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Time-consistent pension policy with minimum guarantee and sustainability constraint

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Probability, Uncertainty and Quantitative Risk 2024年第1期9卷 35-64页

作者： Caroline Hillairet Sarah Kaakar Mohamed Mrad CREST UMR CNRS 9194ENSAEInstitut Polytechnique de ParisFrance LMM Institut du Risque et de I'AssuranceLe Mans UniversiteFrance LAGA UMR CNRS 7539Universite Sorbonne Paris NordFrance

This paper proposes and investigates an optimal pair investment/pension policy for a pay-as-you-go(PAYG)pension *** social planner can invest in a buffer fund in order to guarantee a minimal pension *** model aims at taking into account complex dynamic phenomena such as the demographic risk and its evolution over time,the time and age dependence of agents preferences,and financial *** preference criterion of the social planner is modeled by a consistent dynamic utility defined on a stochastic domain,which incorporates the heterogeneity of overlapping generations and its evolution over *** preference criterion and the optimization problem also incorporate sustainability,adequacy and fairness *** paper designs and solves the social planner's dynamic decision criterion,and computes the optimal investment/pension policy in a general framework.A detailed analysis for the case of dynamic power utilities is provided.

关键词： Consistent dynamic utility PAYG pension policy Sustainability and actuarial fairness Demographic and financial risk sharing Stochastic control

Piezoelectric resonant ice protection systems–Part1/2:Prediction of power requirement for de-icing a NACA 0024 leading edge

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Chinese Journal of Aeronautics 2024年第3期37卷 92-103页

作者： Valerian PALANQUE Jason POTHIN Vale′rie POMMIER-BUDINGER Marc BUDINGER Institut Clement Ader University of ToulouseINSAISAE-SUPAEROMINES ALBIUPSCNRSToulouse 31055France ISAE-SUPAERO University of Toulouse10 Avenue Edouard BelinToulouse 31055France

This paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing *** method is based on a coupled electro-mechanical finite element analysis which enables the fast computation of the modes of resonance of interest to de-ice curved surfaces and the estimation of the input voltage and current required for a given configuration(defined by its mode,actuator location,ice deposit,etc.).Eventually,the electric power to be supplied can be also *** method is applied to a NACA 0024 leading edge equipped with piezoelectric ***,two extension modes are analyzed and compared with respect to their efficiency and power ***,tests are carried out in an icing tunnel to verify the effectiveness of the piezoelectric ice protection system and the predictions of the maximal required *** system allows de-icing the leading edge in less than 2 s for a glaze ice deposit.

关键词： Ice protection system Piezoelectric Resonance mode Ice fracture Leading edge de-icing

Piezoelectric resonant ice protection systems-Part 2/2:Evaluation of benefits at aircraft level

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Chinese Journal of Aeronautics 2024年第6期37卷 50-63页

作者： Valerian PALANQUE Thomas PLANES Pommier-Budinger VALERIE Budinger MARC Delbecq SCOTT Institut Clement Ader(ICA) INSAISAE-SUPAEROMINES ALBIUPSCNRSUniversity of Toulouse31400 ToulouseFrance Federation ENAC ISAE-SUPAERO ONERA University of Toulouse31400 ToulouseFrance

Piezoelectric resonant de-icing systems are attracting great *** paper aims to assess the implementation of these systems at the aircraft *** article begins with the model to compute the power requirement of a piezoelectric resonant de-icing system sized from the prototype detailed in Part 1/2 of this *** the mass,drag,and fuel consumption of this system and the subcomponents needed for its implementation are *** features of a piezoelectric resonant de-icing system are finally computed for aircraft similar to Airbus A320 aircraft and aircraft of different categories(Boeing 787,ATR 72 and TBM 900)and compared with the existing thermal and mechanical ice protection systems.A sensitivity analysis of the main key sizing parameters of the piezoelectric de-icing system is also performed to identify the main axes of improvement for this *** study shows the potential of such ice protection *** particular,for the realistic input parameters chosen in this work,the electro-mechanical solution can provide a 54% reduction in terms of mass and a 92% reduction in terms of power consumption for an A320 aircraft architecture,leading to a 74% decrease in the associated fuel consumption compared to the actual air bleed system.

关键词： Ice protection system De-icing Piezoelectric Electro-mechanical system Power Fuel consumption

The Wave Front Set Correspondence for Dual Pairs with One Member Compact

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Acta Mathematica Sinica,English Series 2024年第3期40卷 823-869页

作者： Mark MCKEE Angela PASQUALE Tomasz PRZEBINDA Hammond Lane ProvidenceUT 84332USA Universite de Lorraine CNRSIECLF-57000 MetzFrance Department of Mathematics University of OklahomaNormanOK 73019USA

Let W be a real symplectic space and(G,G')an irreducible dual pair in Sp(W),in the sense of Howe,with G *** G be the preimage of G in the metaplectic group Sp(W).Given an irreducible unitary representation II of G that occurs in the restriction of the Weil representation to G,let On denote its *** prove that,for a suitable embedding T of Sp(W)in the space of tempered distributions on W,the distribution T(On)admits an asymptotic limit,and the limit is a nilpotent orbital *** an application,we compute the wave front set of II',the representation of G dual to II,by elementary means.

关键词： Reductive dual pairs Howe duality Weil representation wave front set orbital integrals

Optical probing of ultrafast laser-induced solid-to-overdense-plasma transitions

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Light(Science & Applications) 2024年第5期13卷 973-984页

作者： Yasmina Azamoum Georg Alexander Becker Sebastian Keppler Guillaume Duchateau Stefan Skupin Mickael Grech Fabrice Catoire Sebastian Hell Issa Tamer Marco Hornung Marco Hellwing Alexander Kessler Franck Schorcht Malte Christoph Kaluza GSI Helmholtzzentrum für Schwerionenforschung Planckstr.164291 DarmstadtGermany. Helmholtz Institute Jena Fröbelstieg 307743 JenaGermany. Institute of Optics and Quantum Electronics Friedrich-SchillerUniversität JenaMax-Wien-Platz 107743 JenaGermany. CEA-CESTA 15 Avenue des SablièresCS6000133116 Le BarpCedexFrance Institut Lumière Matière UMR 5306-CNRSUniversitéde Lyon 169622 VilleurbanneFrance. LULI CNRSCEASorbonne UniversitéInstitut Polytechnique de ParisPalaiseauFrance. Universitéde Bordeaux-cnrs-CEA CELIAUMR 5107 TalenceFrance

Understanding the solid target dynamics resulting from the interaction with an ultrashort laser pulse is a challenging fundamental multi-physics problem involving atomic and solid-state physics,plasma physics,and laser *** of the initial interplay of the underlying processes is essential to many applications ranging from lowpower laser regimes like laser-induced ablation to high-power laser regimes like laser-driven ion *** the properties of the so-called pre-plasma formed as the laser pulse’s rising edge ionizes the target is complicated from the theoretical and experimental point of view,and many aspects of this laser-induced transition from solid to overdense plasma over picosecond timescales are still open *** the one hand,laser-driven ion acceleration requires precise control of the pre-plasma because the efficiency of the acceleration process crucially depends on the target properties at the arrival of the relativistic intensity peak of the *** the other hand,efficient laser ablation requires,for example,preventing the so-called“plasma shielding”.By capturing the dynamics of the initial stage of the interaction,we report on a detailed visualization of the pre-plasma formation and ***-thin diamond-like carbon foils are shown to transition from solid to plasma during the laser rising edge with intensities<10^(16)W/cm^(2).Single-shot near-infrared probe transmission measurements evidence sub-picosecond dynamics of an expanding plasma with densities above 10^(23)cm^(−3)(about 100 times the critical plasma density).The complementarity of a solid-state interaction model and kinetic plasma description provides deep insight into the interplay of initial ionization,collisions,and expansion.

关键词： laser acceleration solid

Prompt neutron emission in ^(250)No spontaneous fission associated with ground and isomeric state decays

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Chinese Physics C 2024年第6期48卷 112-117页

作者： R.S.Mukhin A.V.Isaev A.V.Andreev M.L.Chelnokov V.I.Chepigin H.M.Devaraja I.N.Izosimov A.A.Kuznetsova O.N.Malyshev A.G.Popeko Yu.A.Popov A.Rahmatinejad B.Sailaubekov T.M.Shneidman E.A.Sokol A.I.Svirikhin M.S.Tezekbayeva M.A.Bychkov A.V.Yeremin O.Dorvaux B.Gall K.Kessaci K.Hauschild A.Lopez-Martens Joint Institute for Nuclear Research Dubna141980Russia Dubna State University Dubna141982Russia Institute of Nuclear Physics Almaty050032Kazakhstan L.N.Gumilyov Eurasian National University Astana010008Kazakhstan Kazan Federal University Kazan420008Russia Universitéde Strasbourg CNRSStrasbourg67000France IJCLab IN2P3-CNRSUniversitéParis-SaclayOrsay91400France

The complete-fusion reaction^(204)Pb(^(48)Ca,2n)^(250)No was used to study two activities of^(250)No with distinct half-lives.A total of 1357 events were observed in the SFiNx neutron detection *** average number of neutrons emitted per spontaneous fission of^(250)No was determined to be(4.1±0.1).The unusually symmetrical shape of the prompt neutron multiplicity distribution was restored and presented for the first *** tests were performed to compare the prompt neutron multiplicity distributions associated with the ground state and K-isomer state decays.

