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111.
Education and Information Technologies - Solving word problems involving 'Time' is an important skill but poor mastery of the skill among elementary students has often been reported in the...  相似文献   
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Abstract Using a liquid approach, the authors analyze the intercultural discourse of Taiwanese students who had taken part in a short term exchange program with a Malaysian university. The four participants were graduating in Mandarin Chinese in their home institution and were following a Chinese program in multilingual Malaysia. Data were collected through focus groups held in Mandarin Chinese and focused on their experience in the host country. The authors analyze how participants talk about themselves, Malaysians, and their adaptation to the host country. The processes of essentialization and othering that occur and put in contrast the host and the home contexts are similar to those held in Asia-to-Europe mobility and very far from an “interculturality without culture” (Dervin, 2010). If we focus on the construction of discourses, this Asia-to-Asia mobility forces us to relativize the opposition of cultures as an explanation for difficulties encountered by mobile students.  相似文献   
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Solar energy is a natural resource which can be harnessed to provide clean electricity for hydrogen production systems. However, this technology is not widely used because of control issues, particularly for hydrogen refuelling stations. At present, direct or DC-DC converter couplings are the most common system configurations for hydrogen refuelling stations. However, these system configurations are costly and suffer from gas shortage at hydrogen refuelling stations. Furthermore, the hydrogen produced by such system configurations varies considerably depending on the levels of solar radiation. In order to address these issues, a new system configuration is proposed, incorporating the feedback signal of the storage level in the control system. The photo- voltaic (PV) system, electrolyzer, and storage tank are integrated with a fuzzy logic controller (FLC) to determine the backup current compensation for electrolyzer operation in order to obtain the minimum power required for hydrogen production. The proposed FLC is constructed with three input variables which are the PV current, hydrogen storage level, and the battery state of charge. The rules-based fuzzy inference process is based on the proposed configuration which combines the advantages of direct and DC-DC converter coupling configurations. The simulation results show that the proposed configuration offers better adapta- bility to variable radiation conditions compared to other methods. This gives a more promising option for ensuring the adequacy of hydrogen supply at hydrogen refuelling stations.  相似文献   
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This work analyzes the limit cycle phenomena of nonlinear sampled-data systems by applying the methods of gain-phase margin testing, the M-locus and the parameter plane. First, a sampled-data control system with nonlinear elements is linearized by the classical method of describing functions. The stability of the equivalent linearized system is then analyzed using the stability equations and the parameter plane method, with adjustable parameters. After the gain-phase margin tester has been added to the forward open-loop system, exactly how the gain-phase margin and the characteristics of the limit cycle are related can be elicited by determining the intersections of the M-locus and the constant gain and phase boundaries. A concise method is presented to solve this problem. The minimum gain-phase margin of the nonlinear sampled-data system at which a limit cycle can occur is investigated. This work indicates that the procedure can be easily extended to analyze the limit cycles of a sampled-data system from a continuous-data system cases considered in the literature. Finally, a sampled-data system with multiple nonlinearities is illustrated to verify the validity of the procedure.  相似文献   
116.
Researchers have suggested that transformational leadership is an important aspect of effective schools; however, whether the effects vary across related studies and the robustness of the overall effect size remain unclear. A meta-analysis technique was used to synthesize the results of 28 independent studies and to investigate the overall relationship between transformational school leadership and three measures of school outcomes. The study found that, in terms of the mean effect sizes, transformational school leadership does have positive effects on teacher job satisfaction, school effectiveness perceived by teachers, and student achievement. Support for this paper was funded in part by the Taiwan’s National Science Council. The author is especially grateful to the two reviewers for their valuable comments and Dr. Jin-Fu Wu for his helps of statistical analysis.  相似文献   
117.
The understanding and development of cycling aerodynamics   总被引:1,自引:1,他引:0  
In elite cycling the resistive force is dominated by aerodynamics. Be it on the roads or in the velodrome, the sport has many examples where aerodynamics has won and lost races. Since the invention of the bicycle, engineers have strived to improve performance, often by reducing aerodynamic drag. Over the last 50 years a number of authors have presented their efforts in journals, books and magazines. This review summarises the publications that show the continued development in the aerodynamics of cycling. The review concludes by examining the shortcomings of the current understanding and making suggestions for future research and development.  相似文献   
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This paper proposes a remote vital signs monitoring system, which integrates wireless body area network (WBAN) and personal digital assistant (PDA) phone technology. Four different physiological signs, e.g., ECG, SpO2, temperature and blood pressure, can be continuously acquired or derived from two wireless sensor nodes—ECG sensor and integrated SpO2/temperature sensor. Once sentinel events happened or the request to real-time display vital signs is confirmed, all physiological signs and critical indices will be immediately transmitted to patient's PDA phone through Bluetooth and further relayed to doctor's PDA phone through global system for mobile communication (GSM) technology. A prototype of such system has been successfully developed and implemented, which will offer high standard of healthcare with a major reduction in cost for our society.  相似文献   
120.
1997年中国成年人体质监测公报   总被引:46,自引:3,他引:43  
监测未用随机整群取样方法,监测对象是 19个省、区、市的年龄为 18~60岁(女 55岁)的公民,最终参加运算的样本为 105 328人,获得 3 007 142个有效数据。主要结果为:男子平均身高为169.2 cm,女子为 158.6 cm;男子平均体重为 66.5 kg,女子为 56.8 kg。50岁前体重、相对体重随年龄增大,50岁后略减;北方人身材高大,南方人身材瘦小;东部地区人群体质好于中、西部。中国成年人体质方面存在的问题主要是有28.6%的人未达测定合格标准、开始向肥胖型发展等。提出改善中国成年人体质状况的主要措施主要有加强宣传,提高认识,扩大监测,吸引成年人参加体育活动等。  相似文献   
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