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91.
运用扫描电镜(SEM)和X-射线衍射(XRD)技术研究了电化学脱盐处理对钢样-砂浆界面微观结构的影响。试验结果表明,经电化学脱盐处理后,钢样-砂浆界面的微观形貌特征与组成发生了明显的变化。 相似文献
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The effects of different lateral confinement stress on the fatigue behavior of and cumulative damage to plain concrete are investigated experimentally. Eighty 100 mm x 100 mm x 100 mm specimens of ordinary strength concrete are tested under constant- or variable-amplitude fatigue loading and lateral confinement pressure in two orthogonal directions. A fatigue equation is developed by modifying the classical Aas-Jakobsen S-N equation for taking into account the effect of the confined stress on fatigue strength of plain concrete. The results of variable-amplitude fatigue tests indicate that the linear damage theory proposed by Palmgren and Miner is unreasonable in the biaxial stress state. A nonlinear cumulative damage model that could model the effects of the magnitude and sequence of variable-amplitude fatigue loading and lateral confinement pressure is proposed on the basis of the evolution laws of the residual strains in the longitudinal direction during fatigue tests. The residual fatigue life predic 相似文献
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The source and significance of two nutrients, nitrogen and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay, in autumn 2004. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrient supplied through remineralization by microzooplankton. The results indicated that the phytoplankton net growth rate increased in turn from inside the bay, to outside the bay, to in the Xiaogang Harbor. The phytoplankton maximum growth rates and microzooplankton grazing mortality rates were 1.14 and 0.92 d-1 outside the bay, 0.42 and 0.32 d-1 inside the bay and 0.98 and 0.62 d-1 in the harbor respectively. Outside the bay, the remineralized nitrogen (Kr=24.49) had heavy influence on the growth of the phytoplankton. Inside the bay, the remineralized phosphorus(Kr=3.49) strongly affected the phytoplankton growth. In the harbor, the remineralized phosphorus (Kr=3.73) was in larger demand by phytoplankton growth. The results demonstrated that the different nutrients pools supplied for phytoplankton growth were greatly in accordance with the phytoplankton community structure, microzooplankton grazing mortality rates and environmental conditions. It is revealed that nutrient remineralization is much more important for the phytoplankton growth in the Jiaozhou Bay than previously believed. 相似文献
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2004年10月至2005年8月,对不同季节千岛湖蚤状潘的垂直分布情况以及昼夜迁移进行了研究。结果表明,蚤状潘在千岛湖分布广泛,春季和夏季蚤状潘主要分布在15-25m水层,而在秋冬季分布相对均匀,从表层到60m水深都有分布;比较了蚤状漫在不同季节的迁移现象,春季和秋季蚤状潘为夜间迁移模式,而在夏季和冬季虽然都存在迁移现象,但不同于常见的三种迁移模式。 相似文献
99.
Recruitment patterns of Serpula vermicularis L. (Polychaeta, Serpulidae) in Loch Creran, Scotland 总被引:1,自引:0,他引:1
Nicola D. Chapman Colin G. Moore Dan B. Harries Alastair R. Lyndon 《Estuarine, Coastal and Shelf Science》2007,73(3-4):598-606
This study aimed to contribute to conservation management of reefs of Serpula vermicularis by increasing understanding of the factors influencing larval settlement. The study was carried out in Loch Creran, which supports the most extensive known development of S. vermicularis reefs in the world. Settlement plates were deployed to examine the influence of season, depth, reef density, substrate type and orientation. Monthly deployment of plates revealed settlement of S. vermicularis to occur predominantly from mid-June to mid-October, peaking in late August to early September. Settlement of Pomatoceros spp. peaked much earlier, in late May to early June. Deployment of plates at different depths revealed a marked reduction in S. vermicularis settlement intensity between 6 and 12 m. As this corresponds with the deeper limit of the peripheral fringe of serpulid reefs in the loch, it is suggested that this limit is imposed by a depth-correlated settlement response, rather than reduction in available substrata. Comparisons of various substrata showed a preference by S. vermicularis larvae for a slate over a scallop substrate and no evidence of enhanced recruitment to occupied or unoccupied tubes of S. vermicularis, suggesting that gregarious attraction is unlikely to be a factor causing reef formation. Settlement onto the upper side of a horizontal scallop substrate was found to be insignificant in comparison with the underside or a vertically orientated scallop. Evidence for the role of light in controlling the depth and substrate-orientation preferences of S. vermicularis larvae is discussed. Based on the results of this study, recommendations are made regarding remediation of areas suffering reef damage. 相似文献
100.
通过对目前生态动力学模型的总结和综合,以生态系统中氮、磷营养盐循环为主线,建立了适用于海洋围隔浮游生态系统的多变量的营养盐迁移-转化动力学模型.该模型包括浮游植物、浮游动物、溶解无机态营养盐、溶解有机态营养盐和生物碎屑5个模块,涉及溶解无机氮、磷酸盐、溶解有机氮、溶解有机磷、浮游植物、浮游动物和生物碎屑7个状态变量.分别利用1999年秋季和2000年夏季胶州湾围隔生态实验数据进行了模型和验证工作,成功地模拟了富加营养盐条件下围隔浮游生态系统中氮、磷营养盐生物化学迁移-转化过程,并确定了20余个参数的量值. 相似文献