Oxidative capacities of size-segregated haze particles in a residential area of Beijing

The frequent haze days around the Chinese capital of Beijing in recent years have aroused great attention owing to the detrimental efects on visibility and public health. To discover the potential health efects of the haze, oxidative capacities of airborne particles collected in Beijing during haze and clear days were comparably assessed by a plasmid scission assay. Eleven water-soluble trace elements(As, Cd, Cr, Cu, Mn, Ni, Pb, V, Se, Tl, and Zn) in the size-segregated airborne particles were quantitatively analyzed by inductively coupled plasma mass spectrometry, and most of the watersoluble trace elements were found to mainly concentrate in the fine particle size of 0.56–1.0 μm. In comparison with clear days, the mass concentrations of 11 analyzed water-soluble trace elements remarkably increased during haze days, and the oxidative capacities determined by the plasmid scission assay were markedly elevated accordingly during the haze days under the same dosage of particles as for those during clear days. Water-soluble trace elements in airborne particles, such as Cu, V, and particularly Zn, were found to have significantly positive correlations with the plasmid DNA damage rates. Because Cu, V, and Zn have been considered as bioavailable elements, the evident increase of these elements during haze days may be greatly harmful to human health.     

I will not go,I cannot go: cultural and social limitations of disaster preparedness in Asia,Africa, and Oceania

While much work has been invested in addressing the economic and technical basis of disaster preparedness, less effort has been directed towards understanding the cultural and social obstacles to and opportunities for disaster risk reduction. This paper presents local insights from five different national settings into the cultural and social contexts of disaster preparedness. In most cases, an early warning system was in place, but it failed to alert people to diverse environmental shocks. The research findings show that despite geographical and typological differences in these locations, the limitations of the systems were fairly similar. In Kenya, people received warnings, but from contradictory systems, whereas in the Philippines and on the island of Saipan, people did not understand the messages or take them seriously. In Bangladesh and Nepal, however, a deeper cultural and religious reasoning serves to explain disasters, and how to prevent them or find safety when they strike.     

Stimulating flood damage mitigation through insurance: an assessment of the French CatNat system

Flood risk has increased in France in the last 20 years and is projected to increase further in the future due to climate change and increase in exposure. Since 1982, France has had a natural disasters insurance system (‘CatNat’) in place that covers flood damage. This insurance system has been combined with what are called ‘Risk Prevention Plans’ (PPRs) in order to stimulate the undertaking of flood risk mitigation measures by communities and households. However, these schemes do not provide optimal incentives for flood damage reduction. This is confirmed by the results from a survey about flood preparedness of 885 households who live in flood-prone areas in France, which are presented in this paper. Moreover, this study provides suggestions for improvement, which are assessed on their potential economic, social and political implications. Among these suggestions are increasing the effectiveness of PPRs and increasing the incentives to apply and implement PPRs; improving the monitoring of the implementation of damage mitigation measures; and the possibility to differentiate premiums and deductibles according to flood risk.     

混凝土重力坝FRP片材表面加固抗震性能研究

如何提高混凝土重力坝薄弱位置的抗震性能是国内外大坝抗震研究的热点问题。本文基于等价静力非线性方法,采用考虑混凝土细观非均匀特性的混凝土损伤模型,研究FRP片材表面加固大坝薄弱位置的抗震有效性。以2座不同形态的混凝土重力坝A、B为例,分别进行坝踵FRP片材表面加固研究和折坡处FRP片材表面加固研究,分析加固前后坝体的应力状态、裂缝扩展情况和破坏形态。数值模拟结果表明:坝踵处采用FRP片材加固可以很好地增强坝体的抗震性能,有效地抑制裂缝的产生和发展;折坡处采用FRP片材加固在一定程度上可以提高坝体的抗震性能,下游坝身加固与否对提高大坝的抗震性能影响不大。     

