994 resultados para 7038-401


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<正> 按照Enskog-Chapman稀薄气体动力学理论,单原子分子气体的粘性系数为η=5/12 ((πmkT)~(1/2))/(πσ~2Ω~(2,2)~

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A new numerical method for solving the axisymmetric unsteady incompressible Navier-Stokes equations using vorticity-velocity variables and a staggered grid is presented. The solution is advanced in time with an explicit two-stage Runge-Kutta method. At each stage a vector Poisson equation for velocity is solved. Some important aspects of staggering of the variable location, divergence-free correction to the velocity held by means of a suitably chosen scalar potential and numerical treatment of the vorticity boundary condition are examined. The axisymmetric spherical Couette flow between two concentric differentially rotating spheres is computed as an initial value problem. Comparison of the computational results using a staggered grid with those using a non-staggered grid shows that the staggered grid is superior to the non-staggered grid. The computed scenario of the transition from zero-vortex to two-vortex flow at moderate Reynolds number agrees with that simulated using a pseudospectral method, thus validating the temporal accuracy of our method.

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Apresenta e contextualiza a integração de uma coleção de textos acadêmicos no projeto de Biblioteca Digital da Câmara dos Deputados, tomando por base os conceitos relacionados à atual Sociedade da Informação ou Sociedade do Conhecimento. Descreve o estado da arte do funcionamento de bibliotecas digitais em instituições governamentais no Brasil. Propõe a incorporação da coleção de monografias, dissertações e teses, resultantes dos cursos de pós-graduação oferecidos pelo Centro de Formação e Treinamento da Câmara dos Deputados, como coleção piloto de implantação da Biblioteca Digital.

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将CE/SE方法推广到二维固体流体弹塑性问题的数值计算,同时结合杂交粒子水平集方法追踪物质界面和合适的边界条件,提出一套完整的二维Euler型流体弹塑性计算方案.通过长钨杆侵彻装甲钢实验的数值模拟,对方法的精度和有效性进行验证.

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残余应力一直是微系统技术(MTS)发展中一个令人关注的问题,它影响着MEMS器件设计、加 工和封装的全过程。考虑薄膜中残余应力的起源,介绍测量残余应力的主要方法,并就计算薄膜中残余应力的Stoney公式及其推广形式作了详细的讨论,针对微尺度下残余应力对MEMS结构力学行为的影响,例如屈曲和粘附等进行了初步的分析。

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以构造地震孕震机制之三即交汇断层粘滑发震为模拟对象,利用双轴加载实验系统和红外热像仪对自然界经常出现的断层组合模式——不同交汇角度的组合断层的物理模型进行了室内加载实验,利用红外热像仪和声发射仪分别测定了加载过程中试样表面的红外辐射及断层活动的声发射时间序列。结果表明:(1) 声发射及红外辐射的时间序列特征受加载过程中试样的力学行为所控制,并表现出阶段性变化特点;(2) 声发射与红外辐射特征与断层几何结构有密切关系,当主应力与主断层成45°角时,红外辐射异常区主要沿主断层发育;(3) 垂直交汇的断层与斜交断层的声发射及红外辐射特征有明显差异,交汇角度(1°~90°)越大,交汇点处的红外辐射异常越明显。

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Blake, Sacramento. Diccionario bibliographico brazileiro. Rio de Janeiro: Typ. Nacional, 1883-1902.v. 2, p. 377

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Eguíluz, Federico; Merino, Raquel; Olsen, Vickie; Pajares, Eterio; Santamaría, José Miguel (eds.)

