3-D analysis of functional instabilities of the ankle using digital still cameras

A technique to analyze the functional instability of an ankle is proposed. The technique is based on measurements using two digital still cameras. We carried out several experiments using this technique. Subjects are requested to stand on an experimental table whose angle of inclination is adjusted. By comparing the postures of both feet, we could tell that the subjects had experienced an ankle sprain and had functional instabilities in their ankles.This work was presented in part at the 8th International Symposium on Artificial Life and Robotics, Oita, Japan, January 24–26, 2003     

Present Status of EUV Interferometer Development at the Research Center for Soft X-ray Microscopy

A new interferometer for extreme ultraviolet (EUV) radiation with a laser produced plasma (LPP) laboratory source is under construction. The LPP source is operated with a Sn solid rod target on which pulsed YAG laser is focused to produce high temperature plasma emitting EUV radiation. The source is equipped with a newly designed debris stopper protecting a condenser multilayer mirror from the particle debris of the target. The condenser mirror focuses the light onto an EUV beam - splitter to form transmitted and reflected paths for producing interference fringes of a sharing type. The optical configuration is of a common path based on a triangular path type with a focusing at the beam- splitter, which is enabled to produce fringes by a low coherence radiation with a standard optical quality beam - splitter. The fringes are recorded by an imaging plate with pixels as small as 25μm. The dynamic range of linearity in detection of the EUV light was found to be more than 10^4 with sensitivity of 10^4 photo ns/pixel, enough for the purpose of interferogram recording possibly with one laser shot.     

Preparation and etching processing of planar thin film of Pr3+-doped fluorozirconate glass

Planar thin-films of a 60ZrF₄ · 35BaF₂ · 5PrF₃ composition were successfully prepared from Zr(hfa)₄, Ba(hfa)₂(tg), Pr(fod)₃ and NF₃ by an electron cyclotron resonance plasma-enhanced chemical vapor deposition technique. The films obtained were colorless and amorphous. As etching processing of the prepared thin-film, dry etching was performed using Ar, CF₄, SF₆, Cl₂ and Cl₂-BCl₃ gases. The Ar etching in which no reactive ion-etching is anticipated exhibited the fastest etching rate. Wet etching was also performed using a ZrOCl₂-HCl etching solution. The etching rate was extremely fast compared with those of dry etching. In this etching, however, undesirable side-etching occurred. At the present stage, therefore, the most preferable etching processing is dry etching by an Ar gas.     

Design and development of optical fiber joining techniques forefficient construction of aerial distribution cable systems

Two new optical fiber joining techniques have been developed for aerial distribution cables. One employs a compact mass-fusion splicer and the other involves a small mechanical splice. This paper describes their design and performance. These techniques are excellent for use in aerial sites and enable aerial distribution cable systems to be constructed efficiently. They will be useful for the economical construction of optical access networks for fiber-to-the-home     

Biofilm Spreading by the Adhesin-Dependent Gliding Motility of Flavobacterium johnsoniae. 1. Internal Structure of the Biofilm

The Gram-negative bacterium Flavobacterium johnsoniae employs gliding motility to move rapidly over solid surfaces. Gliding involves the movement of the adhesin SprB along the cell surface. F. johnsoniae spreads on nutrient-poor 1% agar-PY2, forming a thin film-like colony. We used electron microscopy and time-lapse fluorescence microscopy to investigate the structure of colonies formed by wild-type (WT) F. johnsoniae and by the sprB mutant (ΔsprB). In both cases, the bacteria were buried in the extracellular polymeric matrix (EPM) covering the top of the colony. In the spreading WT colonies, the EPM included a thick fiber framework and vesicles, revealing the formation of a biofilm, which is probably required for the spreading movement. Specific paths that were followed by bacterial clusters were observed at the leading edge of colonies, and abundant vesicle secretion and subsequent matrix formation were suggested. EPM-free channels were formed in upward biofilm protrusions, probably for cell migration. In the nonspreading ΔsprB colonies, cells were tightly packed in layers and the intercellular space was occupied by less matrix, indicating immature biofilm. This result suggests that SprB is not necessary for biofilm formation. We conclude that F. johnsoniae cells use gliding motility to spread and maturate biofilms.     

Temperature distribution in nano-devices under a strong magnetic field

The thermoelectric and thermomagnetic phenomena of two-dimensional electron gases at low temperatures are numerically examined using the finite-difference method. The temperature and the voltage are calculated from transport equations describing thermoelectric and thermomagnetic effects. The results demonstrate that a magnetic field distorts equipotential lines and generates an uneven distribution of the temperature, which can cause inhomogeneous heating of experimental systems. In particular, a part of the system is found to be colder than the temperature of the heat baths.     

Comparison of hydrogen isotope retention and irradiation damage behaviors in tungsten and SS-316 with simultaneous C+–D2+ implantation

Behaviors of hydrogen isotope retention and damages in tungsten and SS-316 with simultaneous C⁺–D₂⁺ implantation were compared to those with only D₂⁺ implantation using X-ray photoelectron spectroscopy (XPS), Thermal desorption spectroscopy (TDS), glow discharge-optical emission spectroscopy (GD-OES) and Transmission electron microscopy (TEM).The total D retention for SS-316 with only D₂⁺ implantation was about 45% as large as that for tungsten. The D retention for simultaneous C⁺–D₂⁺ implanted tungsten and SS-316 clearly increased as a factor of 1.7, which is almost the same among these samples. The density of dislocation loops was enhanced by the simultaneous C⁺–D₂⁺ implantation, indicating the D trapping site would be produced by C⁺ implantation. As for the D desorption temperature, small shift toward lower temperature side was found for SS-316 compared to tungsten, indicating the D trapping energy by dislocation loops and grain boundary for SS-316 is lower than that for tungsten.     

Interactions of supported nickel and nickel oxide catalysts with methane and steam at high temperatures

The catalytic performance of cermets made of 10% nickel or nickel oxide supported on YSZ (yttria-stabilized zirconia) for chemical looping combustion (CLC) and steam reforming (SR) of methane at 700 °C is investigated. Steam reforming of methane over the reduced catalyst resulted in a syngas containing more than 70% hydrogen and about 15% carbon monoxide. Chemical looping combustion of methane with insufficient lattice oxygen could potentially lead to 40–65% hydrogen rich gas products. Prolonged induction period (e.g. 30–80 min) in reduction of nickel oxide by methane has been observed in the presence of steam. The span of induction period increases by increasing steam partial pressure. It is hypothesized that the delayed reduction of nickel oxide is related to the retarding effect of steam on autocatalytic reactions of methane and hydrogen with lattice oxygen of nickel oxide and the subsequent reforming reactions.