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481.
采用电称冲击低压系统(ELPI)将无烟室和吸烟室内的空气颗粒物(0.03~10.00 μm)分成12级,对其粒子数和质量浓度进行测定.结果表明,吸烟室PM0.03~10.00的日平均粒子数和质量浓度分别是无烟室的1.50、1.13倍.烟草烟雾对室内颗粒物粒子数的影响集中在0.03~1.00 μm粒径段;对室内颗粒物质量浓度的影响表现为双模态结构,峰值分别在0.20~0.70、5.00~8.20 μm粒径段.烟草烟雾颗粒物的粒子数和质量浓度随烟雾消散时间的增加而减少,粒径越小,减小的越明显;烟草烟雾颗粒物在室内消散缓慢,会在长时间内造成影响,应引起足够关注. 相似文献
482.
Juan G. Navea Shihe Xu Charles O. Stanier Mark A. Young Vicki H. Grassian 《Atmospheric environment (Oxford, England : 1994)》2009,43(26):4060-4069
We have carried out kinetic studies to characterize the heterogeneous decay of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in the presence of representative mineral dust aerosol in order to obtain a better understanding of the atmospheric fate of these siloxanes. The heterogeneous chemistry of D4 and D5 with various mineral dusts was studied in an environmental aerosol reaction chamber using FTIR absorption spectroscopy to monitor the reaction. The apparent heterogeneous uptake coefficient, γapp, for D4 and D5 with various mineral dusts was measured under dry conditions and as a function of relative humidity (RH). In addition, the effect of initial D4 and D5 concentration on the rate and yield of the reaction was examined. The uptake coefficient, γapp, for D4 and D5 was similar for the most reactive aerosols tested, with kaolinite ≈hematite > silica. Limited uptake onto carbon black and calcite surfaces was observed for either siloxane. Reaction with hematite and kaolinite resulted in multilayer coverages, suggesting extensive polymerization of D4 and D5 on the aerosol surface. 相似文献
483.
Chongguo Tian Jianmin Ma Liyan Liu Hongliang Jia Diandou Xu Yi-Fan Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(25):3891-3901
Using a dynamic numerical atmospheric transport model for organochlorine pesticides (OCPs), the relationship between the East Asian summer monsoon and the fate of α-hexachlorocyclohexane (α-HCH), a banned OCP, in the atmosphere over Northeast Asia was investigated and assessed. The modeled temporal and spatial patterns and variability of α-HCH air concentrations during the summer months of 2005 revealed a strong link between this chemical in the atmosphere over Northeast Asia and the East Asian summer monsoon. At lower atmospheric levels, easterly and southeasterly winds blowing from relatively cold ocean surface convey α-HCH air concentration from southeast China to northeast China. A monsoon front extending from southeast China to Japan, characterized by a strong wind convergence, carried the air concentration to a high elevation of the atmosphere where it was delivered by southerly monsoon flow to northern China and North Pacific Ocean. This summer monsoon associated northward atmospheric transport caused a reversal of the soil/air exchange from outgassing to net deposition during spring–summer period. The modeled wet deposition fluxes of α-HCH agreed well with the changes in the typical summer monsoon rain bands, designated as Meiyu in China, Changma in Korea, and Baiu in Japan. The major wet deposition flux paralleled with the monsoon front as well as the monsoon rain bands. The temporal change in the fluxes exhibits abrupt northward advances, which is associated with a stepwise northward and northeastward advance of the East Asian summer monsoon. The modeled α-HCH outflow in the atmosphere from China occurs mostly in the summer months and through northeast China, featured strongly by the evolution of the summer month. This study suggests that the East Asian summer monsoon provides a major atmospheric pathway and summer outflows to α-HCH over East Asia. 相似文献
484.
Jun-Ji Cao Bai-Qing Xu Jian-Qiao He Xian-Qin Liu Yong-Ming Han Ge-hui Wang Chong-shu Zhu 《Atmospheric environment (Oxford, England : 1994)》2009,43(29):4444-4452
Carbonaceous aerosol concentrations were determined for total suspended particle samples collected from Muztagh Ata Mountain in western China from December 2003 to February 2006. Elemental carbon (EC) varied from 0.004 to 0.174 μg m?3 (average = 0.055 μg m?3) while organic carbon (OC) ranged from 0.12 to 2.17 μg m?3 and carbonate carbon (CC) from below detection to 3.57 μg m?3. Overall, EC was the least abundant fraction of carbonaceous species, and the EC concentrations approached those in some remote polar areas, possibly representing a regional background. Low EC and OC concentrations occurred in winter and spring while high CC in spring and summer was presumably due to dust from the Taklimakan desert, China. OC/EC ratios averaged 10.0, and strong correlations between OC and EC in spring–winter suggest their cycles are coupled, but lower correlations in summer–autumn suggest influences from biogenic OC emissions and secondary OC formation. Trajectory analyses indicate that air transported from outside of China brings ~0.05 μg m?3 EC, ~0.42 μg m?3 OC, and ~0.10 μg m?3 CC to the site, with higher levels coming from inside China. The observed EC was within the range of loadings estimated from a glacial ice core, and implications of EC-induced warming for regional climate and glacial ice dynamics are discussed. 相似文献
485.
污泥膨胀状态下原生动物群落结构分析 总被引:5,自引:0,他引:5
系统研究了丝状菌膨胀与非丝状菌膨胀2种典型污泥状态下原生动物的群落结构特征及其演变规律。伴随丝状菌的大量增殖,原生动物总量相应减少,匍匐型纤毛虫及有壳类肉足虫数量迅速上升,占据明显的优势地位,典型原生动物为斜管虫(Chilodonella sp.)、小轮毛虫(Trochilia minuta)以及匣壳虫(Centropyxis sp.);非丝状菌污泥膨胀对原生动物总量及种群结构影响较小,伴随粘性菌胶团的大量出现,各功能类群的比例变化较小,但原生动物总量持续增加,其中菌食性纤毛虫呈线性增加,典型原生动物为钟虫(Vorticella sp.)。 相似文献
486.
487.
氧化亚铁硫杆菌浸出废弃线路板中铜的研究 总被引:6,自引:1,他引:5
对废弃线路板中的铜进行了细菌浸出、只有硫酸亚铁环境下的浸出及酸浸出实验,研究了不同条件对比浸出效果,研究结果表明,细菌浸出比只有硫酸亚铁存在的浸出和酸浸要快得多。研究了在线路板粉末浓度12、24、40、60和120 g/L下浸出速率的变化,结果表明, 在考察范围内,浸出速度随着加入的废弃线路板粉末浓度的升高而降低,当线路板粉末的浓度>60 g/L时,浸出速度维持在较低水平,选取24 g/L作为浸出的线路板粉末的浓度。分别在细菌培养0、24、48和72 h时加入线路板粉末24 g/L进行浸出实验,结果表明,细菌培养时间长,使得浸出过程进行得也更快。 相似文献
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