Narrow and Standard Gauge Lines Operations

This article illustrates a novel design of traction power converter and the specified control strategy of traction equipment of the GCT. We also introduce the test results to verify the basic function of the propulsion system and refer to the operating results in the gauge changing section to verify the control strategy.     

Convergent-beam and small-area-parallel-beam electron diffraction of icosahedral quasicrystals of a melt-quenched Al-Mn alloy

Intensity distribution in convergent-beam electron diffraction (CBED) patterns obtained from icosahedral quasicrystas of a melt-quenched Al-Mn alloy reveal that the quasicrystals do not have fivefold, threefold and twofold rotation axes and have no inversion center, although ordinary diffraction patterns obtained thus far showed these rotation symmetries. CBED patterns taken from specimen areas of about 3 nm in diameter show a deviation in geometry in spot positions from the fivefold rotation symmetry. Ring patterns due to higher-order Laue zone reflections are not observed in CBED patterns. Kikuchi bands are composed of two sub-bands in the five equivalent directions, and each band has a different intensity profile. Parallel-beam (3 × 10^-5 rad) electron diffraction patterns obtained from specimen areas less than 100 nm in diameter also show a deviation from the fivefold symmetry in spot positions and make clear that each Bragg reflection consists of many fine spots which show no fivefold symmetry. It is proven experimentally that all the observed reflections occur already in the approximation of kinematical diffraction, although their intensities may be modified by dynamical diffraction effect.     

Development and calibration of a karman vortex probe for measurement of molten-steel velocities

A velocimeter called the Karman vortex probe was developed to measure the velocity of molten-steel flow near the meniscus in continuous-casting molds. The measurement principle of this probe is based on a linear relationship between molten-steel velocity and the shedding frequency of Karman’s vortex streets, which are formed behind a circular cylinder immersed in the molten-steel flow field. Calibration of the probe was made in the absence of, as well as in the presence of, mold powder. The adequacy of the presently developed Karman vortex probe was verified partly by comparing the molten-steel velocity data measured in actual continuous-casting molds to those obtained using a water model with the same shape and size as the actual mold. The meniscus-flow velocity in the absence of electromagnetic braking increased and then slightly decreased with an increase in the casting speed.     

3.5-mm-square InGaAs p-i-n photodiodes and their application tooptical-axis arrangement between 1.3-μm laser diodes and a SMF

InGaAs p-i-n photodiodes (PD) with 3.5-mm×3.5-mm-large photosensitive area have been fabricated using chlorine-vapor-phase-epitaxial (C-VPE) growth. They showed high responsivity of 0.95 A/W (λ=1.3 μm) and 1.2 A/W (λ=1.55 μm) and good homogeneity in the whole area. Long-term reliability was confirmed through high-temperature aging tests at 150°C up to 5200 hours. A PD with two pairs of parallel electrodes (PE-PD) was applied to optical-axis arrangement between 1.3-μm laser diodes (LD's) and a single mode fibre (SMF). The beam position of a LD was detected in error within ±20 μm using PE-PD prior to coupling of a LD beam into a SMF. Total inspection time was reduced to one third the original time     

Local lattice parameter determination of a silicon (001) layer grown on a sapphire (1102) substrate using convergent-beam electron diffraction

All the six lattice parameters (a, b, c, alpha, beta and gamma) of a Si (001) layer grown on a sapphire (1102) substrate were determined by convergent-beam electron diffraction with no assumption of crystal lattice symmetry. A lattice compression in the Si (001) plane and an elongation in the [001] direction were revealed. An anisotropic lattice compression in the (001) plane was clearly detected for the first time. That is, the lattice compression in the Si [100] direction, which is parallel to the sapphire [1101] direction, was larger than that of the Si [010] direction, which is parallel to the sapphire [1120] direction. It was also revealed that the lattice parameters of the Si-layer depend on the distance from the interface. Anisotropy of carrier mobility was reasonably explained in terms of the anisotropy of the lattice parameters determined.     

A possible buckybowl-like structure of zeolite templated carbon

Ordered microporous carbon that was synthesized in the nanochannels of zeolite Y is characterized by an extremely large surface area, surprisingly uniform micropores and a long-range periodicity originating from the parent zeolite. However, the molecular structure of this zeolite templated carbon (ZTC) has been completely unknown. In this study, an attempt was made to construct a possible molecular model for ZTC. The proposed model is made up of buckybowl-like nanographenes assembled into a three-dimensionally regular network, which reflects all the experimental results obtained from Raman spectroscopy, electron energy-loss spectroscopy, and previously obtained analyses with several other means. Starting from this idealized model, possible forms of defects that would be included in the actual ZTC were also investigated. Moreover, the amount and the type of oxygen functional groups were analyzed and, as per the results, some functional groups were bound to the edge sites of each buckybowl unit in the molecular model. The elemental composition, pore curvature, pore size and pore volume and surface area estimated from such oxygen-containing model agree well with the corresponding experimentally obtained results. The present model can be considered as a reasonable starting point for future refinements of the structure of this quite novel carbon material.     

