scholarly journals Time-dependent screening of a positive charge distribution in metals: Excitons on an ultrashort time scale

2000 ◽  
Vol 62 (20) ◽  
pp. 13464-13471 ◽  
Author(s):  
Wolf-Dieter Schöne ◽  
Walter Ekardt
Keyword(s):  
Charge Distribution ◽  
Time Scale ◽  
Positive Charge ◽  
Time Dependent

scholarly journals On time dependent multistep dynamic processes

1991 ◽  
Vol 43 (1) ◽  
pp. 51-61
Author(s):  
Ferenc Szidarovszky ◽  
Ioannis K. Argyros
Keyword(s):  
Topological Space ◽  
Discrete Time ◽  
Difference Equations ◽  
Time Scale ◽  
Time Dependent ◽  
Dynamic Processes ◽  
Monotone Convergence ◽  
Speed Of Convergence ◽  
Nonlinear Difference Equations ◽  
Ordered Topological Space

The discrete time scale Liapunov theory is extended to time dependent, higher order, nonlinear difference equations in a partially ordered topological space. The monotone convergence of the solution is examined and the speed of convergence is estimated.

On the Cherenkov radiation from extended charge distributions

2000 ◽  
Vol 77 (10) ◽  
pp. 775-784 ◽  
Author(s):  
M Villavicencio ◽  
J L Jiménez ◽  
JAE Roa-Neri
Keyword(s):  
Explicit Expression ◽  
Charge Distribution ◽  
Constant Velocity ◽  
Cherenkov Radiation ◽  
Poynting Vector ◽  
Time Dependent ◽  
Spherically Symmetric ◽  
Charge Distributions ◽  
Extended Charge ◽  
A Charge

In this work the Cherenkov effect for extended charge distributions is analyzed using two different methods. In the first method, the Poynting vector is employed to determine the energy radiated, whereas in the second one, we apply the idea of generating time-dependent elemental dipoles, induced by a charge distribution moving with constant velocity, inside a material medium. An explicit expression for the Cherenkov radiation generated by some different kinds of spherically symmetric charge, travelling inside a medium, is obtained.PACS Nos.: 03.50.De, 41.20.Bt, 41.60.-m, 41.60.Bq

scholarly journals Positive charge distribution in (benzene)1(toleune)2+ and (benzene)2(toluene)1+ studied by photodissociation spectroscopy

2002 ◽  
Vol 117 (23) ◽  
pp. 10648-10653 ◽  
Author(s):  
Yoshiya Inokuchi ◽  
Kazuhiko Ohashi ◽  
Hiroshi Sekiya ◽  
Nobuyuki Nishi
Keyword(s):  
Charge Distribution ◽  
Positive Charge

Time scale of dynamic heterogeneity in model ionic liquids and its relation to static length scale and charge distribution

2015 ◽  
Vol 17 (43) ◽  
pp. 29281-29292 ◽  
Author(s):  
Sang-Won Park ◽  
Soree Kim ◽  
YounJoon Jung
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Charge Distribution ◽  
Power Law ◽  
Structural Relaxation ◽  
Time Scale ◽  
Length Scale ◽  
Dynamic Heterogeneity ◽  
General Power

We find a general power-law behavior: , where ζdh ≈ 1.2 for all the ionic liquid models, regardless of charges and the length scale of structural relaxation.

Excitation and resonance of acoustic-gravity waves in a column of stratified, bubbly magma

2016 ◽  
Vol 797 ◽  
pp. 431-470 ◽  
Author(s):  
Leif Karlstrom ◽  
Eric M. Dunham
Keyword(s):  
Mass Exchange ◽  
Time Scale ◽  
Lava Lake ◽  
Time Dependent ◽  
Mathematical Framework ◽  
Resonance Frequencies ◽  
Fluid Properties ◽  
Excitation Processes ◽  
Non Equilibrium ◽  
Active Volcanoes

