Cis- and trans-linalool 3,7-oxides and methyl salicylate glycosides and (Z)-3-hexenyl beta-D-glucopyranoside as aroma precursors from tea leaves for oolong tea

Two new alcoholic aroma precursors, cis- and trans-linalool, 3,7-oxides 6-O-beta-D-apiofuranosyl-beta-D-glucopyranosides (1 and 2), as well as two already known compounds, (Z)-3-hexenyl beta-D-glucopyranoside (3) and methyl salicylate 6-O-beta-D-xylopyranosyl-beta-D-glucopyranoside (beta-primeveroside: 4), and another new monoterpendiol glycoside, 8-hydroxygeranyl beta-primeveroside (5) have recently been isolated as aroma precursors in tea leaves (Camellia sinensis var. sinensis cv. Maoxie) ready for oolong tea processing.     

Syntheses and properties of surfactants containing organometals: IV. Organo silicone

The authors synthesized nonionic surfactants containing dimethylpolysilane, dimethylpolysilmethylene and dimethylopolysiloxane as the hydrophobic groups, and investigated their surface activities. In their ability to lower the aqueous surface tension, the polysiloxane surfactants were the most active, and there is little reason to choose between the other two kinds of surfactants. With regard to the ability of lowering the interfacial tension between water and silicone oil, the polysilmethylene surfactants were most effective when the concentration of aqueous solution was below 0.5 wt %. Above this concentration, however, the polysiloxane surfactants were superior. Also investigated was the lowering of surface tension of nonaqueous polyols and their ability to wet low energy hydrophobic surfaces such as polyethylene.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperature. II. Optical strain of remaining stress type

Previously it was found that casting could be carried out efficiently without strain formation by radiation-induced polymerization of glass-forming monomers. Two types of strain were observed in casting: thermal stream type, which was studied previously, and remained stress type. In this report, the effect of various factors on the formation of remaining stress-type strain in radiation-induced casting polymerization was studied. It was found that the molecular weight of prepolymer did not affect strain formation, while prepolymer concentration and viscosity of the system had a serious influence on strain formation. It could be deduced that this type of strain formed as a result of remaining inner stress due to poor relaxation of the shrinking stress. It was realized that less volume shrinkage of glass-forming monomers accompanying casting polymerization reduced the strain formation of this type in radiation-induced casting polymerization at low temperatures.     

Sensitivity analysis of bubble size and probe geometry on the measurements of interfacial area concentration in gas-liquid two-phase flow

Interfacial area concentration measurement is quite important in gas-liquid two-phase flow. To determine the accuracy of measurement of the interfacial area using electrical resistivity probes, numerical simulations of a passing bubble through sensors are carried out. The two-sensors method, the four-sensors method and the correlative method are tested and the effects of sensor spacing, bubble diameter and hitting angle of the bubbles on the accuracy of each measurement method are investigated. The results indicated that the two-sensors method is insensitive to the ratio between sensor spacing and bubble diameter, and hitting angle. It overestimates the interfacial area for small hitting angles while it gives a reasonable accuracy for smaller bubbles and large hitting angles. The four-sensors method gives accurate interfacial area measurements particularly for the larger bubble diameters and smaller hitting angles, while for smaller bubbles and larger hitting angles, the escape probability of bubbles through the sensors becomes large and the accuracy becomes worse. The correlative method gives an overall accuracy for interfacial area measurement. Particularly, it gives accurate measurements for larger bubbles and larger hitting angles while for smaller hitting angles, the spatial dependence of the correlation functions affects the accuracy.     

Low Temperature Phase Transition in C70 and Solvation Effects

The heat capacity of C₇₀ has been measured by adiabatic calorimetry between 14 and 320 K. The orientational phase transition is observed as a broad hump in the heat capacity curve, which is strongly influenced by small amount of solvent remaining in the sample.     

A surface acoustic wave on a ferroelectric layer-structure oxide

As a piezoelectric application of a ferroelectric material of layer-structure type, a surface acoustic wave device using a ceramic Pb_0.15 (NaBi)_0.425Bi₄Ti₄O₁₅, produced by a hot-forging technique is described. The surface acoustic wave on the substrate with the poling axis parallel to the free surface is Blustein-Gulyaev type and its velocity is 2812 m/s.