Results 1 - 10 of 2004
Results 1 - 10 of 2004. Search took: 0.026 seconds
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[en] By using first-principles calculations, we calculate the vibronic fine structure in photoelectron spectra of C20- clusters. Based on our results, we assign one of the recently observed spectra [H. Prinzbach et al. Nature (London) 407, 60 (2000)] to the fullerene structure and, therefore, confirm the experimental claim that the smallest fullerene is really synthesized
[en] In analogy to f(R) theory, recently a new modified gravity theory, namely the so-called f(T) theory, has been proposed to drive the current accelerated expansion without invoking dark energy. In the present work, by extending Bisabr's idea, we try to constrain f(T) theories with the varying fine structure 'constant', α≡e2/hc. We find that the constraints on f(T) theories from the observational Δα/α data are very severe. In fact, they make f(T) theories almost indistinguishable from ΛCDM model.
[en] One scenario proposed to explain the million degree solar corona is a finely stranded corona where each strand is heated by a rapid pulse. However, such fine structure has neither been resolved through direct imaging observations nor conclusively shown through indirect observations of extended superhot plasma. Recently, it has been shown that the observed difference in the appearance of cool and warm coronal loops (∼1 MK and ∼2-3 MK, respectively)-warm loops appearing 'fuzzier' than cool loops-can be explained by models of loops composed of subarcsecond strands, which are impulsively heated up to ∼10 MK. That work predicts that images of hot coronal loops (∼> 6 MK) should again show fine structure. Here we show that the predicted effect is indeed widely observed in an active region with the Solar Dynamics Observatory, thus supporting a scenario where impulsive heating of fine loop strands plays an important role in powering the active corona.
[en] Considered is the statistical ground of the certainty of cosmophysical effects on the fine structure of distributions governing the results of measurements in various physical processes. We show that the previously discussed effects of synchronous variations of histogram shapes in independent processes, and the periodical occurrence of histograms of a particular shape, do not depend on the form of the integral distribution. The adequacy of visual (expert) estimation when comparing the shapes of histograms as an alternative to the standard statistical methods is justified. (letters to the editors)
[en] It would appear that one of Wyler's calculations of the fine-structure constant is based on an incorrect value of the coefficient of the Poisson kernel for Cartan's third (fourth) classical domain, and hence that the value of the fine-structure constant may not be derivable from Wyler's assumptions. (author)
[en] It is suggested a possible connection between two empirical astrophysical laws concerning the angular momentum of celestial bodies.It is shown that both relations seem to indicate that the fine-structure constant α is the typical dimensionless parameter not only of atomic physics, but also of gravitational physics
[en] An attempt is made for a new type of analysis of the time-variability of the fine-structure constant trying to fit the most recent result from the laboratory measurements, the Oklo constraint and the data from the QSO absorption lines all in consistency with the accelerating universe