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排序方式: 共有175条查询结果,搜索用时 31 毫秒
61.
Aïda Amami-Hamdi Kmar Ben Ismail-Lattrache Ferid Dhahri Rakia Saïd-Benzarti 《Arabian Journal of Geosciences》2014,7(4):1587-1603
Studies on ostracofauna gathered from the Middle–Late Eocene outcropping series of Jebel Bargou anticline, central Tunisia and from an offshore well in the Pelagian Shelf (ABR1) allowed to date major biostratigraphic limits and contribute to improve the precision on the present Eocene biozonation scheme based specially on the planktonic foraminifera markers. Paleogeographic and paleoecological interpretation was derived from an analysis of 60 ostracod species belonging to 38 genera coupled to lithostratigraphic facies interpretation. Ostracods associations indicate an evident similarity between the studied sections with circalittoral taxonomic dominance. In large scale, the ostracofauna recognized in the studied sections shows plentiful similarities with those of Northern Africa and the Middle East regions (Libya, Mauritania, Egypt, Jordan, and Sicilia). The similarities with the genera from Nigeria, Ghana, and Togo are rare and totally absent with those of European margin. Accordingly, during the Middle to Late Eocene, marine connection is evident between Northern Africa and the Middle East, probable between Northern Africa and eastern Africa and totally absent between Northern Africa and European margin because ostracods similarities are absent between European and Tunisian ostracods we were identified except some cosmopolitan forms. 相似文献
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Alper Erdem Yılmaz Yeşim Dede Sağsöz Baybars Ali Fil Murat Tolga Yılmaz 《洁净——土壤、空气、水》2023,51(1):2200032
In this study, domestic wastewater was used as the electrolyte. The work was carried out with an up-flow tubular reactor, made of stainless steel that was used as cathode, while the anode electrode material was aluminum and varying values of flow regime (25, 50, 75 and 100 mL/s for continuous system), initial pH value (5, 6, 7 and 7.8) and current intensity (10, 15 and 20 A) were applied. For domestic wastewater with natural pH, the effluent pH was >9 in the batch system, while in the continuous system the pH was 8–8.5. Likewise, while the effluent temperature was up to 60°C in the batch system, it was at most 35°C in the continuous system. However, the energy consumption values in the continuous system were considerably lower compared with the batch system. At a current intensity of 10 A, 80 kWh of energy per unit volume was consumed in the batch system, while it was 50 kWh for the continuous system. The present results show that the batch system can be used for small wastewater streams whereas the continuous system can be used for large wastewater streams for domestic wastewater treatment. 相似文献
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Marie Lothon Fleur Couvreux Sylvie Donier Françoise Guichard Pierre Lacarrère Donald H. Lenschow Joël Noilhan Frédérique Saïd 《Boundary-Layer Meteorology》2007,124(3):425-447
During the Hydrological-Atmospheric Pilot Experiment (HAPEX)-Sahel, which took place in Niger in the transitional period between
the wet and dry seasons, two French aircraft probed the Sahelian boundary layer to measure sensible and latent heat fluxes.
The measurements over the Niamey area often revealed organised structures of a few km scale that were associated with both
thermals and dry intrusions. We study the impact of these coherent structures using a single day’s aircraft-measured fluxes
and a numerical simulation of that day with a mesoscale model. The numerical simulation at high horizontal resolution (250 m)
contains structures that evolve from streaks in the early morning to cells by noon. This simulation shows distribution, variance
and skewness similar to the observations. In particular, the numerical simulation shows dry intrusions that can penetrate
deeply into the atmospheric boundary layer (ABL), and even reach the surface in some cases, which is in accordance with the
observed highly negatively skewed water vapour fluctuations. Dry intrusions and thermals organised at a few km scale give
skewed flux statistics and can introduce large errors in measured fluxes. We use the numerical simulation to: (i) evaluate
the contribution of the organised structures to the total flux, and (ii) estimate the impact of the organised structures on
the systematic and random errors resulting from the 1D sampling of the aircraft as opposed to the 2D numerical simulation
estimate. We find a significant contribution by the organised structures to the total resolved fluxes. When rolls occur, and
for a leg length of about 30 times the ABL depth, the 1D sampled flux is shown to be sometimes 20% lower than the corresponding
2D flux when the 1D sampling direction is the same as the main axis of the rolls, whereas the systematic error is much lower
when the direction of the leg is transverse to the rolls. In the case of cells, an underestimate of around 10% can still be
observed with the 1D approach independent of direction, due to poor sampling of the energy-containing scales. 相似文献
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珠江口盆地白云南洼珠海组发育陆架边缘三角洲,其不仅是深水区勘探重要的油气储层类型,也是沉积地质学和石油地质学研究的热点。根据高精度三维地震资料,应用三级层序格架内等时地层切片技术,对珠江口盆地白云南洼珠海组陆架边缘三角洲的沉积结构和平面演化开展了详细研究。研究表明,区内存在北部和西北部两个物源方向的陆架边缘三角洲物源供给体系,进而形成连续4期三角洲前积复合体,各期次通过解剖三角洲前积结构和叠置样式可细分为2~5套三角洲前积体,地震上表现为切线斜交型和S型反射结构。不同物源供给体系下的三角洲进积和加积速率差异明显,根据陆架边缘三角洲的演化阶段可划分为初始形成期、发展期和稳定期三个阶段。初始形成期为珠海组四段中晚期,三角洲垂向上均表现为进积,平面上北部物源供给的陆架边缘三角洲形成面积小,西北部物源供给的三角洲面积相对大;发展期为珠海组三段,三角洲垂向上进积和加积均存在,陆架边缘三角洲沉积厚度达到最大,平面上北部物源供给的陆架边缘三角洲—深水扇体系发育一定规模,西北部物源供给的陆架三角洲前缘发育陆架条带砂脊;稳定期为珠海组二段和一段,三角洲垂向结构表现为先进积后加积,三角洲前缘规模变大,陆坡水道和深水扇最为发育。珠海组时期陆架边缘三角洲形成演化受双物源差异供给、相对海平面的先升后降和构造活动的相对稳定共同控制。北部物源供给的珠海组陆架边缘三角洲—深水陆坡沉积体系可作为区内最有利的油气勘探目标。 相似文献
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电子政务是国民经济和社会信息化的重要内容,也是当前和今后一个时期我国信息化工作的重点。本文从信息整合的概念及面临的形势阐述了地震政务网站信息整合分类体系构架和面向公共服务的构成,提出了地震政务网站信息整合的新思路。 相似文献