高速公路丙烷罐车爆炸事故的后果分析

本文针对公路丙烷罐车爆炸事故的实例,对事故发生的原因进行了分析.分析结果认为,事故属于沸腾液体扩展蒸汽爆炸(BLEVE),事故对人员和财产危害包括3个方面:火球热辐射、爆炸冲击波超压和抛射碎片.本文介绍了这3种危害的数学模型和方法,并针对事故实例进行了分析和计算.结果表明,在事故发生现场100m范围内的热辐射可致人死亡或造成三度烧伤;冲击波超压在80m范围外会使玻璃破碎,但无人员伤亡;抛射碎片在334 m的范围内都可能对人体造成伤害.由此,可以得出火球热辐射是事故中最主要危害的结论.     

Observation of black carbon aerosol in Beijing, 2003

The objective of this study was to determine the black carbon concentration in Beijing in 2003. The aerosol properties were measured using an Aethalometer and a tapered element oscillating microbalance (TEOM) on the roof of the Physics Building of Peking University (39.99° N, 116.31° E) from July to August 2003 and from November 2003 to January 2004. The average black carbon (BC) concentrations in the summer and winter were 8.80 and 11.4 μg/m³, respectively. During winter, two different cyclone cut offs were installed at the inlet of an aethalometer. The BC mass concentration in TSP, PM₁₀, and PM_2.5 were obtained. The results indicated that in winter aerosol, 90% of BC exited in PM₁₀ and 82.6% of BC exited in PM_2.5. The BC in PM₁₀ accounted for 5.11% of the PM₁₀ mass.     

三阶段论：人类社会演化规律初探

本文在剖析人与自然界中的生命力系统的双螺旋进化过程及其相关主形态演化趋势的基础上，提出人类社会由生存、发展到可持续发展的“三阶段”演化学说，并依据“三种生产论”分析和评价了生存与发展阶段的特征和规律，探讨了可持续发展的内涵及其演化阶段的基本特征与行为准则     

A study of the atmospheric VOCs of Mount Tai in June 2006

Intensive field investigations were conducted at the summit of Mount Tai in June 2006 to understand the effects of the local and regional sources on atmospheric volatile organic compounds (VOCs) distributions. A total of 60 samples were collected and determined by quantitative analytical methods. The concentrations of the total VOCs (TVOCs) observed in the air of Mount Tai were 6.95 ± 5.71 ppb. Aromatic hydrocarbons provided the largest contribution to TVOCs, followed by alkanes and halocarbons. High levels of halocarbons accounted for 20% of TVOCs due to emission from a PVC plant located at the foot of Mount Tai. Alkenes and cycloalkanes contributed little to the total VOCs. The day-and-night differences and day-to-day variations in the concentrations of four selected species were investigated and the effects of several factors such as meteorological parameters, sources and transport characteristics on them were discussed in details. A back trajectory analysis showed that relatively higher levels of VOCs were related to long-range transport of pollutants from polluted areas. The vertical motions of air masses also had a large impact on the variations of the levels of VOCs. The result of the variability–lifetime relationships of VOCs, which is used to estimate the remoteness of the sampling location, showed that Mount Tai represents intermediate conditions between remote sites and sites in the vicinity of sources.     

川藏公路滑坡加固预应力锚索受力分析研究

以川藏公路102滑坡群滑坡处理为依托,仔细研究了滑坡体的工程地质特征。对由大型松散堆积物形成的2#滑坡锚索加固工程稳定性进行了研究,由于在2#滑坡中,滑动面和预应力锚索之间的夹角很大,作用在锚索上面的力还包括轴向拉力和侧向的弯矩和剪力。通过对力的分析和计算证明,使用梁单元来进行计算更加符合实际使用要求,因此,预应力锚索的应用不仅能够合理地改善结构的受力条件,并且能够充分地利用材料本身的强度特性,节约了工程的使用费用,具有很好的推广应用价值。     

基于风险分析的城市防灾减灾规划编制——以地震规划为例

为减轻城市灾害损失,提出城市防灾减灾规划编制方法,将减灾规划分为准备、风险分析、编制和实施4个步骤。依据风险分析结果,制订防灾减灾规划目标、减灾措施及策略。给出典型的地震灾害风险分析方法。以某市为例,算出其各区域的地震风险。根据风险等级划分标准确定各区域的地震风险可接受水平。基于此结果在GIS平台上的表达,可知市内旧城区的地震风险很高,须立刻采取风险减缓措施。对减灾措施进行优化,结果表明:加快现有设防不足工程的抗震加固,严抓新建工程的抗震设防水准是提高该市抗震减震能力的关键。     

