Results 1 - 10 of 142675
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[en] To verify the structure description method taking the probability of component concentration distributions in alloys into account, it is necessary to answer the following question: do the geometrical shapes of component arrangement which are visible on the autoradiographs as dark spots determine the type and parameters of the probability distribution. To solve the problem, 14 autoradiographic models representing different shapes of labelled compounds have been prepared and measured. The results show that different structures have a different distribution of the same element
[en] This Letter presents a new sufficient condition for the existence, uniqueness and global robust asymptotic stability of the equilibrium point for neural networks with discrete time delays. The obtained condition can be easily verified as it is in terms of the network parameters only. Some numerical examples are given to compare our results with previous robust stability results derived in the literature
[en] We develop a Bayesian treatment of the problem of detecting unmodelled gravitational wave bursts using the new global network of interferometric detectors. We also compare this Bayesian treatment with existing coherent methods, and demonstrate that the existing methods make implicit assumptions on the distribution of signals that make them sub-optimal for realistic signal populations
[en] Developing countries' energy use is rapidly increasing, which affects global climate change and global and regional energy settings. Energy models are helpful for exploring the future of developing and industrialised countries. However, energy systems of developing countries differ from those of industrialised countries, which has consequences for energy modelling. New requirements need to be met by present-day energy models to adequately explore the future of developing countries' energy systems. This paper aims to assess if the main characteristics of developing countries are adequately incorporated in present-day energy models. We first discuss these main characteristics, focusing particularly on developing Asia, and then present a model comparison of 12 selected energy models to test their suitability for developing countries. We conclude that many models are biased towards industrialised countries, neglecting main characteristics of developing countries, e.g. the informal economy, supply shortages, poor performance of the power sector, structural economic change, electrification, traditional bio-fuels, urban-rural divide. To more adequately address the energy systems of developing countries, energy models have to be adjusted and new models have to be built. We therefore indicate how to improve energy models for increasing their suitability for developing countries and give advice on modelling techniques and data requirements
[en] We study the time dependence of the (average) interfacial separation between an elastic solid with a flat surface and a rigid solid with a randomly rough surface, squeezed together in a fluid. We use an analytical theory describing the fluid flow factors, based on the Persson contact mechanics theory and the Bruggeman effective medium theory, to calculate the removal of the fluid from the contacting interface of the two solids. In order to test this approach, we have performed simple squeeze-out experiments. The experimental results are compared to the theoretical predictions. (paper)
[en] In this note we derive the slow-roll and rapid-roll conditions for the minimally and nonminimally coupled spacelike vector fields. The function f(B2) represents the nonminimal coupling effect between vector fields and gravity, the f=0 case is the minimal coupling case. For a clear comparison with the scalar field, we define a new function F=±B2/12+f(B2), where B2=AμAμ, Aμ is the 'comoving' vector field. With reference to the slow-roll and rapid-roll conditions, we find the small-field model is more suitable than the large-field model in the minimally coupled vector field case. As a nonminimal coupling example, the F=0 case just has the same slow-roll conditions as the scalar fields.
[en] We use a scattering matrix approach to simulate the transmission through a hexagonal photonic crystal in the vicinity of the Dirac point. If the crystal is oriented so that the propagation direction perpendicular to the surface corresponds to the ΓK direction, no oblique transmission is possible for a very long (infinite) structure. For a finite structure with width, W, and length, L, the length dependence of the transmission is given by Ttotal=Γ0W/L. For Ttotal all waves with a wavevector parallel to the surface, k|| =n2π/W, described by a channel number, n, must be considered. We show the transmission at the Dirac point follows the given scaling law and this scaling law is related to the behavior of the individual channels. This leads to the establishment of a criterion for the maximum length for this scaling behavior when the total transmission reaches a constant value. We also compare this scaling behavior to the results in other frequency regions.
[en] In this paper a model for viscoanelastic isotropic material in the formalism of Kluitenberg's theory on mechanical relaxation phenomena is considered. Moreover an expression of the complex modulus is obtained to compare the results obtained with experimental data. In particular, by considering the results obtained from some authors of us in a previous paper, we shall use a different condition that allows to get the phenomenological and state coefficients both low and high frequencies. Finally, the results are applied to a supercooled m-toluidine in order to compare the experimental data and theoretical functions of frequency G1 and G2 so obtained.
[en] We model combined photoassociation and Feshbach resonances in a Bose-Einstein condensate, where the shared dissociation continuum allows for quantum interference in losses from the condensate, as well as a dispersive-like shift of resonance. A seemingly oversimplified model is revisited, explaining it as based on the limit of weakly bound molecules, reinforcing it with a comparison to numerical experiments that explicitly include dissociation to noncondensate modes, comparing it against the unitarity limit on condensate losses, and lastly, checking its universal implications. In particular, for a resonant laser and an off-resonant magnetic field, these numerical experiments reveal a rate limit on condensate losses that is larger for smaller condensate densities, approaches the rate limit for magnetoassociation alone near the Feshbach resonance, and agrees best with the analytical model for low density. Comparing the analytical rate limit against the unitary limit, which is set by the size of the condensate, agreement is found only for a limited range of near-resonant magnetic fields. Finally, for a resonant magnetic field and an off-resonant laser, the analytical shift of the Feshbach resonance is found to depend on the size of the Feshbach molecule, signifying nonuniversal physics in a strongly interacting system.