1,721,154 research outputs found
Anelastic processes in calix[n]arene-type organic molecules
No full textWe measured the anelastic spectrum of two organic molecules, calix[4]arene and p-tert-but-calix[4]arene. In both samples, a peak observed around 45-60 K for a measurement frequency of about 1 kHz was ascribed to the hopping of H atoms of the O-H groups, due to the close similarity of the physical parameters of these peaks with those obtained by a NMR relaxometry study. The present results reveal that anelastic spectroscopy is a good tool for studying atomic motion inside molecules at a mesoscopic level. (C) 2003 Elsevier B.V. All rights reserved
Nonlinear interaction between galloping modes
No full textA coupled, nonlinear, flexural two degree-of-freedom model, describing a perfectly flexible elastic suspended cable subject to galloping, is analyzed. By using a perturbative technique, two different critical conditions, corresponding to simple or double Hopf bifurcations, are found for different values of the aerodynamic coefficients. The nonlinear post-critical behavior of single taut strings in 1:1 primary internal resonance is studied through the multiple scale perturbation method. In the double Hopf bifurcation case the important role of the detuning between the critical eigenvalues on the post-critical behavior is highlighted. It is found that quasi-periodic motions, which are likely to occur in the linear field when the two critical frequencies are uncommensurable, are unstable in the nonlinear range. Therefore the postcritical behavior of the string is always characterized by stable periodic motions for any detuning values
Cluster spin glass phase and charge stripe fluctuations in the high TC superconductor La2-xSrxCuO4
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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