Analysis of electro‐optical properties of polymer‐stabilized OCB and the application to TFT‐LCDs

Abstract— A 9‐in. full‐color polymer‐stabilized OCB TFT‐LCD with stable bend alignment in the absence of an electric field was developed. The condition of the polymer stabilization, the characteristics of UV‐curable monomers, and their influence on the configurations of the polymer network in the cell were studied. Possible models of the configuration were proposed and their relationship to the electro‐optical properties was analyzed using a novel simulation method considering the distribution of anchoring effects from both alignment surfaces and the polymer network. It was suggested that a good performance such as high contrast ratio and fast response could be expected in the polymer network originating from newly developed monomers composed of multifunctional LC acrylates due to a relatively weak‐anchoring effect and presumably its localization near the alignment surfaces. By using the newly developed monomers under the optimized polymer‐stabilizing process, a high contrast ratio of 250:1 and fast response nearly equal to that of a conventional OCB cell were achieved.     

Survey of actual viewing conditions at home and appropriate luminance of LCD‐TV screens

Abstract— To understand actual viewing conditions at home is important for TV design. And the preferred luminance level of LCD TVs under actual viewing conditions is also important in order to obtain both good picture quality and low power consumption. The actual viewing conditions of households and the preferred luminance levels was investigated. In a field test of 83 households, the display luminance, screen illuminance, and viewing locations were measured on site. In laboratory experiments, young and elderly subjects adjusted the luminance of an LCD‐TV screen to their preferred levels under different screen illuminance levels, angular screen sizes, and average luminance levels (ALL) of the images. As a result, two equations, which represent the preferred luminance level of LCD‐TV screens corresponding to different viewing conditions for young and elderly subjects were obtained. When the ALL of the images was 25% and the screen illuminance and angular screen size were set at 100 lx and 20°, respectively, the preferred luminance was 1 60 cd/m² for the young subjects and 248 cd/m² for the elderly subjects. By using the setting of the preferred luminance of an LCD TV under actual viewing conditions, it is possible to conserve energy consumption.     

Coefficients for equilibrium partition of a third element between solid and liquid in iron-carbon base ternary alloys and their relation to graphitization during iron-carbon eutectic solidification

During iron-carbon eutectic solidification, the coefficients for partition of a third element between the eutectic liquid and its solid were evaluated thermodynamically. The coefficientk _M ^A/L for the equilibrium partition of the third element (M) between austenite and liquid iron largely depended on the interaction between carbon and the third element and a simplified method for the evaluation ofk _M ^A/L was introduced. The coefficients,K ^S andK ^M, for the partition of the element between the eutectic liquid and its solid in the stable and metastable eutectic solidification, respectively, were also calculated fromk _M ^A/L and the coefficientk _M ^C/A for the equilibrium partition of the element between cementite and austenite. It was indicated by the thermodynamics of the free energy for the co-existing phases that the effect of a third element on graphitization occurring during eutectic solidification was related quantitatively to the value of K which was represented byK ^S-K ^M. The effect of a third element on the difference between the stable and metastable eutectic temperatures and on the carbon activity of liquid iron was closely related to K or the equilibrium partition coefficient,k _M ^C/A .     

Concrete with Highly Active Rice Husk Ash

The overall aim was to investtgate the effect of highly active husk ash (RHA) produced by an industrial furnace on some properties of concrete. The strength, pore volume and pore distribution of concrete and the Ca(OH)2 content in concrete were investigated by JIS A 1108 ( Method of test for compressive strength of concrete), a mercury instrument porosimeter, and the thermogravimetric analysis, respectively. The results show that, with RHA replacement of cement , the compressive strength of concrete is increased evidently;the average pore radius of concrete is greatly decreased, especially the portion of the pores greater than 20nm in radius is decreased while the amount, of smaller pores is increased, and the more the RHA replacement, the less the amount of Ca(OH)2 in concrete. The latter two results are the main reasons for the strength enhancement of concrete.     

Predicting the Life Span of Dies Used for Soft Magnetic Core Motors

This paper describes a method of predicting the life span of the dies used in motor manufacture from soft magnetic composites (SMCs). In the present study, a clawtooth motor was used. The method involves performing a stress analysis of a die followed by fatigue testing of test pieces. In the analysis, the SMC was assumed to be in powder form and its yield function was derived by a simple method. In addition to the analysis, we describe a simpler and more effective method in which the properties of the SMC are treated as boundary conditions. In the fatigue tests, we used test pieces that simulated the shape and construction material of the die. To predict the life span of the die, we evaluate the SN diagram, which represents the relationship between the maximum stress and fatigue life with respect to the stress generated in the die. The life expectancy of a new die, which is about 100 cycles of use, is found to agree substantially with its actual life. Furthermore, we explain how to extend the life span of a die to the targeted life span, namely, more than 200,000 cycles of use, by changing its shape to reduce stress.     

Development of Sensor and Control Systems of a Wearable Robot to Walk on a Step

The goal of our study is to develop a system for walking on a step using a wearable robot. Our system consists of (1) sensing of a step from the movement of the walker, (2) detection of the foot placement state related to the step, and (3) generation of gait patterns of climbing and stepping down for the step. In the generation of gait patterns for the step, toe trajectories are generated according to the height of the step to avoid collision of the swinging leg with the step. The hip trajectory is generated by an optimization technique that minimizes the sum of the joint angular jerk of the robot subject to constraints on the hip position and the velocity at toe liftoff. Each joint angle trajectory is calculated from the generated trajectories by means of inverse kinematic equations. We investigated the feasibility of the proposed sensor and control systems for two steps with different heights.     

Surface Analysis of Cr2O3‐, CoO‐, and Al2O3‐Doped Iron–Phosphate Glasses at High Temperature

Surface structures of iron–phosphate glasses were examined using X‐ray photoelectron spectroscopy (XPS). Cr₂O₃, CoO, and Al₂O₃ were introduced to the glass by the replacement of a part of Fe₂O₃, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC‐1 test. In situ high‐temperature and room‐temperature XPS measurements were conducted on the polished sample surfaces and also those after 1‐week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron–phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition‐metal ions.