Room temperature continuous wave operation of GaInP/AlInP visible-light laser with GaInP/AlInP superlattice confinement layer grown by gas source molecular beam epitaxy

A remarkable threshold current density reduction (from 3.5 kA/cm/sup 2/ to 1.6 kA/cm/sup 2/) of GaInP/AlInP visible light lasers grown by gas source molecular beam epitaxy (GS-MBE) was obtained by introducing 50 pairs of GaInP(7.1 AA)/AlInP(7.1 AA) short period superlattice confinement (SLC) layers. As a result, the room temperature continuous wave (CW) operation was obtained at 669 nm with a minimum threshold current of 50 mA and maximum light output of 10.5 mW.<>     

High-speed GaN growth and compositional control of GaN-AlGaNsuperlattice quasi-ternary compounds by RF-radical source molecular beamepitaxy

Novel growth technologies of III-nitrides for fabricating optical devices by molecular beam epitaxy using RF-plasma excited nitrogen (RF-MBE) were investigated. A relatively high-growth rate, up to 1.4 μm/h of GaN with high-electrical and high-optical quality was obtained. The concept of AlGaN quasi-ternary (QT) compounds, consisting of GaN-AlGaN short period superlattice, was demonstrated and the Al composition was controlled with a shutter control method in the range of 0-0.47. Using the QT technology, a GaN-Al_0.07Ga_0.933N-Al_0.3Ga_0.7 N multiquantum-well heterostructure was fabricated to show the effectiveness of the method     

High Field ESR System and Its Application to the Study of Quantum Spin Systems

Developments of the high field ESR system in Kobe University is presented. Using Gunn oscillators and backward traveling oscillators (BWO), we can cover the frequency region from 30 to 1183.6 GHz with the use of InSb detector. Pulsed magnetic field up to 30 T is available and we are now trying to extend the field up to 40 T. Temperature range is from 1.8 to 300 K. Using this system, we studied S=1/2 ladder like system Cu₂(C₅H₁₂N₂)₂Cl₄, and found a new magnetic transition at 10.1 T at 1.8 K. The temperature dependence of ESR in Cu₂(C₅H₁₂N₂)₂CI₄ shows g-shift below 8 K which corresponds to the maximum of the magnetic susceptibility. The g-shift below 8 K suggests the increase of the quantum fluctuation in the system, and the role of the quantum fluctuation in Cu₂(C₅H₁₂N₂)₂CI₄ is discussed.     

Organic Analysis of Peridotite Rocks from the Ashadze and Logatchev Hydrothermal Sites

This article presents an experimental analysis of the organic content of two serpentinized peridotite rocks of the terrestrial upper mantle. The samples have been dredged on the floor of the Ashadze and Logatchev hydrothermal sites on the Mid-Atlantic Ridge. In this preliminary analysis, amino acids and long chain n-alkanes are identified. They are most probably of biological/microbial origin. Some peaks remain unidentified.     

Newly structured expandable 52-Mbit/s, 48-channel time-division switching LSI with 2.4 Gbit/s throughput

An expandable Si bipolar 2.4 Gbit/s throughput, 52 Mbit/s 48-channel time-division switching LSI system is described. A high-throughput of 2.4 Gbit/s and a power-dissipation of 5.3 W are achieved by adopting a low-voltage swing four-serial-gated differential bipolar circuit design and super self-aligned process (SST-1A) logic-in-memory LSI technology. This LSI is applicable to the digital video time-division switching and digital crossconnect systems of future B-ISDN.<>     

Gigahertz band GaAs monolithic limiting amplifier

The letter presents the design and performance of a gigahertz band limiting amplifier IC using GaAs MESFET IC technology. With a two-chip connection, an AM/PM conversion of 0.7°/dB over 43 dB input dynamic range at 1 GHz has been achieved.     

中国徽州地区农村传统村落街区空间构造的形成——对古徽州地区呈坎村与卢村的调查

街区是构成中国传统村落的基本组团单位，其潜在的含义是居住者的社会组成。本文从社会构成的角度分析街区所反映出来的村落空间形式。     

Effect of catalyst combination on growth of single-walled carbon nanotubes

A new effective catalysts combination of iron — nickel for alcohol CVD technique was found. This catalyst catalyzed well as well as the typical catalyst of iron — cobalt catalysts, but gave a different diameter distribution. Calculating their electrical density of states under the assumption of their solid lattice structures, the result was fairly consistent with experimental results. The number of electrical states near Fermi level that is considered to be important for catalytic reaction is enough and the DOS of iron – nickel catalyst was quite similar to that of cobalt unlike manganese – copper catalyst. Consequently, a blend of catalysts that has a similar DOS to cobalt and has enough states near the Fermi level can be a good catalyst for alcohol CVD.     

Effect of 1/f-type FM noise on semiconductor-laserlinewidth residual in high-power limit

The FM-noise spectrum and the linewidth of 1.3 μm DFB (distributed feedback) semiconductor lasers measured in the high-power state up to 20 mW are discussed. A 5-MHz residual linewidth is observed in the high-power limit. The FM-noise spectrum consists of white noise and 1/f noise. The spectral density of the white noise is reduced by the increase in the output power, whereas that of the 1/f noise is unchanged, which means that the linewidth residual in the high-power limit is caused by the 1/f noise rather than the white noise. The impact of the 1/f-type FM noise on coherent optical communication systems is also discussed