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[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] It is conventional to imagine that the various parameters which characterize our physical theories, such as the fine structure constant or Newton's gravitational constant, are truly 'constant', in the sense that they do not change from place to place or time to time. Recent developments in both theory and observation have led us to re-examine this assumption, and to take seriously the possibility that our supposed constants are actually gradually changing. I will discuss why we might expect these parameters to vary, and what observation and experiment have to say about the issue.
[en] High-resolution photoionization experiments were carried out with beams of C III, N IV, and O V containing roughly equal amounts of ground-state and metastable ions. The energy scales of the experiments are calibrated with uncertainties of 1 to 10 meV depending on photon energy. These data favorably compare with state-of-the-art R-matrix calculations carried out on an energy grid with a spacing of 13.6 μeV
[en] A simple relation between the time-dependent fine-structure and gravitational constants of alpha/alpha2 approx G/G is derived from the hypothesis that both of these fundamental constants are related to the more fundamental length scale of nature as in he unified pregauge and pregeometric theory of all fundamental forces. From the latest observation of alpha/alpha = (-1.91 ± 0.54) centre dot 10-15yr-1 by Webb et al., it leads to the prediction of G/G = (-0.154 ± 0.044) centre dot 10-12yr-1, which is not only consistent with the most precise limit of G/G = (-0.6 ± 2.0) centre dot 10-12yr-1 by Thorsett but also feasible for future experimental tests
[en] Full text: Fine structure in VLEED reflectivity data near beam emergences arises from scattering at the surface potential barrier. For metals, including Cu(001), many studies have attempted to analyse this data to obtain, particularly, the origin zo from the image potential which exists at metal surfaces, as well as the saturation from image barrier form closer to the surface. For Cu(001), analyses from 1979 to 1999 have stated determinations of zo from -1.3 ± 0.3 a.u. to -3.2 ± 0.2 a.u. from the centre of the top layer of atoms with some data fits also for zo as large as 3.7 a.u. This paper explores why such differing sets of results have been obtained and how one can successfully extract definitive information of the surface barrier structure from high resolution VLEED data