Search results for " propagation"

Optical bullets and "rockets" in nonlinear dissipative systems and their transformations and interactions

2006

We demonstrate the existence of stable optical light bullets in nonlinear dissipative media for both cases of normal and anomalous chromatic dispersion. The prediction is based on direct numerical simulations of the (3+1)-dimensional complex cubic-quintic GinzburgLandau equation. We do not impose conditions of spherical or cylindrical symmetry. Regions of existence of stable bullets are determined in the parameter space. Beyond the domain of parameters where stable bullets are found, unstable bullets can be transformed into >rockets> i.e. bullets elongated in the temporal domain. A few examples of the interaction between two optical bullets are considered using spatial and temporal interact…

Nonlinear sculpturing of optical pulses with normally dispersive fiber-based devices

2018

International audience; We present a general method to determine the parameters of nonlinear pulse shaping systems based on pulse propagation in a normally dispersive fiber that are required to achieve the generation of pulses with various specified temporal properties. The nonlinear shaping process is reduced to a numerical optimization problem over a three-dimensional space, where the intersections of different surfaces provide the means to quickly identify the sets of parameters of interest. We also show that the implementation of a machine-learning strategy can efficiently address the multi-parameter optimization problem being studied.

Universal soliton pattern formations in passively mode-locked fiber lasers

2011

International audience; We investigate multiple-soliton pattern formations in a figure-of-eight passively mode-locked fiber laser. Operation in the anomalous dispersion regime with a double-clad fiber amplifier allows generation of up to several hundreds of solitons per round trip. We report the observation of remarkable soliton distributions: soliton gas, soliton liquid, soliton polycrystal, and soliton crystal, thus indicating the universality of such complexes.

Managing crop nitrogen and soil dynamics

2001

Despite extensive research grain legume seed protein content and yield remains low and unstable. Grain legume performances in the cropping system are highly dependent upon N nutrition of the crop relying on root assimilation of soil N in combination with symbiotic fixation of atmospheric dinitrogen. In order to improve the competitive ability of grain legumes for growth resources an enlargement of the crop surface area production in combination with a judicious management of both inputs and N acquisition (and allocation to the harvested organs) is needed. Competitive ability implies to take into account economical constraints and the crop production effect on the environment, reducing the a…

In vitro biotechnology approaches now available for ‘beautiful’ vavilovia (Vavilovia formosa)

2014

BAP Pôle GEAPSI; Efficient in vitro propagation of Vavilovia formosa, plant regeneration from callus, protoplast isolation and culture to differentiated callus of V.formosa were developed and its relative nuclear DNA content by flow cytometry was established. The summation of biotechnology tools now available should foster evolutionary studies on the tribe Fabeae and, intime, V.formosa could be come a potential source of novel agronomic adaptive traits.

Guidance of surface elastic waves along a linear chain of pillars

2016

International audience; The propagation of surface elastic waves, or surface phonons, is considered along a linear and periodic chain of cylindrical pillars sitting on a semi-infinite solid substrate. A variety of guided modes, some of them exhibiting a very low group velocity, are shown to exist at frequencies close to the resonance frequencies of the pillars. Although the pillar diameter is typically smaller than half the relevant wavelength, lateral radiation on the surface is found to be canceled. Surface guidance is explained by the hybridization of the resonating pillars with the continuum of elastic waves of the substrate.

ANTHER CULTURE TECHNIQUE FOR BREEDING AND PROPAGATION IN CITRUS AND IN OTHER MEDITERRANEAN FRUIT TREES

2011

Measurement of haemodynamics of exercising and non-exercising vastus lateralis muscle with hybrid diffuse optics

2016

We present simultaneous diffuse correlation spectroscopy (DCS) and time resolved spectroscopy (TR NIRS) measurements on exercising and non-exercising vastus lateralis muscle. We discuss the results at two different exercise levels.

Localization-Free Power Cartography

2018

Author's accepted manuscript (postprint). © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Spectrum cartography constructs maps of metrics such as channel gain or received signal power across a geographic area of interest using measurements of spatially distributed sensors. Applications of these maps include network planning, interference coordination, power con…

Fusion of CNN and sparse representation for threat estimation near power lines and poles infrastructure using aerial stereo imagery

2021

Abstract Fires or electrical hazards and accidents can occur if vegetation is not controlled or cleared around overhead power lines, resulting in serious risks to people and property and significant costs to the community. There are numerous blackouts due to interfering the trees with the power transmission lines in hilly and urban areas. Power distribution companies are facing a challenge to monitor the vegetation to avoid blackouts and flash-over threats. Recently, several methods have been developed for vegetation monitoring; however, existing methods are either not accurate or could not provide better disparity map in the textureless region. Moreover, are not able to handle depth discon…