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101.
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It has for many years been controversial whether there was a Pleistocene high sea level on the Shandong Peninsula. Our investigations in recent years suggest that the red sandy sediments distributed around the Yuanyaodun village, Weihai County, the "Liukuang Red Bed" and the loess-like deposits near Penglai County should be terrestrial deposits, and there is will not a convincing evidence to confirm that abrasion landforms found above the 10m elevation oa the coast are of marine origin. From these, it is still not safe to say that a high sea level had occurred in the Shandong Peninsula during the Pleistocene. 相似文献
103.
海洋环境荷载下输液立管的静、动力特性研究 总被引:1,自引:1,他引:1
考虑管内流动流体和管外海洋环境荷载共同作用 ,建立海洋立管侧向运动微分方程。用Hermite插值函数离散 ,在微机上编写海洋立管静、动力分析程序 ,通过计算分析研究管内流体对立管侧向变形和应力的作用 ;另外 ,探讨管内流体的流动速度和立管顶端的预张力对立管动力特性的影响。结果表明 ,立管变形和应力均随管内流体流动速度增加而增大 ,同时内流速度的增大会降低立管的固有频率 ,但适当增大立管顶端预张力会抵消内流流速增加引起的固有频率下降。 相似文献
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本研究采取苗种强化培育、坑道培育大规格苗种、湖间带鲍参混养等相结合,并配套适当技术措施,促进鲍快速生长,缩短养殖周期一年左右,提高成活率15%以上,增加经济效益200%左右,形成鲍高效养殖的较理想模式。 相似文献
105.
Large-scale field tests were conducted to study set-up effect in open-ended prestressed high-strength concrete pipe piles jacked into stratified soil. Four open-ended prestressed high-strength concrete pipe piles with 13 and 18 m in embedment depth were fully instrumented with fiber Bragg grating sensors and installed. Several restrike dynamic tests were performed on each test pile, with the time interval from 21.5 to 284 hours after installation. Static loading tests (SLTs) were later performed on each test pile at 408 hours after installation to substantiate the dynamic tests. Changes with time in pile bearing capacity and in the shaft and toe resistances were studied based on the results of the pile tests. The development of shaft resistance set-up in different layers was studied in particular. It was found that set-up effect in the shaft resistance is significant and the toe resistance increment was minor. The overall set-up factor of total bearing capacity was found to range from 0.09 to 0.53, and the set-up effect of friction pile is much larger than the end bearing pile. More significant set-up in shaft resistance was observed in fill and alluvium layer. The dimensionless set-up factor A for shaft resistance in marine deposits ranges from 0.5 to 1.43, and it contributes the most to the shaft resistance as the shaft resistance in marine deposits is higher. 相似文献
106.
Abstract The segmentation of flood seasons has both theoretical and practical importance in hydrological sciences and water resources management. The probability change-point analysis technique is applied to segmenting a defined flood season into a number of sub-seasons. Two alternative sampling methods, annual maximum and peaks-over-threshold, are used to construct the new flow series. The series is assumed to follow the binomial distribution and is analysed with the probability change-point analysis technique. A Monte Carlo experiment is designed to evaluate the performance of proposed flood season segmentation models. It is shown that the change-point based models for flood season segmentation can rationally partition a flood season into appropriate sub-seasons. China's new Three Gorges Reservoir, located on the upper Yangtze River, was selected as a case study since a hydrological station with observed flow data from 1882 to 2003 is located 40 km downstream of the dam. The flood season of the reservoir can be reasonably divided into three sub-seasons: the pre-flood season (1 June–2 July); the main flood season (3 July–10 September); and the post-flood season (11–30 September). The results of flood season segmentation and the characteristics of flood events are reasonable for this region. Citation Liu, P., Guo, S., Xiong, L. & Chen, L. (2010) Flood season segmentation based on the probability change-point analysis technique. Hydrol. Sci. J. 55(4), 540–554. 相似文献
107.
A new direct performance‐based design method utilizing design tools called performance‐spectra (P‐Spectra) for low‐rise to medium‐rise frame structures incorporating supplemental damping devices is presented. P‐Spectra are graphic tools that relate the responses of nonlinear SDOF systems with supplemental dampers to various damping parameters and dynamic system properties that structural designers can control. These tools integrate multiple response quantities that are important to the performance of a structure into a single compact graphical format to facilitate direct comparison of different potential solutions that satisfy a set of predetermined performance objectives under various levels of seismic hazard. An SDOF to MDOF transformation procedure that defines the required supplemental damping properties for the MDOF structure to achieve the response defined by the target SDOF system is also presented for hysteretic, linear viscous and viscoelastic damping devices. Using nonlinear time‐history analyses of idealized shear structures, the accuracy of the transformation procedure is verified. A seismic performance upgrade design example is presented to demonstrate the usefulness of the proposed method for achieving design performance goals using supplemental damping devices. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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钢-混凝土混合结构抗震研究述评 总被引:5,自引:4,他引:5
本文回顾了钢-混凝土混合结构的发展历史,系统地总结、论述了钢-混凝土混合结构的特点及其抗震研究发展现状,指出了这种结构形式在抗震研究中存在的主要问题和今后需要进一步研究的方向。 相似文献