Removal of phthalic acid esters (PAEs) by the formation of inclusion complexes with β-cyclodextrin (β-CD) in aqueous solution was studied. According to the measure ments of fluorescence and NMR spectroscopy, it was confirmed that PAEs were included into the β-CD cavity. The stability constants of the β-CDPAE complexes were varied depending on the alkyl chain length of the PAEs. The adsorption isotherms of PAEs and β-CD polymer (β-CDP) were well described by Freundlich isotherm equations, and the adsorption capacity varied according to the stability constant. PAEs were well adsorbed by β-CDP both in batch and in a column system, and the PAEs were also released from β-CDP by shaking with a mixture of methanol and water. The recovery efficiency was varied with the mixture ratio of methanol and water, and the recovered β-CDP was reusable as an adsorbent.

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The physical properties and charge trapping behavior of rapid thermal N2O-oxynitrided (RTON) and rapid thermal NH3-nitrided (RTN) ultrathin SiO2 films have been investigated. The results of secondary-ion-mass spectrometry and Fourier transform infrared reflection measurements indicate that although nitrogen atoms are incorporated into the RTON and RTN films, only the RTN film shows a large number of NH bonds in the bulk SiO2. Using an analytical model, the number of oxide charge traps, the capture cross section, and the charge trap generation rate for the RTON and RTN SiO2 films were determined. Under high-field stress, the RTON SiO2 film has a much smaller number of electron and hole traps and a lower electron trap generation rate, resulting in a larger charge-to-breakdown QBD value compared to that of pure SiO2 film. In contrast, a large number of electron traps which originate from NH and SiH bonds is present in the RTN film. The differences in the charge trapping phenomena and oxide breakdown characteristics are strongly related to the chemical bonding state in the bulk oxide.

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