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141.
Kunihiro T Miyazaki T Uramoto Y Kinoshita K Inoue A Tamaki S Hama D Tsutsumi H Ohwada K 《Marine pollution bulletin》2008,57(1-5):68-77
We monitored seasonal changes of the abundance and composition of microorganisms in the fish-farm sediment in Kusuura Bay, Amakusa, Japan, using the quinone profiling technique, during bioremediation by introducing cultured colonies of polychaete, Capitella sp. I. In November 2004, approximately 9.2 million cultured worms were transferred to the fish-farm sediment, which increased rapidly, and reached 458.5 gWW/m(2) (528,000 indiv./m(2)) in March 2005. During this fast-increasing period of Capitella, the microbial quinone content of the surface sediment (0-2 cm) also increased markedly, and reached 237 micromol/m(2) in January 2005, although the water temperature decreased to the lowest levels in the year. Particularly, the mole fraction of ubiquinone-10 in total quinones in the sediment, indicating the presence of alpha subclass of Proteobacteria, increased by 9.3%. These facts suggest that the bacterial growth was enhanced markedly by the biological activities of worms in the sediment, and the bacteria played an important role in the decomposition of the organic matter in the sediment. 相似文献
142.
The investigations were carried out at 6 tidal flats located on the eastern part of the Seto Inland Sea, Japan. This study was focused on physical characteristics of sediments, namely as particle size of sediment and difference in elevation, and generalizes the relationship between sediments and macrobenthos. A total of 192 species were collected at 187 stations at 6 tidal flats. Physical characteristics of sediment were classified into 9 groups by cluster analysis in relation to sediment particle size and difference in elevation. Those groups had also significant difference in physical characteristics of sediments, and were characterized by some specific macrobenthos species. Distribution of macrobenthos can be explained by the classification of physical characteristics of sediment. These findings show the possibility to predict the variety of macrobenthos community using the physical characteristics of sediment. 相似文献
143.
Variability in rainfall threshold for debris flow after the Chi-Chi earthquake in central Taiwan, China 总被引:6,自引:0,他引:6
The purpose of this study is to analyze variability in rainfall threshold for debris flow (critical rainfall for debris flow triggering) after the ML 7.3 Chi-Chi earthquake in central Taiwan in 1999. Two study sites with different geological conditions were surveyed in the earthquake area. Streambed surveys were conducted to continuously monitor debris flows between 1999 and 2006. During the 7-year study period, every debris flow event was identified, and the streambed characterized. Results show that the rainfall threshold for debris flow was remarkably lower just after the Chi-Chi Earthquake, but gradually recovered. To date, this rainfall threshold is still lower than the original level prior to the earthquake. This variability in rainfall threshold is closely related to the mount of sediment material in the initiation area of debris flow, which increased rapidly due to landslides resulting from the earthquake. With the increase in sediment material, the rainfall threshold was lowered severely during the first year following the Chi-Chi earthquake. However, heavy rainfalls mobilized the sediment material, causing debris flows and transporting sediment downstream. With the decrease in sediment material, the rainfall threshold recovered gradually over time. Furthermore, debris flows occurred only in the subbasins that had sufficient sediment material to cause significant movement. Hence, these results confirm that the sediment material in the initiation area of debris flow is a crucial component of the rainfall threshold for debris flow. 相似文献
144.
通过反演研究2008年日本岩手—宫城内陆地震(M~6.9),说明了用1Hz全球定位系统(GPS)观测数据推导中强震(M6级)震源过程的能力。比较了此次地震采样率为1Hz的GPS观测波形,发现与强震仪记录波形有很好的一致性。由于震源区及其周围有足够多的GPS台站很好地记录到了地面运动,因而使我们仅仅采用1Hz的GPS观测数据就可进行波形反演。反演的结果与大地测量和强震仪数据联合反演的结果相当一致,如地震矩(Mw~6.9)、累积滑动量分布和破裂传播等。这种一致性证明,采样率为1Hz的GPS观测数据不仅能用来推导M6级中强震破裂过程的动态特征,而且能用来推导其持久(或静态)的滑动。 相似文献
145.
147.
MATHEMATICAL MODELS FOR LIQUID-SOLID TWO-PHASE FLOW 总被引:2,自引:0,他引:2
Weiming Wu Sam S.Y. Wang National Center for Computational Hydroscience Engineering The University of Mississippi MS U.S.A. 《国际泥沙研究》2000,(3)
I INTRODUCTIONTurbulence models for single-phase fluid flows have been developed and widely applied in mechanical,aeronautical, environmental and hydraulic engineering, and other fields. The closure techniques for theReynolds-averaged Navier-Stokes equations for various levels of models including the simple turbulencemodel, one-equation turbulence model, k-s turbulence model and turbulence stress/flux model have beenverified to be physically reasonable and have acceptable accuracy in app… 相似文献
148.
华北东部地幔改造作用和置换作用:单斜辉石激光探针研究 总被引:14,自引:3,他引:11
对山东蒙阴古生代金伯利岩中石榴石方辉橄榄岩、河南鹤壁新生代玄武岩中 铬尖晶石方辉橄榄岩、山东栖霞新生代玄武岩中央晶石二辉橄榄岩和山东山旺新生代 玄武岩中尖晶石(富CpX)二辉橄榄岩单斜辉石的常量、微量元素的研究和对比表明:华 北地块古生代稳定存在的克拉通岩石圈地幔在中、新生代其东部被具大洋地幔性质的 显生宙地幔不均匀地发生了置换作用,残存于南北重力梯度带(岩石圈减薄过渡带)上 的鹤壁浅部克拉通地幔除保存有置换作用前改造作用的丰富信息外,也包含有其深部 被置换后的地幔改造作用信息;郯庐断裂带东部栖霞的新生地幔仍保留有较多的大洋 地幔成分特征,而郯庐断裂带内山旺的新生地幔受后续地幔改造作用的影响有向大陆 地幔演化的趋向.发生于华北地块东部中、新生代的岩石圈巨厚减薄作用与地幔的置换 作用有关,由渐进的富CO_2流体或碳酸岩熔体对岩石圈地幔的交代改造作用以及由此 所引起的熔体抽取作用是完成新生地幔对古老地幔置换作用的关键.郯庐断裂带等岩 石圈深大断裂为地幔改造作用和地幔置换作用提供了良好的通道作用. 相似文献
149.
目前 ,地幔对流脉冲的发生时间和大的火成岩区的活动越来越引起研究人员的注意 ,因为它们可能与地磁倒转频率、大陆漂移和全球气候等全球变化事件相一致。可能源自地幔基底的大面积地幔上涌被认为是超羽现象。分布在西太平洋的巨大海台 ,如翁通爪哇海台和Shatsky海岭都被认为是这种大火成岩区的产物 ,这些巨大海台最早于白垩纪中期出现在现在的南太平洋超隆起区。然而 ,由于板块构造运动 ,海洋中年龄超过150Ma的大的火成岩区在地球表面已不复存在。海台在大洋板块上被动地移动 ,其碎片可能在会聚板块边缘的加积棱柱中堆积成各种… 相似文献
150.
1IntroductionDuringthe past several years,concern hasincreasedover the potential pollution of watershed by estrogeniccompounds,including steroidal hormones fromhumanand ani mal sources.Effluents from wastewater treat-ment plants are sources of endocrine-d… 相似文献