Search results for "Debye"
showing 8 items of 78 documents
The non-equilibrium charge screening effects in diffusion-driven systems with pattern formation.
2011
The effects of non-equilibrium charge screening in mixtures of oppositely charged interacting molecules on surfaces are analyzed in a closed system. The dynamics of charge screening and the strong deviation from the standard Debye-Huckel theory are demonstrated via a new formalism based on computing radial distribution functions suited for analyzing both short-range and long-range spacial ordering effects. At long distances the inhomogeneous molecular distribution is limited by diffusion, whereas at short distances (of the order of several coordination spheres) by a balance of short-range (Lennard-Jones) and long-range (Coulomb) interactions. The non-equilibrium charge screening effects in …
Speciation Studies of Bifunctional 3-Hydroxy-4-Pyridinone Ligands in the Presence of Zn2+ at Different Ionic Strengths and Temperatures
2019
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Slide electrification: charging of surfaces by moving water drops.
2019
We investigate the charge separation caused by the motion of a water drop across a hydrophobic, insulating solid surface. Although the phenomenon of liquid charging has been consistently reported, these reports are primarily observational, results are difficult to reproduce, and no quantitative theory has been developed. In this work, we address both the experimental and theoretical sides of this problem. We reproducibly measure the charge gained by water drops sliding down a substrate, and we outline an analytical theory to describe this charging process. As an experimental system, we choose water drops moving down an inclined plane of glass hydrophobized with perfluoro octadecyltrichloros…
β-Relaxation and low-temperature specific heat in (KBr)1?x(KCN)x
1990
The specific heat in (KBr)1−x(KCN)x has been measured for concentrations 0.00≦x≦0.93 and for temperatures 2 K≦T≦50 K. In addition, the dipolar relaxation phenomena were studied using dielectric spectroscopy. The relaxation behaviour was parametrized assuming a Gaussian distribution of energy barriers and the mean activation energies, the distribution widths, and the attempt frequencies have been determined as a function of the CN− concentration. With these parameters the linear and the excess specific heat contributions were calculated and compared to the calorimetric results.
A real-space approach to the analysis of stacking faults in close-packed metals: Modelling and Q-space feedback Longo Alessandro
2020
An R-space approach to the simulation and fitting of a structural model to the experimental pair distribution function is described, to investigate the structural disorder (distance distribution and stacking faults) in close-packed metals. This is carried out by transferring the Debye function analysis into R space and simulating the low-angle and high-angle truncation for the evaluation of the relevant Fourier transform. The strengths and weaknesses of the R-space approach with respect to the usual Q-space approach are discussed.
Low temperature heat capacity of phononic crystal membranes
2016
Phononic crystal (PnC) membranes are a promising solution to improve sensitivity of bolometric sensor devices operating at low temperatures. Previous work has concentrated only on tuning thermal conductance, but significant changes to the heat capacity are also expected due to the modification of the phonon modes. Here, we calculate the area-specific heat capacity for thin (37.5 - 300 nm) silicon and silicon nitride PnC membranes with cylindrical hole patterns of varying period, in the temperature range 1 - 350 mK. We compare the results to two- and three-dimensional Debye models, as the 3D Debye model is known to give an accurate estimate for the low-temperature heat capacity of a bulk sam…
Highly occupied gauge theories in 2 + 1 dimensions : a self-similar attractor
2019
Motivated by the boost-invariant Glasma state in the initial stages in heavy-ion collisions, we perform classical-statistical simulations of SU(2) gauge theory in 2+1 dimensional space-time both with and without a scalar field in the adjoint representation. We show that irrespective of the details of the initial condition, the far-from-equilibrium evolution of these highly occupied systems approaches a unique universal attractor at high momenta that is the same for the gauge and scalar sectors. We extract the scaling exponents and the form of the distribution function close to this non-thermal fixed point. We find that the dynamics are governed by an energy cascade to higher momenta with sc…