实施分注采收率提高幅度最大，为26．55个百分点；随着分注时机的滞后采收率提高幅度增加值依次递减，分注时机越早越好。  相似文献   

Effects of wave–current interaction on the current profile     

Maitane Olabarrieta  Raul Medina  Sonia Castanedo 《Coastal Engineering》2010

Wave–current laboratory experiments have shown that the logarithmic current profile observed in pure current flows is modified due to the presence of waves. When waves propagate opposite the current, an increase in the current intensity is achieved near the mean water level, while a reduction is obtained for following waves and currents. With the aim of analyzing these nonlinear effects along the whole water column, an Eulerian wave–current model is presented. In contrast to previously presented wave–current models, the present is able to include the variation of the free surface elevation due to the wave motion and the effect of a non hydrostatic pressure field. Therefore it does not restrict its application to waves in shallow waters. Moreover, the model is able to simulate all the possible angles between waves and currents.  相似文献   

关于公主岭市1∶1000比例尺地形图成果现状及长远发展问题的探讨     

徐咏君 《东北测绘》2010,(5):182-183

公主岭市依靠得天独厚的地缘优势和优惠的投资政策,使近十年的建设得到了迅速发展。房地产开发、城市路网改造、招商引资工程建设对测绘工作提出了更高的要求。公主岭市现有的1∶1 000比例尺地形图是1993年测绘的聚脂薄膜蒙绘图,测绘面积小,已使用了11年,现势性比较差。现以施测吉林华润生化黄龙工业园1∶1 000比例尺地形图为例,探讨如何满足规划设计急需和城市长远发展的问题。  相似文献   

The ground-state entanglement in the spin-XX chain with a magnetization current     

张勇  王川  金光生 《海洋学报(英文版)》2010,29(11)

The ground-state entanglement in a transverse spin-1/2 XX chain with a magnetization current is studied. By introducing a magnetization current to the system, a quantum phase transition to current-carrying phase may be presented with the variation of the driving field λ for the magnetic field h>1; and the ground-state entanglement arises simultaneously at the critical point of quantum phase transition. In our model, the introduction of magnetization current may result in more entanglement between any two nearest-neighbour spins.  相似文献   

广东流沙湾4个测站2个周日潮流观测的准调和分析   总被引：2，自引：0，他引：2  

张静  孙省利  吴灶和  陈春亮  张瑜斌 《台湾海峡》2010,29(3):408-413

采用短期资料的潮流准调和分析方法,对水深为4.4～17.0 m的流沙湾4个测站2个周日潮流观测获得的表、中、底层的潮流资料进行了分析,分别计算了4个测站O1、K1、M2、S2、M4、MS4共6个主要分潮的潮流调和常数,并给出了各观测站位在各层的潮流椭圆要素.计算结果表明：流沙湾主要为日潮流海区,其中湾外为规则日潮流,湾内为不规则日潮流;湾外主要分潮流的北分量一般大于东分量,而湾内主要分潮流的北分量一般小于东分量.观测期间余流的流向主要呈西北向,最大余流流速出现在湾内地形突然收窄处,且在湾内中层余流流速要大于表、底层余流流速.整个海区潮流的可能最大流速表层在57～107 cm/s之间,中层在53～106 cm/s之间,底层在34～98 cm/s之间.流沙湾湾外潮流主要为顺时针的旋转流运动,湾内为带有旋转流的往复流运动.  相似文献   

Effects of different operational modes on the flood‐induced turbidity current of a canyon‐shaped reservoir: case study on Liuxihe Reservoir,South China     

Sheng Wang  Xin Qian  Bo‐Ping Han  Lian‐Cong Luo  Rui Ye  Wen Xiong 《水文研究》2013,27(26):4004-4016

Suspended matter is an important indicator of water quality in freshwater systems. The flood‐induced turbidity current plays a dominant role in the seasonal dynamic of suspended matter in the Liuxihe Reservoir (23°45′50″N; 113°46′52″E), a large, stratified reservoir at the Tropic of Cancer in southern China. Field measurements show that loading and distribution of suspended matter in the reservoir differ in typical wet, dry and medium years, as a result of different discharge volumes and water level variation patterns. Using historical data and the practical demand for water supply and flood control, we generalized two feasible reservoir operational modes: flood impounding mode (drawing down the reservoir to a low level before flood events to impound inflow during the flooding season) and moderate level change mode (drawing down the reservoir to a moderate level before flood events, then keeping the level within the flood control level during runoff events). To examine the effects of different operational modes and outlet depths on the reservoir's flood‐induced turbidity current, a numerical simulation model was applied in three types of hydrological conditions. The results show that the mode with moderate drawdown and recharge processes can decrease loading of suspended matter in spring and promote turbidity current release during flood events, and upper withdrawal can improve the effects of turbid water release. We suggest that more attention should be focused on water quality management in the reservoir operation stage, severe artificial water level fluctuation being avoided and selective withdrawal becoming an optional management measure. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Observations and analyses of floc size and floc settling velocity in coastal salt marsh of Luoyuan Bay, Fujian Province, China   总被引：1，自引：0，他引：1  

WANG Aijun  YE Xiang  CHEN Jian 《海洋学报(英文版)》2010,29(3):116-126

In coastal environments, fine-grain sediments often aggregate into large and porous flocs. ElectroMagnetic Current Meters (EMCM) and Laser In Situ Scattering and Transmissometry (LISST-ST) have been deployed within a Spartina alterniflora marsh of the Luoyuan Bay in Fujian Province, China, to measure the current velocity, the floc size and the settling velocity between 15 and 22 January 2008. During the observations, the near-bed water was collected in order to obtain the suspended sediment concentration (SSC) and constituent grain size. Data show that: (1) the nearbed current velocities vary from 0.1 to 5.6 cm/s in the central Spartina alterniflora marsh and 0.1–12.5 cm/s at the edge; (2) the SSCs vary from 47 to 188 mg/dm 3 . The mean grain size of constituent grains varies from 7.0 to 9.6 μm, and the mean floc sizes (MFS) vary from 30.4 to 69.4 μm. The relationship between the mean floc size and settling velocity can be described as: w s =ad b , in which w s is the floc settling velocity (mm/s), a and b are coefficients. The floc settling velocity varies from 0.17 to 0.32 mm/s, with a mean value of 0.26 mm/s, and the floc settling velocity during the flood tide is higher than that during the ebb tide. The current velocity and the SSC are the main factors controlling the flocculation processes and the floc settling velocity.  相似文献