共查询到18条相似文献,搜索用时 312 毫秒
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本文通过基于Visual basic的非织造布计盒维数的测定,发现非织造布的分形特征,并通过实验研究了非织造布透通性与分形维数的关系,得出对同一类型的非织造布,孔隙分形维数越高,其透通性越好的结论。 相似文献
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非织造材料孔隙结构的定量表述 总被引:4,自引:1,他引:3
利用计算机图像处理技术,提取了孔隙尺寸、孔隙形状和纤维取向分布等直观表达非织造纤维材料结 构的参数;利用新的几何学———分形几何,对非织造纤维材料的孔径分布情况进行分析,获得孔径分 布分形维数。在此基础上研究纤维网单位面积质量和特征长度对纤维网结构的影响,以及孔径分布 分形维数与通透性能之间的关系。 相似文献
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根据涤纶短纤针刺非织造材料的孔隙具有的分形特点,通过建立其纵向几何结构模型,介绍了一种利用分形分析求解针刺非织造材料水平渗透率的方法,进而预测有关非织造材料的水平渗透系数。 相似文献
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非织造材料基本结构特征的表达 总被引:1,自引:0,他引:1
介绍了非织造材料基本结构特征的表达方法,即从纤维在集合体中的排列与取向、孔隙结构的几何描述和集合体构造的均匀性等3方面来表征,并提出应用分形维数对非织造材料的孔径分布进行表征的新方法。 相似文献
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Multiple fractal features estimated by box-counting method are applied to fabric defects detection with a view to getting over the difficulty encountered in tasks of textures differentiating using only one single fractal feature. Extraction of the optimum multiple fractal features is based on the following fact that has been observed for the first time: when box-counting method is adopted to estimate the fractal dimension of an image or a data series, the involved measuring box size series have a considerable influence on the estimated fractal dimension and in turn the ultimate value of the separability between normal samples and defective ones. Testing results indicate that, using the proposed algorithm, actual false alarm probability and missing rate can be controlled simultaneously below 10% under an appropriate range of threshold, proving with confidence the effectiveness of the fractal features extracted in this study. 相似文献
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《Journal of food engineering》2008,84(4):570-580
The development of a relationship between microstructural changes of model food products (carrot and potato cubes) and their physical changes during conventional hot air drying (HAD) using combined fractal and image analysis was performed in this study. Dried carrot and potato sections were examined by light microscopy and the fractal dimension (FD) of the microscopic images was determined using a box counting technique. The apparent physical changes of the samples undergoing HAD were represented in terms of the percentage of shrinkage and rehydration ratio. These apparent changes correlated well with their microstructural changes represented by the normalized changes of fractal dimension (ΔFD/FD0) of the microstructural images. Although the microstructural changes of the samples undergoing HAD were quite different, the changes of ΔFD/FD0 of the samples undergoing drying were in the same trend. FD has thus proved to be a good indicator of microstructural changes of products undergoing drying. 相似文献
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针对羊毛纤维集合体结构特征往往难以得到有效表征这一问题,将分形的概念引入羊毛纤维集合体的结构表征,利用计盒维数的方法,计算了5种不同质量的羊毛纤维集合体的分形维数,同时采用平板式保温仪测定了羊毛纤维集合体的保暖性能;随后定量关联了羊毛纤维集合体的分形维数与其基本结构参数和保暖性指标之间的关系。结果表明:利用分形维数来表征纤维集合体的结构特征是可行的,随羊毛纤维质量和体积分数的增大,集合体的分形维数增大,这说明集合体中的纤维结构更杂乱;随分形维数增大,集合体的克罗值和保温率增大,而传热系数减小,即纤维集合体的保暖性增强。 相似文献
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利用分形理论求解织物渗透率 总被引:1,自引:0,他引:1
介绍了一种利用织物的分形分析解模型求解织物渗透率的新方法。该模型是根据织物的孔隙结构具有分形特点,建立起渗透率与织物的分形维度、织物结构参数之间的函数,从而预测织物的渗透率。以平纹织物为例,对纱线的结构模型进行改进,使其更准确地求解出织物的渗透率。 相似文献
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为对梗丝形态差异性进行评价,通过测量单一形态梗丝周长、面积并采用“小岛法”计算其分形维数及形态指数,以叶丝形态为标准,选取梗丝与叶丝分形维数及形态指数的差异为指标,建立梗丝形态差异性系数模型及评价方法并验证分析。结果表明:①单一形态梗丝拟合方程决定性系数R2均达到0.850,且均方差及残差均较小,表明“小岛法”可准确计算其分形维数。②梗丝形态具有分形特性且不同形态梗丝分形维数具有明显差异,随着分形维数逐渐增大梗丝形态越来越不规则。③所建梗丝形态差异性系数模型$Y_e=4.825 X_{D_i-D^{\prime}}-1.149 X_{\bar{K}-\bar{K}^{\prime}}+0.320$,决定性系数R2达到0.948,F检验达到显著水平表明回归模型具有统计学意义,且模型经验证准确可靠。④初步建立了一种梗丝形态差异性评价方法,以差异性系数e为指标,梗丝形态间差异性小(e≤0.491);较小(0.491 < e≤0.813);适中(0.813 < e≤1.189);较大(1.189 < e≤1.565);大(e > 1.565),该方法可通过定量指标实现对梗丝形态差异性的定性分析。 相似文献