Results 1 - 10 of 1879
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[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] The theory of the coherent creation of pairs by photon in the alignment crystal under conditions when the created electron and positron moving in the axial channeling regime is developed. In this case combined effect takes place which consist in a broadening of the width and changing of the shape and to appearance of the fine structure of the coherent peaks.
[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
[en] The author presents an atlas of spectral fine structures of solar radio bursts of types IV and II around 1 m wavelength, as obtained with a multichannel spectrograph at Dwingeloo. The structures form largely a collection of observations of these events during late 1968 through 1974, thus covering almost entirely the declining branch of solar cycle 20. The spectrograph has an extra enhanced contrast output with properties quite different from those of the commonly used swept frequency spectrographs. The corresponding instrumental characteristics and effects are discussed. A classification of fine structures and an analysis of their statistical properties and of those of the pertinent radio events are also given. (Auth.)
[en] High resolution photographs obtained at the Pic du Midi Observatory show that there are three types of sunspot light bridges according to their morphological structures: the photospheric ones, the penumbral ones and the umbral ones. Consequently there are no specific structures in light bridges; it results that they should not be due to specific physical properties. Properties of the fine structure of a penumbral light bridge are described. (Auth.)
[en] We emphasize the role played by the transversal component of the Poynting vector in relating classical electromagnetic with quantum theory, by calculating the actual value of ℎ and α-1. These two constants turn out to be closely related to one another and in very good agreement with their experimental values; neither one though seems to be really a fundamental constant. (orig.)
[en] The use of high fields in NMR spectroscopy can result in extra fine structure in the spectrum as a consequence of alignment of the molecules by the magnetic field of the spectrometer. The new information available provides a powerful tool in the analysis of structure and interactions of molecules in liquid solution. (author). 17 refs.; 2 figs
[en] The nature and limitations of the photoelectron spectroscopy (PES) of Pu is discussed, particularly the absence of detailed fine structure. A novel experiment, Fano Spectroscopy, is suggested as a means to obtain additional fine structure, with which to bench-mark and differentiate theoretical models