Reverse bias voltage testing of 8 cm x 8cm silicon solar cells

A study is described of the reverse I-V characteristics of the largest space qualified silicon solar cells currently available (8 x 8 cm) and of reverse bias voltage (RBV) testing performed on these cells. This study includes production grade cells, both with and without cover glass. These cells span the typical output range seen in production. Initial characteristics of these cells are measured at both 28 and 60 C. These measurements show weak correlation between cell output and reverse characteristics. Analysis is presented to determine the proper conditions for RBV stress to simulate shadowing effects on a particular array design. After performing the RBV stress the characteristics of the stressed cells are remeasured. The degradation in cell performance is highly variable which exacerbates cell mismatching over time. The effect of this degradation on array lifetime is also discussed. Generalization of these results to other array configurations is also presented

Simple things: the Alzheimer's space

Modem medicine, science, and technology have created a world where people are living longer and fuller lives. But the price tag for this "time in a bottle" might be greater than we had imagined. As more of the population enters their "Golden years" they are confronting with serious diseases such as stroke, late onset diabetes, arthritis, and the most sinister of all, Alzheimer's disease. Alzheimer's disease causes an erosion of cognitive ability, which ultimately results in death. Due to the fact that there is currently no cure for the disease, treatment focuses on symptoms and maintaining the general health of the sufferer. As the mind looses footing in its battle with the disease, it becomes increasingly important that other outside sources pick up the lost slack. The struggle of those stricken with Alzheimer's disease warrants an exploration in to how space and spatial qualities can be manipulated to create an environment that will, in tandem with treatment, boost the well being of the resident. The seriousness of Alzheimer's disease places a great demand and responsibility on the shoulders of architects and designers to become more enlightened and informed. By understanding the nature of Alzheimer's disease and its symptoms, a design response can be developed that will greatly benefit those living with dementia. The aim of this Masters candidature is to explore and create design projects, in the context of the interior environment, which will provide the Alzheimer's sufferer with the support and stimulation needed to live a dignified life in the face of their ever-changing, ever- unfolding disease

High frequency energy measurements

High-frequency (> 100 MHz) energy measurements present special problems to the experimenter. Environment or available electronics often limit the applicability of a given detector type. The physical properties of many detectors are frequency dependent and in some cases, the physical effect employed can be frequency dependent. State-of-the-art measurements generally involve a detection scheme in association with high-speed electronics and a method of data recording. Events can be single or repetitive shot requiring real time, sampling, or digitizing data recording. Potential modification of the pulse by the detector and the associated electronics should not be overlooked. This presentation will review typical applications, methods of choosing a detector, and high-speed detectors. Special considerations and limitations of some applications and devices will be described

Gallium Arsenide Photocathode For The Free Electron Laser

The efforts of the FEL source have been concentrated on cesiated GaAs(100) wafers. These crystals have shown photoyield of <.1 to 9% quantum efficiency with the cesium and oxygen treatment. The work function and coverage curves exhibit the same properties as measured in the literature. The use of Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy have been instrumental in determining the surface cleanliness and the surface oxidation states. The sputtered surfaces have been investigated as a function of rare gas mass and sputter ion voltage, giving similar results to earlier literature values. Temperature annealing appears to be critical after sputter cleaning in achieving any significant photoyield. Contacts of Ag-Mn and Ni-Si have been deposited, heated, and analyzed using Auger Depth Profiling techniques. 16 refs., 9 figs