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  • Author or Editor: T. Ishii x
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Abstract  

By means of INAA, REEs in the dredged rocks from a seamount /KH73-4-2/ in the East Mariana Basin were determined. Based on the REE patterns, the rocks are classified into two groups despite of alteration: highly altered palagonite of oceanic-island tholeiitic nature, and relatively fresh basaltic-andesitic rocks of alkaline rock nature.

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Summary Thermally induced structural transformation of fibrous hydrogen-bonded molecular assemblage formed from an amphoteric pyridinecarboxylic acid of 6-[2-propyl- 4-(4-pyridylazo)phenoxy]hexanoic acid (C5PR) was studied using differential scanning calorimetry (DSC), differential thermal analysis (DTA), and thermogravimetry (TG). The organized fibrous morphology formed in an aqueous solution was stable at temperatures below 150°C. The ordered crystalline solid phase (K1) of the original fibrous material altered to a disordered crystalline solid phase (K2) at 150°C and subsequently to an isotropic phase (I) at 172°C. In the isotropic state, the C5PR molecule was slowly decomposed by decarboxylation. Once the molecular assemblage was subjected to the mesophase by heating, another ordered crystalline solid phase (K3) appeared reversibly at 17°C. The heat budget analyses by DSC indicated that a conformational entropy change such as the side-chain propyl group and the main-chain pentamethylene unit in the hydrogen-bonded molecular assemblage took place between the two ordered crystalline solid phases K1 and K3.

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Abstract  

The thermally induced structural transformation of a hydrogen-bonded crystal formed from an amphoteric molecule of 6-[2-methoxy-4-(pyridylazo)phenoxy]hexanoic acid MeO was studied using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction measurement (XRD). Crystal form of the hydrogen-bonded crystal was measured by single crystal four circle diffractometer (Mo-Kα radiation). As a result, the crystal of MeO was stabilized by many C–H⋅⋅⋅O hydrogen bonds, and the C–H⋅⋅⋅O hydrogen bonds were broken by thermal energy reversibly. After transformation the supramolecular architecture was composed of supramolecular polymer including free-rotation pentamethylene main chains.

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Abstract  

Lanthanides in altered oceanic tholeiite were determined by means of instrumental neutron activation analysis. Potassium content was employed as a measure of degree of alteration. Lanthanide concentrations in moderately altered parts of tholeiite (K2O content below 1%) were identical with those in'unaltered parts while light lanthanide concentrations in more altered parts (K2O content above 1%) increased with degree of alteration.

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Abstract  

In this study, GdBaSr(Cu3−x M x)O7−δ bulk samples (M=Zn and Ni; 0≤x≤0.1) were prepared via solid-state reaction. Specific heat measurement (measured with thermal relaxation technique using PPMS) shows an obvious specific heat jump around the T c for GdBaSrCu3O7−δ sample as observed in most of the high temperature superconductors. It shifts towards lower temperature with increasing of both Zn and Ni doping contents, whose tendency is similar to the decreasing of T c. Debye temperature, ΘD (derived from specific heat measurements) calculated at around 10 K is found to be directly proportional to the T c.

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Abstract  

The stability constants (b1) of the monofluoro complex of Cm(III) have been determined in mixed solvents of methanol and water using the solvent extraction technique. The values of lnb1 increase as the molar fraction of methanol (Xs) in the mixed solvent increases. The variation in the stability constants mainly depends on the solvation of F- and slightly depends on both (1) the solvation of cations in connection with the complexation of CmF2+ and (2) the electrostatic attraction of Cm3+-F-. The variation in lnb1 for Cm(III) due to the effect of both (1) and (2) is similar to that for Sm(III). By variation of lnb1 the coordination number in the primary hydration sphere (CN) of Cm(III) decreased from a value between CN = 9 and CN = 8 to CN = 8, at about Xs = 0.02. The Xs value of the inflection point of the CN for Cm is slightly lower than Xs = 0.06 for Sm(III) and Xs = 0.03 for Eu(III), previously obtained.

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