In this report, we deal with a new type ceramics emitter which is composed of a silicon edge and a silicon carbide ceramics rod. The electrical, mechanical, and chemical characteristics at the interface between silicon and silicon carbide ceramics were investigated. These characteristics had no problem for practical use as an emitter. The discharge tests were carried out for the ceramics emitter, the tungsten emitter, and the titanium emitter with A.C. 7000V ionizer for 100hrs. After the discharge tests, these emitters were observed by a scanning electron microscope. The tungsten emitter showed a remarkable degradation. The titanium emitter changed into a crater like surface. However, the ceramics emitter did not show any change on the surface condition. The smallest curvature emitter generated the highest density of ions, and showed a remarkable degradation.
Winter precipitations were collected at Mt. Zaoh (the altitude 1650m above sea level, located in the northern part of Mainland Japan), over which westerly winds predominate during the season. The chemical composition of the precipitations was analyzed to examine the incorporation of soil particles coming from the Asian Continent; the results for the soluble components are reported. When so-called “KOSA” phenomenon (transport of the continental soil particles to Japan) took place, the concentrations of non-sea-salt (nss)-Ca2+ and Si, which are two major constituents of the soil particles, significantly increased in the precipitations. However, the ratio [nss-Ca2+]/[Si] remained much the same throughout the KOSA and the non-KOSA periods. This observation is consistent with the report of Iwasaka et al. that the continental soil particles were frequently transported to Japan even when the KOSA phenomenon was not apparent on the ground. On the other hand, the concentration of nss-SO42- also increased in the KOSA period, bot not in proportion to the Si concentration. From this result it was inferred that a part of nss-SO42- was not an inherent constituent of the particles but it became attached to the particles after they were blown up.
Three types of coal fly ash, one from a commercial coal fired power plant (sample A), one from a coal-heavy oil mixed fired model power plant furnace (Sample B) and one from a bench scale industrial furnace (Sample C), were fractionated into fractions in the range of > 149 - < 5 μm and < 1.6- > 3.2g/cm3 through sieving supersonically in methanol medium and with heavy liquid separation. From these fractions, carbon and sulfur were determined simultaneously with an oxygen combustion-infrared determination technique. Carbon enrichment was observed around the fractions of 149-45 μm and 1.6-2.4 g/cm3 in all three samples, while sulfur enrichment was obvious in the heavier and finer fractions in two power plant coal fly ash (Sample A and Sample B) and in an industrial furnace coal fly ash. The enrichment of sulfur was in the same fraction of carbon enrichment.