Compensation ratio

The multiloop controller contains a variety of func tion blocks (for example, PID, totalizer, lead/lag compensator, ratio control, alarm, sequencer, and Boolean) that can be soft-wired together to form complex control strategies. The multiloop controller, as part of a DCS, communicates with other controllers and man/machine interface (MMI) devices also on the DCS network. 

Fig. 3.47 Dependence of the compensation ratio 6 and free carrier concentration n ( = Nu on As source temperature, TXs, for GaAs crystals grown by the Bridgman method. ...

The carrier concentration n = Nt, — and the compensation ratio 6 which were obtained by measurements of the Hall coefficient and carrier mobility, respectively, were found to be functions of Fas or Pas- The compensation ratio 0 exhibits a minimum and the carrier concentration n a maximum, at the optimum temperature 617 °C, shown in Fig. 3.47. From the compensation ratio and the carrier concentration, the concentrations of the ionized donors, A, are calculated as a function of Tas, as shown in Fig. 3.48.At the optimum temperature 617 °C, Aq shows a maximum and Aa a minimum. The total concentration of ionized impurities, N, = N/ + N, remains essentially constant in the measured Tas range. This result suggests that vacancy-related mechanisms are associated with the formation of dislocations during growth and the compensation process. Thus, high quality crystal GaAs with a low density of dislocations has been grown by precise... 

Fig. 2.5. Temperature-dependent mobility of ZnO single crystals measured with the current flowing parallel (a) or perpendicular (b) to the c-axis of the crystals. The theoretical mobilities for the different scattering processes (optical, acoustical, and piezoelectric as well as ionized impurity scattering) as calculated by Wagner and Helbig [34,35] are shown as differently dashed lines. The calculated combined mobility curves (solid lines) fit the experimental data quite well for temperatures above about 20-50 K. The carrier concentrations at 300 K were about Ad — Na = 2.25 x 1016 cm 3 and Na = 2.75 x 1016 cm 3 (compensation ratio Aa/Ad = 0.55)...

FIGURE 1 Electron drift (solid lines) and Hall (broken lines) mobilities calculated for InN as a function of temperature. Left for n = 5 x 10 6 cm-3 and compensation ratios of zero (upper) and 0.60 right for n = 8 x 1016 cm 3 and compensation ratios zero (upper), 0.30, 0.60 and 0.75. Calculated curves from [6], experimental data from [9],... 

Fig. 6.47. Absorption between 1.2 and 11.2 meV of lightly-compensated n-type silicon samples due to electron hopping between D° and D+. The absorption is normalized by dividing by the compensation ratio K [166]. Copyright 1965 by the American Physical Society...

The spectral resolution and the fact that the compensation ratio of the sample used was 2 resulted in a superposition of lines 4 and 5 of Table 7.2, with ITe and 1T7 excited states, in peak 4 observed in this reference. 

The effect of the internal electric field on the line widths of the Ga acceptor lines has been studied as a function of compensation in isotopically controlled germanium samples with different 70Ge/74Ge ratios, where the Ga and As dopant was introduced by NTD [64]. The absorption of D (Ga) and C (Ga) lines for the same neutral Ga concentration No, but different compensation ratios K = Nas/Nqs, is shown in Fig. 8.39. 

In the preceding chapters and in the present one, values of the FWHMs of the EM electronic transitions have been considered, either as intrinsic characteristics of the transitions or in connection with the broadening mechanisms which depend on concentration, compensation ratio, or inhomogeneous impurity distribution. In Chaps. 6 and 7, examples of resonant broadening with lattice phonons, which depend on the difference between the phonons and electronic frequencies, have also been given and they are not considered here. The broadening due to the inhomogeneous Stark effect has been discussed in... 

The reader will have noted that any decrease in y/x toward 1 as y and x approach unity is neatly offset by the compensating ratio (1 - x)/(l - y). Thus, if y = 0.99 and x = 0.98, for example, a will still be considerably above unity. 

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