水平定向钻在公路隧道工程中的应用及分析

本文结合工程实例,通过水平定向钻技术在中国交建新疆乌尉公路PPP项目6标段,天山胜利隧道出口段超前水平地质定向钻工程中的成功应用,总结了在岩层高落差、小曲率半径钻进施工中遇到的各项干扰及导向难度等问题,积累了穿越公路隧道工程的施工经验,同时也为以后类似工程提供借鉴经验。

A rapid on-site calibration method for measuring dynamic envelope curve of high-speed trains

Dynamic envelope curve is a significant parameter to assess the running safety of high-speed trains.Up to now the method based on binocular stereo vision is the only way available to measure the dynamic envelope curve of a train,the speed of which is over200km/h.Nevertheless the method has two limitations,one is large field-〇f-view(FO V),the other is calibration time.Hence portable calibration equipment,easy-t〇-build target and rapid calibration algorithm are required to complete the calibration.In this paper,a new rapid on-site calibration method with large FOV based on binocular stereo vision is proposed.To address these issues,a light target has been designed,the rail coordinate system(RCS)is represented by40fixed retroreflective points on the target,and they are utilized to calibrate the parameters of two cameras.In addition,two cameras merely capture a single image of the target simultaneously,and the intrinsic and extrinsic parameters of the cameras can be calculated rapidly.To testify the proposed method,the experiments have been conducted and the results reveal that the accuracy can reach+1mm,which can meet the measurement requirement.

某医院万级洁净手术室尘埃粒子动态监测及影响因素相关性分析

目的 了解洁净手术室万级手术间尘埃粒子动态变化规律及影响因素,为保障洁净手术室的空气质量,制订手术部位感染防控措施提供理论依据。方法 对某三甲综合医院洁净手术室万级手术间尘埃粒子进行动态监测,同时收集温湿度、压差、开门次数、室内人数等可能影响尘埃粒子计数的影响因素数据进行分析,监测时段涵盖术前准备、手术进行整个过程。结果 术前准备时尘埃粒子因铺单、穿手术衣等操作而迅速升高,直径≥0.5μm的尘埃粒子数(PM_(0.5))在切皮时达最高,直径≥5.0μm的尘埃粒子数(PM_(5.0))在铺单时达最高,随着手术的进行尘埃粒子逐渐减少,术中部分时段可达静态标准;尘埃粒子数与温度、湿度、压差、铺单穿手术衣操作、开门频次、室内人员活动相关。结论 除控制温度、湿度、压差等基本参数外,在手术切皮前强制设定3~5 min的静默期、将切皮前尘埃粒子监测列入日常监测、在手术准备及手术过程中严格限制不必要的开门次数和室内人员活动可有效保证手术室的空气质量。