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Raman spectroscopy of diesel and gasoline engine-out soot using different laser power
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作者 Haiwen Ge Zhipeng Ye Rui He 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第5期74-80,共7页
We studied engine-out soot samples collected from a heavy-duty direct-injection diesel engine and port-fuel injection gasoline spark-ignition engine. The two types of soot samples were characterized using Raman spectr... We studied engine-out soot samples collected from a heavy-duty direct-injection diesel engine and port-fuel injection gasoline spark-ignition engine. The two types of soot samples were characterized using Raman spectroscopy with different laser powers. A Matlab program using least-square-method with trust-region-reflective algorithm was developed for curve fitting. A DOE(design of experiments) method was used to avoid local convergence. The method was used for two-band fitting and three-band fitting. The fitting results were used to determine the intensity ratio of D(for 'Defect' or 'Disorder') and G(for'Graphite') Raman bands. It is found that high laser power may cause oxidation of soot sample, which gives higher D/G intensity ratio. Diesel soot has consistently higher amorphous/graphitic carbon ratio, and thus higher oxidation reactivity, compared to gasoline soot, which is reflected by the higher D/G intensity ratio in Raman spectra measured under the same laser power. 展开更多
关键词 Raman spectroscopy DIESEL ENGINE GASOLINE ENGINE SOOT emission PARTICULATE matter
滤膜浸泡时间对偏二甲肼中颗粒物测定的影响
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作者 吴翼 赵冰 +4 位作者 王莹 侯子文 齐敬 徐泽龙 徐世杰 《化学推进剂与高分子材料》 CAS 2019年第3期63-68,共6页
研究了偏二甲肼(UDMH)中颗粒物粒径的组成,测定了密理博滤膜浸泡过程中乙醇电导率的变化,分析了滤膜浸泡前后和过程中质量的变化,观察了滤膜的表面形貌,最后在未浸泡和正常浸泡滤膜间进行了对比实验。结果表明:UDMH中10μm以上颗粒物体... 研究了偏二甲肼(UDMH)中颗粒物粒径的组成,测定了密理博滤膜浸泡过程中乙醇电导率的变化,分析了滤膜浸泡前后和过程中质量的变化,观察了滤膜的表面形貌,最后在未浸泡和正常浸泡滤膜间进行了对比实验。结果表明:UDMH中10μm以上颗粒物体积占总体积的71.7%;滤膜离子含量不影响颗粒物元素测定,滤膜质量在浸泡后预计不变,滤膜表面质量良好;在正常浸泡和未浸泡滤膜所测定的颗粒物结果中,期望的差值为0.02mg/L,密理博滤膜可不浸泡直接用于实验。 展开更多
关键词 偏二甲肼 滤膜 颗粒物 密理博
Microbial aerosol chemistry characteristics in highly polluted air
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作者 Ting Zhang Xinyue Li +2 位作者 Minfei Wang Haoxuan Chen Maosheng Yao 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第8期1051-1063,共13页
Aerosol chemistry is often studied without considering microbial involvements. Here, we investigated time-and size-resolved bacterial aerosol dynamics in air. Under high particulate matter(PM) polluted episodes, bacte... Aerosol chemistry is often studied without considering microbial involvements. Here, we investigated time-and size-resolved bacterial aerosol dynamics in air. Under high particulate matter(PM) polluted episodes, bacterial aerosols exhibited a viability of up to 50%–70% in the 0.56–1 μm size range, at which elevated levels of SO42-, NO3- and NH4+ were concurrently observed.Engineered or acclimated for both industrial use, bacteria such as Psychrobacter spp., Massilia spp., Acinetobacter lwoffii,Exiguobacteriumaurantiacum and Bacillusmegaterium were shown to have experienced massive abundance shifts in polluted air on early mornings and late afternoons, on which rapid new particle formation events were widely reported. Here, Psychrobacter spp. were shown to account for >96% abundance at a corresponding PM2.5 level of 208 μg/m3. These observed bacterial aerosol changes corresponded to the PM2.5 mass peak shift from 3.2–5.6 μm to the high viability size range of 0.56–1 μm. Additionally,elevated levels of soluble Na, Ca, Mg, K, Al, Fe and P elements, required for bacterial growth, were observed to co-occur with those significant bacterial aerosol structure shifts in the air. For particular time-resolved PM2.5 pollution episodes, Acinetobacter,Psychrobacter and Massilia were shown to alternate in dominating the time-resolved aerosol community structures. The results from a HYSPLIT trajectory model simulation suggested that air mass transport played a minor role in affecting the observed bacterial aerosol structure dynamics. All the data here suggested that airborne bacteria in the size range of 0.56–1 μm could be extensively involved in aerosol chemistry in highly polluted humid air. 展开更多
