694,026 research outputs found

    On fully nonlinear CR invariant equations on the Heisenberg group

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    AbstractIn this paper we provide a characterization of second order fully nonlinear CR invariant equations on the Heisenberg group, which is the analogue in the CR setting of the result proved in the Euclidean setting by A. Li and the first author in Li and Li (2003) [21]. We also prove a comparison principle for solutions of second order fully nonlinear CR invariant equations defined on bounded domains of the Heisenberg group and a comparison principle for solutions of a family of second order fully nonlinear equations on a punctured ball

    Structural and electrochemical characterization of xLi[Li1/3Mn2/3]O2·(1 - x)Li[Ni1/3Mn1/3Co1/3]O2 (0 ≤ x ≤ 0.9) as cathode materials for lithium ion batteries

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    A series of cathode materials with molecular notation of xLi[Li1/3Mn2/3]O2·(1 - x)Li[Ni1/3Mn1/3Co1/3]O2 (0 ≤ x ≤ 0.9) were synthesized by combination of co-precipitation and solid state calcination method. The prepared materials were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques, and their electrochemical performances were investigated. The results showed that sample 0.6Li[Li1/3Mn2/3]O2·0.4Li[Ni1/3Mn1/3Co1/3]O2 (x = 0.6) delivers the highest capacity and shows good capacity-retention, which delivers a capacity ∼250 mAh g-1 between 2.0 and 4.8 V at 18 mA g-1. © 2008 Elsevier B.V. All rights reserved

    Tour to China, Concert Nanjing, Concert Xi'an; recitals with Ma, L. (cellist), Yin, N. (violinist), Ju, Y. (pianist) Dong, L. (flautist), Ma Li, L. (flautist), Qiao Liang, Q. (flautist) in Nanjing performing Beethoven: Symphony No 1 arr Hummel ( Edition Grodd), Taira:Synchcronie, Bozza: Jour d ete Quartet; Koechlin: Sonata, Hosokawa: Kuroda Bushi Flute and in Xi'an with Dong, L. (flautist),, Gao, Q. (Flautist), Gao, Y. (Flautist), Zhang, K. (Flautist) .

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    Recitals with Ma, L. (cellist), Yin, N. (violinist), Ju, Y. (pianist) Dong, L. (flautist), Ma Li, L. (flautist), Qiao Liang, Q. (flautist) in Nanjing performing Beethoven: Symphony No 1 arr Hummel ( Edition Grodd), Taira:Synchcronie, Bozza: Jour d ete Quartet; Koechlin: Sonata, Hosokawa: Kuroda Bushi Flute and in Xi'an with Dong, L. (flautist),, Gao, Q. (Flautist), Gao, Y. (Flautist), Zhang, K. (Flautist) .Public concerts including world premier of Beethoven Symphony No 1 arr Hummel Edition Grodd, with Head of Strings Prof Ma and colleagues in Nanjing. In Xi'an performance with Head of Flutes Professor Gao. Repertoire: Beethoven: Symphony No 1 arr Hummel ( Edition Grodd), Taira:Synchcronie, Bozza: Jour d ete Quartet; Koechlin: Sonata, Hosokawa: Kuroda Bushi Flutehttp://www.xacom.edu.cn/info/1055/18653.ht

    Corrigendum to “Reliability assessment of generic geared wind turbines by GTST-MLD model and Monte Carlo simulation” (Renewable Energy (2015) 83 (222–233), (S0960148115003158), (10.1016/j.renene.2015.04.035))

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    The authors regret that the Order of Authors in this article published in November 2015 is incorrect. Thus, the objective of this Corrigendum is to re-establish the originally agreed Order of Authors, as described below. Order of Authors from published Article: Yan-Fu Li, PhD; Sebastien Valla; Enrico Zio, PhD. Corrected Order of Authors to implement with this Corrigendum: Sebastien Valla, Yan-Fu Li, PhD; Enrico Zio, PhD. The Corresponding author to contact for these changes are the Primary Author, Sebastien Valla (email below). The authors would like to apologise for any inconvenience caused

    Li, L. Y.

