自带设备(Bring Your Own Device,BYOD)的广泛应用为打造"人人皆学、处处能学、时时可学"的学习体系提供了条件。文章在自带设备的信息化环境下,基于自我效能等理论,构建了高校"4S"教学模型,并通过内容分析法、问...自带设备(Bring Your Own Device,BYOD)的广泛应用为打造"人人皆学、处处能学、时时可学"的学习体系提供了条件。文章在自带设备的信息化环境下,基于自我效能等理论,构建了高校"4S"教学模型,并通过内容分析法、问卷调查法等研究方法检验了教学模型的有效性,结果显示BYOD支撑下"4S"教学模型对学习者的信息搜索、问题解决、合作探究等21世纪必备学习能力的提高有一定促进作用。展开更多
A unified constitutive model is presented to predict the recently observed“multi-stage”creep behavior of Al−Li−S4 alloy.The corresponding microstructural variables related to the yield strength and creep deformation...A unified constitutive model is presented to predict the recently observed“multi-stage”creep behavior of Al−Li−S4 alloy.The corresponding microstructural variables related to the yield strength and creep deformation of the alloy during the creep ageing process,including dislocations and multiple precipitates,have been characterized in detail by X-ray diffraction(XRD)and transmission electron microscopy(TEM).For the yield strength,the model considers the multiphase strengthening behavior of the alloy based on strengthening mechanisms,which includes shearable T1 precipitate strengthening,non-shearable T1 precipitate strengthening andθ′precipitate strengthening.Based on creep deformation mechanism,the“multi-stage”creep behavior of the alloy is predicted by introducing the effects of interacting microstructural variables,including the radius of multiple precipitates,dislocation density and solute concentration,into the creep stress−strain model.It is concluded that the results calculated by the model are in a good agreement with the experimental data,which validates the proposed model.展开更多
文摘自带设备(Bring Your Own Device,BYOD)的广泛应用为打造"人人皆学、处处能学、时时可学"的学习体系提供了条件。文章在自带设备的信息化环境下,基于自我效能等理论,构建了高校"4S"教学模型,并通过内容分析法、问卷调查法等研究方法检验了教学模型的有效性,结果显示BYOD支撑下"4S"教学模型对学习者的信息搜索、问题解决、合作探究等21世纪必备学习能力的提高有一定促进作用。
基金the National Key R&D Program of China(No.2017YFB0306300)the National Natural Science Foundation of China(Nos.51675538,51601060)+1 种基金the State Key Laboratory of High-performance Complex Manufacturing,China(No.ZZYJKT2018-18)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2018zzts151).
文摘A unified constitutive model is presented to predict the recently observed“multi-stage”creep behavior of Al−Li−S4 alloy.The corresponding microstructural variables related to the yield strength and creep deformation of the alloy during the creep ageing process,including dislocations and multiple precipitates,have been characterized in detail by X-ray diffraction(XRD)and transmission electron microscopy(TEM).For the yield strength,the model considers the multiphase strengthening behavior of the alloy based on strengthening mechanisms,which includes shearable T1 precipitate strengthening,non-shearable T1 precipitate strengthening andθ′precipitate strengthening.Based on creep deformation mechanism,the“multi-stage”creep behavior of the alloy is predicted by introducing the effects of interacting microstructural variables,including the radius of multiple precipitates,dislocation density and solute concentration,into the creep stress−strain model.It is concluded that the results calculated by the model are in a good agreement with the experimental data,which validates the proposed model.