Graphite formation on Ni film by chemical vapor deposition

Thin film formation of graphite by chemical vapor deposition using 2-methyl-1,2′-naphthyl ketone as a starting material was carried out on Ni film substrates. On Ni films directly deposited on quartz glass, the graphite films were obtained when the Ni film thickness was above 1 000 Å and above 5 000 Å at 700 °C and 1 000 °C, respectively. Depositions on thinner Ni film substrates comprise amorphous carbon (a-C) or graphite tubes which was owing to the thermal coagulation of the Ni film into droplets. On the other hand, graphite film was obtained on the Ni film with thickness 10 Å when a-C was inserted between the Ni film and the quartz glass. The coagulation of the Ni film is considered to be avoided by inserting a-C layer.     

Effects of surrounding brightness on visual search for safety colors

The present article reports the investigation of the effects of surrounding brightness on a visual search for three safety colors: red, orange, and yellow. Images of visual stimuli consisting of an array of colored circles placed on a large visual field (a visual angle of 40°) were displayed on an 80‐in. screen with a DLP projector. Experiment I examined the search efficiency under three levels of background luminance that were equivalent to the three target luminances. The results showed that the search efficiency for the orange target decreased as the number of distractors increased, under each of the background luminance levels, whereas the efficiency scarcely decreased for the red and yellow targets. Although a reduction in background luminance increased the search efficiency for the orange target, it is suggested that the effect of background luminance is smaller than the effect of the target color in search efficiency. Experiment II examined the search efficiency under three conditions of low levels of incident illuminance, which were matched with a linear regression to the luminance of color chips of safety colors measured twilight conditions. The results showed that the search efficiency for the orange target decreased as the number of distractors increased under each of the different illuminance conditions, whereas the efficiency scarcely decreased for red and yellow targets. Furthermore, as illuminance decreased, the search time for the orange target was more greatly impacted than for red or yellow. These results imply that the recognition of orange tends to be influenced by the surrounding brightness. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 400–409, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20152     

Improved ADPCM voice signal transmission employing click-noisedetection scheme for TDMA-TDD personal communication systems

In personal communication systems, better voice quality and lower terminal price are essential requirements, and adaptive differential pulse-code modulation (ADPCM) codecs are one of the voice codec candidates that have good voice quality and reasonable cost. However, in slow fading environments, burst errors induce click noise in ADPCM voice signal transmission. This paper proposes a novel error-concealment scheme to improve the ADPCM voice signal transmission quality of time division multiple access time division duplex (TDMA-TDD) personal communication systems in slow fading environments. The proposed scheme employs an improved error-detection technique with PCM differential detection and overflow detection coupled with a cyclic redundancy check (CRC) code. To compensate for residual click noise, an expanded CRC error-detection signal is used. Erroneous PCM signals are adaptively suppressed according to the click-noise detection information. Hardware simulation results show that these techniques significantly improve ADPCM voice signal transmission quality by 0.5 points and 1.0 compared to that of the conventional ADPCM muting scheme and no processing, respectively, with the mean opinion scoring (MOS) test in the slow fading environments typical of personal communication systems     

Age-related accumulation of phosphatidylcholine hydroperoxide in cultured human diploid cells and its prevention by α-tocopherol

The levels of phosphatidylcholine hydroperoxide in serially cultured human fetal diploid fibroblasts at various population doubling levels were determined by high-performance liquid chromatography combined with chemiluminescence detections. This methodology utilizes a mixture of cytochromec and luminol as post-column hydroperoxide group specific luminescent reagents. The cellular hydroperoxide content increased with age from 0.34 to 27.72 pmol/10⁶ cells. At the end of the cells'in vitro lifespan (51st population doubling level), the hydroperoxide content per 10⁶ cells reached about 80 times the level found in cells of the 20th population doubling level. Supplementation of exogenous α-tocopherol to the culture medium prevented hydroperoxide accumulation, but did not extent the lifespanin vitro. The results indicate that substantial intracellular phospholipid hydroperoxide accumulation occurred in the course of aging of human fetal liploid fibroblasts.     

