1,266 research outputs found
Self-Similar Solutions for ADAF with Toroidal Magnetic Fields
We examined the effect of toroidal magnetic fields on a viscous gaseous disk
around a central object under an advection dominated stage. We found
self-similar solutions for radial infall velocity, rotation velocity, sound
speed, with additional parameter [], where
is the Alfv\'en speed and is the isothermal sound
speed. Compared with the non-magnetic case, in general the disk becomes thick
due to the magnetic pressure, and the radial infall velocity and rotation
velocity become fast. In a particular case, where the magnetic field is
dominant, on the other hand, the disk becomes to be magnetically supported, and
the nature of the disk is significantly different from that of the weakly
magnetized case.Comment: 5pages, 2figures, PASJ 58 (2006) in pres
Relativistic Radiative Flow in a Luminous Disk II
Radiatively-driven transfer flow perpendicular to a luminous disk is examined
in the relativistic regime of , taking into account the gravity of the
central object. The flow is assumed to be vertical, and the gas pressure as
well as the magnetic field are ignored. Using a velocity-dependent variable
Eddington factor, we can solve the rigorous equations of the relativistic
radiative flow accelerated up to the {\it relativistic} speed. For sufficiently
luminous cases, the flow resembles the case without gravity. For less-luminous
or small initial radius cases, however, the flow velocity decreases due to
gravity. Application to a supercritical accretion disk with mass loss is
briefly discussed.Comment: 7 pages, 5 figure
Radiative Transfer and Limb Darkening of Accretion Disks
Transfer equation in a geometrically thin accretion disk is reexamined under
the plane-parallel approximation with finite optical depth. Emergent intensity
is analytically obtained in the cases with or without internal heating. For
large or infinite optical depth, the emergent intensity exhibits a usual
limb-darkening effect, where the intensity linearly changes as a function of
the direction cosine. For small optical depth, on the other hand, the
angle-dependence of the emergent intensity drastically changes. In the case
without heating but with uniform incident radiation at the disk equator, the
emergent intensity becomes isotropic for small optical depth. In the case with
uniform internal heating, the limb brightening takes place for small optical
depth. We also emphasize and discuss the limb-darkening effect in an accretion
disk for several cases.Comment: 7 pages, 4 figure
Relativistic Radiation Hydrodynamical Accretion Disk Winds
Accretion disk winds browing off perpendicular to a luminous disk are
examined in the framework of fully special relativistic radiation
hydrodynamics. The wind is assumed to be steady, vertical, and isothermal. %and
the gravitational fields is approximated by a pseudo-Newtonian potential. Using
a velocity-dependent variable Eddington factor, we can solve the rigorous
equations of relativistic radiative hydrodynamics, and can obtain radiatively
driven winds accelerated up to the {\it relativistic} speed. For less luminous
cases, disk winds are transonic types passing through saddle type critical
points, and the final speed of winds increases as the disk flux and/or the
isothermal sound speed increase. For luminous cases, on the other hand, disk
winds are always supersonic, since critical points disappear due to the
characteristic nature of the disk gravitational fields. The boundary between
the transonic and supersonic types is located at around , where is the
radiative flux at the critical point normalized by the local Eddington
luminosity, is the enthalpy of the gas divided by the
rest mass energy, and is the Lorentz factor of the wind
velocity at the critical point. In the transonic winds, the final speed becomes
0.4--0.8 for typical parameters, while it can reach in the
supersonic winds.Comment: 6 pages, 5 figures; PASJ 59 (2007) in pres
Generic formal fibers and analytically ramified stable rings
Let be a local Noetherian domain of Krull dimension . Heinzer,
Rotthaus and Sally have shown that if the generic formal fiber of has
dimension , then is birationally dominated by a one-dimensional
analytically ramified local Noetherian ring having residue field finite over
the residue field of . We explore further this correspondence between prime
ideals in the generic formal fiber and one-dimensional analytically ramified
local rings. Our main focus is on the case where the analytically ramified
local rings are stable, and we show that in this case the embedding dimension
of the stable ring reflects the embedding dimension of a prime ideal maximal in
the generic formal fiber, thus providing a measure of how far the generic
formal fiber deviates from regularity. A number of characterizations of
analytically ramified local stable domains are also given.Comment: To appear in Nagoya J. Mat
Self-similar structure of a hot magnetized flow with thermal conduction
We have explored the structure of hot magnetized accretion flow with thermal
conduction. The importance of thermal conduction in hot accretion flows has
been confirmed by observations of the hot gas surrounding Sgr and a few
other nearby galactic nuclei. For a steady state structure of such accretion
flows a set of self similar solutions are presented. In this paper, we have
actually tried to re-check the solution presented by Abbassi et al. (2008)
using a physical constrain. In this study we find that Eq 29 places a new
constrain that limits answers presented by Abbassi et al. 2008. In that paper
the parameter space in which it is established in the new constrain was
plotted. However, the new requirement makes up only a small parameter space
with physically acceptable solutions. And now in this manuscript we have
followed the idea with more effort, and tried to find out how thermal
conduction influences the structur of the disks in a physical parameter space.
We have found out that the existence of thermal conduction will lead to
reduction of accretion and radial and azimuthal velocities as well as the
vertical thickness of the disk, which is slightly reduced. Moreover, the
surface density of the disk will increase when the thermal conduction becomes
important in the hot magnetized flow.Comment: Accepted for publication, AP
形状的整合性および配置実現性に基づく3次元物体認識に関する研究
Chukyo University(中京大学
Cloning and sequence analysis of complementary DNA encoding a precursor for chicken natriuretic peptide
AbstractChicken α-natriuretic peptide (α-chNP) has been identified in chicken heart, which showed higher homology to brain natriuretic peptide (BNP) than to atrial natriuretic peptide (ANP) [1]. Complementary DNA (cDNA) clone encoding a chNP precursor (pre-chNP) precursor (pre-chNP) was isolated from cardiac cDNA library and sequenced. Pre-chNP was 140-residue signal peptide at the N-terminus and α-chNP at the C-terminus, and did not exhibit high homology to poreine BNP except for the C-terminal region. However, a characteristic AT-rich nucleotide sequence commonly found in mammalian BNPs was also present in the 3′-untranslated region. Thus, chNP is concluded to be classified into the BNP-typ
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