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  • Author or Editor: T. Suzuki x
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Abstract  

Ingrowth of60Co radioactivity in an iron sample irradiated in a nuclear reactor has been measured for determination of formation cross section of60Fe in the59Fe(n, )60Fe reaction with reactor neutrons. After 5 years cooling, the irradiated iron was purified from60Co and other radioactive nuclides by an anion exchange separation method and isopropyl ether extraction in hydrochloric acid. The amount of60Co ingrowth was measured by -spectrometry using a Ge-detector coupled to a multichannel pulse height analyzer 4 years after the purification of iron. Neutron flux of the irradiation position was calculated from the amount of55Fe produced. The observed value of 12.5±2.8 barn is slightly greater than reported value for burnup cross section of59Fe(n, x)X, where x refers , , d, p and 2n, and X is any nuclide produced by the above reactions.

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Abstract  

Trace elements such as Sc, lanthanoids, Th and U were determined by means of instrumental neutron activation analysis (INAA) in marine sediment core samples collected from 5 coastal areas in western Japan mainly facing the Pacific. The origin of the coastal sediments and the sedimentary environment are discussed in terms of such parameters as the La*/Lu* and Ce*/La* ratios, the Th/Sc ratios and the Th/U-Ce/U plot obtained from the analytical data. In particular, it was confirmed that the Th/U-Ce/U plot introduced in this work is extremely useful for estimating the sedimentary environment, including redox conditions.

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Abstract  

Cu-di-(2-ethylhexyl)phosphate was used as the cation exchange extractant from molten nitrate salt. IR absorption spectra of di-(2-ethylhexyl)phosphoric acid and Cu-di-(2-ethylhexyl)phosphate were compared and it was proved that the acidic form of the extractant is not Cu-di-(2-ethylhexyl)-phosphate. Using LiNO3−NH4NO3 eutectic melt, it was shown that the back-extraction of Cu2+ is a cation exchange reaction. Np(V) and Pa(V) were extracted by Cu-di-(2-ethylhexyl)phosphate from LiNO3−NaNO3−KNO3 eutectic melt. The distribution ratio of Np(V) was greater than that of Pa(V) on the contrary of their distribution ratios in the aqueous extraction system. A possible cation exchange extraction reaction was proposed for the extraction of Np(V).

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Abstract  

Scanning thermal microscopy (SThM) can measure thermal image with a nano-scale spatial resolution. However, there remains an issue in quantitative temperature measurement. We proposed an active temperature measurement method that provides a real temperature image by compensating a variation in contact thermal conductance. Performance of the active method was examined by a multi-function cantilever made with micro-fabrication process. Response test of the cantilever showed about 50 Hz cut off frequency for both passive and active method. Temperature measurement test indicated that sensitivity of heat flow detection was not enough to measure real temperature regardless of the thermal contact conductance. Imaging test demonstrated that the active method takes temperature image closer to real temperature distribution than the passive method.

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Abstract  

The relative gamma-ray intensities in the energy region between 122 and 411 keV in the decay of152Eu were measured by using a Ge(Li) detector. Its efficiency calibration was carried out with the radioactive sources of241Am,57Co,203Hg,137Cs,133Ba,75Se,169Yb and192Ir.

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Summary  

We investigated the influence of ionic strength on migration behaviors of Sr and Eu in the presence of humic acid (HA). The breakthrough curve of Sr through a quartz sand column in the presence of HA was identical to that in the absence of HA. Europium migration in quartz sand was enhanced by the presence of HA at low ionic strength. At high ionic strength, Eu migration in the presence of HA was hindered compared to that in the absence of HA. Adsorption of europium on quartz sand in the absence of HA decreases with increased ionic strength.

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Abstract  

Polyethyleneglycol (PEG) and its derivatives of high molecular weight were found to be employed as useful extractants for the solvent extraction of uranium. The extraction behaviors of uranium and neptunium were investigated, particularly concerning the dependence of the extractibility of uranium(VI) on the molecular weight of PEG. A dominating species of the extracted uranium(VI) thiocyanate complexes was assumed to be NH4 UO2(SCN)3·(PEG). The extraction of protactinium was also preliminarily studied. The extraction of these actinides from an acidic thiocyanate solution increased in the order: uranium(VI)>protactinium(V)>neptunium(V).

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Abstract  

Evidence is obtained to show that the liquidliquid extraction separation of99mTc from99Mo with methyl ethyl ketone, methyl propyl ketone and methyl isobutyl ketone can be transformed into a solid-phase column extraction procedure. The aqueous alkaline99molybdate solution is immobilized on a column of a granular large-pore diatomaceous earch support, which is the neluted with the abovementioned extractants. Rapid and clean separation of99mTc can be with all three solvents. The99mTc can be back-extracted from the organic phase on a column filled with distilled water /or saline/ loaded granular diatomaceous earth /Extrelut®/. The possibility of using the abovementioned procedure as a basis for a new99mTc/99Mo generator concept is envisaged.

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Abstract  

The interaction of Ra2+, Sr2+ and Ba2+ with 1,4,7,10,13,16-hexaoxacyclooctadenace /18-crown-6/ in an aqueous solution was investigated by radio- and dc polarography. It was found that all these ions form 11 complexes with 18-crown-6 and their stability constants, lg K, are 3.43 for Ra2+, 2.40 for Sr2+ and 3.67 for Ba2+, respectively. The stability constant for Am2+ was estimated from the relationship between lg K for Sr2+, Ba2+, Ra2+, Eu2+, Yb2+ and Cf2+ and the ionic radii.

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Abstract  

Extraction behaviour of lanthanoid/III/ has been investigated by using 18-crown-6/CR/ as a neutral microcyclic ligand, trichloroacetate/TCA/ as an anionic counter ion, and 1,2-dichloroethane as an organic solvent. From the equilibrium studies, the extractable complex such as LnCR3+ was found for La/III/, Ce/III/, Pr/III/, Nd/III/, Sm/III/, and Eu/III/ and also the formation of Ln/CR/ 2 3+ complexes was suggested for Tb/III/, Tm/III/, and Lu/III/. The extractability of lanthanoid/III/ steeply decreased with increase in the atomic number. This order of extractability was a reverse trend compared with that in many other extraction systems reported so far. Very high separation factors especially among light lanthanoid/III/ were observed.

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