Dispersion delay

Delay Due to Resistive Losses. On electrically long, lossy lines, the signal rise time is degraded by dispersion in the interconnection. Dispersion delays and attenuates the high-frequency components of the signal more than the low-frequency components because of the frequency-depen-dent resistance of the interconnection. The rise time degradation contributes additional delay before the switching threshold is reached at the end of the line. 

Calculation of CBF requires knowledge of the AIF, which in practice is estimated from a major artery, assuming that it represents the exact and only input to the tissue voxel of interest, with neither delay nor dispersion. There are several clinical situations, however, where the AIF TDC will lag, and the tissue TDC will lag behind the AIF curve ( delay ). AIF delay can be due to extracranial causes (atrial fibrillation, severe carotid stenosis, poor left ventricular ejection fraction) or to intracranial causes (proximal intracranial obstructive thrombus with poor collaterals). Moreover, in such cases, the contrast bolus forming the AIF can spread out over multiple pathways proximal to the tissue ROI ( dispersion ). Delay and dispersion can result in grossly underestimated CBF and overestimated MTT [125,147,148]. 

FIGURE 20 The pulse compression experiment of Grischkowsky et al., in which self-phase modulation and group velocity dispersion of a pulse in an optical fiber are balanced to produce a linear frequency chirp in the output pulse. The two passes off the diffraction grating constitute a dispersive delay time, which compresses this pulse to one-twelfth the width of the input pulse. [Reprinted with permission from Nikolaus, B., and Grischkowsky, D. (1983). Appl. Phys. Lett. 42, 1.]... 

Microchip platform (mostly into a monolithic piece) eliminates the necessity of most fluidic connections that otherwise link microfluidic components. Avoiding such connections greatly reduces sample dispersion, delay times, and dead volumes between different microchip compartments, and therefore, significantly increasing the separation power of such integrated miniaturized systems. 

The discovery of PTFE (1) in 1938 opened the commercial field of perfluoropolymers. Initial production of PTFE was directed toward the World War II effort, and commercial production was delayed by Du Pont until 1947. Commercial PTFE is manufactured by two different polymerization techniques that result in two different types of chemically identical polymer. Suspension polymerization produces a granular resin, and emulsion polymerization produces the coagulated dispersion that is often referred to as a fine powder or PTFE dispersion. 

If environmental and atmospheric conditions are such that vapor cloud dispersion can be expected to be very slow, the possibility of unconfined vapor cloud detonation should be considered if, in addition, a long ignition delay is likely. In that case, the full quantity of fuel mixed within detonable limits should be assumed for a fuel-air charge whose initial strength is maximum 10. 

Kurzendorfer [23] is of the opinion that in lime soap dispersions inversion does occur but that due to adsorption of LSDA on the surface of the lime soap micelle agglomeration is delayed, so that complete precipitation does not occur. 

The mass spectrometer sampling capillary or the dispersive infra-red analyzers used for continuous analysis and monitoring of the gas phase composition are situated between the reactor and the sampling valve, as close to the reactor as possible, in order to avoid any delay in the recording of changes in the composition of reactants or products. This delay should be taken into account when plotting simultaneously the time dependence of catalyst potential or current and gas phase concentration of the reactants or products. 

The optical delay results form the augmentation of the length of a dispersive material and the deformation of the optical waveguide. Con-... 

Simohamed, L.M., Reynaud, R, 1999, Characterization of the dispersion evolution in a large stroke optical fiber delay line. Optics Comm. 159, 118... 

Figure 3.10 Effect of different window functions (apodization functions) on the appearance of COSY plot (magnitude mode), (a) Sine-bell squared and (b) sine-bell. The spectrum is a portion of an unsymmetrized matrix of a H-COSY I.R experiment (400 MHz in CDCl, at 303 K) of vasicinone. (c) Shifted sine-bell squared with r/4. (d) Shifted sine-bell squared with w/8. (a) and (b) are virtually identical in the case of delayed COSY, whereas sine-bell squared multiplication gives noticeably better suppression of the stronger dispersion-mode components observed when no delay is used. A difference in the effective resolution in the two axes is apparent, with Fi having better resolution than F. The spectrum in (c) has a significant amount of dispersion-mode line shape.

P 68] No detailed experimental protocol was given [61, 62,142,143]. Two reactant streams, the solution of the reactant in hexane and concentrated sulfuric acid, were fed separately in a specially designed micro reactor by pumping action. There, a bilayer was formed initially, potentially decomposed to a dispersion, and led to rapid mass transfer between the phases. From this point, temperature was controlled by counter-flow heat exchange between the reaction channel and surrounding heat-transfer channel. The reaction was typically carried out at temperatures from 0 to 50 °C and using residence times of only a few seconds. If needed, a delay loop of... 

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