Search Results

You are looking at 1 - 10 of 23 items for

  • Author or Editor: Y. Minai x
  • Refine by Access: All Content x
Clear All Modify Search

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.

Restricted access

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.

Restricted access

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+.

Restricted access

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.

Restricted access

Abstract  

Distribution of trace amount of Eu(III), or Am(III), in the aqueous/solid system containing humic acid and kaolinite, or montmorillonite, was studied by batch experiments. Humic acid was also adsorbed on the clay minerals and its adsorption isotherm can be regarded as a Langmuir type. It is shown that Eu(III), or Am(III), exists as humate complex either in the aqueous or on solid phase in the system including kaolinite, or montmorillonite. These results suggest that the organic-inorganic complex like clay minerals coated with humic substances is important as metal reservoir in the environment.

Restricted access

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.

Restricted access

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.

Restricted access

Abstract  

Cesium content in eleven positions of a continental basalt with a columnar joint was determined by means of neutron activation analysis. Concentration of cesium is about four times higher at the altered portions of the fracture than at the unaltered. Water and Fe3+ content determined by gravimetry, Mössbauer spectroscopy, and inductively coupled plasma optical emission spectroscopy were also correlated with cesium concentration, suggesting accumulation of cesium with ferric components. Such processes may be important for estimating the behavior of radiocesium in the environment.

Restricted access

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.

Restricted access

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.

Restricted access