2,491 research outputs found

    Self-consistency in the Projected Shell Model

    Full text link
    The Projected Shell Model is a shell model theory built up over a deformed BCS mean field. Ground state and excited bands in even-even nuclei are obtained through diagonalization of a pairing plus quadrupole Hamiltonian in an angular momentum projected 0-, 2-, and 4-quasiparticle basis. The residual quadrupole-quadrupole interaction strength is fixed self-consistently with the deformed mean field and the pairing constants are the same used in constructing the quasiparticle basis. Taking 160Dy^{160}Dy as an example, we calculate low-lying states and compare them with experimental data. We exhibit the effect of changing the residual interaction strengths on the spectra. It is clearly seen that there are many Jπ=0+,1+,4+J^\pi = 0^+, 1^+, 4^+ bandheads whose energies can only be reproduced using the self-consistent strengths. It is thus concluded that the Projected Shell Model is a model essentially with no free parameters.Comment: 13 pages, 10 figures, submitted to Nuclear Physics

    Backbending in Dy isotopes within the Projected Shell Model

    Get PDF
    A systematic study of the yrast band in 154-164 Dy isotopes using the Projected Shell Model is presented. It is shown that, in the context of the present model, enlarging the mean field deformation by about 20 % allows a very good description of the spectrum of yrast band in these isotopes. The dependence of the B(E2) values on angular momentum is also better described when larger deformations are used. The observed oscillation of g-factors at low spin states remains an open question for this model.Comment: 17 pages, 7 figures, submitted to Phys. Rev.

    Neutron/proton ratio of nucleon emissions as a probe of neutron skin

    Full text link
    The dependence between neutron-to-proton yield ratio (RnpR_{np}) and neutron skin thickness (δnp\delta_{np}) in neutron-rich projectile induced reactions is investigated within the framework of the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model. The density distribution of the Droplet model is embedded in the initialization of the neutron and proton densities in the present IQMD model. By adjusting the diffuseness parameter of neutron density in the Droplet model for the projectile, the relationship between the neutron skin thickness and the corresponding RnpR_{np} in the collisions is obtained. The results show strong linear correlation between RnpR_{np} and δnp\delta_{np} for neutron-rich Ca and Ni isotopes. It is suggested that RnpR_{np} may be used as an experimental observable to extract δnp\delta_{np} for neutron-rich nuclei, which is very significant to the study of the nuclear structure of exotic nuclei and the equation of state (EOS) of asymmetric nuclear matter.Comment: 7 pages, 5 figures; accepted by Phys. Lett.

    c-Axis tunneling in YBa2Cu3O7-\delta/PrBa2Cu3O7-\delta superlattices

    Full text link
    In this work we report c-axis conductance measurements done on a superlattice based on a stack of 2 layers YBa2Cu3O{7-\delta} and 7 layers PrBa2Cu3O{7-\delta} (2:7). We find that these quasi-2D structures show no clear superconducting coupling along the c-axis. Instead, we observe tunneling with a gap of \Delta_c=5.0\pm 0.5 meV for the direction perpendicular to the superconducting planes. The conductance spectrum show well defined quasi-periodic structures which are attributed to the superlattice structure. From this data we deduce a low temperature c-axis coherence length of \xi_c=0.24\pm 0.03 nm.Comment: 15 pages, 5 figures. To appear in Phys.Rev.

    Synthesis of deuterium‐labelled amlexanox and its metabolic stability against mouse, rat, and human microsomes

    Full text link
    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149374/1/jlcr3716_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149374/2/jlcr3716.pd

    Assessment of grape cluster yield components based on 3D descriptors using stereo vision

    Full text link
    NOTICE: this is the author’s version of a work that was accepted for publication in Food Control. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Control, [Volume 50, April 2015, Pages 273–282] DOI 10.1016/j.foodcont.2014.09.004Wine quality depends mostly on the features of the grapes it is made from. Cluster and berry morphology are key factors in determining grape and wine quality. However, current practices for grapevine quality estimation require time-consuming destructive analysis or largely subjective judgment by experts. The purpose of this paper is to propose a three-dimensional computer vision approach to assessing grape yield components based on new 3D descriptors. To achieve this, firstly a partial three-dimensional model of the grapevine cluster is extracted using stereo vision. After that a number of grapevine quality components are predicted using SVM models based on new 3D descriptors. Experiments confirm that this approach is capable of predicting the main cluster yield components, which are related to quality, such as cluster compactness and berry size (R2 > 0.80, p < 0.05). In addition, other yield components: cluster volume, total berry weight and number of berries, were also estimated using SVM models, obtaining prediction R2 of 0.82, 0.83 and 0.71, respectively.This work has been partially funded by the Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria de Espana (INIA - Spanish National Institute for Agriculture and Food Research and Technology) through research project RTA2012-00062-C04-02, support of European FEDER funds, UPV-SP20120276 and AGL2011-23673 project.Ivorra Martínez, E.; Sánchez Salmerón, AJ.; Camarasa Baixauli, JG.; Diago, M.; Tardaguila, J. (2015). Assessment of grape cluster yield components based on 3D descriptors using stereo vision. Food Control. 50:273-282. https://doi.org/10.1016/j.foodcont.2014.09.004S2732825

    Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-

    Full text link
    We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi --> D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7 J/Psi events collected with the BESII detector at the BEPC. No excess of signal above background is observed, and 90% confidence level upper limits on the branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi --> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure

    precision control of the electron longitudinal bunch shape using an emittence-exchange beam line

    Get PDF
    We report on the experimental generation of relativistic electron bunches with a tunable longitudinal bunch shape. A longitudinal bunch-shaping (LBS) beam line, consisting of a transverse mask followed by a transverse-to-longitudinal emittance exchange (EEX) beam line, is used to tailor the longitudinal bunch shape (or current profile) of the electron bunch. The mask shapes the bunch&apos;s horizontal profile, and the EEX beam line converts it to a corresponding longitudinal profile. The Argonne wakefield accelerator rf photoinjector delivers electron bunches into a LBS beam line to generate a variety of longitudinal bunch shapes. The quality of the longitudinal bunch shape is limited by various perturbations in the exchange process. We develop a simple method, based on the incident slope of the bunch, to significantly suppress the perturbations.1162Ysciescopu

    Bound Chains of Tilted Dipoles in Layered Systems

    Full text link
    Ultracold polar molecules in multilayered systems have been experimentally realized very recently. While experiments study these systems almost exclusively through their chemical reactivity, the outlook for creating and manipulating exotic few- and many-body physics in dipolar systems is fascinating. Here we concentrate on few-body states in a multilayered setup. We exploit the geometry of the interlayer potential to calculate the two- and three-body chains with one molecule in each layer. The focus is on dipoles that are aligned at some angle with respect to the layer planes by means of an external eletric field. The binding energy and the spatial structure of the bound states are studied in several different ways using analytical approaches. The results are compared to stochastic variational calculations and very good agreement is found. We conclude that approximations based on harmonic oscillator potentials are accurate even for tilted dipoles when the geometry of the potential landscape is taken into account.Comment: 10 pages, 6 figures. Submitted to Few-body Systems special issue on Critical Stability, revised versio

    Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar

    Full text link
    The branching ratios and Angular distributions for J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure
    corecore