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51.
泡沫铝的动态压缩性能和吸能性研究 总被引:9,自引:0,他引:9
通过测量泡沫铝在动态和准静态压缩条件下的应力 -应变曲线 ,研究了泡沫铝的准静态和动态压缩行为以及不同应变条件下的吸能性 ,并对其应变率效应进行了分析。结果表明 ,在高应变速率和准静态压缩下 ,泡沫铝的σ -ε曲线均表现出弹性变形段、平缓段和密实段三阶段特征 ;泡沫铝的压缩性能具有明显的应变速率敏感性 ,随应变速率的提高 ,流动应力上升 ,吸能性升高 相似文献
52.
《Drying Technology》2007,25(7):1175-1183
Although considerable progress has been made in the development of experimental techniques for investigating velocity distribution inside a fixed bed, these techniques were limited to special cases. Consequently, the velocity distribution is normally measured at downstream of the fixed bed and then this measurement is considered to be representative for the flow inside the bed. To evaluate the representativeness of this technique, this work presents a study of the change in the flow characteristics, starting from the boundary of the fixed bed within the pipe to a downstream position where the experimental measurement is taken, by using simulations based on computational fluid dynamics methods. 相似文献
53.
采用美国PDI公司开发的PDI-S软件,对不同缺陷基桩的反射波法低应变动测曲线进行数值模拟,对动测曲线的特征进行归纳与总结,以便在解释反射波法曲线时作为参考与借鉴,提高基桩质量检测的可靠度。 相似文献
54.
55.
E. Stenitzer H. Diestel Th. Zenker R. Schwartengräber 《Water Resources Management》2007,21(9):1567-1584
The performance of the water balance and crop growth model SIMWASER to estimate the water supply of a lawn by capillary rise
from shallow ground water was investigated by using lysimeter measurements with a sandy and a clayey soil. Moreover the robustness
of the model was evaluated by running it either with measured hydraulic soil parameters or with estimated pedotransfer functions
(PTFs) derived from texture and bulk density. Simulations were performed for the years 1996–1998 with input data from the
lysimeter station Berlin-Dahlem (Germany) for lysimeters containing undisturbed sandy or clayey soil monoliths, with groundwater
at 135 cm depth. Simulated evapotranspiration and percolation/capillary rise were in good agreement with the measured data
for all variants, while simulated soil water storage was acceptable only for the variants using hydraulic soil data based
on laboratory measurements or using PTFs derived from known soil class and bulk density. PTFs based on mean total pore volume
of the respective soil classes yielded soil water storages which were evidently too high; therefore they should be used with
care and must be avoided at all in simulating the soil water balance of arid sites with shallow groundwater. 相似文献
56.
57.
Power devices with high capability have been developed. 8‐kV/3.5‐kA‐class light‐triggered thyristors have the highest capability among power devices. These devices are used in the Kii Channel HVDC transmission system in Japan. In this paper, we report the extracted problems of conventional testing methods of 8‐kV/3.5‐kA‐class light‐triggered thyristors among manufacturers, and the proposed unified testing methods on the basis of element characteristics and operating conditions in the Kii Channel HVDC system. Furthermore, we propose a figure of merit for power devices for the practical use, and try to extract elements used at the Kii Channel HVDC system with small margins and low withstand capabilities. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 61–70, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10024 相似文献
58.
MV2000T智能变送器 总被引:1,自引:0,他引:1
较全面地介绍了ABB公司MV2 0 0 0T智能变送器的市场开发背景、工作原理、技术规格、性能特点及设计选型要点 相似文献
59.
石英砂脱水性能的研究 总被引:1,自引:0,他引:1
通过大量试验结果 ,研究了各种粒度范围的石英砂的脱水性能 ,包括沉降特性、过滤性能、极限压缩浓度等 ,为进行此类产品的固液分离提供了重要的参考数据 相似文献
60.
Stefan Kasapis 《International Journal of Food Science & Technology》2002,37(4):403-413
The structural properties of mixtures of pectin, oxidized starch and glucose syrup were investigated using small deformation dynamic oscillation. In the absence of added calcium, preparations of low methoxy pectin with glucose syrup formed viscous solutions, which remained crystal-free at subzero temperatures. Samples of oxidized starch and glucose syrup, on the other hand, exhibited solid-like behaviour because of the crystalline nature of the amylose-like helices. Mixtures of the two polysaccharides with the co-solute clearly showed phase inversion from liquid to solid-like behaviour with increasing amounts of starch in the formulation. The transformation was reflected in the textural properties of samples, which varied from thick solutions to firm gels. The viscoelasticity of the system was modified further by the introduction of high methoxy pectin. Preparations of high methoxy pectin and glucose syrup formed rubbery gels whose amorphous nature underwent a glass transition during cooling. 相似文献