Tsuneo Ikenoue

N.m.r. study of the self-association of ethyl and t-butyl alcohols in nonpolar solvents

N.m.r. dilution shifts of OH protons in ethyl and t-butyl alcohols have been measured in benzene, carbon tetrachloride and cyclohexane. The results were analysed on the basis of a linear association model and the association constants were estimated. The constants for ethyl alcohol were about twice as large as those for t-butyl alcohol in the same solvent. Excess Gibbs free energy and activity coefficients for the ethyl alcohol + cyclohexane mixture were calculated by employing equations derived from Florys theory of high polymer solutions.

Modified variable temperature control unit for NMR spectrometers

A variable temperature control unit for NMR spectrometers was modified to improve the accuracy of the temperature setting and to suppress the drift and fluctuation of the sample temperature within ±0.1 °C.

New circuit for a constant voltage supply using series‐shunt regulation

A new circuit for constant voltage supply with series-shunt regulation has been designed to improve the suppression ratio of the incoming fluctuating noise. A typical example applicable to instruments with high sensitivity is also reported.