Ozone artifacts and carbonyl measurements using Tenax GR, Tenax TA, Carbopack B, and Carbopack X adsorbents

Four popular thermally desorbable adsorbents used for air sampling (Tenax TA, Tenax GR, Carbopack B, and Carbopack X) are examined for the potential to form artifacts with ozone (O3) at environmental concentrations. The performance of these adsorbents for the ketone and aldehyde species identified as O3-adsorbent artifacts was also characterized, including recovery, linearity, and method detection limits (MDLs). Using gas chromatography/mass spectrometry, 13 different artifacts were identified and confirmed for both Tenax TA and Tenax GR, 9 for Carbopack B, but none for Carbopack X. Several O3 artifacts not reported previously were identified, including: pentanal, 3-hexanone, 2-hexanone, hexanal, 3-heptanone, and heptanal with Tenax TA; pentanal, 3-hexanone, 2-hexanone, hexanal, and 3-heptanone on Tenax GR; and 1-octene and 1-nonene with Carbopack B. Levels of straight-chain aldehyde artifacts rapidly diminished after a few cycles of adsorbent conditioning/O3 exposure, and concentrations could be predicted using a first-order model. Phenyl-substituted carbonyl artifacts (benzaldehyde and acetophenone) persisted on Tenax TA and GR even after 10 O3 exposure-conditioning cycles. O3 breakthrough through the adsorbent bed was most rapid in adsorbents that yielded the highest levels of artifacts. Overall, artifact composition and concentration are shown to depend on O3 concentration and dose, conditioning method, and adsorbent type and age. Calibrations showed good linearity, and most compounds had reasonable recoveries, for example, 90 +/- 15% for Tenax TA, 97 +/- 23% for Tenax GR, 101 +/- 24% for Carbopack B, and 79 +/- 25% (91 +/- 9% for n-aldehydes) for Carbopack X. Benzeneacetaldehyde recovery was notably poorer (22-63% across the four adsorbents). MDLs for several compounds were relatively high, up to 5 ng. By accounting for both artifact formation and method performance, this work helps to identify which carbonyl compounds can be measured using thermally desorbable adsorbents and which may be prone to bias because of the formation of O3-adsorbent artifacts.     

翡翠贻贝内脏团抗氧化酶活性及脂质过氧化物含量对苯并(b)荧蒽胁迫的生物响应研究

为了研究苯并(b)荧蒽这一典型的多环芳烃化合物对水生生物的毒性效应,测定了不同浓度(2.0、10.0和50.0 μg· L-1)苯并(b)荧蒽胁迫15 d和清水释放10 d后翡翠贻贝(Perna viridis)内脏团组织中抗氧化酶(CAT、SOD和GPx)活性和MDA含量的变化.结果表明,2.0 μg· L-1浓度组...     

Multi-scales Analysis of Driving Forces on Land Use/Cover Change in China： Taking Farmland Returning to Forest or Grassland as a Case

Increasing populations are causing an increase in food demands, and the area of cultivated land expands every year. Inappropriate land transition from ecology to production results in the constant decline of the ecological security level and influences the regional sustainable development. Adjusting unreasonable land use mode and reconstructing natural land cover are important ways to maintain and improve the ecological environment. Also reclaiming farmland as areas for forests and grasslands （FRFG） is another way. Successful implementation of FRFG in China is the result of comprehensive effect of the multi-scales driving forces. This paper analyses the driving forces of FRFG in China on a national （country） -regional （province） - local （county） - household （farmer） level scale, and the results are： driving forces at the national scale include ecological and food security and the western development of China; at the regional scale, ecological and economic benefits become the main factors to influence the dimension of FRFG under the same policy. The driving forces can be divided into 6 types： industrial structure adjustment, water source protection, flood prevention, the Three-Gorge Project protection, reduction of the amount of sediment flowing into the Yellow River and wind erosion desertification prevention. The driving forces at the local scale can be divided into 12 types with developing leading industries, increasing farmers＇ income and improving agricultural production conditions as the main types; at the household scale, the national policy meeting farmers＇ demands and the optimization of individual interests are all driving forces.     

钢板焊接缺陷自身高度测量

介绍了端点衍射波的产生及其计算自身高度的原理,采用常规仪器及探头测量的方法及体会。     

超越增长的极限

无论是发达国家还是发展中国家。渴望增长似乎是不争的共识。前者要进一步增加本国国民的生活舒适度，而后者则致力于摆脱贫困，尽快过上体面的生活。但是，地球资源尤其是维持现代经济增长的石油、天然气等不可再生资源的供应能力、全球环境容量以及地球生态系统的服务功能却是有限的。随着世界经济规模的不断扩大，这种有限性日益明显。6月底，原油期货价格不可思议地攀升至超过143美元／桶的历史新高。尽管疲软的美元、地缘形势不稳、投机者的兴风作浪等有可能助推油价再攀新高，     

傣族传统民居技术更新的可持续性研究——以西双版纳城子寨的新民居更新为例

以往的民居改建、更新理论和原则或是从美学的角度出发，或是从功能的角度探讨问题，本文旨在可持续发展思想的指导下，在保留和继承部分民居传统技术的同时，融入现代技术的思想和方法，从技术角度实现对西双版纳城子寨傣族传统民居的积极保护与有序更新，走出技术适宜更新的可持续发展之路。     

二氧化碳灭火系统误喷事故分析及预防措施探讨

根据二氧化碳灭火系统在工程中的实际应用,系统分析灭火系统误喷事故原因,建立引起二氧化碳灭火系统误喷事故树。通过事故树计算各基本事件的结构重要度,确定基本事件对误喷事故产生的影响程度,最后为防止误喷事故发生制定了预防措施。     

国内外环境风险防范与应急管理体系发展对策研究

随着经济的迅速发展,中国环境污染事件的发生频率也逐步升高,但环境风险防范与应急管理工作仅初显轮廓,很多方面都存在着欠缺与不足.通过介绍美国、欧盟等国外成熟的环境风险防范与应急管理体系的组织构架及管理措施,总结发达国家管理体系的优势和共同特征,并对中国现行的环境风险防范与应急管理体系进行梳理,识别存在问题,从而有针对性的借鉴、学习发达国家管理经验,为中国今后环境风险防范与应急管理体系的发展给出建议.     

A GIS‐ASSISTED DISTRIBUTED WATERSHED MODEL FOR SIMULATING FLOODING AND INUNDATION1

ABSTRACT: A distributed watershed model combining kinematic wave routing, 1‐D dynamic channel‐flow routing, and 2‐D diffusive overland‐flow routing has been developed to simulate flooding and inundation levels of large watersheds. The study watershed was linked to a GIS database and was divided into an upstream mountainous area and a downstream alluvial plain. A kinematic wave routing was adopted at the mountainous area to compute the discharge flowing into the alluvial plain. A 1‐D dynamic channel routing solving the St. Venant equations by the Preissmann method was performed for the main channel of the alluvial plain, whereas a 2‐D overland‐flow routing solving the diffusion wave equation with the Alternating Direction Explicit scheme was used for floodplains. The above two routings were connected by weir‐link discharge formula. The parameters in the model were calibrated and independently verified by single‐event storms. An example application of flooding/inundation analysis was conducted for the Taichung station and the Woozi depot (Taiwan High Speed Rail). Suggested inundation‐proofing measures ‐ including raising ground surface elevation of the station and depot and building a waterproofing exterior wall and their combination ‐ were investigated. It was concluded that building the waterproofing exterior wall had a strong tendency to decrease peak inundation depth.