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31.
32.
桶形基础沉贯室内模型试验研究 总被引:3,自引:0,他引:3
桶形基础采用负压沉贯法施工,其贯入阻力与压桩,打桩等施工方法显著不同。本文介绍了在粉土和粉质粘土地层中的一组模型试验情况,认为负压法施工可显著降低粉土的抗贯阻力,但在粉质粘土中减阻效果不明显。 相似文献
33.
If the upstream boundary conditions are prescribed based on the incident wave only, the time-dependent numerical models cannot effectively simulate the wave field when the physical or spurious reflected waves become significant. This paper describes carefully an approach to specifying the incident wave boundary conditions combined with a set sponge layer to absorb the reflected waves towards the incident boundary. Incorporated into a time-dependent numerical model, whose governing equations are the Boussinesq-type ones, the effectiveness of the approach is studied in detail. The general boundary conditions, describing the down-wave boundary conditions are also generalized to the case of random waves. The numerical model is in detail examined. The test cases include both the normal one-dimensional incident regular or random waves and the two-dimensional oblique incident regular waves. The calculated results show that the present approach is effective on damping the reflected waves towards the incident wave boundary. 相似文献
34.
We propose a bio-optical inversion model that retrieves the absorption contributions of phytoplankton and colored detrital matter(CDM),as well as the phytoplankton size classes(PSCs),from total minus water absorption spectra.The model is based on three-component separation of phytoplankton size structure and a genetic algorithm.The model performance was tested on two independent datasets(the NASA bio-Optical Marine Algorithm Dataset(NOMAD) and the northern South China Sea(NSCS) dataset).The relationships between the estimated and measured values were strongly linear,especially for aCDM(412),and the Root Mean Square Error(RMSE) of the CDM exponential slope(SCDM) was relatively low.Next,the inversion model was directly applied to in-situ total minus water absorption spectra determined by an underwater meter during a cruise in September 2008,to retrieve the phytoplankton size structure in the seawater.By comparing the measured and retrieved chlorophyll a concentrations,we demonstrated that total and size-specific chlorophyll a concentrations could be retrieved by the model with relatively high accuracy.Finally,we applied the bio-optical inversion model to investigate changes in phytoplankton size structure induced by an anti-cyclonic eddy in the NSCS. 相似文献
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36.
以HDR隔震梁桥多自由度(MDOF)模型和等效双线性单自由度(SDOF)模型为研究对象,以典型近场地震动作为输入,研究HDR支座双向耦合效应对HDR隔震梁桥地震响应的影响。研究结果表明:不考虑双向耦合效应的HDR支座滞回曲线呈典型双线性;考虑双向耦合效应的HDR支座滞回曲线面积小于不考虑双向耦合效应的HDR支座滞回曲线面积。不考虑双向耦合效应的顺桥向HDR支座位移峰值db大于考虑双向耦合效应时,但横桥向的结果相反。近场地震作用下,对梁桥进行HDR支座隔震设计时,忽略双向耦合效应计算得到的墩底剪力峰值和弯矩峰值均偏于保守。可忽略HDR支座双向耦合效应对HDR隔震梁桥近场地震能量的影响。 相似文献
37.
用土的分形结构确定土的水份特征曲线 总被引:4,自引:4,他引:4
运用筛析法和比重计法,分析了宁夏膨胀土的颗粒分布,发现粒径介于0.002~0.1mm的粒度分布是分形的,分维介于2.46~2.67;运用上孔隙分布的分维确定水份特征曲线,得到了很好的结果。此外,还探讨了粒度分形分布的机制。 相似文献
38.
ABSTRACT The Ganjiang River is the largest tributary of Poyang Lake in China, and its hydrological regime variation greatly affects the utilization of regional water resources and the ecological environment of the lake. In this study, a novel trend analysis method, the Moving Average over Shifting Horizon (MASH), was applied to investigate the inter- and intra-annual trends of flow and water level from 1976 to 2016 at the Xiajiang and the Waizhou hydrological stations in the Ganjiang River. The Significant Change Rate Method (SCRM) was proposed to determine the MASH averaging parameters. The trend analysis results show a statistically significant decrease in water level series throughout the year and the relationship of flow and water level have changed greatly at the Waizhou station. The sediment load reduction, large-scale sand mining and water level decrease of Poyang Lake are identified as the main causes for the water level decrease. 相似文献
39.
Zhang Kaikai Mai Kangsen Xu Wei Zhou Huihui Liufu Zhiguo Zhang Yanjiao Peng Mo Ai Qinghui 《中国海洋大学学报(英文版)》2015,14(3):541-548
Journal of Ocean University of China - This study was conducted to investigate the effect of dietary proline (Pro), and Pro and hydroxyproline (Hyp) in combination on the growth performance, total... 相似文献
40.
大地热流测量数据子库 总被引:6,自引:0,他引:6
大地热流数据子库是建立在Microsoft Access 97基础上,以Microsoft Visual Basic 6.0开发、基于Windows平台上的集数据储存、编辑、报表打印输出及基本数据解释处理于一体的数据库管理软件.具有运行速度快、操作简单、易学及可靠性强等优点.特别编制了强大的数据查询系统,提供了各种查询方式,大大方便了用户. 相似文献