ISSN:0049-8246    

DOI:10.1002/xrs.1300090102

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe Philips PW 1450/00 or /10 automatic hardware‐programmed X‐ray spectrometer, when used in conjunction with the PW 1466 60 position sample loader, permits measurement of both standard and unknown using the same channel only when the ratio mode is selected. Further, a standard must be measured for every unknown. An electronic modification is described which overcomes both of these restricti

ISSN:0049-8246    

DOI:10.1002/xrs.1300090103

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe problem of estimating the chemical composition of small particles of a phase in a matrix of another occurs in a number of fields. The introduction of electron beam microanalytical techniques has made it possible to analyse a volume of 10μm3. In spite of this advancement the chemical composition of the particles themselves is difficult to determine. This difficulty arises from uncertainty as to the full containment of the analysed volume by the particle being analysed. In this paper a statistical approach to establish the chemical composition of the particles themselves has been proposed. This approach is particularly useful when the particles and the matrix have a common element. Two examples are given, one with components of known compositions and another with a component of an unknown composition

ISSN:0049-8246    

DOI:10.1002/xrs.1300090104

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

年代:1980

数据来源: WILEY

摘要:

AbstractCarefully polished samples of five austenitic stainless steels have been examined by reflected light microscopy and analysed, using a Link Systems model 290 KX energy‐dispersive spectrometer attached to a Cambridge Instrument Company Geoscan microprobe. At least ten different spots within apparently homogeneous areas of each sample were analysed. While the means of these analyses agree well with the published values, three of the samples have an inhomogeneous distribution of their major elements. Precipitates within the samples are mainly MnCr2O4and MnS, both with much substitution of the Mn by other elements. Other precipitates are rich in P or Nb. While such blocks are probably sufficiently homogeneous for use as bulk standards, great care should be exercised if they are to be used as microprobe standards. A small excess of silicon was found in most analyses. This is believed to be due to fluorescent excitation of silicon in the detector. Analyses of pure metals suggest that a correction of 0.12 wt % silicon should be applie

ISSN:0049-8246    

DOI:10.1002/xrs.1300090105

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe theoretical relationships between fluorescence intensity and concentration have been used for the calculation of correction constants of the Lachance‐‐Traill and Rasberry‐‐Heinrich equation for systems of solutions. The constants have also been calculated by means of the multivariate least‐‐squares method. Those two alternatives have been tested on systems of Cu‐‐Fe‐‐Zn and Cu‐‐Fe‐‐Zn‐‐Pb in 3.5% aqueous nitric acid and compared with the simple two‐variable linear relationship between fluorescence intensity and concentration. The multivariate least‐‐squares alternative gives for the Lachance‐‐Traill method very accurate results (average relative deviation does not exceed 0.18%). In a theoretical discussion, the relationship between optimum sample concentration and solvent correction (enhancement) constant is shown. The optimum conditions for

ISSN:0049-8246    

DOI:10.1002/xrs.1300090106

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

年代:1980

数据来源: WILEY

摘要:

AbstractA method is presented for determining the relative amounts of Nb and Ge in thin films of approximately 1 μm thickness which have been deposited onto polycrystalline substrates. Quantitative X‐ray fluorescence is employed using an energy‐dispersive solid state detector and multichannel analyzer system. The principal problem encountered is one of calibrating the observed Ge/Nb intensity ratios in terms of atomic composition. We have used solution standards for comparison with the spectrum of selected dissolved films. The absolute compositions in the region of 25 atomic percent Ge are believed accurate to ±1 atomic percent abs

ISSN:0049-8246    

DOI:10.1002/xrs.1300090107

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

年代:1980

数据来源: WILEY

摘要:

AbstractA non‐linear rise in intensity of copper Kα1and Kα2X‐ray lines has been observed from certain areas of the polycrystalline copper target of a microfocus tube operated at tube currents between 0.1 and 0.5 mA and a tube potential of 13 kV. Under the same conditions the intensity rise of the bremsstrahlung is found to be linear. A functional relationship between total count and tube current has been obt

ISSN:0049-8246    

DOI:10.1002/xrs.1300090108

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

年代:1980

数据来源: WILEY

摘要:

AbstractA non‐destructive method for the determination of platinum in reforming catalysts and doped Venezuelan laterites employing a radionuclide, 8mCi of109Cd, and a PDP‐11/05 processor is presented. The total variation for 100s of fluorescent time is about 3% for a 10% Pt‐reforming catalyst. The total variation can be reduced to less than 1% by increasing the fluorescent time so that about 80 000 counts or greater are accumulated. The platinum was determined using the Lα and Lβ lines of platinum, as well as their sum. The different types of variation for each of these measuring parameters is given. Finally, both the calculated and measured values for the prepared calibration standards and the doped Venezuelan laterites were in excellent ag

ISSN:0049-8246    

DOI:10.1002/xrs.1300090109

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

年代:1980

数据来源: WILEY

摘要:

AbstractA set of most probable Kβ/Kα values estimated on the basis of all available experimental data is presente

ISSN:0049-8246    

DOI:10.1002/xrs.1300090110

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

年代:1980

数据来源: WILEY

摘要:

AbstractA new system for on‐line X‐ray topography is described, in which relative motions of separate assemblies are completely eliminated. The main elements of the system are a low‐power raster‐type X‐ray source with a transmission target and a multi‐capillary collimator. It takes about 2.5–3 min to produce a topograph of silicon single‐crystal (20 × 20 × 0.3mm) when the radiation source

ISSN:0049-8246    

DOI:10.1002/xrs.1300090111

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

年代:1980

数据来源: WILEY