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具有重要岩石学和构造学意义的科马提岩，最吸引人同时又最令人困惑的特征之一是它的鬣刺结构和分层构造。本文从喷出地表的岩桨冷凝时温度分布、熔体性质与结晶作用的密切联系，把科马提岩浆喷发形成的岩流作为一个冷凝整体。通过与金属铸锭浇注成形和矿石冶炼生产的比较，发现它们在冷凝固结过程中温度场特征、熔体的性质、结晶能力和结晶方式都有十分相似的特点，并以此为出发点详细解析了科马提岩的鬣刺结构和岩石分层构造的形成 相似文献
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GPU accelerated marine data visualization method 总被引：1，自引：0，他引：1
The study of marine data visualization is of great value. Marine data, due to its large scale, random variation and multiresolution in nature, are hard to be visualized and analyzed. Nowadays, constructing an ocean model and visualizing model results have become some of the most important research topics of ‘Digital Ocean'. In this paper, a spherical ray casting method is developed to improve the traditional ray-casting algorithm and to make efficient use of GPUs. Aiming at the ocean current data, a 3D view-dependent line integral convolution method is used, in which the spatial frequency is adapted according to the distance from a camera. The study is based on a 3D virtual reality and visualization engine, namely the VV-Ocean. Some interactive operations are also provided to highlight the interesting structures and the characteristics of volumetric data. Finally, the marine data gathered in the East China Sea are displayed and analyzed. The results show that the method meets the requirements of real-time and interactive rendering. 相似文献
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许进 《广东海洋大学学报》2005,25(4):79-83
通过实验研究,用甲苯磺酸作催化剂的呋喃树脂自硬砂与稀土镁作催化剂生产的球铁件,通常在其铸件表层出现异常组织。提出导致异常组织产生的原因,同时又降低了试件的冲击值,并且采用反应型或屏蔽型涂料将可防止球铁件表层异常组织缺陷,为生产性能良好的球铁件提供技术依据。 相似文献
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Yunquan Li Silin Wu Shi Shu Yiyan Lv Yan Cui 《Marine Georesources & Geotechnology》2020,38(5):604-610
AbstractWith the growing demand for underwater refill engineering, the construction technology of implementing fluidized solidification in underwater pouring has recently received increased attention. However, the environmental impact of underwater casting on surrounding water bodies, especially when the silt is polluted, is still unclear. In this study, a simulated underwater pouring test and a static immersion release test were conducted separately to study the quality of the surrounding water during and after pouring. The results showed that fluidized-solidified silt casting could increase the pH of the surrounding water, even after the pouring had stopped, by approximately 1.0 and the turbidity could reach 200 NTU. No diffusion of Zn and Cu into the surrounding water was observed and while Ni and Cr exhibited slight diffusion, this was at a level well below international water quality standard. During construction, reducing the distance from the seafloor to the bottom of the pouring catheter could reduce the level of pollution. After construction, the use of neutral solidified materials can effectively reduce the pH of the surrounding water and the potential risk of heavy metal dissolution. 相似文献
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C. Baars 《Geological Journal》2013,48(6):603-619
Limestone horizons of Upper Ordovician (Katian) age in southwest Wales contain diverse fossil faunas including rugose corals. The existence of Ordovician Rugosa in Wales was first reported by Murchison in the 1830s, but since then hardly any specimens have been documented systematically until this present study. Newly collected material from the area around Llanddowror (Carmarthenshire) has now confirmed the diversity of rugose corals in the Sholeshook Limestone (Katian age), an arenaceous limestone originating from the shelf edge of the palaeocontinent Avalonia. The majority of the specimens are preserved as moulds. This means that in many instances preservation of the fossils was insufficient for specific identification; nevertheless, it was possible to document a diverse rugose coral fauna, including Helicelasma, probable Grewingkia and Kenophyllum, and a potential early mucophyllid. While associated with considerable difficulties, as some diagnostic features of Rugosa are not visible in moulds, it is demonstrated here that the work with such specimens can result in faunal information which would otherwise be unobtainable. An assemblage of rugose and tabulate corals in the Sholeshook Limestone can be differentiated from a similar assemblage in the neighbouring Robeston Wathen Limestone which has a slightly different lithology. The fauna has strong similarities with other Avalonian (Irish, English, Belgian) as well as Baltic (Estonian and Norwegian) rugose coral faunas. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Pipelines are an important part of urban infrastructure development. As part of a virtual globe (VG), the high-efficiency and high-quality visualization of 3D large-scale and high-density urban pipelines is of great importance. This paper proposes a GPU-based pipeline ray casting method for the visualization of urban-scale pipelines in the framework of a VG. The method involves the initial partitioning of the pipeline data into tiles, based on the relationship between the pipeline layer scale and the discrete global grid system (DGGSs). The pipeline centerline in each tile is then segmented and encoded, and a coarser pipeline bounding volume is subsequently constructed using a geometry shader. Finally, the fine 3D pipeline is rendered using a pixel shader. The results of the experimental implementation of the proposed method show that it satisfies the requirements for the multiscale visualization of pipelines in a VG. Moreover, compared with the traditional polygon-based method, the method facilitates a 20% increase in rendering frame rate for the same pixel level accuracy display effect. It also enables the visualization of the thickness of the 3D pipeline without any obvious effect on the rendering efficiency. 相似文献
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