Pulse transient

Here we describe the idea of active compensation of RF pulse transients.39 40 Even though the idea itself is simple, its practical aspect is somewhat complicated and tedious. In the following, we show how the home-built spectrometer and software can be flexibly adopted toward its implementation. 

The spectrometer supports phase cycling, asynchronous sequence implementation, and parameter-array experiments. Thus, most standard solid-state NMR experiments are feasible, including CPMAS, multiple-pulse H decoupling such as TPPM, 2D experiments, multiple-quantum NMR, and so on. In addition, the focus of development is on its extension of, or modification to, the hardware and/or the software, in the spirit of enabling the users to put their own new ideas into practice. In this paper, several examples of such have been described. They include the compact NMR and MRI systems, active compensation of RF pulse transients, implementation of a network analyzer, dynamic receiver-gain increment,31 and so on. 

Fig. 2.18. (a) The even (upper panel) and odd (lower panel) SH responses of a 20 nm Gd(0001) film at 90 K using 815nm/35fs laser pulses. Transient reflectivity change is also displayed in the upper panel (solid black curve). The inset shows the experimental scheme with the magnetization oriented perpendicular to the plane of incidence, (b) The oscillatory part of the even and odd SH fields extracted from (a). The inset shows the corresponding FT spectra. From [59]... 

Furthermore, pulse transient response experiments (129) show that the initial time at which CO was detected is shorter than that of C02 by about 0.2 s for a CH4/O2 (2/1) pulse at 773 K, in the presence of a reduced Ni/La203 catalyst. This result indicates that either the CO generation occurs earlier, or the CO desorption is faster than that of C02. However, the response curve to a pulse of pure CO and the response curve to a pulse of pure C02 were similar when a reduced Ni/La203 catalyst was used. Consequently, the delay of the C02 generation relative to that of CO is not caused by desorption, but by the earlier generation of CO. Therefore, the combination of experiments demonstrates that CO is the primary product. 

In Fig. 30.3, the thermodynamic efficiencies of a constant-pressure Bra3don cycle, a constant-volume Humphery cycle (which approximates a PDE cycle), and a true detonation Chapman-Jouguet (CJ) cycle for a typical hydrocarbon fuel are compared [11]. Though the constant-volume cycle shows substantial efficiency advantage, this zeroth order comparison cannot be taken as the correct quantitative comparison, since PDE operates in a pulsed transient mode. How-... 

Calvo, D., Duran, A., and del Valle, M. (2008). Use of pulse transient response as input information for an automated SIA electronic tongue. Sens. Actuators B 131(1), 77-84. 

Fig. 3 Spotting tools for non-contact printing a Bubble ink-jet A heating coil locally heats the loaded sample, resulting in a changed viscosity and expansion of fluids. The generated droplet can be easily expelled from delivery nozzles, b Microsolenoid A microsolenoid valve, fitted with the ink-jet nozzle is actuated by an electric pulse transiently opening the channel and dispenses a defined volume of the pressurized sample, c Piezo ink-jet A piezoelectric transducer that is fitted around a flexible capillary confers the piezoelectric effect based on deformation of a ceramic crystal by an electric pulse. An electric pulse to the transducer generates a transient pressure wave inside the capillary, resulting in expulsion of a small volume of sample...

Pulse transients using methane showed that methane decomposed over Pt giving gas phase hydrogen and leaving carbon on Pt. Subsequent admission of oxygen in pulses indicated that the carbon deposited by methane decomposition could be removed quantitatively by oxidation. Pulsing of carbon dioxide could also oxidize this carbon quantitatively and give gas phase CO. These reaction cycles could be repeated on the catalyst. 

The pulse residence time under vacuum conditions is much shorter than in conventional pulse experiments. Thus, a high time resolution is achievable. TAP pulse transients are capable of providing information about short-lived reaction intennediates, which are not detectable with a conventional step-transient technique. Therefore, transient experiments using TAP pulsing are valuable mostly for the detection and identification of reaction intermediates to formulate a reaction mechanism. 

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Analysis of the response gives the k values, as in the previous method. In this case, however, the preexponential factors are proportional to the Q values rather than the k values. The magnetic saturation recovery method has a distinct advantage over the pulse transient method in the frequently encountered case where one of the If values is very much smaller than the other. Very often, however, the Q values are more nearly comparable, and two exponentials can be detected in the saturation recovery method, even if both cannot be seen in the pulse (rapid-passage) transient method. 

Fig. 13. Single sweep displacement current records. Top superimposed membrane current records for 0.9 ms pulses from -110 to 20 mV (transient A during pulse, transient D after pulse) and to -240 mV (transient B during pulse, transient C after the pulse). Middle records shown in the upper part after subtraction of the linear capacitative and leakage currents (A+B and C + D). Fibre perfused with 300 mM CsF, 400 mM sucrose, 5 mM Tris-HCl at pH 7.3 in potassium and sodium-free saline at 6.5°C. Bottom summing A + D and B-l-C reveals the asymmetry in the transients A and D and the perfect linearity in the transients B and C.

Kinetics of pore nucleation on (100) p-type (0.05 cm) and n-type (1-4 cm) was observed as small steps in fast-current and potential pulse transients. 

This order applies to all varieties of reactors including, but not limited to light water moderated reactors, heavy water moderated reactors, liquid metal cooled reactors, gas cooled reactors and short-pulse transient reactors. Space reactor power and propulsion systems and critical facilities require special design criteria. Attachment 4 is reserved for Nuclear Safety Design for critical facilities and space reactors. 

Identification is provided by liquid phase chromatography (HPLC). Following the laser pulse transient electric conductivity can be measured. In view of the intensity dependence a 2-photon process is suggested with the wellknown benzene ion as the intermediate. The observed... 

In Figure 7.4a, we have displayed the probability of population transfer to vibrational levels in the Cs2 0 (65 + 6P3/2) excited state. During the pulse, many levels are populated, including highly nonresonant levels, due to time-energy uncertainty at short times. Rabi oscillations are visible diuing the pulse. Pulse transients are also observed, due to interferences between amplitudes of population coherently transferred to one level at different times they are discussed in Section 7.3.6. 

We have presented here the first observation of transient molecular reorientation induced in a liquid crystal by a -switched laser pulse. The response time of molecular reorientation in the nematic phase is of the order of 10—100 psec. Although this is 10 —10 times longer than the duration of the laser pulse, transient molecular reorientation is still strong enough to yield an easily detectable phase shift in the probe beam. Residual al> sorption and subsequent very rapid radiationless conversion into heat can result in a temperature rise in the medium which decays via heat diffusion with relaxation times in the 10—200 msec range. The temperature rise also induces a refractive-index change in the medium and hence a phase shift in the probe beam. This thermal effect and the molecular reorientation are initiated simultaneously by the pulsed laser excitation. They are in general coupled... 

Kouskov V, Sloop DJ, Liu SB, Lin TS. 1995. Pulsed transient nutation experiments on... 

Pump-probe experiments in the pico- and subpicosecond range were performed via tunable femtosecond pulses in the near infrared generated from an amplified continuum as described elsewhere [9,10]. The excitation energy was adjusted so that no more than 20% of the reaction centers were excited by each pump pulse. Transient absorption kinetics were recorded at a given wavelength using a two-diode system at the output slit of a spectrometer. 

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