ISSN:0049-8246    

DOI:10.1002/xrs.1300200202

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe basis of a universal software approach to assist in decisions related to those ecological problems appropriate for investigation by energy‐dispersive x‐ray fluorescence analysis is described. This concept is based on the use of the fundamental physical parameters of the interaction of radiation with materials; it uses modern mathematical methods, can be applied to many different ecological problems and is usable for a wide variety of x‐ray equi

ISSN:0049-8246    

DOI:10.1002/xrs.1300200203

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

年代:1991

数据来源: WILEY

摘要:

AbstractA procedure for automaied microanalysis is adapted from a correction procedure for bulk samples. A particle size correction, based on the projected diameter of the particle, assumed to be spherical, is implemented when the diameter is less than or equal to the electron interaction diameter. A bulk correction is applied in the opposite case. The method is applicable to K‐ and L‐lines for the elements Na to Bi. The method is implemented in a FORTRAN computer program QUANTA written for personal computers. The procedure offers interactive control of several parameters of a single ZAF correction as it is capable of processing the massive amount of data produced by automated analysis of large particle collections. The method uses literature data on a number of fundamental parameters and performs the ZAF corrections by making a compromise between calculation speed and accuracy using first‐order corrections for backscattering, absorption and secondary fluorescence effects. It was tested on a set of alloy standards, mineral standards and mineral particle stan

ISSN:0049-8246    

DOI:10.1002/xrs.1300200204

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

年代:1991

数据来源: WILEY

摘要:

AbstractA novel method for estimation of the effective nuclear charge (Zeff) on the central metal atom in cobalt complexes from the x‐ray K‐absorption discontinuity is proposed. Its potential is discussed on the basis of statistical analysis of the data obtained from the results for 25 cobalt complexes which indicated fairly good agreement between the observed and the estimated values ofZefffor the cobalt a

ISSN:0049-8246    

DOI:10.1002/xrs.1300200205

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

年代:1991

数据来源: WILEY

摘要:

AbstractA rapid method for the simultaneous determination of trace elements in milk powder by energy‐dispersive x‐ray fluorescence has been developed. The measurement system consists of an Si(Li) detector, an x‐ray tube coupled with zirconium as a secondary target excited source and a personal computer. Milk powder was analysed as pressed pellets and irradiated for 1000 s. Concentrations were determined by a fundamental parameters method. The detection limits are close to 1 ppm for most of the trace elements. The accuracy of the method was ascertained by analysing standard reference materials from the International Atomic Energy Agency. Good agreement was found between the certified and experimental values. Potential areas of applicability of the method are indi

ISSN:0049-8246    

DOI:10.1002/xrs.1300200206

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

年代:1991

数据来源: WILEY

摘要:

AbstractAn empirical study of the precision of measurement by energy‐dispersive (EDS) and wavelength‐dispersive (WDS) techniques is described. Combined EDS–WDS quantitative analysis provides efficient instrument operation, optimum precision in major element analysis and the best limits of detection in trace element analysis. A software package for a combination EDS–WDS electron microprobe is de

ISSN:0049-8246    

DOI:10.1002/xrs.1300200207

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

年代:1991

数据来源: WILEY

摘要:

AbstractA semiempirical non‐linear model for the on‐stream x‐ray fluorescence analysis of slurries was developed, utilizing the intensities of fluorescent and scattered radiation. It is assumed that the slurry consists of liquid and solid parts. All components of the solids except the elements to be measured are considered to be a filling substance with an approximately constant absorption coefficient. The model permits the calculation of the elemental weight fractions in the solids without the need for the determination of the solid content in the slurry. The accuracy and reproducibility of the method are compared with those of existing multiple regression models. A non‐linear expression for the determination of the solid content in the slurry using the intensity of scattered x‐radiation is proposed and compared with some polynomial regressi

ISSN:0049-8246    

DOI:10.1002/xrs.1300200208

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

年代:1991

数据来源: WILEY

摘要:

AbstractA study of oxygen Kα peak shifts using an electron probe microanalyzer with a W–Si multilayer pseudo‐crystal (2d= 59.8 Å) shows a significant peak shift (0.024–0.043 Å) between simple oxide minerals (e.g. quartz) and minerals containing complex oxygen radicals (e.g. SO 42−, CO 32−and PO 43−). The peak shift of the complex oxygen radicals toward the lower wavelength (or higher energy) side of the simple oxides may indicate a relatively stronger bonding energy inside these radicals than that of the simple cation—oxygen bond. In the direct determination of oxygen, a peak count reduction could occur as a result of this peak shift effect if unsuitable oxy

ISSN:0049-8246    

DOI:10.1002/xrs.1300200209

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

年代:1991

数据来源: WILEY

摘要:

AbstractM‐shell x‐ray production/fluorescence (M XRF) cross‐sections for five elements with 81 ≤Z≤ 92 were measured at 5.96‐keV incident photon energy using thin targets. From the measured M XRF cross‐sections the average M‐shell fluorescence yields were derived. Experimental results for XRF cross‐sections and fluorescence yields were compared with theory. The experimental results were found to be higher than the theoretical values by 10–17%. Further experimental investigations on M XRF cross‐sections for more elements at different excitation energies are required in order to check the validity of the theoretical parameters used to calculate the

ISSN:0049-8246    

DOI:10.1002/xrs.1300200210

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe influence of the effect of sample loading heterogeneity on the accuracy of the emission–transmission technique applied in the x‐ray fluorescence analysis of specimens of intermediate thickness was studied. Various types of sample loading heterogeneities, including incompletely loaded samples, were considered. General expressions describing the accuracy of the emission–transmission method within a wide range of sample thicknesses and characteristic x‐ray energies were derived. Experiments for the verification of the theoretical predictions were also carried out for some selected test samples of known sample loading inhomo

ISSN:0049-8246    

DOI:10.1002/xrs.1300200211

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

年代:1991

数据来源: WILEY