15,792 research outputs found
The colour of the narrow line Sy1-blazar 0324+3410
Aims. We investigate the properties of the host galaxy of the blazar
J0324+3410 (B2 0321+33) by the analysis of B and R images obtained with the NOT
under good photometric conditions. Methods: The galaxy was studied using
different methods: Sersic model fitting, unsharp-masked images, B-R image and
B-R profile analysis. Results: The images show that the host galaxy has a
ring-like morphology. The B-R colour image reveals two bluish zones: one that
coincides with the nuclear region, interpreted as the signature of emission
related to the active nucleus, the other zone is extended and is located in the
host ring-structure. We discuss the hypothesis that the later is thermal
emission from a burst of star formation triggered by an interacting/merging
process
Young's experiment and the finiteness of information
Young's experiment is the quintessential quantum experiment. It is argued
here that quantum interference is a consequence of the finiteness of
information. The observer has the choice whether that information manifests
itself as path information or in the interference pattern or in both partially
to the extent defined by the finiteness of information.Comment: 5 pages, 3 figures, typos remove
Generation of slow intense optical solitons in a resonance photonic crystal
We demonstrate interesting and previously unforeseen properties of a pair of
gap solitons in a resonant photonic crystal which are predicted and explained
in a physically transparent form using both analytical and numerical methods.
The most important result is the fact that an oscillating gap soliton created
by the presence of a localized population inversion inside the crystal can be
manipulated by means of a proper choice of bit rate, phase and amplitude
modulation. Developing this idea, we are able to obtain qualitatively different
regimes of a resonant photonic crystal operation. In particular, a noteworthy
observation is that both the delay time and amplitude difference must exceed a
certain level to ensure effective control over the soliton dynamics
Spatial fluctuations of a surviving particle in the trapping reaction
We consider the trapping reaction, , where and particles
have a diffusive dynamics characterized by diffusion constants and .
The interaction with particles can be formally incorporated in an effective
dynamics for one particle as was recently shown by Bray {\it et al}. [Phys.
Rev. E {\bf 67}, 060102 (2003)]. We use this method to compute, in space
dimension , the asymptotic behaviour of the spatial fluctuation,
, for a surviving particle in the perturbative regime,
, for the case of an initially uniform distribution of
particles. We show that, for , with
. By contrast, the fluctuations of paths constrained to return to
their starting point at time grow with the larger exponent 1/3. Numerical
tests are consistent with these predictions.Comment: 10 pages, 5 figure
Perbandingan Ppc Dan Faktor-faktor Yang Mempengaruhi Pada Dua Proyek Apartemen
Dalam perkembangan dunia konstruksi yang semakin komplek, sering terjadi pekerjaan yang tidak dapat diselesaikan sesuai dengan jadwal perencanaan yang ada pada action plan. Penelitian ini bertujuan untuk menilai suatu perencanaan proyek dengan menghitung Percent Plan Completed dan juga mendapatkan faktor-faktor penyebab tidak tercapainya rencana pekerjaan (Reason Not Complete). Hal ini dilakukan dengan menerapkan kontrol aliran kerja yang berkesinambungan agar perencanaan menjadi lebih handal. Selain itu juga akan diteliti mengenai penggunaan kontrol aliran kerja sistem last planner pada suatu proyek konstruksi. Penelitian ini telah dilakukan selama 19 minggu. Hasil penelitian menunjukkan bahwa rata-rata PPC (Percent Plan Completed) sebesar 61,15% dan 57,32%, kemudian faktor penyebab dominan tidak terselesaikannya pekerjaan dalam proyek ini adalah faktor predecessor. Selain itu proyek yang diamati ini sedikit melakukan kontrol aliran kerja sistem last planner. Dimana aliran kerja yang dilakukan yaitu action plan2 mingguan dan daily meeting yang dilakukan seminggu sekali
Interface enhancement of Gilbert damping from first-principles
The enhancement of Gilbert damping observed for Ni80Fe20 (Py) films in
contact with the non-magnetic metals Cu, Pd, Ta and Pt, is quantitatively
reproduced using first-principles scattering theory. The "spin-pumping" theory
that qualitatively explains its dependence on the Py thickness is generalized
to include a number of factors known to be important for spin transport through
interfaces. Determining the parameters in this theory from first-principles
shows that interface spin-flipping makes an essential contribution to the
damping enhancement. Without it, a much shorter spin-flip diffusion length for
Pt would be needed than the value we calculate independently
Ni(111)|Graphene|h-BN Junctions as Ideal Spin Injectors
Deposition of graphene on top of hexagonal boron nitride (h-BN) was very
recently demonstrated while graphene is now routinely grown on Ni. Because the
in-plane lattice constants of graphite, h-BN, graphite-like BC2N and of the
close-packed surfaces of Co, Ni and Cu match almost perfectly, it should be
possible to prepare ideal interfaces between these materials which are
respectively, a semimetal, insulator, semiconductor, ferromagnetic and
nonmagnetic metals. Using parameter-free energy minimization and electronic
transport calculations, we show how h-BN can be combined with the perfect spin
filtering property of Ni|graphite and Co|graphite interfaces to make perfect
tunnel junctions or ideal spin injectors (SI) with any desired resistance-area
product.Comment: 4 pages, 4 figures. Accepted for publication in Physical Review
The structure of one-relator relative presentations and their centres
Suppose that G is a nontrivial torsion-free group and w is a word in the
alphabet G\cup\{x_1^{\pm1},...,x_n^{\pm1}\} such that the word w' obtained from
w by erasing all letters belonging to G is not a proper power in the free group
F(x_1,...,x_n). We show how to reduce the study of the relative presentation
\^G= to the case n=1. It turns out that an
"n-variable" group \^G can be constructed from similar "one-variable" groups
using an explicit construction similar to wreath product. As an illustration,
we prove that, for n>1, the centre of \^G is always trivial. For n=1, the
centre of \^G is also almost always trivial; there are several exceptions, and
all of them are known.Comment: 15 pages. A Russian version of this paper is at
http://mech.math.msu.su/department/algebra/staff/klyachko/papers.htm . V4:
the intoduction is rewritten; Section 1 is extended; a short introduction to
Secton 5 is added; some misprints are corrected and some cosmetic
improvements are mad
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