基于模糊聚类的国防工程电磁脉冲防护策略探讨

为实现对国防工程内部众多电气设备进行有效合理的防护,达到国防工程对电磁脉冲的整体防护要求;以人防工程为例,分析人防工程内部电气设备的功能特点,确定其评估指标体系,利用模糊聚类的方法,对人防工程内部的电气设备进行模糊聚类,通过对模糊聚类结果的分析,探讨对不同种类的电气设备的防护策略。通过模糊聚类模型而实现的分类防护,可以提高人防工程对电磁脉冲的整体防护效率。采用的方法也可以应用到其他国防工程的电磁脉冲分类防护中去。     

基于贝叶斯网络的航空器看错落错跑道事件研究

目前,航空器看错、落错跑道事件在国际上是一个相当突出的安全问题,这个问题在我国近年也突显出来。导致航空器看错落错跑道的原因十分复杂,且此类事件及易引发严重的后果,造成人、财、物等多方面的损失,本文特对此类问题开展了一系列的研究。为了预防航空器看错、落错跑道事故的发生,查找诱发该类事故的因素,针对航空器看错、落错跑道事故的形成特点,笔者运用贝叶斯网络探讨其各影响因素间的关系和相互作用,该网络强大的逻辑推理能力,克服了不完备样本空间带来的不足,揭示了人、机、环境与管理因素相互作用的内在规律。为改善机场安全管理的科学性、可靠性,进一步降低事故率,提供了可靠的技术支持。     

航空安全信息管理的问题与对策

航空安全信息是民航实施安全风险控制和事故预防的基础,对航空安全水平的提高有重要的作用。笔者总结了民航安全信息的基本构成和来源,及其在安全风险识别、管理决策方面的功用;结合中国民航安全管理状况及行业发展趋势,分析了当前中国民航安全信息管理方面存在的主要问题,指出当前民航安全信息存在着数量不足、质量不高、交流共享困难、分析利用不充分等问题,不利于基于数据驱动的安全管理机制的建立和向规章符合性基础上的绩效管理的转变。针对安全信息管理的这些问题,文章建议民航局通过改善安全信息管理政策、建立航空企业安全信息共享平台、建立国家航空安全信息分析中心、开发安全信息分析利用工具等措施来改善安全信息的收集、分析利用和共享,为提高行业安全管理水平服务。     

民机适航噪声横向衰减特性分析及飞行试验研究

目的 进行民机适航噪声横向衰减建模及特性研究。方法 对民机适航噪声横向衰减工程模型进行分析,建立其主要影响因素的计算模型,基于模型设计等效飞行试验方法,以及试验数据设计横向衰减分析流程,通过某型国产民机噪声飞行试验,对横向衰减特性及模型进行分析。结果 民机适航的横向噪声受声传播效应、地面散射效应和动力装置/机体噪声安装效应等影响较大,声传播效应和地面散射效应分别对高频和低频成分具有显著影响,动力装置/机体噪声安装效应导致的噪声指向性差异也是影响横向衰减的主要因素。对于民机适航噪声评价量,横向衰减模型能够得到与飞行试验结果趋势一致的结果,但工程应用中仍需通过飞行试验进行修正。结论 提出的民机适航噪声横向衰减影响因素的量化计算模型以及等效飞行试验方法,可用于国产民机低噪声设计、噪声适航审定和机场周围噪声污染计算,服务于国产民机设计及适航取证。     

光纤传感器FBG和BOTDR应用于结构监测的若干比较研究

对建筑结构进行健康监测,可以防止和避免灾害的发生。传感器的选择和使用是进行结构监测时首先要考虑的问题。光纤传感器是一种新型的传感器,因种类不同在性能方面也相差较大。FBG(FiberBraggGating,光纤Bragg光栅)和BOTDR(BrillouinOpticalTimeDomainReflectometry,布里渊光时域反射计)是近些年来发展比较快的光纤传感器,本文介绍了这两种光纤传感器,并着重从两者传感的基本原理、传感系统组成、温度补偿研究和性能优劣等方面进行了详细的比较,得出了各自作为结构监测传感器的优缺点,为今后的监测选用提供了依据,使应用两者时能够做到扬长避短。     

Preconcentration of cadmium and copper ions on magnetic core–shell nanoparticles for determination by flame atomic absorption

Magnetic core–shell nanoparticles modified by (3-aminopropyl) trimethoxy silane were prepared and used as adsorbent for the extraction and preconcentration of cadmium and copper ions. The ions were desorbed with nitric acid followed by determination with flame atomic absorption spectrometry. The extraction conditions were investigated systematically. The method was applied for the determination of Cd(II) and Cu(II) ions in different water samples. The accuracy was also evaluated through analysis of certified reference material.     

Exploration of spatial morphometry and socioeconomic variables in modelling urban land use change

The incorporation of land use (LU) data with socioeconomic data is a main issue in modelling. This is as a result of difference in data model and scale. This study proposed and tested the change–pattern approach, which allows the incorporation of these data sets in modelling LU change. Focusing on LU dynamics for a selected part of the Thames Gateway within the City of London, the approach tested two different methods of input selection for the modelling operations. Variables selected from these two methods serve as inputs into several neural networks tested in order to identify the direction of change for each of the LU types within the study area. The result shows that direction of LU change across the study area could be identified when spatial morphology of the area and socioeconomic variables are considered. Some classes of change could be identified fairly accurately using landscape metrics indicating level of fragmentation, extent of LU patches, shape complexity of LU patches in combination with some socioeconomic variables.     

震后民用建筑重建质量监管机制研究

针对震后民用建筑重建质量监管缺失问题,从政府、社会、责任主体三维视角出发,构建了一套促进重建工程质量持续改进的监管机制,并分析该机制具有时空性、多维性、循环性三大特征。另外,为便于社会力量对震后民用建筑重建工程质量进行监督,构建了一套针对非专业人员的工程质量评价指标体系,并利用模糊综合评价法,通过实例验证了该指标体系的有效性。最后,提出了优化该质量监管机制的建议。     

Limiting explosible concentration of hydrogen–oxygen–helium mixtures related to the practical operational case

This paper presents data on the limiting (minimum) concentrations of hydrogen in oxygen, in the presence of added helium, at elevated temperature and pressure related to the practical operational case. A 5 L explosion vessel, an ignition sub-system and a transient pressure measurement sub-system were used. Through a series of experiments carried out using this system, the limiting concentrations of hydrogen in oxygen and helium at different initial pressures and temperatures for the practical operational case were studied, and the influence of ignition energy and initial temperature on the limiting concentration of hydrogen in oxygen and helium was analyzed and discussed. The variation of ignition energy within the studied range is found to have a significant effect on the limiting concentration of hydrogen in oxygen and helium at lower initial temperature. However, when the ignition energy is higher than 32 mJ, the limiting hydrogen concentration remains almost changeless as the initial temperature increases from 21 °C to 90 °C. The limiting explosible concentration of hydrogen–oxygen–helium mixture decreases as the ignition energy increases when the initial temperature is lower. When the initial temperature is higher, the ignition energy has little effect on the limiting hydrogen concentration of hydrogen–oxygen–helium mixtures. When the initial temperature reaches 90 °C, the limiting hydrogen concentration remains almost changeless with an increase in ignition energy. The limiting explosible concentration of hydrogen in the mixtures, at the initial temperature of 21 °C and the ignition energy of 0.5 mJ, is 8.5% and that of oxygen is 11.25%.