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  • Author or Editor: S. Watanabe x
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Abstract  

The solvent extraction behavior of [TcCl6]2− in the HCl-TBP system was studied together with that of its aqua complexes. It was deduced from the dependence of the distribution coefficient of [TcCl6]2− both on the HCl and TBP concentrations that a possible form extracted into TBP is H2[TcCl6](TBP)4. The distribution coefficients of aqua complexes of [TcCl6]2− were found to be in the order of [TcCl4(H2O)2]<[TcCl6]2−<[TcCl5(H2O)].

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Abstract  

The solvent extraction of technetium from urine with TBP has been investigated. The distribution ratio of technetium was determined as a function of HCl concentration and reaction time. The distribution ratio in the HCl-TBP system containing urine is consistently lower than that without urine. The chemical forms of technetium in urine, analyzed by paper chromatography, indicated that pertechnetate was reduced in the presence of HCl and that the reduction of pertechnetate was enhanced by urine. The observed decrease in the distribution ratio was attributed to the enhanced reduction of pertechnetate by urine.

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Abstract  

Endohedral 133Xe-higher fullerenes (133Xe@C76 and 133Xe@C84) were produced by implantation of 133Xe ions using an isotope separator. A high performance liquid chromatography (HPLC) analysis showed that the peak of endohedral 133Xe-higher fullerenes shifted backward from that of empty fullerenes, suggesting a possibility of the separation of endohedral 133Xe-higher fullerenes from empty fullerenes. The yields of endohedral 133Xe-fullerenes were in the order of 133Xe@C76<133Xe@C84<133Xe@C60<133Xe@C70.

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Abstract  

We determined 137Cs concentrations in deep water samples of the subtropical gyre in the South Pacific collected during the BEAGLE2003 cruise. This was done at an underground facility to achieve extremely low background γ-spectrometry, and we, therefore, obtained reliable values of 137Cs activity in the deeper layers. 137Cs activity in the layers between 2000 and 4500 m ranged from 7 ± 4 mBq m−3 to 25 ± 11 mBq m−3. The inventory of 137Cs in the water column from 2000 m to the sea bottom was estimated to be 20 ± 8 Bq m−2 to 94 ± 41 Bq m−2 in this region.

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Abstract  

The151Eu Mössbauer spectra were measured of surface-oxidized europium/II/ sulfate with the γ-ray transmission- and conversion electron technique. The comparison of such spectra demonstrated that the change in the oxidation state of trace amounts of europium induced by surface reactions could be characterized by the conversion electron Mössbauer technique. The photochemical reduction of europium/III/ oxalate to a Eu/II/species after irradiation with a low-pressure mercury lamp was demonstrated by means of this technique as well as ESR.

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Abstract  

A hexacyanoferrate(III) salt [N(C2H5)4]3[Fe(CN)6].5H2O (1)crystallized in a monoclinic space group (P21, Z = 2) with the nearest neighboring Fe-Fe distance of 8.20 Åound 1 distinctly showed magnetically-relaxed 57Fe Mössbauer spectra below ca. 40 K. The Mössbauer line width at 4.2 K was much larger than that of K3[Fe(CN)6], which is ascribable to the long Fe-Fe distance in 1. Further broadened spectra were observed for [N(n-C4H9)4]3[Fe(CN)6].xH2O (2).

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Abstract  

A rapid separation method was developed for determination of low level promethium-147 and samarium-151. The rapid method, applied to environmental samples, provided speed and efficiency for the respective separation of Pm and Sm from other lanthanides with the simplified technique of high performance liquid chromatography (HPLC) system. The separation time of Pm and Sm in HPLC separation was shortened by stepwise eluent method of -hydroxyisobutyric acid as compared with a gradient eluent method of lactic acid with HPLC despite increase in sample volume for significant determination of Pm-147 and Sm-151. This method permitted the detection limit around 0.1 Bq/kg-dry-soil for Pm-147 and Sm-151 in 200 g soil sample by counting for 500 min with a liquid scintillation counter.

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Abstract  

The radionuclide 67Cu was produced via the 68Zn(p,2p)67Cu reaction by irradiating enriched 68Zn targets with 70 MeV proton beam. Copper-67 was chemically separated from the zinc target by ion-exchange chromatography using Chelex-100 chelating ion-exchange resin. Procedure for recovery of the enriched 68Zn was developed. The target recovery yield of this method was evaluated to be more than 97%.

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Summary  

Hydrophilic endohedral 133Xe-fullerenols, [133Xe@C60(OH)xand 133Xe@C70(OH)x], were synthesized from hydrophobic endohedral 133Xe-fullerenes. The yield of endohedral 133Xe-fullerenols extracted in water was about 40% and 23% for C60and C70, respectively. The products stored in 0.9% NaCl solution at 20 °C were stable enough to be used in nuclear medicine.

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