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101.
Nonlinear Dynamics - In this work, the combination of the 0–1 test for chaos and approximate entropy is applied to a newly established mechanical model instead of the Lyapunov exponent... 相似文献
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The choice of lateral and terminal substitution can have a major influence on the structure of a liquid crystalline supermolecule, which in turn can induce radically different phase behaviour. In this study we use molecular dynamics simulations to investigate the shape of a liquid crystal dendrimer within a liquid crystalline solvent. A coarse-grained (CG) simulation model is employed to represent a third generation dendrimer in which 32 mesogenic groups are bonded to chains at the end of each branch of the dendrimer. In this CG-model the liquid crystal groups can be appended either terminally or laterally. This bonding option is used to generate the structure of four separate systems: (a) a dendrimer with 32 terminal mesogens, (b) a dendrimer with 32 laterally appended mesogens, (c) and (d) dendrimers with 16 lateral and 16 terminal groups represented with laterally bonded sites on one side of the molecule, model (c) or next to terminally bonded sites, model (d). The simulations show that the dendrimer is able to change shape in response to molecular environment and that the molecular shape adopted depends critically on the nature of the lateral/terminal susbstitution. 相似文献
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Jaroslav Fabian 《Czechoslovak Journal of Physics》1993,43(11):1137-1142
In the paper it is shown that it is possible to apply the BCS theory to the Hubbard model with positiveU for a half-filled band. A calculation of the ground-state energy of the model is presented. 相似文献
107.
Abstract— Corrected emission spectra and fluorescence lifetimes of polycytidylic acid in ethylene glycol: water glass at low temperatures are reported. Luminescence properties observed exhibit a strong dependence on pH and temperature. At neutral pH a vibronic structure of a blue part of the fluorescence spectrum is revealed when temperature is changed from 77 to 10 K, confirming that a monomer component of fluorescence is present. There is also a strong difference in decay of a red-shifted excimer fluorescence at 10 K at pH 7 and pH 3.9, reflecting a different protonation of cytosine residues and different conformations of polynucleotides in such conditions. 相似文献
108.
In this paper we exhibit a triangular map F of the square with the following properties: (i) F is of type 2∞ but has positive topological entropy; we recall that similar example was given by Kolyada in 1992, but our argument is much simpler. (ii) F is distributionally chaotic in the wider sense, but not distributionally chaotic in the sense introduced by Schweizer and Smítal [Trans. Amer. Math. Soc. 344 (1994) 737]. In other words, there are lower and upper distribution functions Φxy and Φxy* generated by F such that Φxy*≡1 and Φxy(0+)<1, and no distribution functions Φuv, and Φuv* such that Φuv*≡1 and Φuv(t)=0 whenever 0<t<ε, for some ε>0. We also show that the two notions of distributional chaos used in the paper, for continuous maps of a compact metric space, are invariants of topological conjugacy. 相似文献
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The effect of carbide particles of M4C3 and M23C6 on the creep properties of low-alloy and modified chromium steels is investigated.Presented at the 4th International Symposium on Plasticity of Metals and Alloys, Srní, Czechoslovakia, September 7–11, 1987. 相似文献
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