441 research outputs found
Constructing multiwing attractors from a robust chaotic system with non-hyperbolic equilibrium points
We investigate a three-dimensional (3D) robust chaotic system which only holds two nonhyperbolic equilibrium points, and finds the complex dynamical behaviour of position modulation beyond amplitude modulation. To extend the application of this chaotic system, we initiate
a novel methodology to construct multiwing chaotic attractors by modifying the position and amplitude parameters. Moreover, the signal amplitude, range and distance of the generated multiwings can be easily adjusted by using the control parameters, which enable us to enhance the potential application in chaotic cryptography and secure communication. The effectiveness of the theoretical analyses is confirmed by numerical simulations. Particularly, the multiwing
attractor is physically realized by using DSP (digital signal processor) chip
A novel chaotic system and its topological horseshoe
Based on the construction pattern of Chen, Liu and Qi chaotic systems, a new threedimensional (3D) chaotic system is proposed by developing Lorenz chaotic system. It’s found that when parameter e varies, the Lyapunov exponent spectrum keeps invariable, and the signal amplitude can be controlled by adjusting e. Moreover, the horseshoe chaos in this system is investigated based on the topological horseshoe theory
High-responsivity vertical-illumination Si/Ge uni-traveling-carrier photodiodes based on silicon-on-insulator substrate
Si/Ge uni-traveling carrier photodiodes exhibit higher output current when
space-charge effects are overcome and thermal effects are suppressed, which is
highly beneficial for increasing the dynamic range of various microwave
photonic systems and simplifying high-bit-rate digital receivers in different
applications. From the point of view of packaging, detectors with
vertical-illumination configuration can be easily handled by pick-and-place
tools and are a popular choice for making photo-receiver modules. However,
vertical-illumination Si/Ge uni-traveling carrier (UTC) devices suffer from
inter-constraint between high speed and high responsivity. Here, we report a
high responsivity vertical-illumination Si/Ge UTC photodiode based on a
silicon-on-insulator substrate. The maximum absorption efficiency of the
devices was 2.4 times greater than the silicon substrate owing to constructive
interference. The Si/Ge UTC photodiode was successfully fabricated and had a
dominant responsivity at 1550 nm of 0.18 A/W, a 50% improvement even with a 25%
thinner Ge absorption layer.Comment: 5pages,2figure
Quenching for a Non-Newtonian Filtration Equation with a Singular Boundary Condition
This paper deals with a nonlinear p-Laplacian equation with singular boundary conditions. Under proper conditions, the solution of this equation quenches in finite time and the only quenching point thatis x=1
are obtained. Moreover, the quenching rate of this equation is established. Finally, we give an example of an application of our results
The effect of continuous venovenous hemofiltration on neutrophil gelatinase-associated lipocalin plasma levels in patients with septic acute kidney injury
International audienceCe texte d’introduction au dossier de Flux 2017/2 (N° 108) questionne l’émergence de la thématique de la circularité des matières dans les politiques publiques urbaines contemporaines. Les articles ont en commun de porter une attention minutieuse à la matérialité des flux qui traversent et constituent la ville et aux objets sociaux qui la composent. Ils analysent les modalités et les conséquences de leur mise en circulation, ainsi que les régulations et les conflits qui l’accompagnent. Que l’ensemble des articles traite de pratiques et de politiques ancrées dans l’espace de la région de Lyon résulte moins d’une volonté monographique que d’une rencontre en partie fortuite. Mais cela souligne en tout cas l’importance d’une approche toujours attentive aux faits géographiques et aux effets de lieu dans la diversité de leurs échelles. Trois thématiques transversales sont présentes : d’abord, en identifiant de nouvelles ressources, les articles permettent de réfléchir à l’invention et à la construction de nouveaux circuits pour les matières. Ensuite, la régulation de ces circuits implique l’identification de nouveaux acteurs et la mise en place de nouvelles formes de relations avec les producteurs et gestionnaires des matières, formant donc l’espace d’une gouvernance renouvelée. Enfin, si ces circuits se structurent dans un espace qui est celui de la proximité géographique, ils s’inscrivent néanmoins dans une logique relationnelle qui ne cesse de questionner les normes et les échelles. Ce numéro permet ainsi de nuancer et de re-matérialiser les injonctions à faire advenir l’économie circulaire dans les villes
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