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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
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Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium resistant to all existing penicillin and lactam-based antimicrobial drugs and, therefore, has become one of the most prevalent antibiotic-resistant pathogens found in hospitals. The multi-drug resistant characteristics of MRSA make it challenging to clinically treat infected patients. Therefore, early diagnosis of MRSA has become a public-health priority worldwide. Conventionally, cell-culture based methodology and microscopic identification are commonly used for MRSA detection. However, they are relatively time-consuming and labor-intensive. Recently, molecular diagnosis based on nucleic acid amplification techniques, such as polymerase chain reaction (PCR), has been widely investigated for the rapid detection of MRSA. However, genomic DNA of both live and dead pathogens can be distinguished by conventional PCR. These results thus could not provide sufficient confirmation of an active infection for clinicians. In this study, live MRSA was rapidly detected by using a new integrated microfluidic system. The microfluidic system has been demonstrated to have 100% specificity to detect live MRSA with S. aureus and other pathogens commonly found in hospitals. The experimental results showed that the limit of detection for live MRSA from biosamples was approximately 102 CFU/μl. In addition, the entire diagnostic protocol, from sample pre-treatment to fluorescence observation, can be automatically completed within 2.5 h. Consequently, this microfluidic system may be a powerful tool for the rapid molecular diagnosis of live MRSA. 相似文献
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Wu Chih-Hung Tzeng Yi-Lin Huang Yueh-Min 《Educational technology research and development : ETR & D》2020,68(5):2215-2237
Educational technology research and development - This study investigated and compared the effectiveness of both digital game-based learning (DGBL) and static e-learning material for Newton’s... 相似文献
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Although the practice of building brand equity in the context of professional sport teams is popular, the formation of sport team brand equity in the sport marketing literature is still relatively unknown and incompletely understood. In this study, the authors propose a dual-identification model to examine the formation of sport team brand equity in an Asia-based professional team sport setting. Baseball fans (N = 548) of the Chinese Professional Baseball League (CPBL) in Taiwan participated in the self-administered survey. A Partial Least Squares Structural Equation Model analysis revealed that marketplace characteristics (including group experience, salient experience, team history, and fan rituals) and brand-identified-related factors (including self-congruity and team brand prestige) were significantly related to identification with sport team and identification with sport team brand, respectively. In turn, both identification with sport team and identification with sport team brand were significant predictors of sport team brand equity. These findings highlight the importance of studying a dual-identification model in order to understand how sport team brand equity forms and suggest implications for sport team managers. 相似文献
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Gwo-Jen Hwang Chih-Hung Chen 《British journal of educational technology : journal of the Council for Educational Technology》2017,48(4):950-971
In this paper, an inquiry-based ubiquitous gaming approach was proposed. The objective of the study was to enhance students’ performances in in-field learning activities. To show the advantages of the approach, an experiment was carried out to assess the effects of it on students’ learning achievement, motivation, critical thinking, and problem solving. Furthermore, the students’ behavioral patterns were investigated via content and sequential analysis methods. The experimental outcomes show that the approach promoted students’ performances of learning achievement and intrinsic motivation; moreover, the students’ perceptions of their problem solving and critical thinking were significantly promoted as well. The learning behavior analysis further show that the designated approach stimulated the participants to actively engage in field observation, comparison, and data searching in the context ware in-field learning activity. 相似文献
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Educational technology research and development - Although a great deal of research has evidenced the effects of proper instructional design on multimedia learning, most has focused on the... 相似文献
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Ah-Fur Lai Chih-Hung Chen Gon-Yi Lee 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(1):232-247
Reading has been regarded as a medium for learning science, revealing the importance of enhancing learners’ reading competence in science education. The critical features of science texts are their multiple representations, such as text and visual elements, which assist the representation of science concepts. A multimedia learning environment can present relevant materials in various formats and help students to process the materials in meaningful ways, for example, by integrating learning materials with relevant prior concepts, and organizing them into a consistent and coherent cognitive structure. However, some issues with multimedia instructional design have been proposed, such as students’ cognitive load and learning motivations. In this study, an augmented reality-based science learning system was developed based on the contiguity principle of multimedia learning in order to promote students’ science learning. Moreover, an experiment was conducted on a natural science course in an elementary school to assess the effectiveness of the implemented system on students’ learning. The experimental results display that the students learning with this approach found made significant gains in their learning achievements and motivations compared to those learning science with conventional multimedia science learning; moreover, their perceptions of extraneous cognitive load were significantly reduced during the learning activity. 相似文献
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Augmented reality (AR) offers potential advantages for intensifying environmental context awareness and augmenting students’ experiences in real-world environments by dynamically overlapping digital materials with a real-world environment. However, some challenges to AR learning environments have been described, such as participants’ cognitive overload and the ways to provide assistance in constructing the presented learning materials. In this study, a mindtool-based AR learning system was developed, based on the repertory grid method and the contiguity principle of multimedia learning, for assisting students in constructing their knowledge in a natural science course. Furthermore, an experiment was carried out on an elementary school natural science course to compare the influences of this method with those of the conventional AR learning system on students’ learning effectiveness. The experimental results show that the designated approach effectively promoted the students’ learning achievements, and no significant difference existed between the mindtool-based AR learning system and the conventional AR learning system in terms of students’ cognition load and satisfaction degree; moreover, both the experimental group and the control group perceived low cognition load during the learning activity and rated their own AR learning systems as being highly satisfactory. 相似文献
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