Bandwidth control

In the ABOs perovskites, bandwidth control may be accomplished by changing the ionic radius of the A-site (twelve-coordinate) cation. Essentially, this mimics the effect of pressure, which also effectively changes the B-O-B angle (see discussion in the... 

Speculate as to the nature of the M-NM transition. Does varying the chemical composition (the value of x) primarily result in filling control or bandwidth control ... 

The unit-cell volume expands with increasing lanthanum content. However, the metallic behavior appears with the larger unit cells. This is contradictory to bandwidth control, in which greater atomic orbital overlap would be expected to overcome correlation effects with contractions in the unit cell. 

The stractures of the alkali metal fullerides may be considered to be intercalation compounds of the fee lattice of the Ceo host formed by filhng the interstitial sites. Superconductivity has been investigated in detail for the alkali metal and mixed alkah metal phases of composition AgCeo where the conduction band is half filled. Critical temperatures as high as 31.3 K (in Rb2CsCeo) have been observed. A clear correlation between unit cell size and Tc is observed, and it has been suggested that the conduction bandwidth controlled by the separation between the molecules is the dominant factor in determining Tc. 

The section of Fig. 24 to the left is marked Polari2ation Control and is involved in electrical control of the cell potential or current. Note that the instrument can operate as either a potentiostat or galvanostat and the potential or current applied to the cell is programmed by summing the internal sources, marked DC Ref and Sweep, with an external polarity input. The box marked Feedback/Bandwidth control represents actual control circuitry similar to that in Figs. 8 and 11. Relays and electronic switches, controlled by the internal microprocessor, allow switching between potentiostatic or galvanostatic mode. Tbe microprocessor also sets the control loop bandwidth, which allows the experimenter to trade bandwidth for increased control loop stability. Other inputs to the feedback control circuitry are the RE potential and IR compensation (if necessary). A power amplifier is inserted at the counter (auxiliary) electrode connection. This allows currents of up to 2 A to be applied to the cell. 

For quantitative analysis, use a wavelength of maximum absorbance so that small errors in the wavelength do not change the absorbance very much. Choose a monochromator bandwidth (controlled by the exit slit width in Figure 19-5) small enough that it does not distort the band shape, but not so small that the spectrum is too noisy. Widening the slit width distorts the spectrum. In the lowest trace, a monochromator bandwidth that is one-fifth of the width of the sharp absorption bands (measured at half the peak height) prevents distortion. [Courtesy M. D. Seltzer, Michelson Laboratory, China Lake, CA.)... 

The application in-home network requires bandwidth control affected by the analyzed noises. The scenarios showed enough control with filters applied not at the noise source but at the electric connection in the data equipment. The neighbors electric networks are not expected to be affected by the noises in the PLC LAN but they could be affected by external noises even though their implications are filtered by the suggested appliances and it is not necessary to install special filters at the main electrical p>aneL... 

Bandwidth-controlled MI transitions, reflecting the divergence of the carrier effective mass m ... 

Katsufuji et al. used their results to estimate the critical value of the bandwidth-controlled Mott-Hubbard transition, (U/W)c 0.97, in the Ai-xCaxTiOs system. This value is below that estimated from quantum Monte Carlo simulations of the half-filled single band Hubbard model [72], (U/W)c 1.5 however a proper comparison between theory and experiment requires more careful consideration of both orbital degeneracy [149], which increases the critical value (U/W)c, and the deviation of the system from halffilling [150]. It is also worth noting for comparison that Ahn et al. estimate a value (U/W)c 2.7 from their measurements of the (Ca,Sr)Ru03 system [73]. 

One of the best examples of a bandwidth-controlled MI transition is that exhibited by the ANi03 series (A = rare earth). As shown in Fig. 7, the ANi03 compounds with A — Sm, Eu, Nd, Pr are Iow-Act metals with temperature-induced MI transitions ANi03 compounds with intermediate values of the tolerance factor (t), i.e., A = Sm, Eu, have MI transitions that are substantially... 

Inoue, I.H., Goto, O., Makino, H., Hussey, N.E., and Ishikawa, M. Bandwidth control in a perovskite-type 3d -correlated metal Cai cSr cV03.1. Evolution of the electronic properties and effective mass. Phys. Rev. B 1998, 58,4372—4383. 

Erkorkmaz K, Kamalzadeh A (2006) High bandwidth control of ball screw drives. Ann CIRP... 

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