LAPS technique

Complex formation occurs in MeN02 solution and the solution is then applied to the surface to be coated. Washing with water removes the Lewis acid leaving a thin film of the photosensitive pigment. The Lewis acid pigment solubilization (LAPS) technique has been used to fabricate multilayer photoconductors and appears to have a promising technological future. 

Defects such as hot tears or laps, quench cracks, localized overheating during stress rehef, and corrosion may occur during the tubemaking process (154). Magnetic particle, ultrasonic, and visual inspection techniques are used to ensure that relatively few tubes enter service with significant defects. 

Diffusivities of various elements ate determined experimentally. Dopant profiles can be determined. The junction depth can be measured by chemically staining an angle-lapped sample with an HE/HNO mixture. The -type region of the junction stains darker than the n-ty e region. The sheet resistivity can also be measured using a four-point probe measurement. These two techniques ate used for process monitoring. 

Leung. Tobacco cigarette smoke attenuates duodenal ulcer margin hyperemia in the rat. Comparison of lAP clearance and hydrogen gas clearance techniques for measurements of gastrointestinal blood flow. Dig Dis Sci 1995 40(5) 1112-1117. 

Substrates are prepared for film deposition from the crystals by sawing, lapping and polishing using techniques similar to those used in the semiconductor industry. 

To prevent contamination aseptic technique should be strictly applied during handling of agar strips all handling should be under LAP. 

Besides the traditional capacitance versus voltage (C/V) measurements, which are mainly used for the characterisation of MOS and EIS capacitances, the scanned light pulse technique (SLPT) was introduced by Engstrom and Aim [13], first for MOS structures. This technique utilises a fight source to illuminate a local area of the MOS structure. Thus, a local photo-effect-induced current can be measured, which only depends on the local properties and energy states of the illuminated region of the MOS structure. In 1988, Hafeman et al. combined this SLPT method with EIS structures to develop the LAPS [14,15]. This sensor is capable of measuring the surface potential of the electrolyte-transducer interface with a lateral resolution. Hence, the surface... 

Engstrom and Carlsson already introduced in 1983 an SLPT [119] for the characterisation of MIS structures, which was extended to chemical gas sensors by Lundstrom et al. [26]. Both SLPT and LAPS base upon the same technique and principle. However, due to the different fields of applications in history, one refers to LAPS for chemical sensors in electrolyte solutions and for biosensors, and the SLPT for gas sensors. A description of the development of a hydrogen sensor based on catalytic field-effect devices including the SLP technique can be found, e.g., in Refs. [120,121]. The SPLT consists of a metal surface as sensitive material which is heated by, for instance, underlying resistive heaters to a specific working-point temperature, and a prober tip replaces the reference electrode (see Fig. 5.10). 

Fig. 5.10. Principal set-up of the scanning light pulse technique for gas-sensing LAPS.

LAPS was introduced by Sato et al. [155]. The detection of heavy metal ions by thin films of chalcogenide-glass membranes using the pulsed laser deposition method (PLD) was reported by Mourzina et al. [156]. The PLD technique was also introduced to evaporate A1203 as a pH-sensitive material for LAPS devices [157]. The first practical application of the above-described LAPS card was demonstrated by Kloock et al. for a comparative study of Cd-sensitive chalcogenide glasses for ISFETs, LAPS and pISEs (ion-selective electrodes) [158]. 

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