Stabilization of Power Supply for the Shinkansen with Power Converters

In the Tokaido Shinkansen, rolling stock types have been unified as an inverter controlled type, which was introduced after Series 300. As a result, the input power factor of the main converter used in the rolling stock has been controlled to 1. In accordance with this change, the role of reactive compensation of static var compensators (SVC) has shifted from the load power of trains to the power consumed by the reactance in the electrical power system. Therefore, when taking into consideration the aging of power converters, it is time to reassess their layout and the configuration for the future of the Tokaido Shinkansen. We reassessed the equipment configuration, capacity, and layout of power converters and verified the impact on the stabilization of the power supply when introducing self‐commutated power converters.     

Fine structure and development of the collar enamel in gars, , Actinopterygii

The fine structure of collar enamel and the cells constituting the enamel organ during amelogenesis in Lepisosteus oculatus was observed by light, scanning electron and transmission electron microscopy. In the enamel, slender crystals were arranged perpendicular to the surface and the stripes that were parallel to the surface were observed, suggesting that the enamel in Lepisosteus shares common morphological features with that in sarcopterygian fish and amphibians. Ameloblasts containing developed Golgi apparatus, rough endoplasmic reticulum (rER) and secretory granules were found in the secretory stage. In the maturation stage, a ruffled border was not seen at the distal end of the ameloblasts, while many mitochondria and lysosome-like granules were obvious in the distal cytoplasm. The enamel organ consisted of the outer dental epithelial cells, stratum reticulum cells and ameloblasts, but there was no stratum intermedium. It is likely that the ameloblasts have less absorptive function in comparison with the inner dental epithelial cells facing cap enameloid.