Search results for " Spheroid"

Electronic-structure-induced deformations of liquid metal clusters

1995

Ab initio molecular dynamics is used to study deformations of sodium clusters at temperatures $500\cdots 1100$ K. Open-shell Na$_{14}$ cluster has two shape isomers, prolate and oblate, in the liquid state. The deformation is stabilized by opening a gap at the Fermi level. The closed-shell Na$_8$ remains magic also at the liquid state.

Investigation of E0 Transition in 74Kr

2000

The N = Z+2 nucleus 74Kr has been investigated by in-beam conversion electron (CE) and γ ray spectroscopy. The electric-monopole (E0) decay was examined in order to confirm the evidence for a low-lying isomeric 0+2 state and to give insight into the mixing between the predicted coexisting prolate and oblate shapes.

Influence of growth, measuring conditions, and cell types on oxygen tensions in multicell tumor spheroids determined by microelectrodes

1981

Investigation on the pollen morphology of traditional cultivars of Prunus species in Sicily

2012

In this study pollen grains of 13 cultivars and 3 rootstocks belonging to 5 species (<em>P. armeniaca</em>, <em>P. domestica</em>, <em>P. dulcis</em>, <em>P. persica</em>, <em>P. avium</em>) of the genus <em>Prunus </em>collected from North-East Sicily were examined for the micromorphological characterization through the scanning electron microscopy (SEM). The length of polar axis (<em>P</em>) and the equatorial diameter (<em>E</em>) of grain, <em>P/E </em>ratio, the length of colpi (<em>C</em>), diameter of perforations (<em>DP</em>) and the number of perforat…

3.3 Glucose levels in microregions of multicellular EMT6/Ro tumor spheroids

1991

Potential and energy of oblate spheroidal charge distributions

1989

Abstract The Poisson equation for a large class of charge distributions contained within oblate spheroids in solved and their energies are obtained. In many cases, the potential and the energy can be found by comparison with the solutions of the Poisson equation for prolate spheroidal charge distributions obtained in preceding works. The limits of validity of this comparison procedure are established. For the simplest cases the electrostatic energy is computed and, after suitable normalization, displayed graphically.

Search for dark matter from the Galactic halo with the IceCube neutrino telescope

2011

Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large-scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of ⟨σAv⟩≃10-22 cm3 s-1 for weakly interacting massive particle masses above 1 TeV, assuming a monochromatic neutrino line spectrum.

A systematic study of hidden sector dark matter: application to the gamma-ray and antiproton excesses

2020

In hidden sector models, dark matter does not directly couple to the particle content of the Standard Model, strongly suppressing rates at direct detection experiments, while still allowing for large signals from annihilation. In this paper, we conduct an extensive study of hidden sector dark matter, covering a wide range of dark matter spins, mediator spins, interaction diagrams, and annihilation final states, in each case determining whether the annihilations are s-wave (thus enabling efficient annihilation in the universe today). We then go on to consider a variety of portal interactions that allow the hidden sector annihilation products to decay into the Standard Model. We broadly class…

Low-spin excitations in the 109Tc nucleus

2012

Monoisotopic samples of ${}^{109}$Mo nuclei, produced in the deuteron-induced fission of ${}^{238}$U and separated using the IGISOL mass separator coupled to a Penning trap, were used to perform $\ensuremath{\beta}$- and $\ensuremath{\gamma}$-coincidence spectroscopy of ${}^{109}$Tc. Spin and parity 5/2${}^{+}$ for the ground state of ${}^{109}$Mo, proposed earlier, are supported in the present work. Three new low-energy levels observed in ${}^{109}$Tc are interpreted as bandheads of the $\ensuremath{\pi}3/{2}^{\ensuremath{-}}$[301], $\ensuremath{\pi}5/{2}^{\ensuremath{-}}$[303], and $\ensuremath{\pi}1/{2}^{+}$[431] configurations, respectively. A further three levels observed around 0.4 Me…

Lifetimes of intruder states in 186Pb, 188Pb and 194Po

2008

Abstract Lifetimes of prolate intruder states in 186Pb and 188Pb and oblate intruder states in 194Po have been determined through recoil distance Doppler-shift lifetime measurements. Deformation parameters of | β 2 | = 0.29 ( 5 ) and | β 2 | = 0.17(3) have been extracted from experimental B ( E 2 ) values for the prolate and the oblate bands, respectively. The present study addresses the phenomenon of shape coexistence typical for the nuclei near Z = 82 and N = 104 , providing information on configuration mixing of intrinsic structures of the nuclei of interest. The results are compared with the available lifetime data and theoretical results for neutron-deficient Po, Pb, Hg and Pt nuclei. …