电网安全风险管理

随着电网建设的高速发展和电网事故影响的扩大,电网安全引起了各方面的高度重视.从2006年起,国家电网公司正式开展安全风险管理工作.根据风险管理的理论和电网事故的特点,系统地探讨了电网安全的风险管理并提出了改进措施,以形成安全生产预防机制,规避和化解安全风险,保障电网安全运行.     

面向对象思想在民用机场危险源辨识中的应用

运用现代安全科学的观点,提出基于认知程度的危险源分类方法,即未知危险源、已知有效管控危险源、已知未有效管控危险源。针对民用机场风险管理过程中,辨识的方法标准不统一、辨识对象的主体单一、辨识的结果口径内容泛失科学性等问题,借鉴面向对象思想的分析思路,试图解决危险源辨识工作不易把握的问题,并在具体实现上进行相应的论述,完成面向对象的危险源辨识模板类的构建。实证结果,验证了面向对象思路的可行性,为民用机场的安全风险管理工作提供了一种新方法。     

基于无线射频识别(RFID)技术的肉制品安全监控系统模糊综合评价

在无线射频识别(RFID)技术的肉制品安全监控系统中肉制品物流流程和影响因素分析的基础上,运用模糊综合评价给出主因素权重的计算原理;结合企业肉制品安全监控系统的具体情况,选择了评价指标并进行综合分析,建立了肉制品监控体系安全现状评价模型;在确定因素权重时,采用定性和定量相结合的层次分析法(AHP),其结果表明:权重的赋值科学合理,较好地反映了各因素对企业安全程度的重要程度和评判等级,所建立的多层次评价体系客观地反映了肉制品企业的安全状况,对肉制品加工企业安全监控具有重要的参考价值。     

化学品混合物的安全监管技术研究

从分析我国化学品混合物安全监管技术出发,研究对比我国和国外在化学品混合物的危险性鉴别与分类、命名以及名录收入形式等安全监管技术方面的不同做法;指出我国在混合物危险性鉴别与分类、命名以及名录收入形式方面的缺陷和不足;提出完善化学品混合物安全监管技术是提高我国化学品混合物安全监管水平的重要手段;认为借鉴欧盟RAECH、联合国《关于危险货物运输的建议书-规章范本》及GHS的先进做法制定化学品混合物技术名称命名规则、修订现行危险化学品名录中混合物条目、引进混合物健康及环境危害估算方法,对提高我国化学品混合物的安全监管技术水平,促进化学品混合物的安全监管具有重要现实意义。     

离子选择电极法测定水中氯化物

采用离子选择电极法测定水中氯化物,通过试验确定参比溶液、离子强度调节剂的配制,并用添加氯离子氧化剂和离子浓度调节剂的方法排除干扰离子对测定的影响,使得复合氯离子电极测得的能斯特曲线响应系数为93．2％。标准品的加标回收率为99．8％±0．6％,测定结果的 RSD为0．4％。用该方法与国标硝酸银滴定法同时测定实际水样,两方法的测定值绝对误差在允许范围内。     

MnOX/ACF低温选择性催化还原烟气中的NO

进行了MnOX/ACF(活性炭纤维)对低温选择性催化还原(SCR)NO的影响研究.实验表明,ACF先经浓酸预氧化,然后再负载MnOX催化剂,对NO脱除率的提高较明显,并且以20%(质量分数)HNO3预氧化处理的效果最佳.比较了相同制备条件和相同负载量下的MnOX/ACF和V2O5/ACF的催化效果,认为在同等条件下MnOX的活性高于V2O5.考察了不同负载量的MnOX对NO脱除率的影响,较理想的MnOX负载量为12%(质量分数).在此基础上就不同的催化剂质量和烟气流速比(W/F)对NO脱除率的影响进行了研究,结果表明,在低温、W/F为2～3 mg/(mL·min-1)时NO的去除率较高.     

