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- Author or Editor: N. Nakamura x
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Abstract
The synergic extraction of La(III), Nd(III), Sm(III), Tb(III) and Lu(III) with 0.1M acetylacetone (Hacac) and 1,10-phenanthroline (phen) in benzene was studied. The adduct formation constant, 
s, for RE(acac)3 (phen) in benzene was determined. The
s decreases with inceasing atomic number of RE(III). The
s in different organic solvents can be predicted in connection with the activity coefficients of the solutes, and the validity of this prediction is confirmed by good agreement with the experimental values of
s in carbon tetrachloride and heptane.
Abstract
The generation of HF with traces of TF and then conversion to HT were investigated using a bed packed with NiF2 and Zn or Fe particles. When the temperature of fine particles of Zn or Fe was elevated up to 400 °C or 550 °C, respectively, TF was completely reduced to HT. Since ZnF2 and FeF2 had no TF (and HF) adsorption capacity, memory effect was found to be negligibly small. Thus Zn and Fe particles can be used as an effective reduction material corresponding to different temperature conditions to convert TF to HT for tritium detection by ion chambers without any corrosion.
Abstract
The substoichiometric separation of Yb(III) can be achieved by the extraction of a substoichiometric amount of thenoyltrifluoroacetone and an excess amount of phenanthroline in benzene. The appropriate pH range for the substoichiometric extraction is 6–8. The reproducibility of the substoichiometric extraction of Yb(III) is very good as RSD 1%. As an example, Yb in a manganese nodule is determined by the substoichiometry combined with the radioactivation analysis. The content of Yb is 17.63±0.23 
g/g. The present procedure can be applied to the determination of other rare earth elements.
Abstract
The substoichiometric isotope dilution analysis for manganese(II) in a synergistic extraction system of a chelating agent and a neutral ligand is described. The substoichiometric extarction is based on a substoichiometric amount of 2-thenoyltrifluoroacetone and an excess of 1,10-phenanthroline. The recommended condition and the reproducibility of the present system were examined. The present method was applied for NBS-SRM tomato leaves and NIES-SRM chlorella, and very good results with high accuracy and precision were demonstrated.
Abstract
Synergistic effect of neutral bidentate ligands, L, such as 1,10-phenanthroline(phen), 2,9-dimethyl-1,10-phenanthroline(dmp), and 2,2
-bipyridine(bpy), and of neutral unidentate ligands TBP and TOPO have been studied in the extraction of Mn(II) labeled with54Mn, using 2-thenoyl-trifluoroacetone(HTTA) in various organic solvents. The following factors play an important role in the synergistic extraction involving bidentate ligands; two-phase partition of bidentate ligands, their protonation and complex formation with Mn(II) in the aqueous phase. The mixed ligand complex, Mn(TTA)2L, is formed in all bidentate ligand systems. The adduct formation constant (
S,1) decreases in the following order; phen (lg
S,1=12.64) > dmp(11.32)> · bpy(8.54) in the cyclohexane system. This order is ascribed to the bacisity and the steric effect of the bidentate ligands. Organic solvents influence both the adduct formation and the partition of the ligands, and
S,1 decreases in the order cyclohexane>carbon tetrachloride>chlorobenzen 
= benzene>chloroform.
Abstract
In dealing with phenomena which show a linear response such as viscoelastic or dielectric properties, measurements are carried out by observing the relationship between the stimulus applied to the sample and the response from the sample. Since the Fourier analysis technique is effective in obtaining this relationship, two types of circuitries based on Fourier analysis have been created. Both DMA and dielectric measurement were used to evaluate these circuitries. Results were satisfactory, especially with respect to tanδ precision.
Abstract
A highly precise and accurate method for the determination of minor amounts of iron by substoichiometric isotope dilution analysis is described. The constant amount of Fe(III) is substoichiometrically extracted with 2·10−4M oxine in chloroform from the aqueous phase of pH 9.2–10.0 containing 6·10−3M tartrate. The interfering ions such as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), can be removed by the preliminary extraction of Fe(III) from 7.5M hydrochloric acid solutions into isopropyl ether. The present method has been applied to the determination of iron in biological standard reference materials, i.e., the NBS Spinach (SRM-1570) and the NIES Pepperbush (SRM No. 1), and the results obtained are 548±9 ppm (NBS certified value: 550±20 ppm) and 193±4 ppm, respectively.
Abstract
Elemental concentrations of aquatic insect larvae and attached algae in an uncontaminated river were analyzed by instrumental neutron activation analysis (INAA) via the k0-standardization method. The aquatic insect larvae found were all intolerant species. No significant difference was observed in the elemental concentrations of aquatic insect larvae and attached algae along the river. Similar elemental concentrations were observed in the aquatic insect larvae collected at a fixed sampling point for two years. An analysis by the ratio-matching technique indicated a higher generic relationship between aquatic insect larvae and attached algae than river water.
Abstract
Tritium concentrations were analyzed for coastal seawater and lake water collected from various places in Japan. Low tritium concentrations were observed for coastal seawater of small islands and it was attributed to a short residence time of the ground-water in such a small island. Tritium concentrations in lake water showed a significant variation. And it was revealed that the size of the lake and its drainage area were the dominant factors controlling the tritium concentrations in lakes.
Abstract
Accumulation of radiosilver108mAg and110mAg in oysters (Crassostrea gigas) and their behavior in marine environments has been studied in the northeast Pacific coast in Japan. Enrichment of radiosilver in oysters depends on topographical conditions; significant bioaccumulation occurred in open bays, while it was hardly observed in bays with narrow shaped entrances. From these observations difference of the behavior of radiosilver between open and nearly closed bays is suggested.110mAg in oysters decayed with an effective halflife of about 150 days for both the Chinese nuclear weapon test and the Chernobyl accident. In contrast to radiosilver, the fission product nuclide137Cs was almost independent of topographical conditions, and its concentration was constant.110mAg bioaccumulation in oysters after the Chernobyl accident in 1986 was found in both open and nearly closed bays, the latter showing much lower concentration of radiosilver than the former. Specific activity of108mAg in oysters was determined in bays open to the Pacific Oceans.
