CCD systems

Figure 43. Simplified flow scheme for a three-stage CCD system.

Because of the double exposure, the preparation suffers from increased bleaching and photodamage. Furthermore, split-imaging on charge-coupled-device (CCD) systems (see Textbox 1) is not an option. Nevertheless, excitation ratioing may be an economic choice for laboratories that have an old Fura-imaging setup. These microscopes often allow very fast excitation switching... 

Number of Channels, Nc- For CCD systems, Nc is usually the number of pixels (short for picture elements ) along the wavelength axis. Nc is not necessarily equal to the number of resolution elements (Vr) discussed in Chapters 3 and 4. 

Even with this reduced SNR, there are many samples where fluorescence is too large to permit useful SNR with CCD/dispersive systems. Figure 9.8 shows the case of a polymer composite for which a useful spectrum was acquired with 1064 nm excitation and FT-Raman, while a dispersive/CCD system operating at 514.5 or 785 nm yielded mainly (or entirely) broadband fluorescence. 

A further advantage of a multi-CCD system is the linear dispersion and the onedimensional spectral dispersion. This both facilitates comparison of recorded and saved spectra and enables a high radiation throughput as the whole height of the... 

In-situ luminescence measurements have been used to study the semiconductor/ electrolyte interface for many years (e.g. Petermann et al., 1972). Luminescence may result from optical excitation of electron/hole pairs that subsequently combine with the emission of light (photoluminescence). Alternatively, minority carriers injected from redox species in the electrolyte can recombine with majority carriers and give rise to electroluminescence. The review by Kelly et al. (1999) summarises the main features of photoluminescence (PL) and electroluminescence (EL) at semiconductor electrodes. The experimental arrangements for luminescence measurements are relatively straightforward. Suitable detectors include a silicon photodiode placed close to the sample, a conventional photomultiplier or a cooled charge-coupled silicon detector (CCD). The CCD system is used with a grating spectrograph to obtain luminescence spectra. 

We performed the experiments on a static water sixrface contained in a rectangular glass vessel of dimensions 25 cm x 10 cm x 10 cm, as shown in Fig. 1. A real or artihcial leg was stuck to a manipulahon device which was driven manually by a screw micrometer device with a displacement accuracy of 0.01 mm. Once the leg contacted the water surface, it was controlled, very slowly and carefully, to tread downwards into the water surface for 0.05 to 0.2 mm in each step. The side views of the shapes of the leg and the trodden water puddles at different treading angles and displacements were recorded by a CCD system. 

Figure 1. Experimental system including screw micrometer device, manipulation device, rectangular glass vessel and CCD system.

Prior to the much-vaunted renaissance of the Raman technique with the advent of FT instrumentation or the availability of CCD systems, there were few literature reports on the use of Raman spectroscopy for investigating pharmaceutical systems. The technique has been used to characterize drugs in much the same way that infrared has been used for identification testing. Thus, the infrared (IR) and Raman spectra of Dapsone, used in the treatment of leprosy, have been reported [1]. 

CCL), and finally one solves the full nonlinear CCD system. The CCD problem can be solved routinely on a CYBER-845 computer up to about 30,000 excitations with the program in Erlangen. 

The surface morphology of the SMPU fibers was studied by a Leica Stereoscan 440 SEM. A single fiber of the produced multi-filament SMPU fibers was attached to the SEM sample holder. The accelerated voltage of the electron beam was 20 kV and the secondary electron images were recorded by the CCD system in the SEM. 

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