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分析了反射式光纤涡街流量计在管道内流体的流动为层流和紊流时光纤的受迫振动,分析表明在层流和条流状态下,光纤所受张力与单位光纤长度的质量比满足T/ρ>>(0.4vD/d) ̄2时,光纤的振动及反射回到光纤的光强变化只与外力变化频率有关。实验结果已证实了本文分析的正确性。 相似文献
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硅氧烷表面活性剂是一类很有特色的表面活性剂,它们不仅在水溶液中而且在有机溶液中都表现了很高的表面活性。该类产品合成路线多样、品种繁多,逐渐取得了广泛的应用。本文将系统地介绍这类表面活性剂的制备、性能和应用。 相似文献
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本文结合生产实际,从原料选择,工艺流程及设备,各工序工艺设计及要求等,对特强聚酯缝纫线纺纱生产工艺进行了探讨. 相似文献
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J. Mecke 《Statistics》2013,47(2):201-210
In this paper we investigate the distribution of the periodogram, respectively, the periodogram matrix for stationary random sequences. These .distributions are consid¬ered in the case of a fixed frequency as well as in the case of a finite number of frequencies for Gaussian sequences and for sequences of independent random variables. The exact distribution is obtained in the case of a fixed frequence for one-dimensional GAUSsian sequences. Asymptotic expansions, respectively, the rate of convergence to the asymptotic distribution are given in the case mentioned above 相似文献
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高性能纤维的低温等离子体表面改性 总被引:1,自引:0,他引:1
陈惠敏 《南通工学院学报(社会科学版)》1999,15(1):41-44
本文介绍了用于纤维材料的低温等离子体表面改性技术,并对其在高性能纤维表面粘着性改善中的应用进行论述。 相似文献
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对几只弹力织物试样进行测试 ,采用一些数学方法对织物性能进行分析 ,为这一类织物的设计和服装选料提供参考依据 相似文献
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Estimation of Wood Fibre Length Distributions from Censored Data through an EM Algorithm 总被引:1,自引:0,他引:1
INGRID SVENSSON SARA SJÖSTEDT-DE LUNA LENNART BONDESSON 《Scandinavian Journal of Statistics》2006,33(3):503-522
Abstract. An expectation maximization (EM) algorithm is proposed to find fibre length distributions in standing trees. The available data come from cylindric wood samples (increment cores). The sample contains uncut fibres as well as fibres cut once or twice. The sample contains not only fibres, but also other cells, the so-called 'fines'. The lengths are measured by an automatic fibre-analyser, which is not able to distinguish fines from fibres and cannot tell if a cell has been cut. The data thus come from a censored version of a mixture of the fine and fibre length distributions in the tree. The parameters of the length distributions are estimated by a stochastic version of the EM algorithm, and an estimate of the corresponding covariance matrix is derived. The method is applied to data from northern Sweden. A simulation study is also presented. The method works well for sample sizes commonly obtained from increment cores. 相似文献