Coupling currents

Dielectric constant/loss The value of the dielectric constant is important in the wire because of the effect that it has in coupling currents in one set of wires into another set of wires. The higher the dielectric constant, the higher the value capacitor that is formed between two wires. The capacitor thus formed is a signal carrying device at the frequencies used in communications and a signal can be capacitively coupled from one circuit to another. PE is the preferred choice for insulation of communication wire because of its low dielectric constant that minimizes the intercircuit coupling effect usually referred to as cross-talk. 

Time records of the coupling current and potential for the respective saii )les were obtained and stored for further analysis. 

Data is presented graphically to illustrate the variation in d.c. potential Figure 5) mean d.c. coupling current, i (Figure 6) and —j- (Figure 7) with time. 

Sisken, B. F. Lafferty, J. F. Pilla, A. A. The effects of inductively coupled current on sensory and sympathetic ganglia... 

Gaussian white noise is implemented according to the Box-Mueller algorithm [101]. Ic is the coupling current in network simulations which accounts for electrotonic gap-junction connections between the neurons. For bidirectional coupling of two neurons the coupling current Ic are of the form [94] ... 

For nearest neighbor coupling in bigger networks of, for example, ten by ten neurons the coupling current fc(i,j) of a neuron at position (i,j) is the sum of input currents from the neighboring neurons ... 

In all cases of electron transport, whether it be hopping, thermal emission, or quantum tunneling, the effect of the electric field in the oxide film is extremely important. In fact, the electric field effect on ion motion is the primary reason the electronic species must be considered at all in most real metal oxidation reactions. This can be understood better when we discuss the coupled-currents approach [10,11] in Sect. 1.15. 

We can think of the coupled-currents approach to metal oxidation in terms of the following logical sequence. 

As one example of a coupled-currents theory, the growth of very thick oxide films under local space-charge neutrality conditions will be considered in detail in the following section. 

The coupled-currents condition [eqn. (172)] for this case can be written as... 

Substituting the ionic current (species 1) and the electronic current (species 2) given by eqn. (96) into the coupled-currents condition gives the relation... 

This completes our development of the thick-film parabolic growth law. This particular theory has been presented in some detail because it is an extremely important domain of metal oxidation. In addition, it provides an excellent example of the way the coupled-currents approach [10,11] can be used to obtain oxide growth kinetics and built-in voltages in thermal oxidation. 

The pNZN electrons required for this reaction are provided by the electron current through layer N, which again is in accord with the coupled-currents condition for single-phase growth. This layer will have a decomposition rate as required for the formation of the new oxide in layer AT — 1, so in this respect it does not differ from the inner layers. However, this layer is not required to carry an additional cation interstitial current which subsequently flows into an adjacent layer, so in this respect it differs from the remaining layers. On the other hand, some oxides are volatile, or else they may decompose due to the presence of some agent in the ambient gas phase. In such cases, there is a loss which can be described in terms of the equivalent current Jj of cation interstitials required to... 

Assuming known values for the ph qh and R cv> and assuming a known evaporation rate for the oxide, we have a set of N equations for the growth rates dL,/dt of the N layers. This formulation for cation vacancy growth is general from the standpoint that no specific coupled-currents oxidation theory has yet been invoked to evaluate the currents J/cv) through the individual layers. 

The Qi Zj positive electron holes required for this reaction are provided by the electron-hole current through layer 1, again in accord with the coupled-currents condition for single-phase growth. 

Substrates Coupling Current Efficiency (%) Isolated yield of biaryl (%)... 

Statistical methods are the most popular techniques for EN analysis. The potential difference and coupling current signals are monitored with time. The signals are then treated as statistical fluctuations about a mean level. Amplitudes are calculated as the standard deviations root-mean-square (rms) of the variance according to (for the potential noise)... 

By taking the ratio of the standard deviation of the potential signal to that of the coupling current signal, a parameter with the units of resistance (or Q-cm2 when corrected for area) can be calculated. This ratio has been termed the noise resistance, Rn, by Eden and Rothwell (57) and has been found to correlate to the polarization resistance, Rp, to be discussed in Chapter 4. Localized corrosion indices have also been proposed (58), though none have been sufficiently correlated with other measurements to allow generalizations to be made. 

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