Stress singularity at the tip of a rigid conducting line in dielectrics under plane electric field

1995 ◽  
Vol 73 (2) ◽  
pp. R23-R26
Author(s):  
Shi Wei-Chen
Keyword(s):  
Electric Field ◽  
Stress Singularity ◽  
Conducting Line

Stress Analysis of Wiresaw Slicing Piezoelectric Materials

2000 ◽  
Author(s):  
Fuqian Yang
Keyword(s):  
Electric Field ◽  
Contact Mechanics ◽  
Mechanical Loading ◽  
Piezoelectric Materials ◽  
Electric Displacement ◽  
Stress Singularity ◽  
Potential Fields ◽  
Mechanical Interaction ◽  
Electric Loading ◽  
Linear Piezoelectricity

Abstract Using linear piezoelectricity theory, the stress and electric potential fields in a half infinite piezoelectric material under anti-plane mechanical loading in wiresaw slicing process has been studied by using appropriate boundary conditions and contact mechanics. Both electric field and electric displacement field are singular at the edges of the contact zone between wire and workpiece. The singularity of electric displacement arises from the electric loading and electro-mechanical interaction. Similar to the conventional contact mechanics, stress singularity occurs due to the contribution of both mechanical and electric loading. At a given mechanical loading, electric loading can either increase or decrease the stress applied to the piezoelectric half space in the slicing process, which depends on the relative direction of the electric field to that of mechanical loading.

Stresses Near the End of an Internal Electrode in Multilayer Electrostrictive Ceramic Actuators

1994 ◽  
Vol 360 ◽  
Author(s):  
Xiao-Yan Gong
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Electric Displacement ◽  
Electrical Coupling ◽  
Stress Singularity ◽  
Stress Difference ◽  
Finite Element Program ◽  
Coupling Problem ◽  
Internal Electrode ◽  
Element Program

AbstractStresses near the end of an internal electrode in a multilayer electrostrictive ceramic actuator are studied in detail. A finite element program capable of overcoming two major difficulties is developed. The program solves both the mechanical and electrical coupling problem and the nonlinear electric field and electric displacement relationship for these materials. Results indicate that the stress difference between the coupled and the uncoupled cases can only be distinguished when a stress singularity is present. Tensile stresses are found both in front, and behind, the end of an internal electrode. The magnitude of the stresses is predetermined by the material constants.

Resolution in photoelectron microscopy

1991 ◽  
Vol 49 ◽  
pp. 458-459
Author(s):  
G. F. Rempfer
Keyword(s):  
Electron Microscopy ◽  
Electric Field ◽  
Ultraviolet Light ◽  
Uniform Field ◽  
Virtual Image ◽  
Lens System ◽  
Photoemission Electron Microscopy ◽  
Planar Electrode ◽  
Electron Lens ◽  
Photoemission Electron

In photoelectron microscopy (PEM), also called photoemission electron microscopy (PEEM), the image is formed by electrons which have been liberated from the specimen by ultraviolet light. The electrons are accelerated by an electric field before being imaged by an electron lens system. The specimen is supported on a planar electrode (or the electrode itself may be the specimen), and the accelerating field is applied between the specimen, which serves as the cathode, and an anode. The accelerating field is essentially uniform except for microfields near the surface of the specimen and a diverging field near the anode aperture. The uniform field forms a virtual image of the specimen (virtual specimen) at unit lateral magnification, approximately twice as far from the anode as is the specimen. The diverging field at the anode aperture in turn forms a virtual image of the virtual specimen at magnification 2/3, at a distance from the anode of 4/3 the specimen distance. This demagnified virtual image is the object for the objective stage of the lens system.

Field-assisted ionization theory for microscopists

1994 ◽  
Vol 52 ◽  
pp. 820-821
Author(s):  
Patrick P. Camus
Keyword(s):  
Electric Field ◽  
Electron Tunneling ◽  
Ionization Probability ◽  
Critical Distance ◽  
Tunneling Probability ◽  
Field Ionization ◽  
Radius Of Curvature ◽  
Field Evaporation ◽  
A Value ◽  
Ion Emission

The theory of field ion emission is the study of electron tunneling probability enhanced by the application of a high electric field. At subnanometer distances and kilovolt potentials, the probability of tunneling of electrons increases markedly. Field ionization of gas atoms produce atomic resolution images of the surface of the specimen, while field evaporation of surface atoms sections the specimen. Details of emission theory may be found in monographs.Field ionization (FI) is the phenomena whereby an electric field assists in the ionization of gas atoms via tunneling. The tunneling probability is a maximum at a critical distance above the surface,xc, Fig. 1. Energy is required to ionize the gas atom at xc, I, but at a value reduced by the appliedelectric field, xcFe, while energy is recovered by placing the electron in the specimen, φ. The highest ionization probability occurs for those regions on the specimen that have the highest local electric field. Those atoms which protrude from the average surfacehave the smallest radius of curvature, the highest field and therefore produce the highest ionizationprobability and brightest spots on the imaging screen, Fig. 2. This technique is called field ion microscopy (FIM).

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
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