Search results for "Stability."
showing 10 items of 3015 documents
Etude de la stabilité de films industriels de PLA et de leur modification de surface pour des applications en tant qu'emballage alimentaire biodégrad…
2017
Poly(lactic acid) (PLA) is a biodegradable and renewable polyester, which is considered as the most promising eco-friendly substitute of conventional plastics. It is mainly used for food packaging applications, but some drawbacks still reduce its applications. On the one hand, its low barrier performance to gases (e.g. O2 and CO2) limits its use for applications requiring low gas transfer, such as modified atmosphere packaging (MAP) or for carbonate beverage packaging. On the other hand, its natural water sensitivity, which contributes to its biodegradation, limits its use for high moisture foods with long shelf life.Other biopolymers such as wheat gluten (WG) can be considered as interesti…
Gelled Electrolyte Containing Phosphonium Ionic Liquids for Lithium-Ion Batteries
2018
In this work, new gelled electrolytes were prepared based on a mixture containing phosphonium ionic liquid (IL) composed of trihexyl(tetradecyl)phosphonium cation combined with bis(trifluoromethane)sulfonimide [TFSI] counter anions and lithium salt, confined in a host network made from an epoxy prepolymer and amine hardener. We have demonstrated that the addition of electrolyte plays a key role on the kinetics of polymerization but also on the final properties of epoxy networks, especially thermal, thermo-mechanical, transport, and electrochemical properties. Thus, polymer electrolytes with excellent thermal stability (>
Localization from inertial data and sporadic position measurements
2020
International audience; A novel estimation strategy for inertial navigation in indoor/outdoor environments is proposed with a specific attention to the sporadic nature of the non-periodic measurements. After introducing the inertial navigation model, we introduce an observer providing an asymptotic estimate of the plant state. We use a hybrid dynamical systems representation for our results, in order to provide an effective, and elegant theoretical framework. The estimation error dynamics with the proposed observer shows a peculiar cascaded interconnection of three subsystems (allowing for intuitive gain tuning), with perturbations occurring either on the jump or on the flow dynamics (depen…
Intermittency in the homopolar disk-dynamo
2006
We study a modified Bullard dynamo and show that this system is equivalent to a nonlinear oscillator subject to a multiplicative noise. The stability analysis of this oscillator is performed. Two bifurcations are identified, first towards an \lq\lq intermittent\rq\rq state where the absorbing (non-dynamo) state is no more stable but the most probable value of the amplitude of the oscillator is still zero and secondly towards a \lq\lq turbulent\rq\rq (dynamo) state where it is possible to define unambiguously a (non-zero) most probable value around which the amplitude of the oscillator fluctuates. The bifurcation diagram of this system exhibits three regions which are analytically characteri…
Generation of a 160-GHz transform-limited pedestal-free pulse train through multiwave mixing compression of a dual-frequency beat signal.
2002
International audience; We report the experimental generation of a 160-GHz picosecond pulse train at 1550 nm, using multiple four-wave mixing temporal compression of an initial dual-frequency beat signal in the anomalous-dispersion regime of a nonzero dispersion-shifted fiber. Complete intensity and phase characterizations of the pulse train were carried out by means of a frequency-resolved optical gating technique, showing that 1.27-ps transform-limited pedestal-free Gaussian pulses were generated.
Sub-nanosecond nonlinear pulse shaping in microfiber resonators
2009
Thanks to their small size and large index contrast allowing for tight field confinement, optical microfibers are of great interest in nonlinear optics. Their properties have recently been exploited in various devices for supercontinuum generation, pulse compression [1] and third-harmonic generation [2]. Combining field confinement and field enhancement in a loop or knot resonator can result in low-threshold non-linear microfibre devices, in which pulse shaping effects and bistability can be obtained. Such a behaviour has already been observed at a power level of ten milliwatts with millisecond time response, in the case of thermally-induced non-linearity in silica microfibres [3]. In contr…
Slow and fast nonlinearities in microfiber resonators
2008
Nonlinear optical properties of microfiber resonators are investigated. First, a miniature optical resonator standing in air is realized out of a silica microfiber, and measurements of the intensity transfer function show a wide variety of hysteresis cycles obtained at low scanning frequency of the input power. The results are satisfactorily interpreted through the action of thermally-induced nonlinear phase shifts. Secondly, we discuss the conditions under which the fast Kerr nonlinearity can be used efficiently in microfiber resonators under pulsed optical operation.
Soliton generation and rogue-wave like behavior through fourth order modulation instability
2010
International audience; We numerically study the dynamics of ultra-broadband wavelength converters based on fourth-order scalar modulation instability. We report the spontaneous emergence of solitons and trapped radiation waves as well as L-shaped associated statistical signatures.
Near-field control of optical bistability in a nanocavity
2009
Micro- and nanocavities allow for strong light confinement in very small volume [1]. They give opportunities for new experiments such as cavity quantum electrodynamics, waveguiding, light slowing or trapping…[2] The increase of the electromagnetic (EM) field in the cavity enhances the interaction between light and matter, resulting in the possible observation of nonlinear effects [3]. Several studies have recently been published on the observation and characterisation of nonlinear silicon cavities [4]. As a step further, we propose and demonstrate the feasibility of an innovative way to mechanically control the bistable operating regime of a nanovavity. Using a near-field tip, we switch the…
Bistable Device based on the Kerr Effect in a Microfiber Resonator
2007
We propose a bistable device based on the Kerr effect in a microfiber resonator. Our simulations show that low switching powers (in the order of a few tens of mW) are expected with tellurite microfibers.