Numerical Studies of Signal Amplification in a BaTiO3:Ce Crystal with an Applied Electric Field

1997 ◽  
Vol 06 (03) ◽  
pp. 349-360
Author(s):  
Ping Xie ◽  
Jian-Hua Dai ◽  
Peng-Ye Wang ◽  
Hong-Jun Zhang
Keyword(s):  
Electric Field ◽  
Input Signal ◽  
Applied Electric Field ◽  
Signal Amplification ◽  
Applied Field ◽  
Critical Role ◽  
Three Dimensional ◽  
Pump Intensity ◽  
Numerical Studies ◽  
Fanning Effect

The gain and the spatial fidelity of signal amplification in photorefractive BaTiO 3: Ce , with considerations of the effect of the externally applied electric field and the fanning effect (or noise), are numerically studied using a three-dimensional analysis. Although the gain of the signal can be enhanced with the applied field, its spatial fidelity is greatly reduced, especially at a small angle between the two propagation directions of the pump and signal beams. The fanning effect reduces the spatial fidelity, and the smaller the input signal to pump intensity ratio is, the smaller the fidelity becomes. At large magnitudes of the applied field, the applied field plays a critical role in the reduction of the fidelity of the signal and the fanning effect on the fidelity is negligible.

scholarly journals Electrorheology of a dilute emulsion of surfactant-covered drops

2019 ◽  
Vol 881 ◽  
pp. 524-550 ◽  
Author(s):  
Antarip Poddar ◽  
Shubhadeep Mandal ◽  
Aditya Bandopadhyay ◽  
Suman Chakraborty
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Shear Thickening ◽  
Field Configuration ◽  
Uniform Electric Field ◽  
Surface Tension Gradient ◽  
Drop Surface ◽  
Flow Perturbation

We investigate the effects of surfactant coating on a deformable viscous drop under the combined action of shear flow and a uniform electric field. Employing a comprehensive three-dimensional approach, we analyse the non-Newtonian shearing response of the bulk emulsion in the dilute suspension regime. Our results reveal that the location of the peak surfactant accumulation on the drop surface may get shifted from the plane of shear to a plane orthogonal to it, depending on the tilt angle of the applied electric field and strength of the electrical stresses relative to their hydrodynamic counterparts. The surfactant non-uniformity creates significant alterations in the flow perturbation around the drop, triggering modulations in the bulk shear viscosity. Overall, the shear-thinning or shear-thickening behaviour of the emulsion appears to be greatly influenced by the interplay of surface charge convection and Marangoni stresses. We show that the balance between electrical and hydrodynamic stresses renders a vanishing surface tension gradient on the drop surface for some specific shear rates, rendering negligible alterations in the bulk viscosity. This critical condition largely depends on the electrical permittivity and conductivity ratios of the two fluids and orientation of the applied electric field. Also, the physical mechanisms of charge convection and surface deformation play their roles in determining this critical shear rate. As a consequence, we obtain new discriminating factors, involving electrical property ratios and the electric field configuration, which govern the same. Consequently, the surfactant-induced enhancement or attenuation of the bulk emulsion viscosity depends on the electrical conductivity and permittivity ratios. The concerned description of the drop-level flow physics and its connection to the bulk rheology of a dilute emulsion may provide a fundamental understanding of a more complex emulsion system encountered in industrial practice.

THE RESPONSE OF STARCH/GELATIN/GLYCERIN AQUEOUS ELECTRORHEOLOGICAL ELASTOMER TO APPLIED ELECTRIC FIELD

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1449-1455 ◽  
Author(s):  
LINGXIANG GAO ◽  
XIAOPENG ZHAO
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Applied Field ◽  
Weight Fraction ◽  
Compression Modulus ◽  
Composite Systems ◽  
Water Matrix ◽  
Dc Electric Field

The aqueous ER elastomers, containing crude organic starch particles which dispersed in gelatin/glycerin/water matrix, were prepared with or without the applied DC electric field. The responses of the composite systems to the electric field were tested by the compression modulus and resistance of the elastomers. The result shows that they are enhanced and controlled evidently under an applied DC electric field. The strongest responses appear at 25% weight fraction of starch. In addition, the increment modulus of the elastomer increases with the strength of the applied field within 0.5~1.5 kV/mm, while after the field is stronger than 1.5 kV/mm it doesn't increase with field, appearing "saturation".

scholarly journals Nonlinear neutral inclusions: assemblages of coated ellipsoids

2015 ◽  
Vol 2 (4) ◽  
pp. 140394 ◽  
Author(s):  
Silvia Jiménez Bolaños ◽  
Bogdan Vernescu
Keyword(s):  
Thermal Conductivity ◽  
Electric Field ◽  
Applied Electric Field ◽  
Applied Field ◽  
Nonlinear Materials

The problem of determining nonlinear neutral inclusions in (electrical or thermal) conductivity is considered. Neutral inclusions, inserted in a matrix containing a uniform applied electric field, do not disturb the field outside the inclusions. The well-known Hashin-coated sphere construction is an example of a neutral inclusion. In this paper, we consider the problem of constructing neutral inclusions from nonlinear materials. In particular, we discuss assemblages of coated ellipsoids. The proposed construction is neutral for a given applied field.

