In-phase component

The power factor is the factor by which the apparent kva power is multiplied to obtain the actual power, kw, in an alternating current system. It is the ratio of the in-phase component of the line current to the total current. ... 

For collision frequencies large compared with the frequency of the electric field, the current remains in phase with the electric field in the reverse case, the current is 90° out of phase. The in-phase component of the current gives rise to an energy loss from the field (Joule heating loss) microscopically, this is seen to be due to the energy transferred from the electrons to the atoms upon collision. 

A noise power equivalent to one photon generates an interference signal which has an amplitude equals to twice the rms photon noise of the source. But as only the in-phase components of the source generates an interference with the local oscillator, the result is that the spectral Noise Equivalent Power of the heterodyne receiver is hv. 

The basic features of an epr spectrometer are shown in Figure 2.95. The microwave source is a Klystron tube that emits radiation of frequency determined by the voltage across the tube. Magnetic fields of 0.1 — 1 T can be routinely obtained without complicated equipment and are generated by an electromagnet. The field is usually modulated at a frequency of 100kHz and the corresponding in-phase component of the absorption monitored via a phase-sensitive lock-in detector. This minimises noise and enhances the sensitivity of the technique. It is responsible for the distinctive derivative nature of epr spectra. Thus, the spectrum is obtained as a plot of dA/dB vs. 

Figure 3.20 Profiles of p( V) (in-phase component) against electrode potential H for anodic and cathodic-going potential sweeps taken to 3 different anodic end potentials A = 0.86 V B =0.95 V and C = 1.12 V vs. RHE. showing progressive diminution of reversibility. Modulation frequency = 32.5Hz. amplitude = lOOmV peak-to-peak. The scan rate was SmVs 1. From...

This result, that the low frequency limit of the in phase component of the viscosity equates to the viscosity of the dashpot, means that for a single Maxwell model it is possible to replace rj by rj(0). Thus far we have concentrated on the description of experimental responses to the application of a strain. Similar constructions can be developed for the application of a stress. For example the application of an oscillating stress to a sample gives rise to an oscillating strain. We can define a complex compliance J which is the ratio of the strain to the stress. We will explore the relationship between different experiments and the resulting models in Section 4.6. 

Figure 3.20 Profiles of p V) (in-phase component) against electrode potential for anodic and cathodic-going potential sweeps taken to 3 different anodic end potentials A = 0 8fi V ...

It would seem reasonable to derive values for in-phase and out-of-phase moduli and tan 8 from the data generated. However, D945 specifies the calculation of the in-phase component of modulus and a number of other... 

In studying a system by a nonlinear impedance method, use is made of the system s nonlinear characteristics. A variant of the nonlinear impedance method called the amplitude demodulation method was first applied in the electrochemistry of semiconductors, in particular to diamond electrodes, in [83] (see the quoted paper for the theory of the method and the experimental set-up). A perturbing current signal of a high frequency oo, modulated in amplitude at a low frequency 2, is applied to electrochemical cell the demodulated low-frequency voltage signal is to be measured at the frequency 2. In accordance with the theory of the method [83], under the condition of formation of a depletion layer in a semiconductor electrode, the in-phase component of the cell response Re h is inversely proportional to d(C 2)/dE. Hence, for the acceptor concentration in the semiconductor we have [compare Eq. (1)] ... 

Table 1. Various lineshapes in the frequency and time domains. In the frequency domain g(f) corresponds to absorption mode lineshape and in the time domain G(t) corresponds to the in-phase component of the FID... 

A plot of Z and of —Z" vs. co 1/2 should give straight lines of slope o and of intercept Rct for the in-phase component (Fig. 11.5) corresponding to infinite frequency. The physical explanation for the intercept is that at very high frequencies the time scale is so short that diffusion cannot influence the current, being dependent only on the kinetics. If the lines obtained are not parallel then either the theory cannot be applied, or the experimental accuracy is bad. 

IMPS is a powerful technique for the study of photocurrent multiplication because it allows deconvolution of the minority and majority carrier contributions to the total photocurrent. The component of the photocurrent flux due to injection of majority carriers lags behind the in-phase component associated with the flux of photogenerated minority carriers. The time delay corresponds to the first order lifetime of the injecting intermediate, and the injection component is attenuated progressively as... 

As the tip position is modulated, the tip current alters accordingly. For a negative change in y (move closer to the substrate) the tip current increases over a conductor but decreases over an insulator with the two currents occurring 180° out of phase. By detecting the in-phase component of the modulated signal it is possible to identify exclusively the redox activity of the surface, with the added benefits of noise reduction (due to... 

The storage modulus (G ) is derived from the in-phase component of the stress while the loss modulus (G") is derived from the out-of-phase component. As stated above, the moduli depend on the phase angle obtained from the following relationships ... 

Look at this carefully it has an in-phase component (the term in sinot) and an out-of-phase component (the term in coscot). This can be used to define the relationship between stress and strain in terms of two moduli. First writing Equation 13-78 ... 

The in-phase component, G, is called the storage modulus while the out-of-phase component, G", is called the loss modulus. It also follows that (Equation 13-81) ... 

Figure 1. TICA temperature scan of the AT quinoxallne resin in (a) nitrogen environment and in (b) air. The in-phase component is labelled as curve a, and the out-of-phase component as b.

Figure 9.34 Frequency dependence of AC susceptibility at 0 and 2 kOe DC bias field for compound [NdCo(bpym)(H20)4(CN)6]-3H20. The filled symbols are for the in-phase component x f the open symbols are for the out-of-phase component %m" [68]. (Reprinted with permission from B. Ma, et al., Cyano-bridged 4f-3d coordination polymers with a unique two-dimensional topological architecture and unusual magnetic behavior, Angewandte Chemie International Edition, 2001, 40, 434 37 (Figure 3). Wiley-VCH Verlag GmbH Co. KGaA.)...

Figure 9 Magnetic-field dependence of the FM NMOR signals, showing quadrupole resonances at B = 143.0 fj,G, and the hexadecapole resonances at 71.5 /liG. Laser modulation frequency is 200 Hz, and modulation amplitudes is 40 MHz peak to peak the central frequency is tuned to the low-frequency slope of the F = 2 — F = 1 absorption line. Plots (a) and (b) show the in-phase component of the signal at two different light powers plot (c) shows the quadrature component. Note the increase in the relative size of the hexadecapole signals at the higher power. The insets show zooms on hexadecapole resonances.

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