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The forward current transfer ratio (hFE = (AIcollector /AIbase)) of a germanium junction transistor, operating in the common emitter mode, is reduced by the application of a magnetic field. This reduction is greatest when the magnetic field vector is perpendicular to the direction of minority carrier motion through the base region. The base thickness is also an important variable. Transistors with smaller base (planar diffused) regions a r e less affected by magnetic fields. Key Words ( S u g g e s t e d b y A u t h o r ( s ) ) Distribution StatementUnclassified -unlimited SUMMARYThe forward current transfer ratio (hFE = (AIcollector /hIbase)) of a germanium junction transistor, operating in the common emitter mode, is reduced by the application of a magnetic field. This reduction is greatest when the magnetic field vector is perpendicular to the direction of minority carrier motion through the base region. The base thickness is also an important variable. Transistors with smaller base (planar diffused) regions are less effected by magnetic fields.

SummaryA new test is described that can be used to measure changes in the vibration properties of impact-damaged composite materials. Impact-induced delamination was observed to significantly affect natural frequencies of vibration and damping properties in cross-ply graphite/epoxy laminates. Natural frequencies are shown to drop by as much as half of their original value, and modal damping ratios can increase by a factor of up to eight when large amounts of damage are present. A simple finite-element model of the damaged impact specimens was used to predict the effect of delamination on certain vibration properties. A comparison of the finite-element calculations with the experimental measurements suggests that delamination was the dominant mechanism of flexural stiffness loss resulting from the transverse impact.

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Performance data are presented for tests of 51-cm-bore single coil and coil pair magnets operated at temperatures below 2°K. The magnet coils are wound of silver-plated, vapor-deposited Nb3Sn ribbon. Coil protection was provided by cross-layer shorting strips which also provide very limited stabilization. Each coil was designed to produce a 4.0-T center field. Results obtained at the low temperature are compared with those obtained at 4.2°K. System description and charging characteristics are included in the discussion.