The Coster-Kronig probability f23 for lead has been measured by a K-x-ray—L-x-ray coincidence technique. Analytic fitting of the Kα-x-ray triplet using nonlinear least-squares methodology was employed to determine t...
The Coster-Kronig probability f23 for lead has been measured by a K-x-ray—L-x-ray coincidence technique. Analytic fitting of the Kα-x-ray triplet using nonlinear least-squares methodology was employed to determine the corrections necessitated by the overlap of the Kα2 and Kα1 peaks. The result, 0.112±0.002, is to be compared with the Dirac-Hartree-Slater prediction of 0.122 and a recently measured value of 0.130±0.002 obtained by a different approach to the overlap correction. The present result may provide an estimate of relaxation and many-body effects, which—if included—would lower the Dirac-Hartree-Slater single-particle-model prediction.
Taking into account the possibility of particle-antiparticle pair production, we have investigated the onset of Bose-Einstein condensation in an ideal relativistic Bose gas confined to restricted geometries. Through a...
Taking into account the possibility of particle-antiparticle pair production, we have investigated the onset of Bose-Einstein condensation in an ideal relativistic Bose gas confined to restricted geometries. Through an extensive use of the Poisson summation formula, we have carried out an explicit evaluation of the summations over states appearing in the problem, which enables us to make a rigorous analysis of the temperature dependence of the thermogeometric parameter y of the system in the case of a cubical enclosure under periodic boundary conditions. This, in turn, leads us to determine the growth of the condensate fraction ρ0ρ as a smooth function of temperature from T≳Tc down to T=0 K. Finite-size corrections to the standard bulk results are obtained in explicit terms and are shown to be in complete agreement with the Fisher-Barber scaling theory for such effects. In the end, special geometries, such as narrow channels and thin films, are also examined.
An electronic analog simulation of two coupled superconducting microbridges is shown to give similar results to the numerical solution. For strongly coupled microbridges some new phenomena are revealed. Strongly coupl...
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An electronic analog simulation of two coupled superconducting microbridges is shown to give similar results to the numerical solution. For strongly coupled microbridges some new phenomena are revealed. Strongly coupled thin‐film microbridges were prepared by a new technique and their current‐voltage characteristics confirm some of the predictions that are indicated by the analog simulation.
Superconducting microbridges with lenghts ranging from shorter than to longer than the coherence length have been fabricated. Those microbridges whose length is longer than the coherence length do show a dynamic enhan...
Superconducting microbridges with lenghts ranging from shorter than to longer than the coherence length have been fabricated. Those microbridges whose length is longer than the coherence length do show a dynamic enhanced critical current in accordance with the theory of Schmid, Schön, and Tinkham. Those microbridges whose length is shorter than the coherence length do not exhibit a dynamically enhanced critical current and a possible reason for its absence is that the order parameter is depressed in the banks adjacent to the microbridge.
A measurement system for the current–voltage characterization of solar cells has been developed. The instrument is based on an Intel 8088 microprocessor, which allows for enhanced data collection and storage, as well...
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A measurement system for the current–voltage characterization of solar cells has been developed. The instrument is based on an Intel 8088 microprocessor, which allows for enhanced data collection and storage, as well as automated measurement control. A high‐power analog supply makes measurements in the range of ?10 to +10 V and ?0.75 to 0.75 A possible, and provides the capability for sinking currents up to 1 A at +10‐V output. Measured data may be transferred to an IBM personal computer for immediate display, and for consequent analysis (to obtain the characteristic parameters). The system provides a rapid, effective I–V curve measurement and analysis method for many devices, and experimental solar cells in particular.
The pair correlation function. g ( r ), for low-density chlorine gas was measured using neutron diffraction. A simple model for the system was used to demonstrate that density effects in g ( r ) should be negligible a...
The pair correlation function. g ( r ), for low-density chlorine gas was measured using neutron diffraction. A simple model for the system was used to demonstrate that density effects in g ( r ) should be negligible at the level of accuracy of the experiment. As a result there is a simple relationship between g ( r ) and the intermolecular interaction potential. Comparisons were made to theoretical calculations of g ( r ) using a published site-site model potential and a site-site plus quadrupole model. It was found that the site-site model was better than the site-site plus quadrupole model in the region of molecular contact. However, the temperature dependence of neither model was satisfactory.
We reanalyse the published X-ray diffraction data on water with the object of deducing the isochoric temperature derivative of the structure factor of H 2 O at 4°C and 1 atm. These results are compared to the pub...
We reanalyse the published X-ray diffraction data on water with the object of deducing the isochoric temperature derivative of the structure factor of H 2 O at 4°C and 1 atm. These results are compared to the published molecular dynamics results for the MCY potential. Similar (published) neutron-diffraction results are discussed. The effect of “hydrogen-bond formation” on neutron and X-ray pair correlation functions is discussed qualitatively and quantitatively. The probable structural effects of non-additive forces are deduced from the behaviour of these derivatives, and some comments on quantum effects are given.
We present a catalogue of photoelectric UBV photometry and some spectral types for 610 stars in a field in Puppis centred at (l, b) = (245°, 0°). This catalogue reports results taken from the literature, as ...
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