初中数优生、数困生的数学学习投入研究

通过对208名初中数优生、数困生的问卷调查,考察两类初中生数学学习投入的特点及其影响因素。结果表明：（1）数困生的数学学习投入显著低于数优生;数优生与数困生的数学学习投入有不同的变化趋势：数优生的学习投入一直维持在较高水平,而数困生的学习投入随年级的升高在逐渐下降;数困生的情感投入水平比认知投入、行为投入更低;数学学习投入的性别差异不显著。（2）社会支持、数学观和数学自我效能感对数优生、数困生的数学学习投入均具有显著影响;社会支持对数学学习投入既具有直接影响,同时也具有间接影响;数学观和数学自我效能感在社会支持和数学学习投入之间起着中介作用。     

溶液表面吸附实验拓展

对经典的物理化学实验"溶液表面吸附的测定"进行了拓展,将体系由单一的正丁醇溶液扩展成正丁醇、异丁醇和叔丁醇一系列同分异构体。分别测定了3种醇溶液在不同浓度下的表面张力,拟合实验数据进而计算得到了单分子的占有面积,并与chem3D软件的理论模拟进行了比较。结果表明,实验求得吸附量和单分子占有面积的同时,可以有效地区分分子纳米尺度的结构差异。实验有助于增强学生对微观的具象认识,并对表面吸附实验有更加深刻全面的理解。     

Technologizing Numeracy: Intergenerational Differences in Working Mathematically in New Times

Literacy educators have been actively theorising the demands of literacy in New Times yet mathematics educators have taken little of this debate up. If, as literacy educators suggest, literacy demands are different in these New Times, what are the implications for numeracy or mathematics educators? This paper explores perceptions of young and older people who are engaged in work practices. It was found that there were statistically significant differences in a number of areas. Numeracy was found to be an important variable in discerning differences between older and younger people, and that technology was also seen to differentiate the two cohorts. Within numeracy, older people were more like to see number as important, whereas younger people were more likely to identify statistics, applied areas of mathematics and the use of technology to support numeracy as being important. These finding shave implications for theorising and practice in mathematics education.     

五年制师范数学学困生非智力因素的调查研究

本文通过问卷调查方式对五年制师范艺术教育、学前教育专业学困生的数学学习态度、兴趣、预期和自我评价等方面作出初步研究,并提出相应的教学转化策略。     

美国数学教育改革与数学天赋学生培养的简略回顾--如何在鱼腹中发现珍珠

数学天赋教育是数学教育改革的重要分支，美国最近20多年的数学教育改革提供了关于数学天赋教育的有价值的经验，天才班并不是培养数学天赋学生的唯一选择，数学教师必须努力在一般课堂中识别数学天赋学生并开发他们的潜能；必须学会运用基本的策略来调整课堂教学以提高对天赋学生教学的能力；必须逐步建立自己的信念，调整自己的知识结构来培养数学天赋学生。     

英国数学英才教育的实证研究及对我国的启示——基于英国三所中学数学英才学生的问卷调查

英国是世界上公认的重视英才教育的国家,而且其英才教育的理念、培养和评价等教育体系比较成熟。通过对英国三所中学的141名数学英才学生进行问卷调查、个别访谈,结果表明:英国数学英才学生"痴迷"数学,"钟情"创新;数学知识获取方式和学习方式多元化;学习自我效能感高;英才身份认同感强。这些对我国的数学英才教育具有一定的借鉴意义。     

On modeling and analyzing multi-agent systems using n-calculus

Dynamic architecture of multi-agent systems （MAS） is important for critical systems. As the existing formal specifications of MAS cannot describe its dynamic architecture, a formal approach using n-calculus is presented, which is suited for the describing and analyzing of concurrent MAS with dynamic topology, n-calculus describes the belief-desireintention （BDI） model that represents agent＇s mental states and provides many useful facilities to analyze MAS model such as deadlock, behavior equivalence, and model checking. To illustrate the favorable representation capability of n-calculus, an example of dynamic multi-agent systems in e-commerce is provided. Finally, by using an existing n-calculus supporting tool, MAS model and some key behaviors properties are analyzed and verified.     

Teaching and Learning in STEM Enrichment Spaces: From Doing Math to Thinking Mathematically

Science, technology, engineering, and mathematics (STEM) enrichment programs can meet the needs of gifted students by providing an intellectual challenge, a motivated peer group, and skilled teachers. In the Saturday Enrichment Program (SEP), 40 students (Grades 4–8) explored challenging math topics not typically taught in their schools. Pre and post questionnaires, video documentation of classes, and field notes indicated that students were less interested in the content of their school math classes after participation in SEP. They also reported that SEP provided a more appropriate pace, challenge, and fun. Analysis of classroom videos revealed four major strategies teachers utilized: (a) fostering of a supportive and collaborative environment, (b) developing the identity of a mathematician, (c) open-ended questions for conceptual exploration, and (d) discovery through play.     

基于π演算的多agent系统建模与分析

Dynamic architecture of multi-agent systems (MAS) is important for critical systems. As the existing formal specifications of MAS cannot describe its dynamic architecture, a formal approach using π-calculus is presented, which is suited for the describing and analyzing of concurrent MAS with dynamic topology. π-calculus describes the belief-desireintention (BDI) model that represents agent's mental states and provides many useful facilities to analyze MAS model such as deadlock, behavior equivalence, and model checking. To illustrate the favorable representation capability of π-calculus, an example of dynamic multi-agent systems in e-commerce is provided. Finally, by using an existing π-calculus supporting tool,MAS model and some key behaviors properties are analyzed and verified.     