焊接防护具抗热穿透性能测试仪的研制

焊接防护具是指一种保护佩戴者免受由焊接或相关作业所产生的有害光辐射及其他特定有害因素的装置。它是从事焊接与热切割作业人员必备的个体防护装备。抗热穿透性能是表征焊接防护具产品质量和安全性能的最重要技术指标之一。然而,如何快速、便捷、节能、准确地对焊接防护具抗热穿透性能进行检测,是迫切需要解决的技术难题。本文在简要分析国内外眼面部防护标准中抗热穿透性能技术要求和测试方法的基础上,提出了一种测试焊接防护具抗热穿透性能的方法,并成功研制了焊接防护具抗热穿透性能测试仪。     

内质网应激在PFOS致大鼠肝损伤中的作用

通过全氟辛烷磺酸(PFOS)28 d大鼠经口染毒评价PFOS肝损伤效应,探讨内质网应激在PFOS毒效应中的作用。Wistar大鼠随机分组,分别以0 mg·kg~(-1)、5 mg·kg~(-1)和10 mg·kg~(-1)PFOS灌胃染毒28 d。HE染色观察大鼠肝脏形态改变。ELISA法测定各组丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)、碱性磷酸酶(ALP)和淀粉酶(AMY)含量变化。紫外分光光度法测定肝组织匀浆中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性变化。RT-PCR检测肝脏内质网应激标志蛋白表达水平。结果表明,PFOS造成大鼠体重降低、肝重增高(P0.05),组织切片显示肝细胞出现脂质沉积。PFOS不同剂量组大鼠ALT随暴露浓度增加,分别为(50.96±10.02)U·L~(-1)、(71.73±11.55)U·L~(-1),显著高于对照组(P0.05),AST、ALP含量与对照组相比显著上升(P0.05),高剂量组AMY水平为(833.46±63.05)U·L~(-1),与对照组相比显著降低(P0.05)。GSH-Px和SOD水平随PFOS浓度增加出现了显著降低(P0.05),而MDA水平显著升高(P0.05)。内质网应激标志蛋白表达均较对照组显著上升(P0.05)。以上结果说明PFOS可导致大鼠肝细胞损伤,其机制可能与内质网应激调控有关。     

三氯生暴露加剧高脂饮食诱导的小鼠肠道和肝脏功能损伤

三氯生(triclosan,TCS)在环境中被广泛检出,已成为重要的环境污染物,且TCS暴露能够影响机体的肠道菌群组成和脂类物质代谢过程.为了探讨TCS暴露对高脂饮食(high fat diet,HFD)诱导的肝脏功能损伤的影响及其机制,C57BL/6J小鼠随机分为正常饮食对照组、TCS组、HFD组和HFD+TCS组;首先对TCS组和HFD+TCS组小鼠进行提前一周TCS(10μg·g-1饲料)暴露,然后再同时进行6周的TCS暴露和HFD喂养.实验结束后,利用细菌特征序列对肠道菌群进行绝对定量分析,利用苏木精-伊红染色、实时荧光定量PCR、酶联免疫吸附测定、蛋白免疫印迹和流式细胞术等试验技术检测小鼠肠道和肝脏等生理变化状况.与对照组相比,TCS暴露和高脂饮食均能明显引起肠道菌群中厚壁菌门和拟杆菌门含量降低,同时引起小鼠脾脏中CD8+和CD4+T细胞比例失调,但未导致显著的肠道屏障损伤和脂多糖(lipopolysaccharide,LPS)异位;高脂饮食能够显著提高小鼠血清中丙氨酸氨基转移酶(alanine aminotransferase,ALT)、天门冬氨酸氨基转移酶(aspartate aminotransferase,AST)和甘油三酯(triglyceride,TG)的水平,而单独TCS暴露并没有引起明显的肝脏功能紊乱.与HFD组相比,HFD和TCS协同作用激活了小鼠肝脏中Toll样受体4(toll-like receptor 4,TLR4)炎症通路,造成小鼠肝脏炎症反应,并显著提高了小鼠ALT和AST水平,加剧了高脂饮食对小鼠肝脏功能的损伤.由此可知,TCS暴露通过引起小鼠肠道菌群紊乱和机体免疫响应,加剧高脂饮食诱导的小鼠肠道损伤和肝脏功能紊乱.