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971.
Blubber samples of Baikal seals pups (Phoca sibirica) collected in 2001 and 2002 were analyzed for persistent organochlorines (OCs) such as PCBs (polychlorinated biphenyls), DDTs (dichlorodiphenyltrichloroethane and its metabolites), HCHs (hexachlorocyclohexane isomers), CHLs (chlordane related compounds), TCPMe [tris(4-chlorophenyl)methane] and TCPMOH [tris(4-chlorophenyl)methanol]. The distribution pattern of OCs was in the following order: DDTs>PCBs>CHLs>HCHs>TCPMOH>TCPMe. Organochlorine concentrations and composition patterns in eight pup blubber samples (2002) analyzed in the present study were compared with the corresponding levels in juvenile Baikal seals from 1992 survey, and it was found that residue levels of OC compounds have declined during the 10 year period. In particular, concentrations of PCBs, HCHs and CHLs in seals collected in 2002 were approximately two times lower, while DDTs levels were three times lower than the corresponding levels in 1992. Furthermore, higher ratios of beta-HCH/HCHs and p,p(')-DDE/DDTs were found in 2002 samples. While comparing the OC levels with those in other seal pups it appeared that all the OC concentrations were lower than the levels in seals from coastal California known as one of the most polluted areas. PCB and DDT concentrations in the present specimens were higher than that in Arctic seal pups. The proportions of tri-, tetra-, penta- and hexachlorobiphenyls in pups captured in 2002 were higher than those in 1992. TEQ concentrations of non- and mono-ortho coplanar PCBs in Baikal seals collected in 2002 were higher than those in seals collected from some locations in the world, where human and industrial activities are extensive, suggesting potential for toxic implications of coplanar PCBs in Baikal seals. 相似文献
972.
使用2002年M7.9阿拉斯加迪纳利断层地震(DFE)周围的地震形变和无震形变的观测资料,检验了余滑应该伴有颤动的假设。余滑比自发慢滑动发生得更频繁,而且已在更广泛的构造环境中观测到了。因此,伴随余滑的颤动存在与否能提供有关颤动生成的新线索。我们还搜寻了前兆颤动,即假定加速滑动导致破裂的证据。我们的搜寻在迪纳利断层地震前5天及其后3个月内的几个时段均未得到颤动。这种否定结果和一系列其他观测结果,或许都可用破裂穿透到假定的闭锁区以下到达摩擦过渡区内来解释。尽管并非独一无二,但这种解释确证了先前巨大逆冲断层和转换断层地震破裂完全延展到过渡区的模型。 相似文献
973.
974.
The Cimmerian terrane forms an almost unbroken chain stretching >13,500 km, from central southern Europe to western Indonesia, via SE Europe, the Middle East, Afghanistan, Tibet, SW China and Myanmar. Ar-guably, it is Earth’s most spectacular example of a “sliver” terrane, dwarfing in size more recently devel-oped examples, for instance the Palawan Block in the western Philippines, and the Lord Howe Rise in the Tasman Sea. The presentation will first outline the in-triguing geological features associated with this unique tectonic entity. Following that, recently obtained results following paleomagnetic investigations of two lower Permian rift-related basalt suites will be summarized (Abor Volcanics in northeastern India and Woniusi Ba-salts in Yunnan, China). The two studies are part of a larger programme of ongoing research aimed at deducing (I) the geodynamic configuration that generated the un-usual rifting system, and (II) exactly how Cimmeria fit-ted against Gondwana prior to its dispersal in the Early Permian. The critical unit is Baoshan, which we fit against Gondwana within a narrow longitudinal belt close to where northern India and northwestern Australia were once in close proximity (Fig. 1). Furthermore, we suggest that Sibumasu lay to directly the east, offshore of Australia; Qiangtang and Lhasa almost certainly sat to the west (off northern Greater India-SE Arabia), but we are uncertain as to their exact configuration. Our findings will be compared with several rather different models that have been published in recent years. The new pa-leomagnetic constraint highlights the flexibility authors currently have in reconstructing the region, principally because of the overall lack of similar high-quality data from the various blocks. We explain how new data could resolve these ambiguities, thereby offering more robust explanations for eastern Gondwana’s late Paleozoic de-velopment. 相似文献
975.
