ISSN:0049-8246    

DOI:10.1002/xrs.1300110102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractA simple scheme is described whereby x‐ray absorption spectra, including the very strong rapidly varying structure near an absorption edge, may be calculated using only a short program and small amounts of computer time. The analysis also provides general rules for the existence of strong structures at the edge. The scheme can describe any neutral absorbing atom (or, with a little modification, ion) and includes the effect of the core hole when necessary. Fits to experiment show good agreement near absorption edges, with somewhat poorer agreement far from the edge. The method is of use in obtaining absorption spectra for use in crystal spectrometers for x‐ray mirror calculations where a knowledge of the fine detail of the absorption is not necessary, but an accurate reproduction of the major structure near the edge

ISSN:0049-8246    

DOI:10.1002/xrs.1300110103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractAn accurate, rapid and relatively cheap method adapted for use in the phosphate industry for on‐line simultaneous multielement analysis of phosphate ore and calcined phosphate, using x‐ray fluorescence, is described. The method of analysis is sufficiently accurate for the phosphate industry, which demands great accuracy in P2O5analysis. A statistical evaluation of precision and accuracy is gi

ISSN:0049-8246    

DOI:10.1002/xrs.1300110104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe shape of energy dispersive diffraction lines from flat powder samples is determined by the Bragg angle, beam divergences, absorption of the radiation, specimen misalignment and detector performance. Due to asymmetric line broadening, the lines appear to be shifted, usually to lower energies. Two ‘specimen transparency models’ are presented, based upon the accurate determination of line positions and line intensities that are possi

ISSN:0049-8246    

DOI:10.1002/xrs.1300110105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractPhase transformation studies as well as the determination of linear expansion coefficients are used to show characteristics, accuracy and methods of data evaluation in energy dispersive x‐ray diffractometry. A high temperature chamber was modified to withstand temperatures up to 2300°C with fixed angle geometry. Observation of phase transformations in time frames of 10s was possible. In addition, error analyses are made and a method of comparing intensities from angular dispersion to energy dispersive lines is present

ISSN:0049-8246    

DOI:10.1002/xrs.1300110106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractAn improved x‐ray fluorescence method has been developed for the analysis of chrome containing refractory materials (raw materials, in process and final products). It involves the fusion of the powdered samples with a mixture of sodium hexametaphosphate and lithium metaborate in the presence of lanthanum oxide into a glass disc followed by polishing of the disc before exposure to the x‐rays. Three British standards, two South African Standards and one NBS Standard were used for standardizing the method. SiO2, Fe2O3, Al2O3, CaO MgO and Cr2O3were used in the standardization because these compounds constitute the majority of the materials under analysis. Linear regression analysis of the data showed that all the lines were linear, the coefficient of determination being equal or close to 1.00 with a mean error of less than ±3.5%, excepting CaO which had a mean error of ±8.6% because of its low concentration and the larger variance in its standard

ISSN:0049-8246    

DOI:10.1002/xrs.1300110107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe binder is composed of nine parts (by mass) styrene copolymer and one part wax. Both ingredients are marketed under brand names and are available as 10 μm powders, which can be conveniently blended in bulk. Exceptionally robust briquettes containing 10% binder have been made from a great variety of sample types, including metal powders, ion exchange resins, coal, charcoal, graphite, ash, vegetable matter and geological materials. Normally the sample and binder are milled together in a swing mill and milling behaviour is not adversely affected. The briquettes are not affected by vacuum, radiation or age. Erratic milling efficiency of the six‐vessel swing mills used and modifications to overcome the problem are described. For the most satisfactory ejection of a briquette, the cylinder wall of the die should taper slightly outwards near the ejecting end. A pressure of at least 0.04 MPa is recommended to ensure maximum x‐ray fluorescence intensity, but higher pressures improve briquette strength. In the above‐mentioned laboratory 0.23 MPa is normally used. The time the briquette is held under full load is not important. The simplicity of the method makes it possible to mill and press more than 1000 briquettes per day. Binder cost is approximately 3 cents pe

ISSN:0049-8246    

DOI:10.1002/xrs.1300110108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractA method is described for the calibration of Ar Kα counting rates, measured using crystal spectrometers equipped with Ar‐flow proportional counters. Linear extrapolation from overvoltage corrected x‐ray yields of the elements with Kα x‐ray energies lower than those of the ArK absorption edge gives an accurate description of the experimental Ar Kα intensity ratios from counters operated at different values of gas pressure. Results of all‐element film analyses provided by a matrix correction procedure, ZAF, indicate an accuracy better than 5% relative for the determination of Ar concentrations ranging from 0.1

ISSN:0049-8246    

DOI:10.1002/xrs.1300110109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300110110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300110111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY