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961.
962.
Extremal Rational Functions on Symmetric Discrete Sets and Superlinear Convergence of the ADI Method
There is a very fruitful interaction between numerical linear algebra and logarithmic potential theory. For instance, we may
describe weak asympotics for a polynomial extremal problem occurring in the convergence analysis of conjugate gradients (CG)
or of Ritz values; here the link with a constrained minimal energy problem allows to quantify the effect of superlinear convergence. 相似文献
963.
964.
Tris(9′,10′‐dimethyl[9,10]ethanoanthracene[11′,12′: 1,9;11″,12″: 16,17;11′′′,12′′′: 30,31])[5,6]fullerene C60, the orthogonal (e,e,e)‐tris‐adduct of C60 and 9,10‐dimethylanthracene, was obtained from [4+2]‐cycloaddition (Diels–Alder reaction) at room temperature. The thermally unstable orange red (e,e,e)‐tris‐adduct was purified by chromatography and was isolated in the form of red monoclinic crystals. Its C3‐symmetric addition pattern was established spectroscopically. Its structure could be further investigated by single crystal X‐ray diffraction. The (e,e,e)‐tris‐adduct of C60 and 9,10‐dimethylanthracene has earlier been suggested as intermediate and reversibly formed critical component in ‘template directed’ addition reactions of C60. This previously elusive compound has now been isolated and structurally characterized. 相似文献
965.
Bernhard Köck 《Mathematische Annalen》1999,314(4):667-702
966.
968.
Navabeeh Nami Chamazi Majid M. Heravi Bernhard Neumüller Prof. Dr. 《无机化学与普通化学杂志》2007,633(8):1239-1242
Organoalkoxochlorogallanes Me2GaCl was treated with nBuOH and iBuOH in a molar ration of 1:2, respectively. However, only one equivalent of the alcohol reacted with MeGaCl2 to give [MeGa(Cl)OnBu]3 ( 1 ) or [MeGa(Cl)OiBu]3 ( 2 ). 1 and 2 were characterized by NMR and IR techniques as well as by X‐ray structure determinations. According to that 1 and 2 form trimers in solution and the solid state. In solution both isomers Cs and C3v were observed while the trimers exist only as Cs isomers in the solid state which exhibit strongly distorted boat conformations with a disorder of the Cl/Me position at one of the gallium atoms. 相似文献
969.
Daniel Lumpi Christian Hametner Bernhard Zachhuber Johannes Fröhlich 《Tetrahedron letters》2009,50(47):6469-6471
A convenient approach for the synthesis of monodisperse oligo(ethylene glycols) up to 12 units is described. A novel cleavage protocol replacing laborious hydrogenolysis is introduced to achieve a fast, inexpensive and widely applicable procedure. In addition to the synthetic part, Fourier transform infrared (FTIR) spectroscopy using a fibre optic attenuated total reflection (ATR) sensor was applied to monitor the formation of sensitive key intermediates, resulting in optimized reaction times. By applying this in-line technique, the possibility of real-time analysis under inert conditions was impressively demonstrated. 相似文献
970.