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<正>前言爆炸处理水下海淤软基是一项新技术。国家经委、国家教委、中国科学院等单位列为国家第一批100项与企业横向联合的重点科技项目。连云港建港指挥部,中国科学院力学研究所,锦屏磷矿、交通部第三航务勘探设计院等四单位组织科研组联合攻关。经过四年的工程实践、工程性试验、模型和机理试验等,取得了大量系统的数据,写出了近20篇科学技术报告,并由交通部和中国科学院组织了(钅监)定。这些科技报告经由本文作者审定。为了对这项新技术有一个全面的介绍,作者将科研组所提供的报告作一综述,并阐明了自己的一些观点。科研组各单位先后参加工作达40余人,他们在很艰苦条件下取得了这些宝贵的资料(见本文所引文献),作者对于参加这项工作的所有同志,和本文所参考报告的作者们表示感谢!

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Creative Commons Reconocimiento-NoComercial 3.0 España

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ENGLISH: Beginning in February 1972 the usual seasonal cooling of the surface water of the eastern Pacific Ocean in the region of the Peru Current and along the equator failed to develop. By July tropical coastal and equatorial island stations and ships crossing the equator were recording sea-surface temperatures which were 6° to 8°F (3.3°-4.4°C) above the long-term mean. The anomalies spread over most of the eastern tropical Pacific and westward into the central equatorial Pacific through September. During October surface temperatures at coastal stations along South America were returning to normal, but in November and December 1972 temperatures rose rapidly again, with a near-record temperature anomaly of 8.1°F (4.2°C) above the long-term mean recorded at Puerto Chieama, Peru (7°42'S-79°27'W). After January 1973 sea-surface temperatures began returning to normal over most of the eastern tropical Pacific, and by March 1973 the El Nino had completed its cycle. Monthly sea-surface temperature anomalies over the eastern tropical Pacific are discussed to show the extent and magnitude of warming. Annual temperature profiles at several South American coastal and equatorial island stations are compared with temperature profiles for the 1957-1958 and 1965 EI Nino years. Characteristics of the temperature anomaly profiles at Puerto Chicama during several very warm years for the 1925-1972 period are also compared. Finally, meteorological factors contributing to a relaxation of the southeast trade winds and to the decreased unwilling along the coast of South America in 1972-1973 are examined. SPANISH: A comienzos de febrero de 1972, no se registró el enfriamiento común estacional del agua superficial del Océano Pacífico oriental en la región de la Corriente del Perú y a lo largo del ecuador. En julio las estaciones tropicales, costeras y de las islas ecuatoriales, y los barcos que cruzaban la linea ecuatorial registraron temperaturas superficiales del mar de 6° a 8°F (3.3°-4.4°C) más altas que la media a largo plazo. Las anomalías se esparcieron sobre la mayoría del Pacífico oriental tropical, y al oeste en el Pacífico central ecuatorial. En octubre, las temperaturas superficiales de las estaciones costaneras a lo largo de Sudamérica volvieron a la normalidad, pero en noviembre y diciembre de 1972, las temperaturas de nuevo ascendieron rápidamente con una anomalía de temperatura que alcanzó 8.1°F (4.2°C) sobre la media a largo plazo registrada en Puerto Chicama, Perú (7°42'S-79°27'W). Después de enero 1973 las temperaturas de la superficie del mar volvieron rápidamente a la normalidad en la mayoría del Pacífico oriental tropical y en marzo de 1973 el Niño había completado su ciclo. Se discuten las anomalías mensuales de las temperaturas de la superficie del mar en el Pacífico oriental tropical para indicar la extensión y magnitud del calentamiento. Los perfiles anuales de temperatura en varias estaciones costeras y de las islas ecuatoriales sudamericanas se comparan con los perfiles de temperatura de los años en que ocurrió el Niño en 1957-1958 y 1965. Se comparan también las características de los perfiles de las anomalías de temperatura en Puerto Chicama durante varios años muy cálidos para el período de 1925-1972. Finalmente, se examinan los factores meteorológicos que contribuyen al debilitamiento de los vientos alisios del sudeste y a la reducción del afloramiento a lo largo de la costa sudamericana en 1972-1973. (PDF contains 48 pages.)

