ISSN:0049-8246    

DOI:10.1002/xrs.1300230502

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

年代:1994

数据来源: WILEY

摘要:

AbstractAnalytical convolution methods used to explain the interaction of a fine electron beam with a thin segregated layer in a typical electron microscope specimen are described. Expressions are derived which quantify the shape of the measured concentration profile determined in the microscope by scanning the beam across the segregated layer. The expression contains parameters concerned with the beam profile and the thickness of the segregated layer. The method is applied to grain boundary segregation studies of neutron‐irradiated ferritic‐martensitic ste

ISSN:0049-8246    

DOI:10.1002/xrs.1300230503

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

年代:1994

数据来源: WILEY

摘要:

AbstractSubmicrometer phase quantitative analysis is always a challenging problem for electron beam microanalysis because the phase is smaller than the electron beam and the specimen interaction volume. In order to obtain more accurate composition information, other analytical techniques need to be used to clarify the elements present and characterize the valence state of major elements in that submicrometer phase In this study, the electron probe microanalyzer (EPMA) was used to determine the contamination phase in the tungsten carbide‐cobalt ceramic system. The average size of the contamination phase was approximately 0.5 μm in diameter. The chemical composition of the contamination phase was elucidated by combining results from x‐ray mapping, valence state determination and EPMA quantitative analysis data. The effect of the contamination phase in the tungsten carbide‐cobalt ceramic system is also dis

ISSN:0049-8246    

DOI:10.1002/xrs.1300230504

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

年代:1994

数据来源: WILEY

摘要:

AbstractCross‐sections for the production of Ll, Lα, Lβ and Lγ x‐rays in 22 elements (57 ≤Z≤ 92) by photons of 13 different energies in the range 8–50 ke V are reported. The experimental values of the cross‐sections were determined by measuring the absolute yield of L subshell x‐rays emitted from a target of a given element and thickness when it was bombarded with a known flux of photons of given energy. The theoretical values of the cross‐sections were calculated from the theoretical/semi‐empirical values of subshell photoionization cross‐sections, fluorescence yields, Coster‐Kronig transition probabilities, intra‐shell transition probabilities and radiative decay rates. The present and previous measured and calculated values of the cross‐sections are tabulated to bring out the existing status of L x

ISSN:0049-8246    

DOI:10.1002/xrs.1300230505

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

年代:1994

数据来源: WILEY

摘要:

AbstractA wavelength‐dispersive x‐ray fluorescence method is described for the determination of total chlorine in fresh and seasoned photographic developer solutions. The method uses a cadmium internal standard to correct for slight changes in the solution matrix and covers a concentration range of 15–500 mg l‒1chlorine. Precision studies using the method resulted in a relative standard deviation (RSD) of 0.41% (1s) at the 200 mg l‒1chlorine level and a RSD of 1.13% (1s) at the 50 mg l‒1level. The limit of detection for chlorine was found to be 5 mg l‒1and the limit of quantification was calculated

ISSN:0049-8246    

DOI:10.1002/xrs.1300230506

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe contribution of photo‐ and Auger electrons generated in analyte material to the x‐ray fluorescence of elements with atomic numbers fromZ= 5 (boron) to 9 (fluorine) was evaluated. The calculations were performed for different x‐ray tube anodes, window thicknesses and working regimes. This contribution to x‐ray fluorescence excitation increases rapidly with decreasing atomic number of the measured element and depends greatly on the sample composition and experimental conditions. In some cases the contribution may exceed 90%. This high value results from the absorption in the window and in the x‐ray anode tube material of the long‐wavelength component of primary radiation which is most effective in photoionization of element atoms. It follows from the calculations that at shorter wavelengths, e.g. for Na and Cu, the contribution of photo‐ and Auger electrons to the excitation of their fluorescence seems to be much less significant than that obtained

ISSN:0049-8246    

DOI:10.1002/xrs.1300230507

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe distribution of the publications on x‐ray fluorescence analysis among different journals is discussed on the basis of frequency of citation in major review articles. Differentiation among major sub‐fields such as particle induced X‐ray emission, total‐reflection x‐ray fluorescence and synchrotron radiation induced X‐ray fluorescence is studied. A comparison with the results from a computer search in theScience Citation Indexand INSPEC databases is presented. Important sources of new information in x‐ray fluorescence analysis are identified

ISSN:0049-8246    

DOI:10.1002/xrs.1300230508

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

年代:1994

数据来源: WILEY

摘要:

AbstractK and L emission spectra of the carbide, boride, nitride, silicide and silicocarbide of molybdenum were studied using x‐ray spectrometry method. It was observed that satellite lines influence the K and L spectra in these molybdenum compounds. From the chemical shift of these lines, the nature of the bonding is found to be covalent in these compounds. Further, hybridization of both p‐d and s‐p orbitals plays a major role in shifting these lines and high asymmetry indices. In MoSi2and MoSi3C a quasi‐gap is found to be present. The abnormally high value of theI Kα 2/I Kα 1ratio was explained on the basis of multi‐hole configuration, shake‐off and Coster‐Kronig processes taking

ISSN:0049-8246    

DOI:10.1002/xrs.1300230509

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

年代:1994

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300230510

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

年代:1994

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300230511

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

年代:1994

数据来源: WILEY