611 research outputs found
A Novel Hash Scheme Based on SNP-PLCM
AbstractBy combining the traditional iteration structure of Hash function with the dynamic S-boxes, a novel keyed Hash function is presented. The proposed approach can give a chaotic Hash value by means of the lookup table of functions and chaotic dynamic S-box. Compared with the existing chaotic Hash functions, this method improves computational performance of Hash system by using the chaotic S-box substitution. Theoretical and experimental results show that the proposed method has not only strong one way property, sensitivity to initial conditions and chaotic system's parameters, but also high speed
Social contagions on interdependent lattice networks
Although an increasing amount of research is being done on the dynamical processes on interdependent spatial networks, knowledge of how interdependent spatial networks influence the dynamics of social contagion in them is sparse. Here we present a novel non-Markovian social contagion model on interdependent spatial networks composed of two identical two-dimensional lattices. We compare the dynamics of social contagion on networks with different fractions of dependency links and find that the density of final recovered nodes increases as the number of dependency links is increased. We use a finite-size analysis method to identify the type of phase transition in the giant connected components (GCC) of the final adopted nodes and find that as we increase the fraction of dependency links, the phase transition switches from second-order to first-order. In strong interdependent spatial networks with abundant dependency links, increasing the fraction of initial adopted nodes can induce the switch from a first-order to second-order phase transition associated with social contagion dynamics. In networks with a small number of dependency links, the phase transition remains second-order. In addition, both the second-order and first-order phase transition points can be decreased by increasing the fraction of dependency links or the number of initially-adopted nodes.This work was partially supported by National Natural Science Foundation of China (Grant Nos 61501358, 61673085), and the Fundamental Research Funds for the Central Universities. (61501358 - National Natural Science Foundation of China; 61673085 - National Natural Science Foundation of China; Fundamental Research Funds for the Central Universities)Published versio
Integrating non-planar metamaterials with magnetic absorbing materials to yield ultra-broadband microwave hybrid absorbers
Broadening the bandwidth of electromagnetic wave absorbers has greatly challenged material scientists. Here, we propose a two-layer hybrid absorber consisting of a non-planar metamaterial (MM) and a magnetic microwave absorbing material (MAM). The non-planar MM using magnetic MAMs instead of dielectric substrates shows good low frequency absorption and low reflection across a broad spectrum. Benefiting from this and the high frequency strong absorption of the MAM layer, the lightweight hybrid absorber exhibits 90% absorptivity over the whole 2-18 GHz range. Our result reveals a promising and flexible method to greatly extend or control the absorption bandwidth of absorbers. (C) 2014 AIP Publishing LLC
Two spatially separated phases in semiconducting RbFeS
We report neutron scattering and transport measurements on semiconducting
RbFeS, a compound isostructural and isoelectronic to the
well-studied FeSe K, Rb, Cs, Tl/K) superconducting
systems. Both resistivity and DC susceptibility measurements reveal a magnetic
phase transition at K. Neutron diffraction studies show that the 275 K
transition originates from a phase with rhombic iron vacancy order which
exhibits an in-plane stripe antiferromagnetic ordering below 275 K. In
addition, interdigitated mesoscopically with the rhombic phase is an ubiquitous
phase with iron vacancy order. This phase has a
magnetic transition at K and an iron vacancy order-disorder
transition at K. These two different structural phases are closely
similar to those observed in the isomorphous Se materials. Based on the close
similarities of the in-plane antiferromagnetic structures, moments sizes, and
ordering temperatures in semiconducting RbFeS and
KFeSe, we argue that the in-plane antiferromagnetic order
arises from strong coupling between local moments. Superconductivity,
previously observed in the FeSeS system, is absent
in RbFeS, which has a semiconducting ground state. The
implied relationship between stripe/block antiferromagnetism and
superconductivity in these materials as well as a strategy for further
investigation is discussed in this paper.Comment: 7 pages, 5 figure
- …