关键词 BACTERIAL AEROSOL dynamics in AIR PARTICULATE matter size-and TIME-RESOLVED BACTERIAL AEROSOL AEROSOL chemistry
机油和过量空气系数对GDI汽油机燃用甲醇汽油颗粒排放的影响 预览
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作者 刘成豪 曾东建 +3 位作者 左子农 汪建忠 李翔 王瑜 《车用发动机》 北大核心 2019年第3期81-87,共7页
利用1台缸内直喷增压汽油机,在97号汽油和甲醇汽油中掺混体积分数为2%和4%的机油,探究机油以及不同过量空气系数对发动机颗粒排放特性的影响。试验研究表明:随着燃料中甲醇比例的增大,排气颗粒数浓度、总数浓度、质量浓度和总质量浓度... 利用1台缸内直喷增压汽油机,在97号汽油和甲醇汽油中掺混体积分数为2%和4%的机油,探究机油以及不同过量空气系数对发动机颗粒排放特性的影响。试验研究表明:随着燃料中甲醇比例的增大,排气颗粒数浓度、总数浓度、质量浓度和总质量浓度均降低,机油消耗和过量空气系数对排放颗粒浓度的影响逐渐减弱;随着机油掺混体积分数的升高和过量空气系数的减小,排气颗粒浓度都明显上升;发动机的排气颗粒数浓度主要分布在核态区域,而质量浓度分布则不同,主要集中在积聚态和粗态区域。 展开更多
关键词 直喷式汽油机 甲醇 机油 颗粒
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Analysis of Causes of Haze Weather in Winter in Zhangzhou City 预览
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作者 Wang Hong Zheng Qiuping +1 位作者 Xie Zuxin Wu Jiancheng 《气象与环境研究:英文版》 CAS 2019年第3期11-17,共7页
From December 3 to 12,2017,Zhangzhou experienced a haze weather process lasting for 10 days.In this paper,based on surface meteorological observation and environmental monitoring data,statistical comparison,Eta correl... From December 3 to 12,2017,Zhangzhou experienced a haze weather process lasting for 10 days.In this paper,based on surface meteorological observation and environmental monitoring data,statistical comparison,Eta correlation coefficient,clustering analysis and other methods were adopted to analyze the causes of haze weather in the whole process from clean air (December 2) to haze generation,maintenance (December 3-12) and dissipation (December 13).The results showed that two blasts of strong cold air invaded the city during the haze formation and maintenance,and regional pollution transport and static and stable weather were the main reasons for the continuous high concentration of particulate matter,the occurrence of mild pollution from PM 10 and PM 2.5 in some periods and mild-heavy haze weather lasting for 10 days.In this process,PM concentration had a strong negative correlation with air temperature and visibility,and the absolute values of the correlation coefficients were between 0.6 and 0.8.PM concentration correlated with relative humidity positively and with wind speed weakly.Regional transport of particulate matter and ozone was conducted in the form of northeast wind and southeast wind backflow.At night and in the morning,under the influence of static and stable weather and long-term sea and land breeze (6 d),average wind speed was less than 1.5 m/s,and the frequency of static wind and small wind exceeded 50%,while there was no precipitation.At 08:00,in the middle and low altitudes,the inversion layer appeared in one week,and cloud cover was large,while the height of mixed layer was below 600 m.In the whole process,it was in the weak divergence field under cold high pressure,and the overall diffusion,dilution and cleaning ability of the atmosphere were poor. 展开更多
关键词 PARTICULATE MATTER HAZE WEATHER CAUSE Zhangzhou
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Potential factors and mechanism of particulate matters explosive increase induced by free radicals oxidation
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作者 Guoying Wang Shiming Jia +11 位作者 Xiuli Niu Haoqi Tian Yanrong Liu Zhong Xie Chao Liu Yucan Dong Ying Su Jianglei Yu Gaofeng Shi Xuefu Chen Lan Li Peng Zhang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第7期205-213,共9页
