多缆地震船拖体的阻力及横向姿态预测

目前有关阻力及空间状态的理论计算和模型试验基本上针对单个水下拖体,而对多缆地震船各类拖体的综合受力和姿态则较少受到关注。为方便施工团队在海上快速预测拖体的状态,在国内外学者对水下拖体的流体阻力研究基础上,分析多缆地震船水下拖体的结构和流体阻力特征,提出简化的阻力计算及横向姿态预测方法。文章以常用的多缆地震船拖体配置为例,得到的估算结果与实际的作业状态较为吻合,证实了该方法的有效性。     

SRME技术在澳大利亚Timer Sea地区的应用

表面多次波压制（SRME）技术是目前应用效果较好的多次波衰减技术。在介绍多次波类型和常见压制方法的基础上,引出SRME方法。基于平面波传播模型讨论SRME技术的基本原理,以及针对实际地震数据的迭代预测和减去方法,结合该技术的特点给出实际地震数据应用流程。澳大利亚Timer Sea地区海洋地震资料应用实例表明SRME这种数据驱动的表面多次波压制方法非常实用,尤其对崎岖海底多次波有显著效果。     

Images of the seabed in the Faroe-Shetland Channel from commercial 3D seismic data

A large number of 3D deep seismic surveys in the Faroe-Shetland Channel gives continuous coverage over most of the region. These surveys were designed primarily to image depths in excess of 4 km, use low frequency sources and are recorded at low temporal sample rates. However, commercial 3D data can generate highly detailed images of the seabed due to the high spatial sample rate, typically 12.5 m. This is particularly true in waters below 200 m. Despite geophysical artefacts, the images reveal that there are a number of sedimentary processes at work adjacent to and within this channel. On the West Shetland Shelf, iceberg scouring and moraines reflect the impact of glaciation. On the West Shetland slope there is clear evidence for down-slope processes, such as debris flows, linear erosion channels, basal fans and (one case) slope failure. Along-slope processes are also active as indicated by the presence of sediment waves and contourite mounds. On the floor of the basin, polygonal cracking can be observed. The most spectacular feature appears to be the Judd Deeps, a system of cliffs approximately 200 m high and 40 km across. Traditionally, seabed investigation has been performed using high-resolution surveys. This study shows that deep exploration data can also provide useful images of the seafloor.     

Time-domain computation of large amplitude 3D ship motions with forward speed

Time-domain computations of 3D ship motions with forward speed are presented in this paper. The method of computation is based upon transient Green function. Both linear and nonlinear (large-amplitude) computations are performed where the included nonlinearities are those arising from the incident wave, but the diffraction and radiation forces are otherwise retained as linear. The incident wave can be described by any explicit nonlinear model. Computations over a variety of wave and speed parameters establish the robustness of the algorithm, which include high speed and following waves. Comparison of linear and nonlinear computations show that nonlinearities have a considerable influence on the results, particularly in predicting the instantaneous location of the hull in relation to the wave, which is crucial in determining forefoot emergence and deck wetness.     

Ice-sheet dynamics through the Quaternary on the mid-Norwegian continental margin inferred from 3D seismic data

Reconstructing the evolution of ice sheets is critical to our understanding of the global environmental system, but most detailed palaeo-glaciological reconstructions have hitherto focused on the very recent history of ice sheets. Here, we present a three-dimensional (3D) reconstruction of the changing nature of ice-sheet derived sedimentary architecture through the Quaternary Ice Age of almost 3 Ma. An extensive geophysical record documents a marine-terminating, calving Fennoscandian Ice Sheet (FIS) margin present periodically on the mid-Norwegian shelf since the beginning of the Quaternary. Spatial and temporal variability of the FIS is illustrated by the gradual development of fast-flowing ice streams and associated intensification of focused glacial erosion and sedimentation since that time. Buried subglacial landforms reveal a complex and dynamic ice sheet, with converging palaeo-ice streams and several flow-switching events that may reflect major changes in topography and basal thermal regime. Lack of major subglacial meltwater channels suggests a largely distributed drainage system beneath the marine-terminating part of the FIS. This palaeo-environmental examination of the FIS provides a useful framework for ice-sheet modelling and shows that fragmentary preservation of buried surfaces and variability of ice-sheet dynamics should be taken into account when reconstructing glacial history from spatially limited datasets.     

