ISSN:0049-8246    

DOI:10.1002/xrs.1300070102

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

年代:1978

数据来源: WILEY

摘要:

AbstractAn X‐ray method has been developed for the routine determination of niobium, tantalum and residual elements inferrniobium. The sample is pre‐ooxidized and fuded in a misture of lanthanum oxide and lithium tetraborate. Calibration is by synthetic standards; molybdenum is added as internal standard for niobium, and corrections are applied for interferences on tanta

ISSN:0049-8246    

DOI:10.1002/xrs.1300070103

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

年代:1978

数据来源: WILEY

摘要:

AbstractA simple approach of the study of phase equilibria in niobium‐germanium alloys involves passing a floating molten zone along the alloy, cutting the resolidified rod into several, and analysing these sections by X‐ray fluoresce spectrometry and X‐ray diffraction. The relative net X‐ray fluorescent intensities were corrected for negative absorption effects, using a semi‐empirical procedure. The ‘effective wavelengh’ for exicitation of niobium and of germanium were deduced from experimental alpha

ISSN:0049-8246    

DOI:10.1002/xrs.1300070104

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe Mn Kβ1,3, Kβ′ X‐ray emission peak profile varies in a characteristic way with the valency of manganese, Proviede that the ligand‐atom environment remains contant. Kβ′ becomes mopre prominent as the oxidation state is reduced. XRF nanalysis of geological sample can, therefore, be easily extended to include a determination of the predominant valence state of any mangane

ISSN:0049-8246    

DOI:10.1002/xrs.1300070105

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe positions and shapes of L2 X‐ray absorption edges of Gd, Dy, Ho and Er have been studied in metals and in oxides and chlorides, using a forty centimetre benbt mica crystal spectrograph. It has been found that the L2 edge shifts towards the high energy side in the compounds and that the chemical shift ΔEdepends on the degree of covalency involved. The white line structure at the edge has been analysed in terms of transitions of L2 shell electron to opticalnd(n≥5) st

ISSN:0049-8246    

DOI:10.1002/xrs.1300070106

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

年代:1978

数据来源: WILEY

摘要:

AbstractA modified covell method for direct peak analysis has been applied to energy‐dispersiv X‐ray flourescence spectra. The method is background independent and is well‐suited to computerized data reduction. It provides acceptable precision, minimizes errors from instrumental gain shift, and permits peak overlap correction. Peak overlap errors exhibit both positive and negative nodes as a function of peak separation distance, and are corrected using concentration ratios determined from thin, single‐element standards. Peak precisions and overlaps are evaluated as a function of window width to aid in width selection. Least‐square polynomial smoothing prior to peak analysis significantly improves peak area precisions without significantly affecting their a

ISSN:0049-8246    

DOI:10.1002/xrs.1300070107

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe Kα1,2, Kβ1,3, Kβ5, and Kβ″ emission spectra of vanadium in the element and several V (III), V(IV), and V(V) compounds have been measured with a two‐crystal X‐ray spectrometer. The Kα1and Kβ1,3peaks shift slightly to lower energies with increasing lthe oxidation state of vanadium atom and the Kβ5peak shifts to higher with it. An approximately linear relationship between Kα1width and Kα1/Kα2intensity ratio can be used for lindentification of vanadium

ISSN:0049-8246    

DOI:10.1002/xrs.1300070108

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

年代:1978

数据来源: WILEY

摘要:

AbstractFrom an extensive series of measurements of ϕ(ρz) curves, at electron energies between 6 and 15 KeV, an empirical formula;ϕ(R)=DKn(KR)n−1exp(−(KR)n) where R=ρz+ρzo, was developed to accurately describe the shape and magnitude of the measured curves. On the basis of this equation a quantitative correction for absorprion and atomic mumber effects has been derived for low electron energies. A comparision of quantitative analysis using the above equation wit other absorption and atomic number corrections shows better agreement between calculated and known concenequation to a correction for fluorescence due to characteristic lines is

ISSN:0049-8246    

DOI:10.1002/xrs.1300070109

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

年代:1978

数据来源: WILEY

摘要:

AbstractAnlysis of uranium (VI) by X‐ray fluorescence methods, using selective solvent extraction with tri‐n‐ octulphosphin‐oxide (TOPO) has been studied. The analysis of uranium in copper leach solutions has proved successful and results indicate that this method can be used for uranium levels doen to 3ppm. The coefficient of variation (CV) at a value of 30 ppm was calculated to be CV

ISSN:0049-8246    

DOI:10.1002/xrs.1300070110

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe Thallium Acid Phthalate (TIAP) analysing crystal is compared with KAP, RBAP and pentaerythritol (PE) crystal for the determination of light elements. Peak and background intensities are compared for various crystal‐collimator combinations. It is shown that TIAP is a very useful crystal to cover the range of elements F to S

ISSN:0049-8246    

DOI:10.1002/xrs.1300070111

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

年代:1978

数据来源: WILEY