Atmospheric particulate pollution in China has attracted much public attention.Occasionally, the particle number concentration increases sharply in a short time period,which is defined as a 'particulate matter exp... Atmospheric particulate pollution in China has attracted much public attention.Occasionally, the particle number concentration increases sharply in a short time period,which is defined as a 'particulate matter explosive increase'. Heavy particulate matter pollution not only reduces visibility but also has an adverse effect on human health. Hence,there is an urgent need to discover the causes of particulate matter explosive increase.During this campaign, the particle number concentration and free radicals were measured at a tall building on the campus of Lanzhou University of Technology. Additionally, we examined a series of chemicals to reproduce the observed particulate matter explosive increase in a smog chamber to determine its potential factors. Then, we analyzed the mechanism of particulate matter explosive increase in the presence of free radicals. We found that, among the potential inorganic and organic sources analyzed, a mixture of organic and SO2 in the research region had a major effect on particulate matter explosive increase. Moreover, free radical oxidation has a large effect, especially in the formation of organic particulates. 展开更多
关键词 PARTICULATE MATTER pollution Particle number concentration EXPLOSIVE INCREASE Free RADICAL OXIDATION
The origin of the suspended particulate matter in the seagrass meadow of tropical waters, an evidence of the stable isotope signatures 预览
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作者 Aan Johan Wahyudi Afdal 《海洋学报:英文版》 SCIE CAS CSCD 2019年第1期136-143,共8页
Suspended particulate matter (SPM) has been known as an important variable in the organic matter flow of coastal ecosystem. Half of burial carbon in seagrass meadows is contributed by allochthonous sources that compos... Suspended particulate matter (SPM) has been known as an important variable in the organic matter flow of coastal ecosystem. Half of burial carbon in seagrass meadows is contributed by allochthonous sources that compose the SPM such as phytoplankton, seagrass detritus, marine snow aggregates and terrestrially derived particles. Each composition of the SPM contributes different roles and is important to be identified, for instance, the exact contribution of seagrass detritus will be useful for determination of carbon export through the detritus form in seagrass meadows. Here, the SPM of seagrass meadows is studied in Bintan Island and the Selayar Archipelago. The aim of this research is to determine the source origin of the SPM using a stable isotope signature. In order to fulfill this aim, the objectives are defined as:(1) to specify the stable isotope signature (δ13C and δ15N) of the SPM, and (2) to determine the proportional distribution of the SPM’s prospectus sources. The result shows that the possibility of the source origin of the SPM includes a seagrass fraction (Enhalus acoroides and Thalassia hemprichii), terrestrial C4 plant, macroalgae, and terrestrial C3 plant. The SPM lies between the marine- and terrigenous-end members. However, it seems that the SPM is more to be terrigenous-end and allochthonous. According to a Bayesian mixing model, the terrestrial C4 has the highest contribution of the SPM at all sites except Barugaia and Pasi Island in Selayar (i.e., the highest contribution of the SPM is from the detritus of E. acoroides). The second contribution has been contributed by either seagrass detritus (E. acoroides or Th. hemprichii) or terrestrial C3 plant. The finding of this study indicates that there is a strong influence of the terrigenous sources in the SPM of the seagrass meadows. 展开更多
关键词 suspended particulate matter stable isotope source ORIGIN SEAGRASS ECOSYSTEMS
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Properties of coarse particles in suspended particulate matter of the North Yellow Sea during summer 预览
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作者 ZHANG Kainan WANG Zhenyan +1 位作者 LI Wenjian YAN Jun 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第1期79-92,共14页
