电线卡作巢脾距离夹

现在很多蜂友不爱用巢脾距离夹，主要是因为没有合适的材料，认为有距离夹使用起来不方便。我认为，还是用距离夹好，至少在检查和运输蜂群时不会压伤蜂王。我是用电线卡作距离夹的，选用高度为8mm的电线卡即可，只要巢框侧条标准就行(宽33mm)，每个巢框用4颗电线卡，钉在侧条两边，上下各两颗，运蜂时将巢脾向一边挤拢，将隔板固定或用塑料卡条紧固即可。

长距离玻璃钢夹砂管水压试验的工程实践

目前关于给水管道水压试验方面的规定是试验长度宜为1km,但对于长距离玻璃钢夹砂管水压试验少有介绍。以新疆哈密鲁能大南湖煤矿输水管道工程为例,介绍了长距离玻璃钢夹砂管水压试验的方案设计、节点工程设计和组织实施的全过程。实践表明,通过合理划分打压段长度,可以解决玻璃钢夹砂管水压试验段落划分短、施工费用高和施工周期长等问题,可为长距离玻璃钢夹砂管的水压试验提供参考。

纵横波测已紧固螺栓轴向应力

本文提出了用纵横波声时测己紧固螺栓轴向应力的一种新方法 ，解决了用超声精确地测已紧固螺栓应力问题，并且利用超声波沿轴向传播的波速同轴向应力以及三阶弹性常数的关系导出了螺栓应力同其材料声速特性、夹紧距离、温度及纵、横波声时的一种新关系，考虑了受应力作用时温度对声速的影响，简化了测量及计算过程。本文还介绍了材料的声速特性实验及测量方法；实验结果表明应力低于 ２５０ＭＰａ；夹紧距离大于 ３０ｍｍ时，应力超声测量的绝对误差小于 １０ＭＰａ。

Study of swelling-shrinkage regularity of montmorillonite crystal and its relation with matric suction

The swell-shrinking mineral of saturated and unsaturated expansive soil has important effect on engineering mechanical behavior. Based on the swelling-shrinkage change regularity of montmorillonite crystal in this paper, the actions between various interlayers of montmorillonite crystal are generally summarized as two kinds of action potentials-shrinkage potential and swelling potential. Moreover, through the experimental research and analysis, the expression formula for variations of the swelling potential and shrinkage potential with interlayer distance is presented, and the regularity of matric suction variations with interlayer distance is also obtained for unsaturated expansive soil. It may provide a new theoretical basis and research path for further research on the swelling-shrinkage mechanism of expansive soil and matric suction potential of unsaturated soil.