Observations of high-field domains in GaxIn1 ? xSb Gunn diodes

The properties of high-field domains in GaxIn1-xSb Gunn diodes (0.4 < x < 0.82) have been studied by measuring the surface potential on the diodes. The domain velocities vary with the Ga composition x, 5.3?6.1×106 cm/s for0.8 > x > 0.55 and 10×106 cm/s for x = 0.4, but they are almost independent of the applied voltage, even if the electron concentration is increased by the impact ionisation in the domain at high applied voltages for the small-x samples.     

Contact resistance in liquid nitrogen

The resistances of Cu, stainless steel, brass, Al, Fe, Ag and Au contacts in liquid nitrogen were measured. The contact resistance in liquid nitrogen was higher than that in air varying from several times to one thousand times greater. The resistance was seen to decrease inversely with an increase of current, but, only the Au contact was very little influenced by cooling.     

Shape oscillation of bubbles in a row excited by ultrasonic vibration

Behaviors of bubble(s) exposed to an ultrasonic vibration are focused. Size of the bubbles interested in the present study is of O(1 mm) in diameter. The bubbles were injected through the micro syringe to the test fluid (water or water/surfactant mixture) filled in the rectangular tank. Ultrasonic vibration was irradiated to the bubble(s) after the detachment of the bubble from the tip of the syringe; thus the bubbles were exposed to the periodic oscillation in rising the test fluid. The authors clearly detect radial and shape oscillations under the large-amplitude vibration by use of high-speed camera. Preferable mode number of the shape oscillation, and the transition process from the radial to the shape oscillation are discussed.     

Retardation‐controlling color filter with two directly stacked retardation layers

Abstract— A polymerizable liquid crystal (PLC), the orientation of which can be frozen, is useful for making retardation layers. In this paper, a new color filter (CF) with retardation‐controlling layers made of PLC is reported. It has a positive A‐plate and a negative C‐plate, both directly stacked on a color‐filter layer. These two retardation layers exhibit good orientation ability, and function well as retarders, even when they are only 1/10 or less as thick as ordinary retardation films. The new CF also has excellent thermal stability. The change in retardation after heat treatment at 200°C for 30 min is around 5%, and there is no observable peeling. A prototype VA‐LCD made with our new CF provides good optical compensation, with the light leakage being extremely low in all azimuthal directions. This technology is very useful for making thin, highly reliable color filters for LCDs, even with other modes.     

Feasibility study on cellular network analysis with patterned cell culture microdevice

In order to realize cellular network analysis on a chip-based system, our group has been developing a patterned cell culture microdevice with pillars in an array for tapping cells into space surrounded by the pillars. The pillar structures has advantages to trap both adhesive and non-adhesive cells and to precisely control positions of cells and distances between cells for understanding effects of various cell patterns on functions of a cellular network such as cell proliferation, differentiation, and network formation. In this paper, HeLa cell cultivation with the patterned cell culture microdevice having a pillar array fabricated by dry film of thick negative photoresist SU-8 on a glass substrate was executed as a feasibility study on a cellular network analysis. The results revealed that the device performance was found to be enough to culture HeLa cells for more than 48 h. In addition, relative extensibility of blocks of multiple cells compared with single cells tapped on the device was observed. Thus, the patterned cell culture microdevice proposed here could be applicable to analysis of cellular functions.     

A new technique to measure the temperature of a rotating motor shaft

In the present study, a new technique has been developed for the measurement of the temperature of a motor shaft rotating at high speed. A radiation thermometer could be useful as one of the methods of measuring the surface temperature of said shaft. However, if the cross-sectional diameter of the motor shaft is small, it is necessary to closely approach the shaft rotating at high speed when measuring the temperature. The present paper reports the successful measurement of the local surface temperature and the temperature rise time of a motor shaft with a diameter of 10 mm diameter, rotating at high speed, by utilizing the potential of the melting points of different chemical reagents. The measurements were carried out at a distance of 1 m from the shaft, overcoming the difficulty in the use of a radiation thermometer.     

Improved Filtration Performance of Continuous Alumina-fiber-reinforced Mullite Composites for Hot-Gas Cleaning

The effect of filtration layer morphology on filtration performance at 673 K was investigated for continuous alumina-fiber-reinforced mullite composite filters that capture fly ash on their outer surfaces. Two types of filtration layers were prepared on the outer surfaces: a mono-layer consisting of mullite agglomerated particulates and a bi-layer, with mullite whiskers formed by a vapor-phase reaction and strongly adhered to the particulates exposed on the outer surfaces. For filters with mono-filtration layers, the filtration efficiency was improved slightly by increasing the filtration layer thickness. However, the maximum differential pressure increased during the filtration tests. Adhesion of whiskers to the outer surface decreased the maximum differential pressure to about one-third less than that with the mono-filtration layer. This low differential pressure remained constant throughout the duration of the test, with corresponding increases in filtration efficiency.