441 resultados para 1345
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Geologic evidence along the northern part of the 2004 Aceh-Andaman rupture suggests that this region generated as many as five tsunamis in the prior 2000years. We identify this evidence by drawing analogy with geologic records of land-level change and the tsunami in 2004 from the Andaman and Nicobar Islands (A&N). These analogs include subsided mangrove swamps, uplifted coral terraces, liquefaction, and organic soils coated by sand and coral rubble. The pre-2004 evidence varies in potency, and materials dated provide limiting ages on inferred tsunamis. The earliest tsunamis occurred between the second and sixth centuries A.D., evidenced by coral debris of the southern Car Nicobar Island. A subsequent tsunami, probably in the range A.D. 770-1040, is inferred from deposits both in A&N and on the Indian subcontinent. It is the strongest candidate for a 2004-caliber earthquake in the past 2000years. A&N also contain tsunami deposits from A.D. 1250 to 1450 that probably match those previously reported from Sumatra and Thailand, and which likely date to the 1390s or 1450s if correlated with well-dated coral uplift offshore Sumatra. Thus, age data from A&N suggest that within the uncertainties in estimating relative sizes of paleo-earthquakes and tsunamis, the 1000year interval can be divided in half by the earthquake or earthquakes of A.D. 1250-1450 of magnitude >8.0 and consequent tsunamis. Unlike the transoceanic tsunamis generated by full or partial rupture of the subduction interface, the A&N geology further provides evidence for the smaller-sized historical tsunamis of 1762 and 1881, which may have been damaging locally.
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In this study, an attempt has been made to prepare the seismic intensity map for south India considering the probable earthquakes in the region. Anbazhagan et al. (Nat Hazards 60:1325-1345, 2012) have identified eight probable future earthquake zones in south India based on rupture-based seismic hazard analysis. Anbazhagan et al. (Eng Geol 171:81-95, 2014) has estimated the maximum future earthquake magnitude at these eight zones using regional rupture character. In this study, the whole south India is divided into several grids of size 1(o) x 1(o) and the intensity at each grid point is calculated using the regional intensity model for the maximum earthquake magnitude at each of the eight zones. The intensity due to earthquakes at these zones is mapped and thus eight seismic intensity maps are prepared. The final seismic intensity map of south India is obtained by considering the maximum intensity at each grid point due to the estimated earthquakes. By looking at the seismic intensity map, one can expect slight to heavy damage due to the probable earthquake magnitudes. Heavy damage may happen close to the probable earthquake zones.
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In this study, the idealized two-dimensional detonation cells were decomposed into the primary units referred to as sub-cells. Based on the theory of oblique shock waves, an analytical formula was derived to describe the relation between the Mach number ratio through triple-shock collision and the geometric properties of the cell. By applying a modified blast wave theory, an analytical model was developed to predict the propagation of detonation waves along the cell. The calculated results show that detonation wave is, first, strengthened at the beginning of the cell after triple-shock collision, and then decays till reaching the cell end. The analytical results were compared with experimental data and previous numerical results; the agreement between them appears to be good, in general.
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El presente estudio se realizó con los objetivos de la utilización del Anamú (Petiveria Alliaceae) en el tratamiento de la mastitis subclínica bovina en la finca San Emilio Comarca la Escoba, Municipio de Diriomo en el Departamento de Granada Latitud 11°83 ́3 ́ ́ Norte Longitud Este 85°98 ́3 ́ ́. El departamento de Granada limita al sur con Rivas, al norte con Granda y Boaco, al oeste con Carazo y Masaya y al Este con el Lago Cocibolca. En este trabajo experimental los análisis de varianza así como las estimaciones de los parámetros de cada factor fueron realizados con el Statical Análisis System (SAS) con una función de modelo lineal reducido con factores principales para dos respuestas de la variable dependiente diagnóstico de mastitis CMT, tomando en cuenta toda la población en producción lechera en ese momento. El tratamiento I: Solución de Anamú al 40%. Tratamiento II: Solución de Anamú al 20%. Tratamiento III: tratamiento testigo (Oxitetraciclina 200 mg, Bacitracina 250 mg, Neomicina 2 000 UI, y Prednisolona 10 mg). Existe una prevalencia del 39% con 43vacas infectadas con el 61 % resulto negativo a la prueba de CMT. Los tratamientos 1y 2 obtuvieron mejores resultados en el control y tratamiento de esta enfermedad que el tratamiento químico y a través del análisis de costos se determinó que es económicamente factible la utilización de la solución de Petiveria Alliaceae en el tratamiento de esta enfermedad.
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Integran este número de la revista ponencias presentadas en Studia Hispanica Medievalia VIII: Actas de las IX Jornadas Internacionales de Literatura Española Medieval, 2008, y de Homenaje al Quinto Centenario de Amadis de Gaula.
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Consultoria Legislativa - Área XIV - Comunicação Social, Informática, Telecomunicações, Sistema Postal, Ciência e Tecnologia.
