[en] The characteristics of the adsorption of Co ion in water on activated charcoal impregnated with oxine have been studied. Impregnation of oxine largely improved the adsorption capacity of activated charcoal (AC), although the apparent initial and final adsorption rates are not affected. Another important advantage of AC impregnated with oxine [AC(HOx)] over plain AC is that Co ion collected on AC(HOx) is not easily eluted by flowing water. Furthermore the collection of Co on AC(HOx) is not affected by the presence of Fe(III), which exists in a macroscopic amount in waste water. At the initial adsorption stage, the apparent adsorption rate of Co ion on AC(HOx) is roughly proportional to 0.91 power of the concentration of Co ion. (author)

[en] A cyclic activation analysis method with a 100 μg ²⁵²Cf source was developed for the determination of low concentrations of fluorine in glasses containing high concentrations of oxygen. Factors influencing errors in the analysis were investigated quantitatively. The activation cross-section of ¹⁹F(n, α) ¹⁶N for ²⁵²Cf fission neutrons was determined. A brief description is given of the cyclic activation analysis apparatus and also the modified optimization of the cyclic operation. The usefulness of the analysis is demonstrated by application to a fluorine volatilization study. (author)

[en] A simple and safe procedure using the radioisotope dilution method for determining the mercury amount in electrolytic cells in the soda industry, has been investigated. The procedure developed is based on the correct supply by the Japan Atomic Energy Research Institute of the aliquots of radioactive mercury i.e. ¹⁹⁷Hg, precisely weighed and the standard reference sample accurately diluted. A high accuracy was achieved with the s.d. in the determination less than 1 %. (author)

[en] One method of solidifying inorganic radioactive waste, such as incinerator ash, is the hydrothermal solidification method. The advantage of this method is that the conditions of solidification are comparatively mild, compared with an ordinary hot pressure sintering, and that solidified bodies similar to ceramics can easily be obtained in a closed system. In the past, several studies on this method were conducted using non-radioactive simulated waste. Evaluation of leachability, the degree of contamination of an autoclave used, and also establishment of the handling technique for radioactive incinerator ashes as well as their solidified bodies are now urgently desired. In this study, leaching experiments were carried out by the use of an industrial incinerator ash impregnated with /sup 137/Cs and /sup 60/Co as tracers and a radioactive incinerator ash generated from a nuclear facility. In addition, an engineering scale test plant was built to obtain the necessary engineering data for full scale plants

[en] An in-stream gauge based on measurement of Compton-scattered γ-rays has been developed for determination of raw material density at a sintering plant in the steel industry and successfully applied to a sintering plant at the Kimitsu Works. The accuracy, stability and effectiveness of the gauge under on-line conditions have been confirmed by a long-run test. (author)

[en] The method of neutron activation was used to multi elementally analyze agar-agar. Twenty four elements were discovered and quantitatively determines. In comparison with the ultrapure agar-agar of Merck, the agar-agar from Glucaric spp. contains elements, except Cl, Br, I, Na and K, in higher proportions, and contains elements approximately in the same proportion as that of the agar-agar of Kant o Chemical Company. The result of this analysis is useful in the development of agar-agar from Gracilaria spp. as the one to be used in biotechnology research

[en] Active nanocrystalline nitrides of EuN and YbN with high surface areas were successfully prepared by the thermal decomposition of the rare earth amides (Eu(NH₂)₂, Yb(NH₂)₂ and Yb(NH₂)₃). For the preparation of CeN, PrN and NdN, the direct reaction of the rare earth metals with ammonia was extensively studied to determine optimal conditions. In the reaction of rare earth metals with ammonia, hydrides besides the nitrides were competitively formed. The reaction conditions such as temperatures and ratios of ammonia to rare earth metal were crucial in preferential formation of nitride. The nanocrystalline YbN and EuN readily absorbed large amounts of ammonia even at room temperature upon contact with ammonia (13.3 kPa). The absorbed ammonia existed in at least two forms on/in the nitride; the one was surface-adsorbed ammonia and the other ammonia absorbed in the nitride in a decomposed state. The properties of ammonia absorbed by the nitride were further evaluated by temperature-programmed desorption (TPD), FT-IR and XRD techniques

[en] Nanocrystalline rare earth nitrides (EuN and YbN) were successfully prepared by the thermal decomposition of amides (Eu(NH₂)₂, Yb(NH₂)₂ and Yb(NH₂)₃). The formation processes of nanocrystalline nitrides were characterized by X-ray diffraction analysis (XRD) combined with temperature-programmed desorption (TPD) techniques. The amides were first decomposed to form imide with evolution of NH₃ and subsequently the conversion into nitride occurred. The surface areas increased markedly with increase in temperatures and went up to 146 m² g^-1 upon thermal decomposition of Yb(NH₂)₂ to YbN around 773 K, while EuN obtained by the thermal decomposition of Eu(NH₂)₂ at 573 K yielded surface areas of 107 m² g^-1. Such nanocrystalline YbN and EuN readily reacted with ammonia even at room temperature upon contact with ammonia (0-4.67 kPa). The properties of ammonia taken up by the nitride were evaluated by TPD and XRD. XRD of the NH₃-treated YbN showed diffraction peaks shifted to lower angles, indicating that the ammonia molecules entered the crystal lattice with the expansion of crystal constants