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Femtosecond nonlinear losses in multimode optical fibers

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Photonics Research 2021年第12期9卷 2443-2453页

作者： MARIO FERRARO FABIO MANGINI MARIO ZITELLI ALESSANDRO TONELLO ANTONIO DE LUCA vincent couderc STEFAN WABNITZ Department of Information Engineering Electronicsand TelecommunicationsSapienza University of RomeVia Eudossiana 1800184 RomeItaly Department of Information Engineering University of BresciaVia Branze 3825123 BresciaItaly Universitéde Limoges XLIMUMR CNRS 7252123 Avenue A.Thomas87060 LimogesFrance Physics Department University of CalabriaI-87036 Arcavacata di RendeCSItaly CNR Nanotec-Institute of Nanotechnology S.S.CosenzaI-87036 RendeCSItaly CNR-INO Istituto Nazionale di OtticaVia Campi Flegrei 34I-80078 PozzuoliNAItaly

Multimode optical fibers are attracting a growing interest for their capability to transport high-power laser beams,coupled with novel nonlinear optics-based ***,optical fiber breakdown occurs when beam intensities exceed a certain critical *** breakdown associated with irreversible modifications of the refractive index,triggered by multiphoton absorption,has been largely exploited for fiber material *** we show that,for light beam intensities slightly below the breakdown threshold,nonlinear absorption strongly affects the dynamics of a propagating beam as *** experimentally analyze this subthreshold regime and highlight the key role played by spatial self-imaging in graded-index fibers for enhancing nonlinear optical *** characterize the nonlinear power transmission properties of multimode fibers for femtosecond pulses propagating in the near-infrared spectral *** show that an effective N-photon absorption analytical model is able to describe the experimental data well.

关键词： breakdown Femto fibers

Spatiotemporal mode decomposition of ultrashort pulses in linear and nonlinear graded-index multimode fibers

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Photonics Research 2023年第5期11卷 750-756页

作者： MARIO ZITELLI vincent couderc MARIO FERRARO FABIO MANGINI PEDRO PARRA-RIVAS YIFAN SUN STEFAN WABNITZ Department of Information Engineering Electronics and TelecommunicationsUniversitàdegli Studi di Roma Sapienza00184 RomeItaly Universitéde Limoges XLIMUMR CNRS 725287060 LimogesFrance CNR-INO Istituto Nazionale di Ottica80078 PozzuoliItaly

We develop a spatiotemporal mode decomposition technique to study the spatial and temporal mode power distribution of ultrashort pulses in long spans of graded-index multimode fiber,for different input laser *** find that the beam mode power content in the dispersive pulse propagation regime can be described by the Bose-Einstein law,as a result of the process of power diffusion from linear and nonlinear mode coupling among nondegenerate mode *** the soliton regime,the output mode power distribution approaches the Rayleigh-Jeans law.

关键词： ultrashort multimode mode

GaAs-chip-based mid-infrared supercontinuum generation

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Light(Science & Applications) 2023年第11期12卷 2443-2450页

作者： Geoffroy Granger Myriam Bailly Hugo Delahaye Cristian Jimenez Idris Tiliouine Yann Leventoux Jean-Christophe Orlianges vincent couderc Bruno Gérard Rezki Becheker Said Idlahcen Thomas Godin Ammar Hideur Arnaud Grisard Eric Lallier Sébastien Février Universitéde Limoges XLIM UMR CNRS 7252 123 Av.A.Thomas87060 LimogesFrance Thales Research&Technology 1 Av.Augustin Fresnel91767 Palaiseau CedexFrance III-V Lab 1 Av.Augustin Fresnel91767 Palaiseau CedexFrance CORIA(UMR 6614) CNRS-INSA Rouen-Universitéde Rouen NormandieNormandie UniversitéSaint-Etienne du RouvrayFrance

The mid-infrared spectral region opens up new possibilities for applications such as molecular spectroscopy with high spatial and frequency *** example,the mid-infrared light provided by synchrotron sources has helped for early diagnosis of several ***,alternative light sources at the table-top scale would enable better access to these state-of-the-art characterizations,eventually speeding up research in biology and *** supercontinuum generation in highly nonlinear waveguides pumped by compact fiber lasers represents an appealing alternative to ***,we introduce orientation-patterned gallium arsenide waveguides as a new versatile platform for mid-infrared supercontinuum *** and fiber-based pump lasers are optimized in tandem to allow for the group velocities of the signal and the idler waves to match near the degeneracy *** configuration exacerbates supercontinuum generation from 4 to 9μm when waveguides are pumped at 2750 nm with few-nanojoule energy *** brightness of the novel mid-infrared source exceeds that of the thirdgeneration synchrotron source by a factor of *** also show that the nonlinear dynamics is strongly influenced by the choice of waveguide and laser parameters,thus offering an additional degree of freedom in tailoring the spectral profile of the generated *** an approach then opens new paths for high-brightness mid-infrared laser sources development for high-resolution spectroscopy and ***,thanks to the excellent mechanical and thermal properties of the waveguide material,further power scaling seems feasible,allowing for the generation of watt-level ultra-broad frequency combs in the mid-infrared.

