نتایج جستجو برای: hole density

تعداد نتایج: 465567  

2006
James Etherington Witold Maciejewski

If supermassive black holes in centres of galaxies form by merging of black-hole remnants of massive Population III stars, then there should be a few black holes of mass one or two orders of magnitude smaller than that of the central ones, orbiting around the centre of a typical galaxy. These black holes constitute a weak perturbation in the gravitational potential, which can generate wave phen...

2016
Jian Wang Fujun Zhang Lingliang Li Qiaoshi An Jian Zhang Weihua Tang Feng Teng

Polymer solar cells (PSCs) with different anode buffer layers were fabricated to investigate dipoleassisted hole extraction on the performance improvement of PSCs. The power conversion efficiency (PCE) of PSCs was increased from 4.77% to 6.18% with 29.6% improvement due to the increased short circuit current density (Jsc) from 12.00 to 15.65 mA/cm 2 induced by the oriented LiF dipole-assisted h...

2008
A. Bartetzko A. T. Fisher

[1] We compile and compare petrophysical data from the upper oceanic crust in Hole U1301B, on 3.5 Ma seafloor on the eastern flank of the Juan de Fuca Ridge. Measurements include core-scale (lab-based) and in situ (wireline) measurements of formation porosity, electrical resistivity, bulk density, P wave velocity, and gamma ray emission. A comparison between Hole U1301B data and those from othe...

Journal: :Science 2014
Lauren E Hayward David G Hawthorn Roger G Melko Subir Sachdev

The hole-doped cuprate high-temperature superconductors enter the pseudogap regime as their superconducting critical temperature, Tc, falls with decreasing hole density. Recent x-ray scattering experiments in YBa2Cu3O(6+x) observe incommensurate charge-density wave fluctuations whose strength rises gradually over a wide temperature range above Tc, but then decreases as the temperature is lowere...

Journal: :Physical review. B, Condensed matter 1994
Müller-Hartmann Ventura

We analyze the motion of a single hole on a Néel background, neglecting spin fluctuations. Brinkman and Rice studied this problem on a cubic lattice, introducing the retraceable-path approximation for the hole Green's function, exact in a one-dimensional lattice. Metzner et al. showed that the approximation also becomes exact in the infinite-dimensional limit. We introduce a new approach to thi...

2008
Christopher S. Reynolds Andrew C. Fabian

We address the ability of broad iron emission lines from black hole accretion disks to diagnose the spin of the black hole. Using a high-resolution 3-dimensional MHD simulation of a geometrically-thin accretion disk in a Pseudo-Newtonian potential, we show that both the midplane density and the vertical column density of the accretion flow drop dramatically over a narrow range of radii close to...

2008
Ross J. McLure James S. Dunlop

Virial black-hole mass estimates are presented for 12698 quasars in the redshift interval 0.1 ≤ z ≤ 2.1, based on modelling of spectra from the Sloan Digital Sky Survey (SDSS) first data release . The black-hole masses of the SDSS quasars are found to lie between ≃ 10 M⊙ and an upper limit of ≃ 3 × 10 9 M⊙, entirely consistent with the largest black-hole masses found to date in the local Univer...

In this paper the dynamic of a droplet on a surface with a hole is investigated under gravitational effect by using lattice Boltzmann method. Incompressible two-phase flow with high density ratio proposed by Lee is considered. Cahn’s theory is used to observe the wettability of the surface in contact with liquid and gas phases. Several parameters such as contact angle, surface tension and gravi...

2008
Rebecca G. Martin Christopher A. Tout

We consider the shape of an accretion disc whose outer regions are misaligned with the spin axis of a central black hole and calculate the steady state form of the warped disc in the case where the viscosity and surface densities are power laws in the distance from the central black hole. We discuss the shape of the resulting disc in both the frame of the black hole and that of the outer disc. ...

Journal: :international journal of civil engineering 0
m. salamatian hafez st, amirkabir university of technology a. r. zarrati hafez st, amirkabir university of technology s. a. zokaei hafez st, amirkabir university of technology m. karimaee hafez st, amirkabir university of technology

the efficiency of a collar in reducing the scour depth around circular and rectangular piers is studied at different flow intensities (ratio of upstream shear stress to sediment critical shear stress). rectangular piers aligned with the flow as well as skewed at 5º, 10º, 20º were examined. previous studies had shown that with collar the equilibrium time of scouring increases considerably. to re...

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