数字图像技术辅助陶瓷显微组织定量分析研究

以古瓷釉显微组织为例,利用显微图像各组元的灰度特性,运用数字图像技术中的图像滤波、图像分割、轮廓提取方法对显微组织图像进行预处理,获取瓷釉组元分离图.在系统构成的基础上,结合体视学方法,对显微组织体积密度(Vv)、表面积密度(Sv)等体视学参数进行计算机分析与测量,为研究陶瓷材料及陶瓷内在结构与外观关系提供了可靠的技术支持和数据基础.     

金属多晶体晶粒的空间及截面拓扑分布特性

利用系列截面法系统地研究了一种微合金化低碳钢奥氏体晶粒的空间及截面拓扑分布特性.实验建立了晶粒界面数F与其截面多边形边数均值$\\bar n$及边数平方均值${\\bar n^2}$之间的经验关系,并进一步研究了不同拓扑级别的三维晶粒的截面拓扑分布且与多种晶粒几何模型进行了比较分析.     

The problem of ambiguous profiles of microvilli between apposed cell surfaces: a stereological solution

When interdigitating microvilli projecting from apposed cell surfaces are sectioned randomly, it becomes impossible to specify to which of the two parent surfaces an individual microvillous profile belongs. Because of this image ambiguity, direct estimation of the ratio of microvillous surface areas by intersection counting cannot be performed. A stereological solution to this problem is proposed. It relies on counts of the numbers of bases of microvilli identified on each reference (parent) surface.     

Efficient embedding technique for preparing small specimens for stereological volume estimation: zebrafish larvae

Stereological sampling regimes, in particular volume and number estimation, often require systematic uniformly random sections throughout a specimen. A method has been developed to increase the efficiency of preparing fish larvae for sectioning prior to histological or stereological analysis. Embedding a group of larvae in a resin block using this technique greatly reduces the quantity of sections produced and allows easy assessment of sample groups. Saving time in this way therefore makes stereology a more viable research tool.     

Estimating the total number of lymphatic valves in infant lungs with the fractionator

The fractionator is illustrated by means of a biomedical example involving the estimation of the number of lymphatic valves in lungs of infants who had died from sudden infant death syndrome (SIDS) and other known causes. The method is unbiased irrespective of tissue deformations and it does not require external information such as section thickness. An upper bound of the coefficient of error of the estimate of the number of valves within one lung was 6.5%, despite the fact that the number of valves counted per lung at the last stage ranged between 11 and 37 only. The upper bound includes the biological variation of the number of valves among infant lungs. Some theoretical remarks are also made on the efficiency of the fractionator. It is suggested, for instance, that the initial sampling stages cause more impact on the precision of the final estimator than the subsequent stages, and that an optimal arrangement of fragments submitted to systematic sampling should have the smallest fragments at the ends, with fragment contents increasing smoothly toward the middle of the series.     

Shape modelling of spatial particles from planar central sections – a case study

In this paper we develop statistical tools for shape modelling of spatial particles from central sections through the particles. The particles are assumed to be star‐shaped with respect to a reference point inside the particles and are modelled as stochastic deformations of spheres centred at the reference points. The resulting particles are rotation invariant with respect to the reference point. As an illustration, the model is applied to study shape differences between neurons in the Granular and CA1 layer in the human hippocampus.     

Application of Stereology on Neodymium-Doped Yttrium Aluminum Garnet （Nd： YAG） Transparent Ceramics

Nd ： YAG precursor powders were synthesized by homogeneous precipitation, and Nd ： YAG transparent ceramics were prepared by vacuum sintering at 1700 ℃ for 5 h. The ceramic materials were characterized by light transmittance and field emission gun-environment scanning microscope. Using statistics and stereology theory, study was carried out on the quantitative relationships between light transmittance and stereological parameters in three-dimensional Euclidean space. It is found that the transmittance of Nd：YAG with 1 mm in thickness is about 45% and 58% in visible and near-infrared wavelength, respectively. The transmittance linearly increases with increasing equivalent sphere diameter and reaches the theoretical value of single crystal when the equivalent sphere diameter is 20μm. The transmittance decreases with the increasing of mean specific area per unit volume of grain and discrete grains, and the transmittance decreases with increasing mean free distance of grains in Nd：YAG ceramics.     

Stereological analysis of the spatial Poisson–Voronoi tessellation

Stereological model tests and parameter estimators for the spatial Poisson–Voronoi tessellation are discussed. The tests aim to discriminate the Poisson–Voronoi tessellation from more regular or more irregular tessellations. The power of the model tests under some special parametric alternative hypotheses is investigated by simulation. Among the tests considered, the most powerful test is based on the variance of the section cell areas. Various stereological estimators for the model parameter of the spatial Poisson–Voronoi tessellation are compared with respect to their bias and variance by means of a Monte–Carlo study. Formulae are given for variance prediction. An estimator based on vertex counting is found to be the best. Robustness is investigated by applying the estimators to Voronoi tessellations generated by other point process models.     

用立体学方法和计算机图像分析技术计算水稻叶片的叶绿体几何参数

本文介绍用立体学方法和计算机图像分析技术定量地测量计算不同叶绿素含量的水稻叶片内叶绿体几何参数;用透射电镜方法得到叶绿体超薄切片的图像负片,用OMNICON3600型图像分析系统对电镜负片上的叶绿体图像做面积和周长的测量;用立体学方法公式计算出叶绿体的体积密度和表面积密度。结果表示:1,随叶绿素含量的增大,叶绿体的体积密度和表面积密度也随之增大,其原因是由于叶绿体的数量增多所致,这一结果目前在国内外尚未见报道。2,计算机图像分析技术对于测量大量的不规则图形的速度和精度远高于网格板方法,而且是一种测量超微结构图像几何数据的实用技术和量具。     

Stereology in Materials Science

Quantitative analysis of populations having ageometric structure,which has developed into aspecial scientific subject called microstructology orstereology,is of great importance to thecharacterization and evaluation of microstructuresand their evolution in various processes.This paper,besides a brief discussion on those topics such as therecent developments of computer assisted imageanalysis,mathematical morphology,and fractalanalysis,will mainly focus on the scope,fundamen-tals,present status,and perspectives of classicalstereology.Several case examples of its applicationto materials science will also be given.