Adjoint-based Adaptation for the Correction Procedure via Reconstruction Method on Hybrid Meshes

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

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Bence-albee after 25 years: A new superior α-factor correction procedure for the quantitative analysis of oxides and silicates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133357 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1744-1745

Author(s):

John T. Armstrong

Keyword(s):

Quantitative Analysis ◽

Electron Microprobe ◽

Binary Systems ◽

Correction Procedure ◽

Geological Samples ◽

The Past ◽

Large Matrix ◽

Computational Speed ◽

Microprobe Data ◽

Geological Sciences

One of the most cited papers in the geological sciences has been that of Albee and Bence on the use of empirical " α -factors" to correct quantitative electron microprobe data. During the past 25 years this method has remained the most commonly used correction for geological samples, despite the facts that few investigators have actually determined empirical α-factors, but instead employ tables of calculated α-factors using one of the conventional "ZAF" correction programs; a number of investigators have shown that the assumption that an α-factor is constant in binary systems where there are large matrix corrections is incorrect (e.g, 2-3); and the procedure’s desirability in terms of program size and computational speed is much less important today because of developments in computing capabilities. The question thus exists whether it is time to honorably retire the Bence-Albee procedure and turn to more modern, robust correction methods. This paper proposes that, although it is perhaps time to retire the original Bence-Albee procedure, it should be replaced by a similar method based on compositiondependent polynomial α-factor expressions.

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Three-dimensional reconstruction of the 40S ribosomal subunit from rabbit reticulocytes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128961 ◽

1987 ◽

Vol 45 ◽

pp. 936-937

Author(s):

Neng-Yu Zhang ◽

Terence Wagenknecht ◽

Michael Radermacher ◽

Tom Obrig ◽

Joachim Frank

Keyword(s):

Three Dimensional ◽

Ribosomal Subunit ◽

Uranyl Acetate ◽

Reconstruction Method ◽

Single Exposure ◽

Electron Dose ◽

Ribosomal Subunits ◽

40S Ribosomal Subunit ◽

Dimensional Reconstruction ◽

Rabbit Reticulocytes

We have reconstructed the 40S ribosomal subunit at a resolution of 4 nm using the single-exposure pseudo-conical reconstruction method of Radermacher et al.Small (40S) ribosomal subunits were Isolated from rabbit reticulocytes, applied to grids and negatively stained (0.5% uranyl acetate) in a manner that “sandwiches” the specimen between two layers of carbon. Regions of the grid exhibiting uniform and thick staining were identified and photographed twice (magnification 49,000X). The first micrograph was always taken with the specimen tilted by 50° and the second was of the Identical area untilted (Fig. 1). For each of the micrographs the specimen was subjected to an electron dose of 2000-3000 el/nm2.Three hundred thirty particles appearing in the L view (defined in [4]) were selected from both tilted- and untilted-specimen micrographs. The untilted particles were aligned and their rotational alignment produced the azimuthal angles of the tilted particles in the conical tilt series.

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