Spin-dependent observables in surrogate reactions

Observables emitted from various spin states in compound U nuclei are investigated to validate usefulness of the surrogate reaction method. It was found that energy spectrum of cascading $\gamma$-rays and their multiplicities, spectrum of evaporated neutrons, and mass-distribution of fission fragments show clear dependence on the spin of decaying nuclei. The present results indicate that they can be used to infer populated spin distributions which significantly affect the decay branching ratio of the compound system produced by the surrogate reactions

The Dual Meissner Effect and Magnetic Displacement Currents

The dual Meissner effect is observed without monopoles in quenched $SU (2)$ QCD with Landau gauge-fixing. Magnetic displacement currents which are time-dependent Abelian magnetic fields play a role of solenoidal currents squeezing Abelian electric fields. Monopoles are not always necessary to the dual Meissner effect. The squeezing of the electric flux means the dual London equation and the massiveness of the Abelian electric fields as an asymptotic field. The mass generation of the Abelian electric fields is related to a gluon condensate $\neq 0$ of mass dimension 2.Comment: 4 pages, 5 Postscript figures, title modified, some references added, minor changes made ; Accepted for publication in Phys.Rev.Let

Convergence of the Allen-Cahn equation with Neumann boundary conditions

We study a singular limit problem of the Allen-Cahn equation with Neumann boundary conditions and general initial data of uniformly bounded energy. We prove that the time-parametrized family of limit energy measures is Brakke's mean curvature flow with a generalized right angle condition on the boundary.Comment: 26 pages, 1 figur

A diagnostic study of waves on the tropopause

The spatial structure and phase velocity of tropopause disturbances localized around the subpolar jet in the Southern Hemisphere are investigated using 6-hourly European Centre for Medium-Range Weather Forecasts reanalysis data covering 15 yr (1979–93). The phase velocity and phase structure of the tropopause disturbances are in good agreement with those of an edge wave vertically trapped at the tropopause. However, the vertical distribution of the ratio of potential to kinetic energy exhibits maxima above and below the tropopause and a minimum around the tropopause, in contradiction to edge wave theory for which the ratio is unity throughout the troposphere and stratosphere. This difference in vertical structure between the observed tropopause disturbances and edge wave theory is attributed to the effects of a finite-depth tropopause together with the next-order corrections in Rossby number to quasigeostrophic dynamic

Abelian dominance and the dual Meissner effect in local unitary gauges in SU(2) gluodynamics

Performing highly precise Monte-Carlo simulations of SU(2) gluodynamics, we observe for the first time Abelian dominance in the confining part of the static potential in local unitary gauges such as the F12 gauge. We also study the flux-tube profile between the quark and antiquark in these local unitary gauges and find a clear signal of the dual Meissner effect. The Abelian electric field is found to be squeezed into a flux tube by the monopole supercurrent. This feature is the same as that observed in the non-local maximally Abelian gauge. These results suggest that the Abelian confinement scenario is gauge independent. Observing the important role of space-like monopoles in the Polyakov gauge also indicates that the monopoles defined on the lattice do not necessarily correspond to those proposed by 't Hooft in the context of Abelian projection.Comment: 4 pages, 7 figure

