Influence of pulse duration

Influence of pulse duration during machining of microtroughs by electrochemical micromachining [32]. 

Corona discharges have been investigated extensively for NO removal [38-54], The effect of electrodes configuration, electrical circuit, gas composition and flow rate were studied. When the discharge was operated in pulsed mode, the influence of pulse rise time, duration, and repetition frequency, as well as the effect of the voltage polarity on NO conversion, were considered by numerous authors. 

The influence of the duration of the second potential pulse t2 on the experimental RPV voltammograms corresponding to the catalytic process of Ti(IV) in the presence of hydroxylamine at an SMDE electrode can be seen in Fig. 4.24. These curves show the evident influence of t2 on the anodic currents owing to the presence of the catalytic process is evident. By using Eq. (4.224) by supposing that the chemical step is irreversible (i.e., K = 1 /Keq = 0), the value of the rate constant k = (1.90 0.05) s-1 has been reported [75]. 

In this chapter, we will review the effects of shock-wave deform.ation on material response after the completion of the shock cycle. The techniques and design parameters necessary to implement successful shock-recovery experiments in metallic and brittle solids will be discussed. The influence of shock parameters, including peak pressure and pulse duration, loading-rate effects, and the Bauschinger effect (in some shock-loaded materials) on postshock structure/property material behavior will be detailed. 

G.T. Gray III and P.S. Follansbee, Influence of Peak Pressure and Pulse Duration on the Substructure Development and Threshold Stress Measurements in Shock-loaded Copper, in Impact Loading and Dynamic Behavior of Materials (edited by C.Y. Chiem, H.-D. Kunze, and L.W. Meyer), Deutsche Gesellschaft fuer Metall-kunde, Germany, 1988, 541 pp. 

An important aspect of micromechanical evolution under conditions of shock-wave compression is the influence of shock-wave amplitude and pulse duration on residual strength. These effects are usually determined by shock-recovery experiments, a subject treated elsewhere in this book. Nevertheless, there are aspects of this subject that fit naturally into concepts associated with micromechanical constitutive behavior as discussed in this chapter. A brief discussion of shock-amplitude and pulse-duration hardening is presented here. 

Schneider et al. [63] investigated the photochemistry of the spiro-oxazine merocyanines pumping and probing at 570 nm in acetonitrile. The found that the solution bleached within the <5-psec pulse duration. The bleached state recovered with at least a biexponential behavior, and from their fluorescence decay measurements, three exponentials were required to fit the decay. They attribute these findings to the possibility of three merocyanine isomers that are in equilibrium. Their compounds feature geminal ethyl groups on the indoline moieties and this may influence the system as compared to NOSIl. 

Influence of Laser Bandwidth and Effective Pulse Duration on Nonlinear Signal Intensity, Showing the Dramatic Effect of Dispersion on Ultrashort Pulses... 

Stimulus pulse width may vary from 0.5 to 2.0 milliseconds. A recent study compared 0.5 msecond pulse width to 1.0 mseconds the shorter pulse width was found to be more efficient in inducing a seizure of adequate duration and less likely to result in a failed or an abortive seizure, and the associated peak heart rate was lower (Swartz and Manly, 2000). The authors also found that the pulse frequency (30 Hz vs. 60 Hz) did not influence the outcome. They concluded that a shorter pulse width was more efficient than a wider pulse width. Since data regarding pulse width are based on ETC in adults, until similar studies are conducted in adolescents, a shorter pulse width is preferable for adolescents. 

Figure 11. The Na+ fragment TOF spectra obtained with single long (chirped) pulses of 240 fs duration and 40-fs transform-limited laser pulses at 618 nm. The ratio of low energetic versus high energetic fragments is seen to be influenced by the pulse duration.

In Fig. 4.14, the influence of different parameters like the duration of the second potential pulse (t2, Fig. 4.14a), the heterogeneous rate constant (k°, Fig. 4.14b), and the electrode size (through rs, Fig. 4.14c) on the RPV responses of planar and spherical electrodes is shown. It is important to highlight that for irreversible processes the RPV curve presents two branches (cathodic and anodic), the null current plateau between them being wider the smaller k° is. 

In the variety of excitation or de-excitation processes that allow the preparation and/or observation of the system via the participation of the continuous spectrum, the dominant and most interesting characteristics are generated by the transient formation of nonstationary or unstable states. For example, the excitation may be caused by the absorption of one or of many photons during the interaction of an initial atomic or molecular state with pulses of long or of short duration. Or, the transient formation and influence on the observable quantity may occur during the course of electron-atom scattering or of chemical reactions. 

In order to avoid the influence of relaxation processes in the sample, the rate of the magnetic-field sweep in the studied interval should not be too high. So the field was generated in a solenoid with a large inductance, which provided a pulse duration of ss 15 10 3sec. 

Magunov AI, Pikuz TA, Skobelev IYu, Faenov AYa, Blasco F, Dorchies F, Caillaud T, Bonte C, Salin F, Stenz C, Loboda PA, Litvinenko IA, Popova VV, Baidin GV, Junkel-Vives GC, Abdallah Jr. J (2001) Influence of ultrashort laser pulse duration on the X-ray emission spectrum of plasma produced in cluster target. JETP Lett. 74 375-379... 

This being the case, the coherence among energy levels, hence the time dependence of the initial state, has no influence whatsoever on the product yield. This implies, for example, that in the weak-field regime, the product yield obtainable with a subfemtosecond laser pulse with frequency spectrum 1(a)) is exactly equal to the sum of a set of, for example, microsecond pulses with an appropriate set of frequen-cies and intensities that have the same cumulative I(co). Shorter pulses alter the. product probabilities only to the extent that they excite a larger number of states, as the frequency spectrum broadens with diminishing pulse duration. Clearly, am observation of increased yield of a particular product upon use of a shorter pulse is then due solely to the fact that the shorter pulse encountered some states with at preference for a particular product. ... 

The inverse of this frequency of rotation (27t/yB in seconds) is the time it takes for the sample magnetization to rotate one full cycle under the influence of the B field. This is simply the duration of a 360° pulse, and one fourth of this time is the 90° pulse duration, 190. 

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