The Wigner method of transforming quantum-mechanical operators into their phase-space analogs is reviewed with applications to scattering theory, as well as to descriptions of the equilibrium and dynamical states of many-particle systems. Inclusion of exchange effects is discussed.

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Optimum dimensions of circular fins of trapezoidal profile with variable thermal conductivity and heat transfer coefficients are obtained. Linear variation of the thermal conductivity is considered of the form k = k0(1 + εT/T0), and the heat transfer coefficient is assumed to vary according to a power law with distance from the bore, expressed as h = K[(r − r0)/(r0 − re)]m. The results for m = 0, 0.8, 2.0, and −0.4 ≤ ε ≤ 0.4, have been expressed by suitable nondimensional parameters which are presented graphically. It is shown that considering the thermal conductivity as constant, the optimum base thickness and volume of the fin are inversely proportional to the thermal conductivity of the material of the fin, while the optimum length and effectiveness are independent of the properties of the material used.

Total cross sections have been measured for electron scattering on H2 and N2 in the 4-300 eV energy range utilizing a linear attenuation technique. The present results are compared with existing experimental data of other groups in this energy range where good agreement with other experimental data is found.