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211.
Hugo Volger 《Mathematische Zeitschrift》1968,106(4):312-320
Ohne Zusammenfassung 相似文献
212.
The optimum conditions for the photometric determination of tantalum with pyrogallol in sulphuric acid solution at 405 nm have been elaborated. The method has been checked statistically. 相似文献
213.
Arnošt Bergstein 《Czechoslovak Journal of Physics》1956,6(2):164-168
Zusammenfassung Es wurden einige dielektrische Eigenschaften polykristalliner gesinterter Bleioxydproben gemessen. Aus den Ergebnissen wird auf zwei Polarisationsvorgänge geschlossen, die bei niedrigen Frequenzen und Temperaturen zwischen 20–60 °C gleichzeitig die Werte der Dielektrizitätskonstante beeinflussen. Einer von ihnen ist mit dem Auftreten orientierter Bereíche verbunden, die spontane Polarisierung aufweisen, deren Sinn durch ein äusseres elektrisches Feld um 180° gedreht werden kann. 相似文献
214.
Lauri J. Missio Hugo S. Braibante Mara E. F. Braibante 《Journal of heterocyclic chemistry》1996,33(4):1243-1245
The reactivity of the enamino compounds 4-amino-3-phenylamino(thio)carbonyl-3-penten-2-one 1 and 2 and ethyl 3-amino-2-phenylamino(thio)carbonyl-2-butyrate 7 and 8 was studied using the reaction with hydrazine hydrate and hydrazine hydrochloride to evaluate the 1,3 electrophilic center of the compounds by the formation of the pyrazole rings. The pyrazoles 3, 4, 5, 9, 11 and 13 were obtained depending on the reaction conditions employed. 相似文献
215.
Hugo M. Ortner Gerhard Schlemmer Bernhard Welz W. Wegscheider 《Spectrochimica Acta Part B: Atomic Spectroscopy》1985,40(7):959-977
Morphological studies on graphite tube surfaces by scanning electron microscopy are presented for unused and corroded tubes from various endurance experiments in electrothermal AAS.Tubes always break in their center as this is the hottest part; tube thinning occurs predominantly at the outside. The inner surface of tubes coated with pyrographite is usually only slightly corroded, unless highly aggressive reagents are applied. Deposition of carbon in thin layers as well as in nodules is observed in the hot central zone. 相似文献
216.
The ground state of a double-exchange model for orbitally degenerate e(g) electrons with Jahn-Teller lattice coupling and weak disorder is found to be spatially inhomogeneous near half filling. Using a real-space Monte Carlo method we show that doping the half-filled orbitally ordered insulator leads to the appearance of hole-rich disordered regions in an orbitally ordered environment. The doping driven orbital order to disorder transition is accompanied by the emergence of metallic behavior. We present results on transport and optical properties along with spatial patterns for lattice distortions and charge densities, providing a basis for an overall understanding of the low-doping phase diagram of La1 - xCaxMnO3. 相似文献
217.
Benjamin Braun Hugo Corrales Scott Corry Luis David García Puente Darren Glass Nathan Kaplan Jeremy L. Martin Gregg Musiker Carlos E. Valencia 《Discrete Mathematics》2018,341(10):2949-2963
Let be a finite, connected graph. An arithmetical structure on is a pair of positive integer vectors such that , where is the adjacency matrix of . We investigate the combinatorics of arithmetical structures on path and cycle graphs, as well as the associated critical groups (the torsion part of the cokernels of the matrices ). For paths, we prove that arithmetical structures are enumerated by the Catalan numbers, and we obtain refined enumeration results related to ballot sequences. For cycles, we prove that arithmetical structures are enumerated by the binomial coefficients , and we obtain refined enumeration results related to multisets. In addition, we determine the critical groups for all arithmetical structures on paths and cycles. 相似文献
218.
We deal with anomalous diffusions induced by continuous time random walks - CTRW in ?n. A particle moves in ?n in such a way that the probability density function u(·, t) of finding it in region Ω of ?n is given by ∫Ωu(x, t)dx. The dynamics of the diffusion is provided by a space time probability density J(x, t) compactly supported in {t ≥ 0}. For t large enough, u satisfies the equation , where δ is the Dirac delta in space-time. We give a sense to a Cauchy type problem for a given initial density distribution f. We use Banach fixed point method to solve it and prove that under parabolic rescaling of J, the equation tends weakly to the heat equation and that for particular kernels J, the solutions tend to the corresponding temperatures when the scaling parameter approaches 0.
相似文献
$$u\left( {x,t} \right) = \left[ {\left( {J - \delta } \right)*u} \right]\left( {x,t} \right)$$
219.
220.
Arno Fehm 《Journal of Algebra》2010,323(6):1738-1744