Characteristics of aerosols collected in central Taiwan during an Asian dust event in spring 2000

Aerosol samples for PM(2.5) and PM(2.5-10) were collected at four locations in central Taiwan from 26 to 31 March 2000, a period that experienced exceedingly high PM levels from 29 to 30 March due to the passage of an Asian dust storm. The samples were analyzed for mass, metallic elements, ions, and carbon. The purpose of this paper is to investigate the influence of the dust storm on the characteristics of local ambient particulate matter. The results indicate that the concentrations of the crustal elements Ca, Mg, Al, Fe and the sea salt species Na+ and Cl- in PM(2.5-10) during the dust episode exceed the mean concentrations in the non-dust period by factors of 3.1, 2.9, 2.6, 2.2, 2.3 and 2.1 respectively. Enrichment factors of Ca, Fe, and Mg in PM(2.5-10) during the dust event are close to unity, indicating that these elements are from soil. Reconstruction of aerosol compositions revealed that soil of coarse particulates elevated approximately 50% in the dust event. It is noted that during the dust event, the ratio of Mg/Al in PM(2.5-10) ranged from 0.21 to 0.25 while that of Ca/Al ranged from 0.6 to 0.9, levels more constant than those obtained in non-dust period.     

基于保护生态的土壤基准值制订关键技术研究——以美国和澳大利亚为例

土壤环境基准是土壤环境质量标准制修订、土壤环境质量评价和监管的重要科学依据.笔者选取美国和澳大利亚基于保护生态的土壤基准制订中的关键技术进行深入讨论,从两国的制订策略和关键推导方法等方面进行详细阐述,比对了两国的基准值制订技术要点.结果表明,两国的土壤基准名称、保护对象和毒理数据处理措施等存在差异,这与各国的具体制定策...     

Performance and mechanism of Cr(VI) removal by zero-valent iron loaded onto expanded graphite

Zero-valent iron (ZVI) was loaded on expanded graphite (EG) to produce a composite material (EG-ZVI) for efficient removal of hexavalent chromium (Cr(VI)). EG and EG-ZVI were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller (BET) analysis. EG-ZVI had a high specific surface area and contained sub-micron sized particles of zero-valent iron. Batch experiments were employed to evaluate the Cr(VI) removal performance. The results showed that the Cr(VI) removal rate was 98.80% for EG-ZVI, which was higher than that for both EG (10.00%) and ZVI (29.80%). Furthermore, the removal rate of Cr(VI) by EG-ZVI showed little dependence on solution pH within a pH range of 1–9. Even at pH 11, a Cr(VI) removal rate of 62.44% was obtained after reaction for 1 hr. EG-ZVI could enhance the removal of Cr(VI) via chemical reduction and physical adsorption, respectively. X-ray photoelectron spectroscopy (XPS) was used to analyze the mechanisms of Cr(VI) removal, which indicated that the ZVI loaded on the surface was oxidized, and the removed Cr(VI) was immobilized via the formation of Cr(III) hydroxide and Cr(III)–Fe(III) hydroxide/oxyhydroxide on the surface of EG-ZVI.     

Dobbins-Camp水质模型的修正

对多宾斯 坎普 (Dobbins Camp)水质模型进行了修正 ;并分别运用传统多宾斯 坎普模型和修正模型 ,对某河段实测资料进行BOD、D(氧亏 )计算 ,比较两者之间的异同 ,及分析溶解氧对有机物降解的影响     

固定化生物活性炭快速启动处理微污染水

通过固定化手段,将筛选出来的优势菌种应用于生物活性炭挂膜过程,形成固定化生物活性炭(IBAC),加速挂膜过程,并用于微污染水的处理。研究结果表明,自然挂膜需要24 d,而采用固定化微生物9 d挂膜完成,对氨氮去除率达到90%,微生物挂膜时间缩短了60%。IBAC表面的微生物数量高于自然挂膜BAC微生物量,并且沿着水流方向微生物量逐渐减少。微生物镜检发现,运行3个月的IBAC表面出现大量菌胶团、轮虫和钟虫等原生和后生动物。IBAC具有较快的启动挂膜性能和较好的微污染水处理效果。     

宁波台地倾斜在皎口地震活动中的前兆反应特征

通过对宁波台地倾斜近几年来观测资料的分析，发现其在皎口几组地震事件前有不同程度的异常反应。在分量图上，震前出现了短临期前兆异常反应特征，并且有异常时间越长，幅度越大，地震震级就越高的特点。此外还对异常出现的成因作了探讨     

基于AHP-CRITIC的电梯安全性评估

针对电梯安全评估方法中指标权重主观性大的问题,为提高评估结果的科学性,综合AHP法、CRITIC法和模糊综合评价理论,建立了电梯安全性评估模型。从设备情况、使用情况、人员管理3个方面出发,构建了电梯安全性评估指标体系。采用AHP法,根据专家经验构造判断矩阵,得到指标的主观权重。采用CRITIC法,计算同一指标的对比强度和指标间的冲突性,得到指标的客观权重。通过加权求和的方式,兼顾主客观权重,得到指标的综合权重。基于模糊综合评价法,应用"升半梯形分布"对各级指标构造模糊评估矩阵,并量化评估结果向量。以南京市某电梯为实例,应用该模型得出此电梯的安全值为68.8,安全等级为"较安全",与此电梯的实际情况相符;并与其他方法所得的评估结果进行比较,进一步验证了该模型的正确性和有效性。     

乙酰丙酮荧光法在线监测环境空气中的甲醛

我国现行环境空气中甲醛的标准测定方法普遍难以满足当前大气监测中对痕量浓度水平甲醛的监测需要.在乙酰丙酮分光光度法的基础上改进得到的乙酰丙酮荧光法具有更低的检出限和更高的灵敏度,适用于大气中痕量浓度水平甲醛的监测.基于乙酰丙酮荧光法设计了甲醛在线监测系统,并对其主要性能指标进行了评估测试.测试结果显示,该系统的吸收效率为...     

UV-B辐射增强对冬小麦生长发育及产量的影响

研究了大田栽培条件下紫外辐射增强对冬小麦孕穗、抽穗、开花、灌浆、结实以及产量的影响。结果表明,UV B辐射增强使小麦植株矮化,叶面积减小,穗重、茎重、叶重减小,灌浆速度变慢,灌浆不充实,此外,UV B辐射增强还使花粉败育率增大。