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NUMO and JAEA have been conducting a joint research since FY2011, which is aimedto enhance the methodology of repository design and performance assessment inpreliminary investigation stage for the deep geological disposal of high-levelradioactive waste. As a part of this joint research, we have been developingglass dissolution models which include various processes derived fromglass-overpack-bentonite buffer interaction, considering the precipitation ofFe-silicates associated with steel overpack corrosion, and Si transport throughaltered layer of glass. The objective of this modeling work is to showcomprehensively the lifetime of the vitrified waste due to glass matrixdissolution timescales through sensitivity analysis, and to identify thefeature/process that most strongly influences the lifetime, and to identifyfuture R&D issues that would help to improve the nuclide transportanalysis with confidential value and the safety case in future. The sensitivityanalysis suggested that the duration of the glass dissolution might be predictedin the ranges from 3.8×103 to 1.9×105years. Also, the results indicated that the precipitation ofFe–silicate has the strongest influence on the long-team behavior ofvitrified waste.
Two Norway rats, Rattus norvegicus, were found to be naturally infected with Echinococcus multilocularis in Japan. One of them was simultaneously infected with at least three different sized metacestodes of Taenia taeniaeformis. These two R. norvegicus rats and another R. norvegicus naturally infected with T. taeniaeformis and Capillaria hepatica were examined to see if they showed any antibody responses against these two cestode parasites with the view to obtaining more information on the importance of rats as the intermediate host for E. multilocularis. These R. norvegicus showed very poor antibody responses against the two cestode species, although the Wistar rats, R. rattus, experimentally infected with a single smaller sized metacestode of T. taeniaeformis showed stronger responses not only against T. taeniaeformis but also against E. multilocularis. Therefore the three R. norvegicus naturally infected with E. multilocularis and/or T. taeniaeformis demonstrated virtually no immune response, at least against these cestodes.
A novel stimulated trapped electron-acoustic wave scattering instability by a linearly polarized laser interacting with a subcritical density plasma layer is observed by particle simulation. Its spectrum in the early stage is well-explained by a resonant three-wave parametric decay process and it takes place whether the ion dynamics are taken into account or not. When ion dynamics are considered, the excitation of the ion electrostatic wave, the generation of the electromagnetic (EM) soliton and the formation of ion vortices due to the large EM soliton, etc., are studied.
Three-dimensional electrostatic particle simulations are performed in order to investigate the effects of ion flow parallel to magnetic-field lines and their velocity shears on low-frequency plasma instabilities in detail. In the case where the ion drift speed is so small that the low-frequency instabilities cannot take place, the ion-acoustic wave is destabilized by introducing the ion-flow velocity shear. The ion-acoustic wave is locally destabilized in the large velocity shear region. On the other hand, the ion-cyclotron instability is also destabilized when the ion drift speed exceeds a certain threshold. The flow velocity shear enhances not only the fundamental mode but also the high harmonic modes. As a result, the spiky fluctuations in the time domain are locally observed in the velocity shear region, which are caused by the simultaneous existence of several coherent ion-cyclotron harmonics.
A new and simple approach for stellarator edge modeling is presented. This is based on averaging of edge plasma parameters and introducing effective two-dimensional flux surfaces which allow us to use the UEDGE transport code, widely used for tokamak edge plasma modeling. This approach is applied to edge modeling of the Large Helical Device (LHD). It should be noted that our model is based on a two-dimensional configuration which is called the stellarator-equivalent tokamak (SET), while a stellarator system is inherently three-dimensional. Numerical simulations show that a bump of ion density in the private flux region just inside the separatrix appears, and flow reversal or a vortex structure of the ion flow is observed. Detailed analyses are necessary for validating this approach.
The mechanism of electron acceleration by intense laser pulse interacting with an underdense plasma layer is examined by one-dimensional particle-in-cell (1D-PIC) simulations. The standard dephasing limit and the electron acceleration process are discussed briefly. A new phenomenon, of short high-quality, well-collimated return relativistic electron beam with thermal energy spread, is observed in the direction opposite to laser propagation. The process of the electron beam formation, its characteristics, and the time-history in x and px space for test electrons in the beam, are analyzed and exposed clearly. Finally, an estimate for the maximum electron energy appears in a good agreement with simulation results.
