Ultrasonic study of liquid-quenched (AgI) x (Ag3PO4)1−x compared with (AgI) x (Ag4P2O7)1−x

The use of ultrasonic velocity-attenuation in the transition region from glassy to supercooled liquid state of the (AgI) _x (Ag₄P₂O₇)_1–x system is extended to the (AgI) _x (Ag₃PO₄)_1–x system. Comparison is made between both systems. The latter system is more liable to crystallize on cooling from the melt during sample preparation, possibly due to the more spherical shape of the Ag₃PO₄ molecule compared to the Ag₄P₂O₇ molecule (allowing easier rearrangement of the molecule for crystallization with AgI). By deliberate quenching one can escape crystallization, but only for the x=0.75 composition. Ultrasonics for this glass reveal structural features which are similar to those observed by differential scanning calorimetry.     

Melting temperatures of some simple inorganic compounds: an approach by Lindemann's theory

By introduction of ionicity into Lindemann's one-phase theory on melting temperature, a semi-empirical formula for melting temperature of simple compounds, $$T_m \doteqdot {{f_i C_i } \mathord{\left/ {\vphantom {{f_i C_i } {r_{AB} }}} \right. \kern-\nulldelimiterspace} {r_{AB} }} + {{f_c C_c } \mathord{\left/ {\vphantom {{f_c C_c } {r_{AB^{2.5} } }}} \right. \kern-\nulldelimiterspace} {r_{AB^{2.5} } }}$$ has been given, whereT _m,f _i,f _c andr _AB stand for melting temperature, ionicity, covalency and bonding distance, respectively.C _i andC _c are numerical factors which are common to a group of compounds of similar character (crystal structure, valency, etc). Application of Sanderson's ionicity scale to the formula shows good agreement with the observed melting temperatures of alkali halides. A good agreement is also obtained for single oxides. From application of the formula to alkali halides, it is suggested that an anion plays an important role in melting. Similarity ofC _i andC _c in alkali halides of NaCl structure and MO-type oxides of the same structure suggests that melting occurs at almost the same critical position in Lindemann's model for melting in both types of compound.     

Analysis of thickness-extensional waves propagating in the lateral direction of solidly mounted piezoelectric thin film resonators

In a solidly mounted piezoelectric thin film resonator (SMR), acoustic waves propagate not only in the thickness direction but also in the lateral direction. In this study, we analyzed the acoustic wave in the SMR-type piezoelectric thin film resonator and derived the dispersion relation between the lateral wave number and frequency, considering wave propagation in the lateral direction. The lateral wave number was shown to be a complex number due to the leak of the acoustic energy to a substrate. It also was shown that the Q factor could be calculated from the complex cutoff frequency, and it becomes higher when the number of quarter-wave (lambda/4) layers increases. Using the dispersion relation, the trapped-energy resonant modes of an SMR were analyzed, considering the boundary conditions at the edge of the electrode.     

Preparation and surface-active properties of sulfopropylated N-alkylperfluorooctanamides

Sulfopropylation of perfluorooctanamide or its N-alkyl substituted derivatives gave products which were valuable as anionic surfactants. The amides were prepared by the reaction of ethyl perfluorooctanoate with ammonia orn-alkyl amines (C₁-C₁₂), and then treated with 1,3-propanesultone to obtain the desired products. The surfaceactive properties of these compounds were investigated to elucidate the correlation with the chain length of the N-alkyl group. Thus, generally speaking, the N-butyl derivative was found to exhibit properties superior to the others.     

Thermally stimulated currents in lithium-sodium disilicate glasses

Thermally stimulated polarization and depolarization currents were measured for thin films of lithium-sodium disilicate glasses. As reported previously two thermally stimulated depolarization current peaks were found. The low-temperature peak was attributed to conduction polarization of alkali ions, while the high-temperature was attributed to localized motion of non-bridging oxygens in the alkali-depleted region near the anode rather than to space charge or interfacial polarization, as proposed earlier. Although the high-temperature peak was dominant under medium polarizing conditions, it was swept away irreversibly by biasing at extremely high electric field.     

Dissolution inhibition mechanisms of naphthoquinone diazides

Dissolution inhibition mechanisms of naphthoquinone diazides in novolak based positive photoresists were investigated from three different aspects:

• ? Dipolar interaction.
• ? Interfacial chemical reactions.
• ? Chemical structures of naphthoquinone diazides.

The results suggest that there exists a hydrogen bonding interaction between the compounds with the matrix novolak resin and that naphthoquinone diazides would crosslink the resin in contact with an alkaline developer, both of which contribute to dissolution inhibition mechanisms. However, there seems to exist another dissolution inhibition mechanism; namely, 1,2-naphthoquinone diazide does not inhibit dissolution of the matrix novolak resin at all while a clear dissolution inhibition effect Is observed for its derivatives containing sulfonyl groups. In the present paper, three dissolution inhibition mechanisms of naphthoquinone diazides will be proposed.