A new patch antenna with metamaterial cover   总被引：6，自引：0，他引：6  

胡骏阎春生  林青春 《浙江大学学报(A卷英文版)》2006,7(1):89-94

INTRODUCTION Investigation of metamaterials is currently one of the most active frontiers in engineering and physics. Metamaterials are also called backward-wave mate- rials, double-negative materials, or left-handed mate- rials. Left-handed materials were proposed by Vese- lago (1968). The applications of metamaterials are widely spread in many fields (Pendry, 2000; Grbic and Eleftheriades, 2003; Foteinopoulou et al., 2003), such as imaging apparatus, planar light wave circuits, optica…  相似文献   

Students’ approaches to groupwork in a blended course,associations with perceptions of the online environment and academic achievement – when is learning engaged?     

Robert A. Ellis 《Education and Information Technologies》2016,21(5):1095-1112

University teachers provided first year Arts students with hundreds of cinematic images online to analyse as a key part of their predominantly face-to-face undergraduate course. This qualitative study investigates the extent to which the groups engaged in learning involving their analysis of the images and how this was related to their perception of the ICT-mediated environment. Interviews and questionnaires completed by students revealed that the extent of engaged learning was related to the quality of the approach to groupwork reported by the students, the quality of their approach to the analysis of the images and their perceptions of key aspects of the online environment which provided the images. The findings have implications for the design and approach to teaching best suited for students involved in groupwork and the use of ICT resources provided to promote engaged experiences of learning.  相似文献   

Reading Instruction for English Learners in the Middle Grades: a Meta-Analysis     

Colby Hall  Garrett J. Roberts  Eunsoo Cho  Lisa V. McCulley  Megan Carroll  Sharon Vaughn 《Educational Psychology Review》2017,29(4):763-794

This meta-analysis synthesizes the last two decades of experimental and quasi-experimental research on reading instruction across academic contexts (e.g., social studies, science, mathematics, English language arts) for English learners (ELs) in grades 4 through 8, to determine (a) the overall effectiveness of reading instruction for upper elementary and middle school students who are ELs and (b) how the magnitude of the effect varies based on student, instructional, and study characteristics. The analysis included a total of 11 studies with 46 individual effect sizes and yielded a mean effect size of g?=?0.35 across all (i.e., standardized and unstandardized) reading measures, g?=?0.01 across standardized reading measures, and g?=?0.43 across unstandardized reading measures. For all reading, unstandardized reading, all vocabulary, and unstandardized vocabulary measures, results suggest that higher quality studies tended to have smaller effects, and these effects were even more evident for unstandardized measures (i.e., one unit increase in study quality was associated with decreased effects: g?=?0.21, g?=?0.30, g?=?0.24, g?=?0.30, respectively). For all comprehension measures, effects were larger for instruction that included both vocabulary and comprehension (g?=?0.39) than for instruction that focused on vocabulary alone (g?=?0.08). Results suggest the benefit of developing and refining high-impact approaches to reading instruction for ELs that can be delivered across content areas and grades.  相似文献   

Application of neural network in the study of combustion rate of natural gas/diesel dual fuel engine     

严兆大  周重光  苏石川  刘震涛  王希珍 《浙江大学学报(A卷英文版)》2003,4(2):170-174

In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based on forward neural network was built to study the combustion process of the DFE. The effect of the operating parameters on combustion rate was also studied by means of this model. The study showed that the predicted results were good agreement with the experimental data. It was proved that the developed combustion rate model could be used to successfully predict and optimize the combustion process of dual fuel engine. Project supported by National Lab. for Automotive Engine and Safety, Tsinghua University, China  相似文献   

3. Winfried D’Avis. Der informierte Mensch. Sein Weltbild-Sein Gehirn-Sein Computer     

Claus J. Tully  Dirk Baier 《Zeitschrift für Erziehungswissenschaft》2003,6(2):303-304

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The Hidden Curriculum of Domestication     

