Purification of the 3, 5-xylenol+2, 5-xylenol and the 2, 5-xylenol+naphthalene systems was attempted by normal freezing. They are simple eutectic-forming organic mixtures. Experimental conditions such as lowering rate of sample, diameter of a glass tube, temperature of cooling section, and stirring rate of liquid sample were examined. The experimental results showed that a good separation was achieved under the conditions of sufficiently small lowering rates with sufficient stirring of the liquid sample. The difference of the diameter of the glass tube and temperature of cooling section did not affect on separation efficiency. When xylenol was a main component, the crystal grew like dendrite. On the other hand, the crystal grew like grain when naphthalene was a main component. Best separation was observed for the system in which 2, 5-xylenol was a main component and naphthalene was contained as an impurity component. Furthermore, concentration profiles for impurity in the solid were correlated by a model of trapping of mother liquid with the effect of adsorption of impurity on solid surface.

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The vapour Pressures of PbS in the moltem Cu₂S-FeS-PbS system have been measured by means of the transportation method at 1150°C The activity of PbS exhibited nearly negative behavior and the data obtained was used to calculate the activities of other components and slight negative deviations of a_cu2s and a_Fes from Raoult's law were observed in the molten Cu₂S-FeS-PbS system.
The activities of Cu2S and FeS of Cu₂S-FeS melts were calculated by Darken's method extrapolated from Cu₂S-FeS-PbS system to Cu₂S-FeS system, and they showed negative deviation from ideality.
Furthermore, the distribution behavior of Pb between matte and slag was explained by thermodynamic analysis.

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Heat-treatment process is very important on sol-gel method. Because amorphous samples are crystallized by heat-treatment. Therefore, the heat-treatment process decides various properties of samples.
We measured TG-DTA, XRD and electrical properties for samples which were heat-treated under the conditions of various temperatures and atmospheres. And we investigated the effects of the heat-treatment conditions on the properties of samples.
As a result, it was found that crystallization of ZrO₂ doped with Y₂O₃ was advanced with increasing terminal temperature and oxygen concentration during heat-treatment process. On ZrO₂ thin films, it was found that the crystalline was false cubic under 700°C and changed to monoclinic above 800°C. On the other hand, on ZrO₂ doped with Y2O3 (4.4mol%), the thin films crystalline was cubic at 800°C. And these crystallization of ZrO₂ and YSZ were advanced with incresing heat-treatment temperature or with heat-treatment process with O₂ flowing. Especially, it was obtained that the crystallization of cube and O₂ ion conductivity was increaced with O₂ atomosphere of YSZ.

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Electrorheological fluid stably dispersing surfactant coated barium tianante and magnetic fluid dispersing surfactant coated magnetite have been mixed. This mixure (Magneto-electrorheological fluids) is that ultrafine barium titanate and magnetite (size=10nm) are stably dispersed in insulated oil. The magnetite particles make elongated agglomerates in the dirrection of magnetic field and barium titanate ones make agglomerates in the direction of electric field in the oil. The mixed fluid have been thinly sandwiched between transparent electrodes. This thin fluid film can penetrate visible ray under no electrric field and scatter visible ray under electric filed in the direction perpendicular to the plane of the thin film. Response time until scattering the visible ray by applying electric field depends on the fluid viscosity and decay time until penetrating it in the initial state can be shortened by not only Brownian motion but also applying magnetic field in the direction parallel to the thin film.

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Particle shape has been recognized as one of the important properties of the particle present in powders, composite materiales and so on.
In this paper, ball milling was carried out on spherical zinc particles to get flaky ones. The mill used was made of alumina with a diameter of 144mm and the inner length of 130mm. Its volume was about 2.1 liters. The balls charged were also alumina with a diameter of 20mm. The progress of flakiness of particles was evaluated by the size distributions, the specific surface area and the observation by SEM of flaky products.
The following results were obtained.
(1) The median diameter of flaky products increased with increase in the milling time.
(2) The increase of particle size-may arise for the flaking of particles in an early stage but the coalescence of particles in the later stage.
(3) It was presumed that the flaking of particles occurred during the specific surface area calculated by the flaking model of particles-measured by BET method relations have liniality.

