理科职前教师科学模型理解的调查研究

就科学模型的理解对553名理科职前教师进行问卷调查。结果发现：（1）职前教师对科学模型的认识处于中上水平,仍需进一步提高;（2）科学模型的多个维度之间职前教师的理解水平相当;（3）职前教师对科学模型的认识并非随年级逐渐递增,具有不稳定性、反复性;（4）专业学习内容的差异对教师科学模型的认识有着重要影响;（5）科学模型的认识性别差异不明显。基于此提出了关于理科职前教师教育中加强科学模型教学的3点启示。     

Interpretation of environmental tracer data for conceptual understanding of groundwater flow: an application for fractured aquifer systems in the Kłodzko Basin,Sudetes, Poland

Environmental isotopes and hydrogeological data have been used for the construction of a conceptual model of fresh groundwater flow in the K?odzko Basin, Sudetes, Poland. The model has allowed the verification of a groundwater circulation scheme resulting from the general morphological assumptions and the recharge role to the surrounding mountains. Combined interpretation of the tritium ages and the isotopic altitude effect allowed determining the volume of water-bearing rock V_r and hydrogeological parameters of systems drained by springs and wells. Prior to the final determination of the recharge zone of individual objects, calculations were made for the thickness of the flow zone (h) and the distance from the recharge zone to the drainage point (L). The recharge areas for springs are located within a distance of 1–1.5 km and are characterized by a width of 0.75–1.65 km. The recharge area of wells is located in significantly longer distances of 2.1–12 km but yet definitely lower width. The recharge of groundwater from the Western direction seems to be obvious for all the wells and springs located westward from Nysa K?odzka River. The eastern component of the recharge appeared during the interpretation of the well in D?ugopole.

Dedicated to Professor Peter Fritz on the occasion of his 80th birthday     

试论“中学生理解科学探究”评价指标体系的构建

在综合国内外科学教育专家、学者对“理解科学探究”所持观点的基础上,提出了“理解科学探究”评价框架。以此为基础,结合中学生的特点,构建出中学生“理解科学探究”的评价指标体系。     

Examining prospective mathematics teachers' pedagogical content knowledge on fractions in terms of students' mistakes

The aim of the study is to examine prospective mathematics teachers’ pedagogical content knowledge in terms of knowledge of understanding students and knowledge of instructional strategies which are the subcomponents of pedagogical content knowledge. The participants of this research consist of 98 prospective teachers who are studying in two universities in Turkey. The participants were selected with the purposive sampling method which is one of the non-random sampling methods. Case study method, which is based on the qualitative research approach, was used. The answers given by secondary school students to fraction-related open-ended questions in the study of Soylu and Soylu were used as the data collection tool. The obtained data were analyzed via the content analysis technique. The analyses showed that the prospective mathematics teachers’ pedagogical content knowledge on fractions was not at an adequate level in identifying and correcting students’ errors. However, it was observed that the prospective teachers experienced more difficulty in the knowledge of instructional strategies compared to the knowledge of understanding students.     

Mathematics education graduate students’ understanding of trigonometric ratios

This study describes mathematics education graduate students’ understanding of relationships between sine and cosine of two base angles in a right triangle. To explore students’ understanding of these relationships, an elaboration of Skemp's views of instrumental and relational understanding using Tall and Vinner's concept image and concept definition was developed. Nine students volunteered to complete three paper and pencil tasks designed to elicit evidence of understanding and three students among these nine students volunteered for semi-structured interviews. As a result of fine-grained analysis of the students’ responses to the tasks, the evidence of concept image and concept definition as well as instrumental and relational understanding of trigonometric ratios was found. The unit circle and a right triangle were identified as students’ concept images, and the mnemonic was determined as their concept definition for trigonometry, specifically for trigonometric ratios. It is also suggested that students had instrumental understanding of trigonometric ratios while they were less flexible to act on trigonometric ratio tasks and had limited relational understanding. Additionally, the results indicate that graduate students’ understanding of the concept of angle mediated their understanding of trigonometry, specifically trigonometric ratios.     

