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A thermophysical study of 1-butyl-2-methylpyridinium tetrafluoroborate in a wide range of temperatures has been performed. Thus, density, speed of sound, refractive index, kinematic viscosity, surface tension, and thermal properties have been measured, whereas coefficients of thermal expansion, molar refractions, dynamic viscosities, and entropies and enthalpies of surface formation per unit surface area at the studied temperatures have been calculated. Experimental results have been compared with those obtained for 1-butyl-3-methylpyridinium tetrafluoroborate and 1-butyl-4-methylpyridinium tetrafluoroborate to analyze the effect of the positional isomeric cationic structure on properties. A systematic characterization leads to understand the behavior of such compounds, being a fundamental step to develop their potential as new solvents.

The electron donor-acceptor abilities of some cyclic ethers (tetrahydropyran or tetrahydrofuran), benzene, and halobenzenes (fluorobenzene or chlorobenzene) and the molecular interactions between these compounds have been investigated through a wide set of thermodynamic mixing properties of their mixtures. The mixing properties have been derived from experimental measurements of density, speed of sound, refractive index, surface tension, heat of mixing, and vapor-liquid equilibrium at the temperature of 298.15 K.

Abstruct-Germanium MOSFET's which can be fabricated by a process which is suitable for integration are of interest for application to monolithic optical fiber receivers operating in the 1.3-1.55-fim range and for future low-temperature CMOS circuits. The fabrication and performance of self-aligned germanium MOSFET's which utilize a nitrided native oxide gate insulator are reported. Based on device characteristics, channel mobility at 300 K is estimated as 940 cm2/V.s. Common-source characteristics show good saturation and turn-off, and do not exhibit "looping" or other anomalies. These results suggest that a number of the technological problems surrounding the implementation of germanium integrated circuits are tractable.