Analytical Electron Microscope Analysis of the Formation of BaO · 6Al2O3

The formation process of barium hexaaluminate (BaO 6Al₂O₃) from BaCO₃/γ-Al₂O₃ powders or hydrolyzed alkoxides was studied by analytical electron microscopy. Barium hexaaluminate is produced by a two-step solid-state reaction from BaCO₃ and Al₂O₃ via formation of BaO·Al₂O₃. Marked grain growth and inclusion of nonequilibrium phase were inevitable in this powder mixture process. However, in an alkoxide-derived precursor, homogeneous mixing of components is attained and hence the formation of BaO·6Al₂O₃ proceeds readily. Powders obtained by this latter route consisted of fine planar particles with a uniform size and retained a large surface area (20.2 m²/g) even after heating at 1300°C. Electron diffraction results implied that suppression of crystal growth along the c axis is the reason for the large surface area of BaO·6Al₂O₃.     

Performance of LANDSAT-5 TM data in land-cover classification†

An experimental analysis has been conducted on the performance of the new LANDSAT-5 Thematic Mapper (TM) data for detailed land-cover classification using a maximum-likelihood method. Data used is the TM test data of the Tokyo metropolitan area (path-107, row-035) of 4 November, 1984. Map-precision geometric correction is performed and TM data are resampled to 30 m pixel spacing. The experiment is designed to determine how well TM categories land-cover types in comparison with the Detailed Numerical Information digitally formatted data (Geographical Survey Institute of Japan, 10 m spatial accuracy), together with ground truth data in a representative test area. Classification accuracy for aggregated 12 categories within the test area is about 47 per cent with the application of the explicit filtering technique utilizing 3×3 neighbourhood operations. This increases to 70 per cent using a majority logic filter with a larger 5×5 neighbourhood function. Associated with the classification accuracy, effects of the mixed pixels are also investigated. The results show that the improved characteristics of TM aided the overall classification accuracy.     

Sensitivity analysis of stochastic dynamical systems

A new, efficient algorithm is developed for the sensitivity analysis of a general class of stochastic dynamical systems. The algorithm is based on an idea of the likelihood ratio method that utilizes a probability density information for the sensitivity analysis, and on the Fokker-Planck or Kolmogorov's forward equation for computing the evolution of probability densities. The ideas of stochastic sensitivity analysis and likelihood ratio method are presented and combined to derive the sensitivity of average values of the performance functional with respect to system parameters. The present algorithm avoids the time consuming Monte Carlo or stochasic simulations, and, instead, sensitivity gradients of the probability density function and performance functional are directly computed during single-run simulation.     

Proteolytic Degradation of Threadfin-Bream Meat Gel

The textural degradation of threadfin-bream meat gel accompanying the breakdown of the myosin heavy chain was caused not by a heat-stable alkaline proteinase (HAP) but by a newly found gel degradation-inducing factor (GIF). GIF as well as HAP was recovered in the sarcoplasmic fraction, but GIF was separated from HAP by gel filtration on Ultrogel AcA 34. This factor showed strong proteolytic activity against the myosin heavy chain at pH 7.0 in the presence of 2.5% NaCl.     

Electrical Properties of Superionic Conducting Glasses in the Pseudobinary System CuI-Cu2MoO4

Cu⁺-ion-conducting glasses were prepared in the pseudo-binary system CuI-Cu₂MoO₄. These glasses have high ionic conductivities at room temperature in the range 10⁻¹ to 10° S·m⁻¹, which are 10 to 20 times greater than those of the Ag⁺-ion-conducting glasses with the same iodide contents in the system AgI-Ag₂MoO₄. The conductivities increase with increasing CuI content. The increase in the conductivity can be explained in terms of a decrease in the activation energy for conduction. The electronic conductivity was measured by the Wagner polarization method and indicates that the transport number of Cu⁺ ions in those glasses is 0.9996 and larger.     

Variation of Noise and Magnetostriction Associated with Joint Types of Transformer Core

In order to study the acoustic noise generated by transformer cores, the impacts of the types of core joint and the number of laminations per layer on noise levels were investigated. In addition, localized magnetostrictions on transformer cores were measured with strain gages, and the differences caused by the types of core joint were investigated. The following were obtained as the results. The step‐lap configuration reduced noise levels in comparison with the conventional lap. An increase of the number of laminations per layer raised the noise levels. The differences occurred in the higher harmonic components than the fundamental component. There was a certain connection between localized magnetostriction and noise with respect to the types of core joint. The magnetostriction measured on a single sheet sample with sinusoidal excitation had less correlation with the localized magnetostriction measured on the core.     

Development of High‐Power Density Interleaved dc/dc Converter with SiC Devices

We developed an interleaved dc/dc converter with SiC devices. We applied full‐SiC modules including MOSFETs and SBDs to the interleaved dc/dc converter to achieve a high‐power density. An SiC has a high temperature resistance, which facilitates an improvement in high‐frequency drives. We achieved a high‐power density by utilizing this high temperature resistance. We also fabricated a prototype and tested it with loads up to 65 kW.     

Autoxidizing Process Interaction of Linoleic Acid with Casein

Autoxidized linoleic acid was classified to linoleic acid (LA), its hydroperoxide (LAHPO) and secondary autoxidation products (SP), and interactions of these products with casein were investigated. Casein was antioxidative to the autoxidation of LA. The products were readily bound to casein at 37°C within 1 hr in order of SP > LAHPO > LA. SP and LAHPO facilitated the access of fluorescent probes to casein and made casein insoluble. Casein was subsequently became undigestible during 1 day incubation with SP or after 2 days with LAHPO. Incubation with SP for 4 days or more caused casein to lose its amino acids and to polymerize.