Study of Trapping and Recombination In a-Si:H By Means of Infrared Enhancement Spectra of Photoconductivity

1986 ◽  
Vol 70 ◽  
Author(s):  
Wu Wenhao ◽  
Qiu Changhua ◽  
Zhao Shifu ◽  
Han Daxing
Keyword(s):  
Steady State ◽  
Pump Light ◽  
Time Interval ◽  
Probe Light ◽  
Deep Traps ◽  
Multiple Trapping ◽  
Temperature Dependences ◽  
Pass Through ◽  
Non Equilibrium

ABSTRACTIR re-excitation of non-equilibrium carriers in undoped a-Si:H has been used to probe the profile of the distribution of deep traps. In a dualbeam experiment, after turning off a pump light, the trapped carriers are re-excited by an IR probe light which causes the photoconductivity(PC) to pass through a maximum, σmax, before settling down towards its steady state value, σs. σmax depends on the time interval td between turning off the pump light and turning on the probe light in a manner Δσ=σmax-σs∞td-α(T) Based on the multiple trapping (MT) model, the distribution of deep traps has been deduced from the temperature dependences of α(T).

The Effect of Light Soaking on the Photoconductivity Response in A-SI:H

1986 ◽  
Vol 70 ◽  
Author(s):  
Qiu Changhua ◽  
Wu Wenhao ◽  
Zhao Shifu ◽  
Han Daxing
Keyword(s):  
Steady State ◽  
Response Time ◽  
Fermi Level ◽  
Low Temperatures ◽  
Deep Traps ◽  
Temperature Dependences ◽  
The Difference ◽  
Shallow Traps ◽  
Photoconductivity Response ◽  
Effect Of Light

ABSTRACTThe temperature dependences of response time tr and steady state photoconductivity (PC) were used to deduce the DOS at energies above the dark Fermi level. The tr and PC of annealled state A and light soaked state B were measured from 115K to 300K. Light soaking causes degradation of PC. Compared with state A, the PC response of state B is faster at low temperatures, but is slower at high temperatures. The difference between state A and state B was interpreted by a decrease of shallow traps and an increase of deep traps.

Supradegeneracy and the Second Law of Thermodynamics

2020 ◽  
Vol 45 (2) ◽  
pp. 121-132
Author(s):  
Daniel P. Sheehan
Keyword(s):  
Steady State ◽  
Statistical Mechanics ◽  
Population Inversion ◽  
Laboratory Experiments ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Boltzmann Factor ◽  
Energy Currents ◽  
Non Equilibrium

AbstractCanonical statistical mechanics hinges on two quantities, i. e., state degeneracy and the Boltzmann factor, the latter of which usually dominates thermodynamic behaviors. A recently identified phenomenon (supradegeneracy) reverses this order of dominance and predicts effects for equilibrium that are normally associated with non-equilibrium, including population inversion and steady-state particle and energy currents. This study examines two thermodynamic paradoxes that arise from supradegeneracy and proposes laboratory experiments by which they might be resolved.

scholarly journals Modules or Mean-Fields?

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 552 ◽  
Author(s):  
Thomas Parr ◽  
Noor Sajid ◽  
Karl J. Friston
Keyword(s):  
Steady State ◽  
Message Passing ◽  
Mean Field Theory ◽  
Functional Anatomy ◽  
Mean Field ◽  
State Density ◽  
Stochastic Dynamical Systems ◽  
Conditional Independency ◽  
The Brain ◽  
Non Equilibrium

The segregation of neural processing into distinct streams has been interpreted by some as evidence in favour of a modular view of brain function. This implies a set of specialised ‘modules’, each of which performs a specific kind of computation in isolation of other brain systems, before sharing the result of this operation with other modules. In light of a modern understanding of stochastic non-equilibrium systems, like the brain, a simpler and more parsimonious explanation presents itself. Formulating the evolution of a non-equilibrium steady state system in terms of its density dynamics reveals that such systems appear on average to perform a gradient ascent on their steady state density. If this steady state implies a sufficiently sparse conditional independency structure, this endorses a mean-field dynamical formulation. This decomposes the density over all states in a system into the product of marginal probabilities for those states. This factorisation lends the system a modular appearance, in the sense that we can interpret the dynamics of each factor independently. However, the argument here is that it is factorisation, as opposed to modularisation, that gives rise to the functional anatomy of the brain or, indeed, any sentient system. In the following, we briefly overview mean-field theory and its applications to stochastic dynamical systems. We then unpack the consequences of this factorisation through simple numerical simulations and highlight the implications for neuronal message passing and the computational architecture of sentience.

