Highly reliable uni-travelling-carrier photodiodes for 40 Gbit/soptical transmission systems

The reliability of InP/InGaAs uni-travelling-carrier photodiodes has been studied. A failure rate of 42 FIT at 25°C was estimated from long-term bias-temperature stress tests. Stable operations for over 2000 h were also confirmed under higher-power optical input conditions     

Optical clock-pulse-train generator for processing preamble-free asynchronous optical packets

An optical clock-pulse-train generator (OCPTG) for processing asynchronous arbitrary-length optical packets with no preamble is developed. The OCPTG consists of a fiber-loop-based optical pulse-train generator (PTG) and an optical clock-pulse generator that, for every input asynchronous optical packet, generates a single, synchronized optical pulse which is fed to the PTG. Generation of an optical clock-pulse-train with stable pulse energy, precise repetition rate, and duration matching the input packet is achieved for variable-length optical packets. The OCPTG and an all-optical demultiplexer combined demonstrate error-free demultiplexing of a 10-Gb/s asynchronous optical packet stream.     

Strategic CAE system for the design of calibre in the rolling of complex sections

A new strategic CAE system for calibre design in the rolling of complex sections is proposed. This system is composed by combining CAD system with a three‐dimensional rigid‐plastic finite element simulator for the rolling, and can give us deformation and force characteristics such as final geometry, rolling force, rolling torque, thrust force, bending of product, and so on. As the human interface of the proposed system is designed on the basis of CAD, experts in calibre design can operate it easily, and important information usable for calibre design can be given after the numerical computation on computers. The basic construction of this system is described in this paper. Several results of applications to calibre design in the rolling of complex and asymmetric sections are shown. Finally, the advantages of a CAE system for calibre design will be discussed by the achievements obtained through industrial calibre design in the last ten years.     

Application of a fiber optic grating strain sensor for the measurement of strain under irradiation environment

In the Japan Atomic Energy Research Institute (JAERI), in-pile strain measurement techniques have been developed using the Japan Materials Testing Reactor (JMTR). In order to evaluate the performance of fiber optic grating sensors under irradiation environment, heat-up and performance tests at elevated temperatures before irradiation and in-pile tests were performed in JMTR. It was determined that it is possible to measure strain under irradiation environment below 1×10²³ n m⁻² (E>1 MeV) by a fiber optic grating sensor, because in-pile temperature characteristics were in good agreement with out-of-pile test results.     

Real-time evaluation of the effectiveness of microwave coagulation therapy for hepatocellular carcinoma using color Doppler imaging

The patient's insight in the course of a mental disease has recently become a matter of interest for psychiatrists. Various aspects of insight are examined, as well as the relationship between insight and different clinical variables. In the current study, we examined correlations between aspects of insight and intensity of psychopathological symptoms, occurrence of the various types of delusions, and the level of premorbid adjustment in patients with paranoid schizophrenia. We found significant relationships between poor insight and negative symptoms, thought-broadcasting, delusions of grandeur and sexual delusions, and worse premorbid adjustment in late adolescence and adulthood.     

Roasting effects on fatty acid distribution of triacylglycerols and phospholipids in the kernels of pumpkin (Cucurbita spp) seeds

In this study, changes in fatty acid distributions of pumpkin seeds (Cucurbita spp) in the course of the roasting process were investigated. Whole pumpkin seeds were exposed to microwaves for 6, 12, 20 or 30 min at a frequency of 2450 MHz. The kernels were separated from the seeds, and the lipid components and the fatty acid distributions of triacylglycerols (TAGs) and phospholipids (PLs) were analysed by a combination of thin layer chromatography and gas chromatography. Major lipid components were TAGs, free fatty acids (FFAs) and PLs, while steryl esters and diacylglycerols were also present in minor proportions. The greatest PL losses (p < 0.05) were observed in phosphatidyl ethanolamine, followed by phosphatidyl choline or phosphatidyl inositol. With a few exceptions, significant differences (p < 0.05) in fatty acid distributions occurred when the seeds were microwaved for 20 min or more. Nevertheless, the positional characteristics of fatty acid distributions in the TAGs were still retained after 20 min of roasting: unsaturated fatty acids were predominantly concentrated in the sn‐2‐position, and saturated fatty acids primarly occupied the sn‐1‐ or sn‐3‐position. These results suggest that no significant changes in fatty acid distribution of TAGs and PLs would occur within 12 min of microwave roasting, thus ensuring that a good‐quality product would be obtained. Copyright © 2005 Society of Chemical Industry     

X-ray photoemission spectroscopy analysis of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells

We report on the electronic structure of three different types of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells observed by hard X-ray photoemission spectroscopy. Prepared samples are derived from: (1) melamine and poly(furfuryl alcohol), (2) nitrogen-doped carbon black and (3) cobalt phthalocyanine and phenolic resin. C 1s spectra show the importance of sp² carbon network formation for the oxygen reduction reaction (ORR) activity. N 1s spectra of the carbon-based cathode catalysts are decomposed into four components identified as pyridine-like, pyrrole- or cyanide-like, graphite-like, and oxide nitrogen. Samples having high oxygen reduction reaction activity in terms of oxygen reduction potential contain high concentration of graphite-like nitrogen. O 1s spectra are similar among carbon-based cathode catalysts of different oxygen reduction reaction activity. There is no correlation between the ORR activity and oxygen content. Based on a quantitative analysis of our results, the oxygen reduction reaction activity of the carbon-based cathode catalysts will be improved by increasing concentration of graphite-like nitrogen in a developed sp² carbon network.     

A common‐source active clamped complex type converter

This paper presents a novel common‐source active clamped complex type converter. This converter is the intermediate isolated bus converter for the distributed power supply system in telecommunications equipment. Using active clamped circuits, the switching loss and switching noise can be reduced by means of the soft switching techniques. By adding an auxiliary winding to the transformer, the proposed converter is a common‐source type having direct connection of sources of the two MOSFET switches. As a result, the pulse transformer becomes unnecessary, and the drive circuit is simplified. In the experiment, at 48 V ratings input voltage, 36 to 72 V worldwide input voltage, and 12 V output voltage, the ZVS operation is performed on the main switch and auxiliary switch, and highest efficiency 92.7% is obtained. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 64–70, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20682     

Ab initio study on geometrical structures of the TTTA molecular crystal

The crystal made of organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), exhibits a large first-order magnetic and structural phase transition between a paramagnetic high-temperature (HT) phase and a diamagnetic low-temperature (LT) phase, with a surprisingly wide thermal hysteresis loop over room temperature. We investigate theoretically the crystal structures for the two phases by means of the ab initio structural optimization method based on the local density approximation. We present necessary and sufficient atomic coordinates in this paper. The resulting structures are in good agreement with the recent X-ray diffraction experiment. In the HT phase, uniform one-dimensional stacking of the radical molecule appears, while, in the LT phase, strong dimerization along the stacking direction appears.