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    On the in-situ aqueous stability of an Mg-Li-(Al-Y-Zr) alloy: Role of Li

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    The aqueous stability of a corrosion resistant Mg-Li(-Al-Y-Zr)-alloy was investigated by combining in-situ confocal Raman Microscopy, Atomic Emission SpectroElectroChemistry, ex-situ Photoluminiscence Spectroscopy, Auger Electron Spectroscopy and Glow Discharge Optical Emission Spectroscopy. Li and Mg dissolved from visually intact anodic areas, leaving a Li-depleted metallic layer under approximately 100 nm thick Li-doped MgO. The transformation MgO→Mg(OH)2 was inhibited. Li2[Al2(OH)6]2·CO3·nH2O, LiAlO2, Y2O3 and Mg(OH)2 accumulated locally around active cathodic sites. New corrosion mechanism is proposed, which associates the improved corrosion resistance of Mg-Li alloys with an enhanced chemical stability and modified catalytic activity of MgO in presence of Li+

    Interfacial “Single-Atom-in-Defects” Catalysts Accelerating Li+ Desolvation Kinetics for Long-Lifespan Lithium-Metal Batteries

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    The lithium-metal anode is a promising candidate for realizing high-energy-density batteries owing to its high capacity and low potential. However, several rate-limiting kinetic obstacles, such as the desolvation of Li+ solvation structure to liberate Li+, Li0 nucleation, and atom diffusion, cause heterogeneous spatial Li-ion distribution and fractal plating morphology with dendrite formation, leading to low Coulombic efficiency and depressive electrochemical stability. Herein, differing from pore sieving effect or electrolyte engineering, atomic iron anchors to cation vacancy-rich Co1−xS embedded in 3D porous carbon (SAFe/CVRCS@3DPC) is proposed and demonstrated as catalytic kinetic promoters. Numerous free Li ions are electrocatalytically dissociated from the Li+ solvation complex structure for uniform lateral diffusion by reducing desolvation and diffusion barriers via SAFe/CVRCS@3DPC, realizing smooth dendrite-free Li morphologies, as comprehensively understood by combined in situ/ex situ characterizations. Encouraged by SAFe/CVRCS@3DPC catalytic promotor, the modified Li-metal anodes achieve smooth plating with a long lifespan (1600 h) and high Coulombic efficiency without any dendrite formation. Paired with the LiFePO4 cathode, the full cell (10.7 mg cm−2) stabilizes a capacity retention of 90.3% after 300 cycles at 0.5 C, signifying the feasibility of using interfacial catalysts for modulating Li behaviors toward practical applications

    Numerical Study of Whipple Shield's Spallation Failure Caused by Hypervelocity Impact at 8km/s

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    The spallation is a common phenomenon happening during the hypervelocity impact, especially in the high-velocity regime of the Whipple shield. Although the limitation of conventional launch techniques makes the hypervelocity impact experiment of high-velocity regime very expensive, fortunately, in recent years a series of experiments with impact velocity at 8km/s has been conducted, providing a reference of great value for the improvement of the numerical simulation method. As pulverization and spread of the projectile's debris plays an important role in the formation of spallation, the size of particles used in the numerical simulation of the destruction of the Whipple shield needs to be sufficiently small, resulting in the huge amount of calculation. For axisymmetric problems, the discretization method in the cylindrical coordinate system can be used to reduce the amount of calculation significantly, however, the calculation error will come out in the area near the symmetric axis, resulting in the wrong simulation of Whipple shield's failure mode. In this article, a new discretization method has been developed on the base of the staggered grid material point method. To overcome the calculation error in the nearby area of the symmetric axis, the shape function and the boundary condition are improved for the cylindrical coordinate system. Through the new discretization method coupled with the multi-phase equation of state, the spallation of the Whipple shield's backwall is clearly simulated, and agrees well with the recently conducted experiment. In addition, the failure mode of the Whipple shield in the high-velocity regime and the forming condition of backwall's spallation failure have been analyzed via the numerical simulation, offering references for the design of the spacecraft's protection structure

    The amoebal MAP kinase response to Legionella pneumophila is regulated by DupA

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    The amoeba Dictyostelium discoideum can support replication of Legionella pneumophila. Here we identify the dupA gene, encoding a putative tyrosine kinase/dual-specificity phosphatase, in a screen for D. discoideum mutants altered in allowing L. pneumophila intracellular replication. Inactivation of dupA resulted in depressed L. pneumophila growth and sustained hyperphosphorylation of the amoebal MAP kinase ERK1, consistent with loss of a phosphatase activity. Bacterial challenge of wild-type amoebae induced dupA expression and resulted in transiently increased ERK1 phosphorylation, suggesting that dupA and ERK1 are part of a response to bacteria. Indeed, over 500 of the genes misregulated in the dupA(-) mutant were regulated in response to L. pneumophila infection, including some thought to have immune-like functions. MAP kinase phosphatases are known to be highly upregulated in macrophages challenged with L. pneumophila. Thus, DupA may regulate a MAP kinase response to bacteria that is conserved from amoebae to mammals
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