The maximum entropy method (MEM) was applied to the free induction decay (FID) signal data by a Fourier transform NMR spectrometer to estimate super-resolved spectra. For 31P NMR spectra of the phosphate solution, the chemical shifts by the MEM agreed with those by FFT. For higher plant cells (mung bean root tips), the resolution of 31P NMR spectra by the MEM was more highly resolved than that by FFT. Moreover, the MEM estimation gave consistent cytoplasmic pH from Pi and G-6-P chemical shifts, but FFT did not. From the FID for one fifth of the usual accumulation time, we could also obtain intracellular pH accurately. Therefore, it is believed that the MEM will develop to be an important means in the 31P NMR study.
Thermally-stimulated currnt (TSC) in poly (p-phenylene vinylene) (PPV) and its doping effect were studied. TSC peak in undoped PPV is observed at around 60°C. The activation energy was evaluated as 0.5eV. In I2-doped PPV, two TSC peaks (P1, P2) were observed. The P1 peak moves to the low-temperature side upon increasing the I2 concentration. The P2 peak was observed in the same temperature range as the peak in undoped PPV. The activation energies were evaluated as 0.2 and 0.4eV for P1 and P2 peak, respectively, regardless of the amount of dopant. It is assumed that the P1 peak originates from electron traps formed by the effect of doped I2 molecules. Moreover, it is considered that the localized center of the peak for undoped PPV and the P2 peak for I2-doped PPV is due to defects originally existing in PPV.
A radiation dosimeter has been developed by observing the free radicals created in sucrose. The free radicals were observed by using the electron spin resonance (ESR) equipment of JES-PE-1X type. ESR absorption due to the free radical in sucrose appeared at the magnetic field between the third and fourth ESR ones of the standard Mn+2 sample. Hardly any fading of free radicals in sucrose was observable even two months after irradiation. Sucrose as a radiation dosimeter can linearly measure the dose from 4×10-2Gy to 105Gy. If the new model of the ESR equipment is used and ESR observation is carried out at lower temperatures such as liquid nitrogen or liquid helium temperature, the sucrose ESR dosimeter will be able to detect about 1mGy or less of the dose.