234 research outputs found
A Novel Dynamic Event-triggered Mechanism for Dynamic Average Consensus
This paper studies a challenging issue introduced in a recent survey, namely
designing a distributed event-based scheme to solve the dynamic average
consensus (DAC) problem. First, a robust adaptive distributed event-based DAC
algorithm is designed without imposing specific initialization criteria to
perform estimation task under intermittent communication. Second, a novel
adaptive distributed dynamic event-triggered mechanism is proposed to determine
the triggering time when neighboring agents broadcast information to each
other. Compared to the existing event-triggered mechanisms, the novelty of the
proposed dynamic event-triggered mechanism lies in that it guarantees the
existence of a positive and uniform minimum inter-event interval without
sacrificing any accuracy of the estimation, which is much more practical than
only ensuring the exclusion of the Zeno behavior or the boundedness of the
estimation error. Third, a composite adaptive law is developed to update the
adaptive gain employed in the distributed event-based DAC algorithm and dynamic
event-triggered mechanism. Using the composite adaptive update law, the
distributed event-based solution proposed in our work is implemented without
requiring any global information. Finally, numerical simulations are provided
to illustrate the effectiveness of the theoretical results.Comment: 9 pages, 8 figure
Application of Fast Deviation Correction Algorithm Based on Shape Matching Algorithm in Component Placement
For contradiction PC template matching between accuracy and speed, combined with the advantages of FPGA high speed parallel computing. This paper presents a FPGA-based rapid correction shape matching algorithm. Mainly in the FPGA, using shape matching and least squares method to calculate the angular deviation chip components. Use single instruction stream algorithm acceleration. Experimental results show that compared with traditional PC template matching algorithms, this algorithm to further improve the correction accuracy and greatly reducing correction time. And SMT machine vision correction can be obtained in a stable and efficient use
Phases of Chiral Gauge Theories
We discuss the behavior of two non-supersymmetric chiral SU(N) gauge
theories, involving fermions in the symmetric and antisymmetric two-index
tensor representations respectively. In addition to global anomaly matching, we
employ a recently proposed inequality constraint on the number of effective low
energy (massless) degrees of freedom of a theory, based on the thermodynamic
free energy. Several possible zero temperature phases are consistent with the
constraints. A simple picture for the phase structure emerges if these theories
choose the phase, consistent with global anomaly matching, that minimizes the
massless degree of freedom count defined through the free energy. This idea
suggests that confinement with the preservation of the global symmetries
through the formation of massless composite fermions is in general not
preferred. While our discussion is restricted mainly to bilinear condensate
formation, higher dimensional condensates are considered for one case. We
conclude by commenting briefly on two related supersymmetric chiral theories.Comment: 23 pages, 2 figures, ReVTeX, improved forma
Electroweak Physics for Color Superconductivity
We construct the effective theories describing the electroweak interactions
for the low energy excitations associated with the color superconductive phases
of QCD at high matter density. The main result, for the 3 flavor case, is that
the quasiparticle Goldstone boson decay into two physical massless
photons is identical to the zero density case once we use the new Goldstone
decay constant and the modified electric charge ,
with and the strong coupling constant. For 2
flavors we find that the coupling of the quarks to the neutral vector boson
is modified with respect to the zero density case. We finally point out
possible applications of our result to the physics of compact objects.Comment: 23 pages, 1 Figure, RevTex. More discussion and references adde
Low Energy Theory for 2 flavors at High Density QCD
We construct the effective Lagrangian describing the low energy excitations
for Quantum Chromodynamics with two flavors at high density. The non-linear
realization framework is employed to properly construct the low energy
effective theory. The light degrees of freedom, as required by 't Hooft anomaly
conditions, contain massless fermions which we properly include in the
effective Lagrangian. We also provide a discussion of the linearly realized
Lagrangian.Comment: 17 pages, RevTeX format, references added. To appear in Phys. Rev.
Synthesis of ultrahigh-metal-density single-atom catalysts via metal sulfide-mediated atomic trapping
Single-atom catalysts (SACs) exhibit exceptional intrinsic activity per metal site, but are often limited by low metal loading, which compromises the overall catalytic performance. Pyrolytic strategies commonly used for synthesizing SACs generally suffer from aggregation at high metal loadings. Here we report a universal synthesis approach for ultrahigh-density metal–nitrogen–carbon (UHDM–N–C) SACs via a metal-sulfide-mediated atomization process. We show that our approach is general for transition, rare-earth and noble metals, achieving 17 SACs with metal loadings >20 wt% (including a loading of 26.9 wt% for Cu, 31.2 wt% for Dy and 33.4 wt% for Pt) at 800 °C, as well as high-entropy quinary and vicenary SACs with ultrahigh metal contents. In situ X-ray diffraction and transmission electron microscopy alongside molecular simulations reveals a dynamic nanoparticle-to-single atom transformation process, including thermally driven decomposition of the metal sulfide and the trapping of liberated metal atoms to form thermodynamically stable M–N–C moieties. Our studies indicate that a high N-doping is crucial for achieving ultrahigh-loading metal atoms and a metal-sulfide-mediated process is essential for avoiding metal aggregation at high loadings. As a demonstration, the metal-loading-dependent activity in electrocatalytic oxygen evolution reaction is demonstrated on SACs with increasing Ni content. (Figure presented.
Enhanced Global Symmetry Constraints on epsilon Terms
Recently it has been proposed that the physical spectrum of a vector-like
gauge field theory may exhibit an enhanced global symmetry near a
chiral/conformal phase transition. The new symmetry is related to the
possibility, supported by various investigations, that a parity-doubled
spectrum develops as the number of fermions Nf is increased to a critical value
above which it is expected that the symmetric phase is restored.
We show that parity-doubling together with the associated enhanced global
symmetry severely constrains the epsilon terms of the effective Lagrangian
involving Goldstone bosons as well as massive spin-1 particles. We extend our
analysis to underlying fermions in pseudo-real representations of the gauge
group.Comment: 22 pages, RevTeX format. Appendix A added. Accepted in Nucl. Phys.
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