针对课程设计中目标、教学活动与测评三者的一致性评价问题,用布卢姆教育目标分类学(Bloom’s Taxonomy of Educational Objectives,BTEO)分析课程设计的各个要素。首先介绍BTEO的体系结构;接着以工程图学课程为例,阐述基于BTEO的课程...针对课程设计中目标、教学活动与测评三者的一致性评价问题,用布卢姆教育目标分类学(Bloom’s Taxonomy of Educational Objectives,BTEO)分析课程设计的各个要素。首先介绍BTEO的体系结构;接着以工程图学课程为例,阐述基于BTEO的课程设计分析方法与步骤,包括目标分类、教学活动分类与测评分类;最后论述一致性判别的方法。展开更多
We study two families of two-dimensional bright lattice solitons in photovoltaic-photorefractive crystals.It is shown that self-focusing and self-defocusing lattice solitons are possible only when their power level ex...We study two families of two-dimensional bright lattice solitons in photovoltaic-photorefractive crystals.It is shown that self-focusing and self-defocusing lattice solitons are possible only when their power level exceeds a critical threshold.It is found that self-focusing lattice solitons exist not only in the semi-infinite band gap,but also in the first band gap,whereas self-defocusing lattice solitons exist only in the first band gap.The structures of these lattice solitons are also analyzed.Our results indicate that a self-focusing lattice soliton in the semi-infinite band gap is more confined than in the first band gap so its tails in the first band gap occupy many lattice sites;when a self-defocusing lattice soliton is close to the second band,the self-defocusing lattice soliton is more confined so its tails occupy a few lattice sites.展开更多
The theory of the screening-photovoltaic solitons is improved in biased photorefractive-photovoltaic crystals.When the photovoltaic effect is negligible,the screening-photovoltaic solitons are the screening ones,and t...The theory of the screening-photovoltaic solitons is improved in biased photorefractive-photovoltaic crystals.When the photovoltaic effect is negligible,the screening-photovoltaic solitons are the screening ones,and their space-charge field is the space-charge field of the screening solitons.If the external field is absent,the screening-photovoltaic solitons are the photovoltaic ones on the open-and closed-circuit conditions,and their space-charge field is of the photovoltaic solitons.We also show theoretically that the screening and the photovoltaic solitons on the open-and closed-circuit conditions may be studies together as the screening-photovoltaic solitons.展开更多
The intensity response of an optically erased photorefractive two-wave mixing to the erase beam is studied by using the coupling wave equation and the band-transport model.The concepts of response strength and the min...The intensity response of an optically erased photorefractive two-wave mixing to the erase beam is studied by using the coupling wave equation and the band-transport model.The concepts of response strength and the minimum response intensity are introduced and their temperature dependence is investigated.A 2-fold increase in the response strength and 4-fold decrease in minimum response intensity have been experimentally observed in Ce:KNSBN at 633 nm when the crystal temperature is raised from 320 to 370K.These experimental results are in agreement with theoretical analysis and show that the response property can be improved by changing the crystal temperature.展开更多
文摘针对课程设计中目标、教学活动与测评三者的一致性评价问题,用布卢姆教育目标分类学(Bloom’s Taxonomy of Educational Objectives,BTEO)分析课程设计的各个要素。首先介绍BTEO的体系结构;接着以工程图学课程为例,阐述基于BTEO的课程设计分析方法与步骤,包括目标分类、教学活动分类与测评分类;最后论述一致性判别的方法。
基金Supported by the National Natural Science Foundation of China(No 10674176).
文摘We study two families of two-dimensional bright lattice solitons in photovoltaic-photorefractive crystals.It is shown that self-focusing and self-defocusing lattice solitons are possible only when their power level exceeds a critical threshold.It is found that self-focusing lattice solitons exist not only in the semi-infinite band gap,but also in the first band gap,whereas self-defocusing lattice solitons exist only in the first band gap.The structures of these lattice solitons are also analyzed.Our results indicate that a self-focusing lattice soliton in the semi-infinite band gap is more confined than in the first band gap so its tails in the first band gap occupy many lattice sites;when a self-defocusing lattice soliton is close to the second band,the self-defocusing lattice soliton is more confined so its tails occupy a few lattice sites.
基金Supported by the Chinese National Nature Sciences Foundation(Grant No.69978019)the State Key Laboratory Foundation of Transient Optics Technology(Grant No.YAK20006)。
文摘The theory of the screening-photovoltaic solitons is improved in biased photorefractive-photovoltaic crystals.When the photovoltaic effect is negligible,the screening-photovoltaic solitons are the screening ones,and their space-charge field is the space-charge field of the screening solitons.If the external field is absent,the screening-photovoltaic solitons are the photovoltaic ones on the open-and closed-circuit conditions,and their space-charge field is of the photovoltaic solitons.We also show theoretically that the screening and the photovoltaic solitons on the open-and closed-circuit conditions may be studies together as the screening-photovoltaic solitons.
文摘The intensity response of an optically erased photorefractive two-wave mixing to the erase beam is studied by using the coupling wave equation and the band-transport model.The concepts of response strength and the minimum response intensity are introduced and their temperature dependence is investigated.A 2-fold increase in the response strength and 4-fold decrease in minimum response intensity have been experimentally observed in Ce:KNSBN at 633 nm when the crystal temperature is raised from 320 to 370K.These experimental results are in agreement with theoretical analysis and show that the response property can be improved by changing the crystal temperature.
