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北京市中小学生不同学习阶段心理健康特点的调查 总被引:1,自引:0,他引:1
目的:掌握北京市中小学生在不同学习阶段的心理健康状况和特点,为中小学心理健康教育提供参考和依据。方法:选用俞国良教授编制的《中小学生心理健康量表》为研究工具,在不同的抽样阶段分别采用分层抽样、随机抽样的方法,共获有效问卷4170份。结果:从小学到初中再到高中,北京市中小学生心理健康水平从高到低呈下降趋势。伴随年级因素,小学生、初中生、高中生心理健康状况呈现出不同的特点。结论:中小学生所处的学习阶段和其心理健康状况有密切关系;年级因素和心理健康水平呈现出一定联系,在小学生、初中生、高中生身上分别有各自的特点。 相似文献
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A Comparative Study on the Self Diffusion of N-Octadecane with Crystal and Amorphous Structure by Molecular Dynamics Simulation 下载免费PDF全文
The straight chain n-Mkanes and their mixture, which can be used as phase change materials (PCM) for ther- mal energy storage, have attracted much attention in recent years. We employ the molecular dynamics (MD) simulation to investigate their thermophysical properties, including self diffusion and melting of n-octadecane with crystal and amorphous structures. Our results show that, although the initial and melted structures of n-octadecane with crystal and amorphous are different, the melting behaviors of n-octadeeane judged by the self diffusion behavior are consistent. The MD simulation indicates that both the crystal and amorphous structures are effective for the property investigation of n-octadecane and the simulated conclusion can be used as reference for modeling the alkanes-based PCM system. 相似文献
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对葛洲坝2号船闸的运行资料进行了统计分析,研究了分析了该船闸的故障总体情况,故障发生的原因,时间,部位和故障处理的时间,在此基础上,计算了该船闸各种运行方式的故障率和相应的可靠度。 相似文献
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