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31.
The object of study is a stationary Gaussian white noise excited multi-degree-of-freedom (MDOF) linear elastic, ideal plastic, linearly damped, statically determinate oscillator with several potential elements of ideal plastic yielding. Specifically the study is exemplified for a plane multistory shear frame with rigid traverses where all the connecting columns except the columns in one or more of the bottom floors have finite symmetrical yield limits. The white noise excitation acts on the mass of the first floor making the movement of the elastic bottom floors simulate a ground motion that interacts with the structure above the bottom floors. The method of study is so-called Slepian model simulation and is in principle the same for other statically determinate MDOF elasto-plastic oscillators of the considered type. The method is fast as compared to direct simulation and provides results that give good insight in the behavior of the plastic displacement response process. 相似文献
32.
本工作用XRD,EPMA,SEM等测试技术计算和示出了用不同活性粉料制备的Ba(Mg1/3Ta2/3)O3微波陶瓷晶格中B位离子有序度和元素的面分布情况,对它们在X面下的电行为作了探讨。实验结果表明,BMT陶瓷的微波损耗主要与其密度有序度和微观结构的均一度有关。 相似文献
33.
鄱阳湖流域水土流失加剧了洪涝灾害。治理水土流失能增强山丘地涵养水源的能力,削洪减沙,减少库容损失,降低河床,具有明显的防洪效益。进行流域防洪规划时,应将防治水土流失与防洪治涝结合起来,因地制宣,综合治理。 相似文献
34.
本文在Knockout交换结构的基础上,探讨一种新的ATM交换结构,使其本身带有优先权控制功能,以适应不同业务对信元丢失率及时延的不同要求。这种结构既能最大限度地有效利用系统资源,又能满足不同用户对业务质量的不同要求,并能降低交换结构复杂度。 相似文献
35.
The magnetic properties of polyethersulfone-matrix composites with 3-19 vol.% polycrystalline nickel filaments (0.4 (im diam)
were investigated. These filaments were found to exhibit hysteresis energy loss 10800 J/m3 of nickel and coercive force 16.9 kA/m, compared to corresponding values of 4930 J/m3 and 4.7 kA/m for 2 μ.m diam polycrystalline nickel fibers, 1020 J/m3 and 0.5 kA/m for 20 μm diam polycrystalline nickel fibers, and 1280 J/m3 and 2.3 kA/m for solid polycrystalline nickel. 相似文献
36.
MPC系统模块结构中的流场研究 总被引:5,自引:0,他引:5
本研究中,应用Simple数值计算方法开发了求解MPC系统模块结构中二维流场分布的计算软件。为了验证计算结果的精确性,用多普勒测速仪实测了用有机玻璃制成的MPC模块二维模型的流场,模拟计算结果与实测值对比取得了较好的一致性。四种不同流出角的MPC模块平均总压损失计算结果表明,已开发的软件可作为设计低流阻MPC模块的良好工具。 相似文献
37.
38.
Rates of ammonia (NH3) loss from a ryegrass sward measured using a system of small wind tunnels were compared with concurrent measurements made using a micrometeorological mass balance method. Measurements were made during two experiments within a circular plot (radius 10m) treated with urea at a rate of 200kgNha?1. In the first experiment, air speed through the tunnels was adjusted as necessary to maintain a value of approximately 1ms?1. This value differed on most occasions from the mean ambient wind speed which was measured at a height of 250mm and which ranged from 0.61 to 2.95ms?1. Rates of loss measured using the wind tunnels differed by a factor of between two and five from those measured using the mass balance method; there was no consistent pattern in the differences between the rates of loss. The total losses of NH3 measured during 15 days were equivalent to 49.1 and 30.2kg Nha?1 for the mass balance and wind tunnel methods, respectively. In the second experiment, air speed through the tunnels was adjusted as necessary to maintain a value as close as possible to the mean ambient wind speed measured at a height of 250mm. Rates of NH3 loss measured using the two methods did not differ significantly; total losses of NH3 during 17 days were equivalent to 96.9 and 101kg Nha?1 for the mass balance and wind tunnel methods, respectively. The difference between the findings of the two experiments could be attributed to the direct effect of air speed through the tunnels rather than to differences between ambient temperatures and those inside the tunnels. During and following periods of rain the rates of loss measured using the tunnels were up to six times greater than those observed with the mass balance method. Rates of loss measured by the two methods became similar again when the tunnels were moved following rain. The study demonstrates that enclosures can be designed and operated to provide reliable measurements of the rate of NH3 loss from grassland. Potential applications of the two methods are discussed. 相似文献
39.
热带城市垃圾典型组分的热解特性研究 总被引:7,自引:0,他引:7
对热带城市垃圾的几种典型组分进行了热解实验,得到了它们的失重曲线,通过对失重曲线进行分析,得到了这几种典型组分的热解规律,并通过建立热解动力学模型,求出了其中两种组分的活化能E和频率因子A。 相似文献
40.