[en] We are developing a Compton telescope based on high resolution Si and CdTe imaging devices in order to obtain a high sensitivity astrophysical observation in sub-MeV gamma-ray region. In this paper, recent results from the prototype Si/CdTe semiconductor Compton telescope are reported. The Compton telescope consists of a double-sided Si strip detector (DSSD) and CdTe pixel detectors, combined with low noise analog LSI, VA32TA. With this detector, we obtained Compton reconstructed images and spectra from line gamma-rays ranging from 81 keV up to 356 keV. The energy resolution is 3.8 keV and 7.9 keV at 122 keV and 356 keV, respectively, and the angular resolution is 9.9^o and 5.7^o at 122 keV and 356 keV, respectively

[en] In this work, it is shown that RF voltages are induced along the sides of the Faraday shields of ICRF (ion cyclotron range of frequency) antennas and that these voltages cause modifications of plasma parameters and impurity production in the edge regions of fusion research plasmas. Specifically, in-air measurements with a capacitive probe on a model antenna and a Phaedrus-T two-strap antenna showed that RF voltages were induced along the sides of the Faraday shield when the sides were slotted. RF B field measurements with a B dot probe suggested that these voltages were induced primarily by the currents on the radial feeds of the antennas. RF-induced modifications of edge plasma parameters were found along the field lines that mapped to the Faraday shield in both the Phaedrus-B tandem mirror and the Phaedrus-T tokamak. In Phaedrus-T, when capacitive coupling between the edge plasma and the induced voltage was prevented by the attachment of boron nitride (an electric insulator) plates to the sides of the Faraday shield, both the RF-induced modifications of the edge plasma and the impurity production during ICRF were found to be greatly reduced

[en] I present an exact calculation of the most general supersymmetric amplitudes for K⁰ - K⁰ and B⁰ - B⁰ mixing resulting from gluino box diagrams. I use these amplitudes to place general constraints on the magnitude of off-generational, flavor-changing mass mixings in the squark mass matrices (with arbitrary chirality structures) that can arise both in and beyond the minimial supersymmetric Standard Model (MSSM). I use the renormalization group equations to estimate these mass mixings in the MSSM and in non-minimal supersymmetric models in terms of a general parameterization of universal soft supersymmetry breaking. I show that while these mass mixings are too small in the MSSM to yield an observable effects, the converse is true in most non-trivial extensions of the MSSM, including supersymmetric GUTs. In non-minimal supersymmetry, the K_L - K_S mass difference in sensitive to such contributions from supersymmetric particles with masses up to 100 TeV (20 TeV for the B_L = B_S mass difference), and the CP impurity parameter ε_K is sensitive to particle masses up to 1000 TeV. I show that supersymmetric CP violation can be predominantly 'superweak' (i.e, contribute mainly to ε_K) or 'milliweak' (ε') depending on the chirality of the off-generational squark mass mixings. The rare decay b → sγ is less sensitive that the aforementioned constraints, but probes somewhat different squark mass mixings. The lepton number violating decay μ → eγ is very sensitive to off-generational slepton mixing for sleptons up to TeV. All these processes provide valuable information regarding the structure of physics beyond the MSSM pertaining to arbitrarily high mass scales, including the nature of supersymmetry breaking

[en] It is well known that the terrestrial marine sediments have large cerium anomaly on their chondrite-normalized REE pattern. Siliceous shale and calcaleous sediments have negative Ce-anomaly. Ferromanganese nodule have positive or negative Ce-anomaly. The Ce-anomaly is considered to be a result of tetravalent state of cerium rather than common trivalent. Ferromanganese nodule which formed under reducing condition has negative Ce-anomaly. Then, combined study of Ce-anomaly with Ce isotopes is expected to play an important role in geochemistry. La-138 decays to Ce-138 and Ba-138 with a total half life of about 1 x 10 to the 11th years. Cerium anomalies (positive or negative) are expected in Martian paleo-ocean and in sediments as observed in the terrestrial environment. A list of things to be examined is given

