VOLTAGE AND FREQUENCY DEPENDENCE OF CHARGE TRANSFER BY PRESTIN: AN ELECTRO-DIFFUSION MODEL

2009 ◽  
Author(s):  
S. SUN ◽  
B. FARRELL ◽  
M. CHANA ◽  
S. FENG ◽  
G. OSTER ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Frequency Dependence ◽  
Diffusion Model

scholarly journals Voltage and frequency dependence of prestin-associated charge transfer

2009 ◽  
Vol 260 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Sean X. Sun ◽  
Brenda Farrell ◽  
Matthew S. Chana ◽  
George Oster ◽  
William E. Brownell ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Frequency Dependence

scholarly journals On the processes of migration and diffusion in the systems with solid-state reagents

2020 ◽  
Vol 10 (2) ◽  
pp. 219-227
Author(s):  
Viacheslav Barsukov ◽  
Volodymyr Khomenko ◽  
Oksana Chernysh
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Diffusion Model ◽  
Diffusion Processes ◽  
Solid Phase ◽  
Electrode Processes ◽  
Bulk Solid ◽  
Efficient Diffusion ◽  
The Difference ◽  
And Migration

This paper deals with peculiarities of diffusion and migration in electrochemical systems with solid-state reagents (ESSSR). Contradictions of the diffusion model are analyzed. It is the difference of applied potentials and the corresponding electric field strength in the bulk solid phase and at the interfaces which is the primary driving force of charge transfer in ESSSR. The time characteristic of diffusion processes is not comparable to the duration of electrode processes at charging/discharging of batteries and especially electrochemical capacitors. In many real systems involving ESSSR, the process of diffusion in solid phase is absent. Examples of charge transfer processes in ESSSR (nickel hydroxide electrode, sparingly soluble quinoid compounds, Li+ intercalation in graphite, etc.) are considered, and the processes are explained using the Grothuss, tunnel and other migration mechanisms. It is shown in this paper that the linear relationship between peak currents in voltammetric curves and the square root of potential scan rate cannot be presented as an ultimate support of the diffusion model, but as а more universal property of ESSSR. In this aspect, the efficient diffusion coefficient, Deff, could be at best discussed, not to distort the ideas of charge-transfer migration mechanisms in the ESSSR.

Glass Transition Singularities and Slow Relaxation

1994 ◽  
Vol 367 ◽  
Author(s):  
T. Odagaki ◽  
J. Matsui ◽  
Y. Hiwatari
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Frequency Dependence ◽  
Diffusion Model ◽  
Fluid Phase ◽  
Dynamics Simulation ◽  
Glass Transition Point ◽  
Kinetic Transition ◽  
Diffusive Dynamics ◽  
Unified View

AbstractGeneralized susceptibility for the binary soft-sphere mixtures is computed for the frequency range including both the a and β peaks in a supercooled fluid phase with a superlong-time molecular dynamics simulation. It is shown that the a peak has a non-Debye type frequency dependence and the β peak is essentially of a Debye-type. The slow dynamics is analyzed on the basis of the trapping diffusion model which takes account of two types of diffusive dynamics. With the use of the coherent medium approximation, the frequency dependence of dynamical quantities are shown to agree with the observation. The primary relaxation time is shown to exponentially diverge at a certain temperature below the glass transition point, in line with the Vogel-Fulcher equation. A unified view for the Vogel-Fulcher temperature, the glass transition temperature and the kinetic transition temperature is give on the basis of the trapping diffusion model.

scholarly journals A Fractional Diffusion Model for Dye-Sensitized Solar Cells

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2966
Author(s):  
B. Maldon ◽  
N. Thamwattana
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Diffusion Model ◽  
Numerical Solutions ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Fractional Diffusion ◽  
Diffusion Equations ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Dye-sensitized solar cells have continued to receive much attention since their introduction by O’Regan and Grätzel in 1991. Modelling charge transfer during the sensitization process is one of several active research areas for the development of dye-sensitized solar cells in order to control and improve their performance and efficiency. Mathematical models for transport of electron density inside nanoporous semiconductors based on diffusion equations have been shown to give good agreement with results observed experimentally. However, the process of charge transfer in dye-sensitized solar cells is complicated and many issues are in need of further investigation, such as the effect of the porous structure of the semiconductor and the recombination of electrons at the interfaces between the semiconductor and electrolyte couple. This paper proposes a new model for electron transport inside the conduction band of a dye-sensitized solar cell comprising of TiO 2 as its nanoporous semiconductor. This model is based on fractional diffusion equations, taking into consideration the random walk network of TiO 2 . Finally, the paper presents numerical solutions of the fractional diffusion model to demonstrate the effect of the fractal geometry of TiO 2 on the fundamental performance parameters of dye-sensitized solar cells, such as the short-circuit current density, open-circuit voltage and efficiency.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Direct imaging of charge transfer

1996 ◽  
Vol 54 ◽  
pp. 680-681
Author(s):  
Yimei Zhu ◽  
J. Tafto
Keyword(s):  
Charge Transfer ◽  
Electron Diffraction ◽  
Scattering Amplitude ◽  
High Temperature Superconductors ◽  
Charge Carriers ◽  
Image Charge ◽  
Net Charge ◽  
Long Time ◽  
Electron Holes ◽  
First Time

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.

A new lithium diffusion model in layered oxides based on asymmetric but reversible transition metal migration

2020 ◽  
Vol 13 (4) ◽  
pp. 1269-1278 ◽  
Author(s):  
Kyojin Ku ◽  
Byunghoon Kim ◽  
Sung-Kyun Jung ◽  
Yue Gong ◽  
Donggun Eum ◽  
...  
Keyword(s):  
Transition Metal ◽  
Diffusion Model ◽  
Layered Oxides ◽  
Layered Oxide ◽  
Reversible Transition ◽  
Lithium Diffusion ◽  
Metal Migration

We propose a new lithium diffusion model involving coupled lithium and transition metal migration, peculiarly occurring in a lithium-rich layered oxide.

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