Among five mutagenic compounds isolated from water samples, taken at sites below the sewage plants of the Nishitakase River in Kyoto, Japan, the structure of compound I has been determined to be 2-[2-(acetylamino)-4-[bis(2-methoxyethyl)amino]-5-methoxyphenyl]-5-am ino-7-bromo-4-chloro-2H-benzotriazole (PBTA-1). Since this novel aromatic amine mutagen has characteristic substituents in its molecule, it is postulated that the azo dye, 2-[(2-bromo-4, 6-dinitrophenyl)azo]-4-methoxy-5-[bis(2-methoxyethyl)amino]acetoanili de (AZO DYE-1), used as an industrial material, is converted to the corresponding 2-phenylbenzotriazole derivative with a reducing reagent and subsequently to PBTA-1 by chlorination. In fact, AZO DYE-1 changed to the dechlorinated derivative of PBTA-1 (deClPBTA-1) on treatment with sodium hydrosulfite, and this reacted with sodium hypochlorite to produce PBTA-1. Moreover, the presence of deClPBTA-1 was confirmed in a river water sample, along with PBTA-1. PBTA-1 showed potent mutagenic activities in Salmonella typhimurium TA98 and YG1024, inducing 88 000 and 3 000 000 revertants, respectively, per microg, with S9 mix. deClPBTA-1 was also mutagenic, but less potent. From these observations, it is suggested that PBTA-1 is produced from AZO DYE-1 through deClPBTA-1, during industrial processes at dyeing factories and the treatment of wastewater at sewage plants.

We proposed and demonstrated a new method to extract the charge centroid of metal-oxide-nitride-oxide-semiconductor (MONOS) devices. Comparing with other existing methods for charge centroid evaluation, our new method has the advantage of simplicity and the compatibility with other test sequences of memory cell capacitors. Using our method, we investigated the dependence of charge centroid on the thickness of SiN layer. It is found that the charge centroid of the 14-nm-thick SiN MONOS is located around the middle of the SiN layer, while the 5-nm-thick SiN MONOS has the centroid at the SiN/Al 2 O 3 interface. These results indicate that the available trap sites during program operation are dependent on the thickness of the SiN layer. #

Reaction steps of silicidation in ZrO2/SiO2/Si layered structure have been investigated in terms of ultrahigh vacuum annealing. Comparison of 2- and 20-nm ZrO2 films at 920 °C revealed that the trigger of silicidation is the contact of ZrO2, SiO, and Si accompanying disappearance of interfacial SiO2 layer due to SiO desorption. In the contact position, a small amount of SiO gas can easily change ZrO2 to ZrSi2. Moreover, this reaction model is also applicable to the silicidation of gate polycrystalline-Si (poly-Si)/ZrO2 interface.

The diffusive propagation of electromagnetic waves in an absorbing random medium is studied and the localization corrections to the diffusion coefficient are calculated. The differences between absorption and inelastic scattering are discussed. Unlike inelastic scattering which introduces a cut-off length into the diffusion coefficient without affecting the total intensity, absorption reduces the intensity but cancels out of the diffusion coefficient. It is predicted that a sharp mobility edge can exist in a sufficiently strongly disordered medium even in the presence of a significant degree of absorption. Novel scaling properties of the transmitted waves at the mobility edge are predicted.

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