The cataphoresis of spherical, solid non-conducting particles in a symmetrical electrolyte

1950 ◽  
Vol 203 (1075) ◽  
pp. 514-533 ◽  
Keyword(s):  
Zeta Potential ◽  
Theoretical Analysis ◽  
Field Strength ◽  
Electric Field ◽  
Applied Electric Field ◽  
Applied Field ◽  
Considerable Importance ◽  
Steady Velocity ◽  
General Method ◽  
Charged Spheres

A theoretical analysis is given of the motion of solid non-conducting charged spheres through symmetrical electrolytes, under the action of an applied electric field. It is shown that the steady velocity of translation U may be written in the alternative forms U = Ʃ ∞ 1 c v Q v = Ʃ ∞ 1 d v ζ v , where Qe denotes the charge on a sphere and ζ the zeta-potential; the coefficients c v and d v are proportional to the applied field strength and depend upon the radius of the particle and the concentrations, valencies and mobilities of the ions in the electrolyte. A general method is given for calculating the c v and d v and the first four coefficients of each series found explicitly. Some quite general properties of the c v are also deduced. It is shown that under certain conditions, the terms of the series for U , apart from the first, are of considerable importance and must be taken into account in estimating ζ from U .

scholarly journals DRIFT VELOCITY OF HOT ELECTRONS IN n-TYPE GERMANIUM

1962 ◽  
Vol 40 (9) ◽  
pp. 1056-1066 ◽  
Author(s):  
Robert Barrie ◽  
R. R. Burgess
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Drift Velocity ◽  
Applied Electric Field ◽  
Applied Field ◽  
Hot Electrons ◽  
High Fields

The drift velocity of electrons in n-type germanium has been measured as a function of applied electric field at lattice temperatures of 77° K and 295° K. Three directions of applied field were used, viz. (100), (110), and (111) crystal directions. The range of field strength was from 500 v/cm to 75 kv/cm. A longitudinal anisotropy was observed at 77° K but not at 295° K. All specimens showed saturation of the drift velocity at high fields. At 77° K, all (100) specimens exhibited a breakdown effect, the cause of which is not known. The results are analyzed on the basis of an extension of Stratton's theory to the case of a many-valley semiconductor.

scholarly journals The Changing Shape of a Liquid Drop in an Electric Field

2013 ◽  
Vol 3 ◽  
pp. 24-40
Author(s):  
A.A.S.N. Jayalal ◽  
K.A.I.L. Wijewardena Gamalath
Keyword(s):  
Surface Tension ◽  
Dielectric Constant ◽  
Aspect Ratio ◽  
Electric Field ◽  
Applied Electric Field ◽  
Applied Field ◽  
Cone Angle ◽  
Constant Ratio ◽  
Spherical Drop ◽  
Fluid Drop

An approximate extension of the slender body theory was used to determine the static shape of a conically ended dielectric fluid drop in an electric field. Using induced surface charge density, hydrostatic pressure and the surface tension of the liquid with interfacial tension stresses and Maxwell electric stresses, a governing equation was obtained for slender geometries for the equilibrium configuration and numerically solved for 3D. For an applied electric field, the electric energy on a spherical drop can be maximized in a weak dielectric by increasing the applied electric field. The minimum dielectric constant ratio needed to produce a conical end is 14.5 corresponding to a cone angle 31.25° .There is a sharp increment of the aspect ratio after reaching the threshold value of the applied field strength and the deformation of the fluid drop increases with the increase in dielectric constant of the fluid drop. For a particular dielectric constant ratio, the threshold electric field producing conical interface increases with the increased surface tension of the liquid. The threshold electric field for a water drop is 1.0854×104 units and the corresponding aspect ratio is 15. For the minimum dielectric ratio the cone angle of the drop decreases with applied field making the drop more stable at higher fields.

LIQUID CRYSTLASLIGHT SCATTERING BY FLUCTUATIONS INDUCED BY AN APPLIED ELECTRIC FIELD IN A NEMATIC LIQUID CRYSTAL (APAPA)

1972 ◽  
Vol 33 (C1) ◽  
pp. C1-63-C1-67 ◽  
Author(s):  
M. BERTOLOTTI ◽  
B. DAINO ◽  
P. Di PORTO ◽  
F. SCUDIERI ◽  
D. SETTE
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Nematic Liquid Crystal ◽  
Applied 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.

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