Modal and relative intensity noise under VHF modulation in InGaAsP/InP lasers before and after degradation

The modal and relative intensity noise of InGaAsP/InP lasers are monitored before and after degradation. These noise levels under VHF modulation are scarely affected by laser degradation and are almost determined by VHF modulation, although the noise levels under DC bias increase after degradation.     

Development of new‐type outdoor termination using composite insulator with SF6 gas: Commercial use for 77‐kV transmission lines and development for 154‐kV XLPE cable

Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF₆ gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF₆ gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511     

Discovering characteristic patterns from collections of classical Japanese poems

Waka is a form of traditional Japanese poetry with a 1300-year history. In this paper, we attempt to discover characteristics common to a collection ofwaka poems. As a schema for characteristics, we use regular patterns where the constant parts are limited to sequences of auxiliary verbs and postpostional particles. We call such patternsfushi. The problem is to automate the process of finding significantfushi patterns that characterize the poems. Solving this problem requires a reliable significance measure for the patterns. Brāzma et al. (1996) proposed such a measure according to the MDL principle. Using this method, we report successful results in finding patterns from five anthologies. Some of the results are quite stimulating, and we hope that they will lead to new discoveries. Mayumi Yamasaki, M.A.: She received her B.E. and M.A. degrees from Kyushu Institute of Technology in 1997 and from Kyushu University in 1999, respectively. Her research interests include machine discovery and datamining. Presently, she works at Fujitsu FIP Corporation. Masayuki Takeda, Dr. Eng.: He is an Associate Professor in Department of informatics at Kyushu University. He received his B.S., M.S., and Dr. Eng. degrees from Kyushu University in 1987, 1989 and 1996 respectively. His present research interests include pattern matching algorithims, text compression, discovery science, information retrieval and natural language processing. He is a member of Information Processing Society of Japan, Japanese Society for Artificial Intelligence and Japanese Society for Soft-ware Science and Technology. Tomoko Fukuda, M.A.: She is a Lecturer at Fukuoka Jo Gakuin University and at Junshin Women’s Junior College, She received her B.A. and M.A. degrees from Fukuoka Women’s University in 1987 and from Kyushu University in 1992 respectively. Her present research interests are in Japanese literature in the Heian period and classical 31-syllable Japanese poems. She is a member of Waka-Bungaku Kai (Society for Study of Japanese Poems) and Chuko-Bungaku Kai (Society for Study of Japanese Literature in the Heian Period). Ichiro Nanri, M.A.: He is an Associate Professor at Junshin Women’s Juior College. He received his B.A. and M.A. degrees from Kyushu University in 1990 and 1995 respectively. His present research interests are in Japanese language in the Heian-Kamakura period and classical 31-syllable Japanese poems. He is a member of Kokugo Gakkai (Society for Study of Japanese Language) and Kuntengo Gakkai (Society for Studyy of Old Language).     

Organic LED full-color passive-matrix display

Abstract— A full-color 5.2-inch 1/4-VGA passive-matrix organic LED display has been developed, adopting selective deposition for the different emitting materials. The display features 320 (×3) × 240 pixels with an equivalent pixel size of 0.33 × 0.33 mm, white peak luminance of over 150 cd/m², and power consumption of 6 W.     

Development of a high-efficiency H2 feeder for bioremediation.

An electrochemical dissolved hydrogen feeder equipped with a multi-cathode system and a high-rate recirculation pump was developed in order to examine its feasibility for bioremediation. Results showed that the feeding efficiency was remarkably higher than that in former studies. The reason for the enhanced hydrogen dissolution rate was thought to be due to the large cathode area by applying multiple granular activated carbon electrodes resulting in low current density. Two mass balance equations were formulated and applied to analyze the performance of the apparatus theoretically. The hydrogen dissolution rate calculated from the equations was in fairly good agreement with observed results. It was suggested that the electrochemical H2 feeder would be a competitive alternative as a hydrogen feeding method for bioremediation.     

Suppression of interface degradation in InGaAsP inP buried heterostructure lasers

In InGaAsP/InP buried heterostructure (BH) lasers, the degradation of BH interface between first- and second-growth step layers can be suppressed by employing the melt back process just before the second-step layer growth. It is confirmed this burying process give more reliable BH lasers than the conventional burying process. From the viewpoint of BH interface degradation, lasers lasing at 1.5 μm, where the melt back process naturally occurs during BH formation, are found to be more reliable than those lasing at 1.3 μm.     

High-power 0.98 mu m GaInAs strained quantum well lasers for Er/sup 3+/-doped fibre amplifier

High-power GaInAs strained quantum well lasers with an emission wavelength of 0.98 mu m, suitable for Er/sup 3+/-doped fibre amplifier pumping, have been fabricated. A threshold current of 15 mA and a peak output power as high as 85 mW have been obtained for the ridge waveguide structure with AR/HR facet coating. Highly efficient pumping for the 1.536 mu m signals has been confirmed.<>     

A case of retinal detachment in Kniest dysplasia treated with vitreous surgery

We report a case of retinal detachment with Kniest dysplasia for which vitreous surgery was effective. The patient was a 7-year-old female who had the typical ocular and physical findings of this disease. Visual acuity was light perception alone due to a hypermature cataract and bullous retinal detachment. We performed cataract surgery and pars plana vitrectomy, and used silicone oil tamponade. After seven months, the silicone oil was removed, and visual acuity improved to 0.09. We conclude that bullous retinal detachment with Kniest dysplasia can be treated by vitreous surgery in combination with the use of silicone oil tamponade.