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Manabe T.,Osaka Prefecture University | Nishibori T.,Japan Aerospace Exploration Agency | Mizukoshi K.,Advanced Engineering Services Co. | Otsubo F.,Advanced Engineering Services Co. | And 3 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2012

This communication describes the results of the measurements made for the flight model of the offset Cassegrain antenna of superconducting submillimeter-wave limb-emission sounder (SMILES) aboard the International Space Station. We have employed a near-field phase retrieval method in which the aperture phase distribution is estimated only from the amplitude distribution measurements over two near-field planes. The far-field patterns estimated from the estimated near-field patterns were compared with theoretical calculations based on physical optics in which the surface errors measured for the main and sub reflectors were taken into account. As a result of the comparison, the far-field patterns estimated from the phase retrieval method were found to be in very good agreement with the physical-optics calculations to the sidelobe levels as low as 55 dB. We have also found that patterns of machined flaws on the surface of the main reflector were clearly identified in the retrieved near-field phase pattern. This demonstrates that the phase retrieval is an effective method to evaluate aperture antennas in the submillimeter-wave region, where accurate phase measurement is rather difficult. © 1963-2012 IEEE.

Suzuki S.,Advanced Engineering Services Co.
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C | Year: 2013

Generally, many space satellites have large solar array panels for power generation and large antennas for observation and communication. The panels and antennas must be lightweight because of the payload weight limit of the launch vehicle. So, they are very flexible, with little damping ability. This results in vibrations cause serious problems. When the thermal environment around a flexible structure on orbit such as a solar array panel changes to cold or hot, the flexible structure produces its own deformation or vibration. These occur most often during rapid temperature changes called thermal snap or thermally-induced vibration, which has been known to cause attitude disturbance in Low Earth Orbit (LEO) satellites. Thermal snap vibration occurring on a flexible solar array panel is very slow. It is very difficult to measure thermal snap motion by sensors such as accelerometer. The behavior of a space structure affected by thermal snap has never been observed directly in space so far. This report presents the measurement results of "IBUKI" solar array panel's behavior using monitor camera. © 2013 The Japan Society of Mechanical Engineers.

Ishikawa T.,Japan Aerospace Exploration Agency | Paradis P.-F.,Japan Aerospace Exploration Agency | Okada J.T.,Japan Aerospace Exploration Agency | Kumar M.V.,Japan Aerospace Exploration Agency | Watanabe Y.,Advanced Engineering Services Co.
Journal of Chemical Thermodynamics | Year: 2013

Viscosities of tungsten, rhenium, osmium, tantalum, and molybdenum have been measured by the oscillation drop method with an improved procedure. The measured data exhibit less-scatter than our previous measurements. Viscosity at the melting temperature of the investigated metals showed a good agreement with literature values and some predicted values. © 2013 Elsevier Ltd. All rights reserved.

Ishikawa T.,Japan Aerospace Exploration Agency | Ito Y.,Shibaura Institute of Technology | Okada J.T.,Japan Aerospace Exploration Agency | Paradis P.-F.,Japan Aerospace Exploration Agency | And 2 more authors.
Measurement Science and Technology | Year: 2012

A spectral emissivity measurement system combined with an electrostatic levitator was developed for high-temperature melts. The radiation intensity from a high-temperature sample was measured with a multichannel photospectrometer (MCPD) over the 700-1000 nm spectral range, while a Fourier transform infrared spectrometer (FTIR) measured the radiation over the 1.1-6 m interval. These spectrometers were calibrated with a blackbody radiation furnace, and the spectral hemispherical emissivity was calculated. The system's capability was evaluated with molten zirconium samples. The spectral hemispherical emissivity of molten zirconium showed a negative wavelength dependence and an almost constant variation over the 1850-2210 K temperature range. The total hemispherical emissivity of zirconium calculated by integrating the spectral hemispherical emissivity was found to be around 0.32, which showed good agreement with the literature values. The constant pressure heat capacity of molten zirconium at melting temperature was calculated to be 40.9 J mol -1 K-1. © 2012 IOP Publishing Ltd.

Ishikawa T.,Japan Aerospace Exploration Agency | Paradis P.-F.,Japan Aerospace Exploration Agency | Okada J.T.,Japan Aerospace Exploration Agency | Watanabe Y.,Advanced Engineering Services Co.
Measurement Science and Technology | Year: 2012

Viscosities of several refractory metals (titanium, nickel, zirconium, niobium, ruthenium, rhodium, hafnium, iridium and platinum) and terbium have been measured by the oscillation drop method with an improved procedure. The measured data were less scattered than our previous measurements. Viscosities at their melting temperatures showed good agreement with literature values and some predicted values. © 2012 IOP Publishing Ltd.

Kinoshita K.,Japan Aerospace Exploration Agency | Miyata H.,Advanced Engineering Services Co. | Tanaka R.,Advanced Engineering Services Co. | Ueda T.,Japan Aerospace Exploration Agency | And 3 more authors.
Journal of Crystal Growth | Year: 2012

Compositionally uniform 10 mm diameter Si 0.5Ge 0.5 bulk crystals were grown by the traveling liquidus-zone (TLZ) method which we developed for the alloy crystal growth. Axial compositional variation was less than 0.5 at% for the length of 12 mm and radial one was less than 0.3 at% and showed excellent compositional uniformity. The average full width at half maximum of X-ray rocking curves for 004 diffraction measured across a disk is less than 36 arcsec (0.01°) at a distance of 3.5 mm away from the seed/crystal interface. This shows high crystallinity and promise of TLZ-grown crystals as substrates for CMOS devices using n-channels of strained Si thin films and p-channels of strained Ge thin films. © 2012 Elsevier B.V. All rights reserved.

