Engineering topics
Publications and source records attributed to Pittman, R..
Ballistic-electron-emission microscopy (BEEM) and spectroscopy have been used to investigate the properties of Au/GaN interfaces.
Explore the source record for details and available documents.
Ballistic-electron-emission (BEEM) and spectroscopy have been used to characterize the Pd/GaN and Au/GaN interfaces.
Explore the source record for details and available documents.
BEEM spectroscopy and imaging have been applied to the Au/GaN interface. In contrast to previous BEEM measurements, spectra yield a Schottky barrier height of 1.04eV that agrees well with the highest values measured by conventional methods.
NASA is currently exploring the feasibility of developing a large deployable reflector (LDR) astronomical facility to perform astrophysical studies in the mid 1990's in the IR and submillimeter portion of the spectrum. This paper examines a combination of automatic deployment and on-orbit assembly that may reduce the technological complexity and cost of the LDR system. Two Shuttle volume budget scenarios are examined to assess the potential of various technological tools to reduce the LDR system complexity. It is noted that the LDR design must be flexible and allow one subsystem to be modified without adversely affecting the entire system. One way to achieve this flexibility is a modular design approach (MDA) in which the major subsystems are physically separated during launch and assembled on orbit. NASA is defining a technology development plan for LDR that will identify the technology advances that are required. It is concluded that the MDA offers the flexibility to easily incorporate these advances into the design.