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Xiaopeng Zhao David G. Schaeffer Carolyn M. Berger Daniel J. Gauthier 《Nonlinear dynamics》2007,48(4):381-389
Various authors have shown that, near the onset of a period-doubling bifurcation, small perturbations in the control parameter
may result in much larger disturbances in the response of the dynamical system. Such amplification of small signals can be
measured by a gain defined as the magnitude of the disturbance in the response divided by the perturbation amplitude. In this
paper, the perturbed response is studied using normal forms based on the most general assumptions of iterated maps. Such an
analysis provides a theoretical footing for previous experimental and numerical observations, such as the failure of linear
analysis and the saturation of the gain. Qualitative as well as quantitative features of the gain are exhibited using selected
models of cardiac dynamics. 相似文献
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AndrewF. Kiely MarkS. Meier BrianO. Patrick JohnP. Selegue Carolyn PrattBrock 《Helvetica chimica acta》2003,86(4):1140-1151
The crystal structure of 7,8‐(dichloromethano)homo[70]fullerene shows that addition of the dichlorocarbene (:CCl2) to C70 gives a surprisingly normal methano‐bridged [9]annulene. The structural changes caused by the addition are highly localized; the C(7)? C(8) distance lengthens by 0.705(2) Å but no other distance changes by more than 0.022(3) Å. Bond angles within the [9]annulene increase by as much as 7.8(1)°, but changes outside the C9 ring are much smaller. The nearly ellipsoidal molecules form hexagonally close‐packed layers that interact in pairs through short Cl???C, and possibly short Cl???Cl and C???C, interactions. 相似文献
65.
Carolyn C. Woodroofe 《Tetrahedron》2005,61(12):3097-3105
Xanthene-based fluorophores such as fluorescein and rhodamine are typically prepared by acid-catalyzed condensation of the appropriate resorcinol or 3-aminophenol with phthalic anhydride. Condensation of substituted phthalic anhydride species results in functionalized fluorophores that are formed as mixed isomers. Crystallization approaches to isomer separation have been reported elsewhere for symmetric fluorescein carboxylates. We describe crystallization-based separation of protected fluorescein sulfonates and coupling conditions to form sulfonamides, precursors for carboxylate-substituted rhodamines, and precursors for asymmetrically substituted fluoresceins and rhodafluors. 相似文献
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