Improved modeling of intelligent tutoring systems using ant colony optimization

Swarm intelligence approaches, such as ant colony optimization (ACO), are used in adaptive e-learning systems and provide an effective method for finding optimal learning paths based on self-organization. The aim of this paper is to develop an improved modeling of adaptive tutoring systems using ACO. In this model, the learning object is personalized based on learning and solving problem styles. The purposed algorithm, based on ACO, generates the adaptive optimal learning path. The algorithm describes an architecture which supports the recording, processing and presentation of collective learner behavior designed to create a feedback loop informing learners of successful paths towards the attainment of learning goals. The algorithm parameters are tuned dynamically to conform to the actual pedagogical process. The article includes the results of implementation and experiment represent this algorithm is able to provide its main purpose which is finding optimal learning paths based on learning styles and improved performance of previous adaptive tutoring systems.     

初中数优生、数困生解题动机与应用题成绩的关系分析

采用数学应用题测验和解题动机问卷对筛选出的391名初中生进行测试,结果表明:①初中生数学应用题成绩的性别差异不显著;②数优生、数困生在数学解题动机上存在显著差异(p<0.05);③解题动机对数学应用题成绩具有预测作用(R2=0.076,B=1.127).     

Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

The partition behaviors of β-1,3-1,4-glucanase, α-amylase and neutral proteases from clarified and whole fermentation broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system (polyethylene glycol (PEG)/MgSO4)was examined with regard to the effects of PEG molecular weight (MW) and concentration, MgSO4 concentration, pH and NaCl concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of β-glucanase with the PEG/MgSO4 system. MgSO4 concentration influenced the partition and extraction of β-glucanase significantly. pH had little effect on β-glucanase or proteases partition but affected α-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of β-glucanase but had very significant effects on the partitioning of α-amylase and on the neutral proteases. The partition behaviors of β-glucanase, α-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying β-glucanase was developed, which achieved β-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.     

固体碱催化固定床法生产生物柴油的工艺研究(英文)

对固体碱催化剂催化固定床法工业化生产生物柴油进行了模拟.顺利进行了小试实验,并建立了生物柴油合成的酯交换反应的动力学模型,该模型能较为准确地描述酯交换反应.通过对文献中的气液平衡数据的回归得到了生物柴油的安托因方程.选择NRTL模型对脂肪酸甲酯(FAME)-甲醇-甘油体系进行描述,得到了体系NRTL的二组分参数,利用Aspen Plus对该体系液液平衡数据(LLE)的回归得到了三组分相图.为了预测固定床工艺生产在工业规模放大1 000倍后的效果,Aspen Plus对2个流程进行了仿真模拟,预测物料和能量消耗.模拟结果表明,与先前文献报道的数据相比,每小时生产每吨生物柴油至少可以减少350.42 kW的能量消耗.     

Experimental adsorption equilibrium study and comparison of zeolite with water and ethanol for cooling systems

INTRODUCTION In the past few decades, adsorption processes have been used exclusively for gas separation and purification purposes. It is only recently that this phenomenon has been exploited to produce cooling and heating. As regulations aiming at phasing out the CFCs are being implemented, thermally driven sorp-tion refrigeration machines are emerging as an at-tractive alternative to electrical vapor compression machines that produce no harmful effect on the en-vironment since their w…     

An integrated approach for modeling and solving the scheduling problem of container handling systems

INTRODUCTION Worldwide container trade has grown 9.5% per year last decade and will continue to do so at an 8% growth rate in the coming years (James et al., 1997), so container terminals have to handle containers more efficiently. Fig.1 shows a typical container terminal layout composed of “Quayside area” and “Storage yard”. Many optimization problems associated with a container terminal have been extensively studied in the past few years. Vis and De Koster (2003) gave a comprehens…     

Quasi 1D modeling of two-phase flow and deposit formation for urea-selective catalytic reduction systems

A quasi 1D model of two-phase flow for a urea-selective catalytic reduction (SCR) system is developed which can calculate not only the generation of reducing agent but also the formation of deposits in the exhaust pipe. The gas phase flow is solved through Euler method, variables are stored on staggered grids, and the semi-implicit method for pressure-linked equation (SIMPLE) algorithm is applied to decouple the pressure and velocity. The liquid phase is treated in a Lagrangian way, which solves the equations of droplet motion, evaporation, thermolysis, and spray wall interaction. A combination of a direct decomposition model and a kinetic model is implemented to describe the different decomposition behaviors of urea in the droplet phase and wall film, respectively. A new 1D wall film model is proposed, and the equations of wall film motion, evaporation, thermolysis, and species transport are solved. The position, weight, and components of deposits can be simulated following implementation of the semi-detailed kinetic model. The simulation results show that a decrease in the exhaust temperature will increase the wall film region and the weight of deposits. Deposit components are highly dependent on temperature. The urea-water-solution (UWS) injection rate can affect the total mass of wall film and expand the film region, but it has little influence on deposit components. An increase in exhaust mass flow can decrease the total weight of deposits on the pipe wall because of the promotion of the mass and heat transfer process both in the droplets and wall film.     

Critical review in adsorption kinetic models

Adsorption is one of the most widely applied techniques for environmental remediation. Its kinetics are of great significance to evaluate the performance of a given adsorbent and gain insight into the underlying mechanisms. There are lots of references available concerning adsorption kinetics, and several mathematic models have been developed to describe adsorption reaction and diffusion processes. However, these models were frequently employed to fit the kinetic data in an unsuitable or improper manner. This is mainly because the boundary conditions of the associated models were, to a considerable extent, ignored for data modeling. Here we reviewed several widely-used adsorption kinetic models and paid more attention to their boundary conditions. We believe that the review is of certain significance and improvement for adsorption kinetic modeling.     

细说氯水

1 氯水中的化学成份 氯水(指新制氯水)是一种成份比较复杂的混合物,其化学成份及微粒之间数目多少关系以及表现出的特征性质如下.