结构化学和计算化学有机结合实现“1+1>2”追求理解的学习

针对结构化学和计算化学的课程特点和学生学习两门课时的学情分析,提出了结构化学和计算化学在授课过程中有机结合、相互渗透,实现“1+1>2”的教学效果和追求理解的学习,为学生理解结构化学的抽象概念和理论以及理解计算化学的基础知识提供一种很好的学习方法,也为教师提供一种很好的教学策略。     

Multiply Charged Anions,Maximum Charge Acceptance,and Higher Electron Affinities of Molecules,Superatoms,and ClustersSCI北大核心CSCD

The addition of electrons to form gas-phase multiply charged anions (MCAs) normally requires sophisticated experiments or calculations.In this work, the factors stabilizing the MCAs, the maximum electron uptake of gas-phase molecules, X, and the electronic stability of MCAs X^Q-, are discussed. The drawbacks encountered when applying computational and/or conceptual density functional theory (DFT) to MCAs are highlighted. We develop and test a different model based on the valence-state concept. As in DFT, the electronic energy, E(N, v_ex), is a continuous function of the average electron number, N, and the external potential, v_ex, of the nuclei. The valence-state-parabola is a second-order polynomial that allows extending E(N, v_ex) to dianions and higher MCAs. The model expresses the maximum electron acceptance, Q_max, and the higher electron affinities, A_Q, as simple functions of the first electron affinity, A₁, and the ionization energy, I, of the "ancestor" system. Thus, the maximum electron acceptance is Q_{max, calc} = 1 + 12A₁/7(I -A₁). The ground-state parabola model of the conceptual DFT yields approximately half of this value, and it is termed Q_{max, GS} = ${}^{1}\!\!\diagup\!\!{}_{2}\; $ + A₁/(I -A₁). A large variety of molecules are evaluated including fullerenes, metal clusters, super-pnictogens, super-halogens (OF₃), super-alkali species (OLi₃), and neutral or charged transition-metal complexes, AB_mL_n^0/+/-. The calculated second electron affinity A_{2, calc} = A₁-(7/12)(I -A₁) is linearly correlated to the literature references A_{2, lit} with a correlation coefficient R = 0.998. A₂ or A₃ values are predicted for further 24 species. The appearance sizes, n_ap^3-, of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.     

Projections of three-dimensional regions

The aim of this note is to improve the teaching of triple integrals.     

An operational definition of learning

An operational definition offered in this paper posits learning as a multi-dimensional and multi-phase phenomenon occurring when individuals attempt to solve what they view as a problem. To model someone's learning accordingly to the definition, it suffices to characterize a particular sequence of that person's disequilibrium-equilibrium phases in terms of products of a particular mental act, the characteristics of the mental act inferred from the products, and intellectual and psychological needs that instigate or result from these phases. The definition is illustrated by analysis of change occurring in three thinking-aloud interviews with one middle-school teacher. The interviews were about the same task: “Make up a word problem whose solution may be found by computing 4/5 divided by 2/3.”     

The Process Analytical Technology initiative and multivariate process analysis, monitoring and control

Process analytical technology is an essential step forward in pharmaceutical industry. Real-time analyzers will provide timely data on quality properties. This information combined with process data (temperatures, flow rates, pressure readings) collected in real time can become a powerful tool for this industry, for process understanding, process and quality monitoring, abnormal situation detection and for improving product quality and process reliability. A very important tool for this achievement is the multivariate analysis. Dr. Theodora Kourti is Research Manager in the McMaster Advanced Control Consortium (MACC) and Adjunct Professor in the Chemical Engineering Department at McMaster University. She is the co-recipient of the 2003 University – Industry Synergy Award for Innovation, given by the Natural Science & Engineering Research Council of Canada. Dr. Kourti has been working on Multivariate Statistical Methods for Process and Product Improvement and Abnormal Situation Detection in Process Industries since 1992 and has been involved in more than 80 major industrial applications in North America and Europe. These are either off-line or real-time applications for batch and continuous processes, in diverse industries such as Chemicals, Pharmaceuticals, Semiconductor, Mining, Pulp and Paper, Petrochemicals, Photographic and Steel Industry. She has published extensively in this area and has provided training for numerous industrial practitioners.