Spatial variations in selected metal contents and particle size distribution in an urban and rural atmosphere of Islamabad, Pakistan

Spatial variations in total suspended particulate matter (TSP) were investigated for distribution of metals and particle size fractions in the urban and rural atmosphere of Islamabad, Pakistan. The metals Na, K, Fe, Mn, Pb, Cd, Cr, Zn, Ni and Co, and the particle fractions <2.5, 2.5-10, 10-100 and >100 microm were included in the study. TSP samples were trapped on glass fibre filters using high volume samplers and quantification of metals was done using Atomic Absorption Spectrometry employing HNO(3) based wet digestion. At the urban site, Na was dominant at 2.384 microg/m(3) followed by K, Fe and Zn with 0.778, 0.667 and 0.567 microg/m(3) as mean concentrations, respectively. The metal levels for the rural site ranged from 0.002 microg/m(3) for Cd to 1.077 microg/m(3) for Na. However, compared with the urban site, mean Pb concentration showed an almost two-fold enhancement, i.e., 0.163 Vs. 0.327 microg/m(3). Metals and particle size source identification was done using Principal Component Analysis and Cluster Analysis. Five sources were traced out for the urban site: industrial, soil, automobile emissions, metallurgical industries and excavation activities. For the rural site, four sources were recorded: agricultural, automotive emissions, excavation activities and metallurgical units. Collectively, for both the sites, PM(10-100) emerged as a major contributor to TSP, followed by PM(2.5-10), PM(<2.5) and PM(>100) in that order. The metals showed in general positive relationship with fine particulate fractions (PM(2.5-10), PM(<2.5)), and negative correlation with coarse fractions (PM(10-100), PM(>100)). Comparison with the corresponding data from various Asian sites revealed that the levels of Na, K, Fe, Mn, Co and Ni for the present study were lower than those reported for grossly polluted cities of the world.     

结构损伤诊断与系统时域辨识研究综述

对结构时域辨识理论及其应用进行系统研究和综述。研究表明:环境激励的非平稳与不确定性、响应信息的不完备性、反问题的不适定性以及测试噪声等是影响系统时域辨识理论在结构损伤诊断中应用的关键因素。以影响因素为主线,系统阐述结构时域辨识理论、方法的发展和研究现状,并对其优、缺点进行比较。分析指出,基于系统识别的结构损伤诊断技术适合于从整体层次上把握结构的健康状况,只有将其与局部损伤检测方法结合才有可能对大型复杂结构的健康状况作出正确的评估。展望结构时域辨识技术的发展趋势认为:随机子空间法等先进的系统辨识方法、EMD非平稳信号处理技术以及神经网络智能算法将成为未来研究和发展的主流。     

Real-time contaminant detection and classification in a drinking water pipe using conventional water quality sensors: Techniques and experimental results

Accurate detection and identification of natural or intentional contamination events in a drinking water pipe is critical to drinking water supply security and health risk management. To use conventional water quality sensors for the purpose, we have explored a real-time event adaptive detection, identification and warning (READiw) methodology and examined it using pilot-scale pipe flow experiments of 11 chemical and biological contaminants each at three concentration levels. The tested contaminants include pesticide and herbicides (aldicarb, glyphosate and dicamba), alkaloids (nicotine and colchicine), E. coli in terrific broth, biological growth media (nutrient broth, terrific broth, tryptic soy broth), and inorganic chemical compounds (mercuric chloride and potassium ferricyanide). First, through adaptive transformation of the sensor outputs, contaminant signals were enhanced and background noise was reduced in time-series plots leading to detection and identification of all simulated contamination events. The improved sensor detection threshold was 0.1% of the background for pH and oxidation–reduction potential (ORP), 0.9% for free chlorine, 1.6% for total chlorine, and 0.9% for chloride. Second, the relative changes calculated from adaptively transformed residual chlorine measurements were quantitatively related to contaminant-chlorine reactivity in drinking water. We have shown that based on these kinetic and chemical differences, the tested contaminants were distinguishable in forensic discrimination diagrams made of adaptively transformed sensor measurements.     

地铁车站基坑工程建设风险识别与预控

为满足城市交通需求,近几年城市地下轨道工程建设发展迅猛。由于地下工程施工受到地质条件及周围环境的影响,施工风险比地面工程要复杂得多,为避免施工事故发生导致巨大损失,对施工进行风险分析和制定预控措施是非常有必要的。结合南京地铁2号线一期工程车站基坑工程,对地铁车站基坑工程的建设施工风险进行了识别。在风险识别的基础上,运用风险指数法对风险进行了分析评估,确定了风险发生的概率以及影响的大小。结合工程建设实践经验、专家分析以及相关理论,提出地铁车站基坑工程施工中一些典型风险和基坑范围内管线安全风险的预控措施。