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Sample records for kekka heisei 13-nendo

  1. ONR Far East Scientific Information Bulletin. Volume 14, Number 1. HEISEI, Achieving Universal Peace

    DTIC Science & Technology

    1989-03-01

    them. Box 1. The Thin Two-Dimensional Periodic Potential The time-independent Schroedinger equation for a particle of effective mass m in potential V...the sum E - E + E (Bl-2) x,y z The Schroedinger equation then separates as -A2 (Vx2 + Vy 2) B(x,y) A2 Vz2 W(z)2. ~ ) + V(x,y) - E - -___ -V(z) + E 2m B... Schroedinger equation (Equa- the same tunneling probabilities on both tion B1-1), falls off exponentially from the sides the device would be symmetric--the

  2. Instant snapshot of the internal structure of Unzen lava dome, Japan with airborne muography

    PubMed Central

    Tanaka, Hiroyuki K. M.

    2016-01-01

    An emerging elementary particle imaging technique called muography has increasingly been used to resolve the internal structures of volcanoes with a spatial resolution of less than 100 m. However, land-based muography requires several days at least to acquire satisfactory image contrast and thus, it has not been a practical tool to diagnose the erupting volcano in a real time manner. To address this issue, airborne muography was implemented for the first time, targeting Heisei-Shinzan lava dome of Unzen volcano, Japan. Obtained in 2.5 hours, the resultant image clearly showed the density contrast inside the dome, which is essential information to predict the magnitude of the dome collapse. Since airborne muography is not restricted by topographic conditions for apparatus placements, we anticipate that the technique is applicable to creating images of this type of lava dome evolution from various angles in real time. PMID:28008978

  3. Instant snapshot of the internal structure of Unzen lava dome, Japan with airborne muography

    NASA Astrophysics Data System (ADS)

    Tanaka, Hiroyuki K. M.

    2016-12-01

    An emerging elementary particle imaging technique called muography has increasingly been used to resolve the internal structures of volcanoes with a spatial resolution of less than 100 m. However, land-based muography requires several days at least to acquire satisfactory image contrast and thus, it has not been a practical tool to diagnose the erupting volcano in a real time manner. To address this issue, airborne muography was implemented for the first time, targeting Heisei-Shinzan lava dome of Unzen volcano, Japan. Obtained in 2.5 hours, the resultant image clearly showed the density contrast inside the dome, which is essential information to predict the magnitude of the dome collapse. Since airborne muography is not restricted by topographic conditions for apparatus placements, we anticipate that the technique is applicable to creating images of this type of lava dome evolution from various angles in real time.

  4. Crystal Mush History at the Unzen Volcanic Complex of Southwestern Japan, determined using U-series Zircon Geochronology

    NASA Astrophysics Data System (ADS)

    Murphy, B. S.; de Silva, S. L.; Takarada, S.; Schmitt, A. K.

    2014-12-01

    Crystal-rich (40-50 vol.-%) intermediate to silicic lava has been the primary eruptive product of several recent hazardous eruptions: Mt. Pinatubo, Philippines (1991), Soufriere Hills, Montserrat (1995-present), and Unzen, Japan (1990-1995). Despite this association with such devastating eruptions, the formation, timing, and evacuation of such magmas is not well understood: do such eruptions tap a long-lived, multi-cycle crystal mush, or, is it generated in a single magmatic cycle prior to eruption? We are exploring these questions at the Unzen Volcanic Complex, Nagasaki-ken, Japan where a 500 ka history of crystal-rich dacitic dome eruptions has built the Unzen Volcanic Complex. Previous studies (e.g. Nakamura, 1995) have demonstrated the role of mafic recharge in rejuvenating crystal mush a few months prior to the most recent eruptions, but the history of the mush is unknown. Preliminary U-Th/U-Pb in zircon geochronology from the most recent eruption (Heisei-Shinzan; 1990-1995) and the 1792 dome collapse lava (Tenguyama; erupted 4.1±0.8 ka) reveal a complex history of individual zircons. Unpolished rims from the 1990-1995 eruption range in age from ~24.6 to 180 ka, while interior ages (on polished grains) are older, ranging from 60 to 200 ka. Zircons from Tenguyama record unpolished rim model ages of ca. 21 to 90 ka and interior ages of 37 to 225 ka. Rim-interior age differences range from 24 to 122 ka and 6 to 180 ka for Heisei-Shinzan and Tenguyama, respectively. No model ages younger than 20 ka have so far been determined. This leads to the hypothesis that eruptions at Unzen are tapping a long-lived, multi-cycle mush of significant longevity. Acquisition of additional U-Th/U-Pb data, including trace elements from other Unzen domes ranging in age back to 440 ka, is underway to test this hypothesis and more tightly link volcanism with subsurface processes.

  5. Dynamical Evolution of Short Period Planets in the Multiple Systems during the Host-Stars Contraction to the Main Sequence

    NASA Astrophysics Data System (ADS)

    Nagasawa, M.; Lin, D. N. C.

    2005-05-01

    We study the dynamical evolution of short-period extrasolar planets orbiting young host stars with other eccentric planets. During the fast stages of planet formation, the host-stars are in pre-main sequence stage and are surrounded by protoplanetary disks. As the host-stars evolve onto to the main sequence, the disks are depleted and the stellar radii and the speed of rotation change. All these effects influence the evolution of the orbits of short-period planets. In addition, when the short period planets whose period is less than 6 days have large eccentricities, the tidal dissipation of energy during the circularization would induce interior heating, inflation, Roche lobe overflow, and ultimately mass losses. We study the necessary conditions for the survival of hot Jupiters including the potential of the evolving disk, the potential due to the flattening of the star produced by the increasing stellar rotation, and the post-Newtonian potential of the host star. We find that the short-period planets orbiting around young stellar objects whose spin periods are longer than a few days may be highly vulnerable to the dissipation of the disk and evolution of the stars. Based on these results, we suggest that fast rotators have more short-period planets in multiple systems than slow rotating stars. This work was partly performed while MN held a JSPS Postdoctoral Fellowship for Research Abroad (Heisei 14). This work is supported in part by NASA through grant NAG5-11779 to D. N. C. Lin.