Oscillations of magma in volcanic conduits are thought to be the source of certain seismic and infrasonic signals observed near active volcanoes. However, the multiphase and stratified nature of magma within the conduit complicates the calculation of resonant modes that is required to interpret observations. Here we present a linearized mathematical framework to describe small-amplitude oscillations and waves in a stably stratified column of two-phase magma (liquid melt and gas bubbles) with a traction-free upper surface (a lava lake). We explore the role of time-dependent mass exchange between the phases, depth-varying fluid properties and gravity on the modes of oscillation of inviscid magma within an axisymmetric, vertical conduit. Non-equilibrium phase exchange, which we refer to as bubble growth and resorption (BGR), is parameterized by introduction of a kinetic time scale quantifying mass exchange between the liquid and gas phases that evolves the mixture towards a state of thermodynamic equilibrium. Using a provably stable finite difference method, we solve the eigenvalue problem for the resonance frequencies, decay rates, and spatial structure of the conduit eigenmodes. The numerical method is then extended to time-domain simulations of waves excited by internal volumetric sources in the conduit or forces applied to the surface of the lava lake. We connect time-dependent wave propagation simulations to the modal analysis by identifying the primary modes that are excited by representative excitation processes. Waves propagating through bubbly magma are dispersive, and their behaviour is determined by three dimensionless parameters. One quantifies the importance of buoyancy and gravitational restoring forces relative to compressibility, the second quantifies differences between fluid properties (e.g. mixture compressibility) under equilibrium and non-equilibrium conditions, and the third compares the wave period to the BGR time scale. Pronounced depth variations in background fluid properties, such as the transition from liquid melt with dissolved volatiles at the high pressures at depth to bubbly magma above the gas exsolution depth, segment the conduit into distinct regions. The longest-period modes, which are expressed with the largest amplitudes for typical excitation processes, are most sensitive to the length of the bubbly region and properties of the bubbly magma within it. While the boundary condition at the bottom of the conduit determines whether the fundamental mode is affected by the total conduit length, modes localized above the exsolution depth are remarkably insensitive to the overall conduit length. Our analysis suggests that parameters affecting eruption style, such as total volatile content and kinetic time scales of BGR, along with excitation source characteristics, are imprinted on long-period seismic and infrasonic signals at active volcanoes.

Analysis of follow-up data

2020 ◽  
pp. 93-118
Author(s):  
Bendix Carstensen
Keyword(s):  
Data Collection ◽  
Time Scale ◽  
Poisson Regression ◽  
Time Dependent ◽  
Follow Up Study ◽  
Dependent Variables ◽  
The Status ◽  
Over Time

This chapter assesses the analysis and representation of follow-up data. follow-up refers to the process of monitoring persons over time for occurrence of a (set of) prespecified event(s). Practical data collection is often via look-up in registers or databases. The basic requirements for recordings in a follow-up study include date of entry to the study, date of exit from the study, and the status of the person at the exit date. The chapter then explains the likelihood from a follow-up study and why one can analyse rates using Poisson regression. The likelihood contribution from a single person's follow-up can be subdivided in contributions from subintervals of the follow-up. The chapter details the task of splitting the follow-up time along a time-scale. Finally, it considers time-dependent variables.

Surface spreading of charge due to ohmic conduction

1985 ◽  
Vol 399 (1817) ◽  
pp. 277-293 ◽  
Keyword(s):  
Charge Distribution ◽  
Boundary Plane ◽  
Time Dependent ◽  
Interface Plane ◽  
Characteristic Velocity ◽  
Ohmic Conduction ◽  
Exact Analytical Solutions ◽  
Initial Charge ◽  
Dependent Potential ◽  
Surface Spreading

Exact analytical solutions are presented for the time-dependent charge and potential distributions due to the surface spreading of any initial charge distribution by ohmic conduction on the plane interface between two isotropic insulators of zero bulk conductivity. The solutions are applicable to systems of insulators that extend to infinity, which may include electrodes provided these have infinite surfaces that are normal to the boundary plane between the insulators. The solutions reduce charge spreading problems to ones of simple electrostatics where the time-dependent potential can be treated as being due to the initial charge distribution receding from the interface plane with a constant characteristic velocity. Solutions for the behaviour of various initial charge distributions are given.

Transient Behavior of Phoioxcurrent in a-Si :H Solar Cells

1986 ◽  
Vol 70 ◽  
Author(s):  
Gad Cuang ◽  
Miao Qing ◽  
Cao Baocheng ◽  
Guo Xiaoqin ◽  
Dai Guocai
Keyword(s):  
Solar Cells ◽  
Space Charge ◽  
Charge Distribution ◽  
Photon Energy ◽  
Transient Behavior ◽  
Time Dependent ◽  
Photocurrent Response ◽  
Excitation Light ◽  
Pulsed Excitation ◽  
Space Charge Distribution

AbstrctTime-dependent photocurrent response by the monochromatic square-pulsed excitation light of different wavelenths has been studied on the PIN a-Si:H solar cells. The experiments show that the shape of the photocurrent transient is distinctly changed by varying the photon energy of the excitation light and the applied biases. Our results can be explained by the relaxation of space charge distribution in the i-layer.

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