Pulsed-power applications types

Figure 1 Two-pulse or primary ESEEM data collected for the type-1 Cu(II) site of the Fet3p enzyme. Figure 1(a) shows the time domain data recorded under the following conditions microwave frequency, 9.6883 GHz field strength, 337.0 mT pulse power, 250 W 90° pulse length, 16 ns full width at half maximum (FWHM) sample temperature, 10 K. Figure 1(b) shows the ESEEM spectrum derived from the data of Figure 1(a) by subtraction of a biexponential decay function, application of a Hamming window function, and Fast Fourier Transformation (FFT). The absolute value spectrum is displayed...

Several composite pulse schemes as substitutes for 90° and 180° high power pulses have been proposed and in a similar manner to selective pulses, there is no composite pulse scheme that can not be used for any purpose. Table 5.18 categorizes composite pulses according to the nominal pulse angle, properties of the composite pulse and the type of pulse imperfection that must be minimized. Category A pulses can be used as an ideal pulse without any restriction. On the other hand the state of the magnetization before and after the pulse and the pulse imperfections which still arise despite the composite pulse determines the application for a category B pulse. 

Of the four modulation formats discussed, NRZ and URZ assume zero memory between pulses, and differentially encoded and spHt phase have memory imposed between pulses. Split phase has zero power density at / = 0 with the result that its bandwidth is double that of nonreturn-to-zero. In a sense, the zero power density at / = 0 is obtained in the case of split phase by imposing a particular type of memory between pulses. More general memory structures are used between pulses for applications such as magnetic recording. These can be classified as line codes. It is beyond the scope of this chapter to go into this subject here. A simple example is provided by assuming a square pulse function of width Ty for each bit, but with successive pulse multipliers related by at = Ay — Ay-i where At = 1 represent the bit value in signaling interval k. Thus the multiplier for puke k can assume the values 2 Ay = 1 and Aj i = —1), 0 (Ak = 1 and A/t i = 1), or —2 (A = —1 and A -i = 1). The power spectral density of this pulse modulation format can be shown to be (Ziemer and Tranter, 2002)... 

So far powerful lasers with picosecond to nanosecond pulse duration have usually been used for the ablation of material from a solid sample. The very first results from application of the lasers with femtosecond pulse duration were published only quite recently. The ablation thresholds vary within a pretty wide interval of laser fluences of 0.1-10 J cm , depending on the type of a sample, the wavelength of the laser, and the pulse duration. Different advanced laser systems have been tested for LA ... 

Plain-orifice atomizers are widely used for injecting liquids into a flow stream of air or gas. The injection may occur in a co-flow, a contra-flow, or a cross-flow stream. The best known application of plain-orifice atomizers is perhaps diesel injectors. This type of injectors is designed to provide a pulsed or intermittent supply of fuel to the combustion zone for each power stroke of the piston. As the air in the combustion zone is compressed by the piston to a high pressure, a very high pressure (83-103 MPa) is required to allow the fuel to penetrate into the combustion zone and disintegrate into a well-atomized spray. 

Some of the physical and chemical constraints on the flame atomization process — which usually precluded application to solid samples — were overcome with the advent of flameless atomization, initially accomplished with the pyrolytic coated graphite tube (or carbon rod-type) furnace atomizer. The graphite tube is a confined furnace chamber where pulsed vaporization and subsequent atomization of the sample is achieved by raising the temperature with a programmed sequence of electrical power. A dense population of ground state atoms is produced as a result for an extended interval in relation to the low atom density and short residence time of the flame. The earliest use of furnace devices in analytical atomic spectroscopy is credited to a simultaneous development by Lvov [15] and Massmann [16] however, the first application of one such device to a... 

Laser pyrolyzers are practically the only type of radiative heating pyrolyzer with certain applicability. Attempts were made in the past to use a strong light/heat source and focus the beam with lenses [20] to achieve the desired power output. However, the laser as a radiative energy source is much more convenient. The laser beam can be focused onto a small spot of a sample to deliver the radiative energy. This provides a special way to pyrolyze only a small portion of a sample. A variety of laser types were used for pyrolysis purposes normal pulsed, Q-switched, or continuous wave (cw) [21], at different energy levels. More common are the normal pulsed high-power lasers. 

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