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Electro ceramics showing interesting electrical functions can be produced by industrial ceramics manufacturing processes. The processes consist of, in general, the unit operations such as weighing, mixing, crushing, firing and so on. And electric functions of electro ceramics as final product depend on the combination of each unit operations. Microscopically, the electric function of final product can be considered to subject to the basic particle size of working material in each unit operation. Therefore, it is necessary to elucidate unit operation loop of ceramics manufacturing process.
n this paper, the change of basic particle size along the unit operation loop, that is, hierarchy change is fundamentally discussed, and the evaluation method of the hierarchy change is presented by applying to powder compact process of ceramics manufacturing processes. As a result, the hierarchy change of basic particle in powder compact process is qualitatively shown by using the evolution method presented.

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Kinetics of solid state reaction and grain growth behavior of BaTiO₃ -CaTiO₃ -SrTiO₃ ceramics have been studied. It is shown that the formations of BaTiO₃, CaTiO₃ and SrTiO₃ depend on the apparent particle size of the reactants. The solid state reaction is phase boundary controlled when the apparent particle size of the reactants is small. On the other hand, the formation is diffusion controlled when the apparent particle size of reactants is large. Grain growth of this system could be expressed by the equation Gⁿ=kt; and n=8.0 and Q=690kJmol^-1 (activation energy) were obtained under PO₂=10^-10Pa. The microstructure of this system can be controlled by oxygen partial pressure (PO₂) during firing. When PO₂≤10^-8Pa, microstructure of this system becomes fine and uniform.

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For obtaining higher productivity for the leaching of ilmenite ore by sulfuric acid, the effect of pre-oxidation and reduction was examined experimentally. In the leaching of reduced ilmenite ore, dissolution rate of reduced iron was extremely larger than that of undisposal ore, however, titanium was scarcely dissolved in the period of the iron-dissolution. As the results, enriched titanium dioxide was remained in the residue leached from ilmenite ore in a short time. This phenomenon enhanced under the conditions of higher leaching temperature, lower concentration of sulfuric acid, higher reduction degree and smaller particle size of ilmenite ore. On the basis of the result mentioned above, a process for recovery of titanium dioxide from leached residue was proposed as a new leaching technology of ilmenite ore.

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It is well known that the majority of viscous flow problems occuring in nature and in applications involves high Reynolds number and flow turbulence.In the oil hydraulic system, it may be required that the internal oil flow in the control elements is analyzed by considering the flow pattern in order to improve these dynamic characteristics.
In this paper, the boundary. element method is applied to field problems governed by Navier-Stokes equations, and in paticular, to internal flow in the hydraulic control valve.
Steady Couette flows were studied using the present solution procedure. The obtained simulation results were in excellent agreement with the exact solutions. The velocity profile in the hydraulic control valve was examined. The possibilies to design the high response control valve and to calculate the steady flow force of the valve were obtained.

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This paper describes a new method to prepare an amorphous Ni-P powder by non-electrolytic reduction. As a starting material a NiCl₂ solution was used and the pH of the solution was controlled by NaOH. Reduction was carried out by titration of NaPH₂0₂ and the reaction temperature was changed from 363K-333K. The reaction products were analyzed with SEM, thermal analysis and XRD. For the reaction a trace of oxygen played an important role. Under air little particle was formed, whereas after bubbling of nitrogen, spherical powders with 2μm diameter were obtained and they were confirmed as the amorphous state with crystalline temperature of about 618K.

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General remarks of diffusion phenomena in solid state ceramics during sintering are reviewed. Referring to Schottky disorder and Frenkel disorder, formation energy of possible disorder mechanisms of aluminum oxide is discussed. Intrinsic diffusion is defined as a function of temperature, while extrinsic diffusion is affected by foreign oxide additives/impurities. The difference between fixed valence impurity of Mg and variable valence of Fe in aluminum oxide is the one of the key factors for elucidating activation energy of defects formation. In addition, isotropic grain growth law is introduced in order to comprehend the quantitative treatment of solid state sintering.

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