Thermomechanical Properties of Frozen Sucrose Solutions

A thermomechanical (TMA) method was used to study the glass transition of dry amorphous sucrose and the physical changes occurring when frozen sucrose solutions were heated. A modified TMA device allowed the detection of changes in sample dimension and compliance. Results of the TMA study of sucrose solutions suggested that the maximum solute concentration of the amorphous solution was close to 80% (w/w). In nonmaximally freeze concentrated solutions, devitrification generally started at the glass transition temperature of the amorphous phase and continued up to -32°C, where melting of ice crystals began, inducing softening and flow. With dilute solutions, ice recrystallization occurred in the temperature range from–32 to - 10°C. Devitrification and recrystallization had a stabilizing effect on mechanical properties.     

Electrical, X-Ray, and Thermal Expansion Studies in the System KNbO3-AgNbO3

Unlike the KNbO₃-NaNbO₃ system, the KNbO₃-AgNbO₃ system possessed a very limited degree of solid solution between its end-members. Solid solution of AgNbO₃ in KNbO₃ was limited to slightly less than 6 mole %, and solid solution of KNbO₃ in AgNbO₃ was limited to less than 0.5 mole %. Because of a tendency for the K_{1- x} Ag _x NbO₃ system to lose oxygen spontaneously during firing when 0.06 ≤ x ≤ 0.995, the system could not be treated as a true binary system. The compositions in the KNbO₃ solid solution region (0 ≤ x < 0.06) were ferroelectric at room temperature. Lattice parameter, relative permittivity, and thermal expansion measurements were made on specimens in the region 0 ≤ x ≤ 0.06.     

溶胶-凝胶法制备复合钒钼酸铵干凝胶薄膜及其湿敏特性研究

通过溶胶－凝胶法制备了复合钒钼酸铵Ｈ２－ｘ（ＮＨ４）ｘＶ１０ Ｍｏ２Ｏ３１＋δ＋·ｎＨ２０（ｘ＝０,１,２）干凝胶薄膜,对其进行ＴＸＲＤ和ＸＰＳ分析,同时研究了其温敏性能。     

A six-rhabdomere,open rhabdom arrangement in the eye of the chrysanthemum beetle <i>Phytoecia rufiventris</i>: some ecophysiological predictions based on eye anatomy

We are describing a rhabdom organization of the eye of the chrysanthemum beetle Phytoecia rufiventris that to date has not been described from any other insect. In cerambycid beetles free rhabdomeres, forming a circular, open rhabdom, surround a central rhabdom made up of the rhabdomeres of one or two cells. In Phytoecia rufiventris the central rhabdomeres are missing throughout the eye and the microvilli of the outer 6 rhabdomeres are regularly oriented in three directions. Following the classification of rhabdom types suggested by Wachmann (1979), we suggest to name the rhabdom arrangement seen in the retina of Phytoecia rufiventris “Grundmuster 3”. This pattern ought to facilitate polarization sensitivity and movement perception, features that agree with the behavioural repertoire of Phytoecia rufiventris.     

Surface Crystal Formation During Acid Corrosion of Phosphate-Doped Lead Silicate Glass

The effect of small P₂O₅ additions on the acid corrosion behavior of lead silicate glass was studied at 22°C. Crystals of penta-lead phosphosilicate, a phase heretofore synthesized only by high-temperature melt techniques, formed on the surface of the phosphate-doped glass during the corrosion process. No crystals were observed to form on the pure lead silicate glass. Crystallization appears to result from the controlled release of phosphorus and lead at the glass surface and/or from the reactive catalytic properties of a silica gel surface film. Apparent lead diffusion rates into the acid solution for the phosphate-doped lead silicate glass are much less (by a factor of 11,3) than for the pure lead silicate glass. Application of these findings is suggested in two areas: formulation of low cation-release glass and glaze compositions and the synthesis of high-temperature phases in aqueous solution at ambient temperatures.