三维仿真技术在海洋地理环境仿真中的应用

介绍了计算机三维仿真技术的原理，如何实现三维真实景观的再现及实时仿真。指出海陆环境中应用三维仿真技术的特点及实施方法。得到较好三维显示和动画效果、模拟飞行器的漫游过程。     

Deep structure of the crust beneath the Sea of Okhotsk inferred from 3D seismic density modeling

Potential field anomalies of the Sea of Okhotsk region are analyzed for compiling a map of the basement’s tectonic structures. A 3D density model of the Earth’s crust is constructed using seismogeological and experimental-petrophysical data, which made it possible to obtain a visual image of main structures of the region reflecting the observable geophysical anomalies. The obtained data allow a domain located in the central part of the Sea of Okhotsk beyond the limits of the exclusive economic zone of the Russian Federation to be considered as a natural continuation of the continental shelf since the latter is structurally similar to western Kamchatka. The deep structural boundaries rise beneath the large sedimentary Deryugin and Tinro basins, which is characteristic of petroliferous basins.     

三维激光扫描技术在海洋模型试验中的应用

基于三维激光扫描技术,使用Leica ScanStation 2地面三维激光扫描仪对胶州湾物理模型试验地形进行测量.结果表明,三维激光扫描技术比常规的地形测量技术具有更多的优势,为海洋物理模型试验地形提供了一种高效、可行的测量手段.     

VHR Marine 3D Seismics for Shallow Water Investigations: Some Practical Guidelines

The design of very high resolution (VHR) 3D marine surveys not only depends on the theoretical considerations of seismic imaging, but is also dictated by the field conditions and the available budget. The main geophysical controlling factors include the depth and dip of the target, and horizontal and vertical resolution. Working in shallow water environments and at high frequencies will imply constraints on sampling, array directivity and positioning accuracy. In this paper we describe the main requirements and constraints involved in VHR 3D acquisition. The second part of the paper focuses on the flexible acquisition system “Opus3D” recently developed for shallow water investigations. The system provides improvements in imaging resolution in a relatively simple and cost-effective way. Acquisition and positioning constraints limit the system to nearshore studies. The experience gained from various surveys with this new acquisition system allow us to formulate a number of practical specifications and guidelines for 3D survey design in shallow water.     

海上三维双方位融合处理技术在番禺4洼的应用

番禺4洼新近系NWW—SEE向正断层非常发育,这些断层上升盘的构造圈闭是重要的勘探目标。但由于一次三维地震资料采集方向与断层平行,断层附近阴影现象非常严重,表现为信噪比低、同相轴不合理的“下拉”和扭曲畸变的“假象”,严重影响断层上升盘的精细构造落实。为此,实施了垂直于断层方向的二次三维地震采集,使得断层阴影带成像比一次三维有较大改善。为了更好地解决断层阴影带成像难题,针对方位各向异性,对2次采集的三维资料进行了以双方位各向异性叠前深度偏移（PSDM）为核心的双方位融合处理。2个方位各自处理成果和双方位融合处理结果对比表明：对于断层阴影带成像,垂直断层方向采集的三维明显优于平行断层方向采集的三维;而结合2次采集的双方位融合处理资料效果最好：既能有效的消除断层阴影带成像畸变,又能提高信噪比。经研究区油田评价井在断层阴影带的钻探结果证实了双方位融合处理结果的可靠性,同时,可为类似地区解决断层阴影带成像难题提供采集设计和处理技术等方面的借鉴。     

引水工程复杂水流的二、三维嵌套数值模拟

建立宽浅河道与管道水流的二、三维嵌套的数学模型,对基本的控制方程、方程的数值离散格式和求解方法、嵌套连接和初始边界条件等问题进行研究.利用上述方法对某工程实例进行计算,在宽广水域上给出了水力要素的平面分布,在复杂边界强三维流动的计算区域得到其三维运动特性.计算结果与实验资料进行了比较,两者吻合较好,说明嵌套连接的二、三维数学模型是解决某些实际工程问题的一种可靠的和有效的工具.     