Fine particles in seawater commonly form large porous aggregates.Aggregate density and settling velocity determine the behavior of this suspended particulate matter(SPM)within the water column.However,few studies of a... Fine particles in seawater commonly form large porous aggregates.Aggregate density and settling velocity determine the behavior of this suspended particulate matter(SPM)within the water column.However,few studies of aggregate particles over a continental shelf have been undertaken.In our case study,properties of aggregate particles,including size and composition,over the continental shelf of the North Yellow Sea were investigated.During a scientifi c cruise in July 2016,in situ eff ective particle size distributions of SPM at 10 stations were measured,while temperature and turbidity measurements and samples of water were obtained from surface,middle,and bottom layers.Dispersed and inorganic particle size distributions were determined in the laboratory.The in situ SPM was divided into(1)small particles(<32μm),(2)medium particles(32–256μm)and(3)large particles( >256μm).Large particles and medium particles dominated the total volume concentrations(VCs)of in situ SPM.After dispersion,the VCs of medium particles decreased to low values(<0.1μL/L).The VCs of large particles in the surface and middle layers also decreased markedly,although they had higher peak values(0.1–1μL/L).This suggests that almost all in situ medium particles and some large particles were aggregated,while other large particles were single particles.Correlation analysis showed that primary particles<32μm infl uenced the formation of these aggregates.Microscopic examination revealed that these aggregates consisted of both organic and inorganic fi ne particles,while large particles were mucus-bound organic aggregates or individual plankton.The vertical distribution of coarser particles was clearly related to water stratifi cation.Generally,medium aggregate particles were dominant in SPM of the bottom layer.A thermocline blocked resuspension of fi ne material into upper layers,yielding low VCs of medium-sized aggregate particles in the surface layer.Abundant large biogenic particles were present in both surface and middle layers. 展开更多
关键词 suspended PARTICULATE matter(SPM) coarse particles aggregates North Yellow Sea laser in SITU SCATTERING and transmissometery(LISST)
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Responses of Yellow Sea Cold Water Mass to Typhoon Bolaven 预览
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作者 LI Jianchao LI Guangxue +4 位作者 XU Jishang QIAO Lulu MA Yanyan DING Dong LIU Shidong 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第1期31-42,共12页
A two-month seabed-mounted observation(YSG1 area)was carried out in the western Yellow Sea Cold Water Mass(YSCWM)using an RDI-300K acoustic Doppler current profiler(ADCP)placed at a water depth of 38 m in late summer,... A two-month seabed-mounted observation(YSG1 area)was carried out in the western Yellow Sea Cold Water Mass(YSCWM)using an RDI-300K acoustic Doppler current profiler(ADCP)placed at a water depth of 38 m in late summer,2012.On August 2012,Typhoon Bolaven passed east of YSG1 with a maximum wind speed of 20ms^-1.The water depth,bottom temperature,and profile current velocities(including u,v and w components)were measured,and the results showed that the typhoon could induce horizontal current with speed greater than 70cms?1 in the water column,which is especially rare at below 20 meters above bottom(mab).The deepening velocity shear layer had an intense shear velocity of around 10cms?1m?1,which indicated the deepening of the upper mixed layer.In the upper water column(above 20mab),westward de-tide current with velocity greater than 30cms?1 was generated with the typhoon’s onshore surge,and the direction of current movement shifted to become southward.In the lower water column,a possible pattern of eastward compensation current and delayed typhoon-driven