ISSN:0049-8246    

DOI:10.1002/xrs.1300170202

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

年代:1988

数据来源: WILEY

摘要:

AbstractAn absolute method for the determination of the thickness of a nickel film on iron has been developed. The mass absorption coefficient of nickel for the effective wavelength has been determined empirically and mathematically. The found values were in agreement. To perform this method only one intensity measurement of the fluorescent substrate emission is required (Fe Kα). The method was tested using iron sheets with different thicknesses of nickel obtained by chemical deposition. Thicknesses between 6 and 25 μm produced relative differences from gravimetric values of 1.8‐1

ISSN:0049-8246    

DOI:10.1002/xrs.1300170203

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

年代:1988

数据来源: WILEY

摘要:

AbstractA method is derived, using information theory and the maximum entropy principle, for treating deconvolution problems. The approach is particularly suitable for the determination of instrumental effects in spectral lines. The technique is illustrated by recourse to numerical examples. A comparison is made with alternative methods. Although realistic situations are restricted to the correction of x‐ray diffraction profiles (instrumental width), the formalism applies for any spectral techniqu

ISSN:0049-8246    

DOI:10.1002/xrs.1300170204

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

年代:1988

数据来源: WILEY

摘要:

AbstractX‐ray fluorescence cross‐section for Kα x‐ray lines were measured for the light elements Na, Mg, Al, Si, S, Cl and K relative to Ca at a photon excitation energy of 5.97 keV (Mn K x‐ray). A windowless retractable Kevex Si(Li) detector system having an energy resolution of 146 eV at 6.4 keV was used for the detection of the characteristic K x‐rays. The measurements were performed in a vacuum chamber maintained at a pressure ofca10−7Torr using a55Fe radioactive excitation source and targets of ultra‐pure elements/compounds of the above‐mentioned elements. Cross‐sections were also calculated using photoelectric cross‐sections, fluorescence yields and the fractional x‐ray emission rates. Measured and calculated x‐ray fluorescence cross‐sections agree

ISSN:0049-8246    

DOI:10.1002/xrs.1300170205

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

年代:1988

数据来源: WILEY

摘要:

AbstractOptimization of EDXRD measurements using the diamond anvil high‐pressure cell varies with the particular experimental objectives. In the case ofP‐V‐Tequation of state studies, the controllable factors are adjusted to optimize the precision and accuracy of the interplanar spacing measurements. The identification of new phases requires the optimization of lattice parameter determinations and the minimization of the effects of thickness on the relative intensities, whereas for reaction rate studies the various factors are adjusted to maximize the absolute intensities of the peaks of interest. In each of these cases there are trade‐offs in the effects of the individual factors that must be made in order to optimize the measurements. Of these factors, the sample absorption is often the most important. For example, profound changes in the relative intensities of diffraction peaks during normal compression studies are caused by the coupled effects of normal sample absorption as the sample thins and the energy dependence of the absorption coefficient. Such changes in relative intensities could be incorrectly attributed to uniaxial stress, residual stress, order‐disorder phenomena or element partitioning. Coupled absorption effects in the presence of a powdered, internal standard also have an important bearing on optimizing the relative proportions of admixed standard a

ISSN:0049-8246    

DOI:10.1002/xrs.1300170206

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

年代:1988

数据来源: WILEY

摘要:

AbstractFive readily available fundamental parameters x‐ray spectrometry programs were compared for their performance in a more or less routine laboratory environment. The programs were used to determine a variety of elements in cement, geological samples, low‐alloy steels, nickel alloys and plant material. All data were acquired using energy‐dispersive x‐ray spectrometry. Criteria used in the comparison include accuracy, versatility and ease of use. Performance is given in statistical su

ISSN:0049-8246    

DOI:10.1002/xrs.1300170207

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

年代:1988

数据来源: WILEY

摘要:

AbstractAn XRF method was developed for the determination of Mg and Si in aluminium alloys in the range from 0.1 to 0.7 wt%, using a Si(Li) semiconductor detector, a3H/Ti ring‐shaped radioactive source and a microcomputer. The Mg Kα and Al Kα lines were separated both with the help of library spectra (deconvolution) and with an Se absorption edge filter. The optimum values of the geometrical parameters were determined. Two3H/Ti sources, covered and not covered with Cr, were tested. The standard deviations of concentrations determined by different methods was compa

ISSN:0049-8246    

DOI:10.1002/xrs.1300170208

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

年代:1988

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300170209

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

年代:1988

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300170201

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

年代:1988

数据来源: WILEY