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31.
目的:设计制造低温的催化氢气燃烧器,并对其进行相关功能性测试。创新点:成功设计并制造出一个集成流量分配器的催化低温氢气燃烧器。方法:1.基于树状分叉方法,设计燃烧器的流量分配器,均匀分配气体到催化表面,并利用熔融沉积成型技术制备原型样机。2.基于测试结果,利用选择性激光熔化技术对燃烧器进行最优化设计。3.对设计的催化燃烧器的相关功能进行验证。结论:1.设计的低温催化燃烧器与传统的非催化燃烧器相比具有很多优势,尤其是实现了无焰均匀低温(约200°C)的产热;这一技术有望运用于化工领域的增材制造。2.本文不但用选择性激光熔融技术制备了最终产品,而且利用了熔融沉积成型技术进行快速的样机制备。3.催化剂多孔载体的调控和催化剂的负载方式研究有望进一步提升燃烧器的综合性能。 相似文献
32.
Hendrik Lohse-Bossenz Olga Kunina-Habenicht Mareike Kunter 《European Journal of Psychology of Education - EJPE》2013,28(4):1543-1565
The aim of this study is to identify psychological topics within the areas of learning, development, and assessment that are especially important for teachers and should be included in the university teacher education curriculum. Based on the observation that teacher educators in psychology often face the challenge of having to select certain topics from a large body of possible content, at the risk of causing large variation of knowledge between teachers, we asked 48 experts from different fields of teacher education (psychologists, non-psychologists at university, and educators from the induction phase) to evaluate psychological topics with respect to their importance to teaching. In the following two rounds (Delphi method), experts selected topics which they felt should be taught at university. Although differences existed at the beginning, a ranking of topics was obtained. Further, we explored the way experts with different backgrounds achieved consensus to support the validity and acceptance of the results. Concluding, we discuss the usefulness of the results with a focus on the acquisition of psychological knowledge for teachers and to foster the position of educational psychology within teacher education. 相似文献
33.
Angel Gabriel Lucas-Cuevas Jennifer Baltich Hendrik Enders Sandro Nigg Benno Nigg 《Journal of sports sciences》2016,34(9):803-810
Muscle weakness is considered a risk factor for ankle injury. Balance training and barefoot running have been used in an attempt to strengthen the muscles crossing the ankle. It is expected that training tasks that successfully strengthen the ankle would elicit increased muscular activity. However, it is unknown how an individual's ankle strength will influence the muscle activity used during a given task. Twenty-six participants performed dynamic (shod, barefoot running) and static tasks (squat on ground, squat on ®Bosu Ball) believed to strengthen the muscles surrounding the ankle. Electromyographic signals of the tibialis anterior, peroneus longus, gastrocnemius lateralis (GL) and gastrocnemius medialis (GM) were recorded and analysed using a non-linearly scaled wavelet analysis. Participants were divided into a strong group and a weak group according to their isometric plantar-flexion torque. The weak group required more relative GL and GM muscle activity during each training task compared to the strong group. No difference was observed between shod and barefoot running. There was a significant effect of training task on muscle activation level for the weak group. Differences in ankle strength had a significant impact on muscle activation. 相似文献
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35.
Hendrik Lohse-Bossenz Doris Holzberger Olga Kunina-Habenicht Tina Seidel Mareike Kunter 《Zeitschrift für Erziehungswissenschaft》2018,21(5):991-1019
General pedagogical knowledge (GK) as part of teachers’ professional knowledge has been receiving increasing attention in empirical research. Current results are based on the assumption that GK is conceptualized and acquired during teacher education independent from the subjects being studied. Therefore, we examine whether GK can be measured comparably across subjects and whether differences exist among teachers from different subject specializations concerning their level of GK. Results from 2616 preservice teachers starting their induction phase indicate that knowledge can be invariantly measured across three subject groups, i.?e., science, languages/humanities and a combination of these subjects. However, teachers vary systematically depending on their subject specializations (controlling for gender, language, grade point average, and school track). Science teachers achieve higher test scores for diagnostic/evaluation and lower scores in fields more removed from direct instruction (e.?g., theory of education). There are no differences concerning knowledge directly related to instruction (e.?g., learning/development). Results are discussed with reference to subject-related factors of socialisation, selection and development in the profession. 相似文献
36.
Hendrik Dubbe Elena Holl Adriaan Spierings Konrad Wegener Ulrich Nieken 《浙江大学学报(A卷英文版)》2018,19(10):735-745
Examples of the use of additive manufacturing and rapid prototyping in a range of applications are of great interest in order to emphasize their role in development and production technology. In this study, a catalytic low temperature burner for H2 on a lab scale with an integrated flow distributor was designed, manufactured, and tested for functionality. Based on a theoretical approach, a flow distributor for the burner was designed and a prototype was built using fused deposition modeling (FDM). Based on test results, an optimized version of the burner was then designed and manufactured using selective laser melting (SLM). The functionality of the designed catalytic burner was proven. Several advantages were found in comparison to conventional non-catalytic burners. In particular, flameless uniform low temperature heat generation with temperatures of about 200 °C could be realized. This contribution highlights the potential of additive manufacturing in chemical engineering. Not only was the final product built using SLM, but also during the development process, FDM was used for rapid prototyping. 相似文献
37.
