The effects of hydrogen on aluminum-induced crystallization of sputtered hydrogenated amorphous silicon

The effects of hydrogen on aluminum-induced crystallization (AIC) of sputtered hydrogenated amorphous silicon (a-Si:H) were investigated by controlling the hydrogen content of a-SiH films. Nonhydrogenated (a-Si) and hydrogenated (a-Si:H) samples were deposited by sputtering and plasma-enhanced chemical vapor deposition (PECVD). All aluminum films were deposited by sputtering. Hydrogen was introduced into the sputter-deposited a-Si films during the deposition. After deposition, the samples were annealed at temperatures from 200°C to 400°C for different periods of time. X-ray diffraction (XRD) patterns were used to confirm the presence and degree of crystallization in the a-Si:H films. For nonhydrogenated films, crystallization initiates at a temperature of 350°C. The crystallization of sputter-deposited a-Si:H initiates at 225°C when 14% hydrogen is present in the film. As the hydrogen content is decreased, the crystallization temperature increases. On the other hand, the crystallization initiation temperature for PECVD a-Si:H containing 11at.%H is 200°C. Further study revealed that the crystallization initiation temperature is a function, not only of the total atomic percent hydrogen in the film, but also a function of the way in which the hydrogen is bonded in the film. Models are developed for crystallization initiation temperature dependence on hydrogen concentration in a-Si:H thin films.     

Repelling the young and attracting the old: Examining age-related differences in saccade trajectory deviations.

In the present study, the authors examined age-related differences in saccade curvature as older and younger adults looked to an X target that appeared concurrently with an O distractor. They used a fixation gap procedure to introduce variance into the saccadic latencies of both groups. Consistent with earlier findings, younger adults' early onset saccades curved toward the distractor (as the distractor competed with the target for response selection), while late-onset saccades curved away from the distractor (as the distractor location became inhibited over time). In contrast, older adults' saccades gradually decreased in curvature toward the distractor, but at no point along the latency continuum did they show deviations away. These results suggest that while the local inhibitory mechanisms responsible for decreases in curvature toward distractors may be preserved with age, aging may lead to a selective decline in the frontal inhibitory mechanisms responsible for deviations away from distractors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Arsenic-implanted thin film PECVD semi-insulating polysilicon (SIPOS) resistors

Thin film (2000Å) PECVD SIPOS resistors were fabricated using arsenic implantation and rapid thermal annealing. The current-voltage characteristics are symmetrical and field-dependent. The resistivity (as low as 0.2 ohm-cm) is shown to be a function of the oxygen content of the as-deposited material, the implant dose, and the annealing temperature. The variation of resistance with operating temperature also decreases with increasing dose and annealing temperature. As expected, the lowest resistivity is obtained for films with high refractive indices or alternatively, low oxygen content. *This work was supported by a research contract from Sandia National Lab.     

Layoffs and tradeoffs: Production, quality, and safety demands under the threat of job loss.

Employees often face a conflict between production targets, quality assurance, and adherence to safety policies. In a time when layoffs are on the rise, it is important to understand the effects of employee job insecurity on these potentially competing demands. A laboratory experiment manipulated the threat of layoffs in a simulated organization and assessed its effect on employee productivity, product quality, and adherence to safety policies. Results suggest that student participants faced with the threat of layoffs were more productive, yet violated more safety rules and produced lower quality outputs, than participants in the control condition. Implications for organizations contemplating layoffs and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of temperature on structural and magnetic properties of Co0·5Mn0·5Fe2O4 ferrites

Co_0·5Mn_0·5Fe₂O₄ ferrites have been synthesized using a single-step sol-gel auto-combustion method in which the metal nitrate (MN)-to-citric acid (CA) ratio was adjusted to 0.5: 1 and pH to 7, respectively. The structural and magnetic properties of as-burnt and annealed samples were studied as a function of temperature. The inverse spinel structure was confirmed by X-ray diffraction (XRD) and crystallite size was estimated by the most intense peak (311) using Scherrer’s formula. Contrary to earlier studies reported in the literature, both as-burnt and annealed samples exhibit crystalline behaviour. Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM) with field strengths up to ±10 kOe. Lattice constant and crystallite size increased as the annealing temperature was increased. However, the coercivity (H _c) initially increased and then decreased with the increase of crystallite size. The variation in coercivity is ascribed to the transition from a multi-domain to a single-domain configuration.     

Melanoma localization and classification through faster region-based convolutional neural network and SVM

Multimedia Tools and Applications - Melanoma is a lethal skin cancer disease affecting millions of people around the globe and has a high mortality rate. Dermatologists perform the manual...     

MRT letter: Quantum noise removal and classification of breast mammogram images

Because of the limitations of the X‐ray hardware systems in mammogram machines, the quality of the breast mammogram images may undergo from poor resolution or low contrast. Quantum noise occurs in the mammogram images during acquisition due to low‐count X‐ray photons. In this work, an adaptive frost filter has been used to remove quantum noise. Local binary patterns have been extracted to classify breast mammograms into benign and malignant using different classifiers. Results show the superiority of the proposed algorithm in terms of sensitivity, specificity, and accuracy. Mammographic Institute Society Analysis database of mammography has been used for experimentation. Peak signal‐to‐noise ratio and structural similarity index measure are used to test the validity of adaptive frost filter. Experiment results show that proposed technique produces better results. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Microstructure,optical and dielectric properties of cobalt-doped zinc ferrite nanostructures

Journal of Materials Science: Materials in Electronics - In the present work, we have explored the physical properties of ZnFe2?xCoxO4 (0?≤?x?≤?0.06)...     

Characterization of biodegradable poly(l-lactide) tube over accelerated degradation

The next-generation bioresorbable polymeric stents are undergoing continual research and development, especially how to control and optimize their degradation behaviors. The aim of this paper is to study the properties of a poly(l -lactide) (PLLA) tube over accelerated degradation in vitro. Spherical nanoindentation was particularly adopted to measure the mechanical properties of PLLA tube; while differential scanning calorimetry and gel permeation chromatography were used for crystallinity and molecular weight measurements. Overall, the material degradation was captured by the local stress-strain response obtained with spherical nanoindentation, and further confirmed with chemical analyses. The results are particularly useful for development of bioresorbable polymeric stents with improved performance.