current was demonstrated.During the typhoon,bottom temperature variation was changed into diurnal pattern because of the combined influence of typhoon and tidal current.The passage of Bolaven greatly intensified local sediment resuspension in the bottom layer.In addition,low-density particles constituted the suspended particulate matter(SPM)around 10 mab,which may be transported from the central South Yellow Sea by the typhoon.Overall,the intensive external force of the Typhoon Bolaven did not completely destroy the local thermocline,and most re-suspended sediments during the typhoon were restricted within the YSCWM. 展开更多
关键词 YELLOW Sea Cold Water Mass TYPHOON typhoon-driven current THERMOCLINE suspended PARTICULATE MATTER
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Mechanisms of ultrafine particle formation during coal combustion in a new swirl modification device
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作者 Jun-xiang Guo Ling-ling Zhang +3 位作者 Wen-bin Dai Li-ying Qi Ru-fei Wei Da-qiang Cang 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第1期11-19,共9页
A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coa... A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coal.The distribution laws of different sized particulate matter(PM)emission and the enrichment laws of elements in particles under diverse conditions(such as various excess air coefficients and different coal ratios)were systematically studied.The enrichments of PM under both non-staged and fuel-staged conditions were also investigated.The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion,and a suitable coal ratio is also beneficial for reducing PM emissions.The melted liquid steel slag drop captured the fly ash produced from pulverized combustion,thus reducing PM emission.The alkali metal elements(K,Na,and Mg),the trace elements(As and Ti).and S have an obvious enrichment tendency in PM]and PM2.5,A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al,Si,Ca,and Fe in PM),whereas in PM2.5.PM4,and PM10,the effect of different coal ratios on the enrichment of each element is slight. 展开更多
关键词 Coal combustion Steel slag MODIFICATION PARTICULATE matter Elemernal enrichment Fuel-staged FEED Non-staged FEED SWIRL MODIFICATION DEVICE
Effects of the ambient fine particulate matter(PM2.5) exposure on urinary metabolic profiles in rats using UPLC-Q-TOF-MS
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作者 Lin Zhang Tengfei Xu +3 位作者 Zifeng Pi Meizhu Zheng Fengrui Song Zhiqiang Liu 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第1期90-94,共5页
In order to study the damage of ambient fine particulate matter(PM2.5) to organism in the environment,the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabo... In order to study the damage of ambient fine particulate matter(PM2.5) to organism in the environment,the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabolic pathways to clarify the toxicity mechanisms. Particles of PM2.5 collected from the fibrous membrane were extracted ultrasonically and dissolved in physiological saline to prepare PM2.5 suspension. The solution of saline and fine particular matter was injected into the trachea of rats respectively. The rats were injected two times a week for four weeks. Samples of 24-h urine were collected at the 14 th day after the end of exposure, and the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used for the metabolomics detection. Principal component analysis(PCA) was used to investigate the global metabolomic alterations and a clear separation in the scatter diagram were observed. 17 potential endogenous metablites were identified from urinary samples in rats by UPLC-Q-TOF-MS. The primary metabolism pathways involved pentose and glucuronate interconversions, starch and sucrose metabolism, tryptophan metabolism, tyrosine metabolism, phenylalanine metabolism, purine metabolism, acetaminophen metabolism pathway, retinol metabolism and valproic acid metabolism pathway.The results are helpful to understand the toxicological mechanisms of PM2.5 and screened out potential biomarkers of rats which exposure to PM2.5. 展开更多
