A General Solution for the Displacements of Piezoelectric Media Which Are Subjected to Constant Electric Fields

A model is established to study needle domains in barium titanate single crystals using the theory of dislocations. Considering the mechanical and electrical compatibility in ferroelectrics, the fields produced by a needle domain are represented using the equivalent fields due to an effective edge dislocation coupled with a line charge. Accordingly, the dislocation fields derived by Barnett and Lothe for anisotropic piezoelectric media are used to analyze the stress and electric fields around needle domains. The interaction of the pairs of needle domains in an infinite piezoelectric body is studied by computing the interactive force and the total energy. It is found that the needle tip interactions tend to be dominated by the electrostatic terms. Additionally, comb-like arrays of needle domains are investigated. Stable configurations of needle domains in a herringbone pattern are identified, consistent with experimental evidence. However, comb-like arrays of needles are found to be unstable if perfectly insulating conditions without lattice friction are assumed.

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A general solution for the plane problem in piezoelectric media with collinear cracks

International Journal of Engineering Science ◽

10.1016/s0020-7225(98)00067-6 ◽

1999 ◽

Vol 37 (3) ◽

pp. 347-363 ◽

Cited By ~ 37

Author(s):

Cun-Fa Gao ◽

Wei-Xun Fan

Keyword(s):

General Solution ◽

Plane Problem ◽

Collinear Cracks ◽

Piezoelectric Media

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The Role of VLBI in the Establishment of Coordinate Systems

International Astronomical Union Colloquium ◽

10.1017/s0252921100051083 ◽

1975 ◽

Vol 26 ◽

pp. 293-295 ◽

Cited By ~ 1

Author(s):

I. Zhongolovitch

Keyword(s):

General Solution ◽

Future Development ◽

Rational Approach ◽

Radio Telescopes ◽

Coordinate Systems ◽

Tectonic Plates ◽

Astronomical Observations ◽

Optical Instruments ◽

Fundamental Polyhedron

Considering the future development and general solution of the problem under consideration and also the high precision attainable by astronomical observations, the following procedure may be the most rational approach:1. On the main tectonic plates of the Earth’s crust, powerful movable radio telescopes should be mounted at the same points where standard optical instruments are installed. There should be two stations separated by a distance of about 6 to 8000 kilometers on each plate. Thus, we obtain a fundamental polyhedron embracing the whole Earth with about 10 to 12 apexes, and with its sides represented by VLBI.

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Control of Metal Alloy Oxidation with Electric Fields

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071260 ◽

1973 ◽

Vol 31 ◽

pp. 164-165

Author(s):

R. R. Dils ◽

P. S. Follansbee

Keyword(s):

Electric Fields ◽

Oxidation Process ◽

Base Alloy ◽

Oxide Surface ◽

Platinum Electrodes ◽

Insulating Layer ◽

Iron Base Alloy ◽

Alloy Oxidation ◽

Aluminum Oxide Layer ◽

And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

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Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069387 ◽

1970 ◽

Vol 28 ◽

pp. 478-479

Author(s):

Teruo Someya ◽

Jinzo Kobayashi

Keyword(s):

Surface Layer ◽

Electric Fields ◽

Quantitative Study ◽

Recent Progress ◽

Ferroelectric Domain ◽

Resolving Power ◽

Surface Pattern ◽

Crystal Surfaces ◽

One Dimensional ◽

Ferroelectric Domains

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).

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