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861.
In this study, we used a simple impregnation method to prepare Fe–Ce–O x catalysts and tested them regarding their low-temperature (200–300 °C) selective catalytic reduction (SCR) of NO using NH3. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO2/H2O resistance of the catalysts. The results showed that the FeCe(1:6)O x (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O x catalyst had the highest NO conversion with an activity of 94–99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h?1. The NO conversion for the FeCe(1:6)O x catalyst also reached 80–98% between 200 and 300 °C at a space velocity of 204,000 h?1. In addition, the FeCe(1:6)O x catalyst demonstrated good stability in a 10-h SCR reaction at 200–300 °C. Even in the presence of SO2 and H2O, the FeCe(1:6)O x catalyst exhibited good SCR performance. 相似文献
862.
The term noise is used to describe fluctuations about the mean deterministic stationary value of a physical quantity. It is
now being increasingly realised that noise is an important ingredient to bring order in dynamical processes. Though it appears
counterintuitive, noise seems to help in directing transport processes in biological systems at the molecular level. In Part
2 of the article, we discuss some more examples of noise assisted directed motion. 相似文献
863.
The objective of this study was to assess the impact on phonological skills of a training program that was intended to lead preschool children to move from prephonetic spellings to early phonemic spellings. The participants were 30 preschool children who were divided into two groups (experimental and control groups) that were equivalent in terms of the children's intelligence, the number of letters with which they were familiar and the nature of their invented spelling. The intervention proved effective, inasmuch as the children in the experimental group moved to early phonemic spellings, whereas those in the control group did not. This conceptual evolution entailed enhanced performance in phonemic classification, segmentation and deletion tests, in which the children in the experimental group displayed a degree of progress which differed significantly from that achieved by the members of the control group. 相似文献
864.
Phenol degradation in photochemically enhanced Fenton process was investigated in this work. UV-VIS spectra of phenol degradation showed the difference between photo-Fenton process and UV/H2O2, which is a typical hydroxyl radical process. A possible pathway diagram for phenol degradation in photo-Fenton process was proposed, and a mathematical model for chemical oxygen demand (COD) removal was developed. Operating parameters such as dosage of H2O2 and ferrous ions, pH, suitable carrier gas were found to impact the removal of COD significantly. The results and analysis of kinetic parameters calculated from the kinetic model showed that complex degradation of phenol was the main pathway for removal of COD; while hydroxyl radicals acted weakly in the photo-Fenton degradation of phenol. 相似文献
865.
Meredith Mountford 《Innovative Higher Education》2005,30(3):213-227
This article describes strategies for redesigning the University of Missouri's Statewide Cooperative Ed.D. Cohort Program
in educational leadership. Results had suggested a need to redesign aspects of the program in order to achieve higher levels
of cognitive learning outcomes inclusive of transformational learning. To help meet this objective, the areas targeted for
redesign were the curriculum as it relates to issues of diversity and ethics, instruction as it relates to group dynamics
and cohort models, and increased time and a forum for students to reflect on their leadership practices. This forum also allowed
faculty to monitor and assess the transformational learning outcomes of their students. This article is meant to assist others
who are interested in fostering higher levels of transformational learning outcomes within their programs.
Meredith L. Mountford holds a Bachelor of Science degree from Illinois State University, a Master of Science degree in educational
administration from Northern Illinois University and a Philosophy of Science degree in educational administration from the
University of Wisconsin—Madison. She is an Assistant Professor and has served as Director for the Statewide Cooperative Ed.D.
Cohort Program in educational leadership at the University of Missouri—Columbia. 相似文献
866.
867.
This study investigated patterns of college attendance using data from a nationwide and contemporary sample of 2112 rural youth. We found that more than half of rural youth attended two-year institutions at some point during their college career and about a fourth initially enrolled in a two-year college before enrolling in a four-year college. Results also revealed that parental education, college preparatory track and preparation experiences, and teacher expectations predicted students’ college attendance patterns. Our findings point to the importance of two-year colleges and highlight the influence of family characteristics and students’ schooling experiences in the postsecondary trajectories of rural youth. 相似文献
868.
The relation of parenting style to adolescent school performance 总被引:21,自引:0,他引:21
S M Dornbusch P L Ritter P H Leiderman D F Roberts M J Fraleigh 《Child development》1987,58(5):1244-1257
This article develops and tests a reformation of Baumrind's typology of authoritarian, permissive, and authoritative parenting styles in the context of adolescent school performance. Using a large and diverse sample of San Francisco Bay Area high school students (N = 7,836), we found that both authoritarian and permissive parenting styles were negatively associated with grades, and authoritative parenting was positively associated with grades. Parenting styles generally showed the expected relation to grades across gender, age, parental education, ethnic, and family structure categories. Authoritarian parenting tended to have a stronger association with grades than did the other 2 parenting styles, except among Hispanic males. The full typology best predicted grades among white students. Pure authoritative families (high on authoritative but not high on the other 2 indices) had the highest mean grades, while inconsistent families that combine authoritarian parenting with other parenting styles had the lowest grades. 相似文献
869.
M S Lilly 《Exceptional children》1971,37(5):341-347
870.
Over 25 years ago, Brown and Duguid (Organisation Science, 2(1), 40–57, 1991) highlighted the differences between the way organisations formally describe and delineate jobs and the actual practices of their employees. This paper combines ideas from their seminal contribution with theories of ‘job crafting’ and identity to examine the agentic behaviour of employees in low-grade, ‘dirty work’ as they utilise their expertise and practices to (re)frame their occupational identities and challenge their prescribed job boundaries. The evidence for the paper comes from a qualitative study of hospital porters in the UK’s National Health Service. It argues that this combined theoretical approach provides a potential research and employment framework to challenge the abstracted and stereotypical conceptions of the expertise related to low-grade jobs. 相似文献