14,894 research outputs found
Real-time programmable acoustooptic synthetic aperture radar processor
The acoustooptic time-and-space integrating approach to real-time synthetic aperture radar (SAR) processing is reviewed, and novel hybrid optical/electronic techniques, which generalize the basic architecture, are described. The generalized architecture is programmable and has the ability to compensate continuously for range migration changes in the parameters of the radar/target geometry and anomalous platform motion. The new architecture is applicable to the spotlight mode of SAR, particularly for applications in which real-time onboard processing is required
Organic photovoltaic bulk heterojunctions with spatially varying composition
Models of organic bulk heterojunction photovoltaics which include the effect
of spatially varying composition of donor/acceptor materials are developed and
analyzed. Analytic expressions for the current-voltage relation in simplified
cases show that the effect of varying blend composition on charge transport is
minimal. Numerical results for various blend compositions, including the
experimentally relevant composition of a donor-rich region near the cathode (a
"skin layer" of donor material), show that the primary effect of this variation
on device performance derives from its effect on photocharge generation. The
general relation between the geometry of the blend and its effect on
performance is given explicitly. The analysis shows that the effect of a skin
layer on device performance is small.Comment: 6 pages, 5 figure
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