Hendrik Snyders 《国际体育史杂志》2018,35(10):1029-1059
AbstractIn the period from1976 to1990 during the international campaign against apartheid, some affiliate members of the USA Rugby Football Union, went out of their way to establish and maintain a strong relationship with the South African Rugby Football Board and its successor, the South African Rugby Board. Over the course of six reciprocal tours, they ignored the campaigns of the worldwide anti-apartheid movement and the British Commonwealth. In their dogged pursuit of a sporting relationship with a key South African cultural institution that buttressed apartheid in a sport that, at best, enjoyed minority status in the United States, they defied both their own national federation and the American Olympic Committee. By 1990 as the international campaign against apartheid became a truly worldwide affair, US–South Africa rugby relations were suspended in line with larger political developments both within and outside of the country. This essay, beyond mapping the trials and tribulations of that relationship, also foregrounds a largely hidden history in order to fill the existing gap in the official sporting histories of both the United States and South Africa. 相似文献
38.
Hendrik Sonnabend 《Journal of Cultural Economics》2016,40(4):529-545
Unlike Kahneman et al. (Am Econ Rev 76(4):728–741, 1986) iconic snow shovel, live music is a performance good that fans attach a particular value to. Hence, an artist’s pricing decision might differ from standard rent-seeking behavior. In this paper, I propose a model that incorporates fairness concerns into the pricing decision for concert tickets. The hypotheses derived from this model are tested on data from the German club concert industry. The results are consistent with the model: Although (1) price dispersion is the dominant pricing strategy in the club concert industry and artists prefer to perform on a Friday or Saturday night, (2) artists do not set higher prices on the weekend. These results are consistent with fairness constraints, but are difficult to explain within a standard profit maximization framework. As a third result, (3) the data reveal that ticket prices are positively correlated with a city’s number of inhabitants . 相似文献
39.
Human vs. Computer Diagnosis of Students’ Natural Selection Knowledge: Testing the Efficacy of Text Analytic Software 总被引：2，自引：2，他引：0
Our study examines the efficacy of Computer Assisted Scoring (CAS) of open-response text relative to expert human scoring
within the complex domain of evolutionary biology. Specifically, we explored whether CAS can diagnose the explanatory elements
(or Key Concepts) that comprise undergraduate students’ explanatory models of natural selection with equal fidelity as expert
human scorers in a sample of >1,000 essays. We used SPSS Text Analysis 3.0 to perform our CAS and measure Kappa values (inter-rater
reliability) of KC detection (i.e., computer–human rating correspondence). Our first analysis indicated that the text analysis
functions (or extraction rules) developed and deployed in SPSSTA to extract individual Key Concepts (KCs) from three different
items differing in several surface features (e.g., taxon, trait, type of evolutionary change) produced “substantial” (Kappa
0.61–0.80) or “almost perfect” (0.81–1.00) agreement. The second analysis explored the measurement of human–computer correspondence
for KC diversity (the number of different accurate knowledge elements) in the combined sample of all 827 essays. Here we found
outstanding correspondence; extraction rules generated using one prompt type are broadly applicable to other evolutionary
scenarios (e.g., bacterial resistance, cheetah running speed, etc.). This result is encouraging, as it suggests that the development
of new item sets may not necessitate the development of new text analysis rules. Overall, our findings suggest that CAS tools
such as SPSS Text Analysis may compensate for some of the intrinsic limitations of currently used multiple-choice Concept
Inventories designed to measure student knowledge of natural selection. 相似文献
40.
Dr. Olga Kunina-Habenicht Hendrik Lohse-Bossenz Prof. Dr. Mareike Kunter Theresa Dicke Doris F?rster Jill G??ling Franziska Schulze-Stocker Annett Schmeck Jürgen Baumert Detlev Leutner Ewald Terhart 《Zeitschrift für Erziehungswissenschaft》2012,15(4):649-682
In reviews of university teacher training, the parts of the curriculum based on educational science are often criticized as missing practical relevance and being non-cumulative. At the same time, uncertainty exists regarding which educational science based content is important for teacher candidates. The objective of the Delphi study presented here was the identification of core educational science content in university training. To this aim, a survey was carried out amongst 49 experts from different subject areas and phases of teacher training in three rounds using a standardized questionnaire. In the first round, 213 topics were specified, which were then assessed by experts regarding their importance for various aspects of the teaching profession. In the second and third rounds, which had the objective of reducing the number of topics, the experts chose a limited number of topics based on their relevance for university teacher training and for the practical success of teaching itself. The results show that the original list was comprehensive and that there is a consensus among most of the experts on their respective importance for teaching training. 相似文献