In order to quantitatively evaluate the influence of tritium(3H or T) in ecosystem and the reactivity of materials having H atoms, the hydrogen isotope exchange reaction(T-for-H exchange reaction) between 6-Chloronicotinic Acid(or 5,6-Dichloronicotinic Acid) and HTO vapor was observed at 50-70℃ in the gas-solid system. Applying the A"-McKay plot method to the data obtained in the reaction, the rate constants of the functional groups in each material were obtained. Comparing these constants, following four matters have been found in the T-for-H exchange reaction. (1)With regard to pyridine derivative, the reactivity of carboxyl groups depends on the number and position of chloro groups;(meta-position and para-position of chloro groups):(para-position of chloro groups and meta-position of hydrogen):(meta-position and para-position of hydrogen)=1.9:1.5:1.0. (2)The reactivity of the unknown nicotinate derivatives can be obtained by applying the Hammett plot obtained in this work. (3)Using the A"-McKay plot method, the reactivity of each functional group can be obtained nondestructively, quantitatively, and be analyzed without using any masking reagent. (4)The method used in this work may be useful to determine the reactivity of the functional groups in similar materials.
To explore the predictability of radiocaesium concentration in the mature peach fruits based on the radiocaesium concentration in the young superfluous fruits picked at the fruit thinning period, the change in the radiocaesium concentration as well as potassium(40K) in peach fruits associated with fruit growth was monitored during the second year after the accident of the nuclear power plant in Fukushima. Radiocaesium concentration was found to be highest in the fruit 15 days after the full bloom stage, followed by the gradual decrease before harvest. In addition, variation of radiocaesium and 40K concentration with time was shown to be different in leaves and fruits. Finally, the young fruits 60 days after the full bloom date and the ripe fruits were taken from 24 orchards in Fukushima to compare their radiocaesium levels. The predictability of radiocaesium concentration and some considerations for practical use are discussed.
The environmental behavior of radioactive nuclides released from the Fukushima Daiichi Nuclear Power Station(FDNPS) accident in eastern Japan was investigated. The radioactive pollution of environmental samples, including airborne dust, soil, sediment, fish, and other organisms was described. It was evaluated for environmental behavior and fate of the radioactive material from the spatial and temporal distribution of the radioactive nuclides. In Higashiosaka City about 600km away from FDNPS, it begins to detect the radioactive nuclides in the airborne dust from 25th March 2011. Radioactive fission products 95Zr-95Nb was detected on 18th April. The concentrations of 131I, 134Cs, and 137Cs in the soil collected from Fukushima City were 126000, 14000, and 14200Bq/kg on 19th March 2011 and 12800, 13200, and 13700Bq/kg on 26th March 2011, respectively. The concentrations of 131I, 134Cs, and 137Cs in the soil samples collected from March-June 2011 from study sites in metropolitan area and Kanto region ranged from nd to 91900, 59 to 16100, and 69 to 17600Bq/kg, respectively. (Concentrations of 131I were done decay correction to the value of 16th March) Radioactivities in fish samples collected from off FDNPS, Tokyo Bay, and Kejonuma Pond were measured. The radioactive contamination of forest ecosystem was also investigated. Two processes are involved in the radioactive contamination of the environment from the FDNPS accident. One is contamination by radioactive nuclides released from the hydrogen explosion. Leakage of contaminated cooling water to the ocean is in other important environmental pollution. We must continue carefully monitoring of radioactive nuclides in the environment.
Two spectroscopic methods using nuclear resonant scattering by synchrotron radiation, Synchrotron Mössbauer Spectroscopy and Nuclear Resonant Vibrational Spectroscopy(NRVS), have been intensively developed and utilized in recent years. Synchrotron Mössbauer Spectroscopy is suited for the research of the samples under extreme conditions such as at high pressure and at high temperature, because synchrotron radiation offers the small and highly collimated beam. It is also good for the surface and interface study of the thin film by the same reason. NRVS has been used to get the information of the phonon partial density of states of the specific isotopes, especialy for the research of the active center of the enzyme.
The dynamic behavior of low-temperature water confined in MCM-41(pore diameter 2.1nm) is investigated over a temperature range 180 - 298K by quasielastic neutron scattering and neutron spin-echo methods. The relaxation time of capillary condensed water with temperature follows the Vogel-Tamman-Fulcher equation above 222K, but shows the Arrhenius type behavior below 222K, i.e. there is a dynamical crossover at 222K. The relaxation time of monolayer adsorbed water shows only the Arrhenius type behavior. This dynamical crossover corresponds to a structural transition between high density water and low density water in confinement.