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从耦合波方程出发,分别在小信号、高功率密度(1.5GW/cm^2)条件下研究了晶体串接三次谐波(THG)转换方案,并利用实验验证了该方案。实验观察到这种方案可以有效提高宽带激光三次谐波转换效率,但混频晶体之间的距离对宽带三次谐波转换效率影响明显。在1.5GW/cm^2平均功率密度下,实验中最佳距离25mm处,对带宽3.5nm的啁啾脉冲取得了19.75%的三倍频效率,这对于高功率激光宽带三次谐波转换的解决很有意义。
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多层介质反射镜在非正入射的时候,两个不同的偏振态之间会产生不同的相移.根据空气与膜层、膜层之间的实际情况,建立了界面层和表面吸附层模型,并运用它分析相位延迟产生误差的原因.通过优化设计,入射角为54°,在1285~1345nm之间p,s波获得了270±1°的相移,同时也使反射率在99.5%以上.用离子束溅射技术制备相位延迟膜,用分光光度计测试了光谱特性和用椭偏仪测试了相位特性,在相应波段获得了262.4±1.8°的相移,同时也使反射率在99.6%以上.误差的主要来源是离子源工作特性会产生不均匀的过渡层和最
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多层介质反射镜在非正入射的时候,两个不同的偏振态之间会产生不同的相移。利用矩阵法,根据菲涅耳公式和电磁场边界条件,推导出p,s波的相移。通过优化设计.入射角为54°,在1285~1345nm之间p,s波获得了270°±1°的相移,同时也使反射率在99.5%以上。用离子束溅射技术制备相位延迟膜,用分光光度计测试了光谱特性和用椭偏仪测试了相位特性,在相应波段获得了262.4°±1.8°的相移,同时也使反射率在99.6%以上。误差的主要来源是离子源工作特性会产生不均匀的过渡层和最外层会吸收一些水气、灰尘等也产生
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植物源挥发性有机碳化合物(Volitale organic compounds, VOC)是大气VOC的主要来源,与对流层大气质量、大气化学密切相关。鉴于温带草地的分布范围很广,草地植物VOC释放潜力某种程度上影响植物源VOC的总释放量。另外,植物源VOC也是光合作用固定碳素的损失方式之一,可能在特定区域或生态系统中具有重要意义。基于上述想法,本文设计了四个方面的实验作为研究内容:1) 温带草地物种水平VOC释放潜力、及其与植物功能群的关系?2) 沙地植物物种水平VOC释放潜力、及其与植物功能群的关系?3) 沙地植物-草地植物VOC释放潜力存在显著性差异吗?4) 温带典型草地和退化草地的VOC释放速率如何?在生态系统水平,植物源VOC对温带草地碳循环的贡献多大? 在所测定的175种温带草地植物中,不同植物间异戊二烯和单萜释放潜力差异很大;除少数物种外,大多数植物的异戊二烯和单萜释放潜力都较低,尤其是典型草地的优势物种。在此基础上,作者探讨了分类学赋值方法对温带草地植被的可行性,并初步建立了锡林河流域温带草地植物的VOC释放目录(共277种植物)。另外,温带草地植物的异戊二烯和单萜释放潜力与植物功能群(植物生活型和水分功能群)具有一定的联系,尤其是植物生活型。总的来说,温带草原的优势生活型(物种),即多年生根茎禾草(或多年生丛生禾草),具有较低的异戊二烯和单萜释放潜力。各水分功能群间差异不显著,但中旱生植物、旱中生植物 (温带草原的优势功能群),具有较低的异戊二烯、单萜释放潜力。因此,温带草原退化过程中,那些具有较高VOC释放潜力的植物,重要性将会增加。 沙地植物种类组成非常丰富,不同物种间的异戊二烯和单萜释放潜力变异也很大。另外,沙地植物的异戊二烯和单萜释放潜力与其功能群间关系较密切,不同植物生活型间差异显著;其中也以多年生根茎禾草、多年生从生禾草的释放潜力最低,而乔木的释放潜力相对最高;该结论基本与草地的研究结论一致。然而,沙地植物的异戊二烯和单萜释放潜力与其水分功能群的关系比较模糊,中生植物具有更高的释放潜力,湿生植物的释放潜力较小。 通过对比沙地植物和草地植物的释放潜力,发现沙地植物的异戊二烯和单萜释放潜力比草地植物高,且这种差异整体上显著。另外,这种显著性差异,在不同植物生活型、水分功能群间也同样存在。沙地植物比对应的草地植物具有更高的异戊二烯和单萜释放潜力,最可能的原因:沙地正午的温度明显比草地温度高,前者实测温度可超过 45 ℃,这种经常性、周期性高温,促使沙地植物采用与草地植物不同的适应策略,即沙地植物通过释放更多的异戊二烯或单萜来减少其可能遭的热胁迫或热伤害,这种长期适应策略,使沙地植物具有更高的萜类化合物释放潜力。 本文还调查了温带典型草地生态系统和退化草地生态系统的异戊二烯和单萜释放速率,结果表明典型草地的标准异戊二烯和单萜释放速率分别为0.50 μgC g-1 h-1和0.69 μgC g-1 h-1;退化草地的标准异戊二烯和单萜释放潜力分别为0.32 μgC g-1 h-1和1.59 μgC g-1 h-1。总的来说,温带草地的异戊二烯和单萜释放速率都比较低,尤其是典型草地。整个生长季,典型草地释放的异戊二烯和单萜分别为31.6 mgC•m-2 和 70.4 mgC•m-2;退化草地的异戊二烯和单萜释放量分别为20.8 mgC•m-2 和 168.8 mgC•m-2。退化草地萜类化合物总释放速率远高于典型草地,尤其是单萜释放能力。过度放牧引起的草地退化,通过改变植被种类组成,对温带草地的异戊二烯和单萜释放速率产生显著影响;总体而言,温带草地退化将会使草地释放更多萜类化合物。 在温带草地生态系统中,Clost as VOC相对其NPP而言很小,在环境PAR和温度高时,它的贡献率相对较大;Clost as VOC约占典型草地生态系统NEP的5.32 %,退化草地生态系统NEP的0.23 %。植物源VOC释放所损失的碳素相对草地生态系统NPP而言几乎可以忽略不计;但是,相对其NEP,Clost as VOC还是具有一定的相关性。虽然,草地生态系统Clost as VOC对NPP或NEP的贡献率较小,但考虑到全球尺度植物源VOC的巨大释放速率,它在碳循环中的贡献率仍然不容忽视;在某些特殊的生态系统中,仍可能扮演重要角色。