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HIGHLIGHTS FOR FY 2005 1. Assisted with a study to assess hurricane impacts to Gulf sturgeon critical foraging habitat. 2. Documented Gulf sturgeon marine movement and habitat use in the Gulf of Mexico. 3. Documented Gulf sturgeon spawning with the collection of fertilized eggs in the Apalachicola River, Florida. 4. Documented Gulf sturgeon spawning with the collection of fertilized eggs in the Yellow River, Florida. 5. Assisted with benthic invertebrate survey at Gulf sturgeon marine foraging grounds. 6. Implemented Gulf Striped Bass Restoration Plan by coordinating the 22nd Annual Morone Workshop, leading the technical committee, transporting broodfish, and coordinating the stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system. 7. Over 87,000 Phase II Gulf striped bass were marked with sequential coded wire tags and stocked in the Apalachicola River. Post-stocking evaluations were conducted at 45 sites in the fall and spring and 8 thermal refuges in the summer. 8. Completed fishery surveys on 4 ponds on Eglin AFB totaling 53 acres, and completed a report with recommendations for future recreational fishery needs. 9. Completed final report for aquatic monitoring at Eglin AFB from 1999 to 2004. 10. Completed a field collection of the endangered Okaloosa darter to be incorporated into a status review to be completed in FY06. 11. Provided technical assistance to the Region 4 National Wildlife Refuge (NWR) program on changes to the fishery conservation targets for the region. Also provided technical assistance to four NWRs (i.e., Okefenokee NWR, Banks Lake NWR, St. Vincent NWR, and St. Marks NWR) relative to hurricanes and recreational fishing. 12. A draft mussel sampling protocol was tested in wadeable streams in Northwest Florida and southwest Georgia, and an associated field guide, poster, and Freshwater Mussel Survey Protocol and Identification workshop were completed in FY05. 13. Implemented recovery plan and candidate conservation actions for 14 listed and candidate freshwater mussels in the Northeast Gulf Watersheds. 14. Initiated or completed multiple stream restoration and watershed management projects. A total of 7.5 stream miles were restored for stream fishes, and 11 miles of coastline were enhanced for sea turtle lighting. A total of 630 acres of wetlands and 2,401 acres of understory habitat were restored. 15. Conducted a watershed assessment to develop a threats analysis for prioritizing restoration, protection, and enhancement to natural resources of Spring Creek, Georgia and Canoe Creek, Florida. 16. Continued the formation of an Unpaved Road Interagency Team of Federal, State, and local agencies in Northwest Florida to promote stream protection and restoration from unpaved road sediment runoff. Began the development of a technical committee agreement. 17. Conducted Alabama Unpaved Road Inventory within the Northeast Gulf Ecosystem. Data collection will be completed during FY06. 18. Finalized the development of two North Florida hydrophysiographic regional curves for use by the Florida Department of Transportation (DOT) and others involved with stream restoration and protection. Initiated the development of the Alabama Coastal Plain Riparian Reference Reach and Regional Curves for use by the Alabama Department of Environmental Management (ADEM). 19. Provided technical assistance in collecting data, analysis, and thesis formulation with Troy University, Alabama, to identify the influence of large woody debris in southeastern coastal plain streams. 20. Completed pre- and post-restoration fish community monitoring at several restoration projects including Big Escambia Creek, Magnolia Creek, and Oyster Lake, Florida. 21. Established a watershed partnership for the Chipola River in Alabama and Florida and expanded development and participation in the Spring Creek Watershed Partnership, Georgia. 22. Continued to identify barriers which inhibit the movement of aquatic species within the Northeast Gulf Ecoregion. 23. Completed a report on road crossing structures in Okaloosa darter streams to guide the closure/repair/maintenance of roads to contribute to recovery of the endangered species. In cooperation with Three Rivers RC&D Council, fish passage sites identified in the report were prioritized for restoration. 24. Monitored Aquatic Nuisance Species in the Apalachicola River and tested the sterility of exotic grass carp. 25. Multiple outreach projects were completed to detail aquatic resources conservation needs and opportunities. Participated in National Fishing Week event, several festivals, and school outreach.