关键词 AMBIENT fine PARTICULATE MATTER UPLC -Q-TOF-MS Metabolomics URINE
Emission factors of particulate matter, CO and CO2 in the pyrolytic processing of typical electronic wastes
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作者 Liyuan Chen Chuanyang Cai +3 位作者 Shuangyu Yu Yu Liu Shu Tao Wenxin Liu 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第7期93-101,共9页
A self-designed experimental device was employed to simulate the pyrolytic dismantling process of selected electronic wastes(E-wastes), including printed wiring boards(PWBs)and plastic casings. The generated particula... A self-designed experimental device was employed to simulate the pyrolytic dismantling process of selected electronic wastes(E-wastes), including printed wiring boards(PWBs)and plastic casings. The generated particulate matter(PM) of different particle sizes, carbon monoxide(CO) and carbon dioxide(CO2) were determined, and the corresponding emission factors(EFs) were estimated. Finer particles with particle sizes of 0.4–2.1 μm accounted for78.9% and 89.3% of PM emitted by the pyrolytic processing of PWBs and plastic casings,respectively, and the corresponding EFs were 9.68 ± 4.81 and 18.49 ± 7.2 g/kg, respectively.The EFs of CO and CO2 from PWBs and plastic casings were 55.9 ± 26.9 and 1182 ± 439 g/kg,and 133.6 ± 34.6 and 2827 ± 276 g/kg, respectively. Compared with other emission sources,such as coal, biomass, and traffic exhaust, the EFs of E-wastes were relatively higher,especially for PM. There were significant positive correlations(p < 0.05) of the initial contents of carbon and nitrogen in PWBs with the related EFs of PM, CO, and CO2, while the correlations for plastic casings were insignificant. The EFs of CO of PWBs were significantly positively correlated with the corresponding EFs of PM and the parent polycyclic aromatic hydrocarbons(PAHs);however, the same result was not observed for plastic casings. 展开更多
关键词 Pyrolytic processing of electronic-wastes PARTICULATE matter CO CO2 Emission factor
The Impact of Meteorological Factors on the Short-term Cumulative Effect of Air Particulate in Tianjin 预览
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作者 Wang Wei Liu Lili Wang Yan 《气象与环境研究:英文版》 CAS 2019年第2期27-32,40共7页
In order to reveal the rapid increase mechanism of particulate concentration in short time,a notion of short-term cumulative effect of air particulate is defined as the significant increase of pollutant concentration ... In order to reveal the rapid increase mechanism of particulate concentration in short time,a notion of short-term cumulative effect of air particulate is defined as the significant increase of pollutant concentration in a short time under the condition of breeze,stable weather and constant emission caused by human being’s activities. Subsequently,an index of short-term cumulative effect is established with air diffusive equation,and then the macro-scale meteorological situation and micro-scale factors of forming the short-term cumulative effect are discussed with the observation data. The macro-scale meteorological variables contain upper-level weather situations and surface weather situations. The micro-scale factors mainly include the boundary-layer height and boundary-layer stability. The analyses show that boundary-layer factors and weather variables have a significant influence on the short-term cumulative effect. The notion of short-term cumulative effect will play an important role in interpreting the severe pollution weather. 展开更多
关键词 AIR PARTICULATE SHORT-TERM CUMULATIVE Effect METEOROLOGICAL factor CUMULATIVE index
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基于NEDC循环的增压直喷汽油机颗粒物排放控制 预览
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作者 张毅 李基凤 +2 位作者 马冠钦 杨万里 王瑞平 《小型内燃机与车辆技术》 2019年第1期67-73,共7页
