Duty-cycle efficiency

Finally one must also recognize that the duty cycle efficiencies of the two types of instrument are also different. The duty cycle efficiency, , is defined as the ratio of the time... 

In many contemporary interferometers, the duty cycle efficiency is improved by collecting data in both directions, or bidirectionally. In this case, interferograms are collected in both the forward and reverse directions. Of course, the speed... 

In practice, whether or not the spectra can be measured beneficially at high scan speeds is often determined by the duty-cycle efficiency of the interferometer, which is defined as... 

This problem can be illustrated by the data given in a paper by Hinsmann et al. [ 1], who used a Bruker Equinox 55 interferometer (see Figure 5.17) for stopped-flow measurements (see Section 19.2). The mirror velocity on this instrument was set so that data were acquired with a HeNe laser frequency of 280 kHz. For a spectral resolution of 32 cm , the time for each 1000-point interferogram was, therefore, 1024/ (280 X 10 ) s, or 3.66 ms. The time between successive spectra was reported as 45 ms, so that the duty-cycle efficiency was 8.1%. Clearly, the time resolution for this measurement was limited by the turnaround time and not the active scanning time. 

As seen in Section 4.1, the major types of losses are the conduction and switching losses. Conduction losses are addressed by selecting a better power switch or rectifier with a lower conduction voltage. The synchronous rectifier can be used to reduce the conduction loss of a rectifier, but it can only be used for forward-mode topologies, and excludes the discontinuous boost-mode converters. The synchronous rectifier will improve the efficiency of a power supply about one to six percent depending upon the average operating duty cycle of the supply. For further improvements, other techniques must be pursued. 

By the time-sharing principle, we see that in a Buck converter if Vsw is close to VD, the conduction losses do not change with duty cycle or input voltage. But the switching losses progressively increase, and so the efficiency falls off smoothly (almost linearly) with increasing input. See Figure 10-7 for the curve marked Vsw = VD. An example of this is the... 

Figure 12-5 The Three Fundamental Relationships Connecting Actual Duty Cycle and Efficiency...

Dotting the landscape of suburban North America, the family restaurant chain lies somewhere between the bistro and the fast food restaurant. Menus are longer, the food preparation is more complex, the kitchen has multi-purpose stations dedicated to types of food and sophisticated systems for communication and tracking. By streamlining the logistics of managing the overall process and improving the duty cycle of kitchen equipment, kitchen staff and kitchen space, these restaurants are able to efficiently offer the restaurant s most popular items and more rarely ordered novelties. The food quality is consistent, the response time is fair and the price is relatively low. 

These results are highly encouraging as they demonstrate the high power capability of the SiC RF-BJT devices along with acceptable power gain and efficiency. From thermal simulations, it is estimated that the junction temperature may reach a peak value of 171 C for pulse widths of 250 jus and 6% duty cycle without any external cooling. Since SiC junctions can easily sustain a temperature of 250 C, there is room to increase the pulse width even further. 

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