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81.
K. Torkar G. W. Herzog W. Schintlmeister Dieter Fischer 《Monatshefte für Chemie / Chemical Monthly》1967,98(2):245-253
It is shown that in the case of thermal decomposition of sodium azide the overall kinetics can be predicted by defined particle size of the decomposed sodium azide crystals. This is always the case if the rate constant is a function of the particle size. Hence this special example can be generalized for similar decomposition reactions. It is necessary that the particles decompose independently which could be proved experimentally with sodium azide. If for this reason we state for true that the pressure/time-function of each particle size add together it is possible to set up a formula for the pressure/time-function of any particle size distribution. With the pressure/time function holding for sodium azide of uniform particle size, the total function for a Gauß distribution can be calculated exactly. Moreover, the trivial case of one single particle size and the case of two different particle sizes are discussed. Furthermore an approximation method for any arbitrary pressure/time-functions and distribution by means of “Schwerpunktdeutung” are discussed which can be carried out graphically as well as numerically. The numerical approximation is illustrated by an example. Pressure/time-functions then loose their characteristic form because of their dependence on the particle size distributions under consideration. In this case, reaction mechanism cannot be derived from pressure/time functions. 相似文献
82.
83.
Dieter H. Mayer 《Journal of statistical physics》1985,38(3-4):785-803
We derive universal scaling properties for k–1 actions on the circle whose generators have rotation numbers algebraic of degreek. As fork=2 these properties can be explained for arbitraryk in terms of a renormalization group transformation. It has at least one trivial fixed point corresponding to an action whose generators are pure rotations. The spectrum of the linearized transformation in this fixed point is analyzed completely. The fixed point is hyperbolic with a (k–1)-dimensional unstable manifold. In the casek=2 the known results are therefore recovered. 相似文献
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88.
Roland Boese Dieter Bläser Michael Nussbaumer Tadeusz Marek Krygowski 《Structural chemistry》1992,3(5):363-368
The crystal and molecular structure of nitrobenzene was determined at 103 K by X-ray diffraction, yieldingR=0.034 and a highly precise geometry of the molecule (esds of bond lengths 0.001 Å and bond angles 0.1°). The bond angles in the ring agree very well with additive scheme based on angular substituent parameters. X-X electron density maps support the view that the C-N bond does not exhibit-character, and, hence, the nitro group interacts with the ring mostly by inductive effects. 相似文献
89.
The carrier mediated transport of cations using model compounds of the verdinoid and rubinoid bile pigment structural type as ionophores is studied. Verdinoid bile pigments turn out to be very effective carriers for cations exhibiting a pronounced selectivity for certain transition metal ions like Cr+-+, Fe++, Cu++ and Zn++. The scope of this behaviour of verdinoid bile pigments is compared to [18]-crown-6 and meso-tetraphenylporphin and is discussed with regard to structural, biological, analytical and technical implications. 相似文献
90.
(CF3)4Te is formed from the reaction of (CF3)2TeCl2 with (CF3)2Cd·glyme in CH3CN at ?10°C via the intermediate (CF3)3TeCl as a yellow liquid and identified by n.m.r. and mass spectra. 相似文献