In this paper we study the existence of pullback global attractors for multivalued processes generated by differential inclusions. First, we define multivalued dynamical processes, prove abstract results on the existence of -limit sets and global attractors, and study their topological properties (compactness, connectedness). Further, we apply the abstract results to nonautonomous differential inclusions of the reaction–diffusion type in which the forcing term can grow polynomially in time, and to stochastic differential inclusions as well. 相似文献
Poly(ethylene glycol) (PEG)‐interlocked hydrogels were prepared by linking the PEG with α‐cyclodextrins (α‐CDs) threaded onto a PEG chain having ester linkages at the terminals (hydrolyzable polyrotaxane). These hydrogels were examined to clarify the effect of ionic strength of phosphate buffers, pH, and the addition of ethanol on erosion time in relation to inclusion states of α‐CDs with the ester linkages. The most characteristic phenomenon of the hydrogel erosion was observed in an ethanol/PBS cosolvent system: the time to reach the complete erosion time was shortened with decreasing water content. NMR analysis revealed that the ester linkages were exposed to the aqueous environment due to the aggregation of α‐CDs. These results suggest that the movement of α‐CDs in the polyrotaxanes from the terminal ester region to the another region gives the ester linkages a chance to interact with water.
The reaction of -cyclodextrin (1) with palmitoyl (2) and valeryl (4) chlorides in DMF or Py, unlike previously studied acetylation of 1, involves only the primary hydroxy groups of 1. The outcome of the reaction depends on the reaction conditions and the nature of the acid scavenger used (Et3N, Pri2NEt, PhNMe2, Py). 13C NMR spectroscopy was shown to be an effective tool in determining the number and position of aliphatic carboxylic acid residues introduced into 1. A hypothesis stating that preliminary formation of a reactive inclusion complex (acid chloride1) is required for the acylation of 1 to occur is proposed and substantiated. This hypothesis provides a unified explanation for a variety of unusual facts observed in the acylation of 1 and its derivatives. 相似文献
The mineral inclusions in accessory minerals of the country gneisses have been studied in order to interpret relation between
eclogites and their country gneissic rocks. Omphacite inclusions have been identified in titanite and zircon, which indicates
that the present mineral assemblages of country gneisses are the last retrograded assemblages and eclogites and their country
gneissic rocks probably have a same metamorphic history. 相似文献