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  • Author or Editor: Y. Minai x
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Abstract  

Seven REEs in the deep sea sediments from various regions /19 sites/ of the Pacific Ocean and the Japan Sea were determined with INAA. Regional variations of La/Yb ratio and Ce anomaly may reflect the relative contribution of the source materials in the formation of the deep sea sediments.

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Abstract  

Tris(1,10-phenanthroline) iron(II) ([Fe(phen)3]2+) ion synthesized in the supercage of zeolite Y has been characterized by Mössbauer, UV-VIS reflectance, and X-ray diffraction methods. The complex in the supercage may be significantly distorted by interaction between the complex and the supercage wall. Pyrolysis mechanism under air of the complex in the supercage was studied on the basis of Mössbauer spectra.

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Abstract  

Line-broadening due to paramagnetic relaxation was observed in Mössbauer spectra of Eu2+ in glassy frozen solutions; such broadening may be used as an indicator of the state of dispersion of europium. It was demonstrated by the Mössbauer technique that Eu2+ was oxidized to Eu3+ by photoirradiation at >300 nm and that this oxidation reaction was induced by photoexcitation of the 320-nm band of Eu2+.

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Abstract  

By means of INAA, REEs in the dredged rocks from a seamount /KH73-4-2/ in the East Mariana Basin were determined. Based on the REE patterns, the rocks are classified into two groups despite of alteration: highly altered palagonite of oceanic-island tholeiitic nature, and relatively fresh basaltic-andesitic rocks of alkaline rock nature.

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Abstract  

Binding constants of Eu(III)- and Am(III)-complexes with soil-derived humic acid were determined by solvent extraction at various pH and ionic strength. Based on the dependence of binding constants on pH and ionic strength, stabilities of the humate complexes in land water and seawater were estimated. Speciation calculation based on the binding constants indicated that Am(III) could combine with humic substances in natural water system.

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Abstract  

Luminescence lifetime of Eu(III) in polyacrylate and polymaleate complexes has been measured to evaluate the number of water molecules bound to the ion. The number of residual water molecules hydrated to Eu(III) in the polyacrylate and polymaleate complexes ranged from 3.5 to 4.5 when the supporting electrolyte concentration was 0.01. The residual hydration number decreased with the addition of supporting electrolyte. These results indicate that Eu(III) is surrounded by polymolecular ligands in these complexes.

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Abstract  

The effect of ZnCl2 on the uptake of Be, Na, Mn, Co, Zn, Se, Rb, Sr, Rh, Cs and lanthanoids (Ce, Pm, Gd and Lu) by carrot (Daucas carota cv. U.S. harumakigosun) was investigated. Uptake was measured using a multitracer technique which enables to acquire information about various elements under identical conditions. The amount of uptake of Rb, Cs, Sr, Mn and Co, into roots decreased with increasing concentration of ZnCl2. On the other hand, little effect was observed for the uptake of Be, Se, Rh and lanthanoids. These results suggest that Rb, Cs, Sr, Mn and Co competed antagonistically with Zn for the binding sites of carriers in the roots, while there was no influence on the uptake of the other elements. Uptake of Se was not influenced by Cl added as ZnCl2. It is concluded, therefore, that carrot can distinguish Se from Cl based on the physicochemical differences between these two anion species.

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Abstract  

The state of dispersion and photochemical behaviour of tris/-diketonato/ iron/III/ complexes isolated in low temperature matrices were characterized by means of57Fe Mössbauer spectroscopy. Tris/acetylacetonato/iron/III/ iron/III/ molecules isolated in a nitrogen matrix were aggregated by photoexcitation. Photoreduction of tris/hexafluoroacetylacetonato/-iron/III/ in solid ethanol was also monitored by the Mössbauer technique.

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Abstract  

The UV photolysis of pentacarbonyliron isolated in low temperature nitrogen matrix was studied by the Mössbauer Technique. Besides stable compounds /Fe2/CO/9 and Fe3/CO/12/ unstable species such as Fe/Co/4 and Fe2/CO/8 were produced by UV irradiation. Furthermore, the unstable species were found to react with nitrogen matrix, leading to the formation of Fe/CO/4N2. Mössbauer parameters of the products were obtained.

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Abstract  

Lanthanides in altered oceanic tholeiite were determined by means of instrumental neutron activation analysis. Potassium content was employed as a measure of degree of alteration. Lanthanide concentrations in moderately altered parts of tholeiite (K2O content below 1%) were identical with those in'unaltered parts while light lanthanide concentrations in more altered parts (K2O content above 1%) increased with degree of alteration.

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