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1.
A computer prediction for the regularities of formation of binary bromide system was made. The results indicate that
CsBr-CaBr2 molten salt system is binary complex compound-forming system. The phase diagram of CsBr-CaBr2 system has been
determined by visual polythermal method in order to prove the prediction. The phase diagrams of the quasibinary system KCl-CsBr,
KC1-CaBr2 and the quasiternary system CsBr-CaBr2-KC1 were determined by using visual polythermal method. The phase diagrams of
CsBr-CaBr2 and KCl-CaBr2 show that the intermediate compound is formed. The results are in agreement with the computer prediction.
Here, the various parts of the phase diagram of the quasiternary system CsBr-CaBr2-KCl were discussed. 相似文献
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1 Introduction Molten salts are considered to be used as fluid tar-gets in the nuclear incineration of transuranic elementswith proto accelerators .The molten salts are also usedas the media in high temperature chemical reprocess-ing of spent nuclear fuel of fast reactors .The phase di-agrams of rare earth metal halides in combination withalkali metal halide systems are of pri me i mportance inapplication. The thermodynamic properties and phase diagramsof the DyCl3-MClnsystems ( M =alkali or… 相似文献
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1 Introduction Molten salts are considered to be used as fluid tar-gets in the nuclear incineration of transuranic elementswith proto accelerators .The molten salts are also usedas the media in high temperature chemical reprocess-ing of spent nuclear fuel of fast reactors .The phase di-agrams of rare earth metal halides in combination withalkali metal halide systems are of pri me i mportance inapplication. The thermodynamic properties and phase diagramsof the DyCl3-MClnsystems ( M =alkali or… 相似文献
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提出由计算机辅助设计（ＣＡＤ）、计算机视觉和计算机辅助检测规划（ＣＡＩＰ）与三坐标测量机（ＣＭＭ）集成构成的柔性自动坐标测量系统中使用的计算机视觉识别和定位定向的方法．给出了识别方法——多重定向执行长度编码（ＭＯＲＬＣ）的原理和工作过程及基于被测工件影像转动惯量的定位定向方法．结果表明,将计算机视觉技术集成到测量系统中是提高测量系统的柔性和自动化程度的一条行之有效的途径 相似文献
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Mr Richard K. Lowe 《Research in Science Education》1990,20(1):191-199
Two contrasting methods of investigation were used to characterise the basis upon which the mental representation of a scientific
diagram was organised in individuals having different levels of experience and skill in the interpretation of this type of
diagram. Each of these methods is described and several important methodological issues are discussed. In the first method
(the Card Sort method), subjects performed a three-stage grouping of diagram elements in a card sorting task that produced
an hierarchical ordering of the information constituting the diagram. In the second method (the Copy-Recall method), subjects
copied then produced drawn recall of a given diagram. Measurements of the sequence in which diagram elements were produced
and the time intervals between each production were used to infer the underlying cognitive structuring involved in the mental
representation of the diagram information. Questions are raised concerning the way resulting data can be analysed and interpreted
most effectively.
Specializations: Mental representation and processing of scientific diagrams, characteristics of explanatory diagrams, visual aspects of problem
solving, instructional design. 相似文献
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Matthew T. McCrudden Gregory Schraw Stephen Lehman Anne Poliquin 《Contemporary educational psychology》2007
We examined the effect of studying a causal diagram on comprehension of causal relationships from an expository science text. A causal diagram is a type of visual display that explicitly represents cause-effect relationships. In Experiment 1, readers between conditions did not differ with respect to memory for main ideas, but the readers who studied the causal diagram while reading the text understood better the five causal sequences in the text even when study time was controlled. Participants in Experiment 2 studied only the causal diagram or only the text. There were no differences in memory for main ideas or the causal sequences between these groups. Results indicate that causal diagrams are not merely redundant with text and that causal diagrams affect understanding of causal relationships in the absence of a text. These findings supported the causal explication hypothesis, which states that causal diagrams improve comprehension by explicitly representing the implicit causal structure of the text in a visual format. 相似文献
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Computercalculationofphasediagramsbeganmorethan30yearsago.Aclearanddetailedreviewoftheearlyworksl'-'lwascontributedbyAnewton-Raphsoniterationtechniqueandthesimplexmethod,andpointedoutthatthemathematicaldeductionsofthelatterarelesscomplicated.Manynsaral'I.… 相似文献
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通过Adams—Bashforth—Moulton方法和predictor corrector algodn瑚方法并结合分数阶稳定性理论,辅助以相图、脉冲响应曲线、分叉图等分析了Jerk系统的动力学行为;引入反馈控制法对系统进行控制,最终得到理想的结果,并将其应用于保密通讯。Matlab值仿真验证了其有效性。 相似文献
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Previous experiments have shown a deleterious effect of visual representations on college students’ ability to solve total- and joint-probability word problems. The present experiments used conditional-probability problems, known to be more difficult than total- and joint-probability problems. The diagram group was instructed in how to use tree diagrams to solve conditional probability problems; the equation-only group was instructed only in the formulation of equations. Results indicated that the diagram group outperformed the equation-only group on a posttest of 10 near- and far-transfer problems given immediately and as long as 1 week later (Experiment 2). In addition, when rating their experience with the training phase the equation-only group reported significantly higher levels of frustration and lower levels of perceived success than the diagram group. 相似文献
