ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02605.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYTheoretical stereological approaches to particle aggregates characteristically suppose that each particle is convex, so that upon sectioning, each particle gives rise to either 0 or 1 convex planar profile. Actually, the essential requirement in such approaches is that each planar section profile be connected; such particles need not be convex.In this paper, aggregates of quite general non‐convex particles, whose individual planar section profiles may thus comprise a number of disjoint connected regions, are considered. For this, it is necessary to anticipate the ultimate technical development of ultra‐sensitive devices (or other methods) capable of identifying in a planar section those disjoint connected regions stemming from the same particle. With this assumption, it is shown how, using the ‘4‐linc’—a new line section characteristic—to estimate the aggregate volume moment ratio, the standard isotropic section theory fully extends. To complete the picture, the recent development by Jensen&Gundersen of estimators foris extended to the ‘restricted’ case considered here. Allowing the particle volume distribution to belong to a two‐parameter family, these two parameters,Nvand the aggregate mean valuesm

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02606.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA stereological estimator of the weightedmean volume of particles of arbitrary shapeis described. This unbiased estimator is based on simple point‐sampling of linear intercept lengths. The complete absence of shape assumptions effectively breaks the long‐standing ‘convexity‐barrier’: the only requirement here is that individual particles can be unambiguously identified by their profiles on random sections. Practical details of the simple estimation procedure and an example with very irregular particles are reported. Finally, an estimator of the variance of the weighted distribution of particle volume is discussed. This estimator is also valid for particles of arbitrary shape. For any mixture of ellipsoids (spheres, oblates, prolates and triaxial ellipsoids) the estimator is reduced to a simple function of measurements of diameters in the sect

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02607.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYElements of surfaces that bound a phase (β) in a two phase mixture (α+β) may be classified as: (a) convex (++) if both principal curvatures are positive; (b) concave (− −) if both are negative; and (c) saddle (+ −) if one is positive and the other negative. This classification excludes the limiting cases for which one or both of the principal curvatures is zero. The traces of these surfaces that form the boundaries of the β areas on a representative two dimensional section may also be: (a) convex (+) if the local curvature is positive; or (b) concave (−) if it is negative. Line intercepts may be tabulated separately for intersections with convex (+) and concave (−) segments of boundary. This paper presents a derivation of fundamental stereological formulae that relate these counting measurements to three‐dimensional geometric properties of the struct

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02608.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThis paper describes an empirical method for the experimental assigning of specimens to a set of standard specimens. The procedure was developed especially for stochastic scenes. Typical applications of such a procedure are found in material sciences in assigning specimens to a standard series. The assignment is based on feature vectors obtained from analyses of the specimen texture by means of erosion or opening. In cases where the arrangement of particles is characteristic of the specimen, dilation or closing are used to obtain a feature vector. To increase the sensitivity of the method described the use of more than one structuring element is recommended in the analysis. Besides the classification of an unknown specimen the procedure provides information on the separability of the standard specimen and the significance of assignment.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02609.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYTechniques for characterizing the geometrical nature of rough surfaces by three‐dimensional descriptors are developed. Measurement of surface coordinates from SEM stereopairs by semi‐automatic stereometry is used to establish the raw data. The surface area, the distribution of size and angles of triangular surface facets, the anisotropy of surface geometry, and surface roughness parameters can be assessed by various computing algorithms. Some typical results obtained for fracture surfaces in a ceramic material are shown. Problems, alternative methods and future developments are discus

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02610.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe first section considers a packing of spheres with the same radius, whose contact zones are reduced to points. The numbernof contacts per unit volume is derived from the histogram of the closest distances between couples of discs induced on a plane section. The second section extends the results of the preceding one to the case of slight elasticity. The new formulae differ noticeably from the previous ones. Finally, the case of a population of spheres with different radii is treated, and the two previous approaches are generalized. Once more, two‐dimensional estimates of the 3‐D contacts are provi

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02611.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA non‐parametric stereological method for the estimation of distributions of distances (d) between paired spheres of the same size, from the distances between their profiles observed in sections, is presented. The model accounts for sphere overprojection and truncation effects.Using the mean value ofd (d̄), it is then possible, with simple formulae, to compute the probabilities of the co‐observation of two profiles from paired spheres with distancedbetween their centres, when at least one profile is observed.A useful application is the estimation of true binucleated cell frequencies from observations on tissue sections. An example for rat liver diploid cells is shown.The sphere distribution must be studied beforehand and, when the size variation is unacceptably large, implying that the assumption of a constant sphere radius is unreasonable, the main limitation of the model is

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02612.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe tandem scanning reflected light microscope has the property of being able to obtain information from ‘inside’ solid objects by taking a thin optical section at the focal plane of the objective lens. This plane can be focused up and down through the specimen.We describe an unbiased 3‐D counting rule for the TSRLM, which is applied to the estimation of osteocyte lacunar density in whole bone. This is shown to be an extremely efficient way of making such an estimate. Further possibilities for the application of the microscope in the field of stereology are disc

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02613.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYSpheres which are part of a spatial process are photographed. The relationship is derived between the sizes of the images and the actual sphere size distribution. Non‐orthogonal projection given by the linear optics of a pinhole camera is assumed. The depth of field is brought into the calculatio

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02614.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY