支持学习视角下,活力数学课堂的方法探析——以“不等式的性质”教学为例

本文以＂支持学习＂理论为指导,以＂不等式的性质＂这一课为例,从学生思维、课堂讨论、几何画板等角度改进和优化初中数学教学方法,以期促进学生深度地学,成就活力课堂.

活力数学,激扬生命潜能——基于活力数学课堂文化建设的实践与思考

活力数学追求的是从学生心灵发展出发,通过教师的教育智慧,创建富有生命的、有效的课堂,在生动、活泼的数学教学活动中,使学生习得数学知识,发展数学思维,提高数学能力。活力数学源于自主,自主的前提是教师对学生的尊重、信任和课堂的开放。活力数学贵在体验,通过学生自身的体验,将学习活动中的一些问题真实客观地反映出来。活力数学,重在思维,做到把握本质,发展思维;善于启迪学生的思维,激活学生的思维,从而达到深化思维的目的。

依托生活现实 构建活力数学

依托小学生生活现实,并紧扣教材内容等,科学地实施数学课堂教学,是打造高效教学的根本所在,也是构建有活力数学学习的重要抓手。所以,在小学数学教学中教师就得用好生活这一主脉,通过紧扣生活去思考、依托生活去引领、抓实生活去研究等细节来打磨,让学生在浓郁的生活气息中更有效地探究各种数学现象,探秘相应的数学规律,从而真正缔造有效学习,也让学生在学习历程中发展和提升数学经验、数学思维。

指向思维发展的“活力数学”课堂构建

笔者主张“活力数学”,其核心在于发展学生的数学思维能力和培养学生良好的数学思维品质.为此,“活力数学”应致力于营造润泽的课堂氛围,采取灵活的教与学方式,通过扎实有效的教学互动,促使学生真正参与课堂,充分彰显思维活力,关注课堂动态生成,鼓励思维创新,让课堂充满智慧与灵动,使数学课堂成为师生共同成长的生命课堂.

用尝试教学法构建活力数学课堂

如果要切实提高小学数学课堂教学效果,推动学生数学知识、数学能力、数学素养的全面发展,教师就必须坚持以学生为中心,充分调动和发挥学生学习数学的主观能动性.教师积极探索了“尝试教学法”在小学数学课堂的渗透应用,设计了尝试提出问题、尝试表达观点、尝试做出质疑、尝试辩论学习、尝试自主训练等多元化教学活动,凸显了学生在数学课堂上的主体地位,调动了学生学习数学的积极性,助力了学生数学学科核心素养的提升与发展.

以“创新”为支点,构建小学数学活力课堂

数学活力课堂的构建,有助于学生参与热情的调动,从而主动跟随教师的指导,完成相应的学习任务,最终实现学习效率的提升;有助于学生数学思维的发展,久而久之,形成良好的数学精神。基于此,文章以“创新”为支点,构建数学活力课堂的对策,从三方面,即注重预习环节的创新,促使学生高效完成预习目标;注重教学方法的创新,使学生在多元化的教学活动中形成深刻的认知;注重课后答疑方式的创新,有效改善答疑滞后的情况,进行了详细地阐述,以期能为教师完成“减负增效”目标提供一些启发。

创新数学教学模式,激活高中课堂活力

数学作为一门基础性的学科,在新形式的教学过程中一直备受关注,尤其是在高中数学教学阶段,教学内容难度系数较大,需要教师采用创新化的教学手段,进一步加强教学的力度,帮助学生更好地理解课文内容,不断提高学生的学习能力.本文将会从求异思想、合作小组模式、多媒体技术和分层教学等方面展开论述,并提供一定的参考建议.

Thermal decomposition kinetics of Algerian Tamazarte kaolinite by thermogravimetric analysis

The decomposition kinetics of Algerian Tamazarte kaolinite(TK)was investigated using thermogravimetric analysis(TG).Differential thermal analysis(DTA)and TG experiments were carried out between room temperature and1400°C,at differentheating rates from10to40°C/min.The activation energies,measured by DTG from isothermal treatments usingJohnson-Mehl-Avrami(JMA)and Ligero methods and by non-isothermal treatments using Ozawa,Boswell and Kissinger methods,were around151and144kJ/mol,respectively.The Avrami parameter of growth morphology(indicating the crystallization mode)was found to be around1.57using non-isothermal treatments;however,when using isothermal treatments it is found to be equal to1.35.The numerical factor,which depends on the dimensionality of crystal growth,is found to be1.53using Matusita equation.Thefrequency factor calculated by the isothermal treatment is equal to1.55×107s-1.The results show that the bulk nucleation is followedby three-dimensional growth of metakaolinite with polyhedron-like morphology controlled by diffusion from a constant number ofnuclei.

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.

A Novel Exponential Kinetic Model for Casein Tryptic Hydrolysis to Prepare Active Peptides

The kinetics of casein tryptic hydrolysis to prepare activepeptides was investigated. Taking into account the reaction mechanismincluding single substrate hydrolysis, irreversible enzymeinactivation, and substrate inhibition, a set of exponentialequations was established to characterize the enzymatic hydrolysiscurves. The verification was carried out by a series of experimentalresults and indicated that the average regressive error was less than5/100. According to the proposed kinetic model, the kinetic constantsand thermodynamic constants of the reaction system were alsocalculated.

Deformation features and failure mechanism of steep rock slope under the mining activities and rainfall

Underground mining activities and rainfall have potential important influence on the initiation and reactivation of the slope deformations,especially on the steep rock slope. In this paper,using the discrete element method(UDEC),numerical simulation was carried out to investigate deformation features and the failure mechanism of the steep rock slope under mining activities and rainfall. A steep rock slope numerical model was created based on a case study at the Wulong area in Chongqing city,China. Mechanical parameters of the rock mass have been determined by situ measurements and laboratory measurements. A preliminary site monitoring system has been realized,aiming at getting structure movements and stresses of unstablerock masses at the most significant discontinuities. According to the numerical model calibrated based on the monitoring data,four types of operation conditions are designed to reveal the effect of mining excavation and extreme rainfall on the deformation of the steep rock slope.

INVESTIGATION OF THE INTERACTIONS BETWEEN WATER AND MODIFIED SILICA GEL BY IGC AND TPD

In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatography （IGC） in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption （TPD） technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.

Pyrolysis Characteristics and Kinetics of the Preparation Process of Sludge-Based Activated Carbon by ZnCl_2 Activation Method

To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method （i.e.the pyrolysis process of the sludge with ZnCl2 activation）,the characteristic of mass loss and gas products generated during pyrolysis of the sludge with ZnCl2 activation were analyzed by thermogravimetric analysis coupled with Fourier Transform Infrared Spectroscopy （TG-FTIR）.The kinetic parameters were calculated by the Coats-Redfem method and the mechanism models were established.The role of ZnCl2 in the pyrolysis process of the sludge with ZnCl2 activation was also illustrated through the comparison of the pyrolysis characteristics and kinetics of the sludge with and without ZnCl2 activation.The results showed that the pyrolysis process of the sludge with ZnCl2 activation can be divided into four stages including the dehydration of sludge and initial depolymerization of a small portion of organics matters,the decomposition of large molecular organic matters into small molecular intermediates,the further degradation of intermediates and volatilization of ZnCl2,and the decomposition of inorganic minerals and undecomposed organic matters.CO2,CO,CH4,H2O,some aldehydes and carboxylic acids are the major pyrolysis gaseous products.The activation energies and pre-exponential factors are in the range of 28.84-206.42 kJ/mol and 9885.16-8.08× 1011 min-1,respectively.During the pyrolysis of sludge,ZnC12 not only can function as a dehydration agent and inhibit the formation of tar,but also can peptize the organic matters in the sludge,making them easier to be decomposed.

Oxygen pressure acid leaching of artificial sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation

The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.

Adsorption and desorption properties of D318 resin for Cr(Ⅵ)

The adsorption capability of D318 resin for Cr（Ⅵ） was investigated by chemistry analysis. Experimental results show that D318 resin has the best adsorption ability for Cr（Ⅵ） at pH=3.16 in HAc-NaAc medium. The statically saturated adsorption capacity of the resin is 265.4 mg/g. The thermodynamic adsorption parameters, enthalpy change AH and free energy change AG298 of the adsorption reaction are 4.81 and -5.16 kJ/mol, respectively. The apparent activation energy Ea is 22.4 kJ/mol. The adsorption behavior obeys the Freundlich isotherm. The molar coordination ratio of the functional group of resin to Cr（Ⅵ） is 3：2. Cr（Ⅵ） adsorbed on D318 resin can be eluted by 5%NaOH-5%NaCl quantitatively.

