杂散电流腐蚀防护与测试

首先介绍了杂散电流的基本概念、特点及分类,接着分析了目前国内外测试杂散电流的两种主要检测技术的工作原理,并且总结了杂散电流测试仪在实际工程中的应用,介绍了杂散电流测试仪的构成和功能特点,分析比较了国内外杂散电流测试仪,最后介绍了各种防护措施的工作原理,同时总结比较了各种措施的优缺点.通过对杂散电流的研究分析,可以为找出主要问题,探索解决的方案,并为降低杂散电流的影响提供了有力参考.     

去耦合器排流技术在管道交流干扰减缓中的应用

固态去耦合器已经在国内的管道设计中得到了应用,做为交流减缓技术,固态去耦合器还可有效消除交流感应电压而不引入杂散电流或者流失阴极保护电流.文中介绍了去耦合器的一些基本特性与设计理念.测试并评价了去耦合器技术在兰郑长管道的具体应用情况.现场应用表明:去耦合器做为一种交流排流技术,可在管道的交流干扰减缓中大量推广应用.     

高速公路沼泽湿地路基施工中冲击碾压技术的应用

在高速公路建设中,路基工程的填筑质量越来越受到重视.在青海省共和至玉树高速路基施工过程中,广泛采用了冲击碾压对沼泽湿地路基进行压实补强.本文在阐述冲击碾压压实机理的基础上,结合共和至玉树高速公路施工,介绍了冲击压实工艺以及在高速公路特殊路基基底处理的应用.     

SCADA系统在埋地管道杂散电流监测中的应用方案

根据长输埋地管道分布地域广、所处的环境相对复杂等特点,提出了杂散电流监测方案,将基于无线通讯方式的SCADA系统应用到长输埋地管道杂散电流监测中,实现远程数据采集和监控,能及时发现杂散电流对埋地管道干扰的异常情况.对监测方案的介绍主要包括系统总体结构,硬件和软件构成等方面.     

冲击式压路机在路基施工中的应用

介绍了冲击式压路机在龙长高速公路A8合同段路基施工中,对于加强补压、减少工后沉降量的应用.     

基于TMS320VC5509A的埋地长输管线杂散电流检测仪

针对目前市场上埋地长输气管线杂散电流测试仪普遍采用传统的英文字符显示屏作为人机交互界面,以及仪器操作显示的信息量大的问题,设计了全中文界面显示的杂散电流测试仪.设计中,采用TMS320VC5509A作为主控芯片,并选用320×240点阵字符显示屏,能方便直观地完成杂散电流的测试、实时波形显示、参数设定,提高了维护效率,降低了维护成本.     

高速铁路动车组不断电过分相技术研究

文章介绍了一种用于高速铁路动车组不断电过分相技术。该技术基于先进的电力电子技术,采用大功率晶闸管阀组作为开关装置,开关过程对动车组及接触网无电压电流冲击,动车组在过电分相时不失电,避免了现有车载断电过分相方式中存在的退级降速-重合闸增流加速过程问题,提高了高速铁路运行效率。     

电流环法测试管中电流技术应用

由于实际管道中阴极保护电流较小以及现场环境干扰严重,现有的方法难以测得真实的管中电流。文中结合现场案例,通过与电位差法作对比,介绍了电流环法在测量埋地管道管中电流方面的应用。结果表明：电流环法可以测量管道中电流的大小及方向;电流环法与电位差法测得的电流数值基本相同,但电流环法的测量值更稳定;由于地磁场对电流环的影响范围在±100 mA之内,当管中电流小于100 mA时,测试数值正负跳动,无法取值,也不能判断电流方向,电流环法不适用。     

冲击碾压技术在高速公路施工中的应用

高速公路施工中,冲击碾压技术是影响高速公路整体施工质量的关键。文章介绍了冲击碾压技术的工作原理及应用特点,探讨了冲击碾压技术在高速公路施工中的应用方法与注意事项。     

冲击碾压技术在高速公路路基施工中的运用

文章首先阐述了冲击碾压技术的基本原理,通过工程案例重点分析了冲击碾压技术在高速公路路基施工中的应用,再结合作者实际施工经验,详细论述了在进行路基冲击碾压施工过程中的质量控制,具有一定的参考价值.     