[en] Respiratory motion artifacts are the main hazard of body MR imaging. The simplest way of suppressing respiratory motion artifacts is to acquire imaging data during suspended respiration. The authors have developed a new method of body MR imaging that diminishes respiratory motion artifacts by acquiring data during suspended respiration. The method, which is called ''pause scanning,'' can be used with any MR imaging pulse sequences. A Toshiba superconducting (0.5-T) magnet MR imaging unit was used. Using two-dimensional Fourier transform techniques, they divided one scan into several segments by setting the pause time. The phase-encoding gradient was set to be stable during the pause. Each segment of a total scan is composed of several projections and can be acquired during suspended respiration. The duration of imaging of each segment and of the pause can be changed at will. Pause imaging was compared with conventional imaging in ten healthy volunteers. The respiratory motion artifacts were minimized in all normal images

[en] Introduction of long term cycle of LWR reactor operation at NPP in Japan is considered, and problems of technical, legislative and economical character, increase of power coefficient are discussed. More long term operation period provides decreasing frequency of periodic inspections and reduction of personnel radiation doses. Reliability of fuel, energetic equipment, mechanisms and devices must be taken into account for the decision of technical problems. Consumptions for electric power generation are studied

[en] Complete text of publication follows. In this paper, a new substorm model which overcomes the difficulty of present current wedge model is developed from the analysis of numerical substorm obtained from the global MHD simulation. In the current wedge model, the region 1 field-aligned current (FAC) that causes the first brightening is the diverted cross-tail current due to the flow from the near earth neutral line (NENL). However, a well known difficulty for this model is the fact that a sudden brightening starts in the most equatorward preexisting arc without any perturbation in poleward arcs. In the present model, the onset is triggered by the abrupt formation of high-pressure region in the inner magnetosphere. This high-pressure region results from the magnetic tension released from the NENL, and intensifies the partial ring current. The tail disturbance is primary transmitted to the ionosphere by the region 2 FAC which is generated together with the partial ring current through the conversion of thermal energy to electromagnetic energy by convection crossing the high-pressure region. Since the ionospheric closure of region 2 FAC by midnight eastward current is equivalent to the dusk to dawn electric field that interrupt the convection, the closure of substorm region 2 FAC occurs by connecting with the newly developed nightside region 1 FAC, forming a grand loop. This connection with the region 1 FAC takes place through the nearest (most equatorward) arc. Associated nightside region 1 FAC does not connected to the traditional current wedge but to the cusp region.

[en] Complete text of publication follows. The convection and current system generating the substorm are investigated by analyzing the numerical solution obtained from the recent refined magnetohydrodynamic simulation. The present solution reproduces the observed signatures of substorm onset quite well, including a formation of the near earth neutral line (NENL), earthward flow in the plasma sheet, the dipolarization, the geosynchronous D deflection, a development of the nightside field aligned currents (FACs), and electrojets in the ionosphere. After the NENL formation, a rapid change appears in background convection to bring about transient magnetospheric compression that extends as far as the geosynchronous orbit. The compression results in the formation of high pressure in the ring current region. A primary driver of the substorm current is the partial ring current and incidental region 2 FAC which are generated by the high pressure and convection crossing it. Inertial current due to the braking of fast flow from the NENL does not generate the FAC. Inside the ionosphere, the region 2 FAC is not closed by midnight eastward ionospheric current, since it is equivalent to the dusk to dawn electric field which interrupts the convection. Alternatively, the region 2 FAC is closed by connecting with the nightside region 1 FAC from the cusp, forming a grand loop. The present model explains the longstanding question concerning the position of first brightening arc, because the region 2 FAC is expected to connect with the region 1 FAC through the nearest preexisting arc that is the most equatorward arc.

[en] HTGR steam generator tube welds with circumferential cracks in their highest stress region were assessed by linear elastic fracture mechanics methods. The computed stress intensity factors were below the threshold level for propagation and crack propagation will not occur for the pipe geometry (radius and thickness of tube wall) and the stress levels considered. In addition crack arrest may be expected if the predominant stress field is a thermally induced bending stress field

[en] The APWR development program was initiated as a part of the third phase of Improvement and Standardization Program for LWRs to improve the availability and economy for the future nuclear power plants in Japan. The major design objectives of the development program are as follows: (1) improved availability, (2) improved nuclear power economics, (3) improved operational performance, (4) improved plant safety, (5) reduction of radioactive waste and occupational radiation exposure, (6) efficient use of plant sites, and (7) conservation of resources. The major features of the APWR described emphasizes improvements in the nuclear steam supply system, fuel assembly, steam generator, fluid systems, and instrumentation and control systems, all of which have been modified significantly when compared with these of conventional PWRs