Pulse timing

Fig, 5.15. A measured current-time pulse for shock-loaded Invar is shown. Time increases from left to right. The wave shape is closely predicted by the simple theory. Time from impact to peak current is about 1 fis. 

Curve fitting using a delta function for the pulse input for a TAP reactor should be limited to the latter % part of the response curve for curves of FWHM < 3 times pulse width, while for curves with FWHM > 4 times pulse width, it is a fair approximation fijr most of the curve. The assumption of a zero concentration at the reactor outlet is not good evrai for a pumping speed of 1,500 Is and broad response curves with FWHM > 1000 ms. 

A useful adjunct is the well-known pulse-chase technique, in which exposure to a radiolabeled compound for a specified period of time (pulse) is followed by the administration of the same compound that is not labeled (chase). 

Electronic demand limiting includes devices that monitor and measure the actual demand and provide control actions to limit the operation of attached devices when the measured demand reaches a specified value. These devices require two signals, the kilowatt hour (kWh) or demand pulse, which indicates the units of electrical energy consumed and a timing pulse, which indicates the end of one demand pulse and the start of the next one. 

Figure 1 Potential-time pulses in (a) linear sweep voltammetry (b) cyclic voltammetry. The slope of each line measures the potential scan rate...

Let us assume that only species Ox is initially present in solution, and that its movement to/from the electrode is governed by linear diffusion. If one starts from a potential value more positive than the formal potential E° of the redox couple Ox/Red and proceeds at a certain scan rate towards values more negative than E0/ (according to the potential-time pulse of the type illustrated in Figure la), a current-potential curve of the type shown in Figure 2 for the trace ABC is obtained. 

Figure 38 Potential-time pulses in Differential Pulse Voltammetry...

It is used in IC systems when the amperometric process confers selectivity to the determination of the analytes. The operative modes employed in the amperometric techniques for detection in flow systems include those at (1) constant potential, where the current is measured in continuous mode, (2) at pulsed potential with sampling of the current at dehned periods of time (pulsed amperometry, PAD), or (3) at pulsed potential with integration of the current at defined periods of time (integrated pulsed amperometry, IPAD). Amperometric techniques are successfully employed for the determination of carbohydrates, catecholamines, phenols, cyanide, iodide, amines, etc., even if, for optimal detection, it is often required to change the mobile-phase conditions. This is the case of the detection of biogenic amines separated by cation-exchange in acidic eluent and detected by IPAD at the Au electrode after the post-column addition of a pH modiher (NaOH) [262]. 

A much more positive value of E° = —0.88 V is estimated in aqueous solution at pH >11 by using short-time pulse techniques [7, 8], The aqueous electrochemistry of Tc04 is complex. Under alkahne conditions, it is proposed that the protonation of Tc04 and/or the expansion of its coordination shell follows Eq. (1) and produces a more easily reduced Tc(VI) species, resulting in a multielectron transfer [8]. The subsequent reduction can... 

This discovery was almost too good to be true. It meant that each PGO wave could serve not only as a timing pulse, but also as a unit of spatial information. Now we don t really know if PGO waves do either of these two important tasks, but synchronization of the brain by a pulse generator has to occur, as does the creation of internal models of the world. Before accepting these hypotheses as principles, we need to know whether humans also have a PGO system and what happens when that system is dissociated from the rest of the brain or disenabled. 

Aldehyde/ketone (5 mmol), amine (5 mmol), diethyl phosphite (5 mmol) and montmorillonite (1.5 g, Aldrich, montmorillonite, KSF) were admixed in a Pyrex test tube and exposed to microwave irradiation at 450 W using a (BPL, BMO, 700T, indicates the commercial name of microwave oven) focused microwave oven for an appropriate time (pulsed irradiation 1 min with 20 s interval). After complete conversion of the reaction, as indicated by TLC, the reaction mixture was directly charged on a small silica gel column and eluted with a mixture of ethyl acetate-hexane (3 7) to afford corresponding pure a-amino phosphonate. 

Couplings between nuclei influence the rate at which their characteristic frequencies diminish in the FID. If we could measure, in addition to the frequencies themselves, their rates of disappearance, we could determine which pairs of nuclei are coupled, because the signals of coupled pairs fade from the FID at the same rate. This is the basis of two-dimensional (2-D) NMR, which detects not only the chemical shifts of nuclei but also their couplings. The 2-D NMR employs computer controlled and timed pulses that allow experimenters to monitor the progress of relaxation for different sets of nuclei. 

This mixed influence can be observed from the expression of (Eqs. 3.68 and 3.69). In order to analyze the influence of the electrode size, Fig. 3.10a shows the current-potential curves obtained for a charge transfer process with different values of the dimensionless rate constant K°phe for a fixed/ 0 = 10-4 cm s 1 in NPV with a time pulse t = 0.1 s (i.e., for different values of the electrode radius ranging from 100 to 1 pm). As a limiting case useful for comparison, the current-potential... 

Although the usual way of analyzing the influence of the kinetics of the electron transfer on the SWV response is based on the variation of the frequency at fixed values of the staircase and square wave amplitude, a new approach for carrying out this analysis has been proposed based on the study of the influence of the square wave amplitude sw on the current potential curves at a fixed value of the frequency (or the time pulse) [19, 33, 34], The square wave amplitude has been used rarely as a tool in mechanistic and kinetic studies. One of the main reason is that, as stated in Sect. 7.1, in SWV the current is plotted versus an index potential which is an average potential between the forward and reverse potentials (see Eq. (7.7)) and leads to a discrepancy between the plotted and actual potentials at which the current is sampled. Therefore, the role played by Esw in the process is complex. 

The acceleration process begins with negative ion generation in the 300 kV injector followed by acceleration in the tandem at voltages up to 13 MV, The beam is bunched into timed pulses by passing it through a... 

Time-pulsing Mixing Most Relevant Citations... 

Time pulsing can be characterized by the Strouhal number (St), which is a dimensionless parameter describing the ratio of the flow characteristic time scale (L/V) to the pulse time period (1/j) [Eq. (1.8)] [26], where Lis the hydraulic diameter, V the average velocity in the outlet channel and/the pulsing frequency. For a pulsing frequency of 5 Hz, a Strouhal number of 0.375 derives. 

Another paper describes the stretching and folding of material lines yielded by simulation and experimental imaging, induced by time-pulsing mixing via unsteady cross-flow injection in a steady-flow main channel [48],... 

Mixer 83 [M 83] Time-pulsing Cross-flow Micro Mixer (I)... 

Mixer type Time pulsing cross- Channel width, 200 pm, 120 pm... 

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