The changes in the gas permeability and permselectivity of natural zeolite disk by heat treatment were examined. The natural zeolite disks were fired for several hours at temperatures of 673 to 1273 K. The gas permeability and separation factor of the disks were measured by the gas permeation experiments with nitrogen-hydrogen gaseous mixture. The pore size distributions of the disks were evaluated by mercury porosimetry. The gas permeation experiments showed that gas permeability and separation factor simultaneously improved under a proper heat treatment condition. However, the measured mean pore diameters of the heat-treated samples was found to increase as the heat treatment temperature was increased. Such phenomenon could not be interpreted with considering conventional gas molecule transport mechanism through straight pores. Based on the observations, a qualitative model for pore structure change by neck growth due to sintering was proposed to account for the simultaneous improvement of the gas permeability and separation factor.

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V₂O₅ gels corresponding to the formula V₂O₅·nH²O with n=2.07, 0.5, and 0.2 have been prepared by the hydrolysis of VO (OC₂H₅) ₃, followed by washing and drying. After dehydration, V₂O₅ crystallizes at 310° to 400°C. V₂O₅ powders with striplike particles are produced after heating at 630°C. Well-densified V₂O₅ ceramics (97.7% of theoretical) have been fabricated by the combined use of hot pressing (630°C/2h/30MPa) and hot isostatic pressing (630°C/1h/196 MPa). The texture is of a plate structure, the grain being=30μm long and+6μm wide. Electrical conductivities have been measured in the temperature range of 25° to 600°C. Activation energies are determined to be 0.09 and 0.18 e V for initial and final stages, respectively.

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One of main problems with the Wavelet-Galerkin is the treatment of boundary conditions. It is sloved by our method which is referred to as Fictitious Boundary Approach. In this approach, a fictitious boundary is assumed to tackle the difficulty of treating boundary conditions. And an additional condition is also made in order to ensure the real solution. This method is adapted to all the three kinds of boundary conditions in the theory of differential equation. To support our method, an SH wave mode problem in a plate is solved, and its numeral result is compared with the exact solution. Although the Wavelet-Galerkin has very good features for solving differential equations, we find that it is still difficult to represent the infinite resonance solution after investigating the error convergence near the resonance point. And we emphasize the importance of selecting a proper scale j especially to represent the solution near the resonance.

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Effects of band structure and matrix element on the magnetic susceptibility defined as the Fourier transform of RKKY interaction are investigated accurately assuming the simple band model, and the validity of the free electron model is also examined. The following points are verified from the numerical calculations. When the Fermi surface has sections perpendicular to the vector q, in which q is an argument in the susceptibility, the strength of the Kohn anomaly is largely modified by the matrix element, which can be replaced by the values at the states on the Fermi surface causing the anomaly. When the Fermi surface has no sections perpendicular to q, the replacement cannot be allowed and their integration is important, and therefore it may be difficult to predict the matrix element effect. When the free electron Fermi sphere is completely contained in the Brillouin zone and is sufficiently away from a zone boundary, the free electron approximation is still rather good, although the effects of the Kohn anomalies and the matrix elements can be seen. But, when the sphere extends into other zones, since it is cut at the zone boundaries into some parts, the dispersion of the susceptibility becomes very much complicated by the presence of many Kohn anomalies, and can be also changed further drastically by the matrix element effect.

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The collection of ultrafine silica particles (23nm in diameter) and oilwater emulsion (500nm in diameter) from low concentrated suspensions were studied by using an ecomaterial (slag fibers) -collector bed system. The collec tion efficiency was highly dependent on the sol's pH and less on the specific surface area ratio between collector and ultrafine particles. The highest collec tion efficiency was attained at pH 4 for silica and at pH 3 for oil-water emulsion. The experimental results were partially interpreted by the total interac tion potential theory. In the case of the collection of ultrafine silica a second. mechanism regarding flocculation by the dissolved fraction of the SF comple mented the DLVO theory. In the case of the collection of oil-water emulsion effects regarding the deformable character of the oil drops as well as the hydrodynamic effects derived from the high molecular weight of the oil comple mented the DLVO theory.

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An approach to the synthesis of silicon carbide (SiC) ultrafine (u. f.) particles using silica (SiO₂) powders by high temperature flame was briefly introduced. Calculations including Gibbs free energy of different reaction systems showed the possibility of SiC formation. The SiO₂ u. f. particles (5-10nm) could be formed from the Si₂ powders (50-100μm) by high temperature CH₄-O₂ flame around 2500 K. β-SiC u. f. particles including reticular membrane could be synthesized by an electric furnace at about 2018 K through Si+CH₄, SiO+CH₄ and SiO₂+CH₄ reaction systems, respectively. The effects of H₂, CO, CO₂ and H₂O on the SiC percentage of synthesized u. f. particles were tested.

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Cyclodextrins modified with sodium anthranilate (1-β, 2-β and 1-α) have been synthesized as a sensing molecular for organic guests including terpenoids and bile acids. These host compounds show a pure monomer fluorescence with increasing or decreasing by accommodation of guest species. The extent of fluorescence variation with a guest is used to display the sensing factor (ΔI/I⁰) of these host molecules. Among thc host molecules, 1-β which is modified with bis sodium 2-aminobenzoate at primary hydroxy side of the β-cyclodextrin, shows the highest sensing factor. The molecularrecognition behavior of 1-β shows two ways depending on a guest molecule size; one way is both of the modification residues are coming into the cavity when larger guest such as bile acids were used and another way is the appended ones moving out of the cavity when a relative small guest such as terpenoids were used. Compounds 2-β, which is capped with amino benzene carboxylate on the primary hydroxy side of β-cyclodextrin and α-cyclodextrin modified with an anthranilate (1-α) hardly display sensing ability for bile acids, it is probably caused by the low mobility of the appended residue of 2-β and a smaller cavity size of 1-α.

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In order to clarify the hydrodynamic characteristics of a wing in a shear flow with arbitrary velocity distribution, an eigenvalue problem of Sturm-Leouville type holding along the span of the wing is numerically solved and the resulting numerical solution is matched to the analytical solution of the integral equation holding in a plane normal to the span.
This is an example of a “quasi-analytical method”.

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The studies on calcination have illustrated clear influence on the life time of multilayer ceramic chip capacitors with Ni electrodes by means of highly accelerated life test. Regarding the life time of the capacitors, the experimen tal results showed remarkable evidence of (1) effects of suitable amount of Fe and Mn additives, (2) homogeneous calcination with maintaining A/B≈a1.01 nonstoichiometry of ABO₃ perovskite structure, and (3) high temperature calcination after completion of binder burn out. By computer aided microstructural analysis, the distribution of constituent and impurity ele ments of the capacitors were found to be dependent on calcination tempera ture. The change of the lattice constant of ABO₃ at high temperatures and thermal behavior of ABO₃ are also discussed.

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