THEORETICAL ANALYSIS OF USING AIRFLOW TO PURGE RESIDUAL WATER IN AN INCLINED PIPE

A refined theoretical analysis for using the spiral airflow and axial airflow to purge residual water in an inclined pipe was presented. The computations reveal that, in most cases, the spiral flow can purge the residual water in the inclined pipe indeed while the axial flow may induce back flow of the water, just as predicted in the experiments presented by Horii and Zhao et al. In addition, the effects of various initial conditions on water purging were studied in detail for both the spiral and axial flow cases.

1～3岁幼儿面孔表情认知发展特征研究

目的探讨1～3岁幼儿对5种面孔表情的认知反应发展特征。方法选择2006年11月至2008年11月,在中山大学附属第三医院和佛山市妇幼保健院常规保健的1～3岁幼儿180例作为观察对象,让幼儿观看电脑屏幕上呈现的5种标准面孔表情图,记录、编码和分析幼儿对面孔表情图的视觉注意、自身情绪和行为反应。结果1～2岁组幼儿对5种不同表情图的初次注视时间比较,差异无显著意义(P>0.05),2～3岁组幼儿对5种不同表情图的初次注视时间比较,差异无显著意义(P<0.01)。幼儿对5种表情图的回看次数和组别效应均不显著。1～1.5岁组幼儿对5种表情的初次注视时间和总注视时间短于其他两组(P<0.01)。各组幼儿对5种不同表情图的积极和消极情绪得分比较,差异有显著意义(P<0.05)。各组幼儿回看母亲、手指指向行为发生率比较,差异无显著意义(P>0.05),模仿表情行为发生率和语言表达能力比较,差异有显著意义(P<0.001)。结论1岁以后,幼儿基本能感知和识别不同情绪意义的面孔表情,并开始逐渐对表情进行分类和概念化,但很粗浅。