49,999 research outputs found

    Investigation of environmental change pattern in Japan. Classification of shorelines

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    There are no author-identified significant results in this report

    Investigation of environmental change pattern in Japan. Utilization of LANDSAT-2 data for fisheries

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    The author has identified the following significant results. MSS data provided extensive and simultaneous information about marine environmental conditions, such as the shift of the Kuroshio, fall and rise of coastal water mass, distribution of water masses, locations of vortex and current rips, exchanges of water between embayment and open ocean effluent rivers, fertility of plankton, red tide, pollution, etc

    Formation and structure of equatorial anticyclones caused by large scale cross equatorial flows determined by ATS-1 photographs

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    Atmospheric models for cross equatorial air mass flow and anticyclone formatio

    The central simple modules of Artinian Gorenstein algebras

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    Let A be a standard graded Artinian algebra over a field of characteristic zero and let z be a linear form in A. We define the central simple modules for each such pair (A, z). Assume that A is Gorenstein. Then we prove that A has the strong Lefschetz property if and only if there exists a linear form z in A such that all central simple modules of the pair (A,z) have the strong Lefschetz property. In the course of proof we need to extend the definition of the strong Lefschetz property to finite graded modules over graded Artinian algebra, which previously was defined only for standard graded Artinian algebras.Comment: 20 pages, To be published in Journal of Pure and Applied Algebr

    General pattern of the turbid water in the Seto-inland sea extracted from multispectral imageries by the LANDSAT-1 and 2

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    The author has identified the following significant results. Each distribution pattern of turbid water changes with the time in accordance with daily tides, seasonal variation of tides, and occasional rainfall. Two cases of successfully repeated LANDSAT observations for the same sea regions suggested a general pattern of turbid water could be extracted for each region. Photographic and digital processes were used to extract patterns of turbid water separately from the cloud and smog-layer in MSS 4, 5, and 7 imageries. A mosaic of image-masked imageries displays a general pattern of turbid water for almost the entire Seto Inland Sea. No such pattern was extracted for the Aki-Nada south of Hiroshima City where the water is fairly polluted, nor for the Iyo-Nada where the water is generally clearer than in other regions of the Seto Inland Sea

    Fermi Surface Reconstruction without Breakdown of Kondo Screening at Quantum Critical Point

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    Motivated by recent Hall-effect experiment in YbRh2_2Si2_2, we study ground state properties of a Kondo lattice model in a two-dimensional square lattice using variational Monte Carlo method. We show that there are two types of phase transition, antiferromagnetic transition and topological one (Fermi surface reconstruction). In a wide region of parameters, these two transitions occur simultaneously without the breakdown of Kondo screening, accompanied by a discontinuous change of the Hall coefficient. This result is consistent with the experiment and gives a novel theoretical picture for the quantum critical point in heavy fermion systems.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

    An infrared measurement of chemical desorption from interstellar ice analogues

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    In molecular clouds at temperatures as low as 10 K, all species except hydrogen and helium should be locked in the heterogeneous ice on dust grain surfaces. Nevertheless, astronomical observations have detected over 150 different species in the gas phase in these clouds. The mechanism by which molecules are released from the dust surface below thermal desorption temperatures to be detectable in the gas phase is crucial for understanding the chemical evolution in such cold clouds. Chemical desorption, caused by the excess energy of an exothermic reaction, was first proposed as a key molecular release mechanism almost 50 years ago. Chemical desorption can, in principle, take place at any temperature, even below the thermal desorption temperature. Therefore, astrochemical net- work models commonly include this process. Although there have been a few previous experimental efforts, no infrared measurement of the surface (which has a strong advantage to quantify chemical desorption) has been performed. Here, we report the first infrared in situ measurement of chemical desorption during the reactions H + H2S -> HS + H2 (reaction 1) and HS + H -> H2S (reaction 2), which are key to interstellar sulphur chemistry. The present study clearly demonstrates that chemical desorption is a more efficient process for releasing H2S into the gas phase than was previously believed. The obtained effective cross-section for chemical desorption indicates that the chemical desorption rate exceeds the photodesorption rate in typical interstellar environments

    Restoration of isotropy on fractals

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    We report a new type of restoration of macroscopic isotropy (homogenization) in fractals with microscopic anisotropy. The phenomenon is observed in various physical setups, including diffusions, random walks, resistor networks, and Gaussian field theories. The mechanism is unique in that it is absent in spaces with translational invariance, while universal in that it is observed in a wide class of fractals.Comment: 11 pages, REVTEX, 3 postscript figures. (Compressed and encoded figures archived by "figure" command). To appear in Physical Review Letter
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