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Two experiments investigated how signals foster learning from text and diagrams by examining the relationship between visual attention and learning outcomes. In Experiment 1 (N = 55) students learned about the circulatory heart system from a multimedia lesson either with or without signals highlighting text–diagram correspondences. Results showed that students learning with signals attended to signaled (but not to non-signaled) information more frequently and earlier during learning; these changes in visual attention could explain better performance in answering text–diagram-integration questions. Experiment 2 (N = 78) replicated these findings with respect to early attention on signaled diagram elements and learning outcomes; in addition, a third condition was investigated, where signals highlighted diagram elements that did not match the text. Results showed that mismatched signals guided attention only initially, whereas later on students attended more to information that corresponded to the text. Mismatched signals had no effect on learning outcomes. Taken together, the results suggest that signals aid learning by highlighting specific text–diagram correspondences and not by amplifying diagram processing more generally. 相似文献
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Marco Kragten Wilfried Admiraal Gert Rijlaarsdam 《Research in Science Education》2013,43(5):1785-1800
Students in secondary science education seem to have difficulties with understanding diagrams. The present study focused on explanatory factors that predict students’ difficulties with process diagrams, i.e., diagrams that describe a process consisting of components that are related by arrows. From 18 compulsory national Biology exams of secondary school pre-university students, all process diagram tasks (n?=?64) were included in corpus. Features of the task, student, and diagram were related to the difficulty of that particular task, indicated by the cohort mean exam score. A hierarchical regression analysis showed main effects for (1) the cognitive task demand, (2) the familiarity of the components, and (3) the number of components in a diagram. All these main effects were in the expected direction. We also observed interactions. Within the category of tasks with a high cognitive demand, tasks about a diagram of which students have low prior content knowledge were more difficult than tasks about a diagram of which students have high prior content knowledge. Tasks with a high cognitive demand about a diagram with familiar arrows were, surprisingly, more difficult than tasks with a high cognitive demand about a diagram with unfamiliar arrows. This latter finding might be attributed to compensation for task difficulty by the large number of components in the diagrams involved. The final model explained 46 % of the variance in exam scores. These results suggest that students have difficulties (1) with tasks that require a deeper understanding when the content is new, (2) with diagrams that use unfamiliar component conventions, and (3) with diagrams that have a small number of components and are therefore probably more abstract. 相似文献
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William Winn Cliff Solomon 《Educational technology research and development : ETR & D》1993,41(1):29-41
In two experiments, subjects received problem sets consisting of a simple diagram accompanied by two sentences and were asked to select the sentence that best expressed the meaning of the diagram. Each diagram showed a relationship between two concepts. The relationships were category membership, possession of a property, and causality. The relative placement of the concepts was varied. In the first experiment, the concepts were given nonsense names. Significant biases in response frequencies were found, suggesting that, in the absence of semantic content, the interpretation of the diagrams was largely determined by syntactic rules of English. In the second experiment, similar biases were found for diagrams whose concepts were given English names. However, the biases were less evident when the diagrams violated the rules of English syntax. This suggested that conflict between the sense of English and a diagram's spatial arrangement makes consistent interpretation unlikely. Conclusions are drawn concerning the relationships between the spatial arrangement of diagrams and the meaning of relationships among concepts stated in sentences. Suggestions for diagram design are offered. 相似文献
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王立明 《廊坊师范学院学报(自然科学版)》2009,9(4):56-59
对“旋转单摆”的运动进行研究,建立系统的动力学方程,用线性稳定性分析方法讨论平衡点附近邻域的稳定性,给出了系统静态分岔图和运动的相图,利用Jacobi椭圆函数得出不同转速下系统作周期运动的解析解,并绘出图形加以说明。 相似文献
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为了节约软件测试成本,减少测试用例数量,提出了一种利用蚁群算法直接从UML活动图中生成测试用例的方法。通过对UML活动图和蚁群算法进行形式化规约,构造人工蚁群,然后依据DFS遍历由UML活动图转化的有向连通图G,最后生成测试用例。通过仿真模拟,对提出的方法进行验证以及对实验结果进行分析,证明了该算法的可行性和有效性。 相似文献
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Jennifer G. Cromley Tony C. Perez Shannon L. Fitzhugh Nora S. Newcombe Theodore W. Wills Jacqueline C. Tanaka 《Journal of Experimental Education》2013,81(4):511-537
The authors tested whether students can be taught to better understand conventional representations in diagrams, photographs, and other visual representations in science textbooks. The authors developed a teacher-delivered, workbook-and-discussion–based classroom instructional method called Conventions of Diagrams (COD). The authors trained 1 experienced teacher to deliver COD to two 10th-grade biology classes (n = 31) and compared gains in diagram comprehension from COD to those from a business-as-usual control condition (n = 30) in 2 classrooms taught by the same teacher. Students in the COD condition showed statistically significantly greater growth in comprehension of literal and inferential biology diagrams. The control condition in some cases advantaged high-spatial, high-knowledge students, whereas the COD condition for the most part did not. Entries in the COD workbooks were analyzed for amount of student effort. Students with a combination of low pretest biology knowledge and low effort showed much lower gains from pretest to posttest on the inferential biology diagrams measure than did other students in the COD condition. 相似文献