Li Uptake in Carbon Nanotube Systems: A First Principles Investigation

2001 ◽  
Vol 706 ◽  
Author(s):  
Vincent Meunier ◽  
Jeremy Kephart ◽  
Christopher Roland ◽  
Jerry Bernholc
Keyword(s):  
Carbon Nanotube ◽  
Ab Initio ◽  
Ball Milling ◽  
First Principles ◽  
Topological Defects ◽  
Ion Bombardment ◽  
Ion Uptake ◽  
Li Ion ◽  
Pass Through ◽  
Non Equilibrium

AbstractCarbon nanotube systems can substantially increase their capacity for Li ion uptake, provided that the nanotube interiors become accessible to the ions. We examine theoretically, with ab initio simulations, the ability of Li ions to enter a nanotube interior. While our calculations show that it is quite unlikely for the ions to pass through pristine nanotubes, they are much more likely to enter via large-sized topological defects consisting of at least 9- or more membered rings. It is unlikely that such defects are formed spontaneously, but it may be possible to induce such topological defects by violent non-equilibrium means such as ball milling, chemical means and/or ion bombardment. Indeed, recent experiments on ball milled nanotube samples do report an important increase in the Li ion uptake.

scholarly journals Lifshitz hydrodynamics at generic z from a moving black brane

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Aruna Rajagopal ◽  
Larus Thorlacius
Keyword(s):  
Field Theory ◽  
Steady State ◽  
Critical Exponent ◽  
Stress Tensor ◽  
Perfect Fluid ◽  
Scale Invariance ◽  
Linear Momentum ◽  
Black Brane ◽  
Dilaton Gravity ◽  
Non Equilibrium

Abstract A Lifshitz black brane at generic dynamical critical exponent z > 1, with non-zero linear momentum along the boundary, provides a holographic dual description of a non-equilibrium steady state in a quantum critical fluid, with Lifshitz scale invariance but without boost symmetry. We consider moving Lifshitz branes in Einstein-Maxwell-Dilaton gravity and obtain the non-relativistic stress tensor complex of the dual field theory via a suitable holographic renormalisation procedure. The resulting black brane hydrodynamics and thermodynamics are a concrete holographic realization of a Lifshitz perfect fluid with a generic dynamical critical exponent.

Thermal Diffusivity of the Mott Insulator Ca2RuO4 in a Non-equilibrium Steady State

2021 ◽  
Vol 90 (6) ◽  
pp. 063601
Author(s):  
Shuji Kawasaki ◽  
Akitoshi Nakano ◽  
Hiroki Taniguchi ◽  
Hai Jun Cho ◽  
Hiromichi Ohta ◽  
...  
Keyword(s):  
Steady State ◽  
Thermal Diffusivity ◽  
Mott Insulator ◽  
Non Equilibrium

scholarly journals THE ACCUMULATION OF ELECTROLYTES

1932 ◽  
Vol 15 (6) ◽  
pp. 667-689 ◽  
Author(s):  
W. J. V. Osterhout ◽  
W. M. Stanley
Keyword(s):  
Steady State ◽  
Osmotic Pressure ◽  
Aqueous Phase ◽  
Thermodynamic Potential ◽  
Ph Value ◽  
Molecular Form ◽  
External Solution ◽  
Aqueous Layer ◽  
The Difference ◽  
Pass Through

Inasmuch as attempts to explain accumulation by the Donnan principle have failed in the case of Valonia, a hypothesis of the steady state has been formulated to explain what occurs. In order to see whether this hypothesis is in harmony with physico-chemical laws attempts have been made to imitate its chief features by means of a model. The model consists of a non-aqueous layer (representing the protoplasmic surface) placed between an alkaline aqueous phase (representing the external solution) and a more acid aqueous phase (representing the cell sap). The model reproduces most of the features of the hypothesis. Attention may be called to the following points. 1. The semipermeable surface is a continuous non-aqueous phase. 2. Potassium penetrates by combining with an acid HX in the non-aqueous layer to form KX which in turn reacts with an acid HA in the sap to form KA. Since KX is little dissociated in the non-aqueous layer potassium appears to pass through it chiefly in molecular form. 3. The internal composition depends on permeability, e.g., sodium penetrates less rapidly than potassium and in consequence potassium predominates over sodium in the "artificial sap." The order of penetration in the model is the same as in Valonia, i.e., K > Na > Ca > Mg, and Cl > SO4, but the quantitative resemblance is not close, e.g., the difference between potassium and sodium, and chloride and sulfate is much less in the model. 4. The formation of KA and NaA in the sap raises its osmotic pressure and water enters. 5. The concentration of potassium and sodium and the osmotic pressure become much greater inside than outside. For example, potassium may become 200 times as concentrated inside as outside. 6. No equilibrium occurs but a steady state is reached in which water and salt enter at the same rate so that the composition of the sap remains constant as its volume increases. 7. Since no equilibrium occurs there is a difference of thermodynamic potential between inside and outside. At the start the thermodynamic potential of KOH is much greater outside than inside. This difference gradually diminishes and in the steady state has about the same value as in Valonia. The difference in pH value between the internal and external solutions is also similar in both cases (about 2 pH units). 8. Accumulation does not depend on the presence of molecules or ions inside which are unable to pass out. One important feature of the hypothesis is not seen in the model: this is the exchange of HCO3 for Cl-. Experiments on this point are in progress.

A steady-state non-equilibrium molecular dynamics approach for the study of evaporation processes

2013 ◽  
Vol 139 (13) ◽  
pp. 134701 ◽  
Author(s):  
Jianguo Zhang ◽  
Florian Müller-Plathe ◽  
Méziane Yahia-Ouahmed ◽  
Frédéric Leroy
Keyword(s):  
Molecular Dynamics ◽  
Steady State ◽  
Non Equilibrium Molecular Dynamics ◽  
Non Equilibrium
Sign in / Sign up

Export Citation Format

Share Document