1,318 research outputs found
Accretion of Solid Materials onto Circumplanetary Disks from Protoplanetary Disks
We investigate accretion of solid materials onto circumplanetary disks from
heliocentric orbits rotating in protoplanetary disks, which is a key process
for the formation of regular satellite systems. In the late stage of
gas-capturing phase of giant planet formation, the accreting gas from
protoplanetary disks forms circumplanetary disks. Since the accretion flow
toward the circumplanetary disks affects the particle motion through gas drag
force, we use hydrodynamic simulation data for the gas drag term to calculate
the motion of solid materials. We consider wide range of size for the solid
particles (-m), and find that the accretion efficiency of the
solid particles peaks around 10m-sized particles because energy dissipation of
drag with circum-planetary disk gas in this size regime is most effective. The
efficiency for particles larger than 10m size becomes lower because gas drag
becomes less effective. For particles smaller than 10m, the efficiency is lower
because the particles are strongly coupled with the back-ground gas flow, which
prevent particles from accretion. We also find that the distance from the
planet where the particles are captured by the circumplanetary disks is in a
narrow range and well described as a function of the particle size.Comment: 12 pages, 11 figures, accepted for publication in Ap
The Effect of Poloidal Magnetic Field on Type I Planetary Migration: Significance of Magnetic Resonance
We study the effect of poloidal magnetic field on type I planetary migration
by linear perturbation analysis in the shearing-sheet approximation and the
analytic results are compared with numerical calculations. In contrast to the
unmagnetized case, the basic equations that describe the wake due to the planet
in the disk allow magnetic resonances at which density perturbation diverges.
In order to simplify the problem, we consider the case without
magneto-rotational instability. We perform two sets of analyses:
two-dimensional and three-dimensional. In two-dimensional analysis, we find the
generalization of the torque formula previously known in unmagnetized case. In
three-dimensional calculations, we focus on the disk with very strong magnetic
field and derive a new analytic formula for the torque exerted on the planet.
We find that when Alfven velocity is much larger than sound speed,
two-dimensional torque is suppressed and three-dimensional modes dominate, in
contrast to the unmagnetized case.Comment: 33 pages, 10 figures, typos corrected, discussion added, reference
added, Accepted for publication in Ap
Quantum Kolmogorov Complexity and Quantum Key Distribution
We discuss the Bennett-Brassard 1984 (BB84) quantum key distribution protocol
in the light of quantum algorithmic information. While Shannon's information
theory needs a probability to define a notion of information, algorithmic
information theory does not need it and can assign a notion of information to
an individual object. The program length necessary to describe an object,
Kolmogorov complexity, plays the most fundamental role in the theory. In the
context of algorithmic information theory, we formulate a security criterion
for the quantum key distribution by using the quantum Kolmogorov complexity
that was recently defined by Vit\'anyi. We show that a simple BB84 protocol
indeed distribute a binary sequence between Alice and Bob that looks almost
random for Eve with a probability exponentially close to 1.Comment: typos correcte
Effects of a Supermassive Black Hole Binary on a Nuclear Gas Disk
We study influence of a galactic central supermassive black hole (SMBH)
binary on gas dynamics and star formation activity in a nuclear gas disk by
making three-dimensional Tree+SPH simulations. Due to orbital motions of SMBHs,
there are various resonances between gas motion and the SMBH binary motion. We
have shown that these resonances create some characteristic structures of gas
in the nuclear gas disk, for examples, gas elongated or filament structures,
formation of gaseous spiral arms, and small gas disks around SMBHs. In these
gaseous dense regions, active star formations are induced. As the result, many
star burst regions are formed in the nuclear region.Comment: 19 pages, 11 figures, accepted for publication in Ap
Steady-State Analysis of Load Balancing with Coxian- Distributed Service Times
This paper studies load balancing for many-server ( servers) systems. Each
server has a buffer of size and can have at most one job in service and
jobs in the buffer. The service time of a job follows the Coxian-2
