Low-frequency abeorption centers, observed by electrical measurements in single crystals of rutile, can be produced by thermal quenching or optical irradiation in the edge of the eigen absorption region (600 A). They are observed when electric fields are applied parallel to the optic axis (crystallographic c axis) and are not visible with the field perpendicular to this axis. The temperature dependence of the principal dispersion indicates an activation energy of 0.18 ev. The centers can be explained by a localized electron transfer process along the optic axis. The introduction of silver and copper by thermal diffusion did not produce low frequency absorption spectra. (auth)

Report presenting values of the nondimensional normal component of induced velocity throughout the flow field of a uniformly loaded lifting rotor operating in the upper half of the helicopter speed range in the form of graphs and tables. The results obtained should be useful for estimating the induced velocity distribution about lifting rotors in general and for synthesizing the distributions over the rotor disk for the case of any specified non-uniform loading.