Yukio Kawakubo

Vacuum Circuit Breaker Electrode Generating Multi-Pole Axial Magnetic Field and its Interruption Ability

Because the phase of the eddy currents in an electrode lags that of the main interruption current, a rather strong axial magnetic field remains at current zero in the space between a pair of electrodes when an interruption current is large. The authors analyzed the magnetic field on a circular conductor which was centered in a coil to stimulate an axial magnetic field type electrode. Because the authors found it difficult to eliminate the residual magnetic field from an electrode, they developed a new type electrode structure which does not generate a residual magnetic field at the center of an axis. An experimental vacuum interrupter equipped with this kind of electrode performed very well at testing voltages from 7.2 kV to 72 kV. Hitachi has applied this new type electrode in the development of a 7.2 kV 63 kA vacuum circuit breaker.

Rapid heat treatment for spin coated ITO films by electron plasma annealing method

Abstract A method of Electron Plasma Annealing (EPA) is developed. The EPA method allows a lower substrate temperature to be used in spin-coating-type ITO film fabrication. Using the EPA method is expected to have beneficial sample surface heating and plasma treatment effects. The ITO films which are treated in an N 2 gas atmosphere by EPA exhibit lower resistivity and higher transmittance than ITO films fabricated with a thermal treatment at 550 °C. The ITO films obtained by N 2 EPA treatment also show higher density and purity, although they have finer grain compared to the thermal annealing films. These structural features should be the reason for the good electrical and optical characteristics of ITO films.

Output power stabilization of a XeCl excimer laser by HCl gas injection

A laser output power control system which has an ability to realize high stability of the laser output power in long-term operation is proposed for high-power rare-gas halide excimer lasers. The system has a function of maintaining laser gas conditions, mainly the halogen gas concentration, constant against the gas degradation in the laser tube. As a result the laser output power is stabilized at near maximum available power. The system has been applied to a 20-W UV-preionozed XeCl excimer laser and the laser output power has been stabilized for 8 hours successfully with a fluctuation less than +/- 2% at 20 W.