为了研究涡轮增压缸内直喷汽油机(TGDI)匹配整车在NEDC循环时颗粒物排放特性,以一款1.5L TGDI发动机为研究对象,在发动机台架上运行车辆NEDC循环对应的发动机工况来测试初始PM(Particulate Matter)与PN(Particulate Number)。该发动机初... 为了研究涡轮增压缸内直喷汽油机(TGDI)匹配整车在NEDC循环时颗粒物排放特性,以一款1.5L TGDI发动机为研究对象,在发动机台架上运行车辆NEDC循环对应的发动机工况来测试初始PM(Particulate Matter)与PN(Particulate Number)。该发动机初始PM为10 mg/km,PN为12×1013。PM排放不满足欧五,PN排放不满足欧六B,PM与PN排放均不满足开发目标。通过燃油二次喷射,优化二次喷射点火角,优化启动阶段空燃比,优化三元催化器加热时间与油轨压力,最终使PM降为1 mg/km,PN降为2.5×1012,满足欧六B与开发目标。研究表明:汽油二次喷射可以降低50%的颗粒物排放;三元催化器加热时间由60 s增加至80 s,可以降低10%的PN排放;PN与PM随着轨压压力的升高,先降低后升高,轨压压力0.8 MPa为最优方案。 展开更多
关键词 增压直喷汽油机 颗粒物 二次喷射 点火角
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Influence of gaseous and particulate species on neutralization processes of polar aerosol and snow — A case study from Ny-Alesund
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作者 Roseline C.Thakur Meloth Thamban 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期12-25,共14页
The inter-conversion of nitrogen and sulfur species between the gas and particulate phases and their interaction with alkaline species influences the acidity of the aerosols and surface snow. To better understand thes... The inter-conversion of nitrogen and sulfur species between the gas and particulate phases and their interaction with alkaline species influences the acidity of the aerosols and surface snow. To better understand these processes, a short field campaign was undertaken in Ny-Alesund, Svalbard, during 13th April 2012 to 24th April 2012. Air measurements were carried out through a particulate sampler equipped with denuders and filter packs for simultaneous collection of trace gases (HNO3, NO2, SO2 and reactive nitrogen compounds) and aerosols, with daily collection of snow samples. Ionic composition of the samples was analyzed using ion chromatography technique. The results suggested that nitrate-rich aerosols are formed when PAN (peroxy acetyl nitrate) disassociates to form NO2 and HNO3 which further hydrolyzes to form pNO3^- (particulate nitrate). This resulted in a high contribution of pNO3^- (62%) to the total nitrogen budget over the study area. The acidity of the aerosols and snow evaluated through cation/anion ratio (C/A) indicated alkaline conditions with C/A > 2. The bicarbonates/carbonates of Mg^2+ played an important role in neutralization processes of surface snow while the role of NH3 was dominant in aerosol neutralization processes. Such neutralization processes can increase the aerosol hygroscopicity causing warming. Chloride depletion in the snow was significant as compared to the aerosols, indicating two important processes, scavenging of coarse sea salt by the snow and gaseous adsorption of SO2 on the snow surface. However, a more systematic and long term study is required for a better understanding of the neutralization processes and chemical inter-conversions. 展开更多
关键词 PARTICULATE AEROSOL SCAVENGING NEUTRALIZATION ARCTIC
Machine learning to relate PM2.5 and PM10 concentrations to outpatient visits for upper respiratory tract infections in Taiwan:A nationwide analysis 预览
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作者 Mei-Juan Chen Pei-Hsuan Yang +4 位作者 Mi-Tren Hsieh Chia-Hung Yeh Chih-Hsiang Huang Chieh-Ming Yang Gen-Min Lin 《世界临床病例杂志》 2018年第8期200-206,共7页
AIM To examine the accuracy of machine learning to relate particulate matter(PM)2.5 and PM10 concentrations to upper respiratory tract infections(URIs).METHODS Daily nationwide and regional outdoor PM2.5 and PM10 conc... AIM To examine the accuracy of machine learning to relate particulate matter(PM)2.5 and PM10 concentrations to upper respiratory tract infections(URIs).METHODS Daily nationwide and regional outdoor PM2.5 and PM10 concentrations collected over 30 consecutive days obtained from the Taiwan Environment Protection Administration were the inputs for machine learning,using multilayer perceptron(MLP),to relate to the subsequent one-week outpatient visits for URIs.The URI data were obtained from the Centers for Disease Control datasets in