35,216 research outputs found
The branch processes of vortex filaments and Hopf Invariant Constraint on Scroll Wave
In this paper, by making use of Duan's topological current theory, the
evolution of the vortex filaments in excitable media is discussed in detail.
The vortex filaments are found generating or annihilating at the limit points
and encountering, splitting, or merging at the bifurcation points of a complex
function . It is also shown that the Hopf invariant of knotted
scroll wave filaments is preserved in the branch processes (splitting, merging,
or encountering) during the evolution of these knotted scroll wave filaments.
Furthermore, it also revealed that the "exclusion principle" in some chemical
media is just the special case of the Hopf invariant constraint, and during the
branch processes the "exclusion principle" is also protected by topology.Comment: 9 pages, 5 figure
Electromagnetically controlled multiferroic thermal diode
We propose an electromagnetically tunable thermal diode based on a two phase
multiferroics composite. Analytical and full numerical calculations for
prototypical heterojunction composed of Iron on Barium titanate in the
tetragonal phase demonstrate a strong heat rectification effect that can be
controlled externally by a moderate electric field. This finding is of an
importance for thermally based information processing and sensing and can also
be integrated in (spin)electronic circuits for heat management and recycling.Comment: Accepted in Phys. Rev.
Distributed Adaptive Attitude Synchronization of Multiple Spacecraft
This paper addresses the distributed attitude synchronization problem of
multiple spacecraft with unknown inertia matrices. Two distributed adaptive
controllers are proposed for the cases with and without a virtual leader to
which a time-varying reference attitude is assigned. The first controller
achieves attitude synchronization for a group of spacecraft with a leaderless
communication topology having a directed spanning tree. The second controller
guarantees that all spacecraft track the reference attitude if the virtual
leader has a directed path to all other spacecraft. Simulation examples are
presented to illustrate the effectiveness of the results.Comment: 13 pages, 11 figures. To appear in SCIENCE CHINA Technological
Science
Topological Properties of Spatial Coherence Function
Topology of the spatial coherence function is considered in details. The
phase singularity (coherence vortices) structures of coherence function are
classified by Hopf index and Brouwer degree in topology. The coherence flux
quantization and the linking of the closed coherence vortices are also studied
from the topological properties of the spatial coherence function.Comment: 9 page
Measurement of Cardiac Mechanical Function in Isolated Ventricular Myocytes from Rats and Mice by Computerized Video-Based Imaging
Isolated adult cardiac ventricular myocytes have been a useful model for cardiovascular research for more than 20 years. With the recent advances in cellular physiology and transgenic techniques, direct measurement of isolated ventricular myocyte mechanics is becoming an increasingly important technique in cardiac physiology that provides fundamental information on excitation-contraction coupling of the heart, either in drug intervention or pathological states. The goal of this article is to describe the isolation of ventricular myocytes from both rats and mice, and the use of real-time beat-to-beat simultaneous recording of both myocyte contraction and intracellular Ca(2+) transient
The -log-convexity of Domb's polynomials
In this paper, we prove the -log-convexity of Domb's polynomials, which
was conjectured by Sun in the study of Ramanujan-Sato type series for powers of
. As a result, we obtain the log-convexity of Domb's numbers. Our proof is
based on the -log-convexity of Narayana polynomials of type and a
criterion for determining -log-convexity of self-reciprocal polynomials.Comment: arXiv admin note: substantial text overlap with arXiv:1308.273
Calculations on the Size Effects of Raman Intensities of Silicon Quantum Dots
Raman intensities of Si quantum dots (QDs) with up to 11,489 atoms (about 7.6
nm in diameter) for different scattering configurations are calculated. First,
phonon modes in these QDs, including all vibration frequencies and vibration
amplitudes, are calculated directly from the lattice dynamic matrix by using a
microscopic valence force field model combined with the group theory. Then the
Raman intensities of these quantum dots are calculated by using a
bond-polarizability approximation. The size effects of the Raman intensity in
these QDs are discussed in detail based on these calculations. The calculations
are compared with the available experimental observation. We are expecting that
our calculations can further stimulate more experimental measurements.Comment: 21 pages, 7 figure
On the -log-convexity conjecture of Sun
In his study of Ramanujan-Sato type series for , Sun introduced a
sequence of polynomials as given by
and he conjectured that the polynomials are -log-convex. By
imitating a result of Liu and Wang on generating new -log-convex sequences
of polynomials from old ones, we obtain a sufficient condition for determining
the -log-convexity of self-reciprocal polynomials. Based on this criterion,
we then give an affirmative answer to Sun's conjecture
Inference of mixed information in Formal Concept Analysis
Negative information can be considered twofold: by means
of a negation operator or by capturing the absence of information. In
this second approach, a new framework have to be developed: from the syntax to the semantics, including the management of such generalized knowledge representation. In this work we traverse all these issues in the framework of formal concept analysis, introducing a new set of inference rules to manage mixed (positive and negative) attributes.TIN2014-59471-P of the Science and Innovation
Ministry of Spain, co-funded by the European Regional Development Fund
(ERDF). UNIVERSIDAD DE MÁLAGA. Campus de Excelencia Internacional Andalucía Tech
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