[en] Complex formation of ⁹⁵Tc microquantities with humic acid is studied. Addition of Sn²⁺, used as a reducer to the mixture, containing ^95mTc, humic acid 0.1 mole/l NaClO₄ (pH 4), leads to simultaneous formation of technetium and aluminium complexes with formic acid (Tc-Ha, Sn-HA). The Tc-HA complex yield equals 50-70%. The results obtained make it possible to consider that the Tc-HA complexes constitute the basic technetium form, formed under reduction conditions, characteristic of depth subsoil waters, containing humic acid

[en] The set of ion sources covering the different aspects of the nuclear physics programme at the GSI ISOL is described with special emphasis on the ultra-high temperature discharge FEBIAD-F ion source, developed especially to improve the on-line separation of exotic nuclei in the region of the first series of transition elements. With the FEBIAD-F source as well as with the cavity-type thermoionizer nuclear spectroscopy was extended for several elements further from the β-stability line both on the neutron-deficient and neutron-rich side. Separation yields and overall efficiencies for short-lived and refractory species demonstrate our present-day state-of-the-art. (orig.)

No abstract available

[en] Quantitative and kinetic analysis of the immune-adherence reaction (IA) between C3b fragments and IA receptors as an agglutination reaction is difficult. Analysis is possible, however, by use of radio-iodinated bovine serum albumin as antigen at low concentrations (less than 200 ng/ml) and optimal concentration of antibody to avoid precipitation of antigen-antibody complexes with human erythrocytes without participation of complement. Antigen and antibody are reacted at 37⁰C, complement is added, the mixture incubated and human erythrocytes added; after further incubation, ice-cold EDTA containing buffer is added and the erythrocytes centrifuged and assayed for radioactivity. Control cells reacted with heated guinea pig serum retained less than 5% of the added radioactivity. The method facilitates measurement of IA reactivity and permits more detailed analysis of the mechanism underlying the reaction. (Auth.)

[en] 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 polar solvents 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-pairs is described and the statistical method for such extraction equilibria is considered. (author) 19 refs.; 7 figs.; 5 tabs

[en] By applying sublimation technique, the hot-atom ef--fect accompanied with (γ, n) reaction of 2,2,6,6-tetramethyl-3,5-heptanedione (H thd) complex of ²³⁷Np was studied to obtain the enriched ²³⁶Np and prepare ²³⁶Pu tracer effectively for environmental plutonium study. The enrichment of ²³⁶Np was realized in the sublimation residue and the enrichment factors were found, by the irradiation of either ²³⁷Np-thd complex itself or that with La carrier, to be 32.7 and 124.6, respectively. (author)

[en] Water soluble species of Tc nuclides which were produced by (d,xn) reactions of molybdenum and were implanted into acetylacetonate catchers were analyzed by cation-exchange chromatography and by gel chromatography with and without O₂. It was found that the decay products sup(99m)Tc and sup(96)Tc tended to form pertechnetate in comparison with the direct nuclear reaction product sup(95)Tc, and this leads to an apparent time-dependent isotope effect of chemical behaviours among the Tc nuclides. These nuclides were, however, found in cationic species in the absence of O₂. The effect was interpreted in term of electrostatic interaction between a positively charged technetium interstitial produced by the decay and O₂^- which could make technetium oxide as a precursor of pertechnetate. (author)

[en] Three kinds of acetylacetone complexes of technetium were synthesized by the following radiochemical methods; 1) sup(99m)TcO₂(acac)₂ by the β^-decay in ⁹⁹MoO₂(acac)₂; 2) Tc(acac)₃ by the (γ,p) reaction in Ru(acac)₃, and 3) Tc(acac)₂ by recoil implantation using (d,n) reaction in the mixture of molybdenum metal powder and Co(acac)₂ x 2H₂O. The technetium acetylacetonates thus produced were purified by vacuum sublimation technique, and some of their properties were investigated. (orig.)

[en] Replacement reactions of ruthenium recoil atoms have been studied with ⁹⁷Ru and ¹⁰³Ru recoil atoms produced by (γ,n) reactions in solid ruthenocene derivative complexes and their cyclodextrin inclusion compounds. The replacement reaction yields were inversely proportional to the square root of the average distance between two adjacent ruthenocene derivative molecules in solids. This relation was successfully explained by the replacement reaction model introducing the attacking probability; a probability of recoil atoms to attack the central atoms in ruthenocene derivative molecules through the geometrical open area of the sandwich structure. (author)

[en] The hydrolysis of Np(V) has been studied by way of determining the pH dependence of the solubility in the pH range from 7 to 13.8, for the ionic strengths of 0.1, 1.0, and 3.0 M NaClO₄, at a temperature of 25deg C. At high ionic strengths of > 1 M the amorphous phase of NpO₂OH changes into a thermodynamic, more stable, modified phase with a solubility that is reduced by the factor of 5.1. The determined solubility data are used for deriving the first and second hydrolysis constants at the different ionic strengths, and for both phases the solubility product is determined. The results show good agreement with earlier results obtained by the authors for I = 1.0 M, but reveal clear deviations from data found in the literature. The investigations of the complex formation of Np(V) with carbonate have been done by way of solubility measurements in the pH range from 6.5 to 10, for the ionic strengths of 0.1, 1.0 and 3.0 M NaClO₄, at a CO₂ partial pressur of 0.03% and a temperature of 25deg C. With lower ionic strengths, the solid phase is NaNpO₂CO₃, whereas with higher concentrations of Na₂CO₃, Na₃NpO₂(CO₃)₂ as a stable, solid phase is observed. The complexes NpO₂CO₃^-, NpO₂(CO₃)₂^3-, and NpO₂(CO₃)₃^5- develop as dissolved species. The solubility products and the complex formation constants of the dissolved species and of the solid phases are derived by numerical simulation of the solubility curves for the ionic strengths of 0,1, 1.0 and 3.0 M. The complexation constants thus obtained could be verified by absorption spectroscopy, for the complexes NpO₂CO₃^- and NpO₂(CO₃)₂^3-. (orig./BBR)