Localized multi-alternating-current modulation Kerr measurement of nonuniform three-dimensional electric fields

One of the electric-field measurement methods without intrusiveness uses the Kerr electro-optic effect. This method can be widely applied to gas, liquid, and solid materials, which are transparent and electrically birefringent. However, this method has not been adequately developed as yet for practical measurement of nonuniform three-dimensional electric fields. We describe a Kerr electro-optic measurement method for nonuniform three-dimensional dc and ac electric fields that employs localized multi-ac modulation, taking into account the effect of the observing (laser-beam) direction on the apparent electric field.     

Direct Observation of the Collection Process for Dust Particles from an Air Stream by a Charged Water Droplet

One of the most effective precipitation methods for submicrometer particles is the charged droplet scrubber. The dust collection in the charged droplet scrubber is considered to consist of some processes with respect to the interaction between charged dust particles and a charged water droplet. That is, the charged dust particles are attracted to, collide with, adhere to, penetrate into, rebound from, accumulate on, and reentrain from a charged water droplet. The direct observation of the collection process for dust particles by a charged water droplet was conducted by using the experimental setup designed by the authors. It was found from the experiments that particles with good wettability were captured inside the water droplet, particles with poor wettability floated at regular intervals on the droplet surface, and particles with medium wettability were trapped on or inside the water droplet. When particles were trapped on the droplet surface the growth of dendritic depositions was found, and their behavior was very distinct from those obtained on the fibrous filter due to the fluidity of the droplet surface. The deposition mechanisms of charged particles on the charged water droplet are discussed qualitatively.     

Three-Dimensional Model for Analyzing Charge Carrier Motion Around a Charged Spherical Object in the Presence of Flow and Electric Field

ABSTRACT

Generalized models in three dimensions are systematically developed reduced from the fundamental two-dimensional model for analyzing charge carrier motion around a charged spherical object with flow and electric field. As an example of its application in three dimensions, the collection efficiency in charged droplet scrubber is calculated. The purpose of this paper is to show a firm basis for work in this field specially by the generalized three-dimensional analyzing models and the corresponding tables.