Saturation currents

Several areas of recent research activity that have an impact on rare earth usage in CRT phosphors have already been mentioned—pigmented phosphors for color TV, and voltage penetration and current saturable phosphors for two-color displays. 

In Fig. 4.3.3b we present a V — I curve with a turning point and a negative differential resistance region with current saturation, computed for the same values of parameters Ni, A, cq as in Fig. 4.3.3a. This V—I curve corresponds to the upper and the middle solution branches. The range of parameters in which the high current solutions exist is again evaluated below, via an asymptotic treatment for /— oo. 

The conditions in terms of N4 for the occurrence of the steady state multiplicity can be summarized as follows. According to (4.3.17b), for co 1, there exists a low current branch with current saturation as long as the following condition holds ... 

It is easily checked that for F, F given by (4.3.33a)-(4.3.45), with the accuracy employed in our computations, conditions of the Newton-Kantorovitch theorem are satisfied, unless we are in an extremely close vicinity of the lower and middle limiting currents. Indeed, even for the stiff example of Fig. 4.3.4 (well within the range of current saturation at the lower and middle branches) with the accuracy employed, we have from (4.3.33)-(4.3.45) the data shown in Table 4.3.1. 

Effects of space charges (finite e). It is expected that the inclusion of space charges will eliminate current saturation (limiting currents) at the lower and middle branches. These branches are instead expected to meet at another turning point, due to punch through (in this purely electro-diffusional formulation without source terms).5... 

Dean K.A., Chalamala B.R. (2000) Current saturation mechanisms in carbon nanotube field emitters. Appl. Phys. Lett. 76 375-7. 

In forward bias (positive V ) the current increases exponentially with (when kT) and in reverse bias the current saturates at J. The forward bias current is more usually written as... 

Annual production of caustic soda (sodium hydroxide) in the United States is about 10 million metric tons, of which 50% is consumed by the chemical industry and a further 20% by pulp and paper plants. Sodium hydroxide is made by electrolyzing strong brine, that is, decomposing it by passing an electric current. " Saturated brine contains about 360 g or 6.2 mol NaCl per kilogram water. 

SCH] Schumb, W. C., The dissociation pressures of certain salt hydrates by the gas-current saturation method, J. Am. Chem. Soc., 45, (1923), 342-354. Cited on pages 269, 328. 

The resulting output characteristic for Pt and Rh nanoisland catalysts (Figure 2.102) shows a rather sluggish increase of the cathodic photocurrent, indicative of surface recombination, and, at the potential of the hydrogen redox couple, current saturation has not yet been reached. Even at 0.2V cathodic from Er,o (H2/H ), where band bending is increased, carrier collection does not yet reach a saturation value. The low observed efficiencies are attributed to pronounced surface/interface recombination and to the reduced contact potential difference between p-Si and... 

Measurements of current-voltage characteristics (CVCs) of the above-mentioned structures were carried out at room temperature in air and in mixtures of air with different concentrations of carbon monoxide. The typical CVCs of samples with a porosity of 73% in all environments have a nonlinear behavior. The CVC is nonlinear for low back bias, but becomes linear with an increase in low back bias. The CVCs for PSi of 73% porosity, both in air and in air + 0.4% CO, have rectifying characteristics, but, as compared with the corresponding characteristics of samples with 50%-PSi, a sharp decrease in conductivity and an absence of current saturation took place. The factor of ideality m was estimated from the initial part of the direct branch. The barrier height was determined from the linear part of the backward branch of the CVC. 

The anisotropic continuum approach to losses in multifilament conductors was first conceived by Carr, who developed the model assuming that the inductor is a continuum material with anisotropic resistivity. He applied this approach to the special case of losses in cylindrical conductors for applied transverse sinusoidal fields in the absence of transport current [ ]. Those losses resulting from pJ in the conductor are classified as eddy current or saturation hysteresis losses, depending upon the level of /. Eddy current losses result from J below Jc, with the implicit assumption of rapidly rising resistivity in the flux-flow regime with currents saturated at Jc. The magnetization loss for the continuum is essentially the magnetic hysteresis loss for the filaments times the fraction of the composite occupied by the filaments. 

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