Phase shift reduction

Figure 4-275b is a schematic of the operating principle. Two signals are measured the wave amplitude reduction and the wave phase shift. 

Hellstrand That is what I am getting at. There are a lot of phase shifts in this system. One observation we have made is that under hypoxia we see a decrease in amplitude but an increase in frequency of the waves. We are trying to model a case where this would account for reduction of force simply on the basis of non-linearity of the [Ca2+] versus myosin phosphorylation versus force reactions. It seems intuitively that this could explain why there can be a reduction in force although there is no reduction in the overall level of global Ca2+. Is amplitude modulation something that people have seen ... 

Figure 9.5 EXAFS of Rh/AKO, catalysts after reduction at 200 °C (left) and 400 °C (right) top the magnitude of the Fourier transform of the measured EXAFS signal, bottom the back transformed EXAFS corresponding to distances from Rh atoms of between 0.8 and 3.2 nm. The lower Fourier transform contains a dominant contribution from Rh nearest neighbors at 0.27 nm and a minor contribution from oxygen neighbors in the metal-support interface. After correction for the Rh-O phase shift, the oxygen ions are at a distance of 0.27 nm (from Koningsberger et at. 119]).

The results obtained with the model for the mammalian circadian clock provide cues for circadian-rhythm-related sleep disorders in humans [117]. Thus permanent phase shifts in LD conditions could account for (a) the familial advanced sleep phase syndrome (FASPS) associated with PER hypopho-sphorylation [118, 119] and (b) the delayed sleep phase syndrome, which is also related to PER [120]. People affected by FASPS fall asleep around 7 30 p.m. and awake around 4 30 a.m. The duration of sleep is thus normal, but the phase is advanced by several hours. Moreover, the autonomous period measured for circadian rhythms in constant conditions is shorter [121]. The model shows that a decrease in the activity of the kinase responsible for PER phosphorylation is indeed accompanied by a reduction of the circadian period in continuous darkness and by a phase advance upon entrainment of the rhythm by the LD cycle [114]. 

Once a set of initial phases has been chosen, it must be refined against the set of structure invariants whose values are presumed to be known. So far, two optimization methods (tangent refinement and parameter-shift reduction of the minimal frmction) have proven useful for extracting phase information from the structure invariants. The tangent formula (Karle and Hauptman, 1956),... 

Hence, a reduction in volume will cause the phase shift to decrease as shown in Fig. 6.10. This decrease in a3 causes the long-range oscillations to move out with respect to the nearest neighbour positions in Fig. 6.7 and Fig. 6.9, thereby causing a possible change in the relative stability of different competing metallic structure types. 

We have implemented the discrimination in the frequency domain. As is known in multifrequency phase fluorometry,17 the time-delayed fluorescence acquires a phase shift >p and a reduction in amplitude Mp upon increasing the modulation frequency m = 2irf of the sinusoidally modulated excitation. For a simple single exponential decay, this phase shift

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For preparations on high area support reduction does not show a significant shift in peak position, consistent with the expected enhanced difficulty to reduce the oxide, which is tightly bonded to the substrate. Indeed, increased Sn loading tends to shift the first peak to lower R values. The second peak in the reduced preparations may be assigned to an overlap of (Pt-Pt) and (Pt-Sn) interactions. Unfortunately, these critical distances are too close to be resolved. The phase shift corrected distance for Pt-Pt in metal is 2.77 A, whereas and Pt-Sn are 2.62 A and 2.83 A in PtSn and PtjSn, respectively. By itself the presence of this peak does not prove the existence of an alloy because dried and calcined samples (at the Sn K edge) also show a strong peak at 2.5 A. A variety of solid solutions of the... 

An oscillatory cycle can be qualitatively described in the following way. Suppose that a high enough ceric ion concentration is present in the system. Then, bromide ion will be produced rapidly, and its concentration will also be high. As a result, autocatalytic oxidation is completely inhibited, and the ceric ion concentration decreases owing to the reduction of ceric ion by malonic acid. The bromide ion concentration decreases along with that of ceric ion. When the ceric ion concentration reaches its lower threshold, the bromide ion concentration drops abruptly. The rapid autocatalytic oxidation starts and raises the ceric ion concentration. When this concentration reaches its upper threshold, the bromide concentration increases sharply, completely inhibiting the autocatalytic oxidation. The cycle then repeats. Pulse injections of Br, Ag, and Ce " result in phase shifts in oscillations of the Ce " " concentration (Fig. 3), which confirm the mechanism. 

Figure 15.6 Phase shift of the EHD impedance corresponding to the ferricyanide reduction on a platinum electrode (area 0.38 cm ) coated with a photoresist on which an array of circular sites of diameter dact was patterned, dact = 649 fim, Ci — 96 rpm ( ) and 375 rpm (A). Theoretical curve for a single microelectrode (dashed line), or for the active disk electrode (solid line). (Taken from Deslouis and Tribollet. )...

Fig. 7. Pt—Re on alumina catalysts at the reduced step compared to the metal. Radial distribution functions (uncorrected from phase shifts) at the Lj edges of Pt and Re for two reduction temperatures...

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