InSb1-xNx was grown on GaAs substrate by low-pressure metalorganic vapor phase epitaxy. Carrier gases were hydrogen or the mix of hydrogen and nitrogen. In both cases, X-ray analysis demonstrated that nitrogen was incorporated into InSb1-xNx up to 0.24.
We attempted to detect the Earth-Moon libration clouds around L4 with a cooled CCD camera at Mauna Kea (4200m), Hawaii, on November 17 and 18, 1999. No significant enhancement of brightness larger than 1.5S10⊙ was found around L4. It seems that the brightness of the libration clouds in 1999, if it existed, would be fainter than that reported previously by Kordylewski and Roach.
The Lagrangian points L4 and L5 are the triangular solutions of the restricted three-body problem. The L4 is located in the leading side and the L5 in the trailing side of an orbit. In the solar system, it is widely known that certain asteroids called the “Trojan family” exist around the Sun-Jupiter Lagrangian points. It is also known that (5261) Eureka is a Mars Trojan. Kuchner et al. tried to find the dust clouds around the Sun-Jupiter L5 point by analysing the COBE-DIRBE infrared data, but they obtained a negative result.
Increases in height were reported in children chronically exposed prenatally and postnatally to D2 receptor-blocking drugs. A possible haplotypic association between stature and the DRD2 gene was also reported. In this study, we examined linkage between stature and DRD2 by genotyping a dinucleotide repeat polymorphism in 79 sib-pairs aged 8–17 years. An association between stature and a putative functional polymorphism in the promoter region of the DRD2 gene was examined in the sib-pairs and in 125 unrelated male adults. All the subjects were Japanese. Linkage (p = 0.004, SIBPAL) and an association (p = 0.009, paired t-test, in the sib-pairs; p = 0.006, ANOVA, in the adults) with stature were suggested. These findings indicate that DRD2 is one of the genes that contribute to heritability of stature.
We have made aperture synthesis observations of CS(2-1) emission using the Nobeyama Millimeter Array (NMA), and obtained ~ 2” × 3” (0.005 × 0.008 pc) resolution image to investigate the velocity structures of Orion-KL. We found not only well-known expanding doughnut but the expanding hemisphere in the Orion-KL hot core.
We have made aperture synthesis multifield observations of Orion Molecular Cloud-1 (OMC-1) in the CS (J=1-0) line using the Nobeyama Millimeter Array (NMA), and obtained 9” resolution maps over 10’ length. The OMC-1 ridge shows a wiggled structure. The position angle of whole the ridge is ~ 0° - 10°, but ~ 20° - 30°around the clumps. It is possible to make this structure by the magnetic field with a position angle of ~ 150°. We also found filamentary structures in the northwest of Orion-KL, with a length-width ratio of more than 25, which are made by the gas flow from Orion-KL.
We have made high resolution (2-5″) CO observations of seven IR luminous (LIR > 1011 LO) galaxies. They are Arp220, Mrk231, NGC6240, NGC6090, NGC695, Mrk331 and NGC828. We can resolve CO emission from all the galaxies but Mrk231 (figure 1).
We have made aperture synthesis maps toward the Orion-KL nebula in CS(1-0), CS(2-1) and 3mm continuum with the Nobeyama Millimeter Array (NMA). The CS(1-0) maps were obtained across the central 2′ region of the Orion-KL nebula. Our maps show the rotating disk around the KL nebula with the diameter of 0.3 pc and the mass of 25 M⊙. The disk clearly shows the Keplerian rotation, which indicates that the mass of the KL nebula is 100 — 150 M⊙. The shell structure around the molecular outflow is also found in CS(1-0) map. This structure also appears in CS(2-1) map.
From 3mm continuum map, we have found at least six continuum sources. One of them is f-f emission from the ultra-compact HII region around BN. Other sources are the dust clumps whose masses are estimated to be 1 — 4 M⊙. The distribution of the dust clumps shows clear anti-correlation with the 20 μm emissions. This indicates that the 20 μm emissions are obscured by these dust clumps.
