Particle Trajectories in a Model Electric Field I,

1981 ◽  
Author(s):  
Yaakov Shima ◽  
Gabor Kalman ◽  
Paul Carini
Keyword(s):  
Electric Field ◽  
Particle Trajectories

Particle trajectories and its charging behaviors: effect of gas type and electric field

2020 ◽  
Vol 32 (10) ◽  
pp. 105702
Author(s):  
Jixing Sun ◽  
Qingyun Zhi ◽  
Boyuan Cui ◽  
Kai Bian ◽  
Weijiang Chen ◽  
...  
Keyword(s):  
Electric Field ◽  
Particle Trajectories

Dielectrophoresis of Nanoparticles

2004 ◽  
Author(s):  
Arun Thankamony John Kadaksham ◽  
Pushpendra Singh ◽  
Nadine Aubry
Keyword(s):  
Brownian Motion ◽  
Electric Field ◽  
Electric Fields ◽  
Numerical Scheme ◽  
Relative Magnitude ◽  
Hydrodynamic Forces ◽  
Uniform Electric Field ◽  
Particle Interactions ◽  
Particle Trajectories ◽  
Random Manner

A numerical scheme based on the distributed Lagrange multiplier method (DLM) is used to study the motion of nano sized particles of dielectric suspensions subjected to uniform and nonuniform electric fields. Particles are subjected to both electrostatic and hydrodynamic forces, as well as Brownian motion. The results of the simulations presented in this paper show that in the case of uniform electric fields the evolution of the particle structures depends on the ratio of electrostatic particle-particle interactions and Brownian forces. For solids fraction of the order 0.01, when this ratio is of the order of a hundred or more particles form stable chains and columns whereas when this ratio is of the order ten the particles are distributed in a random manner. For the non uniform electric field cases considered in this paper, the relative magnitude of Brownian forces is in the range such that it does not influence the eventual collection of particles by dielectrophoresis and the particular locations where the particles are collected. However, Brownian motion is observed to influence the transient particle trajectories. The deviation of the particle trajectories compared to those determined by the electrostatic and hydrodynamic forces alone is characterized by the ratio of Brownian and dielectrophoretic forces.

Particle Trajectories in a Model Electric Field II,

1981 ◽  
Author(s):  
Paul Carini ◽  
Gabor Kalman ◽  
Yaakov Shima
Keyword(s):  
Electric Field ◽  
Particle Trajectories

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).

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