空间环境下碳纤维/双马树脂基复合材料的性能演化及损伤机理

目的基于碳纤维/双马树脂基(CF/BMI)复合材料在航天结构材料中广泛的应用前景,研究其性能演化及损伤机理,为评估与预测其在空间环境下的服役性能及寿命提供理论依据。方法利用地面试验装置模拟不同的空间环境因素包括真空热循环、质子辐照和电子辐照,利用动态力学分析(DMA)、热重分析(TGA)、X射线光电子能谱(XPS)、热膨胀分析、原子力显微镜(AFM)和力学性能测试等手段系统地研究CF/BMI复合材料在空间环境下的性能变化及损伤行为。结果真空热循环能够引发复合材料产生脱气行为与界面脱粘效应,使其横向拉伸强度退化,弯曲强度和层间剪切强度受到热循环初期固化交联作用的影响,呈现先升高后降低的变化趋势。质子辐照导致材料表面层化学键断裂及碳化,使力学性能及热性能受到一定程度的损伤。电子辐照能够引发辐照交联和辐照降解作用,在较高束流量辐照下降解作用占据主导地位成为复合材料力、热性能退化的决定性因素。结论预期研究成果为CF/BMI复合材料在空间环境下的服役性能及寿命的评估与预测提供了必要的理论依据。     

南京市大气PM2.5无机组分及对A549细胞的毒性效应

为研究不同来源的大气颗粒物中PM_2.5对人体的健康毒性效应,于2016年1-3月在南京市交通源区、化工园区、生活区等代表性站点分别采集PM_2.5样品,分析其水溶性离子和金属元素含量,并以PM_2.5对人体肺上皮细胞A549染毒24 h,研究暴露于不同来源颗粒物后的细胞活性和氧化损伤程度.结果表明:交通源区和化工园区日均ρ（PM_2.5）远高于生活区,3个区域均含有大量二次污染物,其中SO₄2-、NO₃-和NH₄+占PM_2.5总离子质量的80.6%~85.0%.交通源区PM_2.5中w（Zn）较高,主要来源于燃料燃烧和柴油发动机排放;而化工园区PM_2.5中w（Cu）、w（Pb）和w（Mn）均高于其他站点.将PM_2.5染毒剂量设定为50、100、200、400 μg/mL,各站点颗粒物均显著抑制A549细胞的存活率,并呈剂量-效应关系,化工园区对细胞存活率的半抑制浓度（IC₅₀=229.1 μg/mL）最低,而在高暴露浓度（200 μg/mL）下化工园区诱导产生的活性氧（ROS）最少.因此,南京地区主要受二次污染影响,机动车污染正在加剧;化工园区的颗粒物具有较大的细胞毒性,而较低的氧化损伤程度可能与该站点颗粒物中较低的w（Zn）以及测试暴露时间有关.      

Speciation analysis of aluminium in plant parts of Betula pendula and in soil

The research presents the first results of aluminium speciation analysis in aqueous extracts of individual plant parts of Betula pendula and soil samples, using High Performance Ion Chromatography with Diode Array Detection(HPIC-DAD). The applied method allowed us to carry out a full speciation analysis of aluminium in the form of predominant aluminium–fluoride complexes: AlF_((x = 2,3,4))~((3-x))(first analytical signal), AlF~(2+)(second analytical signal) and Al~(3+)(third analytical signal) in samples of lateral roots, tap roots, twigs, stem, leaf and soil collected under roots of B. pendula. Concentrations of aluminium and its complexes were determined for two types of environment characterised by different degree of human impact:contaminated site of the Chemical Plant in Luboń and protected area of the Wielkopolski National Park. For all the analysed samples of B. pendula and soil, AlF_((x = 2,3,4))~((3-x))had the largest contribution, followed by Al~(3+)and AlF~(2+). Significant differences in concentration and contribution of Al–F complexes and Al~(3+)form, depending on the place of sampling(different anthropogenic pressure) and plant part of B. pendula were observed. Based on the obtained results, it was found that transport of aluminium is "blocked" by lateral roots, and is closely related to Al content of soil.     

Mechanisms of ultraviolet disinfection and chlorination of Escherichia coli: Culturability, membrane permeability, metabolism, and genetic damage

Traditional culture methods may underestimate the tolerance of microorganisms to disinfectants because of the existence of viable but nonculturable or sublethally injured cells after disinfection.The selection of a strict method is crucial for the evaluation of disinfection performance.The actions of 2 typical disinfectants–ultraviolet(UV)and chlorine–on the fecal indicator Escherichia coli were investigated by the detection of culturability,membrane permeability,metabolic activity,deoxyribonucleic acid(DNA),and messenger ribonucleic acid(m RNA).During UV disinfection,the irreversible damages in the cell membrane and cellular adenosine triphosphate(ATP)were negligible at low UV doses(80 m J/cm~2).However,membrane permeability was damaged at low doses of chlorine(5 mg/L),leading to leakage of cellular ATP.Our study showed that a slight lesion in DNA was detected even at high doses of UV(400 m J/cm~2)and chlorine(5 mg/L)treatments.The decay of m RNA was more rapid than that of DNA.The degradation level of m RNA depended on the choice of target genes.After exposure to 50 m J/cm~2UV dose or 5 mg/L chlorine for30 min,the DNA damage repair function(Rec A m RNA)was inhibited.The m RNA involved in the DNA damage repair function can be a potential indicator of bacterial viability.     

