نتایج جستجو برای: mass density
تعداد نتایج: 849091 فیلتر نتایج به سال:
Astrophysical observations indicate that the \Local Universe" has a relatively lower matter density ( 0) than the predictions of the standard in ation cosmology and the large-scale motions of galaxies which provide a mean mass density to be very close to unity. In such a local underdense region the Hubble expansion may not be representative of the global behaviour. Utilizing an underdense spher...
We discuss the correlation function of hadronic currents in the Schwinger model at finite temperature T. We explicitly construct the retarded correlator in real time and obtain analytical results for the Euclidean correlator on a torus. Both constructions lead to the same finite temperature spectral function. The spatial screening lengths in the mesonic channels are related to the dynamical mes...
The effective mass density of an inhomogeneous medium is discussed. Random configurations of circular cylindrical scatterers are considered, in various physical contexts: fluid cylinders in another fluid, elastic cylinders in a fluid or in another solid, and movable rigid cylinders in a fluid. In each case, time-harmonic waves are scattered, and an expression for the effective wavenumber due to...
An experimental study of the heat capacity, mass density, magnetic-field-induced optical birefringence, linewidth and intensity of scattered light, and the viscosities associated with nematic order parameter fluctuations and fluid flow has been performed on an achiral bent-core liquid crystal above its clearing point temperature. The measurements reveal a transition between two optically isotro...
We study eigenvibrations for inhomogeneous string consisting of two parts with strongly contrasting stiffness and mass density. In this work we treat a critical case for the high frequency approximations, namely the case when the order of mass density inhomogeneity is the same as the order of stiffness inhomogeneity, with heavier part being softer. The limit problem for high frequency approxima...
The relative brightnesses of standard candles have long been known to be potentially powerful probes of distance. The distance modulus, the difference between observed and absolute magnitudes, has been associated with the values of the cosmological parameters: Hubble’s constant H0, the mass density ΩM and the cosmological constant ΩΛ. In the literature the relationship between these parameters ...
BACKGROUND The aim of this study was to investigate the influence of body mass index, body weight, lean mass, fat mass, and basal energy expenditure on bone mineral density in postmenopausal women. METHODS This was a cross-sectional, descriptive study of a sample of 50 women, with minimum time since menopause between 1 and 10 years. Bone mineral density was assessed at the lumbar spine (L2-L4...
We consider time-harmonic wave scattering from an inhomogeneous isotropic medium supported in a bounded domain ⊂ RN (N ≥ 2). In a subregion D , the medium is supposed to be lossy and have a large mass density. We study the asymptotic development of the wave field as the mass density ρ → +∞ and show that the wave field inside D will decay exponentially while the wave filed outside the medium wil...
We point out that there is no cosmological gravitino problem in a certain class of gauge-mediated supersymmetry-breaking (GMSB) models. The constant term in the superpotential naturally causes small mixings between the standard-model and messenger fields, which give rise to late-time decays of the lightest messenger fields. This decay provides an exquisite amount of entropy, which dilutes the t...
We propose a type of elastic metamaterial comprising fluid-solid composite inclusions which can possess a negative shear modulus and negative mass density over a large frequency region. Such a material has the unique property that only transverse waves can propagate with a negative dispersion while longitudinal waves are forbidden. This leads to many interesting phenomena such as negative refra...
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