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221.
Nathalie Revol 《PAMM》2007,7(1):1023003-1023004
The implementation of Taylor models arithmetic may use floating-point arithmetic to benefit from the speed of the floatingpoint implementation. The issue is then to take into account the roundoff errors. Here, we assume that the floating-point arithmetic is compliant with the IEEE-754 standard. We show how to get tight bounds of the roundoff errors, and more generally how to get high accuracy for the coefficients as well as for the bounds on the roundoff errors 相似文献
222.
Erwann Jeanneau Nathalie Audebrand Daniel Louër 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1012-1013
Crystals of anhydrous cadmium oxalate, β‐[Cd(C2O4)], have been synthesized hydrothermally and the crystal structure solved using single‐crystal X‐ray diffraction data. The Cd and oxalate ions lie about independent inversion centres. The structure consists of a three‐dimensional framework built from sheets of cadmium octahedra linked together by oxalate groups. 相似文献
223.
Alexander Mutschke Annika Schulz Marko Bertmer Clemens Ritter Antti J. Karttunen Gregor Kieslich Nathalie Kunkel 《Chemical science》2022,13(26):7773
The four compounds A3MO4H (A = Rb, Cs; M = Mo, W) are introduced as the first members of the new material class of the transition oxometalate hydrides. The compounds are accessible via a thermal synthesis route with carefully controlled conditions. Their crystal structures were solved by neutron diffraction of the deuterated analogues. Rb3MoO4D, Cs3MoO4D and Cs3WO4D crystallize in the antiperovskite-like K3SO4F-structure type, while Rb3WO4D adopts a different orthorhombic structure. 2H MAS NMR, Raman spectroscopy and elemental analysis prove the abundance of hydride ions next to oxometalate ions and experimental findings are supported by quantum chemical calculations. The tetragonal phases are direct and wide band gap semiconductors arising from hydride states, whereas Rb3WO4H shows a unique, peculiar valence band structure dominated by hydride states.The synthesis, structures and electronic properties of the first four heteroanionic compounds containing both hydride and transition oxometalate ions are reported. 相似文献
224.
Manal Diab Ana Mateo Joumada El Cheikh Zeinab El Hajj Mohamed Haouas Alireza Ranjbari Vincent Gurineau David Touboul Nathalie Leclerc Emmanuel Cadot Daoud Naoufal Carles Bo Sbastien Floquet 《Molecules (Basel, Switzerland)》2022,27(22)
Herein we report the synthesis of a new class of compounds associating Keggin and Dawson-type Polyoxometalates (POMs) with a derivative of the anionic decahydro-closo-decaborate cluster [B10H10]2− through aminopropylsilyl ligand (APTES) acting as both a linker and a spacer between the two negatively charged species. Three new adducts were isolated and fully characterized by various NMR techniques and MALDI-TOF mass spectrometry, notably revealing the isolation of an unprecedented monofunctionalized SiW10 derivative stabilized through intramolecular H-H dihydrogen contacts. DFT as well as electrochemical studies allowed studying the electronic effect of grafting the decaborate cluster on the POM moiety and its consequences on the hydrogen evolution reaction (HER) properties. 相似文献
225.
Phosphatidylinositol-specific phospholipase C (PI-PLC) enzymes are a virulence factor in many Gram-positive organisms. The specific activity of the Bacillus thuringiensis PI-PLC is significantly increased by adding phosphatidylcholine (PC) to vesicles composed of the substrate phosphatidylinositol, in part because the inclusion of PC reduces the apparent Kd for the vesicle binding by as much as 1000-fold when comparing PC-rich vesicles to PI vesicles. This review summarizes (i) the experimental work that localized a site on BtPI-PLC where PC is bound as a PC choline cation—Tyr-π complex and (ii) the computational work (including all-atom molecular dynamics simulations) that refined the original complex and found a second persistent PC cation—Tyr-π complex. Both complexes are critical for vesicle binding. These results have led to a model for PC functioning as an allosteric effector of the enzyme by altering the protein dynamics and stabilizing an ‘open’ active site conformation. 相似文献
226.
W. Palmaer E. Heyn O. Bauer H. E. Searle F. L. La Que W. R. van Wijk H. J. Lodeesen Nathalie Goldowski H. Fournier H. Thyssen J. Bourdouxhe E. Naumann U. R. Evans und W. Blum 《Fresenius' Journal of Analytical Chemistry》1939,116(5-6):216-221
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227.
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229.
Emmanuel Bongiovanni Alexandre Ern Nathalie Glinsky-Olivier 《Comptes Rendus Mathematique》2003,336(3):283-288
We consider the compressible Navier–Stokes equations for gas flows endowed with general pressure and temperature laws as long as they are compatible with the existence of an entropy and Gibbs relations. We extend the relaxation method introduced for the Euler equations by Coquel and Perthame. Keeping the same “sub-characteristic” conditions for the hyperbolic fluxes and using a consistent splitting of the diffusive fluxes based on a global temperature, we prove the stability of the relaxation system via the sign of the production of a suitable entropy. A first order asymptotic analysis around equilibrium states confirms the stability result. Finally, we present a numerical implementation of the method. To cite this article: E. Bongiovanni et al., C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
230.
Nathalie Hild Salah Khodja Chantal Andraud Isabelle Ledoux Joseph Zyss Andr Collet 《Optics Communications》1998,150(1-6):223-229
Two chiral organic nonlinear optical materials, (3S,4S)-(−)-6-cyano-2,2-dimethyl-3,4-epoxychroman (1) and (3R,4R)-(+)-6-nitro-2,2-dimethyl-3,4-epoxychroman (2), have been grown into single crystals of cm3-size. Although both compounds crystallise in the orthorhombic P212121 space group, they are not isomorphous and their crystal packings are quite different. Angle tuned type II phase-matched second harmonic generation between 0.8 and 1.064 μm has been evidenced, with effective nonlinear coefficients deff of 1 and 5 pm/V at 0.96 μm for 1 and 2, respectively. These values are in agreement with those estimated in the oriented gas model approximation using EFISH first order hyperpolarisability values (β0=2.6 and 4.0×10−30 esu for 1 and 2, respectively). 相似文献