187 research outputs found

    Enhancing the Superconducting Transition Temperature due to Strong-Coupling Effect under Antiferromagnetic Spin Fluctuations in CeRh1-xIrxIn5 : 115In-NQR Study

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    We report on systematic evolutions of antiferromagnetic (AFM) spin fluctuations and unconventional superconductivity (SC) in heavy-fermion (HF) compounds CeRh1x_{1-x}Irx_{x}In5_5 via 115^{115}In nuclear-quadrupole-resonance (NQR) experiment. The measurements of nuclear spin-lattice relaxation rate 1/T11/T_1 have revealed the marked development of AFM spin fluctuations as a consequence of approaching an AFM ordered state with increasing Rh content. Concomitantly the superconducting transition temperature TcT_{\rm c} and the energy gap Δ0\Delta_0 increase drastically from Tc=0.4T_{\rm c} = 0.4 K and 2Δ0/kBTc=52\Delta_0/k_{\rm B}T_{\rm c} = 5 in CeIrIn5_5 up to Tc=1.2T_{\rm c} = 1.2 K and 2Δ0/kBTc=8.32\Delta_0/k_{\rm B}T_{\rm c} = 8.3 in CeRh0.3_{0.3}Ir0.7_{0.7}In5_5, respectively. The present work suggests that the AFM spin fluctuations in close proximity to the AFM quantum critical point are indeed responsible for the onset of strong-coupling unconventional SC with the line node in the gap function in HF compounds.Comment: 4pages,5figures,to appear in Phys. Rev. Let

    The role of a conserved guanosine residue in the hammerhead-type RNA enzyme

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    AbstractWe have designed a hammerhead-type RNA system which consists of three RNA fagments for normal and modified complexes which contain a non-cleavable substrate with 2'-O-methylcytidine and a guanosine-to-inosine replaced enzyme. Examination of the RNA-cleaving activity and conformational properties of the complexes suggests that the 2-amino group of a conserved guanosine residue in the loop region plays an important role for maintaining both the activity and loop conformation

    Oxygen Isotope Exchange Between Molten Silicate Spherules and Ambient Water Vapor with Nonzero Relative Velocity: Implication for Chondrule Formation Environment

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    Oxygen isotope compositions of chondrules reflect the environment of chondrule formation and its spatial and temporal variations. Here, we present a theoretical model of oxygen isotope exchange reaction between molten silicate spherules and ambient water vapor with finite relative velocity. We found a new phenomenon, that is, mass-dependent fractionation caused by isotope exchange with ambient vapor moving with nonzero relative velocity. We also discussed the plausible condition for chondrule formation from the point of view of oxygen isotope compositions. Our findings indicate that the relative velocity between chondrules and ambient vapor would be lower than several 100 m/s when chondrules crystallized.Comment: 15 pages, 8 figures. Accepted for publication in Icaru

    How to evaluate science problem solving in a computerized learning environment? Construction of an analyzing scheme

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    Περιέχει το πλήρες κείμενοThis paper describes the construction of a ‘computerized science problem solving’ scheme, which enables analysis and evaluation of the effectiveness of science problem-solving by junior high-school students working in a computerized learning environment. The scheme was based on observations of 187 students as they solved qualitative science problems taken from a specific computerized learning environment. Students were also interviewed before and after the problem solving. The scheme is presented on two levels. The large-scale comprises 11 main categories, each sub-divided into sub-categories to yield the detailed-level. The sub-categories were based on a repertoire of activities found in the observation protocols, and were approved by external judgement and a validation process. The detailed-level scheme enables evaluation and statistical analysis of the participants' problem-solving effectiveness, providing substantial evidence for the construct validity of the scheme, and demonstrating its potential as a valid analyzing and evaluative tool for computerized science problem solving

    Effect of Nitriding parameter on Active Screen Plasma Nitriding Response of SACM645 Steel

