Hafnium-Zirconium and Tantalum-Columbium Systems. Quantitative Analysis by X-Ray Fluorescence

Birks, L. S.; Brooks, E. J.

doi:10.1021/ac60044a013

Cited by 58 publications

(12 citation statements)

References 7 publications

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“…The labels for the different catalysts were chosen on the basis of their elemental compositions, which were determined by proton‐induced X‐ray emission (PIXE) analysis. In addition to cerium, zirconium, and oxygen, only a small hafnium impurity (less than 0.3 mol %) was detected 36. All of the mixed oxides had surface areas that were higher than that of pure ceria but lower than that of pure zirconia 34.…”

Section: Resultsmentioning

confidence: 94%

Improved variational analyses using a nonlinear humidity control variable

Ingleby

Lorenc

Ngan

et al. 2012

Quart J Royal Meteoro Soc

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A new humidity analysis variable has been successfully introduced into the Met Office's variational data assimilation system. The new variable uses a transformation consisting of a nonlinear normalization and a link with temperature increments that is a function of background (forecast) humidity. The normalization (which is the more important aspect) makes the new variable's errors more symmetrical and thus better represented by the variational cost function. As in the previous operational system, water vapour and cloud are combined into a single total water variable for the analysis step. The transform is now operational in both global and limited-area systems. The forecast improvements -to the mass as well as the humidity fields -are largest in the Southern Hemisphere and there is a better fit of both background and analysis to humidity-sensitive satellite channels. The results suggest that the transformation is particularly beneficial for the use of satellite data. The transform reduces the problem of negative humidities in the analysis which were more prevalent over the ocean.

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Section: Resultsmentioning

confidence: 94%

Improved variational analyses using a nonlinear humidity control variable

Ingleby

Lorenc

Ngan

et al. 2012

Quart J Royal Meteoro Soc

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show abstract

“…Besides cerium, zirconium, and oxygen, only a small amount of hafnium was detected (less than 0.3 mol% in all samples). Hafnium is a common impurity in zirconium precursors [37].…”

Section: Composition Surface Area and Porosity Of The Catalystsmentioning

confidence: 99%

Kinetics of hydrogen activation on ceria–zirconia

Schimming

Foo

LaMont

et al. 2015

Journal of Catalysis

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“…Moreover, pure binary mixtures are required in order to obtain reliable results. These disadvantages do not affect optical emission and x-ray fluoresence spectrometric techniques and procedures covering the range from 0.003% hafnium in zirconium to 0.5% zirconium in hafnium have been described (1,5,6,10,12,13). None of the work published thus far has considered the determination of zirconium below 0.5% in purified hafnium.…”

Section: Literature Citedmentioning

confidence: 99%

“…The background readings used for correction purposes were obtained by averaging the readings on both sides of each line. Preformed graphite electrodes as shown in Figure 3, loaded with mixture of 5 mg. of oxide and 5 mg. of powdered graphite Flat-end graphite rod, Vs inch in diameter, 1 With the zirconium 3391.975 A. line, the background could be read on only one side of the line. The lower electrode employed for direct current carbon arc excitation (Figure 3) was purchased as a modified form of United Carbon Products Co., Inc., Model 101L preformed graphite electrode.…”

Section: Preparation Of Standards and Exposure Conditionsmentioning

confidence: 99%