The causes of the decrease in electrical conductivity with aging in 11203-stabilized zirconia, an oxygen-ion conductor, were studied. This study was carried out using the dc four-probe technique for measuring electrical conductivity and the activation energy for the migration of oxygen ions. The results show that conductivity decreased with aging below certain temperatures in all specimens. Moreover, it was found that conductivity decreases significantly as the temperature decreases. Samples that were aged at relatively low temperatures exhibited a decrease in conductivity and an increase in activation energy. It was concluded that short range ordering of oxygen ion vacancies toward the zirconium to relax the anistropy of the lattice distortion is the cause of the decrease in electrical conductivity and the increase in activation energy. When aging was carried out at a relatively high temperature, fully stabilized zirconia showed no change in activation energy and only a slight increase in conductivity. This is because oxygen ion vacancies are in the disordered state and the cubic phase is the only phase at this temperature. Short range ordering of oxygen ion vacancies takes such a long time presumably because these oxygen ion vacancies are still able to move even after aging. This was explained using the concept of mean first passage time Infroduction Since Nernst reported Y203-doped Zr03 in 18991 and the

SUMMARYThe element free analyses of shell and spatial structures are conducted. The original element free Galerkin method proposed by Belytschko et al. is enhanced to analyse three-dimensional thin structures. By using the mapping technique the geometry of arbitrary curved surface is expanded in the two-dimensional space, and the bases of convected co-ordinate system are utilized for the expression of strain and stress components in the virtual work principle. Only nodal data are generated on this two-dimensional space and the convected co-ordinates are used in the moving least-squares interpolation method for the approximation of displacement "eld. For shell, the formulation allows transverse shear strain, therefore, it results in the Mindlin plate when the surface is #at and membrane state is negligible. In order to avoid shear and membrane locking, bi-cubic and quartic basis functions are adopted for the interpolation. For membrane structure, as geometrical sti!ness to support the structure cannot be negligible, geometrically non-linear analysis is essential and the total Lagrangian method is adopted for the formulation. Several numerical examples are demonstrated to show the validity of the proposed method and the satisfactory results are obtained in comparison to the theoretical or the "nite element results.

We demonstrate an aerial projection system for reconstructing 3D motion pictures based on holography. The system consists of an optical source, a spatial light modulator corresponding to a display and two parabolic mirrors. The spatial light modulator displays holograms calculated by computer and can reconstruct holographic motion pictures near the surface of the modulator. The two parabolic mirrors can project floating 3D images of the motion pictures formed by the spatial light modulator without mechanical scanning or rotating. In this demonstration, we used a phase-modulation-type spatial light modulator. The number of pixels and the pixel pitch of the modulator were 1,080 × 1,920 and 8.0 μm × 8.0 μm, respectively. The diameter, the height and the focal length of each parabolic mirror were 288 mm, 55 mm and 100 mm, respectively. We succeeded in aerially projecting 3D motion pictures of size ~2.5 mm3 by this system constructed by the modulator and mirrors. In addition, by applying a fast computational algorithm for holograms, we achieved hologram calculations at ~12 ms per hologram with 4 CPU cores.

A quantitative measurement method with FT-IR was proposed for a thermal degradation analysis of nitrile-butadiene rubber (NBR). An NBR film was prepared as a model sample on a barium fluoride (BaF2) crystal plate, which was subjected to a heat treatment. The absorbances of various functional groups were measured directly by FT-IR after thermal degradation at high temperatures. By measuring the absorbances, it was possible to readily determine quantitatively each of the functional groups after the degradation of NBR. By assuming that the NBR lifetime was the point at which the absorbance of a carbon-carbon double bond reaches 45% of that prior to thermal treatment, a method for predicting the lifetime of NBR heated below 150˚C was proposed, by using an Arrhenius plot of the heating time versus heating temperature.

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