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41.
Fibre-optic components fabricated on the same substrate as integrated circuits are important for future high-speed communications. One industry response has been the costly push to develop indium phosphide (InP) electronics. However, for fabrication simplicity, reliability and cost, gallium arsenide (GaAs) remains the established technology for integrated optoelectronics. Unfortunately, the GaAs bandgap wavelength (0.85 microm) is far too short for fibre optics at 1.3-1.5 microm. This has led to work on materials that have a large lattice mismatch on GaAs. Here we demonstrate the first light-emitting diode (LED) that emits at 1.5 microm fibre-optic wavelengths in GaAs using optical transitions from arsenic antisite (As(Ga)) deep levels. This is an enabling technology for fibre-optic components that are lattice-matched to GaAs integrated circuits. We present experimental results showing significant internal optical power (24 mW) and speed (in terahertz) from GaAs optical emitters using deep-level transitions. Finally, we present theory showing the ultimate limit to the efficiency-bandwidth product of semiconductor deep-level optical emitters. 相似文献
42.
Louise Barry Joseph Tobin Mark Copley Justin D. Holmes David J. Otway Michael A. Morris 《Applied Catalysis A: General》2008,341(1-2):8-11
Novel MnS impregnated mesoporous silica systems have been originated for the generation of carbon nanocages. The procedure involves a simple catalytic vapour deposition (CVD) method. This is the first time that a transition metal sulfide has been used for the synthesis of carbon nanostructures. 相似文献
43.
Louise Moody Alan Waterworth Avril D. McCarthy Peter J. Harley Rod H. Smallwood 《Virtual Reality》2008,12(2):77-86
The Sheffield knee arthroscopy training system (SKATS) was originally a visual-based virtual environment without haptic feedback,
but has been further developed as a mixed reality-training environment through the use of tactile augmentation (or passive
haptics). The design of the new system is outlined and then tested. In the first experiment described, the effect of tactile
augmentation on performance is considered by comparing novice performance using the original and mixed reality system. In
the second experiment the mixed reality system is assessed in terms of construct validity by comparing the performance of
users with differing levels of surgical expertise. The results are discussed in terms of the validity of a mixed reality environment
for training knee arthroscopy. 相似文献
44.
Hawkley Louise C.; Thisted Ronald A.; Masi Christopher M.; Cacioppo John T. 《Canadian Metallurgical Quarterly》2010,25(1):132
Loneliness is a prevalent social problem with serious physiological and health implications. However, much of the research to date is based on cross-sectional data, including our own earlier finding that loneliness was associated with elevated blood pressure (Hawkley, Masi, Berry & Cacioppo, 2006). In this study, we tested the hypothesis that the effect of loneliness accumulates to produce greater increases in systolic blood pressure (SBP) over a 4-year period than are observed in less lonely individuals. A population-based sample of 229 50- to 68-year-old White, Black, and Hispanic men and women in the Chicago Health, Aging, and Social Relations Study was tested annually for each of 5 consecutive years. Cross-lagged panel analyses revealed that loneliness at study onset predicted increases in SBP 2, 3, and 4 years later (B = 0.152, SE = 0.091, p 相似文献
45.
Pratt Michael W.; Norris Joan E.; Arnold Mary Louise; Filyer Rebecca 《Canadian Metallurgical Quarterly》1999,14(3):414
Little research so far has examined storytelling as a channel of value socialization. In the present study, 129 adults from 3 age groups (18–26, 28–50, 60–75) were asked to tell stories for adolescents about 2 of their past value-learning experiences. Generative concern (D. P. McAdams & E. de St. Aubin, 1992) and moral reasoning stage level were also assessed. Stronger generative concern was predictive of a greater sense of having learned important lessons from these past events, of stronger adult value socialization investment, and of more engaging narratives for adolescents as judged by a panel of uninstructed raters. Higher levels of moral reasoning were positively related to generative concern and to a stronger sense of past lessons learned. Generativity appears important to the project of value socialization across the adult life span. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
46.
