Profile modification technique

An important aspect concerning catalytically active membrane reactors, is the distribution of the active phase within the membrane system. Modem modification techniques (van Praag et al. 1989, Lin, de Vries and Burggraaf 1989) allow control over the catalyst distribution and preferential deposition of the active phase at different places in the membrane (top layer/support) system. Studies on conventionally used plate-shaped and cylindrically-sha-ped catalytically active pellets (Vayenas and Pavlou 1987a, b, Dougherty and Verykios 1987) have shown that nonuniformly activated catalysts (catalysts with nonuniform distribution of active sites according to a certain profile)... 

Fu, M.R., 1997. Evaluation of AM/DMDAAC/Na-AMPS in profile modification. Drilling and Production Techniques 20 (5), 60-62. 

The disadvantage of lasers with nanosecond-picosecond pulse duration for depth profiling is the predominantly thermal character of the ablation process [4.229]. For metals the irradiated spot is melted and much of the material is evaporated from the melt. The melting of the sample causes modification and mixing of different layers followed by changes of phase composition during material evaporation (preferential volatilization) and bulk re-solidification [4.230] this reduces the lateral and depth resolution of LA-based techniques. 

This area of research is still at its beginning and many aspects are not resolved. This includes in particular the structure and conformation of polymers at an interface as well as the modification of polymer dynamics by the interface. We have given several examples of the potential of surface and interface analytical techniques. They provide information on surface roughness, surface composition, lateral structure, depth profiles, surface-induced order and interfacial mixing of polymers on a molecular and sometimes subnanometer scale. They thus offer a large variety of possible surface and interface studies which will help in the understanding of polymer structure and dynamics as it is modified by the influence... 

The disposition of insulin was shown to be susceptible to non-absorptive losses to metabolism and mucociliary clearance. Modification of the deposition profile of insulin in the lung showed that higher absorption rates were obtained for more peripheral deposition and co-administration of a metabolic inhibitor reduced losses to exopeptidase metabolism [101], It is acknowledged by the investigators that the IPL technique and the dosing technique of Byron and coworkers are not widely accessible and have therefore not been widely adopted [119], Active absorption has also been studied in this system as described in Sect. 6.2.43. 

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