988 resultados para 126-789
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本文简要介绍了抚顺煤田的区域地质背景及受灾楼房调查结果,并对房屋建筑破坏特征进行了分析。同时,对大地测量结果、地质勘察及试验结果进行了讨论,结果表明:煤田开采诱发了浑河断裂抚顺段的局部活动。最后,综合分析得出断层活动引起的地基不均匀沉陷是造成该市建筑破坏的主要原因,且断层引起的地基不均匀沉陷不同于一般软基不均匀沉陷。
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特征分析表明:对原始扰动量的抛物化稳定性方程组(PSE),它在亚、超音速区分别具有椭圆和抛物特性,给出PSE特征对马赫数的依赖关系,阐明PSE仅把信息对流-扩散传播特性抛物化,而保留了信息对流-扰动传播特性,因此PSE应称为扩散抛物化稳定性方程(DPSE)。
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本文基于频率法进行损伤识别的基础,从理论上推导了损伤导致某阶频率降低与损伤位置的关系和该阶曲率模态/应变模态的振型变化相近。并通过数值仿真的结果验证了理论分析的结果。在此基础上给出了损伤状态下通过不同阶模态频率改变率比值来进行损伤定位的新方法,并将其应用于实际钢梁的分析中,得到了较好的结果。最后文中阐述了通过频率法进行损伤识别的优点和局限性。
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Número monográfico publicado bajo el título:" Mendia, gizartea eta kultura. Montaña, sociedad y cultura. Montagne, societé et culture".
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The objective of the study described here was to determine the effect on variable-leaf watermilfoil of various combinations of triclopyr concentrations and exposure times using dosage rates that controlled Eurasian watermilfoil under laboratory and field conditions (Netherland and Getsinger 1992, Getsinger et al. 1997, Petty et al. 1998).
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Helburuak: Liburu honek Gailuen Elektronika irakasgaian azken urteotan egin diren azterketak jasotzen ditu. Hortaz, ikasleek azterketak prestatzeko eta, oro har, elektronika ikasteko oso baliagarritzat jotzen dugu. Irakasgaiaren helburu nagusia diren oinarrizko osagaien ezaugarriak eta funtzionamenduaren printzipioak lantzen dira. Norentzat izan daiteke baliagarria: Testua Ingeniaritza Eskolako Lehenengo Ikasturteko ikasleentzat bereziki prestatu da, baina gailuen funtzionamendua eta anplikazio-sistema sinpleak aztertzen dituzten ariketak jasotzen dituenez, oso baliagarria gerta daiteke, orobat, edozein maila eta titulazioko Elektronika-ikasleentzat -edota ikasle horiei irakatsi behar dietenentzat.
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As defined, the modeling procedure is quite broad. For example, the chosen compartments may contain a single organism, a population of organisms, or an ensemble of populations. A population compartment, in turn, could be homogeneous or possess structure in size or age. Likewise, the mathematical statements may be deterministic or probabilistic in nature, linear or nonlinear, autonomous or able to possess memory. Examples of all types appear in the literature. In practice, however, ecosystem modelers have focused upon particular types of model constructions. Most analyses seem to treat compartments which are nonsegregated (populations or trophic levels) and homogeneous. The accompanying mathematics is, for the most part, deterministic and autonomous. Despite the enormous effort which has gone into such ecosystem modeling, there remains a paucity of models which meets the rigorous &! validation criteria which might be applied to a model of a mechanical system. Most ecosystem models are short on prediction ability. Even some classical examples, such as the Lotka-Volterra predator-prey scheme, have not spawned validated examples.
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Validated by comparison with DNS, numerical database of turbulent channel flows is yielded by Large Eddy Simulation (LES). Three conventional techniques: uv quadrant 2, VITA and mu-level techniques for detecting turbulent bursts are applied to the identification of turbulent bursts. With a grouping parameter introduced by Bogard & Tiedemann (1986) or Luchik & Tiederman (1987), multiple ejections detected by these techniques which originate from a single burst can be grouped into a single-burst event. The results are compared with experimental results, showing that all techniques yield reasonable average burst period. However, uv quadrant 2 and mu-level are found to be superior to VITA in having large threshold-independent range.
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Escritos publicados de 18 de junho a 2 de julho de 1906, no Jornal do Commercio, sob o título Em prol da verdade, respondendo a uma critica do Sr. Gumersindo Bessa à Réplica do Amazonas no litígio pendente com a União acerca do Acre Setentrional.
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IN this paper, the engraving process with Q-Switched Nd:YAG laser is investigated. High power density is the pre- requisition to vapor materials, and high repetition rate makes the engraving process highly efficient. An acousto- optic Q-Switch is applied in the cavity of CW 200 W Nd:YAG laser to achieve the high peak power density and the high pulse repetition rate. Different shape craters are formed in a patterned structure on the material surface when the laser beam irradiates on it by controlling power density, pulse repetition rate, pulse quantity and pulse interval. In addition, assisting oxygen gas is used for not only improving combustion to deepen the craters but also removing the plasma that generated on the top of craters. Off-focus length classified as negative and positive has a substantial effect on crater diameters. According to the message of rotating angle positions from material to be engraved and the information of graph pixels from computer, a special graph is imparted to the material by integrating the Q- Switched Nd:YAG laser with the computer graph manipulation and the numerically controlled worktable. The crater diameter depends on laser beam divergence and laser focal length. The crater diameter changes from 50 micrometers to 300 micrometers , and the maximum of crater depth reaches one millimeter.
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This report summarizes the results of a characterization of chemical contaminants in the sediments in southwest Puerto Rico. The report is part of a project to integrate various analytical specialties to assess linkages between chemical contaminants and the condition of coral reefs. In this phase of the project, over 120 chemical contaminants were analyzed in sediments collected, including a number of organic (e.g., hydrocarbons), inorganic (e.g., metals), and biological (bacterial) compounds/analytes. The report also provides a preliminary analysis of the association between sediment contaminants and coral species richness. Overall, the levels of chemical contaminants in the study area between Guanica Bay and the town of La Parguera were fairly low. At most of the sites sampled, particularly adjacent to the town of La Parguera, concentrations of organic and inorganic contaminants were below the median values from NOAA’s National Status and Trends Program, which monitors the Nation’s coastal and estuarine waters for chemical contaminants. Elevated levels of a number of contaminant classes were seen at the two sites sampled within Guanica Bay. An initial analysis of modeled PAH (hydrocarbon) data and coral species richness (reef building species) indicated a strong negative correlation between the presence of PAHs in the sediments and coral species richness. Additional work is needed to assess possible reasons for this observed pattern. (PDF contains 126 pages).