The preparation and properties of thin silicon films deposited on amorphous substrates by cathodic sputtering

Spectrographic analysis reveal that the only essential difference between films sputtered from the differenct source materials was the presence in the films of the intentional source impurities. In view of the marked differences in resistivities observed it is believed that the electrical behavior of the crystalline films is dominated by impurity effects

文献情報のデータベース化と目録作成のシステム化

国立国語研究所1989年度より，国語年鑑と図書館のシステム化を目的とした作業を開始した。このシステムは研究所における文献情報の収集，整理，2次情報の作成に関しての計算機によるシステム化を目指したものである。それまでは手作業で行われていた作業を機械化し，作業の効率化と機械可読データの蓄積によるデータの有効利用によって，研究所における継続的な文献データベース作成のためのシステムの基礎作りを目指したものである。1994年度までに，国語年鑑に関する機械化を目指した範囲の全体をおおうことができた。この報告では，これまでの経過をまとめつつ，文献情報のデータベース化と目録作成のシステム化のために行った作業のうち，特にこの国語年鑑の機械化に関わる部分について報告した。システムはパーソナルコンピュータ上に構築した。This paper reports on the development of the information system for Kokugo Nenhan (Japanese Language Yearbook),the annual bibliography which covers all fields of Japanese linguistics, published by the National Language Research Institute since 1953. In this paper, we describe the data entry system, the structure of the database and the processing procedure employed for publication.We started this project in 1989, developing an information system for compiling a comprehensive bibliographic database of the study of Japanese language, and for publishing the bibliography by processing the database. The system aims to replace the process of manually editing Kokugo Nenkan by a computeraided, database-oriented system, and to make the results available on electronic media. At the same time, we started another project to develop the library information system. It was intended that the two projects, which are mutually autonomous but closely related, would form the basis of the NLRI bibliographic information system.1-16の書名 : 研究報告

〈共同研究プロジェクト紹介〉独創・発展型 : 大規模方言データの多角的分析 『日本言語地図』のデータベース化が開く新たな研究

国立国語研究所時空間変異研究系『日本言語地図』のデータベース化(『日本言語地図』データベース,LAJDB)の概略を説明し,3年間の本プロジェクト期間中に整備を進め,利用可能となった項目(119項目)の一部を利用した計量的な分析の事例として,標準語形の使用数の地理的な分布を示した。これにより,『日本言語地図』がデータベース化されることの意味とこれが生み出す新しい研究の広がりの一端に触れた。The Linguistic Atlas of Japan (LAJ, 6 vols.) was published from 1966 to 1974 by the National Language Research Institute, the present NINJAL. In 1999, we started constructing the Linguistic Atlas of Japan Database (LAJDB). In this three-year project, we accelerated the construction process. Various quantitative studies have been done on LAJ since its publication, but the lack of data in digital form has restricted the development of such quantitative research. As a case study of quantitative analysis using LAJDB, we made some observations on the geographical distribution of the frequency (GDF) of standard forms. The GDF of standard forms for each locality showed clear patterns which could not be obtained from the prefecture-unit calculations of former studies. Such "high resolution" patterns obtained from LAJDB enable us to trace diffusion routes more precisely. We compared these geographical distributions with the network of roads and so on, and found interesting relationships among them

Time-resolved measurements of two-color laser light emitted from GaAs/AlGaAs-coupled multilayer cavity

We measured the two-color laser oscillation from a GaAs/AlGaAs-coupled multilayer cavity at 18–42 °C using current injection. We confirmed simultaneous lasing by detecting the sum frequency generation signal generated by the two-color laser light, and performed time-resolved measurement using a streak camera with a spectrometer. From the observed time transient of the spectra at various temperatures, it it is clarified that the temperature change of the device, induced by current injection, modulates the effective cavity length. Therefore, the temperature control of the device is a key factor in stable two-color lasing and THz wave generation

Sublattice reversal in GaAs/Ge/GaAs heterostructures grown on (113)B GaAs substrates

GaAs/Ge/GaAs heterostructures were grown on high-index (113)B GaAs substrates by molecular beam epitaxy. Sublattice reversal in GaAs/Ge/GaAs was identified by comparing the anisotropic etching profile of the epitaxial sample with that for reference (113)A and (113)B GaAs substrates. The shape of the resulting mesa for the lower GaAs layer was similar to that for the reference (113)B GaAs substrate, whereas that for the upper GaAs layer was similar to that for the reference (113)A GaAs substrate. An atomic-resolution analysis was also conducted by mapping using energy-dispersive X-ray spectroscopy, whereby the sublattice reversal was directly observed through the atomic arrangements

Room-temperature two-color lasing by current injection into a GaAs/AlGaAs coupled multilayer cavity fabricated by wafer bonding

Room-temperature two-color lasing was demonstrated by current injection into a GaAs/AlGaAs coupled multilayer cavity for terahertz emitting devices utilizing its difference-frequency generation (DFG) inside the structure. We prepared two epitaxial wafers with (001) and (113)B orientations and they were directly bonded to form the coupled multilayer cavity. The (001) side cavity contains two types of InGaAs multiple quantum wells to realize optical gain for two-color lasing while a single GaAs layer of the (113)B side cavity is a nonlinear medium for efficient DFG. Lasing behavior was clearly observed for two modes under pulsed current conditions at room temperature. We found that intensity relation between two-color lasing was dependent on the pulse duration due to the different temporal profiles of emission intensity. Simultaneous two-color lasing in the device was also confirmed by measuring the sum-frequency generation signal using a beta barium borate crystal

Current-injection two-color lasing in a wafer-bonded coupled multilayer cavity with InGaAs multiple quantum wells

Current-injection two-color lasing has been demonstrated using a GaAs/AlGaAs coupled multilayer cavity that is a good candidate for novel terahertz-emitting devices based on difference-frequency generation (DFG) inside the structure. The coupled cavity structure was fabricated by the direct wafer bonding of (001)- and (113)B-oriented epitaxial wafers for the efficient DFG of two modes in the (113)B side cavity, and two types of InGaAs multiple quantum wells (MQWs) were introduced only in the (001) side cavity as optical gain materials. The threshold behavior was clearly observed in the current–light output curve even at room temperature. Two-color lasing was successfully observed when the gain peaks of MQWs were considerably tuned to the cavity modes by the operating temperature

Two-color surface-emitting lasers by a GaAs-based coupled multilayer cavity structure for coherent terahertz light sources

Two-color surface-emitting lasers were fabricated using a GaAs-based coupled multilayer cavity structure grown by molecular beam epitaxy. InGaAs/GaAs multiple quantum wells were introduced only in the upper cavity for two-mode emission in the near-infrared region. Two-color lasing of the device was successfully demonstrated under pulsed current operations at room temperature. We also observed good temporal coherence of the two-color laser light using a Michelson interferometer. A coherent terahertz source is expected when a wafer-bonded coupled cavity consisting of (001) and non-(001) epitaxial films is used for the two-color laser device, in which the difference-frequency generation can be enabled by the second-order nonlinear response in the lower cavity