Streak application

Application of the sample as a continuous streak is also possible using commercially available simple instruments (sample applicators), which give a sample zone for preparative separation less than 3 to 4 mm wide. It is also advisable to apply the streak across the plate starting 2 cm from both edges to avoid the edge effect, which may cause the motion of the mobile phase to be faster or slower at the edges than across the center of the plate. 

Of all these formulations, it is the diverse semisolids that stand out as being uniquely topical. Semisolid systems fulfill a special topical need as they cling to the surface of the skin to which they are applied, generally until being washed off or worn off. In contrast, fluid systems have poor substantivity and readily streak and run off the desired area. Similarly, powders have poor staying properties. Importantly, the fundamental physicochemical characteristics of solutions, liquid emulsions and suspensions, and powders are independent of their route of application, and are discussed adequately elsewhere in this text and need not be reconsidered. This is not to say the compositions of such systems cannot be uniquely topical, for there are chemicals that can be safely applied to the... 

If meridional streaks are found for materials built from layer stacks, these patterns can be analyzed analogously [259]. An application to data sets combined from series of reflections with increasing order is possible, as well. 

In this final section, we summarize the operation and characteristics of the principal vacuum tube and solid state detectors that are available for red/near-IR fluorescence studies. These include conventional photomultipliers, microchannel plate versions, streak cameras, and various types of photodiodes. Detector applicability to both steady-state and time-resolved studies will be considered. However, emphasis will be placed on photon counting capabilities as this provides the ultimate sensitivity in steady-state fluorescence measurements as well as permitting lifetime studies. 

The operation and application of streak cameras in fluorescence lifetime spectroscopy has been reviewed previously (see, e.g., Refs. 91 and 92). Streak cameras are useful in 2-D time-resolved imaging applications such as microscopy or multiwavelength array fluorometry. The operating principle is based on converting an optical pulse into a photoelectron pulse and spatially dispersing the electron image on a phosphor by means of a synchronized deflection voltage across two plates. 

For optical applications requiring extreme clarity it is desirable to minimize silver streaking, and yellowing. For example, Topas 5013 can be modified pentaerythritol tetrastearate, pentaerythritol distearate, or zinc stearate in order to improve the optical properties (59). These blends are suitable for high precision optical applications. 

Applications auto/truck windshield wiper fluid Notes Dries quickly, wipes clean, non streaking Formula T-113... 

By separating the coating from the substrate after deposition, the unique coating features of parylenes, especially continuity and thickness control and uniformity, can be imparted to a freestanding film. Applications include optical beam splitters, a window for a micrometeoroid detector, a detector cathode for an x-ray streak camera, and windows for x-ray proportional counters. 

Although many solvent developers are applicable to the acids and lactones, those containing acid have been favored. Acidic solvents, by a swamping effect, 129 suppress ionization of the sugar acids and thus prevent streaking of the acid spots.82 27 Otherwise, the ionized acids would be preferentially held by the stationary aqueous phase in the chromatogram, or would be adsorbed with resulting low RF values. In basic... 

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