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21.
在海原断裂带内部发现一个第三纪拉分盆地 ,命名为老龙湾拉分盆地。根据卫片解译结果和野外地质调查 ,对该盆地内的地层沉积序列、地层分布、相关断裂等特征进行了研究。结果表明 ,老龙湾拉分盆地发育于海原断裂内的最大斜列部位 ,盆地沉积受边界断裂控制 ;盆地内部沉积了巨砾岩、杂砾岩及紫红色 -灰绿色泥岩、桔红色角砾岩等地层 ,最大沉积厚度约 4 6 0 0m。老龙湾盆地内部地层不整合于不同的外围地层之上 ,根据对盆地内部沉积序列及外围第三系的区域对比 ,认为盆地沉积开始于中新世中期。由以上特征确定老龙湾盆地为海原断裂带内的第三纪拉分盆地。它为青藏高原东北缘第三纪的走滑断层活动的研究提供了地质证据 相似文献
22.
Green tides have occurred every year from 2007 to 2014 in the Yellow Sea. Ulva prolifera(Müller) J. Agardh has been identified as the bloom-forming alga,co-occurring with U. intestinalis. We observed distinct strategies for both algal species during green tides. U. prolifera exhibited a high abundance initially and then decreased dramatically,while U. intestinalis persisted throughout. The antioxidant system responses of these two macroalgae were compared in the late phase of a green tide(in-situ) and after laboratory acclimation. Lipid peroxidation and antioxidant system responses differed significantly between the two. Malondialdehyde and hydrogen peroxide contents increased significantly in-situ in U. prolifera,but not in U. intestinalis. In U. prolifera,we observed a significant decrease in total antioxidant ability(T-AOC),antioxidant enzymes(SOD and Apx),and non-enzyme antioxidants(GSH and As A) in-situ. U. intestinalis showed the same pattern of T-AOC and SOD,but its Gpx,Apx,and GSH responses did not differ significantly. The results suggest that U. prolifera was more susceptible than U. intestinalis to the harsh environmental changes during the late phase of a Yellow Sea green tide. The boom and bust strategy exhibited by U. prolifera and the persistence of U. intestinalis can be explained by differences in enzyme activity and antioxidant systems. 相似文献
23.
文章关注于产业、人口与资源环境要素的作用关系,建构了资源环境承载力综合评价框架,并以海南省为案例区开展应用研究。该框架首先对区域产业重要性进行评价并分级,为产业结构调整提供依据;其次解析了区域产业、人口资源消耗与污染排放强度,最后,基于产业评价结果设定不同的产业结构调整情景,结合产业和人口的资源消耗与污染排放强度评价不同产业结构下的资源环境承载力,即产业和人口的规模上限。结果表明:2016年海南省的经济规模并未超载,产业有进一步发展空间。其中土地资源成为海南省发展的首要限制因素,其次是水环境;海南经济效益较高的支柱产业和基础性产业多为高耗水、高污染的产业,亟需加强水资源的集约利用,并降低污染排放强度。为提升经济发展规模上限,需要培育低能耗、低排放的产业。文章建构的资源环境承载力评价方法将产业、人口与资源环境相联系,其评价结果政策意义更为明确,可为优化产业结构调整、控制产业及人口发展规模提供决策参考。 相似文献
24.
利用参考重力场模型基于能量法确定GRACE加速度计校准参数 总被引:1,自引:0,他引:1
利用多个参考重力场模型分别对GRACE一个月的实测加速度计观测数据进行检校。数值计算结果的比较分析表明了利用参考重力场模型确定加速度计校准参数是有效的。 相似文献
25.
26.
选取基础教育、社会保障、基本医疗、公共文化四大类指标,利用2008—2013年我国26个省份163个中小城市的统计数据,测度了其基本公共服务水平区域均等化程度的动态变化。结果表明:中小城市基本公共服务平均水平呈上升趋势;基础教育和基本医疗的区域均等化程度较好,社会保障和公共文化的区域差异较大;基本公共服务水平表现出空间集聚发展态势,东高西低的分布格局呈加剧之势。优化公共财政体制建设,加强省份间协同发展是促进基本公共服务均等化的重要途径。 相似文献
27.
