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991.
992.
The Effects of a Student Sampling Plan on Estimates of the Standard Errors for Student Passing Rates
Examined in this study were three procedures for estimating the standard errors of school passing rates using a generalizability theory model. Also examined was how these procedures behaved for student samples that differed in size. The procedures differed in terms of their assumptions about the populations from which students were sampled, and it was found that student sample size generally had a notable effect on the size of the standard error estimates they produced. Also the three procedures produced markedly different standard error estimates when student sample size was small. 相似文献
993.
The pressure to reduce solar energy costs encourages efforts to reduce the thickness of silicon wafers. Thus, the cell bowing problem associated with the use of thin wafers has become increasingly important, as it can lead to the cracking of cells and thus to high yield losses. In this paper, a systematic approach for simulating the cell bowing induced by the firing process is presented. This approach consists of three processes: (1) the material properties are determined using a nanoidentation test; (2) the thicknesses of aluminum (Al) paste and silver (Ag) busbars and fingers are measured using scanning electron microscopy; (3) non-linear finite element analysis (FEA) is used for simulating the cell bowing induced by the firing process. As a result, the bowing obtained using FEA simulation agrees better with the experimental data than that using the bowing calculations suggested in literature. In addition, the total in-plane residual stress state in the wafer/cell due to the firing process can be determined using the FEA simulation. A detailed analysis of the firing-induced stress state in single crystalline silicon (sc-Si), cast, and edge-defined film-fed growth (EFG) multi-crystalline silicon wafers of different thicknesses is presented. Based on this analysis, a simple residual stress calculation is developed to estimate the maximum in-plane principal stress in the wafers. It is also proposed that the metallization pattern, Ag busbars and fingers screen printed on the front of a solar cell, can be designed using this approach. A practical case of a 3-busbar Si solar cell is presented. 相似文献
994.
995.
John M. Reveles Gregory J. Kelly Richard P. Durán 《Cultural Studies of Science Education》2007,1(3):467-495
This ethnographic study of a third grade classroom examined elementary school science learning as a sociocultural accomplishment.
The research focused on how a teacher helped his students acquire psychological tools for learning to think and engage in
scientific practices as locally defined. Analyses of classroom discourse examined both how the teacher used mediational strategies
to frame disciplinary knowledge in science as well as how students internalized and appropriated ways of knowing in science.
The study documented and analyzed how students came to appropriate scientific knowledge as their own in an ongoing manner
tied to their identities as student scientists. Implications for sociocultural theory in science education research are discussed.
John Reveles is an assistant professor in the Elementary Education Department at California State University, Northridge. He received
his Ph.D. from the University of California, Santa Barbara in 2005. Before pursuing his Ph.D., he worked as a bilingual elementary
school teacher for 3 years. His research focuses on the development of scientific literacy in elementary school settings;
sociocultural influences on students' academic identity; equity of access issues in science education; qualitative and quantitative
research methods. Within the Michael D. Eisner College of Education, he teaches elementary science curriculum methods courses,
graduate science education seminars, and graduate research courses.
Gregory Kelly is a professor of science education at Penn State University. He is a former Peace Corps Volunteer and physics teacher. He
received his Ph.D. from Cornell in 1994. His research focuses on classroom discourse, epistemology, and science learning.
This work has been supported by grants from Spencer Foundation, National Science Foundation, and the National Academy of Education.
He teaches courses concerning the uses of history, philosophy, sociology of science in science teaching and teaching and learning
science in secondary schools. He is editor of the journal Science Education.
Richard Durán is a Professor in the Gevirtz Graduate School of Education, University of California, Santa Barbara. His research and publications
have been in the areas of literacy and assessment of English Language Learners and Latino students. He has also conducted
research on after school computer clubs, technology and learning as part of the international UC Links Network. With support
from the Kellogg Foundation, he is implementing and investigating community and family-centered intervention programs serving
the educational progress of Latino students in the middle and high school grades. 相似文献
996.
997.
The Development of Everyday Mathematics in Brazilian Children with Limited Formal Education 总被引:1,自引:0,他引:1
Steven R. Guberman 《Child development》1996,67(4):1609-1623
The sociocultural context in which children acquire and use everyday mathematics was studied in Brazilian shantytown communities. Children's developing mathematical abilities and use of currency in solving commercial problems were investigated. Interviews with the parents of 105 children from 4 to 14 years of age indicated that, when sent to make purchases at local stands, the problems entailed in the responsibilities parents assigned to children involved greater arithmetical complexity with increasing age. Children's accuracy and strategy use on arithmetic tasks similar to the problems encountered in commercial transactions revealed: ( a ) many children used currency to aid their problem solving; ( b ) with increasing age, currency use declined; and ( c ) children's currency use progressed from global estimates to the mental decomposition and manipulation of currency values. The mathematical complexity of children's commercial transactions correlated significantly with their mathematics performance even when age, grade in school, and years of schooling were statistically controlled The results provide evidence that by adjusting the mathematical complexity of children's commercial transactions, parents facilitate connections between children's developing competence and their everyday activities. 相似文献
998.
Maria Gouveia-Pereira Jorge Vala Augusto Palmonari Monica Rubini 《European Journal of Psychology of Education - EJPE》2003,18(3):309-325
This study analysis the relationship between perceptions of the justice of teacher’ behaviour and (a) the legitimation of school authority and (b) the legitimation of institutional authorities outside school. 448 adolescent students participated in the study. In questionnaire participants were asked about (a) perceptions of the justice of teachers’ behaviour; (b) evaluation of the school experience; and (c) evaluation of institutional authorities. Results show that the evaluation of the justice of teacher behaviour, in particular relational and procedural justice, have an impact on the legitimation of the authority of teachers and on the evaluation of institutional authorities outside school. Results also show that the legitimacy granted to teachers is a mediator variable between perceptions of justice in school and evaluation of authorities outside school. These results are discussed in the context of the studies on the relationship between school experience and adolescents attitudes towards authorities, and in the framework of the “Relational Model of Authority” and of the “Group Value Model”. 相似文献
999.
Ng Pak Tee 《Educational Research for Policy and Practice》2004,3(3):183-198
Schools in Singapore are now tasked to develop the spirit of innovation and enterprise in their students. This is in line with the national vision of ‘Thinking Schools, Learning Nation’. This policy initiative, which began in 2004, is set to change the fundamental nature of education in Singapore. This article discusses the innovation and enterprise (I&E) initiative, its major implications for schools in Singapore and the areas still to be addressed in the implementation of the policy. In particular, the article discusses the issues of teachers and school leaders as role models of I&E, I&E as an organic part of school business, the influence of the wider societal culture and values system, and the measurement of success of I&E. The challenge for schools is to go beyond the form of the initiative to bring real substantial and sustainable change through this movement. 相似文献
1000.
Learning science through writing: associations with prior conceptions of writing and perceptions of a writing program 总被引:1,自引:0,他引:1
Students in a large undergraduate biology course were expected to write a scientific report as a key part of their course design. This study investigates the quality of learning arising from the writing experience and how it relates to the quality of students’ preconceptions of learning through writing and their perceptions of their writing program that led to their report. Closed‐ended questionnaires investigating student conceptions and perceptions of writing, and approaches to writing, were completed by 121 students. Significant associations were found amongst qualitatively different prior and post conceptions of writing, approaches to writing and achievement. The results of the analyses suggest that the effective support of student experiences of writing reports requires teachers to be aware of the type of conceptions that students bring to their course and the perceptions they hold about the purpose of the writing program in which they are engaged. 相似文献