In order to reveal the reactivity of a functional group in an aromatic compound having two substituents in the aromatic ring, the hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritiated water vapor (HTO vapor) and 3-amino-4-methoxybenzenesulfonic acid (and 2-aminotoluene-5-sulfonic acid) was dynamically observed at 50°C (and 70°C) in a gas-solid system. Consequently, the specific activity of the acid increased with time, and it showed that the T-for-H exchange reaction occurred. Applying the A″-McKay plot method to the data observed, the rate constant of each functional group for the reaction was obtained. After the additive property of the Hammett's rule was applied to this work; the new substituent constants were obtained. From the above-mentioned, the following four items have been confirmed. (1) The reactivity of the functional groups can be dynamically analyzed, and the A″-McKay plot method is useful to analyze the reactivity. (2) The additive property of the Hammett's rule is applicable to quantitative comparison of the reactivity of the functional groups. (3) The reactivity of the functional groups can be simultaneously analyzed by using the A″-McKay plot method in the T-for-H exchange reaction. (4) The method used in this work is also useful for analyzing the reactivity of a certain material having some kinds of functional groups.
Oxygen stable isotopic ratios (δ18O) of the precipitation and some river water samples in Niigata prefecture were measured from 1999 to 2002. Isotopic measurements were performed by a stable isotope ratio mass spectrometer. Consequently, the following matters were found. (1) The mean δ18O value of precipitations was -9‰, and the variation of ±7‰ was shown throughout the year. (2) All of 9 observation points, the seasonal behavior of isotopic ratio was similar to each other. (3) In June and January, δ18O value o f precipitations was small, and was large in August. (4) In January, the relationship between the temperature of observation points and δ18O values in precipitation was most remarkably found throughout the year. (5) The variation of δ18O values in precipitations in winter is smaller than that in the other seasons. (6) The mean δ18O value of river waters in Niigata prefecture was about -11‰ to -10‰, and the variation was not so large (±2‰) throughout the year. (7) δ18O values of river waters may vary when the melted snow or the precipitation flow into the rivers. (8) The variation of δ18O values in groundwater was smaller than that in river waters.
PIXE (Particle Induced X-Ray Emission) analysis provides the rapid determination of major, minor and trace elements in very small amounts of solid samples. We examined, the minimum amount of samples required and the precision of PIXE analysis as well as its validity and limitation for river water samples. Several elements in soluble materials from the reference river water samples were determined by PIXE analysis. Such elements as Mg, K, Ca, Cr, Cu, Se and Pb were obtained almost the same concentration as these certified values. PIXE analysis for the suspended solids (SS) separated from the river water of several selected sites along the Hinuma River, Ibaraki prefecture, Japan, showed, the presence of more than 10 elements in almost all samples. The comparision between PIXE analysis and ICP-AES or ICP-MS analysis on the representative example of SS showed that the concentrations for Na, Mg, Al, K, Ca, Ti, Mn, Fe and Cu revealed the correlation among those analytical methods. It suggests that PIXE analysis is quite promising method for the simultaneous determination of Na, Mg, Al, Si, S, K, Ca, Ti, Mn, Fe, Cu, Br and Sr in a relatively short time by using the correction coefficients for self-absorption of X-ray without processing acid dissolution.
Effect of phantom material on backscattered radiations was studied for photon irradiation. Monte Carlo calculations using MCNP-4B code were performed to analyze scattered radiation on the surface of 30×30×15 cm3slab phantoms with different material. Dose on the surface of a human body was also estimated with a modified MIRD-5 type phantom. No significant difference of dose due to scattered radiation was observed between a soft tissue slab phantom and the water-filled slab phantom recommended by the International Organization for Standardization. On the other hand, dose on the surface of the PMMA phantom was found to be larger than doses on the phantom with water or soft tissue. The results also showed that response of dosimeter on the ISO phantom would be near to that on the trunk of a human body.