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21.
Linux主要发行版纵览 总被引：1，自引：0，他引：1
高巍 《数字社区&智能家居》2007,2(8):430-432
开源运动的蓬勃发展,催生出纷繁多样的Linux发行版本。本文收集了当前国内外几大主流Linux发行版本的最新信息,通过概括性的介绍,以帮助读者从中作出选择。 相似文献
22.
Qingchun Wang Zijie Fan Liangjin Gui 《International Journal of Mechanical Sciences》2007,49(4):515-521
A theoretical analysis was performed to predict the crushing behaviour of aluminium foam-filled single hat and double hat sections subjected to axial compression. The experimental results and superfolding element theory were used to create deformation models for the aluminium foam contained in the hat sections, and several assumptions were made for the theoretical analysis. According to the energy method and superfolding elements theory, the mean crushing force and the interactive effect were theoretically predicted for the axial compression of the aluminium foam-filled hat sections. The final formula specified the relationship between the mechanical characteristics of the aluminum foam and the height of the superfolding element. The mean crush forces and the interactive effect predicted by the theoretical analysis were in good agreement with the experimental results. The theoretical prediction results showed that the interactive effect was mainly from the aluminium foam. 相似文献
24.
This paper aims to explore the dynamic responses and crashing characteristics of double hat shaped tubes made of weave carbon fiber reinforced plastic (CFRP). Experimental investigations were carried out into three different thicknesses and lengths of the composite tubes fabricated by the bladder molding process. Three distinct failure modes, classified as progressive end crushing, mid-length collapse and overlap opening, were observed in the dynamic crushing tests. Unlike continuous splaying fronds observed in the quasi-static tests, dynamic tests exhibited a number of fragment segments in the progressive end crushing mode. It is shown that the ply number was a critical parameter affecting the failure mode and energy absorption capability. The increase in ply number led to increases in the peak load and specific energy absorption (SEA); whereas the tubal length seemed insensitive to energy absorption capability. Compared to the quasi-static cases, the dynamic impact tests resulted in the higher peak load (increased from 46 % to 125 %) and lower SEA (reduced from 21 % to 33 %) for the tested tubes. 相似文献
25.
针对柔性直流系统直流侧短路故障诊断难题,文章从故障网络精确建模和暂态特征信号分析两个方面展开研究,并提出了阻抗网络暂态响应时频特性关联度的故障诊断方法。该方法通过向柔性直流系统线路入口处注入脉冲电压作为激励,实时提取所产生的暂态电流分量,经不同尺度的Mexican Hat变换得到时频能量序列,并构造反映故障网络暂态响应时频能量谱矩阵。同时,建立柔性直流系统精确模型,模拟不同故障点经不同大小电阻的短路故障,构建完整故障样本及其时频特征库,经相似度计算可选出与实测故障特征最相近的样本,确定故障点位置和估计短路电阻大小。最后,对上述原理方法进行算例分析,并与时域方法比较,结果表明文章所述诊断方法及其判据更为准确有效,相关原理正确可行。 相似文献