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    A nitriding steel SACM645 was active screen plasma nitrided using an austenitic stainless steel screen to investigate the effect of nitriding parameters such as gas pressure and the distance between the screen and the sample on the nitriding response. The sample was treated for 18 ks at 823 K in 25% N2 + 75% H2. The gas pressure was changed to 100, 600, and 1200 Pa. The distance between the screen and the sample was also changed to 10, 30, and 50 mm. The nitrided samples were characterized by observing their surface morphology and cross sectional microstructure by scanning electron microscopy, X ray diffraction, and microhardness testing. After nitriding, polygonal particles with a normal distribution were observed at the center and edges of all nitrided sample surfaces. The particles on the sample surface became finer with an increase in the gas pressure. A nitrided layer with a greater and homogeneous thickness was obtained at a low gas pressure of 100 Pa

    Applicability of radiocolloids, blue dyes and fluorescent indocyanine green to sentinel node biopsy in melanoma

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    Patients with primary cutaneous melanoma underwent sentinel node (SN) mapping and biopsy at 25 facilities in Japan by the combination of radiocolloid with gamma probe and dye. Technetium-99m (99mTc)-tin colloid, 99mTc-phytate, 2% patent blue violet (PBV) and 0.4% indigo carmine were used as tracers. In some hospitals, 0.5% fluorescent indocyanine green, which allows visualization of the SN with an infrared camera, was concomitantly used and examined. A total of 673 patients were enrolled, and 562 cases were eligible. The detection rates of SN were 95.5% (147/154) with the combination of tin colloid and PBV, 98.9% (368/372) with the combination of phytate and PBV, and 97.2% (35/36) with the combination of tin colloid or phytate and indigo carmine. SN was not detected in 12 cases by the combination method, and the primary tumor was in the head and neck in six of those 12 cases. In eight of 526 cases (1.5%), SN was detected by PBV but not by radiocolloid. There were 13 cases (2.5%) in which SN was detected by radiocolloid but not by PBV. In 18 of 36 cases (50%), SN was detected by radiocolloid but not by indigo carmine. Concomitantly used fluorescent indocyanine green detected SN in all of 67 cases. Interference with transcutaneous oximetry by PVB was observed in some cases, although it caused no clinical trouble. Allergic reactions were not reported with any of the tracers. 99mTc-tin colloid, 99mTc-phytate, PBV and indocyanine green are useful tracers for SN mapping.ArticleJOURNAL OF DERMATOLOGY. 39(4):336-338 (2012)journal articl

    Seismic reflection survey using Vibroseis in Zama city and Hiratsuka city, Kanto basin, central Japan

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    Seismic reflection survey using Vibroseis with a line length of 13km was conducted around Zama city and Hiratsuka city, in the southwest part of the Kanto basin. Seismic refraction records were also acquired by shooting at the both ends of the survey line with over 100 vertical stacks. From the seismic section, a clear reflector interpreted as the top of the acoustic basement is identified. The basement has a very complex structure with depths varying from 200m to 1200 m. As a result of a refraction method analysis, the P-wave velocity of the basement is estimated to be about 4.3 km/s. Comparing acoustic logging data of Atsugi observation well, it corresponds to the lower part of the Aikawa Group (Miocene volcanics). The interpreted basement has a different velocity and geology from that commonly observed in the Kanto plain (4.8-5.5 km/s layer). Above the basement, sediments can be divided into two parts by a remarkable reflector seen at depths of 200 300m at both ends of the line. As this reflector has a velocity of 2.3-2.4 km/s, this corresponds to the boundary between the Sagami Group (Quaternary sediments) and the Aikawa Group observed at the Atsugi well. The Sagami Group contains sharp and continuous reflectors with flat or gentle dips, whereas the upper part of the Aikawa Group is accompanied with considerable folds and faults

    Recent comparability of oceanographic nutrients data: Results of a 2003 intercomparison exercise using reference materials

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    An intercomparison exercise was conducted using the recently developed Reference Material for Nutrients in Seawater (RMNS). Discrepancies of reported values among laboratories were greater than the homogeneity of RMNS samples and the reported analytical precision of nutrients. The variability of in-house standards of the participating laboratories might be the most likely source of interlaboratory discrepancies. Therefore, the use of common reference materials, i.e. certified RM, is essential to establish and improve the comparability of nutrient data of the world's oceans
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