Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: K. Ôhashi x
  • All content x
Clear All Modify Search

Получен критерий вып олнения центральной предельной теоремы для рядов Уолша с лакунами обще го вида. Как следствие получено улучшение результат ов БЕРКЕША [1]. В теореме 3 да ны условия для сходим ости к квази-гауссовым расп ределениям.

Restricted access

Abstract  

The synergistic effect on the extraction of thorium(IV) was found by the combination of 2-thenoyltrifluoroacetone (Htta) and 1,10-phenanthroline (phen) or 4,7-diphenyl-1,10-phenanthroline (dpp) as a neutral bidentate ligand. Especially in the presence of dpp (1·10–3M) in benzene, the distribution ratio of thorium(IV) increased by a factor of about 300. Such synergistic enhancement of the extraction was ascribed to the formation of the adduct complex of Th(tta)4(phen) and Th(tta)4(dpp) in the organic phase. The extraction constant and the adduct formation constant were determined and discussed.

Restricted access

Abstract  

Substoichiometric isotope dilution analysis for the determination of trace iron has been studied by using synergistic extraction of iron(III) with a substoichiometric amount of 4-isopropyltropolone (Hipt) in the presence of an excess of 3,5-dichlorophenol (DCP) in heptane. Optimum conditions for the substoichiometric extraction of iron(III) in g to sub-g levels were examined and the high selectivity for iron(III) toward various metal ions encountered in the analysis of biological materials was confirmed. The present method was applied to a biological reference material (NIES, CRM No.9, sargasso) without any pre-separation and was successfully evaluated. Furthermore, substoichiometric stable isotope dilution mass spectrometry using the present extraction method was also used with the above sample. Applicability and practicability was compared for both substoichiometric methods.

Restricted access

Abstract  

A novel analytical method, the substoichiometric isotope dilution mass spectrometry (SIDMS) has been proposed. This method consists of the substoichiometric separation of the element in question and the subsequent intensity measurement of a stable isotope of the element with a mass spectrometer. In SIDMS, the correction of the mass discrimination of isotope measurement is not necessary and the use of expensive enriched stable isotopes may be avoided. The validity and the usefulness of SIDMS are demonstrated by the substoichiometric extraction of iron(III) with 4-isopropyltropolone and 3,5-dichlorophenol following microwave-induced plasma mass spectrometry.

Restricted access

Abstract  

A simple method to determine -ray attenuation coefficients using Ba-133 -rays has been developed and applied to self-absorption correction in routine -ray spectrometry for environmental samples composed of unknown matrix elements. Experimental values of the mass attenuation coefficient obtained by the method agree well with calculated values for samples of known elemental composition which was determined by means of chemical analysis.

Restricted access