纯弯荷载下厚型钢结构防火涂层破损的试验研究和数值分析

厚型钢结构防火涂层因其耐火性好、性能稳定而成为最常用的防火保护形式之一,但厚型防火涂层易在地震和冲击等作用下发生破损和脱落,这将影响钢结构的抗火性能。为了认识厚型钢结构防火涂层的破损模式,本文对涂有厚型防火涂料的钢板件进行了纯弯荷载试验,运用有限元分析软件AN SY S对试验全过程进行了模拟分析,并与试验结果相对比。结果表明:受弯构件压区涂层的破损模式主要为涂层-钢板界面破损,拉区涂层的破损模式与涂层厚度有关,当涂层厚度较薄时,主要为涂层内部拉裂,涂层厚度较厚时,主要为涂层-钢板界面破损;涂层厚度越厚,界面破损出现得越早;若在涂层上贴置应变片,会使涂层的界面裂缝和横向裂缝提早出现。     

冲击爆炸作用对核电站安全壳毁伤效应研究的进展

核电站破坏后放射性燃料泄露带来的灾难性后果,使得核电站特别是核反应堆成为军事打击和恐怖袭击的重要目标之一.本文分析总结了核反应堆安全壳因弹体和飞机的冲(撞)击爆炸导致受损所涉及的关键科学问题的国内外研究进展,指出核安全壳体防护效能的研究重点主要在于:弹体“侵彻(贯穿)+爆炸”作用对双层钢筋混凝土和内衬钢板复合核安全壳结...     

年度地震重点监视防御区地震保险净费率的计算

根据我国年度地震重点监视区13年的预报结果和实际发生地震的结果,研究了这些地区地震保险净费率的计算方法。作为例子,给出了Ⅱ类地区基本烈度为Ⅵ度地区多层混凝土楼板砖结构Ⅶ度设防的建筑物的地震保险净损失率的计算结果。结果表明,我国年度地震重点监视区的地震保险净费率明显高于同类研究中不考虑其特殊地震危险性的结果。这一结果表明,中国的年度地震重点监视区是地震保险研究中应当给予特别关注的地区。     

硬岩竖井爆破损伤区探测及衬砌荷载*

为研究硬岩竖井受爆破开挖扰动的影响,依托米仓山公路隧道竖井工程,采用RSM-RCT（B）测试系统探测竖井爆破损伤区范围为1.1~1.4 m,并利用残余地质强度指标标定损伤区力学参数,将其纳入收敛约束法和数值分析中,以评估损伤区对竖井围岩及衬砌荷载的影响。研究结果表明,在硬岩竖井中开挖爆破是造成岩体损伤区的关键因素,地应力方向和大小对硬岩损伤区分布基本无影响。分析结果表明,爆破损伤区导致围岩变形增大,从而使得衬砌荷载增加,最大剪应力出现在损伤区与未破坏岩体之间的交界处,大小为16 MPa,同时靠近该位置的衬砌荷载也会变大,较深竖井可采用分区段支护,降低投资成本。研究结果可为硬岩竖井开挖荷载计算及设计优化提供一定参考。     

浅析热冲击对自增强反应器的影响

自增强反应器在服役期间,其残余应力会因开停车循环载荷作用,温度、压力的波动及管内介质发生超温分解反应引起的热冲击等因素的作用而衰减,为了比较系统地探讨热冲击引起的自增强残余应力衰减机理和管材损伤机理,本从研究管式反应器受热冲击作用时的应力响应出发,建立相应数学模型,得到了应力随时间变化曲线,应力随半径变化曲线,通过分析得出了热冲击发生时产生的动态应力和异常高温是引起残余应力松弛和材质发生相变和老化的主要原因。     

噪声污染损害赔偿中污染程度的认定

本文以秦皇岛市大里营村11户村民诉北京铁路局噪声污染一案为例,分析《噪声污染防治法》关于环境噪声污染的规定在适用中存在的问题,建设立法修改或出台司法解释,以保障公民的环境权。