准高速东风型列车风速度场特性初探

本文利用三维超声风速温度仪及数字三杯式风速仪，测量了列车风的速度分布，初步探讨了速度场的诸多特性－－非定常特性，沿侧向分布特性，与列车速度、自然风风、风速关系等。     

酸雾灵对酸洗槽酸雾抑制作用的效果评价

对我市某厂使用酸雾灵控制酸洗槽酸雾的效果进行了评价。结果表明，酸洗时未加酸雾灵车间内硫酸雾浓度范围为１．１ｍｇ／ｍ３～９９２ｍｇ／ｍ３，平均浓度为１６３．９ｍｇ／ｍ３，样品超标率为９５．８％。使用酸雾灵后车间内硫酸浓度范围为０．２４ｍｇ／ｍ３～１０．６ｍｇ／ｍ３，平均浓度为２．４９ｍｇ／ｍ３，样品超标率为３３．３％。表明酸雾灵能比较有效地控制硫酸的蒸发。     

BOT融资关键因素分析--从国内外BOT项目的经验教训说起

本文总结了国内外BOT项目融资成功的经验和失败的教训,分析了保证项目融资成功的8个关键因素,旨在为我国实施BOT项目提供可借鉴的经验。     

680Q汽油机曲轴橡胶扭振减振器设计与试验研究

目前,小型高速发动机一般都采用橡胶式扭振减振器.这种减振器是利用惯性块的惯量和橡胶的弹性来改变原系统的扭振特性,并依靠橡胶的内摩擦阻尼吸收部分振动能量,使曲轴扭振得以减弱.橡胶式扭振减振器与上海牌轿车680Q型汽油机原装用的摩擦片式减振器相比,具有结构简单、制造容易、重量轻、成本低、工作可靠、维护方便等优点.因此,上海牌轿     

捷运工程之联络信道采压气工法辅助施工案例探讨

高雄捷运橘线CO1区段标统包工程潜盾隧道分别穿越高雄港第三船渠及仁爱河,且本工程4座联络信道中有3座位于水际,开挖地层又属高地下水位之疏松粉土质砂层,施工风险较高.本工程原有2座联络信道已依设计分析结果采JSG高压喷射搅拌工法进行地质改良并采压气辅助施工顺利完成,后续2座原规划仅采用隧挖方式施工,惟在施工前恰巧邻标联络通道内集水井施工发生重大意外事故,且从该地区之地层特性等因素分析,为进一步降低施工风险,仍续采压气工法辅助施工.本文旨在说明本工程采压气工法辅助施工之设计与施工问题点与解决对策,以提供类似工程之参考.     

Model test for dynamic construction mechanical effect of large-span loess tunnel

It has been a focus of debate for a large time on construction methods for large-span loess tunnel. Reasonable construction method has much effect on stability of tunnel and construction schedule. Deformation and failure of surrounding rock are quite complex. Associating with the large-span loess tunnel of Zhengzhou—Xi’an high-speed passenger rail line in China, large scale model test with geometric proportion 1:20 is applied to study on dynamic mechanical behavior of various construction methods. They include full-face excavation with support and no support, and benching method with support. It is found that pre-deformation and stress accumulation take place ahead of working face. The effects of three construction methods are further studied, particularly in terms of tunnel displacement and stress changes. It is revealed that benching method transfers load to an unexcavated area, limits horizontal deformation, reduces stress concentration effectively, lengthens the distance between location of peak for stress concentration and working face, and consequently increases stability. The model test results not only supply theoretical foundation for determination of reasonable construction method, but also can act as reference for similar tunnel and underground engineering construction.