Prediction of blood lactate accumulation from excess CO2 output during constant exercise

To determine the predictability of blood lactate accumulation from excess CO2 output derived from bicarbonate buffering of lactic acid during constant exercise, eight normal active volunteers were studied during three stages of constant exercise on a cycle ergometer. Three work rates consisted of 100% (stage I), 120% (stage II) and 150% (stage III) of each subject's anaerobic threshold (AT), each of which was lasted for 4 min. Excess CO2 output (Ex CO2, ml) at each stage of constant exercise was estimated form the integral of difference between total VCO2 and aerobic VCO2 (from regression line for VCO2 and VO2 at exercise intensities below the AT obtained in incremental exercise test). Ex CO2 per body mass (Ex CO2-mass-1) was increased progressively with blood lactate (La) accumulation from rest to each stage of constant exercise. Mean values (+/-SD) in the measured La accumulation (delta La,measured) and predicted La accumulation (delta La,predicted) at three stages of constant exercise were 1.82 +/- 0.83 vs 3.19 +/- 1.70 for stage 1, 5.58 +/- 3.47 vs 7.09 +/- 3.28 for stage II and 12.19 +/- 2.36 vs 12.74 +/- 1.83 mmol.l-1 for stage III, respectively. There was a significant difference between delta La,measured and delta La,predicted at stage I (p < 0.05), but no significant differences between these two variables at stage II and III. The averaged difference from delta La,predicted to delta La,measured at stage III (0.55 mmol.l-1) showed a tendency to be smaller than stage I (1.38 mmol.l-1) and II (1.50 mmol.l-1). On the other hand, delta La,predicted was found to correlate very closely with delta La,measured (r = 0.954, P < 0.001, n = 20). The results of this study suggest that the changes of La accumulation could be predicted from excess CO2 output generated in constant exercises above the AT.     

Involvement of p85 in p53-dependent apoptotic response to oxidative stress

Reactive oxygen species have damaging effects on cellular components and so trigger defensive responses by the cell and even programmed cell death, although the mechanisms by which mammalian cells transmit signals in response to oxidative damage are unknown. We report here that the protein p85, a regulator of the signalling protein phosphatidyl-3-OH kinase (PI(3)K), participates in the cell death process that is induced in response to oxidative stress and that this role of p85 in apoptosis does not involve PI(3)K. We show that disruption of p85 by homologous recombination impairs the cellular apoptotic response to oxidative stress. Because the protein p53 is required for cell death induced by oxidative damage, we examined the relation between p85 and p53. Using a chimaeric p53 fusion protein with the oestrogen receptor (p53ER) to supply p53 (p53 is induced upon binding of p53ER to oestradiol) in a p53-deficient cell line, we found that p85 is upregulated by p53 and that its involvement in p53-mediated apoptosis is independent of PI(3)K. We propose that p85 acts as a signal transducer in the cellular response to oxidative stress, mediating cell death regulated by p53.     

Preparation of Au/ZnO nanocomposites by radio frequency co-sputtering

Au/ZnO nanocomposite films were prepared by co-sputtering of ZnO and gold wires. The composite films were transparent and red in color due to surface plasmon resonance absorption of small Au particles. The composite films were annealed at different temperatures in argon atmosphere to study the evolution of the size of Au particles and subsequent change in their optical properties. With the increase of annealing temperature, the size of the Au particles increased and the intensity of plasmon resonance absorption peak increased.     

Optical WDM transceiver module using wavelength-selective couplerand WDM-PD for optical access networks

A new optical wavelet division multiplexing (WDM)-transceiver module has been designed and fabricated for optical access networks. Conventional 1.3/1.55-μm WDM-coupler and Y-branch were replaced by a new wavelength-selective coupler in order to reduce module size. A new WDM-photodiode (PD), which was photosensitive to 1.3 μm light and transparent to 1.55 μm light, and a 1.55-μm PD were arranged in series along the optical axis. An MQW-FP-LD was used as a 1.3-μm transmitter. Fundamental characteristics were measured and discussed. Evaluation results, P_out of 0 dBm, responsivity of 0.36 A/W at 1.31 μm and 0.74 A/W at 1.55 μm, and IMD2 of -76.2 dBc, imply that this WDM-transceiver module design is promising to application for optical access networks