Particle Size Measurement of Reaction Product Aerosol of Sodium-Oxygen

A multi-level scenario simulation system as a safety infrastructure technology is required for design optimization, safety margin adjustment, and innovative technology developments of sodium-cooled fast reactor (SFR). In order to properly implement the Verification and Validation (V & V) of the simulation system, it is indispensable to ensure experimental database of sodium chemistry as specific SFR safety issue. In this study, measurement results of aerosols generated by sodium-oxygen reaction for sodium fire event were reported with the aim of clarifying the radiation heat transport phenomena in the reaction field. The sodium-oxygen counter-flow diffusion flame was formed one-dimensionally above the sodium pool by the reaction between sodium vapour and oxygen. Argon (Ar) including 2% oxygen were introduced to a liquid sodium pool (temperature: 820K) under the reduced pressure condition (0.05MPa). Ar guard flows were employed to stabilize the reaction. The reaction continued more than 600 seconds without any changes in terms of flame shape and position. Aerosol size was measured as a function of Z (the distance from the sodium pool surface) and r (the distance from the center of the sodium pool). Laser Induced Incandescence (LII) and the Mie scattering method using the different wavelength laser beams (405nm, 450nm, 520nm, 532nm, 638nm and 650nm) were employed to ensure the measurement accuracy. Aerosol sizes from several hundred nm to 1 μm were measured in this reaction field and the aerosol size increased toward the sodium pool. This stemmed largely from aerosol growth and polymerization because the flow rate decreased near the sodium pool. It was also confirmed that the size of aerosol measured by LII was in good agreement with the measurement using the Mie scattering method under the same conditions. The refractive index of the aerosol was also evaluated to be 1.42-0.5i

Effect of time-correlation of input patterns on the convergence of on-line learning

We studied the effects of time correlation of subsequent patterns on the convergence of on-line learning by a feedforward neural network with backpropagation algorithm. By using chaotic time series as sequences of correlated patterns, we found that the unexpected scaling of converging time with learning parameter emerges when time-correlated patterns accelerate learning process.Comment: 8 pages(Revtex), 5 figure

Vacuum type of SU(2) gluodynamics in maximally Abelian and Landau gauges

The vacuum type of SU(2) gluodynamics is studied using Monte-Carlo simulations in maximally Abelian (MA) gauge and in Landau (LA) gauge, where the dual Meissner effect is observed to work. The dual Meissner effect is characterized by the coherence and the penetration lengths. Correlations between Wilson loops and electric fields are evaluated in order to measure the penetration length in both gauges. The coherence length is shown to be fixed in the MA gauge from measurements of the monopole density around the static quark-antiquark pair. It is also shown numerically that a dimension 2 gluon operator A^+A^-(s) and the monopole density has a strong correlation as suggested theoretically. Such a correlation is observed also between the monopole density and A^2(s)= A^+A^-(s) + A^3A^3(s) condensate if the remaining U(1) gauge degree of freedom is fixed to U(1) Landau gauge (U1LA). The coherence length is determined numerically also from correlations between Wilson loops and A^+A^-(s) and A^2(s) in MA + U1LA gauge. Assuming that the same physics works in the LA gauge, we determine the coherence length from correlations between Wilson loops and A^2(s). Penetration lengths and coherence lengths in the two gauges are almost the same. The vacuum type of the confinement phase in both gauges is near to the border between the type 1 and the type 2 dual superconductors.Comment: 13 pages, 22 figures, RevTeX 4 styl

The ASCA Medium Sensitivity Survey (the GIS Catalog Project): Source Counts and Evidence for Emerging Population of Hard Sources

We present first results from the ASCA Medium Sensitivity Survey (AMSS; or the GIS catalog project). From the serendipitous fields amounting to 106 degE-2, we determined the Log N - Log S relations in the 0.7-7 keV and 2-10 keV bands with the best statistical accuracy obtained so far, over the flux range from 1 x 10E-11 to 5 x 10E-14 and 7 x 10E-14 erg sE-1 cmE-2, respectively. When the sources detected in the 0.7-7 keV band are divided into two subsamples with higher and lower spectral hardness, the former exhibits a significantly steeper slope than the latter at fluxes below ~10E-12 erg sE-1 cmE-2 (0.7-7 keV). The average spectrum of sources becomes continuously harder toward fainter fluxes, from a photon index of 2.1 in the 0.7-10 keV range at the flux of ~10E-11 to 1.6 at ~10E-13 erg sE-1 cmE-2 (0.7-7 keV). This is consistent with the comparison of source counts between the 2-10 keV and the 0.7-2 keV band, and solves the puzzle of their discrepancy reported previously. Our results demonstrate rapid emergence of hard X-ray sources with a decreasing flux from \~10E-12 to ~10E-13 erg sE-1 cmE-2 (2-10 keV).Comment: 10 pages, 3 figures (including 2 color figures). Accepted for publication in ApJ