关键词： waveguide pumped pump

Additive neurorestorative effects of exercise and docosahexaenoic acid intake in a mouse model of Parkinson’s disease

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Neural Regeneration Research 2025年第2期20卷 574-586页

作者： Olivier Kerdiles Méryl-Farelle Oye Mintsa Mi-mba Katherine Coulombe Cyntia Tremblay vincentÉmond Martine Saint-Pierre Clémence Rouxel Line Berthiaume Pierre Julien Francesca Cicchetti Frédéric Calon Facultéde pharmacie UniversitéLaval1050 Avenue de la MédecineQuebecQCCanada Axe Neuroscience Centre de recherche du CHU de Québec-UniversitéLaval(Pavillon CHUL)2705 Boulevard LaurierQuebecQCCanada Institute of Nutrition and Functional Foods QuebecQCCanada Optinutribrain International Associated Laboratory(NutriNeuro FranceINAFCanada)QuebecQCCanada Axe Endocrinologie et Néphrologie Centre de recherche du CHU de Québec-UniversitéLavalQuebecQCCanada Département de Médecine Facultéde MédecineUniversitéLavalQuebecQCCanada Département de Psychiatrie et Neurosciences Facultéde MédecineQuebecQCCanada

There is a need to develop interventions to slow or reverse the degeneration of dopamine neurons in Parkinson’s disease after *** that preclinical and clinical studies suggest benefits of dietary n-3 polyunsaturated fatty acids,such as docosahexaenoic acid,and exercise in Parkinson’s disease,we investigated whether both could synergistically interact to induce recovery of the dopaminergic ***,mice received a unilateral stereotactic injection of 6-hydroxydopamine into the striatum to establish an animal model of nigrostriatal *** weeks after lesion,animals were fed a docosahexaenoic acid-enriched or a control diet for the next 8 *** this period,the animals had access to a running wheel,which they could use or *** acid treatment,voluntary exercise,or the combination of both had no effect on(i)distance traveled in the open field test,(ii)the percentage of contraversive rotations in the apomorphine-induction test or(iii)the number of tyrosine-hydroxylase-positive cells in the substantia nigra pars ***,the docosahexaenoic acid diet increased the number of tyrosine-hydroxylase-positive terminals and induced a rise in dopamine concentrations in the lesioned *** to docosahexaenoic acid treatment or exercise alone,the combination of docosahexaenoic acid and exercise(i)improved forelimb balance in the stepping test,(ii)decreased the striatal DOPAC/dopamine ratio and(iii)led to increased dopamine transporter levels in the lesioned *** present results suggest that the combination of exercise and docosahexaenoic acid may act synergistically in the striatum of mice with a unilateral lesion of the dopaminergic system and provide support for clinical trials combining nutrition and physical exercise in the treatment of Parkinson’s disease.

关键词： 6-hydroxydopamine dopamine dopamine transporter exercise neurorestoration Parkinson’s disease polyunsaturated fatty acids omega-3

Tourism Developments Increase Tsunami Disaster Risk in Pangandaran, West Java, Indonesia

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International Journal of Disaster Risk Science 2021年第5期12卷 764-769页

作者： vincent Nijman Department of Social Sciences Oxford Brookes UniversityOxford OX30BP.United Kingdom

On 17 July 2006,the tourist resort of Pangandaran on Java’s south coast was hit by a tsunami,resulting in 413 fatalities and severe damage to *** tsunami resulted in major rebuilds with a focus on mass *** of the impact of a future tsunami focussed on building development and suggest limited change since *** article presents a case study on the development of(largely domestic)tourism in Pangandaran and how this has increased the tsunami disaster *** numbers were stable at about 900,000 visitors a year prior to the tsunami,down to slightly over 250,000 visitors a year in its aftermath,and from 2007 onwards numbers are doubling every three years to about 4 million visitors in *** increase has been most pronounced during *** to 2006,Pangandaran was characterized by wooden structures and one-and two-story buildings of clay-brick masonry;by 2019,14 three to sixstory hotels have been erected along the *** many more visitors,most of whom are unfamiliar with tsunami risks,and shelter facilities for less than a quarter of visitors during peak times,future impacts and the potential cost to life are considerably higher now than in 2006,especially if a tsunami were to hit over a *** tourists upon arrival and throughout their stay should be better informed about the risks of tsunamis,and of the location of tsunami shelters and evacuation routes.

