[en] The properties of the powder and the sintered body of ZrO₂-8m/oY₂O₃-Bi₂O₃ prepared by coprecipitation method were investigated. The crystalization temperatures of the powder were increased with increasing of amount of bismuth, and the agglomeration was developed by the increasing of calcination temperatures. The sinterability was increased with the amount of Bi₂O₃ added which caused liquid phase, and the deterioration of the thermal expansions and the electrical properties were happened. The electrical properties of 8YZB system were that the electrical conductivity was from 3 x 10^-3(Ω cm)^-1 and the oxygen ion transference number was from 0.75 to 0.92. (Author)

[en] The Eddy current generated by the moving normal spot on superconductor depends on the shape of pole, the velocity of moving magnet, and the magnetic flux density. The Eddy Current that is taking place in a moving normal spot in a superconductor has been investigated in some details. The structure of the eddy currnet and magnetic field in the normal region has been studied.(Author)

[en] This study is concerned with the separation method of total rare earth oxides in Xenotime by acid digest method. Thioacetamide was used as a carrier, tartaric acid was used as a masking agent and oxalic acid was used as a precipitant. So the effects of three acid digest methods, pH of the solution, digesting time,tartaric acid, oxalic acid and aging time were oberved. The results showed that the best acid digest method was sulfuric acid leaching and mixed acid digest method, and that pH of the solution was 2, digesting time was 4 hours, tartaric acid was 100 ml of 2% solution, oxalic acid was 8 gr. and aging time was 1 hour. Through this experiment, it was confirmed by X-ray diffractometer that the separated total rare earth oxides consisted of the Yttrium and the other rare earth elements : Gadolinium, Dysprosium, Erbium, Ytterbium and trace rare earth elements. The pure rare earth oxides being separated by this method were dried and ignited at 900 deg C (Author)

[en] Experimental investigation is made to study the dependence of performance characteristics of heat pipe on the types of wick shapes. Types of wick shapes adoped are open groove wick, screen wick, closed groove wick and no wick.(thermo-syphone). The dependence of heat pipe performance on the wick shape is turned out in the following order ; open groove wick, closed groove wick, screen wick and no wick. This shows that the heat transfer efficiency of heat pipe depends more upon the returning capacity of liquid from condenser to evaporator, implying that the wick which has low capillary pressure but good permeability is better than those which has higher capillary pressure. (Author)

[en] An investigation of Mo addition effect on the sinterability of 304L austenitic stainless steel powders was carried out by using the compacts of three different Mo contents (0, 2 and 5 wt%) and using diffusion couple of same stainless steel and Mo powders. The compacts of pure stainless steel powder showed conventional sintering process. And also, we found the diffusion (alloying) layer, 60μm, and porosity formation toward stainless steel compact in the vicinity of coupled zone by means of SEM and EDS analysis. The porosity of compacts to which Mo was added, was high compared with no Mo added compacts except early stage of sintering. But in compacts sinteed at 1200 deg C for 45 min, the abnormal increase of porosity could be understood by 'bridging' effect of alloying layer formed during sintering process. (Author)

[en] Fe-Ni martensitic alloys being available for base alloy of strength alloy steels were controlled to have three kinds of microstructure such as lath martensite, plate martensite and mixture of them, by adjusting Ms temperature due to addition of nickel. And then effect of the microstructure on damping capacity of the Fe-Ni binary system was studied. The damping capacities of the Fe-Ni martensitic alloys were increased with maximum surface strains, And the damping capacity of the lath martensite with substructure of dislocation was higher than that of the plate martensite having substructure of internal twin. From this result, it was concluded that the dislocation substructure has greater influence on the damping capacity than the substructure of internal twin in case of non-thermoelastic martensitic alloy. On the other hand, the damping capacity of austenite was higher than that of the martensite in Fe-31% Ni and Fe-33% Ni alloys. This was because the magneto-mechanical damping capacity of the former was higher than that of the latter. The damping capacity of mixed phases of the austenite and the martensite was decreased linearly with increasing martensite volume fraction. In other words, the damping capacities in Fe-Ni alloys were in good agreement with rule of mixture.(Author)