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  • Author or Editor: T. Sekine x
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Abstract  

Extraction of ionic solutes in aqueous solutions into various organic solvents is reviewed by showing several examples. The extraction of strong acids into polar organic solvents and nonpolar solvents containing hydrogen-bonding extractants is described as the first example and the extraction of simple metal salts into strongly dielectric or solvating polarsolvents and nonpolar solvents containing solvating extractants is then reported. Finally, the solvent extraction of anionic metal complexes with bulky cations into nonpolar solvents as ion-paris is described and the statistical method for such extraction equilibria is considered.

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Abstract  

An analytical function for describing the response function of γ-rays from the NaI(Ti) detector was constructed with the purpose of establishing the method of automatic γ-ray spectrum analysis. The response was found to be divided into six portions; the function of each portion joins smoothly to the one representing the adjacent part. Empirical equations for the parameters specifying the response function were found as functions of the γ-ray energy in relation to the detector dimension. The obtained response function was fitted to the observed spectrum by the least squares method. The calculated spectrum agreed well with the observed one.

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Abstract  

Possibility of negative muon transfer from helium muonide He + to T /or D/ through collisional excitation after muon catalyzed fusion has been pointed out. The transfer process depends on the efficiency of collisional excitation of He + in the medium of tritium or deuterium. It is argued that tritium has larger nuclear stopping power and better excitation efficiency than deuterium. This effect is in the same direction as the tritium concentration dependence of muon loss probability in recent experimental work.

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Abstract  

Hot atom chemistry in the past and at present is reviewed, and its future direction is considered. Though it has still important meanings in nuclear and radiochemistry studies, new ideas to improve the present situation are expected to emerge.

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Abstract  

Hot atom chemical reaction by50Cr/n, /51Cr and52Cr/, n/51Cr reactions, and recoil implantation reaction by51V/p, n/51Cr reaction were investigated using geometrical isomers /mer and fac/ of tris/benzoylacetonato/ chromium/III/ /Cr/ba/3/. The production of counter isomer was observed for both mer- and fac-targets, although the yield of labelled parent isomer was larger. The observed mer/fac yield ratio suggests that the main formation mechanism of51Cr/ba/3 is the reaction of ba and Cr/ba/ 2 + which has the same geometrical configuration of target complex, and the substitution reaction of central metal atom by recoil51Cr. Furthermore, implantation gave rise to a much higher yield of labelled Cr/ba/3 compared to the case of in situ nuclear recoils.

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Abstract  

Recoil implantation of Tc and Ru in metal acetylacetonates were performed using ruthenium metal as a source and MIII/acac/3 and MII/acac/2 complexes as catchers. The recoil atoms were obtained by100Ru/, p/99mTc and98Ru/, n/97Ru reactions. The yields of Tc/acac/3 and Ru/acac/3 were clearly dependent on the force constant of the bond between the central metal atom and oxygen in acetylacetone K/M–O/. A plot of the yield vs. 1/K(M–O) showed a linear relationship. However, the yield of Tc/acac/2 implanted in M/acac/2 did not show such a dependence on the force constant. The difference of the mechanism of complex formation between Tc/acac/3 and Tc/acac/2 was discussed on the basis of a reaction cage surrounding the recoil atom and of reaction time necessary for competition between the recoil atom and the central metal of the catcher complex.

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Abstract  

Self-shielding and burn-out effects are discussed in the evaluation of radioisotopes formed by neutron irradiation of a strongly-neutron-absorbing material. A method of the evaluation of such effects is developed both for thermal and epithermal neutrons. Results of the calculation are discussed in comparison with the observed yields of153Gd,160Tb, and161Tb for the case of neutron irradiation of disc-shaped targets of gadolinium oxide.

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Abstract  

Neutron emission has been examined in a system in which the recently reported phenomenon of fracto-fusion might be occurring. No positive evidence has been obtained for cold fusion. The upper limit of the fusion has been 0.0112 events/sec in each specimen containing 0.33 g D2O.

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Abstract  

TcN-EDTA has been synthesized for the first time starting from TcNCl4 . Elemental analysis shows that this compound has three molecules of water of crystallization: TcN(Hedta) · 3H2O. Its optical spectrum has an absorption maximum at 505 nm with = 1060 dm3.mol–1.cm–1. It decomposed easily under alkaline conditions.

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