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Abstract  

The extraction behavior of Eu(III) has been studied using di(2,4,4-trimethylpentyl)phosphinic acid (DTMPPA, HA) in kerosene. Europium was extracted as Eu(HA2)3 with the extraction constant of 2.0·10–3. This extraction system was applied to the transport of Eu(III) across a DTMPPA liquid membrane supported on porous polytetrafluoroethylene. Europium was quantitatively moved through the liquid membrane containing 0.1M (HA)2 as a mobile carrier from the feed solution of pH above 3 into the product solution of 0.1M HNO3, yielding a concentration factor of ten. The transport rate increased with increasing pH and DTMPPA concentration.

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Abstract  

207Bi and other fallout nuclides /137Cs and60Co/ in sea sediments were measured, and other quantities were plotted against ignition losses of the samples which were separately determined by gravimetry. For each nuclide radioactivity was closely correlated to the ignition loss of the sample. A similar relation was nearly hold good for the amount of stable lead and the quantity of organic carbon. From the results a probable mechanism of sedimentation is suggested.

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Abstract  

Radiochemical techniques have been applied in various ways to the study of fullerenes and metallofullerenes for the past several years, and they have provided invaluable information pertaining to the stability, structures, and formation of the novel carbon material. This paper reviews those experimental results that have fully shown the usefulness and uniqueness of radionuclides demonstrated in the field of fullerene science.

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Abstract  

The (pX, X) technique is a very reliable tool for trace element analysis when large amounts of a neighboring element are present. This paper describes the experimentally determined detection limits of some available sources of GaAs, Ge and Zr, to evaluate the utility of this technique. The theoretical detection limits calculated with a computer program are also described.

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Abstract  

Adsorption of carrier-free radiotracers 181W and 93mMo produced in the 181Ta(p, n) and natNb(p, n) reactions, respectively, on anion-exchange resin was studied in mixed solution of HF and HNO3 in a concentration range of 10−4–10−1 M HF/0.1 M HNO3. Distribution coefficients (K d) of 181W and 93mMo at 70 °C showed the V-shaped variation with the minimum at around 10−1 M HF/0.1 M HNO3, although variation of the K d values for 93mMo was quite small compared with that for 181W. Formation of oxofluoro complexes for W and Mo is briefly discussed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: K. Kitamura, Y. Imazawa, T. Morimoto, K. Sato, H. Higuchi, K. Imai, and K. Watari

Abstract  

Thorotrast was widely used in the past as an X-ray contrast medium, containing a colloidal solution of thorium dioxide (232ThO2). After injection, thorium accumulates and is mainly retained in the liver. Thus once Thorotrast is administered, patients might be chronically exposed to -radiations. Recently, significant development of cirrhosis and cancer of the liver has often been noted among Thorotrast patients. Additionally the incidence of lung and breast disease has significantly increased. Thus, the assessment of internal radiation dose from deposits of Thorotrast is very important. In this report, the thorium content in various organs was determined by means of neutron activation analysis. All the samples were taken from organs of Thorotrast patients subsequent to death. The ashed samples were irradiated in a reactor. After cooling, the content of thorium was determined by measurement of gamma rays resulting from the decay of protactinium-233. For comparison, measurements by other analytical methods such as inductively coupled plasma mass spectrometry, colorimetric analysis using ArsenazoIII and radiation measurement of -rays from actinium-228, were carried out.

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Abstract  

Some improvements of the detection sensitivity in pulse time interval analysis (TIA) based on selective extraction of successively - correlated decay events within millisecond order from random or background events, were established by the utilization of PSD, to reject /-pulses from -ones and a simple chemical procedure of radium separation, together with the use of well resolved scintillator. By applying the PSD, the contribution of -decay events was completely eliminated in both the -spectra and the TIA distribution curves as well as the improvement into clear energy resolution and the enhancement of detection sensitivity for the TIA. As a result, the TIA and -spectrometric analysis of226Ra-extract showed the existence of223Ra (Ac-series) and /-correlated events with correlated life (due to 0.16 ms due to214Bi() 214Po()) along with a singly well resolved -peak to be useful for the determination of226Ra (U-series). The difference of half-lives (145 and 1.78 ms) due to216Po and215Po (direct daughters of224Ra for Th-series and223Ra for Ac-series, respectively) was also proven for the possibility of the simultaneous determination of both correlated events by using the TIA/PSD combined with chemical separation and liquid scintillation counting method. Finally, the simultaneous determination of three natural decay series, which include U-, Th- and Ac-series nuclides, have been conveniently carried out for some environmental samples using the present method combined with225Ra yield tracer (Np-series).

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Abstract  

Mixed-valence states of57Fe-atoms produced after EC-decay of57Co in oxo-centered trinuclear cobalt-iron carboxylates have been studied by means of emission Mössbauer spectroscopy. The emission Mössbauer spectra show nearly the same temperature dependence of the mixed-valence state as found in the absorption Mössbauer spectra of the corresponding trinuclear iron carboxylates. The results indicate that most of the decayed atoms keep their position at the sites of original57Co atoms.

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Abstract  

A simplified method for the substoichiometric analysis of phosphorus has been developed and applied to determine the concentration distribution of phosphorus in the region of a SiO2–Si interface in order to explain why phosphorus is lost from the ion-implanted silicon surface throughout the oxidation and oxide removal processes. It is revealed that phosphorus piles up on the SiO2 side at the interface by the thermal oxidation of silicon surface and is removed with the oxide by wet etching and with the resulting silicon by RCA cleaning. This results in a total loss of ion-implanted phosphorus of 3.5%.

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Abstract  

The crystal structures of oxo-centered trineclear cobalt-iron chloroacetate complex [CoIIFe 2 III O(CH2ClCO2)6(H2O)3]·3H2O (1) was compared with that of previously reported trinuclear iron complex [FeIIFe 2 III O(CH2ClCO2)6(H2O)3]·3H2O (2) which has an isomorphous structure to 1. Compound 1 crystallizes in space group P21/n with Z=4 in a unit cell of a=14.826 (4) Å, b=4.536 (8) Å, c=14.000 (4) Å, =100.32 (2)0 and V=2968 (11) Å3. The structure was refined to R=0.75 and Rw=0.82. The coordination geometries of the three iron atoms are observed equivalent in 1 indicating a static disorder of the position among cobalt and iron atoms. Two distinct FeIII doublets observed in Mössbauer spectra of 1 become an indistinguishable broad doublet by dehydration of crystal water. On the other hand, no significant line-broadening is observed after the dehydration in complex 2. The results indicate that the dehydration in 2 induces a local environmental change reordering of an electronic configuration around iron atoms, whereas the remaining disordering is reflected in Mössbauer spectrum after the dehydration in 1.

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