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91.
Becker SM Scheuermann M Sepelák V Eichhöfer A Chen D Mönig R Ulrich AS Hahn H Indris S 《Physical chemistry chemical physics : PCCP》2011,13(43):19624-19631
We studied the electrochemical insertion of Li in mechanochemically prepared Zn(2)SnO(4). The mechanism of the electrochemical reaction was investigated by using X-ray diffraction, nuclear magnetic resonance spectroscopy, and M?ssbauer spectroscopy. Changes in the morphology of the Zn(2)SnO(4) particles were studied by in situ scanning electron microscopy. The results were compared with mixtures of SnO(2) + ZnO and with Zn(2)SnO(4) prepared by conventional solid-state synthesis and showed that the mechanochemically prepared Zn(2)SnO(4) exhibits the best cyclic stability of these samples. 相似文献
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We give a positive answer for the special case of the Generalized Baues Problem which asks whether the complex of triangulations
of a point set A in general position in the plane has the homotopy type of a sphere. In the process, we are led to define the visibility complex for a simplicial complex P whose vertices lie in A , and prove that this visibility complex has the same homotopy type as P . The main technique is a variant of deletion-contraction from matroid theory, along with a new method for proving homotopy equivalence of posets which we call the nerve-flag paradigm.
Received January 23, 1997, and in revised form June 20, 1997. 相似文献
95.
Jürgen Ensling Philipp Gütlich Reiner Klinger Werner Meisel Harald Jachow Ekkehard Schwab 《Hyperfine Interactions》1998,111(1-4):143-150
CrO2 doped with 1--2 wt% Fe3+ on Cr4+ positions is one of the most important materials for magnetic recording in audio, data and video tapes. 57Fe Mössbauer spectroscopy was applied to determine the level of iron doping in newly developed high coercivity CrO2 particles. It was found that, compared with the conventional preparation process, the new particles contain increased amounts of Fe3+ ions in the CrO2 crystal lattice giving rise to higher magnetocrystalline anisotropy. This is reflected in coercivities of up to over 900 Oe. All samples contain as a secondary iron-containing phase α-(Cr1-xFex)2O3, the amount of which is higher in samples of the conventional preparation process than in those of the new BASF process. Details about the mechanism of the development of doped CrO2 particles in both types of processes were obtained by means of Mössbauer, XRD and wet chemical investigations making possible an optimization of the new BASF process. 相似文献
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Knut Reiner Rainer Richter Siegfried Hauptmann Jan Becher Lothar Hennig 《Tetrahedron》1995,51(48):13291-13300
A series of pyrazole type tetrakis compounds has been synthesized by reaction of aromatic or heterocyclic dialdehydes and pyrazolone derivatives. Structure and tautomerism of the products were investigated by spectroscopic methods and X-ray analysis. Several tetrakis compounds form inclusion complexes with solvents like alcohols, ethers, and ketones in a definite ratio via hydrogen bonds. 相似文献