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T. Gaitanos C. Fuchs H.H. Wolter A. Faessler 《The European Physical Journal A - Hadrons and Nuclei》2001,12(4):421-433
We investigate differential in-plane and out-of-plane flow observables in heavy-ion reactions at intermediate energies from
0.2-2 AGeV within the framework of relativistic BUU transport calculations. The mean field is based on microscopic Dirac-Brueckner-Hartree-Fock
(DB) calculations. We apply two different sets of DB predictions, those of ter Haar and Malfliet and more recent ones from
the Tübingen group, which are similar in general but differ in details. The latter DB calculations exclude spurious contributions
from the negative-energy sector to the mean field which results in a slightly softer equation of state and a less repulsive
momentum dependence of the nucleon-nucleus potential at high densities and high momenta. For the application to heavy-ion
collisions in both cases non-equilibrium features of the phase space are taken into account on the level of the effective
interaction. The systematic comparison to experimental data favours the less repulsive and softer model. Relative to non-relativistic
approaches one obtains larger values of the effective nucleon mass. This produces a sufficient amount of repulsion to describe
the differential flow data reasonably well.
Received: 8 January 2001 / Accepted: 12 November 2001 相似文献
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TN Ruckmongathan 《Pramana》1999,53(1):199-212
Liquid crystal displays had a humble beginning with wrist watches in the seventies. Continued research and development in
this multi-disciplinary field have resulted in displays with increased size and complexity. After three decades of growth
in performance, LCDs now offer a formidable challenge to the cathode ray tubes (CRT).
A major contribution to the growth of LCD technology has come from the developments in addressing techniques used for driving
matrix LCDs. There are several approaches like passive matrix addressing, active matrix addressing and plasma addressing to
drive a matrix display.
Passive matrix LCD has a simple construction and uses the intrinsic non-linear characteristic of the LCD for driving. Departure
from conventional line by line addressing of a passive matrix has resulted in improved performance of the display. Orthogonal
functions have played a crucial role in the development of passive matrix addressing. Simple orthogonal functions that are
useful for driving a matrix LCD are introduced. The basics of driving several rows simultaneously (multi-line addressing)
are discussed by drawing analogies from multiplexing in communication. The impact of multi-line addressing techniques on the
performance of the passive matrix LCDs in comparison with the conventional technique will be discussed. 相似文献
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MAO Feng SHI YiPeng XUAN LiJun SU WeiDong & WU JieZhi State Key Laboratory for Turbulence Complex Systems College of Engineering Peking University Beijing China University of Tennessee Space Institute Tullahoma TN USA 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decompos... 相似文献
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Singh AJ Razzak M Teesdale-Spittle P Gaitanos TN Wilmes A Paterson I Goodman JM Miller JH Northcote PT 《Organic & biomolecular chemistry》2011,9(12):4456-4466
Two new peloruside congeners (3 and 4) were isolated from wild and aquacultured collections of the New Zealand marine sponge Mycale hentscheli. Small-scale reactions on peloruside A (1) have been performed, which along with the isolation of 3 and 4, give further insight into the bioactive pharmacophore of 1. 相似文献
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M. Di Toro V. Baran M. Colonna T. Gaitanos V. Greco Liu Bo S. Plumari V. Prassa J. Rizzo H.H. Wolter 《Progress in Particle and Nuclear Physics》2009,62(2):389-401
Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. In this report, we present a selection of new reaction observables in dissipative collisions particularly sensitive to the symmetry term of the nuclear Equation of State (Iso-EoS). We will first discuss the Isospin Equilibration Dynamics. At low energies, this manifests via the recently observed Dynamical Dipole Radiation, due to a collective neutron-proton oscillation, with the symmetry term acting as a restoring force. At higher beam energies, Iso-EoS effects will be seen in Imbalance Ratio Measurements, in particular from the correlations with the total kinetic energy loss. For fragmentation reactions in central events, we suggest to look at the coupling between isospin distillation and radial flow. In Neck Fragmentation reactions, important Iso-EoS information can be obtained from the correlation between isospin content and alignment. The high density symmetry term can be probed from isospin effects on heavy ion reactions at relativistic energies (few AGeV range). Rather, isospin sensitive observables are proposed from nucleon/cluster emissions, collective flows and meson production. The possibility to shed light on the controversial neutron/proton effective mass splitting in asymmetric matter is also suggested. A large symmetry repulsion at high baryon density will also lead to an “earlier” hadron-deconfinement transition in n-rich matter. A suitable treatment of the isovector interaction in the partonic EoS appears very relevant. 相似文献
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We show that in collisions with neutron-rich heavy ions at energies around the production threshold K0 and K+ yields probe the isospin-dependent part of the nuclear equation of state at high baryon densities. In particular, we suggest the K0/K+ ratio as a promising observable. Results obtained in a covariant relativistic transport approach are presented for Au+Au collisions at 0.8-1.8A GeV. The focus is put on the equation of state influence which goes beyond the collision-cascade picture. The isovector part of the in-medium interaction affects the kaon multiplicities via two mechanisms: (i) a symmetry potential effect, i.e., a larger neutron repulsion in n-rich systems, and (ii) a threshold effect, due to the change in the self-energies of the particles involved in inelastic processes. Genuine relativistic contributions are revealed that could allow one to directly "measure" the Lorentz structure of the effective isovector interaction. 相似文献
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H.H. Wolter V. Prassa T. Gaitanos M. Di Toro V. Greco 《Progress in Particle and Nuclear Physics》2009,62(2):402-406
The nuclear symmetry energy as a function of density is rather poorly constrained theoretically and experimentally both below saturation density, but particularly at high density, where very few relevant experimental data exist. We discuss observables which could yield information on this question, in particular, proton-neutron flow differences, and the production of pions and kaons in relativistic heavy ion collisions. For the meson production we investigate particularly ratios of the corresponding isospin partners π−/π+ and K0/K+, where we find that the kaons are an interesting probe to the symmetry energy. In this case we also discuss the influence of various choices for the kaon potentials or in-medium effective masses. 相似文献
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The formation of fragments in proton-induced reactions at low relativistic energies within a combination of a covariant dynamical transport model and a statistical approach is investigated. In particular, we discuss in detail the applicability and limitations of such a hybrid model by comparing data on fragmentation at low relativistic SIS/GSI-energies. 相似文献
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V. Prassa T. Gaitanos G. Ferini M. Di Toro G.A. Lalazissis H.H. Wolter 《Nuclear Physics A》2010,832(1-2):88-99
Kaon properties are studied within the framework of a fully covariant transport approach. The kaon–nucleon potential is evaluated in two schemes, a chiral perturbative approach and an effective One-Boson-Exchange model. Isospin effects are explicitly accounted for in both models. The transport calculations indicate a significant sensitivity of momentum distributions and total yields of isospin states on the choice of the kaon–nucleon interaction. Furthermore, isospin effects are rather moderate on absolute kaon yields, but appear on strangeness ratios. This is an important issue in determining the high density symmetry energy from studies of strangeness production in heavy-ion collisions. 相似文献
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