“零起点”背景下一年级新生数数能力发展现状研究

当前，很多地方都在推行“零起点”教学，意在纠正学前教育和小学低年级教育中的“抢跑”现象。但儿童的学习起点现状究竟如何，很多教育工作者的判断往往停留在“感性的直觉”层面，这不利于“零起点”教学的推进和改善。为此，笔者围绕一年级新生数数能力的发展现状这一话题，以富森等人的儿童数数能力发展阶段理论为指导，开展了相关理性实证研究工作。

蜜蜂的数学能力

蜜蜂的大脑虽小,且神经元数量仅有人类大脑神经元的百万分之一,但它们却拥有非常高水平的群体智慧和个体智慧。与群体智慧相比,蜜蜂的个体智慧较不容易被人们所察觉。因此,主要探讨的方向是蜜蜂惊人的个体智慧——数学能力,并根据前人的研究结果,介绍蜜蜂的数数能力、对“零”的概念的理解以及简单的算数能力。

数数能力的培养及学具设计

设计说明:向中班幼儿提出10以内数数的要求似乎十分简单,其实要正确而迅速地数数并不容易。我们发现大多数四五岁幼儿仅停留在逐一点数的水平,一旦数得快或超过五的数量就易出错。我们认为,目测数群能力是幼儿数数能力的一个重要方面。为此,我们首先通过拍皮球、“开火车”等游戏让幼儿学会从10以内任何一个数接着往下数。在此基础上,我们有目的地设计、制作、投放大量供幼儿操作的学具(如下),引导幼儿积累“先目测一部分,再接着数完全部”的数数经验。这些学具有以下三个特点:①操作性强,能让幼儿动手动脑,反复练习。

数数

活动目标 1、引导幼儿学会手口一致地点数百以内正数、倒数。 2、培养幼儿数数能力。

Elastic and Thermodynamic Properties of CdSe from First-Principles Calculations

The lattice parameters, bulk modulus, phase transition pressure, and temperature dependencies of the elastic constants cij of CdSe are investigated by using the Cambridge Serial Total Energy Package （CASTEP） program in the frame of Density Functional Theory （DFT）. It is found that the phase transitions from the ZB structure to the RS structure and from WZ structure to RS structure are 2.2 GPa and 2.8 GPa, respectively. Our results agree well with the available experimental data and other theoretical results. The aggregate elastic modulus （B, G, E, A ）, the Poisson＇s ratio （v）, the Griuneisen parameter （γ）, the Debye temperature θD on pressure and temperature are also successfully obtained.

On the relation between home numeracy activities and preschool children＇s numeracy development

This mini-review focuses on the question of how home numeracy experience （i.e.,number-related activities at home） may affect a child＇s numeracy development. Evidence from young children suggests that trajectories of number learning differ for children having different home numeracy experiences. Children involved in higher frequency of direct numeracy practice tend to have higher numeracy skills, but the result becomes more complicated when considering the types of home numeracy activities. The relationship between the home numeracy experience and preschool children＇s nurneracy development may shed light on how children acquire number skills and develop their mathematics competence.

The Realistic Review on Elementary School Mathematics Teaching Reform

It is of benefit to the development of the elementary school quality-oriented mathematics education to deepen the elementary school mathematics classroom teaching reform and review the fruits of classroom teaching. In this paper, the author, with his own teaching practice, has summarized and reviewed the fruits of elementary school classroom teaching reform in four respects： 1） ＂integration of theory with practice＂ should be highlighted in this reform; 2） the classroom teaching should focus on the improvement of students＂ ＂mathematical thinking ability＂;3） mathematics classroom teaching should conform to the reality of our daily life; and 4） mathematics classroom teaching should help the students to build the ＂mathematical model thinking＂.

Pseudopotential Density-Functional Calculations for Structures of Small CarbonClusters CN （N=2-8）

We introduce a first-principles density-functional theory,i.e.the finite-difference pseudopotential density- functional theory in real space and the Langevin molecular dynamics annealing technique,to the descriptions of structures and some properties of small carbon clusters(C_N,N=2～8).It is shown that the odd-numbered clusters have linear structures and most of the even-numbered clusters prefer cyclic structures.

Research on the teaching reform of the university computer database

Along with the wide application and the rapid development of the database technology, the teaching of the database principle will focus on developing the students＇ innovative abilities and their application skills. On the basis of a comprehensive grasp of the concepts and principles, combined with the actual applications, the students will understand the development trend, and unceasingly enhance the level of the database knowledge, which has great benefits for training the comprehensive talents. In this paper, by analyzing the problems existing in the database courses, the author of this paper put forward the ideas and measures for the reform of the relevant curriculums.

Research on the teaching reform of the university computer database

Along with the wide application and the rapid development of the database technology, the teaching of the database principle will focus on developing the students＇ innovative abilities and their application skills. On the basis of a comprehensive grasp of the concepts and principles, combined with the actual applications, the students will understand the development trend, and unceasingly enhance the level of the database knowledge, which has great benefits for training the comprehensive talents. In this paper, by analyzing the problems existing in the database courses, the author of this paper put forward the ideas and measures for the reform of the relevant curriculums.