增强小学数学课堂教学活力的“两因素”

在小学数学教学中，活力是一个非常重要的影响因素。简单来说，活力能提高小学数学的教学质量，让学生在学习过程中收获更多的知识。更好地促进自身综合素质的发展和进步。

Bioregeneration of spent activated carbon:Review of key factors and recent mathematical models of kinetics

The disposal of spent activated carbon(AC) will inevitably create secondary pollution. In overcoming this problem, the spent AC can be regenerated by means of biological approach. Bioregeneration is the phenomenon in which through the action of microorganisms, the adsorbed pollutants on the surface of the AC will be biodegraded and this enables further adsorption of pollutants to occur with time elapse. This review provides the challenges and perspectives for effective bioregeneration to occur in biological activated carbon(BAC)column. Owing to very few reported works on the bioregeneration rate in BAC column, emphasis is put forward on the recently developed models of bioregeneration kinetic in batch system. All in all, providing potential solutions in increasing the lifespan of AC and the enhancement of bioregeneration rate will definitely overcome the bottlenecks in spent AC bioregeneration.

An evaluation equation of TG experiment data based on iso-conversion method for activation energy

The iso-conversion method to could calculate the kinetics parameters effectively, the present paper built an evaluation equation for iso-conversion methods according to the thermo kinetics integral equation and analyses the temperatures of the same degree of conversion for different heating rates by ideal TG （thermo-gravity） curve data. It is obtained that the temperatures of the same degree of conversion for different heating rates＇ TG curve have good linearity connection validating the correction of the evaluation equation for iso-conversion methods and the scope of linear slope for theratio between heating rates being 2 is 1.05 to 1.09.

Local Structure and Dynamics Procedure of Impurities Fe,Al and Mn in Melt Beryllium

The local structure and dynamics of impurities Fe,Al and Mn in beryllium were investigated on an atomic scale using ab initio molecular dynamics and statistical physics methods.The analysis of the radial distribution function centered on impurity atoms shows that the density of beryllium atoms around Fe and Mn is 8.4%and 8.6%higher than that around Al,respectively.The statistics of the measure square displacement of impurity atoms show that the diffusion coefficients of Al atoms are 114%and 133%larger than that of Fe and Mn atoms in the melt beryllium,respectively.Statistical analysis of velocity autocorrelation function of impurity atom shows that Fe and Mn atoms collide strongly with beryllium atoms in the first coordination layer,indicating that they are tightly surrounded and bound by the surrounding beryllium atoms in the central position,while the beryllium atoms around Al are loosely arranged and have weak binding forces with Al.The analysis of the activity coefficients of the impurities shows that when Fe or Mn enters the melt beryllium,it reduces the free energy of the system,whereas when Al enters,it increases the system energy.In summary,the interatomic force of BeAl is weak,so they do not form intermetallic compounds,and Al diffuses quickly in beryllium.While BeFe and BeMn have strong interatomic forces,and tend to form more BeFe and BeMn bonds to reduce the free energy of the system,so Fe and Mn diffuse slowly in beryllium.Ab initio molecular dynamics can be used to forecast the best experimental temperature for the vacuum distillation of beryllium.

Kinetic study on desulfurization and denitrification using microwave irradiation over activated carbon

Sulfur dioxide （SO2） and nitrogen oxide （NOx） in flue gas can be removed by combining microwave induced catalysis and adsorption on activated carbon. The reaction mechanisms of desulfurization and denitrification by microwave irradiation were analyzed based on the measurement of reaction products. Thermodynamic parameters for desulfurization and denitrification by thermal-carbon reduction were predicted according to the principles of thermodynamics. The experimental results indicated that the desulfurization and denitrification reaction processes include three reaction stages： slow reaction zone, transitional zone and rapid reaction zone. In high temperature zone, activation energies for the reduction of SO2 and nitrogen monoxide （NO） are 30.69 and 24.06 kJ mo1-1, respectively. This study shows that microwave can effectively enhance the removal of pollutants through its heating effect and the induced catalysis.