Gold and silver diffusion in germanium: a thermodynamic approach

Diffusion properties are technologically important in the understanding of semiconductors for the efficent formation of defined nanoelectronic devices. In the present study we employ experimental data to show that bulk materials properties (elastic and expansivity data) can be used to describe gold and silver diffusion in germanium for a wide temperature range (702–1177 K). Here we show that the so-called cBΩ model thermodynamic model, which assumes that the defect Gibbs energy is proportional to the isothermal bulk modulus and the mean volume per atom, adequately metallic diffusion in germanium

Time-difference between the electric field components of signals prior to major earthquakes

We present data demonstrating that the electric field components of low-frequency ( <= 1 Hz) precursory electric signals exhibit markedly different time evolutions. This difference, if properly measured, upon considering that the electromagnetic fields obey diffusion-type equations, is of profound importance since it can reveal the distance of the measuring site from the epicenter of the impending earthquake. (c) 2005 American Institute of Physics

Natural entropy fluctuations discriminate similar-looking electric signals emitted from systems of different dynamics

Complexity measures are introduced that quantify the change of the natural entropy fluctuations at different length scales in time series emitted from systems operating far from equilibrium. They identify impending sudden cardiac death (SD) by analyzing 15 min electrocardiograms, and comparing to those of truly healthy humans (H). These measures seem to be complementary to the ones suggested recently [Phys. Rev. E 70, 011106 (2004)] and altogether enable the classification of individuals into three categories: H, heart disease patients, and SD. All the SD individuals, who exhibit critical dynamics, result in a common behavior

Origin of the usefulness of the natural-time representation of complex time series

The concept of natural time turned out to be useful in revealing dynamical features behind complex time series including electrocardiograms, ionic current fluctuations of membrane channels, seismic electric signals, and seismic event correlation. However, the origin of this empirical usefulness is yet to be clarified. Here, it is shown that this time domain is in fact optimal for enhancing the signals in time-frequency space by employing the Wigner function and measuring its localization property