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91.
Ordinary and thermal diffusion of moisture in activated alumina are investigated using a new diffusion cell design and scheme of analysis reported earlier. The specific form of the mass flux equation has a pronounced effect on the magnitude of the associated thermal diffusion ratio. In the case of activated alumina-moist air, if a partial pressure gradient is used, then the thermal diffusion term is small if not zero.Free, Knudsen and surface diffusion all play a part in the diffusion through activated alumina. However, surface diffusion makes the major contribution and for this reason the model in this case can be simplified to a two parameter surface model.The activation energy for surface diffusion is constant and is approximately equal to the mean isosteric heat of absorption. In addition, mean pore radius, turtuosity, and other physical constants are computed from the least square fit of experimental data. Furthermore, the model is theoretically consistent over the entire concentration range (0≦ CA ≦ CAsat).A new fact about activated alumina (Grade F1) it that it does not transfer moisture in a nonisothermal condition so long as the partial pressures of moisture on the two sides of the pellet are the same. There appears to be no previous report of this fact in the periodical literature. 相似文献
92.
Tunable pores (TPs) have been used for resistive pulse sensing of 1 μm superparamagnetic beads, both dispersed and within a magnetic field. Upon application of this field, magnetic supraparticle structures (SPSs) were observed. Onset of aggregation was most effectively indicated by an increase in the mean event magnitude, with data collected using an automated thresholding method. Simulations enabled discrimination between resistive pulses caused by dimers and individual particles. Distinct but time-correlated peaks were often observed, suggesting that SPSs became separated in pressure-driven flow focused at the pore constriction. The distinct properties of magnetophoretic and pressure-driven transport mechanisms can explain variations in the event rate when particles move through an asymmetric pore in either direction, with or without a magnetic field applied. Use of TPs for resistive pulse sensing holds potential for efficient, versatile analysis and measurement of nano- and microparticles, while magnetic beads and particle aggregation play important roles in many prospective biosensing applications. 相似文献
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The thesis of this study is to propose an extended methodology for laboratory based Information Retrieval evaluation under incomplete relevance assessments. This new methodology aims to identify potential uncertainty during system comparison that may result from incompleteness. The adoption of this methodology is advantageous, because the detection of epistemic uncertainty – the amount of knowledge (or ignorance) we have about the estimate of a system’s performance – during the evaluation process can guide and direct researchers when evaluating new systems over existing and future test collections. Across a series of experiments we demonstrate how this methodology can lead towards a finer grained analysis of systems. In particular, we show through experimentation how the current practice in Information Retrieval evaluation of using a measurement depth larger than the pooling depth increases uncertainty during system comparison. 相似文献
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97.
Drawing from the Deweyan theory of experience (1934, 1938), the goal of teaching and learning for transformative, aesthetic
experience is contrasted against teaching and learning from a cognitive, rational framework. A quasi-experimental design was
used to investigate teaching and learning of fifth grade science from each perspective across an entire school year including
three major units of instruction. Detailed comparisons of teaching are given and pre and post measures of interest in learning
science, science identity affiliation, and efficacy beliefs are investigated. Tests of conceptual understanding before, after,
and one month after instruction reveal teaching for transformative, aesthetic experience fosters more, and more enduring,
learning of science concepts. Investigations of transfer also suggest students learning for transformative, aesthetic experiences
learn to see the world differently and find more interest and excitement in the world outside of school. 相似文献
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This study, situated in a multilingual, English-medium educational context, draws on theory from mathematics and language education to capture teachers’ perspectives on the place of language in their mathematics pedagogy. The benchmark study explored this topic through surveying and interviewing teachers. Additionally, it sought to relate teachers’ views to their practice by focusing on observing three teachers’ mathematics lessons at primary one, three, and five. Findings are that mathematics teachers placed importance on teaching language, being specifically concerned with language as input and comprehension. They taught vocabulary and reading skills in supportive ways explicitly yet differently at the three grade levels. Particularly at the lower levels, teachers contextualised language in the concrete examples employed for mathematics teaching. At all three levels, prominence was given to teaching pupils how to read word problems as well as how to solve them. However, at primary three, a tension was observed between the two aims of teaching mathematical vocabulary and teaching the reading skills for word problems. This paper illustrates the tension and discusses its possible causes. 相似文献
100.
Karen L. Bierman Rebecca M. Sanford DeRousie Brenda Heinrichs Celene E. Domitrovich Mark T. Greenberg Sukhdeep Gill 《Early education and development》2013,24(8):1194-1213
Research Findings: Recent research has validated the power of evidence-based preschool interventions to improve teaching quality and promote child school readiness when implemented in the context of research trials. However, very rarely are follow-up assessments conducted with teachers in order to evaluate the maintenance of improved teaching quality or sustained use of evidence-based curriculum components after the intervention trial. In the current study, we collected follow-up assessments of teachers 1 year after their involvement in the REDI (REsearch-based, Developmentally Informed) research trial to evaluate the extent to which intervention teachers continued to implement the REDI curriculum components with high quality and to explore possible preintervention predictors of sustained implementation. In addition, we conducted classroom observations to determine whether general improvements in the teaching quality of intervention teachers (relative to control group teachers) were sustained. Results indicated sustained high-quality implementation of some curriculum components (the Promoting Alternative THinking Strategies curriculum) but decreased implementation of other components (the language/literacy components). Sustained intervention effects were evident on most aspects of general teaching quality targeted by the intervention. Practice or Policy: Implications for practice and policy are discussed. 相似文献