2,748 research outputs found

    Quasi-period outflows observed by the X-Ray Telescope onboard Hinode in the boundary of an active region

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    Persistent outflows have recently been detected at boundaries of some active regions. Although these outflows are suggested to be possible sources of the slow solar wind, the nature of these outflows is poorly understood. Through an analysis of an image sequence obtained by the X-Ray Telescope onboard the Hinode spacecraft, we found that quasi-period outflows are present in the boundary of an active region. The flows are observed to occur intermittently, often with a period of 5-10 minutes. The projected flow speed can reach more than 200 km/s, while its distribution peaks around 50 km/s. This sporadic high-speed outflow may play an important role in the mass loading process of the slow solar wind. Our results may imply that the outflow of the slow solar wind in the boundary of the active region is intermittent and quasi-periodic in nature.Comment: 5 figures, accepted by RA

    An Evaluation Model for Tailings Storage Facilities Using Improved Neural Networks and Fuzzy Mathematics

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    With the development of mine industry, tailings storage facility (TSF), as the important facility of mining, has attracted increasing attention for its safety problems. However, the problems of low accuracy and slow operation rate often occur in current TSF safety evaluation models. This paper establishes a reasonable TSF safety evaluation index system and puts forward a new TSF safety evaluation model by combining the theories for the analytic hierarchy process (AHP) and improved back-propagation (BP) neural network algorithm. The varying proportions of cross validation were calculated, demonstrating that this method has better evaluation performance with higher learning efficiency and faster convergence speed and avoids the oscillation in the training process in traditional BP neural network method and other primary neural network methods. The entire analysis shows the combination of the two methods increases the accuracy and reliability of the safety evaluation, and it can be well applied in the TSF safety evaluation

    Balancing supportive relationships and developing independence:An activity theory approach to understanding feedback in context for Master’s students

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    Master’s students are expected to be self-regulating and independent learners. Dialogic feedback has been identified as one way of promoting such independence. There continues to be concern about the extent to which master’s students are achieving this level of functioning. This study aimed to identify feedback practices and contexts which facilitated student engagement and independence. Working with students as co-researchers, interviews were conducted with 27 master’s students from three programmes. Activity theory was used as an analytical tool to generate understanding of feedback in the social context of each programme. Findings indicate there can be tension between factors which promote dialogical feedback and those which promote independence, and that active dialogic feedback with staff may limit student engagement with peer feedback
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