We present our recent results of high spatial resolution(2″-6″) CO and 13CO(J=1−0) observations with the Nobeyama Millimeter Array(NMA). We observed the central (1-2 kpc) regions of nearby galaxies, IC342, Maffei2, and NGC6946 with 2″-4″ resolution (45-90 pc) in CO and 13CO, and the 3' region of M51 with 4″-6″ resolution (180-280 pc). We discuss the structures and kinematics of molecular gas in the central region of nearby late-type spiral galaxies, and in spiral arms, and discuss the trigger of star formation from viewpoints of galactic shock, gas fueling by bars.
We have made aperture synthesis maps of Orion-KL in NH3(1,1),(2,2) and CS(J=l-0) emissions using the Nobeyama Millimeter Array. Both NH3 and CS maps show new detailed structures that have not been recognized before. Two NH3 filaments in the size of ~0.45 pc x0.04 pc are found extending to the northwest direction of Orion-KL. These filaments are associated with the HH objects and the finger-like H2 emissions; they are probably formed through the interaction with high velocity, highly channeled winds from the KL region. The CS maps show, on the other hand, shell structures around IRc2 as well as the well-known rotating disk. These shells coincide with the two lobes of the shock-excited H2 emission, being interpreted as the shock-compressed shells of ambient molecular gas interacting with the outflow from IRc2.
The distribution of H2O masers in the Sgr B2 core was observed with a 2.5′×2.5′ wide field and with 540 km s−1 total velocity coverage by the Nobeyama Millimeter Array. Thirty-nine resolved maser spots were detected with a relative positional accuracy of 0.3″, which are clustered into four separate regions. In Sgr B2 north, the cluster lies at the edge of the continuum ridge. One of the maser spots shows strong and wide velocity-spread emission, suggesting it may correspond to a center of star forming activity. In Sgr B2 main, the strong maser spots are projected just on the face of a compact HII region, and are red-shifted relative to the central velocity of the HII region. There are two possibilities to interpret our results in Sgr B2 (M). One is that the H2O maser spots are distributed around the HII region and are infailing to the HII region. The other is that the H2O maser sources are associated with the cloud in the foreground of the HII region.
We have made aperture synthesis observations of CS(J=l-0, 2-1) and NH3(1,1) lines and 49, 98, and 110 GHz continuum in NGC2071-1RS with the Nobeyama Millimeter Array. Wfe have obtained maps of these lines and continuum maps with 2”. 7-20” resolution, ffe have found that dense molecular gas has a disk structure with a radial scale ranging 0.01 pc - 0.1 pc and has a ring-like structure with expanding motion at the central 5000 AU region. We also have found that there exists double dust continuum sources which are separated by 2500 AU in projection and are apparently located at the inner edges of the ring. Our observational results suggest that the disk of molecular gas has a central hole formed by wind and UV radiation from a central young stellar object, the central part is expanding, and that dust continuum emission comes from tangential parts of the shock compressed ring (r~1300 AU, M(H2)~ 21-34 Mo, and n(H2)~ 109) at the most inner side of the disk structure. The other possible model of the dust continuum sources is a binary system of self-luminous young stellar objects.
We report NH3 observations of the Sgr A complex region including Sgr A West and the 20 km/s and 50 km/s molecular clouds (M–0.13–0.08 and M–0.02–0.07) using the Nobeyama Millimeter Array and the 45m telescope. NH3(1,1) and (2,2) lines were simultaneously observed to estimate the kinetic temperature. Our results suggest strong interaction between the molecular clouds and the continuum sources in the Sgr A complex. The interaction with continuum sources might be an important factor in determining the physical conditions of molecular gas in the galactic center region.
CRL2688 is suggested to be one of the proto-planetary nebulae which are probably at a stage in which the central star is evolving from the red giant phase with rapid mass loss (Zuckerman 1978). The bipolar shape in both the optical and H2 emission indicates that a dense toroid of dust and gas obscures the star and surrounds the optical emission. The toroid is probably responsible for channelling the mass loss to the polar directions (Ney et al. 1975, Morris 1981, Beckwith et al. 1984). We present the results of mapping observations of CO (J = 1-0) emission from the expanding molecular envelope (Zuckerman et al. 1976, Lo et al. 1976, Knapp et al. 1982, Thronson et al. 1983) of the bipolar reflection nebula CRL2688 using the Nobeyama 45-m telescope with a 1.5″ resolution at a 7″.5 observing spacing.