2,484 research outputs found

    On the Radii of Brown Dwarfs Measured with AKARI Near-Infrared Spectroscopy

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    We derive the radii of 16 brown dwarfs observed by AKARI using their parallaxes and the ratios of observed to model fluxes. We find that the brown dwarf radius ranges between 0.64-1.13 RJ with an average radius of 0.83 RJ. We find a trend in the relation between radii and Teff; the radius is at a minimum at Teff~1600 K, which corresponds to the spectral types of mid-to late-L. The result is interpreted by a combination of radius-mass and radius-age relations that are theoretically expected for brown dwarfs older than 10^8 yr.Comment: 22 pages, 3 figures; submitted 2012 October 14 and accepted 2013 February 12 for publication to The Astrophysical Journa

    Terahertz Waveform Measurements Using a Chirped Optical Pulse and Terahertz Spectroscopy of Reverse Micellar Solution: Towards Time-resolved Terahertz Spectroscopy of Protein in Water

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    One challenging research target using terahertz spectroscopy is time-resolved terahertz spectroscopy of protein molecules to clarify the relationship between protein’s functions and the low-frequency collective motion within the molecule. Our results on two research topics necessary for this target are described. One is single-shot measurements of terahertz waveform that has large advantages in time-resolved terahertz spectroscopy. We examined experimentally and theoretically single-shot measurements using chirped optical pulses. The other is terahertz spectroscopy of reverse micellar solutions in which nanometer-sized water droplets are formed. Protein powder is usually used as a sample for terahertz spectroscopy because the absorption of terahertz waves by solvent water is very strong in aqueous solutions of protein, although protein molecules work in water. The absorption of terahertz waves by the nonpolar oil solvent in reverse micellar solution is considerably weak compared with that by water. We demonstrated that terahertz absorption spectra of protein in liquids are obtained by the use of protein-containing reverse micellar solution. On the other hand, a nanometer-sized water droplet in reverse micellar solutions is a promising candidate for studies of supercooled water. We made temperature-dependent terahertz spectroscopy of the water droplet to study collective water motions due to hydrogen bond networks

    Continuing Adequate Squat Exercise without Load for Selfcare in the Difficult Circumstances Worldwide

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    Across the world, Coronavirus disease 2019 (COVID-19) has been crucial medical and social problem. People have continued irregular meal and exercise habits. Fundamental factors of exercise prescription are FITT-VP, which stand for frequency, intensity, time, type, volume and progression. Authors continued various physiotherapeutic activities such as treatment, workshop, self-care and so on. Among them, squat exercise with no load would be useful and beneficial method in current situation. In order to perform the correct and smooth movement of squat exercise, to insert the both thumbs into anterior side of the hip joint will be recommended for obtaining clinical efficacy

    Forward Leaning and Two Axis Operation for Effective and Safe Running

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    The players have felt the swaying of the gravity center and smooth running without sports injuries. As a future prospect, Masters Athletes encouraged to acquire more flexibility of the body trunk and to improve the interlocking of the body. Consequently, further progress will be expected to make evolution for better running using the power of the gravity

    X-Ray Reflection Nebulae with Large Equivalent Widths of Neutral Iron Ka Line in the Sgr C Region

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    This paper reports on the first results of the Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4keV, Ka from neutral or low-ionized Fe. One of them, M359.38-0.00, is newly discovered with Suzaku. The X-ray spectra of the two bright clumps, M359.43-0.07 and M359.47-0.15, after subtracting the Galactic center diffuse X-ray emission (GCDX), exhibit strong Ka line from FeI with large equivalent widths (EWs) of 2.0-2.2keV and clear Kb of FeI. The GCDX in the Sgr C region is composed of the 6.4keV- and 6.7keV-associated components. These are phenomenologically decomposed by taking relations between EWs of the 6.4keV and 6.7keV lines. Then the former EWs against the associated continuum in the bright clump regions are estimated to be 2.4(+2.3_-0.7)keV. Since the two different approaches give similar large EWs of 2keV, we strongly suggest that the 6.4keV clumps in the Sgr C region are due to X-ray reflection/fluorescence (the X-ray reflection nebulae).Comment: Accepted for publication in PAS

    Growth of Antiperovskite Oxide Ca3SnO Films by Pulsed Laser Deposition

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    We report the epitaxial growth of Ca3SnO antiperovskite oxide films on (001)-oriented cubic yttria-stabilized zirconia (YSZ) substrates by using a conventional pulsed laser deposition (PLD) technique. In this work, a sintered Ca3SnO pellet is used as the ablation target. X-ray diffraction measurements demonstrate the (001) growth of Ca3SnO films with the antiperovskite structure and a cube-on-cube orientation relationship to the YSZ substrate. The successful synthesis of the antiperovskite phase is further confirmed by x-ray photoemission spectroscopy. These results strongly suggest that antiperovskite-oxide films can be directly grown on substrates from the target material using a PLD technique
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