稳定元素Sr在土柱中的迁移

文章涉及稳定元素Sr在现场进行的水平土柱示踪实验和在实验室进行的垂直土柱模拟实验的实验方法和实验结果。实验结果表明:黄土对Sr有较强的吸附能力;实验室垂直土柱模拟实验的轴心纵向延迟系数略小于外侧纵向的数值;含水层水平土柱中Sr的延迟系数略小于实验室垂直土柱模拟实验的结果,这可能是由于土柱中的水流速度和土壤的密度不同而造成的。

面对面和计算机群体决策运用排序法上的比较

通过人员选拔的实验室模拟实验,比较面对面的和以计算机为中介的决策群体在信息是否完全分享及是否采用排序法决策条件下对于决策效标的影响。结果表明:(1)决策前的信息分享通过决策前偏好的人数构成影响了最终的决策准确率。(2)排序法在面对面交流时只在信息非分享的情况下才显著增加了关键信息交流;排序法在计算机交流和信息完全分享下显著增加了关键信息交流。弥补了Hollingshead的研究不足之处。排序法不损害成员对于讨论的满意感。(3)计算机交流更关注文本信息,有更多争论、自我观点阐述和申诉。在关键信息交流上与面对面交流没有差异。(4)在决策准确性上,不同的交流方式没有差异。

高炉喷煤支管用声纳喷管的现场实验

1 实验准备经过实验室模拟实验之后,在宝钢设计院的组织下。宝钢设计院工艺一室、东北大学项目组和宝钢炼铁厂3号高炉喷煤组于1998年8月25～27日在3号高炉上实施了声纳喷管应用的现场实验,以进一步实地考察声纳喷管的应用效果和前景。

Ultrasonic vibrations and coal permeability: Laboratory experimental investigations and numerical simulations

Ultrasonic vibrations in coal lead to cavitation bubble oscillation, growth, shrinkage, and collapse, and the strong vibration of cavitation bubbles not only makes coal pores break and cracks propagate, but plays an important role in enhancing the permeability of coal. In this paper, the influence of ultrasonic cavitation on coal and the effects of the sonic waves on crack generation, propagation, connection, as well as the effect of cracks on the coal permeability, are studied. The experimental results show that cracks in coal are generated even connected rapidly after ultrasonic cavitation. Under the effect of ultrasonic cavitation,the permeability increases between 30% and 60%, and the number of cracks in coal also significantly increased. Numerical experiments show that the effective sound pressure is beneficial to fracture propagation and connection, and it is closely related to the permeability. Moreover, the numerical simulations and physical experiments provide a guide for the coal permeability improvement.

实践性教学方法特点浅议

实践性教学具有开放性、灵活性.多样性等特点、它不仅对教学过程中的主体、客体(教师和学生)具有开放性.而且教学的内容、范围、方式和方法也具有开放性.灵活性、多样性.因此.就现实而言,要把握住实践性教学的这些特征.努力改进教学方法.才能使实践性教学取得良好的效果.