Taiwan between 2009 and 2016.The testing used the middle month dataset of each season(January,April,July and October),and the training used the other months’datasets.The weekly URI cases were classified by tertile as high,moderate,and low volumes.RESULTS Both PM concentrations and URI cases peak in winter and spring.In the nationwide data analysis,MLP machine learning can accurately relate the URI volumes of the elderly(89.05%and 88.32%,respectively)and the overall population(81.75%and 83.21%,respectively)with the PM2.5 and PM10 concentrations.In the regional data analyses,greater accuracy is found for PM2.5 than for PM10 for the elderly,particularly in the Central region(78.10%and 74.45%,respectively),whereas greater accuracy is found for PM10 than for PM2.5 for the overall population,particularly in the Northern region(73.19%and 63.04%,respectively).CONCLUSION Short-term PM2.5 and PM10 concentrations were accurately related to the subsequent occurrence of URIs by using machine learning.Our findings suggested that the effects of PM2.5 and PM10 on URI may differ by age,and the mechanism needs further evaluation. 展开更多
关键词 PARTICULATE MATTER 2.5 PARTICULATE MATTER 10 Upper RESPIRATORY INFECTIONS Machine learning Air pollution
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添加乙醇燃料对汽油机起动过程微粒排放的影响 预览
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作者 袁超 洪伟 +2 位作者 苏岩 解方喜 陈静 《汽车工程》 CSCD 北大核心 2018年第12期1393-1397,1425共6页
为研究乙醇燃料的添加对直喷汽油机起动过程中微粒排放的影响,通过在汽油中添加体积百分比为10%和20%的乙醇得到E10和E20燃料,采用这两种燃料和汽油燃料对直喷汽油机起动过程的微粒排放进行了研究。结果表明:在起动前10s初始阶段,不论... 为研究乙醇燃料的添加对直喷汽油机起动过程中微粒排放的影响,通过在汽油中添加体积百分比为10%和20%的乙醇得到E10和E20燃料,采用这两种燃料和汽油燃料对直喷汽油机起动过程的微粒排放进行了研究。结果表明:在起动前10s初始阶段,不论燃用哪一种燃料,排气中微粒数量浓度都会急剧增加,是核态和积聚态两种形态微粒共同作用的结果,而起动过程中微粒数量浓度排放始终以核态为主;随着冷却液温度升高,积聚态微粒数量会大幅度降低;汽油中添加一定数量的乙醇,可以改善在起动工况下的核态微粒排放;燃用E20燃料在20和80℃条件下起动40s内微粒数量总浓度分别降低了37.8%和64.5%。 展开更多
关键词 直喷汽油机 乙醇 微粒 起动 排放
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颗粒物污染对高血压门急诊就诊人数的影响-时间序列研究 预览 被引量:2
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作者 翁俊 韦性富 +7 位作者 聂永红 王敏珍 康峰 孟祥燕 胡晓斌 裴泓波 白亚娜 郑山 《中国环境科学》 CSSCI CSCD 北大核心 2018年第7期2751-2757,共7页
为探讨颗粒物对金昌市高血压门急诊就诊人数影响的暴露反应关系,本文收集甘肃省金昌市2012年1月1日~2015年12月31日大气PM10、SO2、NO2数据及2014年1月1日~2015年12月31日大气PM2.5污染物监测数据及同期气象观测数据,同时收集近年金昌... 为探讨颗粒物对金昌市高血压门急诊就诊人数影响的暴露反应关系,本文收集甘肃省金昌市2012年1月1日~2015年12月31日大气PM10、SO2、NO2数据及2014年1月1日~2015年12月31日大气PM2.5污染物监测数据及同期气象观测数据,同时收集近年金昌市三家综合医院的高血压门急诊日就诊病例.采用广义相加模型,分析不同大气污染物与高血压门急诊日就诊人数的关联性.结果表明,在单污染物模型中,滞后L07d时PM10平均浓度每升高一个IQR,高血压日门急诊人数增加2.30%(95%CI:1.30%~3.32%),L6d时PM2.5平均浓度每升高一个IQR,高血压日门急诊人数增加2.53%(95%CI:1.45%~3.62%).PM10和PM2.5对男性、65岁以上高血压患者门急诊影响更高.SO2和NO2与颗粒物之间存在协同效应,沙尘天气下PM10对高血压门急诊人数的影响由2.30%增加到2.36%,PM2.5的影响由2.53%减少到2.39%.研究得出颗粒物污染对金昌市高血压门急诊就诊人数具有不同程度的影响,其中细颗粒物(PM2.5)的效应更强. 展开更多
关键词 颗粒物 高血压 门急诊人数 广义相加模型
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旱雨季岩溶地表河不同河段正构烷烃相态组成变化和来源解析
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作者 刘宁坤 孙玉川 +5 位作者 刘跃 刘九缠 乔依娜 吕现福 蒲敏 王赛男 《环境科学学报》 CSCD 北大核心 2018年第12期4728-4736,共9页
岩溶作用产生的无机碳可以在水生植物、微生物等作用下形成有机质,转化为较稳定的内源有机碳,这为寻找全球遗漏碳汇提供了新的突破口,而加强对岩溶区有机质的溯源研究是重要手段.为探究金佛山岩溶地表河溶解态、颗粒态和沉积物正构烷烃... 岩溶作用产生的无机碳可以在水生植物、微生物等作用下形成有机质,转化为较稳定的内源有机碳,这为寻找全球遗漏碳汇提供了新的突破口,而加强对岩溶区有机质的溯源研究是重要手段.为探究金佛山岩溶地表河溶解态、颗粒态和沉积物正构烷烃的含量、组分及来源,于2017年3月20日、9月26日分别在石钟溪上、中、下游进行采样,并利用气相色谱。质谱联用仪(GC—MS)对三相态正构烷烃的组分进行定量分析.结果显示。旱季溶解态、颗粒态和沉积物正构烷烃的平均含量分别为737ng·L^-1、6108ng·L^-1和7149ng·g^-1,雨季三者的平均含量分别为7129ng·L^-1、8146ng·L^-1和6213ng·g^-1.正构烷烃的含量整体表现为雨季高于旱季,以溶解态正构烷烃表现得最为显著,这主要由外源高等植物输入增多所致.旱季上、下游正构烷烃含量差异明显,以沉积物正构烷烃表现得最为显著,自上而下整体保持微升态势;雨季外源输入量较大,差异性减弱,整体变幅较小.不同季节降雨和气温的变化导致水动力条件、浊度及水温的不同,深刻地影响着不同相态和不同河段正构烷烃的来源和迁移.整体上,随着海拔降低,高等植物贡献度降低,水生植物和低等生物贡献度增高.当水动力条件较弱和浊度较低时,造成内源溶解有机质增多.同时会出现溶解态至颗粒态乃至沉积物的缓慢沉降迁移. 展开更多
关键词 正构烷烃 溶解态 颗粒态 沉积物 岩溶地表河
广东建筑陶瓷行业颗粒物产排影响因子分析 预览
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作者 王静 张栖 《中国陶瓷工业》 CAS 2018年第6期27-30,共4页
对广东建筑陶瓷行业的废气治理情况进行了全口径调研,提出该行业所有工序的颗粒物产排影响因子,甄别出行业政策、燃料种类、工艺设备、环境管理、除尘工艺等特征影响因子进行详细系统分析,并提出应对措施。
关键词 建筑陶瓷 颗粒物 产排 影响因子
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