Juan S. Muñoz  Rosario Ordoñez Jasis  Patricia A. Young  Peter McLaren 《The Urban Review》2004,36(3):169-187

Four ethnically diverse faculty members in the field of education discuss the professional impact and personal affects of introducing critical themes of race, class, gender, and culture within their research and course offerings. Given that the professional outlook for university faculty of color in general, is grim, a willingness to imbue their research and courses with a critical interrogation of prevailing education topics and theories would seem to invite greater personal risk and professional jeopardy. The following dialogue introduces both the mechanisms by which critical faculty in general, and faculty of color in particular, can be conditioned to subordinate their critical impulses and the strategies they use to resist academic cultures of domestication.  相似文献   

Grades degrade group coordination: deteriorated interactions and performance in a cooperative motor task     

Anne-Sophie Hayek  Claudia Toma  Sofia Guidotti  Dominique Oberlé  Fabrizio Butera 《European Journal of Psychology of Education - EJPE》2017,32(1):97-112

At school, pupils often cooperate on common projects and must coordinate their different individual actions. However, grades are pervasively used even in cooperative situations, which make the pupils’ differences in achievement and their relative rank salient and may reduce their inclination to work constructively with others. Thus, we hypothesized that grades would elicit disruptive interactions and reduce performance in a cooperative cognitive-motor task necessitating inter-individual coordination of members. In a study with 5th graders, grades (vs. a neutral concept) were primed at the onset of a cooperative group interaction. Results showed that, although pupils were set to work cooperatively, priming grades (vs. neutral concepts) harmed inter-individual coordination by eliciting more negative dominant behaviours among pupils during interactions, which decreased group performance.  相似文献   

Effects of 3D Printing Project-based Learning on Preservice Elementary Teachers’ Science Attitudes,Science Content Knowledge,and Anxiety About Teaching Science     

Elena Novak  Sonya Wisdom 《Journal of Science Education and Technology》2018,27(5):412-432

3D printing technology is a powerful educational tool that can promote integrative STEM education by connecting engineering, technology, and applications of science concepts. Yet, research on the integration of 3D printing technology in formal educational contexts is extremely limited. This study engaged preservice elementary teachers (N?=?42) in a 3D Printing Science Project that modeled a science experiment in the elementary classroom on why things float or sink using 3D printed boats. The goal was to explore how collaborative 3D printing inquiry-based learning experiences affected preservice teachers’ science teaching self-efficacy beliefs, anxiety toward teaching science, interest in science, perceived competence in K-3 technology and engineering science standards, and science content knowledge. The 3D printing project intervention significantly decreased participants’ science teaching anxiety and improved their science teaching efficacy, science interest, and perceived competence in K-3 technological and engineering design science standards. Moreover, an analysis of students’ project reflections and boat designs provided an insight into their collaborative 3D modeling design experiences. The study makes a contribution to the scarce body of knowledge on how teacher preparation programs can utilize 3D printing technology as a means of preparing prospective teachers to implement the recently adopted engineering and technology standards in K-12 science education.  相似文献   

The madelung constant of the sodium chloride crystal lattice     

Sourav Das 《Resonance》2003,8(10):76-84

An analysis of the Madelung constant of the sodium chloride crystal lattice has been made, in an effort to supplement information available in undergraduate textbooks. A method of approximation of the constant using the personal computer is presented. An erratum to this article is available at .  相似文献   

Sense of Place in Child Care Environments     

Marilyn A. Read 《Early Childhood Education Journal》2007,34(6):387-392

The exterior design of existing preschool environments is evaluated in the context of contemporary writings by architects focusing on creating designs that nurture children’s emotions. Sense of place research is discussed in relation to young children’s experiences. Findings reveal that the majority of sites included in the study incorporated many physical design elements that create a sense of place for children in preschool environments, including small-scale structures, windows, landscaping, natural wall materials, and thresholds. Recommendations for administrators and directors planning and designing a new or remodeled preschool environment include incorporating features that reflect home-like environments with windows, thresholds, and landscaping.  相似文献