Incubation period involved in the photo-induced phase transition has been studied by monitoring electron paramagnetic resonance signal. The incubation periods sub-linearly depend on the irradiating light power in higher power region. [Fe II (2-pic)3]Cl2EtOH (Fe-pic) exhibits the photo-induced phase transition (PIPT) from a diamagnetic phase to a paramagnetic phase at low temperature. In the PIPT, cooperative intersystem crossing mediated by spin lattice interaction play a key role 1) . Electron paramagnetic resonance (EPR) spectroscopy is one of the most powerful tools to study local structure surrounding a localized spin. In this study, dynamics of the local structural change in PIPT has been monitored by ESR signals of doped Co 2+ ions.
LHe-free MRI (HTS-MRI) magnets fabricated by REBCO tape or BSCCO tape superconductors are expected due to the high-priced LHe. However, HTS-MRI magnet has some problems: the stability of the magnetic field by use of a power supply in a driving mode, and a screening current, for producing a high stability magnet field, both temporally and spatially, necessary for MRI imaging. One solution for these problems is an active magnetic field stability control by use of a power supply instead of the persistent current operation. In this paper, we measured and evaluated the magnetic field stability, using commercial 3T-LTS-MRI magnet in the power supply driving mode with the highly stabilized power supply.
We investigated the resonant Raman scattering of the spin-crossover complex, [ Fe(2-pic) 3 ]Cl 3 EtOH , with varying the temperature and calarified for the first time that the photoinduced phase is completely different state from the thermally-induced phase. In the photoinduced phase we observed splits of Raman lines and a number of additional lines which are not observed in the high- and te low-temperature phase. These splits and appearances strongly indicate that a symmetry lowering should take place in the photoinduced phase. We imagined that the symmetry lowering is induced by the Jahn-Teller effect in the photo-excited state of the low-temperature phase.
Superconducting Fault Current Limiters (SFCLs) are expected to be installed in the power system for improving their reliability and stability. The three-phase transformer type coaxial SFCL with rewound structure have been proposed and designed in the past. Due to the rewound structure, internal magnetic field of an SFCL is cancelled and each phase of the SFCL can work independently without interference with the other coaxial phases. This paper describes current limiting performance and recovery characteristics in Recovery Under Load (RUL) operation of the proposed SFCL. The operation tests of the SFCL under load were carried out on a lab-scale model power system (one generator, double-circuit transmission line, and infinite bus system). In this system, faults occurred on one line. The SFCL was installed in the generator terminal in series and the generator continued to supply power to another line through the SFCL in fault sequence so the SFCL operated in RUL. It was confirmed that the SFCL limited the fault current from approximately 600 to 250 A, reduced the burden of the generator, and successfully recovered to superconducting state.
Applications of insulated metal substrates (IMS) for high-density and high-power mounting are rapidly extending with the miniaturization of electronic devices. The recent progress in insulation reliability and thermal conductivity of IMS has been making applications as substitutes for alumina DBC substrates possible. However, customers and/or potential customers are not satisfied with performance of conventional IMS for high-powered applications and an improved IMS equipping higher thermal conductive insulating layers is desired to widen the applications for high-powered devices. The influence of materials of which the IMS consists, i.e. base metals, insulating layers and copper conductors, were analyzed theoretically using FEM, and experimental data measured with a temperature distribution measuring instrument "Thermoviewer" were compared with the analytical data. The influence of the materials have been clarified through the analysis. In addition, an alumina DBC substrate and "GPS", which is a special IMS developed newly for large-current and high-powered devices, were also investigated comparatively by simulation and experiments.
To design a high performance IMS and extend its applications, the influences of materials, which IMS consists of, i.e., base metal boards and copper conductor thickness ,were analyzed theoretically using FEM. In addition, shock reliability of an alumina substrate and IMS, was examined and compared analytically and experimentally, too. The influences of the materials have been cladled through the analysis and the data were compared with experimental results. Liquid phase thermal shock tester was used for the experimental data and it was found that the analytical results and experimental data tend to be identical. 1. Intraductions
