吸收冲击载荷的消震带

<正> 大家知道,建筑工人用的保险带、保险网,运载工具的安全带和登山运动员用的保险系统里都配有能吸收冲击载荷的消震带,以使冲击作用减小到人们经受得了的最高的     

非对称单筒双井技术在文昌13-2油田的应用

南海西部文昌13-2油田目前共有开发井12口,油田已经没有空井槽,为充分开发油田,提高采收率,确定在文昌13-2油田A平台内挂4个?762 mm井槽,采用单筒双井技术,利用平台125t修井机,在?762 mm隔水管内下入?339.7 mm套管和?244.5mm套管,并利用?339.7 mm套管进行单筒双井的固井作业,实现了在同一井槽内完成2口不同井身结构的水平井钻完井作业。以同一槽口A16h井和A17h井为例,介绍了非对称单筒双井钻井程序、工艺特点以及钻井期间注意事项。单筒双井技术在文昌13-2平台成功的应用,充分地利用了井口平台的空间,减少了工程造价,降低了开发成本,摸索出了一套成功经验。     

低温硅双极晶体管基区优化设计

常规双极晶体管在７７Ｋ下电流增益和频率性能都严重退化。本文首先分析了低温双极晶体管基区Ｇｕｍｍｅｌ数，基区方块电阻，渡越时间和穿通电压等参数与温度及基区掺杂的关系，然后讨论了低温双极器件基区的优化设计问题。     

蚕庄金矿倾斜采场的地压研究

本文使用工程地质、室内试验及数值分析的方法对蚕庄金矿的倾斜矿房的地压活动规律进行了研究，得出了一些有价值的结论。     

评我国矿用防爆产品发展现状

分析了1988—1989年间国产的防爆产品中有一定技术难度的新产品较少,应淘汰的老产品被大量扩点生产,反映了科技规划和管理的混乱。为使我国矿用防爆产品能健康发展,提出了若干设想。     

MS方法的一个新证明及其结构优化算法

本文给出Ｍｉｌｎｅ－Ｓｉｍｐｓｏｎ（ＭＳ）预测─校正法新的导出方法，并以结构优化思想设计出通用性和可靠性较强的算法。     

Effect of fiber types on relevant properties of porous asphalt

The research was conducted to evaluate the effects of cellulose and polyester fibers on the properties of porous asphalt mixes, using the tests of draindown, abrasion, volumetric properties, rutting, and moisture damage. Images of scanning electron microscopy and X-ray computerized tomography were adopted to identify the microstructure of the fiber and inner stone skeleton of porous asphalt. The influence of rutting parameter （G＊/sin δ） of asphalt modified by different fibers on the rutting resistance of the mixes was investigated. Based upon MOHR-COULOMB theory, the cohesion and the angle of internal friction of the mixes were derived from both indirect tension and unconfined compression strength. The experimental results indicate that fibers mainly stabilize asphalt binder and thicken asphalt film around aggregates. Furthermore, they result in the improved mechanical strength of porous asphalt mixes at high temperature slightly. From comparison analysis, cellulose fibers appear to perform better than polyester fibers in porous asphalt mixes.