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教材二次加工的情境填补、问题转化与立体设计 被引量:3
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作者 赵惠岩 《教育理论与实践》 CSSCI 北大核心 2018年第17期43-45,共3页
教材能稳定地、系统化地呈现学科知识,并有秩序地把握一门课程的目标、性质和任务,依据相关线索构建学科知识网络。而教师的课程实施过程对教材的创造性应用则是"二次加工"的过程,教师不仅要考虑教材内容,还要兼顾教材预设和... 教材能稳定地、系统化地呈现学科知识,并有秩序地把握一门课程的目标、性质和任务,依据相关线索构建学科知识网络。而教师的课程实施过程对教材的创造性应用则是"二次加工"的过程,教师不仅要考虑教材内容,还要兼顾教材预设和课堂生成的结合,恰当地运用情境填充和替换方法,将程序性教材转化为生成性教材,促使"教教材"和"用教材"相结合,从根本上动摇"理想的教材"观,通过"二次加工",转向对实践性教材的探索,以立体化设计思维增加教材的开放性、协作性及策略性。 展开更多
关键词 教材 “二次加工” 情境填补 问题转化 多模态 教材立体化设计
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Characterization of mechanical properties and microstructures of spark plasma sintered and cryo-rolled AA2024−Y composites 被引量:1
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作者 CH.S.VIDYASAGAR D.B.KARUNAKAR 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第6期1439-1451,共13页
The relationship between the microstructure and mechanical properties of the spark plasma sintered AA2024 Y composites subjected to cryo-rolling was investigated. Yttrium addition enhances the mechanical properties of... The relationship between the microstructure and mechanical properties of the spark plasma sintered AA2024 Y composites subjected to cryo-rolling was investigated. Yttrium addition enhances the mechanical properties of the composites by promoting grain refinement and precipitation. However, there is a clear trend of initial increase and later decrease in the properties. Also, it is observed that 0.3 wt.% of yttrium is the optimum amount of reinforcement content to obtain the highest mechanical properties. To further improve the tensile strength of the composites, cryo-rolling was performed on the composites under standard cryogenic conditions by several passes up to a reduction of 25%. The mechanical properties and the corresponding microstructures of composites after cryo-rolling were correlated. The SEM and TEM microstructures reveal that the samples exhibit dual size grains, i.e., nanograins are formed as sub-grains within the actual grain. Due to the grain size reduction and the increase in the dislocation density, the tensile properties are remarkably improved compared to those of the composites before cryo-rolling. The highest mechanical properties like hardness, YS and UTS are found to be 153 HV, 539 MPa and 572 MPa, respectively, with a reasonable ductility in the composite with 0.3 wt.% Y. 展开更多
关键词 secondary processing cryo-rolling NANOGRAINS yttrium addition dual size grains spark plasma sintering
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Recycling of minute metal scraps by semisolid processing:Manufacturing of design materials 被引量:3
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作者 S.SUGIYAMA T.MER A J.YANAGIMOTO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1567-1571,共5页
As a new attempt to recycle minute metal scraps, the possibility of manufacturing design materials by semisolid extrusion processing was shown.A design material with an intended shape, such as a character or petal sha... As a new attempt to recycle minute metal scraps, the possibility of manufacturing design materials by semisolid extrusion processing was shown.A design material with an intended shape, such as a character or petal shape, was manufactured using minute metal scraps.Similarly, a design material with an intended color pattern for each metal, such as red copper in a white aluminum matrix, resembling grainlike wood, was manufactured by mixing two or more types of minute metal scrap.In addition, secondary design materials, which have engraved patterns on the surface of the target metal made by an electric discharge machine using the above primary design material as an electrode, were manufactured. 展开更多
关键词 semisolid processing minute metal scraps RECYCLING design material
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