防雷器远程自动无线监控系统在高速公路机电系统中的应用

文章介绍了防雷器远程自动无线监控系统的系统构成及工作模式,阐述了该系统的技术优点、使用局限性及成本控制措施,并结合广西高速公路工程应用实例,提出了该系统在高速公路机电系统建设中的应用方式与前景。     

GPS在水文测量中的应用

文章结合GPS在水文测量中的应用,探讨在仪器设备先进的情况下,如何更有效地提高水下地形测量的精度和工作效率,介绍流态观测和流量测量定位的新方法,总结GPS在水文测量中值得注意的几个问题。     

GPS-RTK在水下地形测量中的应用

RTK(Real Ti me Kinematic)定位技术是GPS定位技术的一项飞跃,文章通过工程实例,介绍了GPS-RTK在水下测量中的应用,对其作业流程和关键技术问题进行了分析,得出了一些有益的结论。     

Using ordered attitudinal indicators in a latent variable choice model: a study of the impact of security on rail travel behaviour

There is growing interest in the use of models that recognise the role of individuals’ attitudes and perceptions in choice behaviour. Rather than relying on simple linear approaches or a potentially bias-inducing deterministic approach based on incorporating stated attitudinal indicators directly in the choice model, researchers have recently recognised the latent nature of attitudes. The uptake of such latent attitude models in applied work has however been slow, while a number of overly simplistic assumptions are also commonly made. In this article, we present an application of jointly estimated attitudinal and choice models to a real-world transport study, looking at the role of latent attitudes in a rail travel context. Our results show the impact that concern with privacy, liberty and security, and distrust of business, technology and authority have on the desire for rail travel in the face of increased security measures, as well as for universal security checks. Alongside demonstrating the applicability of the model in applied work, we also address a number of theoretical issues. We first show the equivalence of two different normalisations discussed in the literature. Unlike many other latent attitude studies, we explicitly recognise the repeated choice nature of the data. Finally, the main methodological contribution comes in replacing the typically used continuous model for attitudinal response by an ordered logit structure which more correctly accounts for the ordinal nature of the indicators.     

Service network design with asset management: Formulations and comparative analyses

In this paper, we address the service network design with asset management problem, which integrates asset management considerations into service network design models for consolidation-based freight carriers. We propose model formulations based on arc variables for both flow and design, as well as formulations with path flow variables and new cycle design variables. Problem instances reflecting actual planning problems are used in the computational study to analyze the strengths and weaknesses of the various model formulations and the impact of asset management considerations on the transportation plan and the computational effort. Experimental results indicate that formulations based on cycle variables outperform traditional arc-based formulations, and that considering asset management issues may significantly impact the outcome of service planning models.     

Design and shared use of a terminal departure lounge for new large aircraft operations

New Large Aircraft (NLA) are new aircraft developments larger than any existing aircraft. The NLA's higher seat capacity will significantly impact passenger terminal design and operations. This paper focuses on the issues regarding the departure lounge. Deterministic queuing theory is used to determine the size and seating configuration of the lounge, as well as to decide whether a second level should be built to accommodate the increase in the number of passengers. The paper also discusses the use of the satellite section of a pier‐satellite terminal as a single lounge for the NLA. Spreadsheets are used to implement the analyses.     

药芯焊丝自保护焊在长输管道施工中的应用

介绍了药芯焊丝自保护下向焊技术.通过反复试验和在工程中的实际应用,分析不同工艺参数及操作手法对焊接质量的影响,制定了合理的焊接工艺匹配参数,并确定了恰当的焊接操作手法.同时,也简要介绍了焊前准备、组对、层间清渣、设备计量及工序控制等对焊接质量的影响.根据该技术在长输管道工程中的应用,指明药芯焊丝自保护焊技术的发展与完善将是我国大口径长输管道焊接技术的发展方向.     

Evidence of land use impacts of rapid transit systems

This paper draws from the findings of published empirical studies and observations of the impacts of rapid transit systems on urban development. Analysis is based on comparisons of impact findings by different researchers and for different cities. An initial set of key issues is proposed, against which available information is arrayed and compared. It is concluded that rapid transit can have substantial growth-focusing impacts, but only if other supporting factors are present.     

Measuring supply chain efficiency based on a hybrid approach

Supply chain management has a tremendous impact on the success of a company. One of the critical issues for gaining competitive advantages for companies is improving supply chain performance. Most studies about the application of Data Envelopment Analysis (DEA) Supply chain models do not identify the benchmarking units for inefficient supply chains. On the other, measuring the short run and long run of the supply chain efficiency is another challenge for decision makers in supply chain management. Hence, we propose a methodology of DEA for measuring of the supply chain. We integrated two approaches as special cases of the hybrid model and compare the short and long run strategies of supply chain and can be identified benchmarking.     

公路隧道环境影响评价中存在的问题与对策建议

公路隧道环境影响评价在预防和减缓隧道建设、运营对生态环境的影响上起着重要的作用.文章在对公路隧道环评实践过程中存在的现行法规难以完全满足环评需要、环评介入时间滞后以及其他一些环评技术问题进行分析讨论的基础上.提出了制定隧道环评专门法规、加强隧道环评监管和提高隧道环评人员素质的对策建议.