北京大气PM_(2.5)对A549细胞炎性因子及DNA损伤的毒性

为探讨大气PM_(2.5)及其不同组分对人肺上皮细胞A549的毒性作用及其剂量-反应关系,将前期采集的PM_(2.5)颗粒物用不同方法进一步制备PM_(2.5)水溶性组分、PM_(2.5)脂溶性组分和PM_(2.5)单纯颗粒物,将制备的PM_(2.5)颗粒物及其组分以不同浓度(10,50,100,200,400μg/m L)对A549细胞染毒,用MTS法分别在染毒6,10,24,48,72h后测定细胞活力,染毒24h后用ELISA及RT-QPCR法测定炎性因子IL-6和TNF-α表达量,AP位点计数法测定细胞DNA损伤情况.结果表明:除PM_(2.5)水溶性组分外,其余染毒样本高浓度染毒时始终对细胞生长表现出抑制作用,其中低浓度染毒时可在较短时间对细胞生长表现出抑制作用,染毒时间较长时抑制作用减弱或消失,PM_(2.5)水溶性组分对细胞生长抑制作用并不显著;除PM_(2.5)水溶性组分外,其余染毒样本都显著升高了IL-6m RNA的相对表达量和IL-6蛋白的分泌,除PM_(2.5)脂溶性组分外,其余染毒样本都显著升高了TNF-αm RNA的相对表达量;除PM_(2.5)水溶性组分外,其余染毒样本都显著提高了DNA碱基缺失程度.总的来说,PM_(2.5)水溶性组分在抑制细胞活力、造成炎性损伤及DNA损伤方面作用相对较小,而PM_(2.5)所产生的毒性作用并不仅限于其所吸附的复杂成分,其中作为载体的固体核心颗粒对机体可能造成的毒性作用也不容忽视.     

净水厂应对水源地突发苯胺污染处理能力研究

通过对粉末活性炭(PAC)的改性研究提高净水厂对苯胺突发污染的应急能力。以松花江水源地为实验用水,以苯胺污染为研究对象,采用PAC吸附工艺对净水厂应对苯胺突发污染的能力进行了系统研究。结果表明,由于原水中NOM存在的竞争吸附作用,当苯胺超标5倍时,需要PAC投加量130 mg/L才能使出水达标,但对出水浊度产生不利影响;经KOH改性的PAC,在不影响出水浊度的投加量为80 mg/L时就能处理超标5倍的苯胺。     

Past and Present Effectiveness of Protected Areas for Conservation of Naturally and Anthropogenically Rare Plant Species

Abstract:  The Global Strategy of Plant Conservation states that at least 60% of threatened plant species should be within protected areas. This goal has been met in some regions with long traditions of plant protection. We used gap analysis to explore how particular groups of species of conservation interest, representing different types of natural or anthropogenic rarity, have been covered by protected areas on a national scale in Estonia during the last 100 years. Species-accumulation curves indicated that plant species that are naturally rare (restricted global or local distribution, always small populations, or very rare habitat requirements) needed almost twice as many protected areas to reach the 60% target as plant species that are rare owing to lack of suitable management (species depending on grassland management, moderate forest disturbances, extensive traditional agriculture, or species potentially threatened by collecting). Temporal analysis of the establishment of protected areas suggested that grouping plant species according to the predominant cause of rarity accurately reflected the history of conservation decision making. Species found in very rare habitats have previously received special conservation attention; species dependent on traditional extensive agriculture have been largely ignored until recently. Legislative initiative and new nature-protection schemes (e.g., Natura 2000, network of protected areas in the European Union) have had a positive influence on all species groups. Consequently, the species groups needing similar action for their conservation are sensitive indicators of the effectiveness of protected-area networks. Different species groups, however, may not be uniformly conserved within protected areas, and all species groups should fulfill the target of 60% coverage within protected areas.     

Evaluation of soil characteristics potentially affecting arsenic concentration in paddy rice (Oryza sativa L.)

Paddy rice may contribute considerably to the human intake of As. The knowledge of soil characteristics affecting the As content of the rice plant enables the development of agricultural measures for controlling As uptake.During field surveys in 2004 and 2006, plant samples from 68 fields (Italy, Po-area) revealed markedly differing As concentration in polished rice. The soil factors total As_{(aqua regia)}, pH, grain size fractions, total C, plant available P_(CAL), poorly crystalline Fe_(oxal.) and plant available Si_(Na-acetate) content that potentially affect As content of rice were determined.A multiple linear regression analysis showed a significant positive influence of the total As_{(aqua regia)} and plant available P_(CAL) content and a negative influence of the poorly crystalline Fe_(oxal.) content of the soil on the As content in polished rice and rice straw.Si concentration in rice straw varied widely and was negatively related to As content in straw and polished rice.     

关于影响易损性分析结果的区域因素研究——以福建为例

以福建省震害快速评估系统为依托,以分析处理现场实际调查数据为基础,提出了主要影响易损性分析结果的四个区域因素及其影响指数值、区域综合指数值,提供了各分区的划分依据、各分区影响指数值的评定标准以及区域综合指数值的计算方法,为合理应用不同地区之间的易损性矩阵或易损性曲线提供了参考依据。     

油气管道第三方施工损伤风险控制方法研究

针对当前油气管道运行的现状指出第三方施工损伤风险控制的紧迫性,根据第三方施工损伤风险辨识的内容,以及油气管道第三方施工损伤风险评估中人为因素分析理论,阐述第三方施工损伤风险的影响因素,通过计算各因素的灰色关联度辨识出了第三方损伤风险的主控因素,并提出了第三方施工损伤风险控制方法.