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951.
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The vortex-induced vibrations (VIV) of barrel-shaped mast are calculated by three numerical methods, i.e. Newmark-b, HPD-L (High Precision Direct integration scheme-Linear form), and HPD-S (High Precision Direct integration scheme-Sinusoidal form). According to the measured value, the accuracy curves are given to show the advantages of HPD-S method over others. Based on the comparison above, HPD-S method is used to calculate the influence of ice covering on the mast to VIV responses. It has been proved that the vortex-induced responses of barrel-shaped mast are changed along with ice thicknesses and types. 相似文献
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应急地理信息整合平台系统架构初探 总被引:3,自引:2,他引:3
多源应急地理信息在突发事件处置和应急事务管理中起着重要作用.本文设计了一种面向跨地区跨部门应急地理信息整合和应用集成的软件体系架构,介绍了主要技术路线,在此基础上开发了应急地理信息整合平台软件原型系统,并在应急管理实践中得到了成功应用. 相似文献
956.
诸侯经济、一体化经济还是不完全一体化经济?——论珠三角区域发展之路 总被引:3,自引:0,他引:3
就区域发展模式与战略选择而言,诸侯经济和一体化经济是两个重要方面,前者强调城市个体经济增长,后者注重区域统筹发展.通过对珠三角地区经济发展历程回顾,检视两种区域发展模式的优缺点.其次,对一体化经济模式进行深刻反思,认为完全一体化经济虽能实现区域整体利益最大化,但可能导致地方自主性丧失,滋生更大区域内的空间极化和区域隔离.文中提出区域经济发展的不完全一体化的发展模式,主张有选择性的空间封闭,下放发展权力给地方或区域\"社区\",既保持城市开放,也延续地方发展自主权.最后,从外部性理论、\"新区域主义\"和\"权力下放\"等西方区域发展新理论、珠三角发展实践等三方面对不完全一体化的可能性进行论证. 相似文献
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通过计算全球1951~2008年100hPa、500hPa高空资料、74项大气环流特征量、地面气压、太平洋海温以及中国160个测站的降水、气温等6种环流场和特征值与雨季开始期的相关性,找出了雨季开始期变化的高影响关键区,对关键区进行因子合成,筛选出了5种环流场的33个关键因子,分析因子的最佳界值和正贡献指数,经线性回归计算,建立分类环流一次预报方程和综合环流多因子集成预报二次方程,最后通过二次方程和正贡献指数方程建立三次集成预报模型,投入实际气候预测应用,4年来准确预测了玉溪雨季开始期。 相似文献
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本文提出了利用快速Hartley变换(FHT)计算Stokes公式的方法,这-算法最适合于用来计算实序列的积分变换,而快速Fourier变换(FFT)较适合于用来计算复序列的积分变换。计算Stokes公式只涉及实序列问题,用FHT计算Stokes公式比用FFT算法更有效。本文详细地描述了用FHΥ计算Stokes公式的算法,进行了数值计算,与相应的FFT计算结果作了比较。结果表明,两种算法可以得到相同的精度,但是,FHT的计算速度比FFT的计算速度快-倍以上,且所需要的内存空间只是后者的-半。 相似文献
959.
Geophysical techniques can help to bridge the inherent gap that exists with regard to spatial resolution and coverage for classical hydrological methods. This has led to the emergence of a new and rapidly growing research domain generally referred to as hydrogeophysics. Given the differing sensitivities of various geophysical techniques to hydrologically relevant parameters, their inherent trade-off between resolution and range, as well as the notoriously site-specific nature of petrophysical parameter relations, the fundamental usefulness of multi-method surveys for reducing uncertainties in data analysis and interpretation is widely accepted. A major challenge arising from such endeavors is the quantitative Integration of the resulting vast and diverse database into a unified model of the probed subsurface region that is consistent with all available measurements. To this end, we present a novel approach toward hydrogeophysical data integration based on a Monte-Carlo-type conditional stochastic simulation method that we consider to be particularly suitable for high-resolution local-scale studies. Monte Carlo techniques are flexible and versatile, allowing for accounting for a wide variety of data and constraints of differing resolution and hardness, and thus have the potential of providing, in a geostatistical sense, realistic models of the pertinent target parameter distributions. Compared to more conventional approaches, such as co-kriging or cluster analysis, our approach provides significant advancements in the way that larger-scale structural information contained in the hydrogeophysical data can be accounted for. After outlining the methodological background of our algorithm, we present the results of its application to the integration of porosity log and tomographic crosshole georadar data to generate stochastic realizations of the detailed local-scale porosity structure. Our procedure is first tested on pertinent synthetic data and then applied to a field dataset collected at the Boise Hydrogeophysical Research Site. Finally, we compare the performance of our data integration approach to that of more conventional methods with regard to the prediction of flow and transport phenomena in highly heterogeneous media and discuss the Implications arising. 相似文献
960.
This paper investigates the numerical performance of the generalized trapezoidal integration rule by using an advanced soil model. The generalized trapezoidal integration rule can include many other integration algorithms by adjusting a single parameter α ranging from 1 to 0. The soil model used is the recently developed middle surface concept (MSC) sand model which simulates different soil response characteristics by using different pseudo‐yield functions. The generalized trapezoidal rule and MSC sand model are used to simulate the responses of sand samples with different relative densities under various initial and loading conditions. Instead of a single step, multiple loading steps bring the sample to the vicinity of failure. These comprehensive investigations examine and compare the influences of various values of α on the numerical solution of integrated constitutive equations, the convergence of Newton's iterative scheme, and the integration accuracy. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献