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- Creators: Computer Science and Engineering Program
- Creators: Bennett, Peter
American Sign Language (ASL) is used for Deaf and Hard of Hearing (DHH) individuals to communicate and learn in a classroom setting. In ASL, fingerspelling and gestures are two primary components used for communication. Fingerspelling is commonly used for words that do not have a specifically designated sign or gesture. In technical contexts, such as Computer Science curriculum, there are many technical terms that fall under this category. Most of its jargon does not have standardized ASL gestures; therefore, students, educators, and interpreters alike have been reliant on fingerspelling, which poses challenges for all parties. This study investigates the efficacy of both fingerspelling and gestures with fifteen technical terms that do have standardized gestures. The terms’ fingerspelling and gesture are assessed based on preference, ease of use, ease of learning, and time by research subjects who were selected as DHH individuals familiar with ASL.
The data is collected in a series of video recordings by research subjects as well as a post-participation questionnaire. Each research subject has produced thirty total videos, two videos to fingerspell and gesture each technical term. Afterwards, they completed a post-participation questionnaire in which they indicated their preference and how easy it was to learn and use both fingerspelling and gestures. Additionally, the videos have been analyzed to determine the time difference between fingerspelling and gestures. Analysis reveals that gestures are favored over fingerspelling as they are generally preferred, considered easier to learn and use, and faster. These results underscore the significance for standardized gestures in the Computer Science curriculum for accessible learning that enhances communication and promotes inclusion.
Layers of gallium phosphide (GaP) grown on silicon (Si) substrates were characterized by TEM and aberration-corrected scanning transmission electron microscopy (AC-STEM). High defect densities were observed for samples with GaP layer thicknesses 250nm and above. Anti-phase boundaries (APBs) within the GaP layers were observed at interfaces with the Si surfaces which were neither atomically flat nor abrupt, contradicting conventional understanding of APB formation.
Microcrystalline-Si (μc-Si) layers grown on crystalline-Si (c-Si) substrates were investigated. Without nanoparticle seeding, an undesired amorphous-Si (a-Si) layer grew below the μc-Si layer. With seeding, the undesired a-Si layer grew above the μc-Si layer, but μc-Si growth proceeded immediately at the c-Si surface. Ellipsometry measurements of percent crystallinity did not match TEM images, but qualitative agreement was found between TEM results and Ultraviolet Raman spectroscopy.
TEM and Xray spectroscopy were used to study metal-induced crystallization and layer exchange for aluminum/ germanium (Al/Ge). Only two samples definitively exhibited both Ge crystallization and layer exchange, and neither process was complete in either sample. The results were finally considered as inconclusive since no reliable path towards layer exchange and crystallization was established.
Plan-view TEM images of indium arsenide (InAs) quantum dots with gallium arsenide antimonide (GaAsSb) spacer layers revealed the termination of some threading dislocations in a sample with spacer-layer thicknesses of 2nm, while a sample with 15-nm-thick spacer layers showed a dense, cross-hatched pattern. Cross-sectional TEM images of samples with 5-nm and 10-nm spacer-layer thicknesses showed less layer undulation in the latter sample. These observations supported photoluminescence (PL) and Xray diffraction (XRD) results, which indicated that GaAsSb spacer layers with 10-nm thickness yielded the highest quality material for photovoltaic device applications.
a-Si/c-Si samples treated by hydrogen plasma were investigated using high-resolution TEM. No obvious structural differences were observed that would account for the large differences measured in minority carrier lifetimes. This key result suggested that other factors such as point defects, hydrogen content, or interface charge must be affecting the lifetimes.