桥梁结构抗爆安全评估研究进展

随着恐怖袭击和偶发爆炸事故造成的桥梁爆炸事故不断增多,桥梁结构抗爆安全问题越来越受到关注。本文中系统总结了桥梁结构抗爆安全评估的研究进展,分析桥墩、桥面、桥索和桥塔爆炸载荷作用下桥梁的理论简化方法和结构的动力响应,和桥梁的连续性、冗余性和鲁棒性对结构连续性倒塌的影响,通过对建筑和桥梁抗连续倒塌的研究现状及相关规范的归纳,明确了桥梁连续倒塌的特性及现行桥梁设计方法的缺陷。而后,就承载能力评估、耐久性评估和适用性评估等桥梁安全评估问题的研究进展进行了梳理,并对桥梁爆破拆除技术和近地下爆炸对桥梁产生的响应和破坏作用进行分析,并针对当前研究的现状,分别提出建议。     

一种光源的蓝光危害与节律效应可视化评估方法

为了使基层质检人员经济快速的评估光源蓝光危害与节律效应,测量了六种常见人工照明和三种显示器的光谱分布,结合QB5型钴蓝玻璃片的透射率,对九种光源透过QB5型钴蓝玻璃片的光谱分布进行计算分析,研究了光源蓝光危害因子和节律因子与1931 CIE-XYZ色坐标Z值、透过钴蓝玻璃片的主波长及明视觉光通量的关系;以人眼对波长及亮度变化的分辨力为依据,验证了以烛光为参照,根据人眼透过QB5型钴蓝玻璃片观察到的光源亮度,对光源蓝光危害与节律效应进行可视化评估的可行性。结果表明：九种光源的蓝光危害因子和节律因子均随色坐标Z值、透过钴蓝玻璃片的主波长及明视觉光通量的增大而增加;该可视化评估方法可行。研究方法与结果可为光生物安全评估与相关仪器设备开发提供参考。     

Recent Advances in the Application of the Antimicrobial Peptide Nisin in the Inactivation of Spore-Forming Bacteria in Foods

Conventional thermal and chemical treatments used in food preservation have come under scrutiny by consumers who demand minimally processed foods free from chemical agents but microbiologically safe. As a result, antimicrobial peptides (AMPs) such as bacteriocins and nisin that are ribosomally synthesised by bacteria, more prominently by the lactic acid bacteria (LAB) have appeared as a potent alternative due to their multiple biological activities. They represent a powerful strategy to prevent the development of spore-forming microorganisms in foods. Unlike thermal methods, they are natural without an adverse impact on food organoleptic and nutritional attributes. AMPs such as nisin and bacteriocins are generally effective in eliminating the vegetative forms of spore-forming bacteria compared to the more resilient spore forms. However, in combination with other non-thermal treatments, such as high pressure, supercritical carbon dioxide, electric pulses, a synergistic effect with AMPs such as nisin exists and has been proven to be effective in the inactivation of microbial spores through the disruption of the spore structure and prevention of spore outgrowth. The control of microbial spores in foods is essential in maintaining food safety and extension of shelf-life. Thus, exploration of the mechanisms of action of AMPs such as nisin is critical for their design and effective application in the food industry. This review harmonises information on the mechanisms of bacteria inactivation from published literature and the utilisation of AMPs in the control of microbial spores in food. It highlights future perspectives in research and application in food processing.     

锂离子电池安全性添加剂*

作为锂离子电池的一个重要组成部分,电解质对电池的性能有重要影响。有机电解液功能添加剂是近年来锂离子电池研究中的一个热点。本文介绍了锂离子电池有机电解液阻燃剂和过充电保护剂改善电池安全性的作用机理、特点以及它们的研究应用现状,并对各种添加剂的优缺点作了简要评价。     

Fire‐safe agent integrated with oyster shell and melamine polyphosphate for thermoplastic polyurethane

At present, thermoplastic polyurethane (TPU) is widely used, but there are still many defects in fire safety, such as burning with heavy smoke and dripping. In this article, OS@MP was synthesized by modifying oyster shell (OS) powder with melamine polyphosphate (MP) and then served as fire‐safe agent for TPU. The fire performance of TPU composites were investigated using microscale combustion colorimeter (MCC), cone calorimeter test (CCT), smoke density test (SDT), and thermogravimetric analysis/Fourier transform infrared (TG‐FTIR) spectrum analysis. The MCC and CCT results revealed that OS@MP could reduce the fire hazards of TPU composites. The peak heat release rate (pHRR) of the sample with 10.0 wt% OS@MP decreased to 170.86 kW/m² from 1772.37 kW/m² for pure TPU. And, the SDT results showed that OS@MP could significantly reduce the smoke production of TPU composites. The TG‐FTIR also confirmed that the noncombustible gases (including CO₂, ammonia, and water vapor) produced by OS@MP have played a reinforcing role in TPU composites as well as a char formed on the surface of composites, which could act as a barrier to prevent the heat and air, reinforce the fire safety of TPU.     

