High-voltage field

The mechanism for ozone generation is the exeitation and aeceleration of stray eleetrons within the high-voltage field. The alternating eurrent causes the electron to be attracted first to one electrode and then to the other. As the electrons attain sufficient velocity, they beeome capable of splitting some oxygen moleeules into free radical oxygen atoms. These atoms may then eombine with Oj moleeules to form O3. 

Atom probe techniques have been used to investigate adsorption processes and surface reactions on metals. The FIM specimen is first cleaned by the application of a high-voltage field evaporation pulse, and then exposed to the gas of interest. The progress of adsorption and surface reaction is monitored by the application of a second high-voltage desorption pulse and a controlled time delay. 

Electrical coalescers, in which a high voltage field is used to break down the stabilising film surrounding the suspended droplets, are used for desalting crude oils and for similar applications see Waterman (1965). 

Electrostatic precipitators devices used to trap fine dust particles (usually in the size range 30 to 60 p,m) that operate on the principle of imparting an electric charge to particles in an incoming airstream which are then collected on an oppositely charged plate across a high-voltage field. 

Klett and L. Nyholm, Separation high voltage field driven on-chip amperometric detection in capillary electrophoresis, Anal. Chem., 75... 

Klett O, Bjorefors F, Nyholm L (2001) Elimination of high-voltage field effects in end-column electrochemical detection in capillary electrophoresis by use of on-chip microband electrodes. Anal Chem 73 1909-1915... 

Thus we see that Coulomb forces increase the adhesion if the particles are precharged in electrostatic precipitators in separation processes (see Section 52), if powders are atomized in a high-voltage field (see Section 57), etc. In these cases, the electrical forces arising as a result of the charge on the particles will have a decisive influence on the adhesive interaction. 

Coulomb forces (image forces) are manifested when the particles are precharged under the influence of a high-voltage field. Under these conditions. Coulomb forces are greater than molecular forces and the electrical forces due to the contact potential difference, and the Coulomb forces will then determine the particle adhesion. These forces are governed by interaction of charged parti-... 

The detachment of particles may be prevented by sorption of ions on the surface. The charge acquired by a particle as a result of ion sorption (see Fig. VII. 2.c) should be determined by the residence time of the particle in the high-voltage field. According to experimental results reported in [130], particles acquire a maximum charge after being held in the field of a corona discharge for 0.1 sec, or in an electrostatic field for 5-10 min. 

According to this formula, for conductive particles with a diameter of 10 jum and = 20 V/cm, we find that Fqi = 1.5 10 dyn and for particles with a diameter of 100 jum and the same field strength, the force is 1.5 10 dyn. In this case, the forces of electrical interaction exceed the forces of particle adhesion (see Section 19) as measured without the effect on the high-voltage field. Particle detachment, however, is opposed not only by the forces of adhesion ad but also by Coulomb forces (image forces), the forces governed by the electrical double layer Fq with allowance for the charge on the particles in the electric field, and the ponderomotive force Fpon. 

The image force depends on the particle charge, which can be calculated for a conductive particle in a high-voltage field [199] ... 

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