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101.
Prof. Dr. Wolfgang M. Schmidt 《Monatshefte für Mathematik》1976,82(3):237-245
The first question is about a possible variation on Dirichlet's approximation theorem for linear forms x+y+z, wherex,y are restricted topositive integers. The second question, which turns out to be related to the first, is about approximation to elements in a power series fieldk((t
–1)) by solutions of first order linear differential equationsx+y+z=0, wherex,y,z are polynomials int.
Dedicated to Prof. Dr. E. Hlawka on the occasion of his 60th birthday 相似文献
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A solid state metathesis (SSM) reaction was investigated with respect to the formation of rare‐earth carbodiimides, the role of the co‐produced salt (LiCl), and the eutectic flux medium (LiCl/KCl). A SSM reaction is characterized by an exothermic reaction in which a salt (often LiCl) is coproduced. When the salt melts, it can serve as a useful medium for the crystallization of a desired product. An improved crystal growth can be observed by using an eutectic flux. However, the composition of an eutectic LiCl/KCl flux is altered when LiCl is produced during the reaction. The thermal effects concerning the endothermic melting of the flux and the exothermic ingnition of the SSM reaction may compensate each other, which is not necessarily a drawback for the reaction to proceed. 相似文献
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Maurits Kuiper Manfred Speldrich Helmut Schilder Prof. Dr. Heiko Lueken 《无机化学与普通化学杂志》2012,638(10):1432-1436
Abstract. The magnetic behavior of the mononuclear nd1 systems MCp2Cl2 (M = V4+[3d1], Nb4+[4d1], Ta4+[5d1], space group P21/c, pseudosymmetry of the molecules C2v) deviates from pure single ion spin magnetism on account of ligand field effect (Hlf), spin‐orbit coupling (Hso), and intermolecular spin‐spin exchange interactions (Hex). For both VCp2Cl2 and NbCp2Cl2 excellent adaptations to the measured susceptibility data were obtained (2 K ≤ T ≤ 300 K) on the basis of spectroscopic data (lf, so) and cooperative metal–metal interactions (ex) of antiferromagnetic nature [molecular field model (mf)]. For TaCp2Cl2 experimental term structure data are not available. Therefore, Jørgensen's spectroscopical series (g‐factor of the central ion) was applied to extrapolate the data set for TaCp2Cl2. Hlf, Hso, and Hex (antiferromagnetic) increase in the order 3d1 → 4d1 → 5d1 leading, with rising atomic number of the metals, to a distinct enhancement of the magnetic anisotropy. At 4 K the μeff components μeff,y (oriented perpendicular to the cg–M–cg plane; “cg” = center of gravity of the Cp ring), μeff,z (oriented along the twofold pseudoaxis), and μeff,x are 1.73, 1.69, 1.68 (V), 1.73, 1.62, 1.59 (Nb), and 1.71, 1.59, 1.49 (Ta). While μeff,y is independent of T, both μeff,z and μeff,x decrease with decreasing T. 相似文献
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