Effects of emulsifying agents on the safety of titanium dioxide and zinc oxide nanoparticles in sunscreens

The use of titanium oxide (TiO₂) and zinc oxide (ZnO) nanoparticles (NPs) in sunscreen formulations has increased considerably, and might pose a serious health hazard worldwide. A thorough investigation into the toxicity induced by such components is highly necessary. In this study, the effects of TiO₂ and ZnO NPs on HaCaT cells were tested in the presence and absence of emulsifiers (cyclopentasiloxane, jojoba ester, and lecithin). Cell viability results revealed that the toxicity of NPs was highly dose dependent and influenced by the emulsifier type. The emulsifiers themselves are minimally toxic. However, when used in combination with TiO₂ and ZnO, they were highly toxic to HaCaT cells. Transmission electron microscopy revealed that the cells showed least permeability to NPs dispersed in lecithin compared to other emulsifiers. In conclusion, the toxicity of NPs may be highly dependent on the emulsifier type and be varied. In particular, lecithin can be used as a potential alternative emulsifier in sunscreens.     

石墨烯及其衍生物在食品安全监测中的应用

综述了近年来石墨烯及其衍生物构建的传感器在食品基本组成成分、食品添加剂以及食品中残留的农药、重金属、抗生素等物质分析与监测方面的应用,并展望了石墨烯的发展与应用前景。     

化学品安全知识与应急科普宣传研究

Based on the theme of chemical awareness and safety accident response capability, this paper conducts a questionnaire survey for college students. In response to the survey results, scientific, popular, and novel offline activities/online publicity will be used to popularize chemical basics, relevant laws and regulations, and chemical safety accident emergency response methods for university students. The aim is to improve the level of understanding of various types of chemicals among college students. In the event of sudden chemical safety incidents, corrective measures can be taken, and useful information can be accurately identified after a chemical accident.     

Influence of gas compressibility on a burning accident in a mining passage

A recent predictive scenario of a methane/air/coal dust fire in a mining passage is extended by incorporating the effect of gas compressibility into the analysis. The compressible and incompressible formulations are compared, qualitatively and quantitatively, in both the two-dimensional planar and cylindrical-axisymmetric geometries, and a detailed parametric study accounting for coal-dust combustion is performed. It is shown that gas compression moderates flame acceleration, and its impact depends on the type of the fuel, its various thermal-chemical parameters as well as on the geometry of the problem. While the effect of gas compression is relatively minor for the lean and rich flames, providing 5–25% reduction in the burning velocity and thereby justifying the incompressible formulation in that case, such a reduction appears significant, up to 70% for near-stoichiometric methane–air combustion, and therefore it should be incorporated into a rigorous formulation. It is demonstrated that the flame tip velocity remains noticeably subsonic in all the cases considered, which is opposite to the prediction of the incompressible formulation, but qualitatively agrees with the experimental predictions from the literature.     

爆破地震荷载作用下承插式HDPE管道动力失效机制

承插式管道接口更易受到外界荷载破坏导致管道失效,为保证爆破开挖过程中邻近承插式高密度聚乙烯（high-density polyethylene,HDPE）波纹管道的安全运营,控制爆破振动荷载对管道的影响是重点关注内容。通过全尺度预埋单段HDPE波纹管道现场试验,得到管道的振动速度和动应变响应数据,结合LS-DYNA数值模拟软件分别建立了无承插接口管道与含弹性密封圈的承插式HDPE波纹管道;利用现场试验数据验证了无承插口管道模型参数的可靠性,并对比分析了承插式管道的结构位移、振动速度、有效应力的响应规律与失效机制;结合现行规范,根据管道响应规律与接口允许旋转角度计算得到了承插式管道的安全振动速度。研究结果表明：有承插口管道的合振速、合位移和有效应力大于无承插口管道;在同一截面上,有承插口管道迎爆侧的合振速和有效应力更大,而最大合位移出现在截面的背爆侧;管道合位移与合振速在轴线中心处截面最大,并向两端不断减小,有承插口管道中心合位移更大;通过接口允许旋转角度得到此类工况条件下的承插式管道的安全振速为24.77 cm/s。