Open Approach-Based Subject Matter： A New Aspect of Mathematical Activity Fostering Students＇ Creativity

This study compares the subject matter appeared on traditional Thai textbooks and Japanese textbooks and analyzes how extension and integration sequence on Japanese textbooks evokes students＇ mathematical creativity. The data were collected from the series of four lessons in the fifth grade by teaching experiment methodology conducted following the professional development project implemented lesson study and open approach in Thailand. The results show that extension and integration sequence is an appropriate subject matter to generate lesson for problem-solving classroom. The sequence of lesson leads students to excitement, curiosity, confidence and intimacy in mathematics that are powerful effects of mathematical creativity. Students can produce the different and various ways to solve problems that indicate their divergent thinking.

Hybrid Improved Self-adaptive Differential Evolution and Nelder-Mead Simplex Method for Solving Constrained Real-Parameters

In this paper, a new hybrid algorithm based on exploration power of a new improvement self-adaptive strategy for controlling parameters in DE （differential evolution） algorithm and exploitation capability of Nelder-Mead simplex method is presented （HISADE-NMS）. The DE has been used in many practical cases and has demonstrated good convergence properties. It has only a few control parameters as number of particles （NP）, scaling factor （F） and crossover control （CR）, which are kept fixed throughout the entire evolutionary process. However, these control parameters are very sensitive to the setting of the control parameters based on their experiments. The value of control parameters depends on the characteristics of each objective function, therefore, we have to tune their value in each problem that mean it will take too long time to perform. In the new manner, we present a new version of the DE algorithm for obtaining self-adaptive control parameter settings. Some modifications are imposed on DE to improve its capability and efficiency while being hybridized with Nelder-Mead simplex method. To valid the robustness of new hybrid algorithm, we apply it to solve some examples of structural optimization constraints.

Research on the Applications of Advanced Mathematics on Mathematical Modeling and the Inner Connections with Linear Algebra and Probability Statistics

In this paper, we conduct research on the applications of advanced mathematics on the mathematical modeling and the inner connections with linear algebra and the probability statistics. Aiming at model in mathematical modeling and solving and model of evaluation and promotion of the two links, put forward the ＂bystander＂ and ＂the authorities＂ this two characters, and points out that excellent mathematical modeling participants should have ＂from a bystander to the authorities＂ and ＂from the authorities to return to bystanders＂ two-way role transformation ability. Great situation in mathematics teaching, by means of the mathematical modeling formed in the development of the teachers, as well as the teaching thought, teaching experience and achievements, the onward march of mathematical experiment should be faster than mathematical modeling. Our research provides the new paradigm for the math development which will be meaningful.

Robust low-rank data matrix approximations

We review some recent approaches to robust approximations of low-rank data matrices.We consider the problem of estimating a low-rank mean matrix when the data matrix is subject to measurement errors as well as gross outliers in some of its entries.The purpose of the paper is to make various algorithms accessible with an understanding of their abilities and limitations to perform robust low-rank matrix approximations in both low and high dimensional problems.

Numerical Investigation of Influence of Tip Leakage Flow on Secondary Flow in Transonic Centrifugal Compressor at Design Condition

In a centrifugal compressor, the leakage flow through the tip clearance generates the tip leakage vortex by the in- teraction with the main flow, and consequently makes the flow in the impeller passage more complex by the inte- raction with the passage vortex. In addition, the tip leakage vortex interacts with the shock wave on the suction surface near the blade tip in the transonic centrifugal compressor impeller. Therefore, the detailed examination for the influence of the tip leakage vortex becomes seriously important to improve the aerodynamic performance cs- pccia｜ly for the transonic centrifugal compressor. In this study, the flows in the transonic centrifugal compressor with and without the tip clearance at the design condition were analyzed numerically by using the commercial CFD code. The computed results revealed that the tip leakage vortex induced by the high loading at the blade tip around the leading edge affected the loss generation by the reduction or the suppression of the shock wave on the suction surface of the blade.

A novel stochastic collocation method for uncertainty propagation in complex mechanical systems

This paper presents a novel stochastic collocation method based on the equivalent weak form of multivariate function integral to quantify and manage uncertainties in complex mechanical systems. The proposed method, which combines the advantages of the response surface method and the traditional stochastic collocation method, only sets integral points at the guide lines of the response surface. The statistics, in an engineering problem with many uncertain parameters, are then transformed into a linear combination of simple functions' statistics. Furthermore, the issue of determining a simple method to solve the weight-factor sets is discussed in detail. The weight-factor sets of two commonly used probabilistic distribution types are given in table form. Studies on the computational accuracy and efforts show that a good balance in computer capacity is achieved at present. It should be noted that it's a non-gradient and non-intrusive algorithm with strong portability. For the sake of validating the procedure, three numerical examples concerning a mathematical function with analytical expression, structural design of a straight wing, and flutter analysis of a composite wing are used to show the effectiveness of the guided stochastic collocation method.

Numerical Study of Effects of Mach number on Aerodynamic Performance of Large Enthalpy Drop Stationary Cascade

Based on the method to change blade loading type along blade height, that is, applying aft-loading at both end zones of cascade while applying fore-loading in the mid zone of cascade, HTC(Harbin Turbine Company) designed a twisted and bowed stationary cascade with low aspect ratio and large enthalpy drop. To verify the aerodynamic performance of such cascade, firstly, low-speed wind tunnel tests were conducted to validate the calculation results of commercial software CFX, and then numerical simulations were made for the aerodynamic performance of the cascade at different Mach numbers. The simulation results show that the large enthalpy drop stationary cascade designed by HTC can offer good aerodynamic performance while keeping its high-load characteristics in the change range of outlet Mach number as stated in this paper.