农村学生数学语言表达能力的培养探讨

发展农村学生的数学语言表达能力,是提高学生交流能力的根本。教师要用规范的语言对学生施以良好的影响,持之以恒地对学生进行说话训练,注重培养学生良好的说话习惯。文章从农村学校教学现状、运用数学语言改善农村教学环境、培养学生数学语言表达能力的策略、数学语言表达能力培养效果等方面进行论述。     

Multiple Outcomes of Class Visits to Natural History Museums: The Students’ View

The purpose of this study was to describe and understand the range of outcomes of class visits to natural history museums. The theoretical framework is based on the multifaceted process of learning in free choice learning environments, and emphasizes the unique and individual learning experience in museum settings. The study’s significance is in highlighting several possible cognitive as well as non-cognitive learning effects in museums class visits, by providing the student’s point of view. Data was collected by semi-structured interviews with 50 students in grades 6–8 on the day following the visit. We present evidence that students expressed several learning outcomes, connected directly and indirectly to the scientific content of the visit. Content oriented outcomes included acquiring scientific knowledge and making connections to prior knowledge; social oriented outcomes were identified in students’ statements regarding communicating knowledge and social aspects of learning; and interest oriented outcomes were evidenced by students’ expressions about emotions, interest and curiosity. The aggregate data addressed the common outcomes and the impact of class visits to natural history museums in the short term. Comparisons between two types of museums show significant differences in several aspects, regarding the exhibit and/or the activity type. Practical ideas for structuring the ultimate experience are included.     

Metacognition and Self-Regulation in James,Piaget, and Vygotsky

This article investigates the intertwined constructs of metacognition and self-regulation as they emerge in the works and theories of James, Piaget, and Vygotsky. To coordinate this exploration, we use an interpretive framework based on the relation of subject and object. In this framework, James’s perspective on metacognition and self-regulation is aligned with the Self, Piaget’s with the other and object, and Vygotsky’s with the medium or agency of language. We explore how metacognition and self-regulation function within the realm of human behavior and development as described in the works of each of these theorists. Key questions or issues that emerge for current research are outlined, and the limitations and benefits of each theorist’s perspective vis-à-vis metacognition and self-regulation are discussed.     

Making Connections: Learning and Teaching Chemistry in Context

Even though several studies have reported positive attitudinal outcomes from context-based chemistry programs, methodological obstacles have prevented researchers from comparing satisfactorily the chemistry-learning outcomes between students who experience a context-based program with those who experience a content-driven program. In this narrative inquiry we are able to address the question: how do the recalled experiences of a student and her teacher in context-based and concept-based chemistry programs compare? From the student’s unique perspective of experiencing both programs with the same teacher, we have constructed our collective account around four themes; namely, the extent to which the student makes connections between chemistry concepts and real-world contexts, developing research independence through engaging in extended experimental investigations related to contexts, learning chemistry concepts through contexts, and conceptual sequencing in a context-based program. The student reported real-world connections between chemistry concepts and contexts, found her engagement in the context-driven tasks interesting and productive, and identified connected sequences of concepts across the contexts studied. Despite difficulties for teachers who are required to shift pedagogies, the student’s lived experiences and outcomes from a context-based program provide some encouragement in working through these issues.     

Establishing a Competence Profile for the Role of Student-centred Teachers in Higher Education in Belgium

The increasing importance of constructivism in higher education has brought about a shift in pedagogy from a focus on the teacher to a focus on the student. This has important implications for teaching and assessment. A student-centred pedagogy implies a different role for the teacher. What exactly does student-centred teaching require from teachers’ actual teaching practice? What is expected from them in order to teach in a student-centred way? It is in order to respond to these questions that this research project has been carried out establishing a core competence profile of student-centred teachers in higher education. Qualitative data were collected by means of semi-structured in-depth interviews with teachers from different institutions for higher education in Belgium, known for their student-centred way of teaching. This research method is innovative compared to the methods used for existing competence lists in the literature, which were usually developed on the basis of conversations with pedagogical experts. By exploring practice and having teachers participate in the development of a competence list, the acceptance of a competence profile is much higher. The result of the project is a validated competence profile which takes into account the critiques on existing competence lists. The competence profile provides a further insight in the functioning of teachers within a student-centred pedagogy and can be used as a starting point for the educational development of teachers within this pedagogy.     

Assessing the counselling needs of high school students in Kenya

The Student Counselling Needs Scale (SCNS) was administered to 867 participants recruited from high schools in Kenya. The data were analyzed using exploratory factor analysis yielding five factors: human relationships, career development, self development, social values, and learning skills were assessed. The findings highlighted the importance of using assessment instruments to identify students’ counselling needs in Kenya.     

固支Mindlin 板弯曲问题的辛本征解

Hamiltonian system for the problem on clamped Mindlin plate bending was established by introducing the dual variables for the generalized displacements in this letter. By separation of variables, the transverse eigen-problem was derived based on the sympletic geometry method. With the solved sympletic eigen-values, the generalized sympletic eigen-solution was derived through eigenfunction expansion. An example of plate with all edges clamped was given. The sympletic solution system was worked out directly from the Hamiltonian system. It breaks the limitation of traditional analytic methods which need to select basis functions in advance. The results indicate that the sympletic solution method could find its more extensive applications.     

Scaling behavior of nucleotide cluster in DNA sequences

In this paper we study the scaling behavior of nucleotide cluster in 11 chromosomes of Encephalitozoon cuniculi Genome. The statistical distribution of nucleotide clusters for 11 chromosomes is characterized by the scaling behavior of P（S） ∝ e^-αs＇ where S represents nucleotide cluster size. The cluster-size distribution P（S1＋S2） with the total size of sequential C-G cluster and A-T cluster S1＋S2 were also studied. P（S1＋S2） follows exponential decay. There does not exist the case of large C-G cluster following large A-T cluster or large A-T cluster following large C-G cluster. We also discuss the relatively random walk length function L（n） and the local compositional complexity of nucleotide sequences based on a new model. These investigations may provide some insight into nucleotide cluster of DNA sequence.     

Novel high torque bearingless two-sided rotary ultrasonic motor

Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM.     

周期数对光量子阱透射谱的影响

用传输矩阵法理论,研究周期数对一维光子晶体量子阱透射谱的影响,结果表明:随着阱层或垒层周期数的增大,光子晶体量子阱的透射峰均变窄,且垒层周期数增大时透射峰变窄的速度快;垒层介质高低折射率比值越大,或垒层周期数增大,光子晶体量子阱的透射峰变窄速度越快。这些特性,对提高光子晶体光学滤波器件的品质有指导意义。