Authors:T. Yoshida, Y. Moriya, T. Tojo, H. Kawaji, T. Atake, and Y. Kuroiwa
The heat capacity of PbMO3 (M=Ti, Zr and Hf) at constant pressure was measured using a differential scanning calorimeter (DSC) from room temperature up
to 870 K. Large anomalies were found in the heat capacity curves, corresponding to the ferroelectricparaelectric phase transition
in PbTiO3 (PT), the antiferroelectric-paraelectric phase transitions in PbZrO3 (PZ) and PbHfO3 (PH). The transition entropies were estimated as 7.3 J K−1 mol−1 (PT), 9.9 J K−1 mol−1 (PZ) and 9.3 J K−1 mol−1 (PH). These values of transition entropies are much larger than that of a typical displacive-type phase transition.
Authors:N. Nogawa, K. Oohashi, H. Matuoka, T. Moki, T. Moriya, and N. Morikawa
Reactions of recoil tritium with benzoic acid, acetanilide and -phenethyl alcohol were studied using the3He/n,p/3H reaction. The tritium distribution in the aromatic ring is approximately uniform in all the irradiated compounds and the tritium activity per C–H bond in the methyl and ethylene groups is 7 to 8 relative to that of the corresponding ring as standard /=100/. These findings are substantially the same as those obtained previously by the6Li/n,/3H reactions, suggesting the same mechanism of tritiation for both recoil reactions. The tritiated parent compounds were obtained in high radiochemical yields; 45% for benzoic acid, 30% for acetanilide, 12% for -phenethyl alcohol.
Authors:G. Ferro-Flores, T. Moriya, F. Miura, H. Matsuoka, and K. Hoizumi
An efficient method to produce [1-14C] benzoic acid within a total time less than 20 min in high chemical and radiochemical yield is described. The procedure we report can be applied for the preparation of [11C]-labeled carboxylic acids suitable for evaluation in the study of human metabolism by positron emission tomography.