ISSN:0049-8246    

DOI:10.1002/xrs.1300180102

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

年代:1989

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300180103

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

年代:1989

数据来源: WILEY

摘要:

AbstractA new approach to problems associated with enhancement effects in XRF analysis, and by analogy to analysis by electron microprobe and PIXE, is discussed. The concept of enhancement as ‘relative excess absorption’ is introduced. This concept allows an arrangement of mass balances in which the concentration of any given element may be derived explicitly from a set of relationships equivalent to fundamental expressions, such as the Lachance–Traill and Tertian equations for monochromatically excited XRF and the Claisse–Quintin equations for polychromatic excitation. In this new approach the values of μk′(λiorEi) may be derived, and carry the meaning of apparent mass absorption coefficients for absorption and enhancement effects characteristic of any given pair of elements. Finally, some obvious convergences between XRF, electron microprobe and PIXE analyses are

ISSN:0049-8246    

DOI:10.1002/xrs.1300180104

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

年代:1989

数据来源: WILEY

摘要:

AbstractSEM micrographs showing porous structures and bonding of pores through broken mica flakes are presented. Pores of varying dimensions (10–400 μm) are formed. Interlayer spaces in mica are shown to be the preferential direction for heat and subsequently crack propagation during heat treatment for producing cellular insulating bricks at 900°C. The cracks end up with the formation of large pores in the presence of foaming agent and sodium silic

ISSN:0049-8246    

DOI:10.1002/xrs.1300180105

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

年代:1989

数据来源: WILEY

摘要:

AbstractA Monte Carlo code previously used in modelling x‐ray emission by incident electrons of several tens of kilo‐electronvolts has been extended up to 300 keV, which is typical of the present medium‐energy transmission electron microscopes. With the aid of a further numerical code, both the thickness and composition of thin self‐supporting films can be simultaneously determined. This code exploits the bootstrap statistical method, which provides a realistic error analysis of the final results from the precision of the experimental data. The potential of the two codes is illustrated through a simulated example of a single self‐supporting film. Such calculations can also be applied to two or more overlying films transparent to an elec

ISSN:0049-8246    

DOI:10.1002/xrs.1300180106

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

年代:1989

数据来源: WILEY

摘要:

AbstractSamples in the form of metallic disc are frequently used in the analysis of cast iron by x‐ray emission spectrometry and give good results for common analyses (determination of carbon, sulphur, phosphorus, silicon, manganese, copper, etc.) because of the uniform distribution of the analyte in the sample. However, the results of the analysis of metallic disc samples of cast iron to which cerium had been added were poor, which could be attributed to a non‐uniform distribution of compounds which cerium formed with sulphur and oxygen. A more detailed investigation of cerium distribution in relation to its content in the sample gave evidence of the presumed non‐uniform distribution. Scanning electron microscopy confirmed the presence of unequally distributed aggregates of different size containing cerium, sulphur and oxygen. On the basis of an examination and comparison of published pretreatment procedures, a modified procedure including cerium precipitation with oxalate without transformation into the oxide form is proposed. Using this method, greater reliability of the results was obtained than in the analysis of cast iron samples without pretreatment, i.e. in the disc

ISSN:0049-8246    

DOI:10.1002/xrs.1300180107

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

年代:1989

数据来源: WILEY

摘要:

AbstractEnergy‐dispersive x‐ray fluorescence was used to study the variations in the elemental concentrations of ceramic glazes. The results show the constancy of the concentrations of Rb, Sr, Y, Zr and Nb and also of the Mn/Co ratio determined at different positions in a piece of porcelain. They also show that during the Qing dynasty, it was common practice to use a different glaze for the base of a piece of porcelain, in contrast to the modern practice of using the same glaze for the whole pi

ISSN:0049-8246    

DOI:10.1002/xrs.1300180108

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

年代:1989

数据来源: WILEY

摘要:

AbstractPeak intensities of Fe Kα and scattered W Lα were repeatedly measured on 10‐μg iron‐impregnated and blank pieces of filter‐paper, repeatedly remounted or as mounted, at their 20 angles reset or as set, by the fixed‐time method at various times. Relative standard deviations (RSDs) of the Fe Kα intensity and Fe Kα/W Lα intensity ratio and the detection limit (DL) of iron were compared among these repeated measurements. With a constant total counting time, subdivision of the total time into a large number was preferable for the trace analysis of impregnated thin samples. Slight variations in the sample mounting had a large effect on the RSD and DL, whereas variation in the angle setting had a negligible effect. The use of the scattered W Lα intensity as an internal standard had no advantage in the trace analysis o

ISSN:0049-8246    

DOI:10.1002/xrs.1300180109

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

年代:1989

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300180110

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

年代:1989

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300180111

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

年代:1989

数据来源: WILEY