Search results for "Open cavity"
showing 3 items of 3 documents
Derivatisation of Pyrogallarenes
2005
Derivatisation of upper-rim hydroxy groups of pyrogallarenes produced completely acylated and tosylated pyrogallarene derivatives. Mesitylation of pyrogallarene, however, resulted in a regioselective derivatisation of hydroxy groups, i.e. eight OH groups out of 12 were mesitylated. Crystal structures of the synthesised pyrogallarene derivatives indicate that completely substituted pyrogallarenes exist in a distorted crown conformation despite of the lack of stabilising intramolecular hydrogen bonds. In contrast, the partially substituted pyrogallarene adopts a boat conformation and has an open cavity for the inclusion of small guest molecules. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinh…
Quasi-Normal Frequencies in Open Cavities: An Application to Photonic Crystals
2005
The electromagnetic field in an optical open cavity is analyzed in the framework of the Quasi-Normal Modes theory. The role of the complex quasi-normal frequencies in the transmission coefficient and their link with the density of quasi-modes function is clarified. An application to a quarter-wave symmetric one-dimensional photonic crystals is discussed to illustrate the usefulness and the meaning of our results.
Cholesteatoma of the hypotympanum in a patient with Treacher Collins syndrome
2014
In the present article we report a cholesteatoma of the hypotympanum extending to the jugular foramen in a 16-year-old male with Treacher Collins syndrome. Preoperative imaging excluded jugular paraganglioma and set the diagnosis of cholesteatoma. We discuss the operative treatment via a large hypotympanotomy and creation of an open hypotympanic cavity. To the authors' knowledge this is the first description of hypotympanal cholesteatoma with such an extension, being treated through this approach.