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- Author or Editor: E. Inoue x
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Abstract
The diffusion coefficients of Sr in gelled silica gel layers have been measured at various porosities. They decreased with the second power of porosity. At constant porosity, the diffusion coefficients of Sr and Co were measured at various pHs. They were dependent on the distribution coefficients (K) of the species between silica gel and pore water as a function of 1/(1+K). Gelation of the porous layer enables a stable measurement of diffusion coefficients under various conditions and facilitates the analysis of the distribution of ions after the diffusion experiments.
Abstract
TG studies are given for PMMA prepared by radical polymerization, PTHF prepared by cationic polymerization, and their blends. A procedure is proposed for determining the activation energy, frequency factor, and the order of events corresponding to the respective stages of the multistage TG curves. The order of the initial event of PMMA is not the 1st. It is shown for this discussion that the relationship between mass loss and time of the 2nd order reaction is similar to that of the depolymerization including the vaporization process at the earlier times. Some of TG curves of PTHF are not dependent on the heating rate. This independence depends on the size of sample. The order of event of PTHF, which is obtained from TG curves dependent on the heating rate, is the 0th. The event order equal to the 0th reflects major contribution of vaporization in the event. The TG behaviors shown by the procedure mentioned above for the PMMA/PTHF blends with the smaller PMMA or PTHF contents cancel those of PMMA or PTHF.
Abstract
Mössbauer spectra of /pheophytinato a/ iron/III/ chloride [Fe/Pheo-a/Cl] and /pheophytinato b/ iron/III/ chloride [Fe/Pheo-b/Cl] have revealed that the central iron/III/ ion is in a high-spin state and axially coordinated by chloride ions in solid phase. Temperature-dependent asymmetry observed for the quadrupole splitting doublet of iron/III/ pheophytins, i.e., Fe/Pheo-a/Cl and Fe/Pheo-b/Cl, is interpreted on the basis of the zero-field splitting. The structural difference between iron/III/ pheophytins and iron/III/ porphyrins is reflected in the quadrupole splitting more than in the isomer shift. Magnetic behaviour of iron/III/ pheophytins near 4.2 K is very similar to that of iron/III/ porphyrins.
Abstract
DSC studies are given for polytetrahydrofurans with molecular masses equal to 650, 1400, and 2900, for their blends, and for their cured samples. The samples were stored, annealed, and quenched to obtain the samples with different thermal histories. Two or more endothermic peaks appear in the DSC curves for the stored samples, even for the non-blended samples. A hyperbolic curve forced the plot of the highest melting temperature vs. the molecular mass to asymptote to about 50C. The relationship between the highest melting temperature and the composition for the blended samples is suitable to linear or Fox’s relation. A peak and a shoulder appear in the DSC curves of the cured samples. As the samples are cooled at the faster rates in the thermal treatment, the shoulder appears at the lower temperatures.
Abstract
/Pyropheophytinato a/ iron/III/ chloride [Fe/Pyropheo-a/Cl] and /pyropheophytinato b/ iron/III/ chloride [Fe/Pyropheo-b/Cl] have been prepared and characterized by Mössbauer spectroscopy. The Mössbauer parameters of the iron/III/pyropheophytins are similar to those of iron/III/ porphyrins. A comparison of the quadrupole splittings for the iron/III/ pyropheophytins with those for the iron/III/ pheophytins suggests that the deviations of the cyclopentenone ring and the saturated pyrrole ring from the macrocyclic plane become smaller with the removal of the methoxycarbonyl group.
Abstract
In order minimize the possible contamination during storing and pre-treatment of such pure samples as ice and snow collected in Antarctica, trace elements in experimental tools such as bottles, beakers, tubings and filters were determined by neutron activation analysis. By using well certified tools, ice and snow samples from Antarctica and high mountains in China and in Japan were analyzed. Relative concentrations of volatile elements such as Zn, Cd, As, Sb or Ag to Al or Fe which are major components in the earth crust were found to be 10 to 1000 times higher than in the ordinary soil for the samples from Antarctica and Mt. Naimonanyi in China.
