831 research outputs found

    SHORT CHARACTERIZATION OF PLANT SPECIES FROM CENTAUREA GENUS PRESENT IN ”AL. BELDIE” HERBARIUM FROM ”MARIN DRĂCEA” NATIONAL INSTITUTE FOR RESEARCH AND DEVELOPMENT IN FORESTRY - BUCHAREST

    Get PDF
    ”Al Beldie” herbarium from ”Marin Drăcea” National Institute for Research and Development in Forestry is an important herbarium with a significant role in the present research paper.This herbarium is ilisted in Index Herbaria and is composed of approximately 60.000 sheets with dried specimens of plants. From those 60.000 sheets, 71 belong to the genus Centaurea, with 19 species to be more precise. All of these species were collected by known personalities in the field of systematic botany, most of them being Romanian. The species were collected between 1855 and 1951 from the entire world, with a great majority from Romania. The aim of this article is to describe some species of Centaurea that are present in this herbarium. In this way it can be observed how important it is to collect, identify and preserve sheets with dried species in herbarium, given that these species of plants can be very hard to identify

    Large scale shell model calculations for odd-odd 58−62^{58-62}Mn isotopes

    Full text link
    Large scale shell model calculations have been carried out for odd-odd 58−62^{58-62}Mn isotopes in two different model spaces. First set of calculations have been carried out in full fp\it{fp} shell valence space with two recently derived fp\it{fp} shell interactions namely GXPF1A and KB3G treating 40^{40}Ca as core. The second set of calculations have been performed in fpg9/2{fpg_{9/2}} valence space with the fpgfpg interaction treating 48^{48}Ca as core and imposing a truncation by allowing up to a total of six particle excitations from the 0f7/2_{7/2} orbital to the upper fp\it{fp} orbitals for protons and from the upper fp\it{fp} orbitals to the 0g9/2_{9/2} orbital for neutron. For low-lying states in 58^{58}Mn, the KB3G and GXPF1A both predicts good results and for 60^{60}Mn, KB3G is much better than GXPF1A. For negative parity and high-spin positive parity states in both isotopes fpgfpg interaction is required. Experimental data on 62^{62}Mn is sparse and therefore it is not possible to make any definite conclusions. More experimental data on negative parity states is needed to ascertain the importance of 0g9/2_{9/2} and higher orbitals in neutron rich Mn isotopes.Comment: 5 pages, 4 figures, Submitted to Eur. Phys. J.

    Population of bound excited states in intermediate-energy fragmentation reactions

    Get PDF
    Fragmentation reactions with intermediate-energy heavy-ion beams exhibit a wide range of reaction mechanisms, ranging from direct reactions to statistical processes. We examine this transition by measuring the relative population of excited states in several sd-shell nuclei produced by fragmentation with the number of removed nucleons ranging from two to sixteen. The two-nucleon removal is consistent with a non-dissipative process whereas the removal of more than five nucleons appears to be mainly statistical.Comment: 5 pages, 6 figure

    Measurement of excited states in 40Si and evidence for weakening of the N=28 shell gap

    Get PDF
    Excited states in 40Si have been established by detecting gamma-rays coincident with inelastic scattering and nucleon removal reactions on a liquid hydrogen target. The low excitation energy, 986(5) keV, of the 2+[1] state provides evidence of a weakening in the N=28 shell closure in a neutron-rich nucleus devoid of deformation-driving proton collectivity.Comment: accepted for publication in PR

    Two-neutron knockout from neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si

    Get PDF
    Two-neutron knockout reactions from nuclei in the proximity of the proton dripline have been studied using intermediate-energy beams of neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si. The inclusive cross sections, and also the partial cross sections for the population of individual bound final states of the 32^{32}Ar, 28^{28}S and 24^{24}Si knockout residues, have been determined using the combination of particle and Îł\gamma-ray spectroscopy. Similar to the two-proton knockout mechanism on the neutron-rich side of the nuclear chart, these two-neutron removal reactions from already neutron-deficient nuclei are also shown to be consistent with a direct reaction mechanism.Comment: Phys. Rev. C, rapid communication, in pres

    Enhanced collectivity in 74Ni

    Get PDF
    The neutron-rich nucleus 74Ni was studied with inverse-kinematics inelastic proton scattering using a 74Ni radioactive beam incident on a liquid hydrogen targetat a center-of-mass energy of 80 MeV. From the measured de-excitation gamma-rays, the population of the first 2+ state was quantified. The angle-integrated excitation cross section was determined to be 14(4) mb. A deformation length of delta = 1.04(16) fm was extracted in comparison with distorted wave theory, which suggests that the enhancement of collectivity established for 70Ni continues up to 74Ni. A comparison with results of shell model and quasi-particle random phase approximation calculations indicates that the magic character of Z = 28 or N = 50 is weakened in 74Ni
    • 

    corecore