Nonlinear Smoluchowski slip velocity and micro-vortex generation

2002 ◽  
Vol 461 ◽  
pp. 229-238 ◽  
Author(s):  
Y. BEN ◽  
H.-C. CHANG
Keyword(s):  
Electric Field ◽  
Slip Velocity ◽  
Slip Length ◽  
Ionic Flux ◽  
Electrokinetic Flow ◽  
Surface Polarization ◽  
Counter Ions ◽  
Normal Electric Field ◽  
Porous Granule ◽  
Polarized Surface

When an electric field is applied across a conducting and ion-selective porous granule in an electrolyte solution, a polarized surface layer with excess counter-ions is created. The depth of this layer and the overpotential V across this layer are functions of the normal electric field j on the granule surface. By transforming the ionic flux equations and the Poisson equation into the Painlevé equation of the second type and by analysing the latter's asymptotic solutions, we derive a linear universal j–V correlation at large flux with an electrokinetic slip length β. The flux-induced surface polarization produces a nonlinear Smoluchowski slip velocity that can couple with the granule curvature to produce micro-vortices in micro-devices. Such vortices are impossible in irrotational electrokinetic flow with a constant zeta-potential and a linear slip velocity.

Linear growth of instabilities on a liquid metal under normal electric field

1993 ◽  
Vol 3 (8) ◽  
pp. 1201-1225 ◽  
Author(s):  
G. N�ron de Surgy ◽  
J.-P. Chabrerie ◽  
O. Denoux ◽  
J.-E. Wesfreid
Keyword(s):  
Liquid Metal ◽  
Electric Field ◽  
Linear Growth ◽  
Normal Electric Field

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

Examination of the Slip Boundary Condition by µ-PIV and Lattice Boltzmann Simulations

2002 ◽  
Author(s):  
Derek C. Tretheway ◽  
Luoding Zhu ◽  
Linda Petzold ◽  
Carl D. Meinhart
Keyword(s):  
Boundary Condition ◽  
Shear Rate ◽  
Channel Flow ◽  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Slip Length ◽  
Slip Boundary Condition ◽  
Slip Boundary ◽  
Lattice Boltzmann Simulations ◽  
Bounce Back

This work examines the slip boundary condition by Lattice Boltzmann simulations, addresses the validity of the Navier’s hypothesis that the slip velocity is proportional to the shear rate and compares the Lattice Boltzmann simulations to the experimental results of Tretheway and Meinhart (Phys. of Fluids, 14, L9–L12). The numerical simulation models the boundary condition as the probability, P, of a particle to bounce-back relative to the probability of specular reflection, 1−P. For channel flow, the numerically calculated velocity profiles are consistent with the experimental profiles for both the no-slip and slip cases. No-slip is obtained for a probability of 100% bounce-back, while a probability of 0.03 is required to generate a slip length and slip velocity consistent with the experimental results of Tretheway and Meinhart for a hydrophobic surface. The simulations indicate that for microchannel flow the slip length is nearly constant along the channel walls, while the slip velocity varies with wall position as a results of variations in shear rate. Thus, the resulting velocity profile in a channel flow is more complex than a simple combination of the no-slip solution and slip velocity as is the case for flow between two infinite parallel plates.

scholarly journals Normal electric field enhanced light-induced polarizations and magnetic detection of valley polarization in silicene

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
N. Shahabi ◽  
A. Phirouznia
Keyword(s):  
Electric Field ◽  
Light Emission ◽  
Polarized Light ◽  
Spin Current ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Normal Electric Field ◽  
Valley Polarization ◽  
Population Imbalance ◽  
Magnetic Detection

Abstract The role of staggered potential on light-induced spin and pseudo-spin polarization has been investigated in silicene. It has been shown that non-equilibrium spin and pseudo-spin polarizations are emerged in silicene sheet by applying an external perpendicular electric field in the presence of circularly polarized light emission. This electric field results in pseudo-spin resolved states very close to the Dirac points therefore could be considered as a pseudomagnetic field. It has been shown that staggered potential induced spin-valley locking and pseudo-spin resolved bands are responsible for the enhancement of the spin and pseudo-spin polarizations. Meanwhile, spin-valley locking suggests a coexistence of both spin and valley polarizations with nearly identical (or at least proportional) population imbalance at low Fermi energies which could be employed for magnetic detection of the valley polarization. It has been shown that spin-valley locking results in the protection of the spin polarizations against the relaxations in elastic scattering regime. In addition, the results indicate that the pseudo-spin current can be generated by the circularly polarized light which could be explained by asymmetric light absorption of the states in k-space.

Simultaneously Homogenized Electric Field and Ionic Flux for Reversible Ultrahigh-Areal-Capacity Li Deposition

Nano Letters ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 5662-5669
Author(s):  
Lihan Zhang ◽  
Xiaoguang Yin ◽  
Sibo Shen ◽  
Yang Liu ◽  
Tong Li ◽  
...  
Keyword(s):  
Electric Field ◽  
Ionic Flux ◽  
Areal Capacity

Inverse Problems in Non-Newtonian Electrokinetic Flows in Microchannel Networks

Volume 3 ◽  
2004 ◽  
Author(s):  
William B. Zimmerman ◽  
Julia M. Rees ◽  
Thomas J. Craven
Keyword(s):  
Slip Velocity ◽  
Pressure Profile ◽  
Carreau Fluid ◽  
Boundary Slip ◽  
Electrokinetic Flow ◽  
Nonlinear Viscosity ◽  
Relaxation Time Scale ◽  
Electrokinetic Flows ◽  
Electrokinetic Motion ◽  
End Wall

A model of the electrokinetic flow of a fluid with a nonlinear viscosity of the Carreau type is simulated by finite element methods in a microchannel T-junction. The simulations accelerate the fluid from rest using the model for boundary slip velocity imposed due to a Debye double layer motion proposed by Zimmerman and MacInnes (2003). The simulations demonstrate an interval of the transient evolution of the end wall pressure profile that scales proportionally with the Reynolds number. The shape of the steady state profile is shown to be sensitive to the relaxation time scale characterizing the shear rate dependence of a Carreau fluid. Consequently, this flow regime can be taken as a paradigm viscometric flow for electrokinetic motion.

Augmentation of mixing across a diaphragm in a normal electric field

1978 ◽  
Vol 21 (11) ◽  
pp. 2118 ◽  
Author(s):  
James F. Hoburg ◽  
Farrokh Malihi
Keyword(s):  
Electric Field ◽  
Normal Electric Field
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