187 research outputs found

    Photometry of OV Bootis at the 2017 Outburst

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    We present our photometric results of OV Boo obtained during the 2017 outburst

    レタス植物体中におけるクロロゲン酸含有量を増大させる明期延長型照明処理法の開発

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    科学研究費助成事業 研究成果報告書:基盤研究(C)2015-2017課題番号 : 15K0728

    Evaluation of water dynamics of contour-levee irrigation system in sloped rice fields in Colombia

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    Contour-levee irrigation system is commonly used for rice cultivation in Latin American and Caribbean countries, but its water dynamics in commercial farm field settings are yet to be fully determined. This study aimed to investigate the water dynamics of the contour-levee irrigation system by analyzing conventional irrigation practices and by quantifying water balance and additionally to examine potential toposequential effects. Field experiments with different irrigation intervals were conducted on three commercial farms in Ibagué, Colombia for two seasons from 2017 to 2018. Irrigation and runoff water flows were constantly measured during the crop cycle using Parshall flumes with water level sensors. Percolation rate and field water table were measured using percolators and piezometers installed along the toposequence. The results showed that conventional irrigation management was highly flexible depending on soil permeability, rainfall, and agronomic factors, not particularly paying attention to ensure the flooded conditions during flowering period. The water balance resulted in the irrigation accounting for 76% of the total water input, whereas the runoff, ET, and percolation accounted for 40%, 21%, and 31% on overall average with considerable variation among the three farms. Percolation rates and duration with standing water did not show a clear and consistent tendency among the toposequential positions, but the percolation rate was significantly different among the farms corresponding to soil permeability. Consequently, clear toposequential effects on the water dynamics or on grain yield were not observed at the study site. To our knowledge, this study is the first to elucidate detailed water dynamics of contour-levee irrigation system in farm fields including toposequential difference

    Interferometric Observations of the T Tauri Stars in the MBM 12 Cloud

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    We have carried out a millimeter interferometric continuum survey toward 7 YSOs in the MBM 12 cloud. Thermal emissions associated with 2 YSOs were detected above the 3-σ\sigma level at 2.1 mm, and one also showed a 1.3 mm thermal emission. Another object was marginally detected at 2.1 mm. Spectral energy distributions of the YSOs are well fitted by a simple power-law disk model. Masses of the circumstellar disks are estimated to be an order of 0.05 M_{\sun}. The circumstellar disks in the MBM 12 cloud have properties in common with the disks in nearby star-forming regions, in terms of disk parameters such as a disk mass, as well as an infrared excess.Comment: 9 pages, 3 figures, accepted by ApJ Letter

    Ultrasensitive determination of pyrroloquinoline quinone in human plasma by HPLC with chemiluminescence detection using the redox cycle of quinone

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    A fast, accurate, and ultrasensitive high-performance liquid chromatography method with chemiluminescence detection (HPLC-CL) was optimized and validated for the determination of pyrroloquinoline quinone (PQQ) concentration in human plasma following solid-phase extraction (SPE). This method is based on the redox cycle of the reaction between PQQ and dithiothreitol, which generates reactive oxygen species that can be detected using luminol as a CL probe. The isocratic HPLC system comprised an ODS column and 4.0 mM tetra-n-butylammonium bromide in Tris-HNO3 buffer (pH 8.8; 50 mM)-acetonitrile (7:3, v/v) as mobile phase. A novel, rapid, and simple SPE method was also developed providing excellent %recovery (?95.2%) for PQQ from human plasma samples. The proposed method was linear over the range of 4.0?400 nmol/L plasma of PQQ with a lower detection limit (S/N=3) of 1.08 nmol/L plasma (0.27 nM). The method was successfully implemented to determine PQQ concentration in the plasma of healthy individuals after administration of PQQ supplements

    Periodical structure of vortices in a semiconductor single wafer spin cleaner

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    We experimentally and numerically investigated large-scale structures formed by vortices in a single wafer spin cleaner. The Q-criterion identified the vortices developed in the cleaner as the flow regions with positive second invariant of the velocity gradient tensor obtained by both the PIV and LES. The time-series two-components PIV data shows that small-vortices were clustered near and under the edge of the rotating disk and were periodically emanated from there to the housing wall of the cleaner. The emanation frequency was increased with increasing in the angular velocity of the rotating disk. Three-dimensional LES reveal that six longitudinal vortices were spirally developed from under the edge of the rotating disk to the housing wall. This structure stably rotated slower than the disk speed. Fourier analysis of the LES data agreed with that of the PIV data. This supports that the passages of the stable spiral vortices on the PIV measurement region resulted in the periodical emanation of the clustered small-vortices observed in the PIV. Such a very large-scale spiral structure will induce reattachment of contaminants on the wafer surface, and should be destructed for development of much higher efficient cleaner
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