Linear relation, between current and

Since the a.c. perturbation is small, the linearized relation between current and overpotential, rj (equation (6.50)), considering ara = arc = 0.5, may be used, that is... 

Linear Relation Between Current and Electrode Potential... 

Figure 6.1 Potential dependence of the partial current densities, Eqs. (6.8) and (6.9), and of the total current density (Eq. (6.11)). The dashed, straight line represents the region of linear relation between current and potential.

The interest of physicists in the conducting polymers, their properties and applications, has been focused on dry materials 93-94 Most of the discussions center on the conductivity of the polymers and the nature of the carriers. The current knowledge is not clear because the conducting polymers exhibit a number of metallic properties, i.e., temperature-independent behavior of a linear relation between thermopower and temperature, and a free carrier absorption typical of a metal. Nevertheless, the conductivity of these specimens is quite low (about 1 S cm"1), and increases when the temperature rises, as in semiconductors. However, polymers are not semiconductors because in inorganic semiconductors, the dopant substitutes for the host atomic sites. In conducting polymers, the dopants are not substitutional, they are part of a nonstoichiometric compound, the composition of which changes from zero up to 40-50% in... 

Thus, the recombination theory provided the first theoretical interpretation of the linear relation between polarization and the logarithm of current density that had been established experimentally. It is true, though, that the preexponential factor in Eq. (15.12) [2303(RTI2FI) 0.03 V] is four times smaller than the experimental values of slope b but it has been shown in later work that factors closer to the experimental values can be obtained when an inhomogeneous surface is assumed. 

The basic assumption In conductance measurements Is the Independence of the sample resistance on electric field strength. However a deviation from the linear relation between current density and field strength will be observed If any field effect on the mobility and/or the number of free charge-carriers Is present. 

With ohmic contacts, the current-voltage relation is often ohmic in nature up to a certain value and then becomes space-charge limited. This can be seen by a linear relation between current I (or current density j)... 

The solid circle of Figures 9(a)-(e) denotes the initial current levels I ini at various potential steps A , calculated from the corresponding CTs of Figures 2(a), 4, 7(a), 6(a), and 3(a), respectively. Undoubtedly, all the lini vs. AjB plots shows a linear relation. It should be mentioned that even the dijfusion controlled CTs can exhibit this type of linear relationship in the case where the electrode potential curves vary linearly with lithium stoichiometry, i.e. A oc (c - c However, the linear relation between lim and is still valid for the electrodes e.g. Lii+8[Tis/3Lii/3]04 Lii 5Co02 LigV205) where the electrode potential vs. lithium stoichiometry curves deviate strongly from the linear relationship. 

The linear relation between voltage and current density is not a result of the internal resistance of the fuel cell, being a purely ohmic resistance. Apart from the ohmic voltage drop across the electrolyte, kept in the pores of the matrix, a marked contribution to the voltage decrease comes from the polarization of the oxygen electrode. At a current density of 100 mA/cm, this amounts to 0.5 V. The polarization of the hydrogen electrode is considerably lower. 

The transformation between time and frequency domain requires linear and time invariant systems. Practically, linear refers to the relation between current and voltage within the... 

Eq. 5 was used [13] to interpret the nearly linear relation between 0 and p observed on platinized platinum in hydrochloric acid and hydrobromic acid solutions when the adsorbed hydrogen is removed at constant current (anodic charging curve). 

The realized experiments and the obtained results showed that measures by eddy currents present a linear relation between the evolution of the cementation thickness character and the impedance variation. 

From experimental measurements it was found that there was a fairly good linear relation between the SC capacitance and current, the slope being dependent on the electrode material and electrolyte. If the dependence is known, it can be used to make the Ragone plot calculations more accurate. Therefore, the following method was employed in our evaluations. 

In other words, the analysis of Iyer et al. differs from the analysis of Bockris et al. by predicting a linear relation between the steady-state hydrogen permeation current and (lobs - instead of iiQ. Figure 27... 

Receptor-mediated endocytosis may be possible because receptors have a high affinity for BDNF (Deckner et al. 1993). A linear relation between intranasal administration of -labeled NGF and brain concentrations of the compound suggest that this transportation is not mediated by receptors and that this releasing method of agents to the brain via olfactory nerves may be effective for many therapies (Frey et al. 1995). BDNF and the insulin-type growth factor (IGF-1) are currently used in clinical studies (Appel 1997). 

These measure the change in thermal conductivity of a gas due to variations in pressure—usually in the range 0.75 torr (100 N/m2) to 7.5 x 10"4 torr (0.1 N/m2). At low pressures the relation between pressure and thermal conductivity of a gas is linear and can be predicted from the kinetic theory of gases. A coiled wire filament is heated by a current and forms one arm of a Wheatstone bridge network (Fig. 6.21). Any increase in vacuum will reduce the conduction of heat away from the filament and thus the temperature of the filament will rise so altering its electrical resistance. Temperature variations in the filament are monitored by means of a thermocouple placed at the centre of the coil. A similar filament which is maintained at standard conditions is inserted in another arm of the bridge as a reference. This type of sensor is often termed a Pirani gauge. 

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