Lime-domain

Figure 15.7 (b) Comparison of the photoinduced absorption spectra for near steady stale (millisecond) and ultrafast (picosecond) lime domains for P30T/C composite films. The picosecond photoinduced spectra arc taken at 300 K at various delay limes after a 2.01 eV 100 Is pump pulse for P3OT and P30T/C,., (reproduced by permission of World Scientific from Ref. I7 ). 

Pyroelectric transducers exhibit response limes thal are fast enough to allow them lo track the changes in the lime-domain signal from an interferometer. For Ihis reason, most Fourier transform infrared spectrometers use this type of transducer. 

The plots in Figure 7-41c and d are conventional spectra of two monochromatic sources with frequencies j/j and IN [ /.. The curve in Figure 7-4le is the spectrum of a source that contains both frequencies, in each case, the radiant power P(i ) is plotted with respect lo Ihe frequency in hcrlz. The symbol in parentheses is added to emphasize the frequency dependence of the power lime-domain power is indicated by f t). 

Figure 7-42 is a lime-domain signal from a source that contains many wavelengths. It is considerably more complex than those shown in Figure 7-41. Because a large number of wavelengths arc involved, a full cycle is not completed in the time period shown. A pailcrii of beats appears as certain wavelengths pass in and out of phase. In general, the signal power de-...

It is important to appreciate that a lime-domain signal contains the same information as a spectrum does in the frequency domain, and in fact, one can be... 

TTic inierconversion of lime- and frequency-domain signals is complex and mathcmatfcally ledious when more Ilian a few lines are involved the operation is only practical with a computer.Today fast Fourier Iransform algorithms allow calculation of frequency-domain spectra from lime-domain spectra in seconds or less. 

It is possible to show that to resolve two lines, Ihe lime-domain signal must be scanned long enough so that one complete cycle, or beat, for Ihe two lines is... 

Tvvo vidcl used approaches are used for lifetime measurcnienis. ilie lime-domain approach and the frt i/iu niy-domain approach. In tinte-domain measurements. a pulsed source is employed and the time-depcndcnr decay of fluorescence is measured. In the frequency-domain method, a sinusoidallv modulated source is used to excite the sample. The phase shift and demodulation of the fluorescence emission relative lo the excitation waveform provide the lifetime information. ( onimercial instrumentation is available to implement both techniques. ... 

H. Fordedal, 0. Midttun. J. Sjdblom, O. M. Kvlheim, Y. Schildberg, J. L. Vollei. A multivariate screening analysis of W/O emulsions in high external electric fields as studied by means of dielectric lime domain spectroscopy. I). Model emulsions. stabilized by interfacially active fractions from crude oils. J. Collord Interface Sci. 182 117-125, 1996. 

Irrespective of whether the donor intensity decays are measured in the lime domain or the fiequenqr domaiii, the infonnalioo content of the time-iesolved data is limiled. It is not possible to detennine a distance iSstribution of arbitrary shape. For this reason, it is common practice to describe the distribution nsingalimited number ofparame-... 

The modes of encoding information as electrical quantities can be subdivided into analog domains, lime domains, and the digital domain, as illustrated in the bottom half of the circular map in Figure 1-2. Note that the digital domain is not only composed of electrical signals but also includes one nonelectrical representation, because numbers presented on any type of display convey digital information. 

S. Tanev et al. / The Finite-Difference lime-Domain Method in the Biosciences... 

Khazan, M.A. (2002) lime Domain Terahertz Spectroscopy and its Application to the Study of High Tc Superconductor Thin Films, Doctoral Thesis, University of Hamburg. 

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