共查询到19条相似文献,搜索用时 93 毫秒
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探索了一种对多孔高吸水性树脂的孔结构进行定量表征的研究方法。在用扫描电镜(SEM)对发泡法制备的多孔高吸水性树脂的孔结构进行表征的基础上,将SEM照片转换为灰度图像,利用体视学中的禁线法则和德莱塞定律,通过关联测格覆盖得到了多孔高吸水性树脂的孔面积、孔周长、孔隙率等结构参数。在此基础上,利用分形几何的研究方法,得到了多孔高吸水性树脂的分形维数与形状因子等参数。通过所建立的表征方法,讨论了不同致孔剂加入量对多孔高吸水性树脂结构的影响。 相似文献
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为考察多孔颗粒材料内孔表面分形特征及与其保水性能的关系,构建了多孔颗粒物内孔表面分维测算数学模型,并基于高精度扫描电子显微镜系统测算了4种多孔颗粒样品的内孔表面分维,测量了材料保水性能。结果表明:多孔颗粒的内孔表面的分维值介于2.088 2~2.193 5之间,且分形拟合曲线相关系数大于0.98,强的相关性说明内孔表面具有显著的分形特征。进一步研究发现,多孔颗粒材料保水性能与其内孔表面分维呈负相关。 相似文献
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《功能材料》2016,(Z1)
以NaCl-Na_2CO_3为熔盐介质制备了镁橄榄石多孔材料,采用压汞法研究了材料内部气孔的结构特征,利用SEM表征了材料的显微结构;采用综合热分析仪分析孔的形成机理,并在Menger海绵体构造模型的基础上,用分形理论对材料的孔径参数进行表征;研究了烧成温度与原料中盐配比对气孔分形维数的影响,探讨了气孔的分形维数与孔径分布的关系。结果表明,制备的镁橄榄石多孔材料内部气孔以6.6和66μm为界点,具有三重分形特征,其原因是材料内部气孔的成孔机理不同。原料配比中NaCl和Na_2CO_3的含量都为20%,经1 100℃烧后材料内部气孔的体积分形维数最小,为2.16895;此时材料内部孔径集中分布于6.6~66μm。 相似文献
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分维在超细粉末团聚状态表征中的应用 总被引:2,自引:0,他引:2
用激光和X射线小角散射实验研究超细粉末团聚体的结构,发现分形形态是粉末团聚体的普遍特征。提出了团聚体结构的分维表征,分析了分维与团聚状态及粉末工艺性能间的关系。 相似文献
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The mechanical behaviours of Ti-24Al-11Nb alloy in the brittle-ductile transition (BOT) have been investigated by using three-point bending tests. The temperature dependence of the fractal dimensions and fractal characterization of fracture surfaces are presented. The probable mechanism controlling BDT of intermetallic alloys are proposed according to fractal geometry.Additionally. it is found that there is a positive relationship between the fractal dimension and fracture toughness in BDT for Ti-24Al-11Nb alloy 相似文献
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M. L. Lyamshev 《Technical Physics Letters》2000,26(8):713-715
The thermooptical excitation of sound in a liquid by fluctuating laser radiation with sine-modulated intensity is studied theoretically. The intensity is randomly distributed over the beam cross section. It is assumed that the random processes are homogeneous and that the spatial spectrum of intensity fluctuations obeys a power fractal law. Possibilities for the optico-acoustic characterization of the fractal radiation structure of a laser with unstable resonator are discussed. 相似文献
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S.K. Sharma 《Journal of Modern Optics》2013,60(10):849-853
In problems relating to light propagation in soft biomedical tissues, the tissue is generally modeled as a turbid medium. In one of the often used models, the suspended scatterers have been assumed to be of spherical shape following a fractal size distribution law. This paper studies the relationship between scattering phase function features of tissue and the fractal dimension within the framework of a fractal tissue model. It is demonstrated that witin the framework of this model the measurement of scattering phase function at two or three near-forward angles can be employed to infer fractal dimension of the model tissue. This method for tissue characterization therefore could be a potentially useful method for early detection of cancer of soft tissues. 相似文献
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Peng Zhang Fuguo Li School of Materials Science Engineering Northwestern Polytechnical University Xi an China 《材料科学技术学报》2009,(6)
The characterization of reinforcement in 15% SiC particles reinforced Al matrix composites processed by powder metallurgy route was studied by statistical method. During the analysis, a new approach for the estimation of the characterization of reinforcement was presented. The mathematic software MATLAB was used to calculate the area and perimeter of reinforcement, in which the image processing technique was applied. Based on the calculation, the fractal dimension, shape factor, reinforcement size distribut... 相似文献
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Buzio R Malyska K Rymuza Z Boragno C Biscarini F De Mongeot FB Valbusa U 《IEEE transactions on nanobioscience》2004,3(1):27-31
The nonstationary character of roughness is a widely recognized property of surface morphology and suggests modeling several solid surfaces by fractal geometry. In the field of contact mechanics, this demands novel investigations attempting to clarify the role of multiscale roughness during physical contact. Here we review the results we recently obtained in the characterization of the contact mechanics of fractal surfaces by depth-sensing indentation. One class of experiments was conducted on organic thin films, load-displacement curves being acquired by atomic force microscopy using custom-designed tips. Another class of experiments focused on well-defined crystalline and mechanically polished ceramic substrates probed by a traditional nanoindenter. We observed the first-loading cycle to be considerably affected by surface roughness. Plastic failure was found to dominate incipient contact while contact stiffness increased on decreasing fractal dimension and roughness. Our findings suggest fractal parameters to drive contact mechanics whenever the penetration depth is kept below the interface width. 相似文献