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51.
A clinical task-based interview can be seen as a situation where the interviewer–interviewee interaction on a task is regulated
by a system of explicit and implicit norms, values, and rules. This paper describes how documenting and mapping triadic interaction
among the interviewer, the interviewee, and the knowledge negotiated can be used to increase procedural replicability of the
interview and accuracy of drawn conclusions about the interviewee’s thinking process. Excerpts from interviews with 25 inservice
mathematics teachers working on a task to make up a problem whose solution requires division of two fractions are discussed.
The excerpts illustrate the relationship between methodological decisions taken by the interviewer during the interview and
the applicability of the interview output to the research questions. A divergent analysis of the interviews with these teachers,
which spanned over two years and were conducted by four interviewers, is used to offer a framework for analyzing data collected
in clinical task-based interviews. 相似文献
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53.
1IntroductionBackground subtraction methods are extensively ex-ploited for moving object detection in videos in manyapplications ,such as traffic monitoring[1],human mo-tion capture[2]and video surveillance[3]. The centralidea behind such methods is to segment foreground ini mage sequences taken from a fixed camera by com-paring each newframe to a model of the scene back-ground . Therefore , correctly and efficiently modelingand updating the background model is one of the mostchallenging aspec… 相似文献
54.
Malcolm Thorburn 《课程研究杂志》2017,49(5):722-741
Curriculum for Excellence in Scotland outlines a policy vision of a more progressive, integrated and holistic form of education; a commitment which contains an obligation for health and well-being (HWB) to be a responsibility of all teachers. A critical policy analysis approach was utilized in order to review school-level progress in different stages of policy development, i.e. policy formulation, legitimation, implementation and evaluation. Evidence was collected through 15 semi-structured interviews with head teachers, teacher education academics and staff with national and local authority quality improvement remits. Questions focused on: aims and curriculum goals; school culture; learning and teaching; partnership relationships and evaluations of practice. Findings suggest a high degree of support for curriculum aims, however, there were often problems communicating policy expectations (policy formulation). Thus, despite impressive examples of innovative practice in relation to school ethos, wider achievement and pupils’ broader general education (policy legitimation), there were also examples of HWB being constrained by senior school examinations and the backwash effect this had on curriculum planning and engagement with interdisciplinary learning approaches (policy implementation/evaluation). These findings have implications in terms of policy to practice coherence as well as highlighting the need for further more specific research evaluations. 相似文献
55.
Malcolm Crick 《Distance Education》1980,1(2):127-141
This article argues for the development of group intervention techniques to improve the efficacy of course teams in the preparation of distance education materials. A review of recent commentaries on course teams is presented along with an initial selection and discussion of course team issues. These are presented in the refreshingly frank domestic context of actual interactions. The irritations generated by these will be familiar to practitioners. The author concludes with a series of recommendations to enrich the quality of course team life and output. It is hoped that this provocative analysis of the course team method of producing distance education materials will generate a lively response. 相似文献
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Takashi Sagawa 《浙江大学学报(A卷英文版)》2018,19(1):80-85
Composite materials of Fe/Al2O3, which consist of small particles of iron supported by thermally stable alumina even at 500–700 °C, have been widely used in the water-gas shift reaction for natural gas reforming. Therefore, Fe/Al2O3 is one of the promising candidates for re-transformation of exhausted CO2 into fuels such as alcohols and hydrocarbons. The development of a CO2 reforming system using the composite materials of Fe/Al2O3 through CO2 reduction to CO, dissociation of water into hydrogen, and methanol synthesis has been investigated. It was found that dry and steam (i.e. wet) reforming of CO2 produced almost the same amount of CO. At a temperature above 500 °C, maximal and saturated yields of CO and H2 from CO2 and water were obtained. However, this CO2 reforming system requires higher-pressure conditions from several tens to hundreds standard atmospheric pressure in order to achieve high yield and selectivity for methanol production. In this study we developed the modified CO2 reforming system by the utilization of Ni and/or Cu instead of Fe in order to obtain other types of useful products such as CO, CH4, and carbon, more efficiently and selectively under atmospheric pressure. When Ni or Cu was used, conversion of CO2 was reduced to 76%, while 9% of methane was detected in the case of Ni. On the other hand, though the CO2 conversion reduced half of the Fe, the selectivity of CO from CO2 increased to 95% in the case of Cu. 相似文献
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60.
Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system 总被引:2,自引:0,他引:2
Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using
advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The
working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model.
Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as
poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was
conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera.
The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good
agreement with the numerical result.
Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for
Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097) 相似文献