4,904 research outputs found

    Nuclear Reactions: A Challenge for Few- and Many-Body Theory

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    A current interest in nuclear reactions, specifically with rare isotopes concentrates on their reaction with neutrons, in particular neutron capture. In order to facilitate reactions with neutrons one must use indirect methods using deuterons as beam or target of choice. For adding neutrons, the most common reaction is the (d,p) reaction, in which the deuteron breaks up and the neutron is captured by the nucleus. Those (d,p) reactions may be viewed as a three-body problem in a many-body context. This contribution reports on a feasibility study for describing phenomenological nucleon-nucleus optical potentials in momentum space in a separable form, so that they may be used for Faddeev calculations of (d,p) reactions.Comment: to appear in the Proceedings of HITES 2012: Conference on `Horizons of Innovative Theories, Experiments, and Supercomputing in Nuclear Physics', June 4-7, 2012, New Orleans, Louisian

    Estimation of Precautionary Demand by Financial Anxieties

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    Pioneering work of modelling financial anxieties was given by Kimura et al (1999) as psychological change of people due to financial shocks. Since they regressed financial position (easy or tight) by nonstationary interest rate, their results exhibit high peaks not only in financial crisis period of 1997 and 1998, but also in the bubble economy period of 1987 to 1989, which seems to be a spurious regression. Furthermore, defining financial anxieties as the conditional variance in TARCH model, one of estimated coefficients did not satisfy sign condition. We got rid of these difficulties by introducing a growth rate model, where a change of financial position (toward ''tight'') under a change of interest rate (toward ''fall'') is regarded as financial anxieties. Such anxieties are quantified by conditional variance of EGARCH model and shown to be stationary. Precautionary demand caused by financial anxieties is estimated in VEC model and it is shown that money adjusted by precautionary demand satisfies a long-run equilibrium relationship in the system (adjusted money, real GDP, interest rate) even in the interval 1980q1 to 2003q2.financial anxieties, precautionary demand, cointegration, EGARCH

    FE analysis on tube hydroforming of small diametr ZM21 magnesium alloy tube

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    Tube hydroforming (THF) is one of the plasticity processing methods. Tubular parts, for instance automotive components are expanded by forces such as internal pressure and axial compression in order to deform an objective shape. THF has less restriction on shape and size of workpieces owing to adopting the liquid tool. The demand of a small diameter magnesium alloy tubular parts have been increased for applying small medical and electronic devices. In this study, it was investigated that influence of process conditions such as processing temperature, internal pressure and axial feeding amount on formability of small diameter ZM21 magnesium alloy tube with outer diameter of 2.0mm and thickness of 0.20mm. Furthermore, the processing conditions for improving the formability of material in THF were examined. For prior evaluation of deformation characteristics in the warm THF of small diameter ZM21 magnesium alloy tube, a finite element (FE) simulation was conducted. The FE method (FEM) code was used LS-DYNA 3D for analysis of the FE model of the tube and the dies. The material characteristics were obtained by tensile test and fracture test. From FE analysis results, it was elucidated that effect of the processing temperature, the variable internal pressure and the axial feeding amount on deformation behavior. The formability of ZM21 magnesium alloy tube was improved by processing at 250 C. The difference of deformation characteristic between FE results and experimental results was compared. As the results, the processing condition which could improve the formability of ZM21 tube was clarified using this FE model. The effect of adding the straightening stage in the loading path after the preform on formability was investigated. The thinning of the wall thickness of the tube was inhibited by calibration after the axial feeding

    Transport criticality of the first-order Mott transition in a quasi-two-dimensional organic conductor, κ\kappa-(BEDT-TTF)2_{2}Cu[N(CN)2_{2}]Cl

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    An organic Mott insulator, κ\kappa-(BEDT-TTF)2_{2}Cu[N(CN)2_{2}]Cl, was investigated by resistance measurements under continuously controllable He gas pressure. The first-order Mott transition was demonstrated by observation of clear jump in the resistance variation against pressure. Its critical endpoint at 38 K is featured by vanishing of the resistive jump and critical divergence in pressure derivative of resistance, 1RRP|\frac{1}{R}\frac{\partial R}{\partial P}|, which are consistent with the prediction of the dynamical mean field theory and have phenomenological correspondence with the liquid-gas transition. The present results provide the experimental basis for physics of the Mott transition criticality.Comment: 4 pages, 5 figure

    NMR Evidence for Antiferromagnetic Transition in the Single-Component Molecular Conductor, [Au(tmdt)_{2}] at 110 K

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    We present the results of a ^{1}H NMR study of the single-component molecular conductor, [Au(tmdt)_{2}]. A steep increase in the NMR line width and a peak formation of the nuclear spin-lattice relaxation rate, 1/T_{1}, were observed at around 110 K. This behavior provides clear and microscopic evidences for a magnetic phase transition at considerably high temperature among organic conductors. The observed variation in 1/T_{1} with respect to temperature indicates the highly correlated nature of the metallic phase.Comment: 5pages, 6figures to be published in J. Phys. Soc. Jp

    Resonant inelastic x-ray scattering probes the electron-phonon coupling in the spin-liquid kappa-(BEDT-TTF)2Cu2(CN)3

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    Resonant inelastic x-ray scattering at the N K edge reveals clearly resolved harmonics of the anion plane vibrations in the kappa-(BEDT-TTF)2Cu2(CN)3 spin-liquid insulator. Tuning the incoming light energy at the K edge of two distinct N sites permits to excite different sets of phonon modes. Cyanide CN stretching mode is selected at the edge of the ordered N sites which are more strongly connected to the BEDT-TTF molecules, while positionally disordered N sites show multi-mode excitation. Combining measurements with calculations on an anion plane cluster permits to estimate the sitedependent electron-phonon coupling of the modes related to nitrogen excitation

    Initial exploratory investigations of some simple candidate management procedures for southern Bluefin tuna.

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    Simple constant proportion and target based empirical candidate management procedures are applied to the basic grid operating model and a low recruitment robustness test for SBT . The first two approaches , DMM1 and DMM2 , respectively use CPUE index data only, while DMM3 ad ds gene tagging data to the DMM2 approach. The key results are that the DMM2 target based approach substantially outperforms the constant proportion DMM1 one in terms of smoothness of the TAC trajectories, and that (at least as far as investigations have b een possible to date) the addition of gene tagging data offers little improvement to depletion statistics in instances where low recruitment has occurred . Performance under DMM2 is unusually good, but this approach still needs to be subjected to the other robustness tests, and further attempts need to be made to seek more improvement in performance when gene tagging data are used

    Inclusive K+K^+ and exclusive K+YK^+Y photoproduction on the deuteron: Λ\Lambda- and Σ\Sigma-threshold phenomena

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    Inclusive K+K^+ and exclusive K+YK^+Y photoproduction on the deuteron are investigated theoretically. Modern hyperon-nucleon forces and a recently updated kaon photoproduction operator for the γ+NK++Y\gamma +N\to K^++Y process are used. Sizable effects of the hyperon-nucleon final state interaction are found near the K+ΛNK^+\Lambda N and K+ΣNK^+\Sigma N thresholds in the inclusive reaction. Angular distributions for the exclusive process show clear YNYN final state interaction effects in certain kinematic regions. Precise data especially for the inclusive process around the K+ΣNK^+\Sigma N threshold would help to clarify the strength and property of the ΛNΣN\Lambda N-\Sigma N interaction.Comment: 14 pages, 10 figure
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