严寒地区高速铁路混凝土基床聚氨酯保温特性试验研究

基于严寒区京沈客专朝阳试验段路基基床的温度监测资料分析,研究不同厚度聚氨酯保温板对高速铁路路基混凝土基床温度变化特性影响.测试结果表明:①铺设聚氨酯保温板能够有效阻断严寒区环境与路基基床间的热量传递,保温效果与板厚相关;②地温大多数时间呈阳高阴低现象,同时阴、阳坡路基温差波动幅度随埋深逐渐减小;③基床表层阴、阳面各测点的温度变化起始时间一致,而阴面的冻结时间比阳面晚一个月.由此表明,保温板能够有效降低环境与混凝土道床之间的热交换,但是对路基阴、阳坡的影响存在差异.建议在严寒地区高速铁路路基阳、阴坡可以采取不同厚度的聚氨酯保温板,减小阴阳坡地温差异,保持季冻土路基温度变化稳定.     

Forecasting unknown-unknowns by boosting the risk radar within the risk intelligent organisation

This theoretical perspective paper interprets (un)known-(un)known risk quadrants as being formed from both abstract and concrete risk knowledge. It shows that these quadrants are useful for categorising risk forecasting challenges against the levels of abstract and concrete risk knowledge that are typically available, as well as for measuring perceived levels of abstract and concrete risk knowledge available for forecasting in psychometric research. Drawing on cybersecurity risk examples, a case is made for refocusing risk management forecasting efforts towards changing unknown-unknowns into known-knowns. We propose that this be achieved by developing the ‘boosted risk radar’ as organisational practice, where suitably ‘risk intelligent’ managers gather ‘risk intelligence information’, such that the ‘risk intelligent organisation’ can purposefully co-develop both abstract and concrete risk forecasting knowledge. We also illustrate what this can entail in simple practical terms within organisations.     

《难经》压力波参数初探

根据压力波理论，分析了《难经》脉状的参数，演绎了主要参数的特征曲线，这对推进中医切诊医术的现代化具有现实意义。     

雷达接收机数据采集平台及其FFT实现

介绍了小型化、通用化和实时信号处理要求下，雷达接收机的通用数据采集处理硬件平台。采用Xilinx公司最新平台级FPGA产品Spartan-3系列芯片构建平台，并实现其中的FFT于模块。试验表明，处理精度和速度都满足要求，为该方案的可行性和后续模块的实现提供了依据。     

“民主化”改革与地区经济表现

依据Polity IV数据库数据,考量20世纪90年代以来“第三波民主化浪潮”中,发展中国家朝着西方价值标准“民主”的重大转变对其经济表现的影响。结果显示,没有证据支持“民主化”改革促进了经济增长;相反,“民主化”改革引致国家治理能力下降,阻碍了经济发展。异质性分析表明,“民主化”改革对经济发展的负效应主要出现在撒哈拉以南非洲地区,且激进的“民主化”改革和被殖民国家的“民主化”改革对经济发展的负面影响更大。鉴于此,西方价值标准的民主既非一国经济发展的充分条件,也非一国经济发展的必要条件,一国选择何种国家治理模式与政治体制应考虑自身的历史、文化、发展阶段等实际国情,而不是盲目推行西式“民主化”。     

低应变反射波法在PHC管桩完整性检测中的应用分析

根据低应变反射波法检测高强度预应力混凝土管桩(PHC)桩身完整性的原理,通过具体工程实例对低应变反射波检测PHC管桩有关问题进行了分析探讨。     

多级斜坡路基软弱地基变形机理和稳定性数值分析

山区公路路基往往是在斜坡上填筑的,这种填筑形式更易于发生变形破坏,故本文以某斜坡路基为研究对象,研究斜坡路基地基变形机理,并用强度折减法分析该斜坡路基的稳定性。结果表明:①地基形变的总体趋势以沉降变形为主,随填筑高度的增加,水平位移逐渐趋于均匀,并表现为侧向外鼓,沉降最大值集中在与填筑体中心相交的区域。②路基中心的最终沉降位移相较于坡脚的2倍;路基整体有向斜坡下滑移的趋势;短坡脚的水平位移发展最快。③斜坡路基随填筑高度的增加,从深层滑动发展为浅层滑动,滑体集中于长坡脚。④随填筑高度的增加,安全系数逐渐降低。     

探地雷达在公路改扩建工程检测中的应用

公路改扩建工程在广东省正处于快速发展时期,如何准确得到路面病害情况,是旧路处治方案制定面临的主要问题.依托开阳高速改扩建工程,采用三维探地雷达对旧路进行病害检测,得到道路表面及内部的病害分布情况,并分别与人工徒步调查路况及开挖后内部实际情况进行比对.结果表明:当三维探地雷达检测采样间距设置为2.0 cm、驻波时间设置为0.6 ms、时窗设置为85 ns时,可达到较好的检测精准度;三维探地雷达可实现对路面结构内部不同深度位置的裂缝病害进行探测,精确识别3 mm宽裂缝,并了解裂缝的发展方向及性质.     

较差质量数据下的返回弹道计算及对落点影响的分析

针对某老式卫星返回时雷达跟踪数据曾发生的测量异常及质量较差等情况，为解决此类数据在返回弹道及落点计算中出现的实际困难以及给出应对措施，基于工程实际情况给出了三种不同建模类型下的弹道计算方法——当前统计解耦扩展卡尔曼滤波（EKF）、动力学建模无迹卡尔曼滤波（UKF）、多项式滑窗最小二乘估计算法，并应用该次质量较差的实际观测数据进行了算法应用效果分析与落点计算情况对比，对计算中的经验及教训进行了总结。研究结果表明，所给出的三种算法在面对较差质量数据时性能差异较大，在工程实际应用中可考虑将多种算法互为参考。研究结果及其经验教训对卫星返回弹道及落点的实时估计的工程实施有一定的参考价值。     

Effects of non-aeronautical activities at airports on the public transport access system: A case study of Zurich Airport

Many planning authorities and airports study measures to increase public transport use for airport ground access and egress. At the same time, an increase in real estate development at and around airports is occurring, both due to airports seeking new revenue possibilities and other developers attempting to profit from high value locations. This paper considers non-aeronautical activities at large airports, largely commercial centres and transit hubs, as land uses that have the potential to improve the situation for operating public transport services. In order to assess potential benefits and disadvantages, four research questions are considered: (1) Can the additional travel volume reach levels at which it has a significant impact? (2) To what extent do non-aeronautical activities influence the public transport access system? (3) Is the resulting demand distribution better or worse regarding peaking behaviour? (4) Is there a potential for the resulting overall demand to bring about capacity shortages?A case study is conducted at the airport of Zurich, Switzerland, which finds that non-aeronautical activities in the direct airport vicinity have led to a situation where the operation of public transport services is much more viable due to overall higher passenger numbers and a more even distribution throughout the day. It is concluded that locating non-aeronautical activities at airports can, in addition to providing commercial benefits to developers, lead to a situation where improved public transport services become feasible.