Adachi S.,Japan Aerospace Exploration Agency | Kinoshita K.,Japan Aerospace Exploration Agency | Takayanagi M.,Japan Aerospace Exploration Agency | Miyata H.,Advanced Engineering Services Co.
Journal of Crystal Growth | Year: 2011

In order to investigate more suitable sample configurations for obtaining radially larger and more homogeneous compound semiconductor crystals, a two-dimensional model of the traveling liquidus-zone method is introduced. From numerical results of the model, it is found that inhomogeneity increases with the thermal conductivity of a crucible wall. This is mainly attributed to the heat flow slanted towards the crucible wall near an interface. The numerical results show, however, that the low thermal conductivity of the crucible does not sufficiently reduce the inhomogeneity, which is caused by the slanted heat flow. We also investigate the influence of a seed crystal. It is found that a seed crystal with large thermal conductivity is far more effective to improve the homogeneity. © 2011 Elsevier B.V. All rights reserved.

Tawara H.,High Energy Accelerator Research Organization | Masukawa M.,Japan Aerospace Exploration Agency | Nagamatsu A.,Japan Aerospace Exploration Agency | Kitajo K.,Advanced Engineering Services Co. | And 2 more authors.
Radiation Measurements | Year: 2011

A PAssive Dosimeter for Life-science Experiments in Space (PADLES) has been developed for measuring total absorbed dose and dose equivalents in the radiation environments of the International Space Station (ISS) where the Linear Energy Transfer (LET) of radiation ranges from 0.2 (ionization minimum) to 103 keVμm-1 or more. PADLES consists of two types of passive and integrating radiation detectors: MSO-S (Mg2SiO 4:Tb) ThermoLuminescence Dosimeters (TLDs) and antioxidant-doped CR-39 plastic nuclear track detectors. In this paper, we first describe a method to obtain a water-equivalent absorbed dose by combining data from these two types of detector. In order to increase the reliability of PADLES for ISS space radiation dosimetry, we investigated the following characteristics of MSO-S TLDs: calibration of our ThermoLuminescence (TL) readout system for high-energy protons and gamma rays from 60Co and 137Cs sources; dose responses for high-energy heavy ions (He, C, Si, Ar, Fe); response variation of different manufacture batches; directional response for the high-energy protons; the initial variations and long-term fading effects of the TL response for high-energy protons and heavy ions at temperatures from -80 °C to 60 °C; and LET response. © 2011 Elsevier Ltd. All rights reserved.

PubMed | Olympus Optical Co., Tohoku University, Chiyoda Corporation, Nagoya City University and 3 more.
Type: Journal Article | Journal: The Review of scientific instruments | Year: 2016

To clarify the growth mechanism of a protein crystal, it is essential to measure its growth rate with respect to the supersaturation. We developed a compartment (growth cell) for measuring the growth rate (<0.1 nm s(-1)) of the face of a protein crystal at a controlled supersaturation by interferometry over a period of half a year in space. The growth cell mainly consists of quartz glass, in which the growth solution and a seed crystal are enclosed by capillaries, the screw sample holder, and a helical insert. To avoid the destruction of the cell and the evaporation of the water from the solution inside the cell, we selected the materials for these components with care. The equipment was successfully used to examine the growth of a lysozyme crystal at a controlled supersaturation in space, where convection is negligible because of the microgravity environment, thereby advancing our understanding of the mechanism of protein crystal growth from solution. The technique used to develop the growth cell is useful not only for space experiments but also for kinetic studies of materials with very slow growth and dissolution rates (<10(-3) nm s(-1)).

Background: Group 1 introns (ribozymes) are among the most ancient and have the broadest phylogenetic distribution among the known self-splicing ribozymes. Fungi are known to be rich in rDNA group 1 introns. In the present study, five sequences of the 28S ribosomal RNA gene (rDNA) regions of pathogenic dematiaceous Phialophora verrucosa were analyzed using PCR by site-specific primers and were found to have three insertions, termed intron-F, G and H, at three positions of the gene. We investigated the distribution of group 1 introns in this fungus by surveying 34 strains of P. verrucosa and seven strains of Phialophora americana as the allied species. Results: Intron-F's (inserted at L798 position) were found in 88% of P. verrucosa strains, while intron-G's (inserted at L1921) at 12% and intron-H's (inserted at L2563) at 18%. There was some correlation between intron distribution and geographic location. In addition, we confirmed that the three kinds of introns are group 1 introns from results of BLAST search, alignment analysis and Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). Prediction of secondary structures and phylogenetic analysis of intron sequences identified introns-F and G as belonging to subgroup IC1. In addition, intron-H was identified as IE. Conclusion: The three intron insertions and their insertion position in the 28S rDNA allowed the characterization of the clinical and environmental isolates of P. verrucosa and P. americana into five genotypes. All subgroups of introns-F and G and intron-H were characterized and observed for the first time in both species. © 2011 Takizawa et al; licensee BioMed Central Ltd.

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