FZF2-3型海洋资料浮标系统研制

本文介绍用于我国海洋资料浮标网海洋环境监测的ＦＺＦ２－３型海洋资料浮标系统的设计方案。论述了该系统总体技术性能特征,在海洋监测领域首次研究应用ＩＮＭＡＲＳＡＴ－Ｃ卫星传输海洋监测数据情况及该系统推广应用前景。     

Waves of 3D Marine Structures Slamming at Different Initial Poses in Complex Wind-Wave-Flow Environments

Aimed at the hydrodynamic response for marine structures slamming into water, based on the mechanism analysis to the slamming process, and by combining 3D N?S equation and turbulent kinetic equation with structure fully 6DOF motion equation, a mathematical model for the wind-fluid-solid interaction is established in 3D marine structure slamming wave at free poses and wind-wave-flow complex environments. Compared with the results of physical model test, the numerical results from the slamming wave well correspond with the experimental results. Through the mathematical model, the wave-making issue of 3D marine structure at initial pose falls into water in different complex wind, wave and flow environments is investigated. The research results show that various kinds of natural factors and structure initial poses have different influence on the slamming wave, and there is an obvious rule in this process.     

Automated egg counting and sizing from scanned images: Rapid sample processing and large data volumes for fecundity estimates

The production of eggs in a fish population is a fundamental parameter in fisheries management and ecology. Management decisions are based largely on the abundance and composition of the spawning stock; hence it is essential to estimate the contribution of viable eggs by females of various ages, which may depend on the size and maturation schedules in females of younger ages, and the size and reproductive senescence of older ones. The level of recruitment may also be influenced by the size and quality of eggs. Egg quality can be characterised in a number of ways; however, the most useful methods are those that are efficient and widely available. Estimating potential fecundity and egg size in fish and invertebrate populations has been hindered by the processing time, toxicity, and resources required by traditional methods. We have developed an imaging-based technique that counts and measures oocytes from a gravimetric gonadal sub-sample in relatively little time and at low cost. Sub-samples were preserved in a non-toxic formulation of Gilson's solution, which offers an alternative to other preservatives commonly used in fecundity studies. The technique uses high-resolution optical scans of plated oocytes, imaging software, and user-defined object classifications to separate oocyte from ancillary material likely to be present in a processed sample. Estimates of misclassification are as low as 1% (false-negatives) in automated counts.     

Salt structures in the Laizhouwan depression, offshore Bohai Bay basin, eastern China: New insights from 3D seismic data

Using the new high-quality 3D seismic data, this paper addresses the salt structures in the KL11 area of the Laizhouwan depression in the southern offshore Bohai Bay basin. In the study area, the salt in the Sha-4 Member of the Paleogene Shahejie Formation thickened, and then formed an S–N trending salt wall, which changes shape regularly along its trend from salt diapir to salt pillow. The change in thickness of the suprasalt layers record five growth phases of the salt wall from the Eocene to the Quaternary: (1) early diapirism, (2) active diapirism, (3) passive diapirism, (4) relative structural quiescence, and (5) arching. The evolution of the salt structures was mostly governed by the multi-phase compression induced by the dextral strike-slip of the Tan–Lu fault, which formed a restraining bend in the study area. There was an original passive stock in the south, which was later tectonically squeezed by E–W compression and became a diapir. As the shortening propagated to the north from the original stock, the salt pillow was created in the north. Relative structural quiescence then followed until the next phase of compression, which arched the thick roof of the salt wall.     

基于数字全息显微的海洋浮游生物三维形貌快速重建方法研究

针对海洋浮游生物实时探测中,三维形貌特征难以快速获取的问题,本文提出了一种海洋浮游生物三维形貌快速重建的方法。基于离轴菲涅尔数字全息显微系统,通过改进相位恢复方法预消除相位畸变,直接得到正确的相位信息,进而对浮游生物三维形貌重建。该方法不需要进行后期复杂的相位补偿计算,就可以对浮游生物三维形貌进行快速重建,有利于对动态、微小尺寸的浮游生物进行实时探测及分析。论文对青岛近海岸浮游生物桡足类和夜光虫进行了三维形貌重建,分辨率可达到3.5μm。实验结果为离轴菲涅尔数字全息显微系统用于海洋浮游生物原位、实时探测的可行性提供了依据。     

二维和三维电子地图的空间认知差异研究

讨论了二维和三维电子地图在空间认知特点、空间认知模式和空间认知效果方面的差异。与纸质地图相比,二维电子的地图的空间认知具有动态性、交互性以及制图和读图过程的模糊化等特点,三维电子地图的认知效率更高、认知维度和深度更广。空间认知模式方面,二维电子地图类似于"阅读式",而三维电子地图则类似于"观看式"。二维电子地图对位置、距离、方向等空间格局的认知效果较好,而三维电子地图对目标、形状等空间对象的认知效果较好。