Reliable field data for all hydrologic parameters are often unavailable for watersheds even for those intensively monitored.In the absence of reliable such data,verified mathematical relations for an area can be used for other areas with same hydrologic and climatic regimes.The objectives of this research were:1) to assess the total runoff and sediment loss,and 2) to develop rainfall,runoff and soil loss relations for four prominent landuses(including degraded,pasture,forest and agriculture lands) in the Hilkot watershed(Pakistan).Four experimental natural runoff plots were established on the landuses (degraded,pasture,forest and agriculture land).The field study and data collection were conducted in the Hilkot watershed from 1999 to 2005.Regression analysis was conducted to establish relations among rainfall,runoff and soil loss for all landuses using.Regression analysis indicated good correlation with field data. 相似文献
976.
This paper investigates the phenomena of turbulent bursting events,and to make a comparative study among the events in the scour geometry developed by short circular cylinders of fixed length with different diameters placed on the sand bed transverse to the flow.The distributions of turbulent kinetic energy(TKE),turbulent diffusion in both longitudinal and vertical directions at different locations of scour marks,and the contributions of burst-sweep cycles to the Reynolds shear stress are presented. 相似文献
977.
2011年3月11日,一次Mw9.0大地震袭击了日本东北的太平洋沿岸,随后沿着500kin长的海岸线产生了巨大的破坏性海啸。此后,在2011年4月11日发生了一次M7.0内陆余震,这次余震造成了陆地上地表断层出现破裂。这些地震在日本本州岛东北部造成了各种类型的滑坡灾害。地震造成的全部滑坡灾害尚在调查统计之中。这份简短的报告介绍了日本滑坡学会迄今为止调查到的一些滑坡现象。这些滑坡包括:(1)福岛县须贺川水库堤坝的失稳;(2)4月11日福岛县磐城镇余震造成的滑坡及地震地表破裂;(3)宫城县松岛湾密集分布的浅表破坏;(4)仙台市周边居民区一些人工改造斜坡上发育的小滑坡。 相似文献
978.
979.
化学方法改良吹填土固结沉降性质研究 总被引:1,自引:1,他引:0
大连市大窑湾港区的吹填土为高分散性低液限粉质黏土,其特点是亲水性高,含水量大,排水率低,这造成了吹填土承载力低,在荷载作用下变形量大,在很长一段时间内无法作为正常建筑地基使用.通过在盐水环境下添加不同剂量的浓度为0.1%的絮凝剂Praestol-2515或Praestol-650溶液,可以观察到土颗粒迅速聚合,土粒粒径明显增大,粒间胶结更加均匀和紧密,形成絮状物,从而促进了土颗粒与自由水分的分离,导致过饱和吹填土(悬浊液)沉降速度大大提高,极大地缩短了吹填土的排水固结时间,在短期内达到建筑地基所需要的变形量和承载能力.研究结果对于沿海地区过饱和吹填土的造陆工程,以及类似的高含水率黏性土的地基处理具有重要的启示意义. 相似文献
980.
由郭荣星教授撰写的《跨边界资源管理(第二版)》(英文名:Cross-Border Resource Management-Second Edition",由荷兰Elsevier出版社于2012年出版;网络版:http://www.sciencedirect.com/science/bookseries/14748177/10)是一本系统阐述在跨边界地区或是边界过渡地区对自然与环境资源如何有效管理的学术专著。在跨边界地区,政府行为和管理手段是复杂的,司法权通常受制于两个或以上的独立政权或行政/军事势力影响。本书的作者对跨边界地区的地理、政治、法理、社会、经济学以及文化多个问 相似文献