The indirect involvement of buses in traffic accident processes

The involvement of buses in accidents usually is assessed implicitly on the basis of the direct involvement of the bus in the collision or in injury production. This paper deals with the scope and forms of indirect involvement of buses (as a sight obstruction, for example). Accidents were selected by identifying the presence of the term ‘bus’ or synonyms in the text parts of complete police reports (testimonies, statements by the persons involved, etc.) available in electronic form, then analysed in detail. Direct or indirect involvement of a bus is found in 3.6% of traffic injury accidents reported by the police in the community studied (direct involvement: 1.4%; indirect involvement: 2.2%). The different forms of indirect involvement are then described, and some possibilities of preventive measures are discussed.     

大连电厂2号炉350 MW机组电除尘器增效改造

详细介绍了华能大连电厂一期工程2号炉电除尘器增效改造的方法和取得的良好效果。     

沉水植物对富营养化水体的净化效果研究

通过建立小型围隔区,研究了沉水植物对富营养化水体中氮、磷等污染物的净化效果,以及对底泥中磷含量的影响.结果表明:(1)在放养沉水植物的围隔水体中各种营养盐浓度明显低于对照围隔;(2)沉水植物对磷的吸收能够有效地保持底泥中磷的含量,而在对照围隔中的底泥中磷元素含量却不断增加;(3)经50天后,水体中TN、NH4 -N、TP、PO43--P和CODMn平均去除率分别为36.3%、70.5%、54.6%、65.4%和43.1%.     

A Parallel Study of SAR Levels in Head Tissues for Three Antennas Used in Cellular Telephones: Monopole, Helix and Patch

Summary This paper is a comparative study of several antennas commonly used in cellular telephones. These include a monopole, a helix-monopole and a patch antenna. Each one of these structures is modeled and numerically tested using finite-difference time-domain simulation and human models based on magnetic-resonance images, which allow for inclusion of details of the human body in the simulation. The testing procedure involves antenna simulation in the proximity of the human head. The behavior of each antenna is evaluated for variable distances from the head geometry (0, 1, 2, 4, 8 and 16 mm). Continuous waveform, representative of the sources used in mobile telephones, (250 mW, 1.8 GHz) is used as the form of the antenna excitation. The simulation outputs used as measures for this comparative study include transmitting and receiving antenna characteristics and the specific absorption rate (SAR). The SAR levels for the head tissues are calculated for and with accordance to the two currently accepted standards: Federal Communications Commission (FCC) and International Commission on Non-Ionizing Radiation Protection (ICNIRP). The computed SAR levels within each of the considered tissues vary for the three antennas under investigation and are within the determined health safety standards. Results suggest that the patch antenna may be the structure of choice when considering safety standards, as its radiation yields the lowest local SAR in the head tissues.     

ARE RURAL RESIDENTS WILLING TO PAY ENOUGH TO IMPROVE DRINKING WATER QUALITY?1

ABSTRACT: The concentrations of iron and sulfate in community water supplies are a concern for a number of areas in southwestern Minnesota. This study used the contingent valuation method to determine how much consumers would be willing to pay to improve their drinking water quality. On average, individuals were willing to pay US$5.25 per month (in 1995 U.S. dollars) to reduce the level of iron and US$4.33 per month to reduce the level of sulfate in their water to the USEPA's secondary standards for drinking water quality. Respondents with negative perceptions of their drinking water quality were willing to pay more to improve water quality. The aggregate annual willingness to pay (WTP) for all consumers in community water systems in southwestern Minnesota that were out of compliance with water quality standards were estimated to be US$2.4 million and US$2.0 million (in 1995 dollars) for reducing the levels of iron and sulfate, respectively. Yet the total WTP of consumers who use small community water systems may not be enough to pay the full cost of providing improved water in those systems. Economies of scale in water treatment and difficulties in financing improvements mean that technical innovation, government assistance, or institutional changes may be needed to improve water quality in these areas.     

不同环境体系下锂离子电池热失控特性实验研究

针对锂离子电池热失控引发的航空运输安全问题,自主设计并搭建锂离子电池热失控灾害演化及危险性分析实验平台。在敞开和密封环境体系下,对电加热触发荷电量(State of Charge,SOC)为0%、50%和100%的18650型锂离子电池热失控规律进行了实验研究。观察单体锂离子电池在敞开和密封体系中的热失控现象,并记录单体锂离子电池热失控时间、温度峰值及相应的温度变化。数据结果显示,相比敞开体系,密封体系有效的延缓了锂离子电池发生热失控的时间,并降低了锂离子热失控时释放的能量,为锂离子电池的航空运输安全性研究提供了理论依据和工程技术参考。     

海外核电工程安全文化建设的实践

安全文化是企业文化的重要组成部分,有效的安全文化建设,对企业文化的管理和运行具有良好的促进作用。文章以海外核电某项目部的文化建设为例,以文化体系建设的安全文化管理模式、安全文化教育模式、安全文化检查模式、安全文化宣传模式、安全文化激励模式、安全文化科技模式、安全文化技能模式和安全文化专题模式来探讨海外核电某项目在安全文化建设的具体做法,为其他海外工程项目提供借鉴,不断提升企业软实力,提高中国核电走出去的安全管理水平。     

火灾科学需深入研究的课题探讨

火灾科学是系统的科学,它涉及多个技术领域。从科学发展和现实角度,提出当前的火灾科学在城市消防规划、高大空间建筑防火设计综合方法、多层地下交通枢纽防火研究、安全疏散心理和机理研究、火灾自动报警系统的关联研究、建筑防排烟技术研究、建筑结构耐火性能研究等10个技术领域需深入研究的课程,以最终实现基础理论、实用方法、先进技术和科学管理一体化。     

安全科学学科建设理论研究

安全科学是一门新兴的大交叉综合学科,为促进安全科学的快速发展,运用科学学思想和知识溯源等方法,从安全学科建设的高度,首先阐述交叉科学的属性、研究层次、交叉形式、知识命名和现有交叉科学研究存在的问题,在此基础上提出了安全科学研究的创新思路、安全科学研究的多视角与分类和安全科学研究成果的多样性特征,最后给出了安全科学新分支创建的实例。研究结果表明:只有了解交叉学科的基础问题,才能理解安全科学的发展,才能快速地创新安全科学。     

新时期城市安全风险防控实践探析——以成都为例

随着我国加快从"乡村社会"迈向"城市社会",城市安全问题成为了新时期亟待解答的"国家命题",分析了城市化与城市风险相关问题,提出了适合成都的安全风险预防指标体系,并以"技术防控"开发建设城市安全监测预警系统,以"标准防控"推动企业和公共领域安全管理标准化,以"群众防控"依托安全社区为载体,构建基层社区公共安全体系,为我国城市安全风险防控体系建设提供了宝贵经验和有益启示。