摘要:

An automated multidetector system for instrumental thermal neutron activation of geological and environmental materials was used for the measurement of up to 34 elements in six National Bureau of Standards Standard Reference Material coal samples. Good agreement was achieved with NBS certified and literature consensus values.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00809.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

This paper extends Nair's exact Table of 952 and 99% confidence intervals for the median to data sets containing up to 300 observations.It provides for an approximate relationship especially useful when the number of observations is large, and allows to calculate quickly confidence intervals affected only seldom and occasionally by tolerable error.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00810.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

For evaluating the analytical data on reference samples, the following approach is proposed: 1. Analytical methods used are critically reviewed. 2. Outliers are eliminated. 3. Normality of the results is tested. 4. If normality of the results can be accepted, arithmetic mean, its confidence interval and coefficient of the precision are computed. 5. If the results are not normally distributed, median and its statistical characteristics are given. 6. For sets of data with anomalous skewness, logarithmic and lambda transformations are useful approaches.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00811.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The stability of geochemical reference materials is subject to breakdown due to mineralic component or particle size fraction segregation or to ambient oxidation. A statistical design is presented to the analyst for detecting such a breakdown as soon as possible to avoid the resultant degradation in his output. The application of this design to a base metal certified reference material, MP‐1a, is illustrate

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00812.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Some trace‐element contents of U.S. Geological Survey (USGS) samples, biotite Btt‐1 and hornblende Hbl‐1, were determined by both computerized semi‐quantitative spectrographic analysis and instrumental neutron activation analysis. An equal number of portions of the Centre de Recherches Pétrographiques et Géochimiques (CRPG) samples, biotite Mica‐Fe and phlogopite Mica‐Mg, were randomized with portions of the USGS samples and analyzed simultaneously to allow direct comparisons of trace elements in the biotites. Mica‐Fe has concentrations of Cs, Hf, Ta and Zn that are greater by factors of 3 or more than those in Btt‐ 1. Although the Co contents of the two biotites are nearly equal, the amounts of Cr, Sc, La and the rare earth elements are significantly greater in Btt‐1. Mica‐Mg contains larger amounts of Cs and Rb than does Hbl‐1, whereas the Cr content of Hbl‐1 is 15 times that of Mica‐Mg. Btt‐1 and Hbl‐1 may be useful as comparison samples for the analysis of biotites and hornblendes

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00813.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00814.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1986.tb00815.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY