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Science China Mathematics 2024年第3期67卷 627-646页

作者： Hui Xiao Ion Grama Quansheng Liu Institut fur Mathematik und Angewandte Informatik Universitat HildesheimHildesheim 31141Germany Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China LMBA Universite Bretagne SudCNRS UMR 6205Vannes F-56000France

Let(g_(n))_(n≥1) be a sequence of independent and identically distributed positive random d×d matrices and consider the matrix product G_(n)=g_(n)…g_*** suitable conditions,we establish the Berry-Esseen bounds on the rate of convergence in the central limit theorem and Cramer-type moderate deviation expansions,for any matrix norm ‖G_(n)‖ of G_(n),its entries G_(n)^(i,j) and its spectral radius ρ(G_(n)).Extended versions of their joint law with the direction of the random walk G_(n)x are also established,where x is a starting point in the unit sphere of R~d.

关键词： Berry-Esseen bound Cramér-type moderate deviation product of random matrices operator norm entry spectral radius

Recycled graphite for more sustainable lithium-ion batteries

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Carbon Energy 2024年第5期6卷 15-24页

作者： Mayokun Olutogun Anna Vanderbruggen Christoph Frey Martin Rudolph Dominic Bresser Stefano Passerini Helmholtz Institute Ulm(HIU) Ulm Germany karlsruhe Institute of Technology(KIT) KarlsruheGermany Helmholtz Zentrum Dresden-Rossendorf(HZDR) Helmholtz Institute Freiberg for Resource Technology(HIF)FreibergGermany ProGraphite GmbH UntergriesbachGermany Chemistry Department Sapienza University of RomeRomeItaly

The demand for lithium-ion batteries(LIBs)is driven largely by their use in electric vehicles,which is projected to increase dramatically in the *** great success,however,urgently calls for the efficient recycling of LIBs at the end of their ***,we describe a froth flotation-based process to recycle graphite—the predominant active material for the negative electrode—from spent LIBs and investigate its reuse in newly assembled *** has been found that the structure and morphology of the recycled graphite are essentially unchanged compared to pristine commercial anode-grade graphite,and despite some minor impurities from the recycling process,the recycled graphite provides a remarkable reversible specific capacity of more than 350 mAh g^(−1).Even more importantly,newly assembled graphite‖NMC532 cells show excellent cycling stability with a capacity retention of 80%after 1000 cycles,that is,comparable to the performance of reference full cells comprising pristine commercial graphite.

关键词： anode graphite lithium-ion battery recycling sustainability

Wear dependent virtual flow rate sensor for progressing cavity pumps with deformable stator

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Petroleum Science 2024年第2期21卷 1346-1353页

作者： Jens Müller Sebastian Leonow Johannes Schulz Christian Hansen Martin Monnigmann Ruhr-universitat Bochum Universit atsstraûe 150Bochum44801Germany SEEPEX GmbH Scharnh olzstraûe 344Bottrop46240Germany

This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation.

关键词： Backflow Progressing cavity pump Virtual sensor Wear

ON CONE D.C. OPTIMIZATION AND CONJUGATE DUALITY

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Chinese Annals of Mathematics,Series B 2003年第4期24卷 521-528页

作者： M.SEMU Institut fut Statistik und Mathematische Wirtschaftstheorie Universitat Karlsruhe76128 KarlsruheGermany.

This paper derives first order necessary and sufficient conditions for unconstrained coned.c. Programming problems where the underlined space is partially ordered with respect to acone. These conditions are given in terms of directional derivatives and subdifferentials of thecomponent functions. Moreover, conjugate duality for cone d.c. Optimization is discussed andweak duality theorem is proved in a more general partially ordered linear topological vectorspace (generalizing the results in [11]).

关键词：锥d.c.最优化共轭对偶弱对偶定理次梯度多目标优化方向导数

BACKWARD ERROR ANALYSIS OF SYMPLECTIC INTEGRATORS FOR LINEAR SEPARABLE HAMILTONIAN SYSTEMS

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Journal of Computational Mathematics 2002年第5期20卷 449-460页

作者： PeterGrtz Institut fur Praktische Mathematik Universitat Karlsruhe Englerstrabe 德国 Karlsruhe 276128

Presents a study that analyzed the symplecticness, stability and asymptotic of Runge-Kutta, partitioned Runge-Kutta, and Runge-Kutta-Nystr ? m methods applied to linear Hamiltonian systems. Numerical representation of the problem; Results in connection to P-stability; Details of the application of backward error analysis in the study.

关键词： Hamiltonian systems Backward error analysis Symplectic integrators.

Optimizing laser coupling,matter heating,and particle acceleration from solids using multiplexed ultraintense lasers

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Matter and Radiation at Extremes 2024年第4期9卷 16-28页

作者： Weipeng Yao Motoaki Nakatsutsumi Sébastien Buffechoux Patrizio Antici Marco Borghesi Andrea Ciardi Sophia N.Chen Emmanuel d’Humières Laurent Gremillet Robert Heathcote Vojtech Horny Paul McKenna Mark N.Quinn Lorenzo Romagnani Ryan Royle Gianluca Sarri Yasuhiko Sentoku Hans-Peter Schlenvoigt Toma Toncian Olivier Tresca Laura Vassura Oswald Willi Julien Fuchs LULI-CNRS CEASorbonne UniversitéEcole PolytechniqueInstitut Polytechnique de ParisF-91128 Palaiseau CedexFrance Sorbonne Université Observatoire de ParisUniversité PSLCNRSLERMAF-75005 ParisFrance INRS-EMT 1650 BoulLionel-BouletVarennesQuebec J3X 1S2Canada Center for Plasma Physics School of Mathematics and PhysicsQueen’s University BelfastBelfast BT71NNUnited Kingdom “Horia Hulubei”National Institute for Physics and Nuclear Engineering 30 Reactorului StreetRO-077125 Bucharest-MagureleRomania University of Bordeaux Centre Lasers Intenses et ApplicationsCNRSCEAUMR 5107F-33405 TalenceFrance CEA DAMDIFF-91297 ArpajonFrance Université Paris-Saclay CEALMCE91680 Bruyères-le-ChatelFrance Central Laser Facility STFC Rutherford Appleton LaboratoryDidcotUnited Kingdom SUPA Department of PhysicsUniversity of StrathclydeGlasgow G40NGUnited Kingdom Department of Physics University of NevadaRenoNevada 89557USA Institute of Laser Engineering Osaka University2-6 YamadaokaSuitaOsaka 565-0871Japan Institut fur Laser und Plasmaphysik Heinrich Heine Universitat DusseldorfDusseldorfGermany

Realizing the full potential of ultrahigh-intensity lasers for particle and radiation generation will require multi-beam arrangements due to technology ***,we investigate how to optimize their coupling with solid ***,we show that overlapping two intense lasers in a mirror-like configuration onto a solid with a large preplasma can greatly improve the generation of hot electrons at the target front and ion acceleration at the target *** underlying mechanisms are analyzed through multidimensional particle-in-cell simulations,revealing that the self-induced magnetic fields driven by the two laser beams at the target front are susceptible to reconnection,which is one possible mechanism to boost electron *** addition,the resistive magnetic field generated during the transport of the hot electrons in the target bulk tends to improve their *** simulations also indicate that such effects can be further enhanced by overlapping more than two laser beams.

关键词： laser acceleration particle

Modeling of Long-Range Intra- and Inter-Species Charged Particle Collisions for PIC Simulations

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Communications in Computational Physics 2010年第5期7卷 877-903页

作者： D.D’Andrea C.-D.Munz R.Schneider Forschungszentrum karlsruhe-in der Helmholtz-Gemeinschaft Institut fur Kern-und EnergietechnikPF 3640D-76021 KarlsruheGermany Institut fur Aerodynamik und Gasdynamik Universitat StuttgartPfaffenwaldring 21D-70550 StuttgartGermany Forschungszentrum karlsruhe-in der Helmholtz-Gemeinschaft Institut fur Hochleistungsimpuls und MikrowellentechnikPF 3640D-76021 KarlsruheGermany

In this paper we present the modelling of elastic intra-species electron-electron and inter-species electron-ion scattering in a plasma on the basis of the FokkerPlanck collision *** into account the equivalence of this operator with a stochastic differential equation,we propose a Particle-in-Cell based approach for the numerical solution of the Fokker-Planck collision *** we will see,the introduced numerical concept allows the simulation of the collisional relaxation process in a fully self-consistent fashion.

关键词： Coulomb collisions in plasmas collisional relaxation Fokker-Planck equation stochastic differential equation particle-in-cell method

Shock Wave Smearing by Passive Control

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Journal of Thermal Science 2006年第1期15卷 43-47,42页

作者： Piotr DOERFFER Oskar SZULC Rainer BOHNING IMP PAN Fiszera 14 PL-80 952 Gdansk Poland ISL Universitat Karlsruhe Karlsruhe Germany

正常冲击波，在一个机翼上终止一个本地超声的区域，限制它的表演并且成为来源高加速冲动的噪音。使用被动控制瓦解被建议冲击波。这个方法获得的流动结构的细节数字地被学习。一个新边界条件被开发了，它的应用程序的结果在嘴流动对实... 详细信息

正常冲击波，在一个机翼上终止一个本地超声的区域，限制它的表演并且成为来源高加速冲动的噪音。使用被动控制瓦解被建议冲击波。这个方法获得的流动结构的细节数字地被学习。一个新边界条件被开发了，它的应用程序的结果在嘴流动对实验被验证。崩溃被证实了并且详细说明流动细节的分析的冲击波的方法被介绍。由渐渐的压缩的一个冲击波的替换完全改变高速度的来源它的减小的冲动的噪音和熊潜力。关键词接近音速的流动 - 冲击波边界层相互作用 - 被动控制 CLC 数字 O357.

关键词：跨音速流振波边界层交互作用被动控制机翼

Fabrication of micrometre-sized periodic gratings in free-standing metallic foils for laser-plasma experiments

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High Power Laser Science and Engineering 2022年第1期10卷 17-31页

作者： C.C.Gheorghiu M.Cerchez E.Aktan R.Prasad F.Yilmaz N.Yilmaz D.Popa O.Willi V.Leca Extreme Light Infrastructure-Nuclear Physics Horia Hulubei National Institute for Physics and Nuclear Engineering077125 MagureleRomania Institut fur Laser-und Plasmaphysik Heinrich-Heine-Universitat40225 DiisseldorfGermany

Engineered targets are expected to play a key role in future high-power laser experiments calling for joined, extensive knowledge in materials properties, engineering techniques and plasma physics. In this work, we propose a novel patterning procedure of self-supported 10 μm thick Au and Cu foils for obtaining micrometre-sized periodic gratings as targets for high-power laser applications. Accessible techniques were considered, by using cold rolling, electronbeam lithography and the Ar-ion milling process. The developed patterning procedure allows efficient control of the grating and foil surface on large area. Targets consisting of patterned regions of 450 μm × 450 μm, with 2 μm periodic gratings, were prepared on 25 mm × 25 mm Au and Cu free-standing foils, and preliminary investigations of the microtargets interacting with an ultrashort, relativistic laser pulse were performed. These test experiments demonstrated that,in certain conditions, the micro-gratings show enhanced laser energy absorption and higher efficiency in accelerating charge particle beams compared with planar thin foils of similar thickness.

关键词： laser driven plasmas on structured targets metallic foils micro-grating patterned targets

The contribution of small leaks in a baghouse filter to dust emission in the PM2.s range-A system approach

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Particuology 2017年第1期15卷 40-52页

作者： Oliver Kurtz Jorg Meyer Gerhard Kasper Institut for Mechanische Verfahrenstechnik und Mechanik Karlsruhe Institute of Technology 76131 Karlsruhe Germany Freudenberg Filtration Technologies 69465 WeinheimGermany.

The contribution of leakage in a baghouse filter （defined as a short circuit between the upstream and downstream sides of the filter） to the emission of fine particles is quantified in comparison to other dust emission sources, and the influence of key operating variables on overall system response is analyzed. The study was conducted on a well-maintained pilot-scale filter unit （9 bags of 500 g/m^2 calendered polyester needle felt; total surface area 4.2 m^2） operated in Ap-controlled mode over a range of pulsing intensities, with two types of test dust （one free-flowing and the other cohesive） at inlet concentrations of 10 and 30 g/m^3. Leaks included single holes between 0.5 and 4 mm diameter, intentionally placed in either the plenum plate or one of the filter bags, as well as seamlines from bag confectioning. Emissions were sep- arated by source into a transient contribution due to dust penetration through the filter bags after each cleaning pulse, and a continuous contribution from leaks. This separation was based on a novel method of data processing that relies on time-resolved concentration measurements with a specially calibrated optical particle counter. Tiny leaks on the order of 1 mm generated the same emission level as all the bags combined, and dominated continuous emissions. The equivalent leak cross section （leakage = media emission） was about 1 ppm of the total installed filter surface, independent of upstream dust concentra- tion. Leakage through open seamlines amounted to 75% of media emissions in case of free-flowing test dust. Leakage was restricted to aerodynamic diameters less than ~5 μm （roughly the PM2.s mass frac- tion）. For comparison, time-averaged mass penetration through conventional needle-felt media ranged from about 10^-5 to 10^-6, depending on cohesiveness of the particle material and pulse cleaning intensity, giving emission levels between about 0.02 and 0.2 mg/m^3 at the reference concentration of 10 R/m^2.

关键词： Air filtration Baghouse Pulse-cleaned filters Leaks PM2.5 Dust emission