4,325 research outputs found
Design, Fabrication and Characterization of a Piezoelectric Microgenerator Including a Power Management Circuit
We report in this paper the design, fabrication and experimental
characterization of a piezoelectric MEMS microgenerator. This device scavenges
the energy of ambient mechanical vibrations characterized by frequencies in the
range of 1 kHz. This component is made with Aluminum Nitride thin film
deposited with a CMOS compatible process. Moreover we analyze two possible
solutions for the signal rectification: a discrete doubler-rectifier and a full
custom power management circuit. The ASIC developed for this application takes
advantage of diodes with very low threshold voltage and therefore allows the
conversion of extremely low input voltages corresponding to very weak input
accelerations. The volume of the proposed generator is inferior to 1mm3 and the
generated powers are in the range of 1W. This system is intended to supply
power to autonomous wireless sensor nodes.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/EDA-Publishing
Modeling Evolution of Crosstalk in Noisy Signal Transduction Networks
Signal transduction networks can form highly interconnected systems within
cells due to network crosstalk, the sharing of input signals between multiple
downstream responses. To better understand the evolutionary design principles
underlying such networks, we study the evolution of crosstalk and the emergence
of specificity for two parallel signaling pathways that arise via gene
duplication and are subsequently allowed to diverge. We focus on a sequence
based evolutionary algorithm and evolve the network based on two physically
motivated fitness functions related to information transmission. Surprisingly,
we find that the two fitness functions lead to very different evolutionary
outcomes, one with a high degree of crosstalk and the other without.Comment: 18 Pages, 16 Figure
Method of computation of energies in the fractional quantum Hall effect regime
In a previous work, we reported exact results of energies of the ground state
in the fractional quantum Hall effect (FQHE) regime for systems with up to
electrons at the filling factor by using the
method of complex polar coordinates. In this work, we display interesting
computational details of the previous calculation and extend the calculation to
electrons at . Moreover, similar exact results
are derived at the filling for systems with up to electrons. The results that we obtained by analytical calculation are in
good agreement with their analogues ones derived by the method of Monte Carlo
in a precedent work.Comment: 9 pages, 1 figur
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