关键词： spontaneous fission prompt neutrons actinide

Collisionless shock acceleration of protons in a plasma slab produced in a gas jet by the collision of two laser-driven hydrodynamic shockwaves

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Matter and Radiation at Extremes 2024年第2期9卷 12-25页

作者： J.-R.Marquès L.Lancia P.Loiseau P.Forestier-Colleoni M.Tarisien E.Atukpor V.Bagnoud C.Brabetz F.Consoli J.Domange F.Hannachi P.Nicolaï M.Salvadori B.Zielbauer LULI CNRSÉcole PolytechniqueCEASorbonne UniversitéInstitut Polytechnique de Paris91128 Palaiseau CedexFrance CEA DAMDIF91297 Arpajon CedexFrance UniversitéParis-Saclay CEALMCE91680 Bruyères-le-ChatelFrance CENBG CNRS-IN2P3Universitéde Bordeaux33175 Gradignan CedexFrance GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 164291 DarmstadtGermany University of Darmstadt Schloßgartenstr.764289 DarmstadtGermany ENEA Fusion and Technologies for Nuclear Safety Department C.R.FrascatiVia Enrico Fermi 45FrascatiRomeItaly CELIA Universitéde Bordeaux–CNRS–CEA33405 TalenceFrance UniversitéParis-Saclay CEALIDYL91191 Gif-sur-YvetteFrance

We have recently proposed a new technique of plasma tailoring by laser-driven hydrodynamic shockwaves generated on both sides of a gas jet[Marquès et al.,*** 28,023103(2021)].In a continuation of this numerical work,we study experimentally the influence of the tailoring on proton acceleration driven by a high-intensity picosecond laser in three cases:without tailoring,by tailoring only the entrance side of the picosecond laser,and by tailoring both sides of the gas *** tailoring,the acceleration is transverse to the laser axis,with a low-energy exponential spectrum,produced by Coulomb *** the front side of the gas jet is tailored,a forward acceleration appears,which is significantly enhanced when both the front and back sides of the plasma are *** forward acceleration produces higher-energy protons,with a peaked spectrum,and is in good agreement with the mechanism of collisionless shock acceleration(CSA).The spatiotemporal evolution of the plasma profile is characterized by optical shadowgraphy of a probe *** refraction and absorption of this beam are simulated by post-processing 3D hydrodynamic simulations of the plasma *** with the experimental results allows estimation of the thickness and near-critical density of the plasma slab produced by tailoring both sides of the gas *** parameters are in good agreement with those required for CSA.

关键词： acceleration hydrodynamic collision

Electronic engineering of Co-Ru diatomic sites and Ru nanoparticles for synergistic promotion of hydrogen evolution

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Nano Research 2024年第5期17卷 3714-3723页

作者： Wei Zhang Cong Li Yongyong Cao Jun-Yang Ji Zhao-Chen Li Zheng Niu Hongwei Gu Pierre Braunstein Jian-Ping Lang College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing 314001China Universitéde Strasbourg-cnrs Institut de Chimie(UMR 7177 CNRS)4 rue Blaise Pascal-CS 9003267081 StrasbourgFrance

The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER *** the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the *** unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline *** work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.

关键词： Co-Ru diatomic sites Ru nanoparticles multiple active sites synergistic effect hydrogen evolution reaction

Probabilistic Global Maximum Power Point Tracking Algorithm for Continuously Varying Partial Shading Conditions on Autonomous PV Systems

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Energy and Power Engineering 2024年第1期16卷 21-42页

作者： Kha Bao Khanh Cao Vincent Boitier LAAS-cnrs University of Toulouse Toulouse France

A photovoltaic (PV) string with multiple modules with bypass diodes frequently deployed on a variety of autonomous PV systems may present multiple power peaks under uneven shading. For optimal solar harvesting, there is a need for a control schema to force the PV string to operate at global maximum power point (GMPP). While a lot of tracking methods have been proposed in the literature, they are usually complex and do not fully take advantage of the available characteristics of the PV array. This work highlights how the voltage at operating point and the forward voltage of the bypass diode are considered to design a global maximum power point tracking (GMPPT) algorithm with a very limited global search phase called Fast GMPPT. This algorithm successfully tracks GMPP between 94% and 98% of the time under a theoretical evaluation. It is then compared against Perturb and Observe, Deterministic Particle Swarm Optimization, and Grey Wolf Optimization under a sequence of irradiance steps as well as a power-over-voltage characteristics profile that mimics the electrical characteristics of a PV string under varying partial shading conditions. Overall, the simulation with the sequence of irradiance steps shows that while Fast GMPPT does not have the best convergence time, it has an excellent convergence rate as well as causes the least amount of power loss during the global search phase. Experimental test under varying partial shading conditions shows that while the GMPPT proposal is simple and lightweight, it is very performant under a wide range of dynamically varying partial shading conditions and boasts the best energy efficiency (94.74%) out of the 4 tested algorithms.

关键词： Photovoltaic PV Global Maximum Power Point Tracking GMPPT Fast Varying Partial Shading Conditions Autonomous PV Systems GMPPT Review