descending urography

Research on application of downward ventilation to coal mining face in horizontal seam with coal outburst in potential;

近水平突出煤层回采工作面下行通风应用研究

Field experiments using downward ventilation were studied and the gas emission and distribution laws at the goaf working face were discussed.

结果表明,在采用下行通风后,采空区绝对瓦斯涌出量为上行风时的80%,工作面φ(CH4)下降了75%,瓦斯不再超限。

In order to investigate the solid concentrations in the fully developed region of the circulating fluidized bed(CFB)downers,the actual solid concentration was measured by an optical solid concentration probe in a 9.

在较宽的操作条件范围内采用光纤颗粒浓度探头测定了下行管(φ100mm×9。

This paper discussed methane emission,the reasons for methane reduction in up corner,problems should be considered in the condition of change from normal ventilation into downriver ventilation.

对下行通风时瓦斯涌出及下隅角瓦斯减少的原因进行论证,对上行风改为下行风应注意的问题进行了论证。

After finishing the face mining,the down dismantling method is applied for face move.

工作面回采结束后,采用下行拆除的方法进行搬面。

In order to find more effective control measurements for declensional ventilation mine fire,the catastrophe potential function of airflow reversal in a declensional ventilated mine fire was deduced by using catastrophe theory,which indicates the airflow reversing process has discontinuous characteristics.

为了寻求下行风流火灾的有效控制途径,应用突变理论推导了下行通风主干风路风流逆转的突变势函数,揭示出其逆转过程具有突变特征,分析了下行风流逆转具有的突跳、分叉、不可达、滞后、多模态等多种非线性特征,实验验证了下行风流逆转的突变过程。

Based on the analysis of the mechanism on the tubing-rod wearing in detail, a novel design of low friction sucker pump has been developed recently which can reduce the rods' friction in down stroke effecti.

为降低杆柱下行阻力,减缓杆管偏磨,延长检泵周期,开发并应用了低磨阻泵。