学力结构论初探

国内外60年来的学力研究囿于"应然"视觉的观念性、假想性和抽象性,21世纪的学力研究应当从"实然"视角去探究学力的有机系统性与生长过程性,从而构建出系统的、生态的学力结构模型。根据这一研究理念考察了个体的终身发展的学力结构,为各阶段教育的贯通与定位,学教合力的形成等提供了规律性认识。

《学力结构与教育评价》——一本令人思考的好书

日本教育方法学会编辑的《学力结 构与教育评价》一书,论述了当前日本 社会对学生能力的看法和激励学生奋进 的行之有效的教育评价方法。本书共分 三章九节: 第一章 “学力与评价”

日本新学习指导要领与学力结构研究的深化——访日本课程学会理事长水原克敏

2009年7月笔者参加了日本课程学会20周年大会,访问了新任课程学会理事长、东北大学教授水原克敏,与教授就日本新学习指导要领的定位、从课程改革历史看课程改革的发展、PISA调查的概念结构与学力结构研究的深化以及对课程实施的影响等问题进行了访谈。

现代学力的结构及其评价原则

随着现代教育的发展,学力评价问题已引起了社会各界的普遍重视,学力评价也成了教育评价的重点研究课题之一。现代学力观具有以下一些特点: 现代学力观重视学生的全面发展。学力的概念不仅指与学科知识有关的能力,而是指学生在思想品德、知识技能、体质、社会适应,以及劳动知能等各个方面的可教育性及实际发展水平。从心理学角度讲,它包括一个人个性的各个方面;从教育学的角度讲,它包括德、

生态学力论

20世纪的学力研究教训表明,21世纪的学力研究视点需要三个转移,一是从以"教"为中心转移到以"学"为中心,二是从静态的抽象分析转移到动态的生态考察,三是从中小学基础教育阶段的研究转移到学习者的终身学习上来。文章从"学"的角度来重新讨论"学力"问题,以生态学、终身学习理论、建构主义学习理论和系统论为指导,论述了学力构成的五大要素及其发展形态,提出了生态学力观的基本构想。

以学力培养为核心的基础教育改革初探

随着升学考试压力的加大,贯彻落实素质教育,解决由应试教育所导致的厌学、逃学等问题,必须加强对学生学习的引导。教育引导学习的关键在于培养提升"学力",基础教育改革应以学力培养为核心,充分发挥学生的主动性和能动性,引导学生积极主动地参与学习,让学生的身心真正地回到课堂,促使学生的学力不断地优化完善。

关于中学数学学力评价的探讨

本文论述了学力及学力评价的概念,结合我国中学数学教育的特点和实际,强调了学力评价的重要意义,指出在中学数学教育的学力评价中存在的一些问题,并对学力的结构进行了探讨。

Characteristic and optimization of ferrite-rich sulfoaluminate-based composite cement suitable for cold region tunnels

To develop suitable grouting materials for water conveyance tunnels in cold regions,firstly,this study investigated the performance evolution of ferrite-rich sulfoaluminate-based composite cement(FSAC grouting material)at 20 and 3℃.The results show that low temperature only delays the strength development of FSAC grouting material within the first 3 d.Then,the effect of four typical early strength synergists on the early properties of FSAC grouting material was evaluated to optimize the early(£1 d)strength at 3℃.The most effective synergist,Ca(HCOO)_(2),which enhances the low-temperature early strength without compromising fluidity was selected based on strength and fluidity tests.Its micro-mechanism was analyzed by XRD,TG,and SEM methods.The results reveal that the most suitable dosage range is 0.3 wt%−0.5 wt%.Proper addition of Ca(HCOO)_(2)changed the crystal morphology of the hydration products,decreased the pore size and formed more compact hydration products by interlocking and overlapping.However,excessive addition of Ca(HCOO)_(2)inhibited the hydration reaction,resulting in a simple and loose structure of the hydration products.The research results have reference value for controlling surrounding rock deformation and preventing water and mud inrushes during the excavation in cold region tunnels.

Time-dependent effects in transient liquid phase bonding of 304L and Cp-Ti using an Ag-Cu interlayer

One of the challenges for bimetal manufacturing is the joining process.Hence,transient liquid phase(TLP)bonding was performed between 304L stainless steel and Cp-Ti using an Ag-Cu interlayer with a thickness of 75μm for bonding time of 20,40,60,and 90 min.The bonding temperature of 860℃ was considered,which is under the β transus temperature of Cp-Ti.During TLP bonding,various intermetallic compounds(IMCs),including Ti_(5)Cr_(7)Fe_(17),(Cr,Fe)_(2)Ti,Ti(Cu,Fe),Ti_(2)(Cu,Ag),and Ti_(2)Cu from 304L toward Cp-Ti formed in the joint.Also,on the one side,with the increase in time,further diffusion of elements decreases the blocky IMCs such as Ti_(5)Cr_(7)Fe_(17),(Cr,Fe)_(2)Ti,Ti(Cu,Fe)in the 304L diffusion-affected zone(DAZ)and reaction zone,and on the other side,Ti_(2)(Cu,Ag)IMC transformed into fine morphology toward Cp-Ti DAZ.The microhardness test also demonstrated that the(Cr,Fe)_(2)Ti+Ti_(5)Cr_(7)Fe_(17) IMCs in the DAZ on the side of 304L have a hardness value of HV 564,making it the hardest phase.The maximum and minimum shear strength values are equal to 78.84 and 29.0 MPa,respectively.The cleavage pattern dominated fracture surfaces due to the formation of brittle phases in dissimilar joints.

学商LQ

学商反映的主要是人的成长阶段学力水平与年龄的关系。学力的概念是指自我教育力或自我学习力。学力的结构可以分解为 :选择系统、接受系统、加工系统、记忆储存系统、动力系统和管理系统。提高学商有三个基本原理 :最优原理 ;志向原理 ;

谈谈学法指导的意义

谈谈学法指导的意义沈绍辉中学语文教学大纲指出，要“指导学生掌握科学的学习方法，培养良好的学习习惯，提高自学能力”。这是语文教师义不容不辞的重要职责。本文仅就学法指导的意义谈几点粗浅的看法。现代教学理论认为，教学方法包括教的方法和学的方法。正如前苏联教...

Molecular dynamics simulation of relationship between local structure and dynamics during glass transition of Mg_7Zn_3 alloy

The rapid solidification process of Mg7Zn3 alloy was simulated by the molecular dynamics method. The relationship between the local structure and the dynamics during the liquid-glass transition was deeply investigated. It was found that the Mg-centered FK polyhedron and the Zn-centered icosahedron play a critical role in the formation of Mg7Zn3 metallic glass. The self-diffusion coefficients of Mg and Zn atoms deviate from the Arrhenius law near the melting temperature and then satisfy the power law. According to the time correlation functions of mean-square displacement, incoherent intermediate scattering function and non-Gaussian parameter, it was found that the β-relaxation in Mg7Zn3 supercooled liquid becomes more and more evident with decreasing temperature, and the α-relaxation time rapidly increases in the VFT law. Moreover, the smaller Zn atom has a faster relaxation behavior than the Mg atom. Some local atomic structures with short-range order have lower mobility, and they play a critical role in the appearance of cage effect in theβ-relaxation regime. The dynamics deviates from the Arrhenius law just at the temperature as the number of local atomic structures begins to rapidly increase. The dynamic glass transition temperature （Tc） is close to the glass transition point in structure （TgStr）.

Hydrogen storage kinetics of nanocrystalline and amorphous Cu-Nd-added Mg_2Ni-type alloys

The(Mg24Ni10Cu2)100-x Nd x(x=0, 5, 10, 15, 20) alloys with nanocrystalline and amorphous structures were prepared by melt spinning technology. The structures of the as-cast and spun alloys were characterized by X-ray diffraction(XRD) and high resolution transmission electron microscopy(HRTEM). The effects of Nd content and spinning rate on the structures and hydrogen storage kinetics of the alloys were investigated. The results show that the as-spun Nd-free alloy displays an entire nanocrystalline structure, whereas the as-spun Nd-added alloys hold nanocrystalline and amorphous structures, suggesting that the addition of Nd facilitates the glass forming of the alloys. Both the Nd-addition and the melt spinning significantly improve the gaseous and electrochemical hydrogen storage kinetics of the alloys. The addition of Nd and melt spinning enhance the diffusion ability of hydrogen atoms in the alloy, but both of them impair the charge-transfer reaction on the surface of the alloy electrode, which makes the high rate discharge ability(HRD) of the alloy electrode first mount up and then go down with the growing Nd content and spinning rate.

Local structure of calcium silicate melts from classical molecular dynamics simulation and a newly constructed thermodynamic model

The distributions of local structural units of calcium silicate melts were quantified by means of classical molecular dynamics simulation and a newly constructed structural thermodynamic model. The distribution of five kinds of Si-O tetrahedra Qi from these two methods was compared with each other and also with the experimental Raman spectra, an excellent agreement was achieved. These not only displayed the panorama distribution of microstructural units in the whole composition range, but also proved that the thermodynamic model is suitable for the utilization as the subsequent application model of spectral experiments for the thermodynamic calculation. Meanwhile, the five refined regions mastered by different disproportionating reactions were obtained. Finally, the distributions of two kinds of connections between Qi were obtained, denoted as Qi-Ca-Qj and Qi-[Ob]-Qj, from the thermodynamic model, and a theoretical verification was given that the dominant connections for any composition are equivalent connections.

Mechanical properties and pore structure deformation behaviour of biomedical porous titanium

Porous titanium has been shown to exhibit desirable properties as biomedical materials. In view of the load-bearing situation, the mechanical properties and pore structure deformation behaviour of porous titanium were studied. Porous titanium with porosities varying from 36%-66% and average pore size of 230 μm was fabricated by powder sintering. Microstructural features were characterized using scanning electron microscopy. Uniaxial compression tests were used to probe the mechanical response in terms of elastic modulus and compressive strength. The mechanical properties of porous titanium were found to be close to the those of human bone, with stiffness values ranging from 1.86 to 14.7 GPa and compressive strength values of 85.16-461.94 MPa. The relationships between mechanical properties and relative densities were established, and the increase in relative density showed significant effects on mechanical properties and deformations of porous titanium. In a lower relative density, the microscopic deformation mechanism of porous titanium was yielding, bending and buckling of cell walls, while the deformation of yielding and bending of cell walls was observed in the porous titanium with higher relative density.

Mechanical properties and electronic structures of MgCu_2, Mg_2Ca and MgZn_2 Laves phases by first principles calculations

Mechanical properties and electronic structure of MgCu2, Mg2 Ca and MgZn2 phases were investigated by means of first principles calculations from CASTEP program based on density functional theory（DFT）. The calculated lattice parameters are in good agreement with the experimental and literature values. The calculated heat of formation and cohesive energies showed that MgCu2 has the strongest alloying ability and structural stability. Elastic constants of MgCu2, Mg2 Ca and MgZn2 were calculated, and the bulk moduli, shear moduli, elastic moduli and Poisson ratio were derived. The calculated results show that MgCu2, Mg2 Ca and MgZn2 are all ductile phases. Among the three phases, MgCu2 has the strongest stiffness and the plasticity of MgZn2 phase is the best. Melting points of the three phases were predicted using cohesive energy and elastic constants. Density of states（DOS）, Mulliken population, electron occupation number and charge density difference were discussed. Finally, Debye temperature was calculated and discussed.

Structure and mechanical properties of thick Cr/Cr_2N/CrN multilayer coating deposited by multi-arc ion plating

A Cr/Cr2N/CrN multilayer coating with a thickness of 24.4 μm was deposited by multi-arc ion plating. The coating was systematically characterized by field emission scanning electron microscopy(FESEM), X-ray photoelectron spectrometry(XPS), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD) and transmission electron microscopy(TEM). Hardness and adhesion were tested by nanoindentation and scratch tester, respectively. The friction properties were investigated by a reciprocating UMT-3MT ball-on-disk tribometer in air and seawater. The results showed that the multilayer coating consisted of three different layers, with Cr,Cr2N and CrN phases, respectively. Compared with CrN single layer coating, the adhesion of the multilayer coating was improved significantly, the hardness of the multilayer coating was(21±2) GPa. The corrosion resistance of the multilayer coating was also improved in artificial seawater. The friction coefficient of multilayer coating was lower than that of CrN single layer coating both in air and seawater.

Failure mechanism of as-cast Mg-6Zn-2Er alloy during tensile test at room temperature

Tensile test of the as-cast Mg-6Zn-2Er alloy was conducted at room temperature. The results indicate that the alloy is inclined to failure when the strain reaches 5.6%. The coarse secondary phases are responsible for the failure, especially for the Mg3Zn3Er2 phase （W-phase）. It is indicated that the existence of the W-phase activates the stress concentrations due to the incapacity of W-phase for the load transfer, which results in the void at the inner of the W-phase. In comparison, the interface between the matrix and the secondary phase is stable. In conclusion, the characters of the secondary phases with respect to size, distribution, morphology and type, play an important role in the plastic deformation behavior of the alloy.