粉细砂层中穿越铁路顶管施工技术应用

针对粉细砂地质条件下穿越高速铁路,管道覆土浅的一类顶管施工技术展开研究分析,并通过广州市西江引水工程———穿越京广铁路顶管工程的施工运用实践,总结了一套针对该类型顶管工程的行之有效的顶管施工技术和宝贵的顶管施工经验。     

建陶坯体干燥过程中传热性能的实验研究

为研究建陶坯体干燥过程中的传热性能,使用导热系数测试仪对不同排水率下的建陶坯体的导热系数进行了实验研究;为降低接触热阻的影响,在坯体与铜板间涂以导热胶,最后对实验误差进行了分析。实验结果表明,坯体导热系数随温度线性增加,随着排水率的增加而减小。     

一种基于信号处理的异步干扰消除方法

分析了异步干扰的成因及处理措施,并提出一种基于信号处理的异步干扰剔除方法。该算法利用异步干扰的奇异性,对输入信号进行脉冲对消、CFAR处理。根据信号既往信息,建立距离杂波图。根据距离杂波图进行门限检测。对所有过门限信号采用逻辑法将奇异值所在脉冲及距离单元定位出来。对检测出来的对奇异值,使用相邻信号进行插值替换,既保留了信号的真实成份,又消除了异步干扰。该算法处理延时小。该算法已在FPGA上实现,并在某雷达中得到了很好的应用,具有很强的工程实用性。     

基于可见-近红外光谱技术的润滑油酸值无损检测方法研究

研究了基于可见-近红外光谱技术的润滑油酸值无损检测方法.获得了润滑油在475～975 nm范围内的可见-近红外光谱.采用最小二乘支持向量机(LS-SVM)建立可见-近红外光谱检测模型,并通过将无信息变量消除算法(UVE)与连续投影算法(SPA)相结合进行光谱有效波长选取.通过UVE-SPA法进行变量选择计算,最终将原始...     

复杂岩层大断面硐室群围岩破坏机理及控制

针对复杂岩层巷道交叉点高应力集中区四周硐室群开挖围岩稳定性控制和支护技术等难题,通过对现场取样测试硐室群围岩物理力学参数、黏土矿物成分和松动圈大小,分析了赵庄煤矿三盘区带式输送机头硐室群及周边巷道围岩变形破坏特征和机理,表明硐室帮部煤柱和底板围岩是加固支护重点。利用FLAC3D数值模拟软件分析了硐室群开挖对硐室群及周边巷道围岩应力分布和塑性区分布范围的影响。基于理论分析和数值模拟提出了硐室及周边20 m范围内巷道围岩"强柱固底"的加固支护方案。现场工业试验表明,加固支护后,硐室群及周边巷道围岩变形得到了有效控制,围岩内部裂隙基本被浆液填充,60 d内围岩顶底板和两帮最大移近量分别为30 mm和50 mm,达到了理想的加固支护效果。     

气压平衡顶管法及其在油气管道穿越软土地段的应用

随着社会的日益进步和经济的快速发展,顶管穿越技术在油气管道穿越工程中的应用越来越广泛。然而,在实际应用过程中应根据不同地层情况,采用不同的顶管穿越方式。介绍了气压平衡顶管法的原理、特点及分类情况。并结合中山—广州天然气管道工程实例,总结了气压平衡法在油气管道穿越软土地段中的施工技术。     

基于产品供电接口时序逻辑的设备检测装置

目前传统的测试设备自检单元仅对各路激励信号和采集通道进行检查,而无法检测到工作时序逻辑,一旦测试设备时序出现异常将对产品测试安全性造成影响。为此,文中提出了一种基于时序逻辑的测试设备检测装置设计方法,介绍了检测装置的软硬件开发以及工作流程和主要功能,实际应用结果分析表明,该检测装置大幅提高了对测试设备的检测深度,在设备早期故障剔除和产品测试安全性方面均有较大的改进。     

Illegal road crossing behavior of pedestrians at overpass locations: Factors affecting gap acceptance,crossing times and overpass use

The aim of designing overpasses is to provide safe road crossings for pedestrians by helping them to avoid conflicts with motor vehicles. However, the number of pedestrians who do not use overpasses to cross the road is very high. An observational survey of illegal road crossings was conducted at four overpass locations in Izmir, Turkey to determine the crossing time, crossing speed of the pedestrians and their distance and time gap perception for safe road-crossing within 25 m of the overpasses in both directions. Crossing time is the time needed for a pedestrian to cross a particular road. Time gap is strongly related with safety margin. If a pedestrian chooses a larger time gap, then the arrival time of the oncoming vehicle to the crossing point of the pedestrian increases thus, the possibility of a collision decreases. Each overpass was observed on weekdays during peak afternoon (12.30–13.30) and evening hours (17.00–18.00). At all overpass locations 454 illegal crossings were observed. ANOVA results revealed that age had a significant effect both on safety margin and crossing time. During the observations a survey was conducted among pedestrians who completed their crossings either using the overpass or at street level within 25 m of the overpass (n = 231). Factors affecting the crossing choice of pedestrians were specified in the surveys. The major part of the respondents (71.7%) indicated that time saving was the main reason for crossing at street level. Pedestrians’ crossing speeds were extracted from the video recordings to observe the effect of speed limit on pedestrian behavior. As a result, at locations where the speed limit was 70 km/h, pedestrians’ average crossing speed was found to be 1.60 m/s and 1.73 m/s while at locations where the speed limit was 50 km/h, pedestrians’ average crossing speed was found to be 1.04 m/s and 0.97 m/s. This shows that pedestrians feel safer while crossing when the vehicle speed is low.     

天文光电图像序列空间目标虚警消除技术

空间目标虚警主要来自恒星目标、恒星目标拖尾、空间目标的拖尾、背景图像及噪声,其虚警消除效果直接影响了整个天文光电观测系统的检测概率和虚警概率.在深入分析空间目标虚警来源的基础上,根据不同类型的虚警在图像中的不同特点,提出了相应的消除虚警的方法:1)利用目标的基本特征消除虚警;2)基于恒星目标拖尾和空间目标拖尾定位的方法...