关键词： Disaster resilience Effective warning Indonesia Risk mitigation Tourism Tsunami

Strain and stress analysis on Zn multicrystal film by XRD method

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中国有色金属学会会刊：英文版 2006年第B2期16卷 735-738页

作者： vincent JI LIM UMR CNRS8006ENSAM 151Boulevard de I'Hopital75013 ParisFrance

A new method was denonstrated to determine stress in a single crystal for multicrystal material and this new method could be specially applied for any symmetric crystalline systems. The strain tensor e was determined by the change of the metric tensor G before the initial state and after the deformed state in the crystal reference system. Then stress tensor at grain scale was calculated by the HOOK's law. The stress evaluations were carried out in coarse grains of a thin galvanized coating on a steel substrate during tensile loading. This makes it possible to link the microstructure evolution to the elastic heterogeneity at grain scale or between the grains.

关键词：锌多晶膜单晶应力应变分析 XRD法锌镀层

Multicomponent flow modeling

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Science China Mathematics 2012年第1期55卷 285-308页

作者： GIOVANGIGLI vincent CMAP-CNRS Ecole

We present multicomponent flow models derived from the kinetic theory of gases and investigate the symmetric hyperbolic-parabolic structure of the resulting system of partial differential *** address the Cauchy problem for smooth solutions as well as the existence of deflagration waves,also termed anchored *** further discuss related models which have a similar hyperbolic-parabolic structure,notably the SaintVenant system with a temperature equation as well as the equations governing chemical equilibrium *** next investigate multicomponent ionized and magnetized flow models with anisotropic transport fluxes which have a different mathematical *** finally discuss numerical algorithms specifically devoted to complex chemistry flows,in particular the evaluation of multicomponent transport properties,as well as the impact of multicomponent transport.

关键词： multicomponent reactive flow Cauchy problem deflagration wave multicomponent transport

Experimental study of path planning problem using EMCOA for a holonomic mobile robot

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Journal of Systems Engineering and Electronics 2021年第6期32卷 1450-1462页

作者： MOHSENI Alireza DUCHAINE vincent WONG Tony Department of System Engineering École de Technologie SupérieureMontreal QC H3C 1K3Canada

In this paper,a comparative study of the path planning problem using evolutionary algorithms,in comparison with classical methods such as the A*algorithm,is presented for a holonomic mobile *** configured navigation system,which consists of the integration of sensors sources,map formatting,global and local path planners,and the base controller,aims to enable the robot to follow the shortest smooth path ***-based mapping is used for scoring paths efficiently,allowing the determination of collision-free trajectories from the initial to the target *** work considers the evolutionary algorithms,the mutated cuckoo optimization algorithm(MCOA)and the genetic algorithm(GA),as a global planner to find the shortest safe path among others.A non-uniform motion coefficient is introduced for MCOA in order to increase the performance of this algorithm.A series of experiments are accomplished and analyzed to confirm the performance of the global planner implemented on a holonomic mobile *** results of the experiments show the capacity of the planner framework with respect to the path planning problem under various obstacle layouts.

关键词： holonomic robot path planning evolutionary algorithm(EA)

Scattering and diffraction of plane P-waves in a 2-D elastic half-space Ⅱ：shallow arbitrary shaped canyon

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Earthquake Engineering and Engineering Vibration 2017年第3期16卷 459-485页

作者： Heather P.Brandow vincent Lee Civil and Environmental Engineering University of Southern California Los Angeles 90089 United States

Scattering and Diffraction of elastic in-plane P-and SV-waves by a surface topography such as an elastic canyon at the surface of a half-space is a classical problem which has been studied by earthquake engineers and strong-motion seismologists for over forty years. The case of out-of-plane SH waves on the same elastic canyon that is semi-circular in shape on the half-space surface is the first such problem that was solved by analytic closed form solutions over forty years ago by Trifunac. The corresponding case of in-plane P-and SV-waves on the same circular canyon is a much more complicated problem because, the in-plane P-and SV-scattered waves have different wave speeds and together they must have zero normal and shear stresses at the half-space surface. It is not until recently in 2014 that analytic solution for such problem is found by the author in the work of Lee and Liu. This paper uses the technique of Lee and Liu of defining these stress-free scattered waves to solve the problem of the scattered and diffraction of these in-plane waves on an almost-circular surface canyon that is arbitrary in shape.

关键词： diffraction elastic P-waves SV-waves weighted-residual method arbitrary-shaped canyon