职前化学教师对“科学探究”理解水平的调查研究*

采用美国诺尔曼·莱德曼(Norman G. Lederman)和朱迪斯·莱德曼(Judith S. Lederman)编制的科学探究观(View About Scientific Inquiry, VASI)调查问卷,对38位职前化学教师的科学探究观进行了调查。结果发现,职前化学教师对科学探究的理解水平参差不齐,理解水平最好的是维度三(D3),74%的职前化学教师对该维度持“通晓的(Informed)”观点;理解水平中等的是维度二(D2),66%的职前化学教师对该维度持“混合的(Mixed)”观点;理解水平最差的是维度七(D7),61%的职前化学教师对该维度持“朴素的(Naive)”观点,并且没有人对该维度持“通晓的”观点,针对这种情况,提出3条改进策略:一是“显性化”,在课程标准和教科书中以“显性”的方式呈现有关科学探究理解的内容;二是“活动化”,教师在教学中设计并实施基于理解探究的各种实践活动;三是“反思性”,引导学生积极主动地反思科学探究活动,获取对科学探究的深入理解。     

Do students really understand what an ordinary differential equation is?

Differential equations (DEs) are important in mathematics as well as in science and the social sciences. Thus, the study of DEs has been included in various courses in different departments in higher education. The importance of DEs has attracted the attention of many researchers who have generally focussed on the content and instruction of DEs. However, DEs are complex issues that students may find difficulty to understand. The limited research in this literature points to the need for more studies on students’ conceptions, and understanding of DEs and their basic concepts. The objective of this study is to fill this need by revealing the understanding, difficulties and weaknesses of the students who are successful in algebraic solutions, in relation to the concepts of DEs and their solutions. For this purpose, 77 students were asked 13 DE questions (6 of them about algebraic solution, and the rest about interpreting DEs and their solutions). From an analysis of the students’ answers, it was concluded that the students who were quite successful in algebraic solutions, indeed did not fully understand the related concepts, and they had serious difficulties in relation to these concepts.     

Crystallographic Understanding of Photoelectric Properties for C60 Derivatives Applicable as Electron Transporting Materials in Perovskite Solar Cells

Hundreds of C₆₀ derivatives stand out as electrontransporting materials(ETMs), for example, in perovskite solar cells(PSCs), due to their properties on electron extraction or defect passivation. However, it still lacks of guidelines to update C₆₀-based ETMs with excellent photoelectric properties. In this work, crystallographic data of eight C₆₀-based ETMs, including pristine C₆₀ and the well-known PCBM as well as six newly synthesized fullerenes, are analyzed to establish the connections between derivatized structures and photoelectric properties for the typical carbon cluster of C₆₀. In terms of packing centroid-centroid distance between neighboring carbon cages, the crystallographic data are useful for probing photoelectric properties, such as electrochemical properties, electron mobility and photovoltaic performances, and therefore facilitate to design novel C₆₀-based ETMs for PSCs with high performances.     

Self-generated dynamic landscape: The message–receiver interaction case

In the present work we present a model, based on a particular differential stochastic equation, to study the interaction between an incoming message and its interpreter. The particular stochastic dynamic used to understand such process is written using a delayed Langevin equation with white noise. The results of this kind of interaction can be understood in a general framework that we name the self generated dynamic landscape.     

语言声学与内容理解研究进展

本文对语言声学与内容理解研究的最新进展进行综述。首先介绍人类的言语的产生、感知以及声学分析方面的进展,接着分别介绍采用计算机来对语音中的各种信息进行抽取(包括语音、说话人和语种识别)和内容分析与理解(包括文档内容分析和理解与对话)的最新成果,最后对语言声学与内容理解的研究进行了总结和展望。     

对工科高等数学的研究性教学的一些认识

当前"研究性教学"是比较提倡的教学方式,它有利于培养学生的数学思想和数学素养.为了更好地进行"研究性教学",教师应研究数学史培养学生数学思想,应研究数学教学的认知规律培养学生"研究性学习"习惯,以及进行应用数学知识能力的研究,完美的逻辑体系与学生接受能力的研究,支持这种教学方式的考核方式的研究.     

Spatial classification

The aim of a spatial classification is to position the units on a spatial network and to give simultaneously a set of structured classes of these units “compatible” with the network. We introduce the basic needed definitions: compatibility between a classification structure and a tessellation, (m,k)-networks as a case of tessellation, convex, maximal and connected subsets in such networks, spatial pyramids and spatial hierarchies. As like Robinsonian dissimilarities induced by indexed pyramids generalize ultrametrics induced by indexed hierarchies we show that a new kind of dissimilarity called “Yadidean” induced by spatial pyramids generalize Robinsonian dissimilarities. We focus on spatial pyramids where each class is a convex for a grid, and we show that there are several one-to-one correspondences with different kinds of Yadidean dissimilarities. These new results produce also, as a special case, several one-to-one correspondences between spatial hierarchies (resp. standard indexed pyramids) and Yadidean ultrametrics (resp. Robinsonian) dissimilarities. Qualities of spatial pyramids and their supremum under a given dissimilarity are considered. We give a constructive algorithm for convex spatial pyramids illustrated by an example. We show finally by a simple example that spatial pyramids on symbolic data can produce a geometrical representation of conceptual lattices of “symbolic objects”.     

Local hardness: a critical account

This paper gives a critical account on the present status of the local hardness. We analyze the behavior of hardness related global, local, and nonlocal properties, paying particular attention to local hardness. Although this reactivity index has become very useful in predicting the regioselectivity of chemical reactions, the lack of a rigorous definition in the literature has shown that different approximations can yield different and sometimes contradictory conclusions. The present paper tries to provide insights into this controversial issue, starting from an approximate model of the hardness kernel and analyzing the features of the different models to evaluate the local and global hardnesses.     

创新产品目标设计阶段的需求分析和研究

本针对创新产品目标设计阶段的顾客需求进行研究，分析了需求的层次、需求的类型以及需求的特点，探讨了识别需求的方法、途径和所需注意的问题，论述了需求分析的方法、手段和重要性。最后，给出了需求的产品设计规范所包含的内容及一般的表达形式。     

数字散斑条纹处理的频域法和空域法

通过对数字散斑干涉条纹散斑噪声分布规律的分析，本文提出一种用于ＤＳＰＩ条纹降噪声处理的空域滤波法－复合区域平均法。处理结果表明，该方法仅处理速度快而且其去噪声效果能与ＤＣＴ方法相媲美。