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Maria Stella Mongioví Silvana Romeo 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1996,47(1):144-161
A dissipative model of helium II was built up in previous works, using a 13-field extended thermodynamic theory formulated by Liu and Müller. In this work a generalization of such model is presented, where an extended thermodynamics with 14 fields due to Kremer is used. It is shown that the fourteenth field is able to account for the experimental data concerning the second sound attenuation. Further, the proposed theory is able to explain the Osborne experiment. Finally, a comparison with the two-fluid model is performed, emphasizing the different ways in which the dissipative phenomena are explained by the two theories. 相似文献
64.
This research was done while the last two authors were visitors at the University of Mainz. They are grateful to the Department of Mathematics for its excellent hospitality. 相似文献
65.
Claude F. Bernasconi 《Tetrahedron》1985,41(16):3219-3234
The Principle of Imperfect Synchronization (PIS) states that a product stabilizing factor will lower the intrinsic rate of a reaction if it develops late, but increase the intrinsic rate if the factor develops early. It is shown in this paper that much of the structure-reactivity behavior of proton transfers involving carbon acids can be understood in the context of this principle. The factors discussed include the effect of resonance near the reaction site as well as in remote substituents, the polar effect of mote substituents, and the effects of solvation of reactants and products A sample matheatical formalism is developed to describe the contribution of each factor to the intrinsic rate constant. The possible reasons why there is a lack of synchronization between the various events which occur during the reaction are also discussed 相似文献
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Abstract— Photolysis of N,N-dimethylthymine (DMT) and urocanic acid (UA) gives rise to two isolable cyclobutane adducts. N,N-dimethylthymine also photosensitizes UA E / Z isomerization. Neither phenomenon is affected by a triplet quencher, and 1 DMT* is proposed as the likely reactive species. If so, prior complexation of DMT and UA would be necessary in order for their interaction to be competitive with DMT radiationless decay. These observations are potentially related to the effect of UA on viral DNA described in the following paper. 相似文献
68.
Highly selective enzymatic reductions of aldehydes to the corresponding alcohols was performed using an E. coli JM109 whole cell biocatalyst. A selective enzymatic method for the reduction of aldehydes could provide an eco-compatible alternative to chemical methods. The simplicity, fairly wide scope and the very high observed chemoselectivity of this approach are its most unique features. 相似文献
69.
Gervásio A. Degrazia Otávio C. Acevedo Silvana Maldaner Umberto Rizza 《Physica A》2010,389(24):5808-5813
The classical statistical diffusion theory and the binomial autocorrelation function are used to obtain a new formulation for the turbulence dissipation rate ε. The approach employs the Maclaurin series expansion of a logarithm function contained in the dispersion parameter formulation. The numerical coefficient of this new relation for ε is 100% larger than the numerical coefficient of the classical relation derived from the exponential autocorrelation function. A similar approach shows that the dispersion parameter obtained from the even exponential autocorrelation function does not result in a relation for ε and, therefore, is not suitable for application in dispersion models. In addition, a statistical comparison to experimental ground-level concentration data demonstrates that this newly derived relation for ε as well as other formulations for the turbulence dissipation rate are suitable for application in Lagrangian stochastic dispersion models. Therefore, the analysis shows that there is an uncertainty regarding the turbulence dissipation rate function form and the autocorrelation function form. 相似文献
70.
In this work we study properties of random graphs that are drawn uniformly at random from the class consisting of biconnected
outerplanar graphs, or equivalently dissections of large convex polygons. We obtain very sharp concentration results for the
number of vertices of any given degree, and for the number of induced copies of a given fixed graph. Our method gives similar
results for random graphs from the class of triangulations of convex polygons. 相似文献