distribution. We focus on steady-state performance of load balancing policies
in the heavy traffic regime such that the normalized load of system is for We identify a set of policies that
achieve asymptotic zero waiting. The set of policies include several classical
policies such as join-the-shortest-queue (JSQ), join-the-idle-queue (JIQ),
idle-one-first (I1F) and power-of--choices (Po) with . The proof of the main result is based on Stein's method and state space
collapse. A key technical contribution of this paper is the iterative state
space collapse approach that leads to a simple generator approximation when
applying Stein's method
Semi-classical correlator for 1/4 BPS Wilson loop and chiral primary operator with large R-charge
We study a holographic description for correlation function of 1/4 BPS Wilson
loop operator and 1/2 BPS local operator carrying a large R-charge of order
\sqrt \lambda. We construct a rotating string solution which is extended in S5
as well as in AdS5. The string solution preserves the 1/8 of the supersymmetry
as expected from the gauge theory computation. By evaluating the string action
including boundary terms we show that the string solution reproduces
correlation function in large J \sim O(\sqrt \lambda) limit. In addition, we
found the second solution for which the "size" of the string becomes larger
than the radius of S5. In the case J=0, this solution reduces to the previously
known unstable string configuration. The gauge theory side also contains a
saddle point which is not on the steepest descent path. We show that the saddle
point value matches for this case as well.Comment: 19 pages, 7 figures, confusing point clarified in subsection 3.5,
reference added, minor correction
Model independent approach to studies of the confining dual Abrikosov vortex in SU(2) lattice gauge theory
We address the problem of determining the type I, type II or borderline dual
superconductor behavior in maximal Abelian gauge SU(2) through the study of the
dual Abrikosov vortex. We find that significant electric currents in the
simulation data call into question the use of the dual Ginzburg Landau Higgs
model in interpreting the data. Further, two definitions of the penetration
depth parameter take two different values. The splitting of this parameter into
two is intricately connected to the existence of electric currents. It is
important in our approach that we employ definitions of flux and electric and
magnetic currents that respect Maxwell equations exactly for lattice averages
independent of lattice spacings. Applied to specific Wilson loop sizes, our
conclusions differ from those that use the dual GLH model.Comment: 18 pages, 14 figures, change title, new anaylysis with more figure
A manual sequence method of peptides and phosphopeptides using 4-(1\u27-cyanoisoindolyl)phenylisothiocyanate.
A method for sequence analysis and identification of phosphoamino acids in peptides based on high performance liquid chromatography (HPLC) is described. The peptides were derivatized with an Edman type reagent, 4-(1\u27-cyanoisoindolyl)phenylisothiocyanate (CIPIC) and subsequently cleaved to generate stable and fluorescent 4-(1\u27-cyanoisoindolyl)phenylthiazolinone (CIP-TZ)-amino acids. Several experimental factors that affected derivatization on membranes were examined. Under the optimized conditions, the CIP-TZ derivatives of Try(p), Thr(p) and Ser(p) were obtained and separated from their parent amino acids with baseline resolution using an isocratic elution system. Up to the 4th residue of phosphorylated pentapeptides was successfully identified, whereas phosphoamino acid residues could not be detected by the conventional procedure using phenylisothiocyanate (PITC). The results demonstrated the potential of CIPIC as a derivatization reagent for peptide sequencing and the applicability of the method for the study and identification of phosphoamino acids in peptides
The effect of maximum normal impact load, absorbed energy and contact impulse on the impact craters volume/depth of DLC coating under repetitive impacts
Recently, the requirements for measuring dynamic responses have become severe and varied in many industrial and research applications such as material testing, model analysis and crash testing1). Surface degradation often occurs due to this dynamic response. This phenomenon also appears in the DLC coatings material. In this present work, a self-developed horizontal impact tester can provides this type of response, which gives an effect to the impact craters volume/depth of DLC coating
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