Photoluminescence of R-Lines in Alexandrite under High Magnetic Field and High Pressure(Magnetooptics)

The photoluminescence of R-lines due to the (CrO_6)^ center in alexandrite has been measured under pressures up to 15 GPa at room temperature and 77 K. The results show that the symmetry of the effective crystalline field, being orthorhombic at 1 atm, tends to become trigonal as pressure increases. To examine the influences of this symmetry change on the magnetic properties, the Zeeman spectrum has been measured under magnetic fields up to 15 T at 77 K. The Paschen-Back effect is found to develop under pressures near 8 GPa if the field is applied parallel to the b- and c-axes. This finding demonstrates that the character of the spins of the excited states involved in the R-lines changes as if it is transformed from the Heisenberg-type to the Ising-type. Some structural instability is suggested to occur above about 8 GPa at 77 K and about 11 GPa at room temperature

Al2O3/TiO2 double layer anti-reflection coating film for crystalline silicon solar cells formed by spray pyrolysis

An Al2O3/TiO2 double layer anti-reflection coating (ARC) film formed by spray pyrolysis was introduced for monocrystalline silicon solar cells as the nonvacuum processing method. The thickness of the Al2O3 layer and TiO2 compact layer was controlled by the volume of deposited precursor solution and confirmed by ellipsometry and scanning electron microscopy. The average photovoltaic properties of photocurrent density (Jsc), open-circuit photovoltage (Voc), fill factor (FF), and photo energy conversion efficiency (η) were 37.0 mA/cm2, 590 mV, 0.712, and 15.5%, respectively. A significant improvement on Jsc and η could be confirmed owing to the Al2O3/TiO2 ARC. The results of Fourier transform infrared (FTIR) spectroscopy and optical simulation with modeling for the reflectance properties confirmed that C-H-based organics remained after the deposition of thin films

300 Mbps Downlink Communications from 50kg Class Small Satellites

Recently small satellites start playing important roles in earth observation missions. It, however, is true that small satellites have drawbacks of sensor resolutions and down link data rate. As a solution to the latter drawback, we have developed novel communications system for 320Mbps down link with 16QAM for small satellites with 50kg class. We developed a new GaN HEMT X-band amplifier with high efficiency and small distortion, digital filter and pre-distortion processing with relatively low clock frequency in FPGAs, and small X-band on-board antennas. As ground segments, we are developing a compact S/X dual band ground antenna station and a high performance demodulator with turbo equalizer/decoder based on CCSDS high rate telemetry standard. These technologies will be demonstrated in 2014 by Japanese Hodoyoshi-4 satellite with 50 kg mass

火山活動の評価手法の開発と火山防災情報に関する研究(序報)

ワークショップの開催、実践的な教育・普及活動に取り組み、火山防災情報の質の向上にかかわる問題点の整理がかなり進んだ。また、火山活動の評価手法を目指して、薩南諸島の火山において地磁気の連続観測、近年開発されたDOASによる二酸化硫黄の放出率の測定等を行い、また、過去30年間の桜島の火山灰中の揮発成分の分析を行い、他の観測調査データ等と比較することによって、これらの観測・分析手法が火山活動評価や噴火機構研究の有効なツールとなりうることを確認した。さらに、複数の火山の火山性地震を自動分類し、その結果を必要に応じて携帯電話やE-mailで関係者に通報するシステムを開発し、試験運用を開始した。This paper is a preliminary report that describes the outline of targets and present results of our research project. Problems on volcanic information and education for mitigation of volcanic hazards fairly became clear by a workshop and educational activity. Present results on new tools applied for volcano monitoring at active volcanoes in southern Kyushu are described; geomagnetic observation, remote sensing for volcanic gases, and so on. Basic concept of a system of information processing on seismic data is described.ワークショップの開催、実践的な教育・普及活動に取り組み、火山防災情報の質の向上にかかわる問題点の整理がかなり進んだ。また、火山活動の評価手法を目指して、薩南諸島の火山において地磁気の連続観測、近年開発されたDOASによる二酸化硫黄の放出率の測定等を行い、また、過去30年間の桜島の火山灰中の揮発成分の分析を行い、他の観測調査データ等と比較することによって、これらの観測・分析手法が火山活動評価や噴火機構研究の有効なツールとなりうることを確認した。さらに、複数の火山の火山性地震を自動分類し、その結果を必要に応じて携帯電話やE-mailで関係者に通報するシステムを開発し、試験運用を開始した。This paper is a preliminary report that describes the outline of targets and present results of our research project. Problems on volcanic information and education for mitigation of volcanic hazards fairly became clear by a workshop and educational activity. Present results on new tools applied for volcano monitoring at active volcanoes in southern Kyushu are described; geomagnetic observation, remote sensing for volcanic gases, and so on. Basic concept of a system of information processing on seismic data is described

High Bit-rate Communication in X Band for Small Earth Observation Satellites - Result of 505 Mbps Demonstration and Plan for 2 Gbps Link

A compact 64APSK X band transmitter for small satellites with maximum 538 Mbps, mass of 1.3 kg, and power consumption of 22 W has been developed. This transmitter was onboard on Hodoyoshi 4 satellite with 66 kg mass and 505 Mbps downlink was demonstrated. The main characteristics of this downlink system are as follows: i) GaN HEMT X band power amplifier with a high power efficiency and a small nonlinear distortion, ii) application of an error correction code (SCCC, CCSDS 131.2-B-1) with high coding gain. We present a plan of 2-3 Gbps downlink system in X band