Drought is one of the most complex natural hazards affecting agriculture, water resources, natural ecosystems, and society. The negative societal consequences of drought include severe economic losses, famine, epidemics, and land degradation. However, few studies have analyzed the complexity of drought characteristics, both at multiple time scales and with variations in evapotranspiration. In this study, drought occurrences were quantified using a new drought index, the Standardized Precipitation Evapotranspiration Index (SPEI), based on observed data of monthly mean temperature and precipitation from 1961 to 2013 in Henan province, central China. Based on the SPEI values of each weather station in the study, the frequency and severity of meteorological droughts were computed, and the monthly, seasonal, and annual drought frequency and intensity over a 53-year period were analyzed. The spatial and temporal evolution, intensity, and the primary causes of drought occurrence in Henan were revealed. The results showed that the SPEI values effectively reflected the spatial and temporal pattern of drought occurrence. As the time scale decreased, the amplitude of the SPEI increased and droughts became more frequent. Since 1961, drought has occurred at the annual, seasonal, and monthly scales, and the occurrence of drought has increased. However, regional distribution has been uneven. The highest drought frequency, 35%, was observed in the Zhoukou region, while the lowest value, ~26%, was measured in central and western Henan. The most severe droughts occurred in the spring and summer, followed by autumn. Annually, wide-ranging droughts occurred in 1966–1968, 1998–2000, and 2011–2013. The drought intensity showed higher values in north and west Henan, and lower values in its east and south. The maximum drought intensity value was recorded in Anyang, and the minimum occurred in Zhumadian, at 22.18% and 16.60%, respectively. The factors with the greatest influence on drought occurrence are increasing temperatures, the Eurasian atmospheric circulation patterns, and the El Niño effect. 相似文献
28.
调查的基础L,统计了太岳山种子植物有97科、316属、575种(含变种),分析了该区系的主要特征,即植物区系地理成分复杂,温带成分占优势;植物资源种类丰富,区系起源古老;植物区系具明显的过渡性;植被类型复杂,具明显的垂直分布.对该区野生经济植物进行了分类统计,为植物资源合理利用与生物多样性保护提供了基础资料穹科学依据. 相似文献
29.
古气候模式与现代气候模式控制因子不完全相同,有的因子在现代气候模拟中可以不考虑,但是在古气候模拟中则是必不可少的,例如轨道参数、大气中温室气体的浓度、大陆冰盖、大洋热盐环流等。而且,随着模拟的时间尺度不同,这些因子的作用也不同。评价古气候模拟,可以从3处着眼:气候变化的方向、幅度和速度。但是,长期以来古气候模拟仅仅涉及到前两个问题,也就是研究气候对外强迫的平衡响应。集其大成者是古气候模式比较计划(Paleaoclimate Modelling Intercomparison Project, 相似文献
30.
He-Jun Chai Jun-Jie Wang Sheng-Chuan Tang 《Geotechnical and Geological Engineering》2009,27(3):315-323
The visualization of rock structure is a very useful and important technique in many aspects in geological and geotechnical
engineering such as investigating and evaluating the stability of a high rock slope. The conventional method used to visualize
rock structure is limited to plotting the orientation of individual discontinuities by using the Schmidt stereographic net.
The present paper shows a new technique to visualize the three-dimensional structure of rock masses. The fitting function
for three-dimensional rock structure was established based on data gathered from field survey. Two fitting methods by which
the discontinuous points gathered from a plane and discrete points from field survey were fitted respectively are suggested.
The technique to visualize the three-dimensional structure of rock masses includes many aspects such as projection transformation,
blanking and mutual cutting, are investigated. Based on the visualizing technique, the rock structure at the site of Xilupdu dam which is being built in Southwest of China was investigated. 相似文献