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排序方式: 共有257条查询结果,搜索用时 15 毫秒
1.
We study the propagation of the light mesons σ,ω,ρ, and a0(980) in dense hadronic matter in an extended derivative scalar coupling model. Within the scheme proposed it is possible
to unambiguously define effective density-dependent couplings at the Lagrangian level. We first apply the model to study asymmetric
nuclear matter with fixed isospin asymmetry, and then we pay particular attention to hypermatter in β-equilibrium. The equation
of state and the potential contribution to the symmetry coefficient arising from the mean-field approximation are investigated.
Received: 16 October 2001 / Accepted: 10 January 2002 相似文献
2.
Prashanth Jaikumar 《Pramana》2006,67(5):937-949
We investigate the impact of magnetic fields on the electron distribution of the electrosphere of quark stars. For moderately
strong magnetic fields of B ∼ 1013 G, quantization effects are generally weak due to the large number density of electrons at surface, but can nevertheless
affect the photon emission properties of quark stars. We outline the main observational characteristics of quark stars as
determined by their surface emission, and briefly discuss their formation in explosive events termed as quark-novae, which
may be connected to the r-process. 相似文献
3.
4.
5.
The state of super-dense matter is essential for us to understand the nature of pulsars; however, non- perturbative quantum chromodynamics makes it very difficult to make direct calculations of the state of cold matter at realistic baryon number densities inside compact stars. Nevertheless, from an observational point of view, it is conjectured that pulsars could be made up of quark clusters since the strong coupling between quarks might render the quarks to be grouped in clusters. In this paper, we attempt to find an equation of state of condensed quark-cluster matter in a phenomenological way. Supposing that the quark-clusters could be analogized to inert gases, we apply here the corresponding-state approach to derive the equation of state of quark-cluster matter, as was similarly demonstrated for nuclear and neutron-star matter in the 1970s. According to the calculations that we have presented, the quark-cluster stars, which are composed of quark-cluster matter, could have a high maximum mass that is consistent with observations and, in turn, further observations of pulsar mass could also place a constraint on the properties of quark-cluster matter. We will also briefly discuss the melting heat during the solid-liquid phase conversion and its related astrophysical consequences. 相似文献
6.
Pavel A. Tikhonov Nataliya G. Vasilenko Marat O. Gallyamov Georgii V. Cherkaev Viktor G. Vasilev Nina V. Demchenko Mikhail I. Buzin Sergey G. Vasilev Aziz M. Muzafarov 《Molecules (Basel, Switzerland)》2021,26(11)
New multiarm stars have been synthesized based on polylithium derivatives of high-generation carbosilane dendrimers. In the synthesis of multiarm stars based on the eighth-generation dendrimer, steric hindrances were observed even during the synthesis of a polylithium initiator. Subsequently, this led to chain transfer reactions between growing arms, as well as other side effects. As a result, dense nanogel formations with a higher tendency of ordering than in classical objects of this type were isolated from the reaction mixture. The study of the rheology of multiarm stars based on sixth-generation dendrimers made it possible to determine the activation energies of viscous flow in these objects, which makes it possible to consider them as objects with a macromolecular nature and a reptation flow mechanism. 相似文献
7.
The effects of gravitomagnetic force
on plasma oscillations are investigated
using the kinetic theory of homogeneous electrically neutral plasma in the
absence of external electric or magnetic field. The random phase assumption is employed neglecting the thermal motion of the electrons with respect to a fixed ion background. It is found that the gravitomagnetic force reduces the characteristic frequency of the plasma thus enhancing the refractive index of the medium. The estimates for the predicted effects are given for a typical white dwarf, pulsar, and neutron star. 相似文献
8.
Based on the Dirac equation describing an electron moving in a uniform and cylindrically symmetric magnetic field which may be the result of the self-consistent mean field of the electrons themselves in a neutron star, we have obtained the eigen solutions and the orbital magnetic moments of electrons in which each eigen orbital can be calculated. From the eigen energy spectrum we find that the lowest energy level is the highly degenerate orbitals with the quantum numbers pZ=0, n=0, and m≥0. At the ground state, the electrons fill the lowest eigen states to form many Landau magnetic cells and each cell is a circular disk with the radius λfree and the thickness λe, where λfree is the electron mean free path determined by Coulomb cross section and electron density and λe is the electron Compton wavelength. The magnetic moment of each cell and the number of cells in the neutron star are calculated, from which the total magnetic moment and magnetic field of the neutron star can be calculated. The results are compared with the observational data and the agreement is reasonable. 相似文献
9.
WANG Bo LIU ZhengWei HAN YunKun LEI ZhenXin LUO YangPing & HAN ZhanWen National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming China Key Laboratory for the Structure Evolution of Celestial Objects Graduate University of Chinese Academy of Sciences Beijing 《中国科学:物理学 力学 天文学(英文版)》2010,(3)
Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the progenitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different progenitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those infe... 相似文献
10.
Z.?Simic M.?S.?DimitrijevicEmail author L.?C.?Popovic M.?D.?Dacic 《Journal of Applied Spectroscopy》2005,72(3):443-446
Using a semiclassical approach, we have considered electron-, proton-, and ionized helium-impact line widths and shifts for
the F III 2p3
4So-3s 4P resonant line. Moreover, for 10 F III multiplets where the full semiclassical perturbation approach is not applicable in
an adequate way due to the lack of reliable atomic data, electron-impact line widths have been calculated within the modified
semiempirical approach. Results are obtained as a function of temperature for perturber density of 1017 cm−3. The theoretical data obtained have been used to consider the influence of Stark broadening for A-type star atmosphere conditions.
__________
Published in Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 412–415, May–June, 2005. 相似文献