O'Connor Rollanda E.; Bell Kathryn M.; Harty Kristin R.; Larkin Louise K.; Sackor Sharry M.; Zigmond Naomi 《Canadian Metallurgical Quarterly》2002,94(3):474
The authors compared the influence of text difficulty--reading-level matched or grade-level matched--on the growth of poor readers' reading ability over 18 weeks of 1-to-1 tutoring. Forty-six 3rd-5th graders, including 25 with disabilities, were assigned randomly to 1 of 2 tutoring approaches or a control condition. Significant differences favored tutored children. Between approaches, the only significant difference was oral reading fluency, which favored students who read material at their reading level. Students who began with lower fluency made stronger gains in text matched to reading level; students with higher fluency profited from both treatments. When the 3 groups were combined, fluency was the strongest contributor to reading comprehension outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
Mabbott Donald J.; Penkman Louise; Witol Adrienne; Strother Douglas; Bouffet Eric 《Canadian Metallurgical Quarterly》2008,22(2):159
Identifying cognitive deficits associated with pediatric brain tumors and their treatment is important in delineating the mechanisms of intellectual decline often associated with these diseases. The authors evaluated sustained attention, information processing speed, working memory, and IQ in 64 patients with posterior fossa tumors, including those treated with either: (a) surgery and cranial radiation (n = 32), and (b) surgery without radiation (n = 32). Ten patients treated for non-CNS solid tumors were included as a comparison group. The authors also examined the impact of relevant demographic and medical variables on neurocognitive outcome. The authors found that neither age at, nor time since, diagnosis predicted cognitive outcome in this sample. Further, sustained attention and working memory were largely intact and there were no differences between groups. Patients treated with cranial radiation demonstrated lowered short-form IQ and slow information processing speed: Patients treated with cranial radiation and who experienced postsurgical complications demonstrated the poorest performance. The authors consider information processing speed to be an excellent candidate mechanism in understanding the impact of cranial radiation on intellectual outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
It is commonly assumed that attitudes and behaviours need to be modified to secure a sustainable energy future. This paper examines insights from the social sciences in this extensive field. Alongside instruments such as regulation and economic measures, government campaigns have sought to ‘educate’ the public. However, such ‘information deficit’ models have been criticised on theoretical and pragmatic grounds. In the area of energy consumption, there is a need to take account of the physical, social, cultural and institutional contexts that shape and constrain people's choices, and for a richer understanding of opposition to energy facility siting, which has often been (inadequately) characterised as ‘NIMBYism’. Recent work also points to the need for more deliberation and better communication between decision-makers, technical experts, other stakeholders and the public. Predicting future developments in the field is challenging but attention is likely to focus on aspects of policy learning, a more critical examination of the ‘deliberative turn’, and the need for a systemic approach to complex socio-economic and socio-technical systems. The consistency of government objectives across all policy spheres is likely to provide an important avenue for future research. 相似文献
49.
Waseem Hiwar Marco-Felipe King Farag Shuweihdi Louise A. Fletcher Stephanie J. Dancer Catherine J. Noakes 《Indoor air》2021,31(5):1308-1322
Airborne microorganisms in hospitals have been associated with several hospital-acquired infections (HAIs), and various measures of indoor air quality (IAQ) parameters such as temperature, relative humidity, carbon dioxide (CO2), particle mass concentration, and particle size have been linked to pathogen survival or mitigation of pathogen spread. To investigate whether there are quantitative relationships between the concentration of airborne microorganisms and the IAQ in the hospital environment. Web of Science, Scopus and PubMed databases were searched for studies reporting airborne microbial levels and any IAQ parameter(s) in hospital environments, from database inception to October 2020. Pooled effect estimates were determined via random-effects models. Seventeen of 654 studies were eligible for the meta-analysis. The concentration of airborne microbial measured as aerobic colony count (ACC) was significantly correlated with temperature (r = 0.25 [95% CI = 0.06–0.42], p = 0.01), CO2 concentration (r = 0.53 [95% CI = 0.40–0.64], p ˂ 0.001), particle mass concentration (≤5 µg/m3; r = 0.40 [95% CI = 0.04–0.66], p = 0.03), and particle size (≤5 and ˃5 µm), (r = 0.51 [95% CI = 0.12–0.77], p = 0.01 and r = 0.55 [95% CI = 0.20–0.78], p = 0.003), respectively, while not being significantly correlated with relative humidity or particulate matter of size >5 µm. Conversely, airborne total fungi (TF) were not significantly correlated with temperature, relative humidity, or CO2 level. However, there was a significant weak correlation between ACC and TF (r = 0.31 [95% CI = 0.07–0.52], p = 0.013). Although significant correlations exist between ACC and IAQ parameters, the relationship is not definitive; the IAQ parameters may affect the microorganisms but are not responsible for the presence of airborne microorganisms. Environmental parameters could be related to the generating source, survival, dispersion, and deposition rate of microorganisms. Future studies should record IAQ parameters and factors such as healthcare worker presence and the activities carried out such as cleaning, sanitizing, and disinfection protocols. Foot traffic would influence both the generation of microorganisms and their deposition rate onto surfaces in the hospital environment. These data would inform models to improve the understanding of the likely concentration of airborne microorganisms and provide an alternative approach for real-time monitoring of the healthcare environment. 相似文献
50.
Louise L. Sousa 《Fuel Processing Technology》2010,91(2):194-196
This paper evaluates the production of methyl esters from castor oil and methanol after neutralization of castor oil with glycerol. The reaction was carried out under atmospheric pressure and ambient temperature in a batch reactor, employing potassium hydroxide as catalyst. Results showed high yield of castor oil into methyl esters after neutralization of castor oil with glycerol. The highest yield observed was of 92.5% after 15 min of reaction. The best operating condition was obtained applying an alcohol to oil molar ratio of 6.0 and 0.5% w/w of catalyst. 相似文献