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从《物理化学(上册)》的首个教学章节“热力学第一定律”出发,以“雨课堂”和“腾讯课堂”为教学平台,分析了学生应该如何适应从“线下教学”到“线上教学”的转变,扮演好“学生”在网络教学中的角色,并以学生的这些注意事项为切入点,论述了教师应该做出的相应转变,以求引导学生更高效地完成线上学习任务。 相似文献
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以“探究水的组成”教学为例,通过课标、教材及学习者分析,从认识角度、探究水平、认识水平等3个维度整体规划“身边的化学物质”主题单元目标学习进阶,明确“探究水的组成”课时目标,通过温故建模、据模探究、探究推理等3个阶段的教学实施,建立具体物质的研究思路模型,运用模型研究陌生物质(氢气),初步形成定量研究物质组成的能力。 相似文献
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以“基于桃酥烘培配方的实验探究”单元课的设计与实施为例,从情境素材的选取、课堂问题的设计、课堂任务的确定、学习活动的设计、持续性评价方案的设计等方面论述了促进“深度学习”教学的生成过程。 相似文献
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介绍一个结合4种教学策略(情境教学、探究性学习、合作学习、混合式教学)面向非化学专业类大一学生开展元素化学教学的案例。以垃圾分类为主题,学生分组协作完成探究性学习任务,调查不同种类垃圾中存在的化学元素及其用途,通过线下课堂展示、线上成果共享以及校外推广等3项活动传播探究结论。对比活动前后收集的数据,活动前有75%的学生只认识原子序数前20的化学元素,活动后学生认识的元素数量明显增多,平均值是原来的1.7倍。元素中文名称与元素符号记忆混乱的情况得到改善。最后问卷调查表明活动提高了学生上课的积极性并且对了解生活中的化学元素有帮助。 相似文献
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RNA secondary structure prediction is a key technology in RNA bioinformatics. Most algorithms for RNA secondary structure prediction use probabilistic models, in which the model parameters are trained with reliable RNA secondary structures. Because of the difficulty of determining RNA secondary structures by experimental procedures, such as NMR or X-ray crystal structural analyses, there are still many RNA sequences that could be useful for training whose secondary structures have not been experimentally determined. In this paper, we introduce a novel semi-supervised learning approach for training parameters in a probabilistic model of RNA secondary structures in which we employ not only RNA sequences with annotated secondary structures but also ones with unknown secondary structures. Our model is based on a hybrid of generative (stochastic context-free grammars) and discriminative models (conditional random fields) that has been successfully applied to natural language processing. Computational experiments indicate that the accuracy of secondary structure prediction is improved by incorporating RNA sequences with unknown secondary structures into training. To our knowledge, this is the first study of a semi-supervised learning approach for RNA secondary structure prediction. This technique will be useful when the number of reliable structures is limited. 相似文献
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Organic light-emitting diode (OLED) materials have exhibited a wide range of applications. However, the further development and commercialization of OLEDs requires higher quality OLED materials, including materials with a high thermal stability. Thermal stability is associated with the glass transition temperature (Tg) and decomposition temperature (Td), but experimental determinations of these two important properties generally involve a time-consuming and laborious process. Thus, the development of a quick and accurate prediction tool is highly desirable. Motivated by the challenge, we explored machine learning (ML) by constructing a new dataset with more than 1,000 samples collected from a wide range of literature, through which ensemble learning models were explored. Models trained with the LightGBM algorithm exhibited the best prediction performance, where the values of mean absolute error, root mean squared error, and R2 were 17.15 K, 24.63 K, and 0.77 for Tg prediction and 24.91 K, 33.88 K, and 0.78 for Td prediction. The prediction performance and the generalization of the ML models were further tested by two applications, which also exhibited satisfactory results. Experimental validation further demonstrated the reliability and the practical potential of the ML-based models. In order to extend the practical application of the ML-based models, an online prediction platform was constructed. This platform includes the optimal prediction models and all the thermal stability data under study, and it is freely available at http://www.oledtppxmpugroup.com. We expect that this platform will become a useful tool for experimental investigation of Tg and Td, accelerating the design of OLED materials with desired properties. 相似文献
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化学系统性思维强调化学子系统之间,以及化学系统与其他学科系统之间的关系,有助于学习者整合、应用化学知识解释化学现象、解决化学问题。内外交织的多个不同系统很容易让学生迷失在纷繁复杂的概念体系中,需要借助SOCME,OPM,BOTG,CLD,SFD等可视化图形工具厘清各个系统之间的关系,以表征化学系统性思维。在明确化学系统性思维内涵的基础上,开展“化学平衡”教学改革,探索绿色化学课程建设,开展游戏化学习、服务性学习、深度学习、项目学习、工作坊或研讨会,有助于化学系统性思维培养实践的改革与落地。横向关联化学系统与其他学科系统的关系,纵向深入分析化学子系统之间的关系,是进一步开展化学系统性思维教学的关键。这就需要多学科的协同攻关,既要关注化学知识的社会应用,也要抓住化学学科本质和特征,才可以围绕化学概念和社会问题,建构纵横交织的多系统影响关系,促进学生化学系统性思维的发展。 相似文献
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设计了《影响高中生化学有效学习因素调查问卷》,在具有代表性的普通中学进行大样本的问卷调查,调查数据经计算机统计处理,结果发现:学习习惯、学习方法、学习内容难度等3个维度对高中生有效学习具有显著影响,学习环境维度对高中生有效学习影响不明显;这4个维度对男女生的影响差别不是很大,但对不同年级学生的影响度发生了变化。由此可以为中学一线化学教师的有效教学策略提供有益的启示。 相似文献
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Multi-instance multi-label (MIML) learning has been proven to be effective for the genome-wide protein function prediction problems where each training example is associated with not only multiple instances but also multiple class labels. To find an appropriate MIML learning method for genome-wide protein function prediction, many studies in the literature attempted to optimize objective functions in which dissimilarity between instances is measured using the Euclidean distance. But in many real applications, Euclidean distance may be unable to capture the intrinsic similarity/dissimilarity in feature space and label space. Unlike other previous approaches, in this paper, we propose to learn a multi-instance multi-label distance metric learning framework (MIMLDML) for genome-wide protein function prediction. Specifically, we learn a Mahalanobis distance to preserve and utilize the intrinsic geometric information of both feature space and label space for MIML learning. In addition, we try to deal with the sparsely labeled data by giving weight to the labeled data. Extensive experiments on seven real-world organisms covering the biological three-domain system (i.e., archaea, bacteria, and eukaryote; Woese et al., 1990) show that the MIMLDML algorithm is superior to most state-of-the-art MIML learning algorithms. 相似文献