QC 351 A7 no. 61 / In an attempt to design a three -mirror aspheric camera, a procedure was developed to arrive at a design with a minimum obscuration ratio. It was found that, in some cases, the sky baffling became the diffracting obscuration rather than the obscuration caused by the secondary. The procedure allowed for this and was able to select a system with the smallest diffracting obscuration in the pupil. Initially, two designs were selected and optimized through the use of aspheric surfaces. The designs represented two extremes in that one had much faster surfaces than the other. The fast mirror system was easier to optimize, performed better, and had the shorter over -all length. Further, evaluation of manufacturing errors on the fast mirror design showed that an acceptable level of performance could be expected if the errors were kept small. The maximum errors are spacing errors ±0.0005 in. tilt of surface errors ±0.001 /D in. radii of curvature errors ±0.125 in. where D is the diameter of the mirror surface.

Thesis (M.Sc.Eng.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This thesis presents an integrated driver for deformable mirror array based on the architecture proposed in Horenstein, et al's "Ultra-low power multiplexed electronic driver for high resolution deformable mirror systems." The integrated driver consists of numerous high voltage (HV) analog switches connecting the deformable mirror cells, on demand by low-voltage digital control signals, to the HV analog signal line, and a HV power amplifier used to drive the HV analog signal line. The reduction of power consumption is essential in both HV power amplifier and analog switch designs for utilization of deformable mirror systems in space-based applications. In addition to low power design, this work also focuses on the analysis and design of multi-stage amplifier capable to drive large load capacitor, and HV analog switch robust to analog signal noise during OFF state. The specific research contributions of this work include (1) A feed-forward stage in combination with a class B output stage is proposed in the HV multi-stage power amplifier structure to improve the large-signal performance when driving large capacitive load. (2) A low voltage level-shifter and a voltage clamp are added in conventional HV analog switch to reduce the interference from the noisy analog signal line. / 2031-01-01

Imaging has revealed that brain activation of verbs with verifiable products (‘throw, kick’) activate language areas as well as the motor cortex responsible for the performance of the action described. An exploratory comparison of eye related verbs with no verifiable products (‘observe’) to mouth related verbs with verifiable products (‘shout’) has revealed a similar activation pattern. Thus in order to further study mental action verbs with no verifiable products, the present two-part study used words that were suitable across two modalities (e.g. you can ‘perceive’ both through vision and audition) and compare them to themselves under differing contexts of auditory and visual verbs so as to eliminate any word characteristics differences, as well as explored the two modalities directly. The primary purpose was to delineate whether associative learning or the mirror systems theory might better account for the acquisition of this unique subclass of verbs. Results suggest that Mirror systems theory more likely accounts for the observed cognitive processing differences between the two verbs. Keywords: Verbs, language, Event-related potentials, abstract, associative learning theory, mirror systems theory.