[en] The existence of hadron-rich families associated with few gamma-ray emissions, named Centauro and Mini-Centauro phemonena was reported. It was investigated whether these are produced by a special type of interaction different from the ordinary pion multiple production. The experimental results are compared with calculations based on an ordinary multiple pion production model. Both hadron multiplicity distribution, obtained from the present observation and the calculation, show almost the same distribution which means that hadron bundles of such smaller multiplicities are considered to originate from successive interactions of surviving nucleons with the nature of multiple production during passage through the atmosphere

[en] There are many types of screens to be used in diagnostic examinations. It is well known that the different types of screens cause the different values of scatter fraction because the fluorescent material has Κ-edge and scattered photon energy spectra are shifted to lower side from primary ones. The authors devised a practical calculation method to estimate the scatter fraction even if using any type of screen. Energy shift of scattered photons is evaluated with the Clein-Nishina formula of compton scattering. Calculation values agree within 20% deviation from measured ones

[en] To design high-temperature materials with suitable ductility and high strength at high temperatures, Ir-Pt-Al alloys were investigated. It is expected that precipitation hardening by the B2 phase and solid-solution hardening of Ir by Pt and Al occur in the Ir-Pt-Al alloys. The phase constitution and microstructure were investigated by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and electron probe microscopy analysis (EPMA). Compression creep tests were then carried out with some of these alloys at 1773 K under 30 MPa. The creep mechanism is discussed in terms of the microstructure and phase constituents. Finally, the potential of Ir-Pt-Al alloys as high-temperature materials is discussed

[en] To design high-temperature materials with good creep properties at 1773 K, the creep behavior of Ir-Ni-Al alloys was investigated. The phase constitution and microstructure of the Ir-Ni-Al alloys were examined using X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). Compression creep tests were then carried out with some of the Ir-Ni-Al alloys at 1773 K under 30 MPa. The deformation mechanism was discussed in terms of solid-solution hardening and precipitation hardening

[en] Arrangements of pancake vortices in Bi₂Sr₂CaCu₂O_8+y are studied by means of the Bitter decoration in the presence of dense Josephson vortices. Vortex chains are visualized in in-plane fields up to 1000 Oe. Increase of out-of-plane fields up to 33 G smears the vortex chains. This smearing is quantitatively in reasonable agreement with a theoretically predicted transition from chain + lattice to deformed lattice state

[en] We studied vortex states in Bi₂Sr₂CaCu₂O_8+y under tilted fields by means of Bitter decoration. The results in large in-plane fields up to 3000 Oe show zigzag arrangement of vortices in addition to the chains. A possible origin of this novel arrangement of vortices is discussed

No abstract available

[en] A Fermi surface study of the ferromagnetic phase of CeSb is presented. The γ frequency branches arising from the electron surfaces at the X points, three separate frequency branches from the hole surfaces at the GAMMA point and the low frequency branch α have been observed. The effective mass ratios are low and range from approx. 0.2 for the α branch to approx. 1.0 for the high frequency branch of γ. The low effective mass ratios suggest that the admixture of the conduction states with the f state is small. We have observed a drastic change in the appearance of the dHvA signal at the phase transition between the ferromagnetic and lower field antiferromagnetic phases: The low frequency α oscillation suddenly disappears as the crystal enters the antiferromagnetic phase. By utilizing the change in the signal appearance, the transition field strength has been measured as a function of the field direction. The present experimental results, particularly the origin of the α oscillation, are discussed in the light of the p-f mixing theory and recent band structure calculations based on localized f orbitals

[en] Eighteen degree sector test apparatus (ESTA), which mocks up BWR plant, has been constructed and refill-reflood phenomena during LOCA conditions have been studied. The objective of this study is to confirm the conservatism of current safety evaluation models and to present the data base for best estimate code qualification and verification. ESTA is full height from jet pump bottom to standpipe top and main components within shroud are cut into an 18⁰ sector

[en] This paper describes analytical results of BWR upper plenum behavior under LOCA using TRAC-BDl code and comparison with ESTA (Eighteen Degree Sector Test Apparatus) results. TRAC-BDl is a best estimate system code and features a three dimensional treatment of the BWR pressure vessel and a one dimensional treatment of fuel bundles and pipings. ESTA is the BWR LOCA refill-reflood test facility which mocks up an 18 degrees sector of the BWR with full height from jet pump bottom to standpipe top. The objective of this study is to verify the predictive capability of the TRAC-BDl code through the analysis of ESTA saturated CCFL tests with special emphasis on multi-dimensional nonequilibrium two phase flow behavior