2,987 research outputs found

    Distribution of Snow and Maximum Snow Water Equivalent Obtained by LANDSAT Data and Degree Day Method

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    Maximum snow water equivalence and snowcover distribution are estimated using several LANDSAT data taken in snowmelting season over a four year period. The test site is Okutadami-gawa Basin located in the central position of Tohoku-Kanto-Chubu District. The year to year normalization for snowmelt volume computation on the snow line is conducted by year to year correction of degree days using the snowcover percentage within the test basin obtained from LANDSAT data. The maximum snow water equivalent map in the test basin is generated based on the normalized snowmelt volume on the snow line extracted from four LANDSAT data taken in a different year. The snowcover distribution on an arbitrary day in snowmelting of 1982 is estimated from the maximum snow water equivalent map. The estimated snowcover is compared with the snowcover area extracted from NOAA-AVHRR data taken on the same day. The applicability of the snow estimation using LANDSAT data is discussed

    Correlated Emission of Hadrons from Recombination of Correlated Partons

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    We discuss different sources of hadron correlations in relativistic heavy ion collisions. We show that correlations among partons in a quasi-thermal medium can lead to the correlated emission of hadrons by quark recombination and argue that this mechanism offers a plausible explanation for the dihadron correlations in the few GeV/c momentum range observed in Au+Au collisions at RHIC.Comment: 4 pages, 2 figures; v2: typo on p.4 correcte

    Pressure Tuning of an Ionic Insulator into a Heavy Electron Metal: An Infrared Study of YbS

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    Optical conductivity [σ(ω)\sigma(\omega)] of YbS has been measured under pressure up to 20 GPa. Below 8 GPa, σ(ω)\sigma(\omega) is low since YbS is an insulator with an energy gap between fully occupied 4ff state and unoccupied conduction (cc) band. Above 8 GPa, however, σ(ω)\sigma(\omega) increases dramatically, developing a Drude component due to heavy carriers and characteristic infrared peaks. It is shown that increasing pressure has caused an energy overlap and hybridization between the cc band and 4ff state, thus driving the initially ionic and insulating YbS into a correlated metal with heavy carriers

    Kondo effect in CeXc_{c} (Xc_{c}=S, Se, Te) studied by electrical resistivity under high pressure

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    We have measured the electrical resistivity of cerium monochalcogenices, CeS, CeSe, and CeTe, under high pressures up to 8 GPa. Pressure dependences of the antiferromagnetic ordering temperature TNT_{N}, crystal field splitting, and the lnT\ln T anomaly of the Kondo effect have been studied to cover the whole region from the magnetic ordering regime at low pressure to the Fermi liquid regime at high pressure. TNT_{N} initially increases with increasing pressure, and starts to decrease at high pressure as expected from the Doniach's diagram. Simultaneously, the lnT\ln T behavior in the resistivity is enhanced, indicating the enhancement of the Kondo effect by pressure. It is also characteristic in CeXc_{c} that the crystal field splitting rapidly decreases at a common rate of 12.2-12.2 K/GPa. This leads to the increase in the degeneracy of the ff state and further enhancement of the Kondo effect. It is shown that the pressure dependent degeneracy of the ff state is a key factor to understand the pressure dependence of TNT_{N}, Kondo effect, magnetoresistance, and the peak structure in the temperature dependence of resistivity.Comment: 9 pages, 5 figures, accepted for publication in J. Phys. Soc. Jp

    Evaluation of Bearing Capacity of Friction Pile Based on Uncertainty of Soil Properties

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    The authors have proposed a method for evaluation of vertical bearing capacity of bored friction pile which might be capable to reflect the uncertainty of soil properties on the evaluation. The rationality of the method is examined from the application to the bridge design in this paper. A vertical bearing capacity of pile foundation is practically estimated by expressions with N-value, in which there are two kinds of uncertainties which depend on the N-values at the estimation points and the coefficient of the bearing capacity expressions. It is, therefore, necessary to improve the accuracy in estimating the bearing capacity that spatial distribution of N-values in the ground are predicted with a high accuracy and in-situ loading test results are reflected in the bearing capacity expressions

    Investigation of environmental change pattern in Japan

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    The author has identified the following significant results. A detailed land use classification for a large urban area of Tokyo was made using MSS digital data. It was found that residential, commercial, industrial, and wooded areas and grasslands can be successfully classified. A mesoscale vortex associated with large ocean current, Kuroshio, which is a rare phenomenon, was recognized visually through the analysis of MSS data. It was found that this vortex affects the effluent patterns of rivers. Lava flowing from Sakurajima Volcano was clearly classified for three major erruptions (1779, 1914, and 1946) using MSS data

    High pTp_T Measurements from PHENIX

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    We present recent high transverse momentum measurements by the PHENIX experiment for Au+Au and p+p collisions at sNN=200\sqrt{s_{NN}} = 200 GeV at the Relativistic Heavy Ion Collider (RHIC). We show particle spectra for neutral pions and charged hadrons, define and show the nuclear modification factor, and discuss particle composition. By means of the nuclear modification factor, we observe a suppression factor of 5-6 for neutral pions and 3-4 for charged hadrons in central collisions at high pTp_T. We find that the ratio of π0\pi^0 to (h++h)/2(h^++h^-)/2 remains nearly constant at 0.5\sim 0.5 for pT=29p_T = 2-9 GeV/c. Finally we present strong evidence for the observation of jets in Au+Au collisions.Comment: 10 pages, 11 figures, Talk presented at Quark Matter 2002, Nantes, France, July 18-24, 2002. To appear in the proceedings (Nucl. Phys. A

    High-Temperature Transport Properties of Yb4−xSmxSb3

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    Polycrystalline L4Sb3 (L = La, Ce, Sm, and Yb) and Yb4−x Sm x Sb3, which crystallizes in the anti-Th3P4 structure type (I-43d no. 220), were synthesized via high-temperature reaction. Structural and chemical characterization were performed by x-ray diffraction and electronic microscopy with energy-dispersive x-ray analysis. Pucks were densified by spark plasma sintering. Transport property measurements showed that these compounds are n-type with low Seebeck coefficients, except for Yb4Sb3, which shows semimetallic behavior with hole conduction above 523 K. By partially substituting Yb by a trivalent rare earth we successfully improved the thermoelectric figure of merit of Yb4Sb3 up to 0.7 at 1273 K
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