Phase delay

Figure 1. Phase delay of Licrilite E202 cell, thickness 9.47)im, X 5l4nm. The solid line shows a power series best fit for the cell average data.

Figure 1. shows the measured phase differenee derived using equation (6). A close match between the three sets of data points can be seen. Small jumps in the phase delay at 5tt, 3tt and most noticeably at tt are the result of the mathematical analysis used. As the cell is rotated such that tlie optical axis of the crystal structure runs parallel to the angle of polarisation, the cell acts as a phase-only modulator, and the voltage induced refractive index change no longer provides rotation of polarisation. This is desirable as ultimately the device is to be introduced to an interferometer, and any differing polarisations induced in the beams of such a device results in lower intensity modulation. 

By using phase sensitive detection, the detector phase angle can be adjusted to be exactly out of phase with the phase-delayed emission from any single fluorophore, suppressing its contribution to the total emission signal. Phase sensitive detection, coupled with... 

One of us examined the timely use of three factors (melatonin treatment, exposure to light, physical exercise) to hasten the resynchronization of the sleep-wake cycle in a group of elite sports competitors after a transmeridian flight across 12 time zones (Cardinali et al. 2002). Outdoor light exposure and physical exercise were used to cover symmetrically the phase delay and the phase advance portions of the phase-response curve. Melatonin taken at local bedtime helped to resynchronize the circadian oscillator to the new time. Individual actograms taken from sleep log data showed that all subjects became synchronized in their sleep to the local time in 24-48 h, well in advance of what would be expected in the absence of any treatment (Cardinali et al. 2002). More recently, a retrospective analysis of the data obtained from 134 normal volunteers flying the Buenos Aires - Sydney transpolar route in the past 9 years was published this further supports such a role for exogenous melatonin in resynchronization of sleep cycles (Cardinal et al. 2006). 

In the last method, which is the most commonly used, the multiplier is replaced by an electronic switch controlled by the reference signal. The switch changes the amplification of the signal s(t) from +1 to —1 (for example +1 when the reference is positive and — 1 when it is negative), as shown in Fig. 10.10(a). When there is no phase delay between the... 

A SAW device is configured as a delay line and fed by a radio frequency signal. Any change in the velocity Av is detected as a change AT in the phase delay of the wave, thanks to a phase detector that gives a voltage proportional to the difference of phase between signal input and output. 

Practically, the phase delay and the modulation ratio mR of the light emitted by the scattering solution (solution of glycogen or suspension of colloidal silica) are measured with respect to the signal detected by the reference photomultiplier. Then, after rotation of the turret, the phase delay r/ F and the modulation ratio mF for the sample fluorescence are measured with respect to the signal detected by the reference photomultiplier. The absolute phase shift and modulation ratio of the sample are then — [Pg.179]

The data in Figure B11.1.1 were acquired with a frequency-domain FLIM instrument working in homodyne mode. In this mode, the modulation frequency of the intensifier (40 MHz) is identical to that of the excitation light (40 MHz). The phase and modulation are calculated from a series of images taken at different phase delays between the excitation light and the intensifier. 

The transient response of luminescent substances to modulated excitation can be determined in the frequency domain by measuring the phase delay and the demodulation of the luminescence with respect to the excitation. (14,23 28)... 

Similarly, the overall observable phase delay and modulation ratio can be obtained from Eqs. (9. 64) and (9.65). 

Frequency domain measurements require the use of periodic excitation sources. The luminescent molecules respond to the periodic excitation exhibiting the same frequency of modulation. This luminescence exhibits a phase delay and a demodulation with respect to the excitation due to the inability of the sensor molecule to respond to the higher frequencies of the excitation. This inability of the sensor molecules roughly begins at modulation frequencies /modulation of the same order of magnitude or faster than the decay rate... 

Each sinusoidally modulated light intensity of the response is phase delayed and demodulated with respect to the excitation such that... 

The phase delay and the modulation ratio can be determined at each harmonic available for measurement. These harmonics can range from a few hertz to several gigahertz depending on the harmonic content of the excitation and the lifetime of the luminescent molecule/14,25,27 28) Although all this information is available from the light signals, the instrumentation may limit the number of harmonics that can be measured. 

The phase delay A(nwE) and modulation ratio M(na>E) information of the high-frequency signals is transferred to low-frequency signals by amplitude modulation (cross-correlation) of r.(t) and Iff) with a periodic train of pulses C(f) given by Ref. 29. 

Fast Fourier transform algorithms are used to isolate the harmonics sampled. The individual phase delays are obtained from ... 

The linearity property of the Fourier transform does not hold for phase delay values. Let a, be the intrinsic, single measurement, time domain standard deviation of the filtered signal (in units of amplitude). Also let o>(n) be the standard deviation of the phase of the nth harmonic averaged j times. The phase noise as a function of harmonic (frequency) is given by... 

PHASES AND MODULATIONS of at the most Npl2 harmonics of the reference and the response are derived. From this absolute values the phase delay and modulation ratio of multiple harmonics are simultaneously obtained according to Eqs. (9.96) and (9.97), respectively. 

NUMBER OF RUNS Each ofthe Np/2 phase delay and modulation ratio values is memory averaged over several runs to complete the experiment. 

Initial insight of the role of CSN in cell-cycle control came from the finding that csnl and csn2 deletion S. pomhe strains have an S-phase delay [52]. Interestingly, this effect did not occur in strains missing other CSN subunits. The S-phase delay was caused by the accumulation of the cell-cycle inhibitor Spdl (S-phase delayed 1), which is involved in the misregulation of the ribonucleotide reductase (RNR). RNR catalyzes the production of deoxyribonucleotides for DNA synthesis and... 

Figure 21.10 shows the transient behavior of the combustor pressure as the proper phase-delay was applied at time t = 0 and the comparison of the pressure spectra. The high-amplitude oscillations were quickly brought under control and all of the harmonics, as well as the fundamental, were effectively suppressed in this case. The RMS pressure amplitude under active control was maintained well below 0.5% of the combustor pressure. It should also be noted, however, that oscillations at a very small level are still needed to maintain the phase-lock and vortex-synchronized fuel injection. 

The present study was conducted in an effort to better understand ACC mechanisms and to design practical ACC based on pulsed liquid-fuel injection suitable for propulsion devices. The controller utilized a simple fixed phase-delay approach that has been studied previously, but the direct liquid-fuel injection and the novel use of vortex-droplet interaction made the present study unique. The demonstration experiment in a 102-millimeter dump combustor showed that combustion instabilities can be successfully suppressed using properly designed pulsed liquid-fuel injection. 

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