Two-dimensional infrared correlation spectroscopy as a probe of sequential events in the diffusion process of water in poly(ε-caprolactone)A multitype random sequential processThe effect of an internal electric field and the variation of equilibrium lattice vacancy concentration was incorporated into the continuity equations for the treatment of impurity diffusion in semiconductors. After the explanation of dominant mechanisms involved in the interactions, formulations of the sequential diffusion process and its solution are outlined and numerical results are given. It is shown that the base impurity profile generally experiences a strong retardation by the internal field, resulting in a pro£le much different from what is generally conceived. Important physical and process parameters of this effect are the extrinsicity factor a (defined as the ratio of impurity surface concentration to twice the intrinsic carrier concentration), the base to emitter diffusivity ratio, and the relative diffusion distance of the base initial profile and the emitter profile. Effect of interaction on the emitter profile is mainly due to the variation of vacancy concentration with doping concentration. In the cases considered, comparisons are made between interacting and noninteracting impurity profiles. One implication particularly emphasized is that sequentially diffused transistor profiles constructed by the superposition method can involve large errors even with accurate experimental data on the single diffused emitter and base profiles. The computed transistor profiles from a boron-arsenic sequential diffusion process, based on the model combining the effect of internal field and vacancy concentration variation, agreed well with the experimental results.

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Catalysis, particularly metal-catalyzed reactions in microemulsion systems, offers a sustainable approach for organic reactions in water. However, it is still a challenging task because of the complex role of the nonionic surfactant in such a system and the interaction of the phase behavior and reaction performance. To get a profound knowledge of this role and interaction, a systematic study of the palladium-catalyzed hydroxycarbonylation of 1-dodecene in a microemulsion system is reported. The influence of the temperature, additives such as cosolvents, the catalyst concentration, and the hydrophilicity of the surfactant and its concentration has been investigated with regard to both the phase behavior and reaction performance. Interestingly, the investigations reveal that not the phase behavior of the microemulsion system but mainly the dimension of the oil–water interface and the local concentrations of the substrates at this interface, which is provided by the amount and hydrophilicity of the surfactant, control the reaction performance of hydroxycarbonylation in these systems. Moreover, it was found that the local concentration of the active catalyst complex at the interface is essential for the reaction performance. Dependent on the surface active properties of the catalyst complex, its bulk concentration, and the nature and amount of additives, the local concentration of the active catalyst complex at the interface is strongly influenced, which has a huge impact on the reaction performance.

Das Elektrochromiespektrum von Lutein wird im Dünnschichtkondensator gemessen. In Übereinstimmung mit theoretischen Überlegungen einer vorhergehenden Arbeit ist die Absorptionsänderung proportional dem Quadrat der elektrischen Feldstärke und der ersten Ableitung des Absorptionsspektrums nach der Wellenzahl. Für eine quantitative Auswertung ist die Orientierung der Luteinmoleküle in den Schichten von Interesse. Diese wird durch Messung des Dichroismus untersucht. Die Moleküle haben eine Vorzugsorientierung in Längsrichtung des Objektträgers (Bewegungsrichtung beim Aufziehen der Schichten). ‐ Die Polarisierbarkeitsdifferenz zwischen Grund‐ und Anregungszustand in Richtung der Längsachse eines Luteinmoleküls beträgt ∼910 Å3. Das Elektrochromiespektrum stimmt gut mit lichtinduzierten Absorptionsänderungen von Chromatophoren des Photobakteriums Rhodopseudomonas spheroides überein. Aus dem quantitativen Vergleich muβ man fordern, daβ die Carotinoidmoleküle in der Photosynthesemembran ‐ zusätzlich zu dem lichtinduzierten elektrischen Feld ‐ einem permanenten Feld von ∼1,5. 106 V/cm ausgesetzt sind.