Interfacial Reactions between Sapphire and Silver—Copper—Titanium Thin Film Filler Metal

Wetting and brazing studies of sputtering-deposited, submicrometer thin film filler metal in an Ag—Cu—Ti/Al₂O₃ system were performed. The interfacial reaction layer between the filler metal and Al₂O₃ was investigated. It is possible to make a brazing joint even with a reaction layer of less than 100 nm thickness. Different types of interfacial reaction layers were observed when the Ti content in the filler metal was varied. The Cu—Ti—O system compounds were observed in the samples with high wetting capabilities, but not in the sample with low wetting characteristics. It was found that these compounds are substances that promote effective brazing.     

Polymerization of methyl methacrylate by tri-n-butylborane in the presence of amino acid esters

The polymerization of methyl methacrylate by tri-n-butylborane in the presence of amino acid esters was investigated. The binary systems of tri-n-butylborane and amino esters were found to be more effective for initiating the polymerization than tri-n-butylborane alone. Co-catalytic effects of amino acid esters were in the order: tyrosinate > glutamate > aspartate ? phenyl alaninate > serinate > glycinate. The rate of polymerization in a mixture of dimethylsulphoxide and toluene was proportional to the square root of the concentration of the initiator system, to the monomer concentration, and to the concentration of dimethylsulphoxide in the solvent. The overall energy of activation was estimated to be 4.6 kcal/mol for the tri-n-butylborane/methyl tyrosinate system. Copolymerization curves gave a typical free-radical character.     

LC GRIN lens mode with wide viewing angle for rotatable 2D/3D tablet

To widen the vertical and horizontal angular ranges where the lens performs well, the off‐axis performance of a liquid crystal gradient index (LC GRIN) lens is analyzed by the combined simulation system of an LC director simulator and a ray‐tracing simulator. We found that the angular difference between an LC alignment direction and an electrode array direction of the LC GRIN lens is one of significant parameters, and detailed conditions of structure are established. The measurement result shows that the developed structure reduces the degradation ratio in a luminance profile from 61% to 3.2%. We have applied a user tracking system for the rotatable 3D display, equipped with a detection of a panel orientation and a face position. As a result, we have developed a rotatable 2D/3D tablet whose 3D viewing azimuth angle is over 30° in both landscape and portrait orientations.     

Implicit Formulation for SPH‐based Viscous Fluids

We propose a stable and efficient particle‐based method for simulating highly viscous fluids that can generate coiling and buckling phenomena and handle variable viscosity. In contrast to previous methods that use explicit integration, our method uses an implicit formulation to improve the robustness of viscosity integration, therefore enabling use of larger time steps and higher viscosities. We use Smoothed Particle Hydrodynamics to solve the full form of viscosity, constructing a sparse linear system with a symmetric positive definite matrix, while exploiting the variational principle that automatically enforces the boundary condition on free surfaces. We also propose a new method for extracting coefficients of the matrix contributed by second‐ring neighbor particles to efficiently solve the linear system using a conjugate gradient solver. Several examples demonstrate the robustness and efficiency of our implicit formulation over previous methods and illustrate the versatility of our method.     

Fast Particle‐based Visual Simulation of Ice Melting

The visual simulation of natural phenomena has been widely studied. Although several methods have been proposed to simulate melting, the flows of meltwater drops on the surfaces of objects are not taken into account. In this paper, we propose a particle‐based method for the simulation of the melting and freezing of ice objects and the interactions between ice and fluids. To simulate the flow of meltwater on ice and the formation of water droplets, a simple interfacial tension is proposed, which can be easily incorporated into common particle‐based simulation methods such as Smoothed Particle Hydrodynamics. The computations of heat transfer, the phase transition between ice and water, the interactions between ice and fluids, and the separation of ice due to melting are further accelerated by implementing our method using CUDA. We demonstrate our simulation and rendering method for depicting melting ice at interactive frame‐rates.