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打印机的应用日趋广泛,其释放的颗粒物质尤其是纳米颗粒引起人们的高度关注。现有研究已经证明纳米级颗粒物更容易进入呼吸系统,穿越气血屏障,随之引起机体的氧化损伤、炎症反应和遗传毒性等。打印机释放颗粒的暴露水平评价及其毒理学效应识别是评估打印机健康风险的基础。本文综述了打印机工作场所颗粒暴露水平的监测结果、实验室模拟研究进展、人体采样评价、流行病学调查、体外细胞或整体动物水平毒理学效应评价方法及结果,并提出了打印机危害评估过程的标准化方案建议,以利于不同研究间的比较和总结。 相似文献
253.
为了解兰州银滩湿地公园对黄河水质的净化作用,对兰州银滩湿地公园不同河段的水流中氨氮、亚硝酸盐氮、总磷和氟化物的含量进行了测定。测定结果表明:湿地对水中TP的净化效果较好,去除率达到79.6%;对NH4+-N的净化效果次之,去除率达到了40.0%;对F-和NO2--N的净化作用一般。 相似文献
254.
Xianbao Shen Zhiliang Yao Qiang Zhang David Vance Wagner Hong Huo Yingzhi Zhang Bo Zheng Kebin He 《环境科学学报(英文版)》2015,27(5):209-220
A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China,NOx emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT (Computer Programmer to calculate Emissions from Road Transport) and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5 (Highway Vehicle Particulate Emission Modeling Software) models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent, which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-basedmodels will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models. 相似文献
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从"阳光体育"助推学校体育管理变革出发,借鉴和运用利益相关者理论,分析我国学校体育管理变革的逻辑基础以及划分出不同的利益相关者,指出学校体育管理变革实质上就是各利益相关者之间利益博弈或行为协作的制度变迁过程,其结果是各利益相关者对学校体育资源及其附属品的再分配,其中利益冲突是变革的核心内容,而造成利益冲突的原因是多方面的。走向利益均衡是学校体育管理变革的基本价值取向。 相似文献
257.
In this article, we hypothesize that in addition to participation status and household characteristics, the impact of China’s
Sloping Land Conversion Program on income growth and labor transfer is determined by local economic conditions, program range,
and political leadership, and the degree of impact on income may vary among different economic sectors. To test these propositions,
we have compiled a panel data set of 600 households in three counties in the Loess Plateau region, with observations for times
both prior to and after the program’s inception (1999 and 2006), for both aggregate and categorical incomes, and for both
participating and non-participating households. Using a difference in differences model and repeated cross-sectional data,
we find that participation status, local economic conditions, program extent, and political leadership indeed have significant
impacts on household income and off-farm employment. Moreover, the effects of participation on crop production income, animal
husbandry income, and off-farm income vary substantially. These results carry major policy implications in terms of how to
improve the effectiveness and impact of ecological restoration efforts in and outside of China. 相似文献
258.
Xiaowei Wang Beidou Xi Shouliang Huo Wenjun Sun Hongwei Pan Jingtian Zhang Yuqing Ren Hongliang Liu 《环境科学学报(英文版)》2013,25(7):1281-1290
Characterization, treatment and releases of eight polybrominated diphenyl ethers (PBDEs) congeners and sixteen polycyclic aromatic hydrocarbons (PAHs) in wastewater were evaluated along the treatment processes of a typical secondary treatment municipal sewage treatment plant (STP) (in Hefei City) situated the beside Nanfei River, East China. The findings showed that the average concentrations of the total PBDEs in raw wastewater and treated effluent were 188.578 and 36.884 ng/L respectively. Brominated diphenyl ether (BDE) 209 congener, the predominant PBDE in the STP and Nanfei River, could be related to the discharge of car-industry-derived wastes. For PAHs, the average concentrations in raw wastewater and treated effluent were 5758.8 and 2240.4 ng/L respectively, with naphthalene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene being detected at the highest concentrations. PAHs mainly originate from the combustion of biomass/coal and petroleum. The STP reduced about 80% of the PBDEs and 61% of the PAHs, which were eliminated mainly by sedimentation processes. The removal rates of PBDEs/PAHs increased with the increase of their solid-water partitioning coefficients. Accordingly, the STP's effluent, containing some PBDE congeners (e.g., BDE 47, 99 and 209, etc.) and low-molecular-weight PAHs, could be an important contributor of these contaminants' input to Nanfei River. It resulted in a significant increase of PBDE/PAH concentrations and PAH toxicological risk in the river water downstream. About 4.040 kg/yr of PBDEs and 245.324 kg/yr of PAHs could be released into the Nanfei River. The current conventional wastewater treatment processes should be improved to remove the relatively low-molecular-weight PBDEs/PAHs more effectively. 相似文献
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固相微萃取-气相色谱法联用测定水中氯苯系化合物 总被引:1,自引:0,他引:1
采用顶空固相微萃取与气相色谱联用技术对水中九种氯苯进行测定。优化了SPME的萃取条件,选用65μmPDMS—DVB萃取涂层,在加入1.5gNaCl,温度为20℃的条件下萃取15min,280%解吸4min。该方法的相对标准偏差小于8%,相关系数大于0.9988。将该方法应用于湘江水中氯苯的测定,回收率分别为79.4%-99.9%,证明了访方法对痕量氯苯分析的可行性与可靠性。 相似文献