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1.
室外空气污染和污染空气中的颗粒物是一类致癌物,而近年中国的大气颗粒物污染仍然维持在较高浓度水平。通过综述中国近年大气颗粒物污染现状和开展的颗粒物致癌机制研究,分析中国研究中颗粒物有关实验动物致癌性的证据和颗粒物致癌的人群流行病学线索,阐述大气颗粒物与癌症的关系,提出中国亟需开展相关研究。 相似文献
2.
考察了燃料添加剂对降低柴油机烟粒燃点温度的效应。含金属添加剂的柴油机烟粒被收集在金属纤维过滤器上,把原状烟粒样品移入实验室反应器,用模拟柴油机排气进行燃烧试验。实验结果表明,当烟粒中含有Pd或Cu时,烟粒的燃点温度可降至430℃左右(普通柴油机烟粒的燃点温度约600℃);Pd的添加还可大大降低烟粒一次燃烧产物中CO的分率。文中还对金属(催化剂)/烟粒接触程度和添加剂溶液中可燃性部分对烟粒燃烧的影响作了讨论。 相似文献
3.
E.M. Rabinovich D.W. Johnson Jr. A. Mishkevich E.A. Chandross J. Thomson Jr. 《Journal of Sol-Gel Science and Technology》2003,28(1):19-29
Particulate sol-gel technology uses larger particles than that of alkoxide-derived gels and provides larger pore sizes in the gelled object. This allows relatively rapid drying and fabrication of large rods or tubular shapes. However, the formation of more complex or flat shapes, which require extensive surface contact with a mold, is more difficult. The shrinkage during drying, with the significantly greater stress of surface friction due to adhesion, frequently leads to cracking.We have demonstrated a solution to this problem by floating the gel on the surface of a dense liquid. Dry silica panels up to 28 × 40 × 0.7 cm3 were prepared in this way. The use of patterning molds allowed the fabrication of more sophisticated shapes. These bodies were sintered to transparent vitreous silica articles of near net dimensions. 相似文献
4.
工业污染排放中气──固两相流的光学测量 总被引:1,自引:0,他引:1
烟尘及各种工业性粉尘排放是典型的气-固两相系.迄今为止,国内外尚缺少有效的监测其排放的手段.本文基于光的散时原理,提出了一种非接触的光学方法,能对上述固体颗粒物的污染排放浓度及粒径大小进行实时、在线的监测。计算机模拟和实验研究表明,该方法具有广阔的工业应用前景。 相似文献
5.
Carmen Moscoso-Pérez Purificación López-Mahía Soledad Muniategui-Lorenzo Esther Fernández-Fernández Darío Prada-Rodríguez 《Analytica chimica acta》2004,526(2):185-192
A highly sensitive and simple method, based on hydride generation and atomic fluorescence detection, has been developed for the determination of As, Bi, Sb, Se(IV) and Te(IV) in aqua regia extracts from atmospheric particulate matter samples. Atmospheric particulates matter was collected on glass fiber filters using a medium volume sampler (PM1 particulate matter). Two-level factorial designs have been used to optimise the hydride generation atomic fluorescence spectrometry (HG-AFS) procedure. The effects of several parameters affecting the hydride generation efficiency (hydrochloric acid, sodium tetrahydroborate and potassium iodide concentrations and flow rates) have been evaluated using a Plackett-Burman experimental design. In addition, parameters affecting the hydride measurement (delay, analysis and memory times) have been also investigated. The significant parameters obtained (sodium tetrahydroborate concentration, sodium tetrahydroborate flow rate and analysis time for As; hydrochloric acid concentration and sodium tetrahydroborate flow rate for Se(IV); and sodium tetrahydroborate concentration and sodium tetrahydroborate flow rate for Te(IV)) have been optimized by using 2n + star central composite design. Hydrochloric acid concentration and sodium tetrahydroborate flow rate were the significant parameters obtained for Sb and Bi determination, respectively. Using a univariate approach these parameters were optimized. The accuracy of methods have been verified by using several certified reference materials: SRM 1648 (urban particulate matter) and SRM 1649a (urban dust). Detection limits in the range of 6 × 10−3 to 0.2 ng m−3 have been achieved. The developed methods were applied to several atmospheric particulate matter samples corresponding to A Coruña city (NW Spain). 相似文献
6.
Summary A method is described for the determination of nitrated polynuclear aromatic hydrocarbons (nitro-PAHs), in particular 1-nitropyrene, in diesel particulate extracts. The method employs a multidimensional HPLC (column switching) technique with final on-line peak identification by UV-VIS spectral comparison with standards. To achieve exceptional chromatographic selectivity for nitro-PAHs, a new pyrene butyric acid amide phase has been prepared which is capable of forming donor-acceptor complexes with them. With this technique it is possible to confirm the presence of 1-nitropyrene in the range 3–100 ng/mg on filter-collected diesel soot. Its utility was demonstrated with diesel exhaust extracts spiked with varying levels of 1-nitropyrene and proved to be highly selective.Parts of this work have been presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984.Dedicated to Prof. J. F. K. Huber at the occasion of his 60th birthday. 相似文献
7.
王鲁 《北京理工大学学报》1998,18(4):401-405
研究金属-陶瓷功能梯主材料的基体与颗粒的界面热应力。方法给出功能制备的有限元计算优化设计方案,针对所制备的梯度材料的结构特点,采用双层嵌套模型研究基体与颗粒的界面热应力与两相材料体积分数的变化关系。 相似文献
8.
Alfredo Carrascull Claudia Grzona Daniela Lick Marta Ponzi Esther Ponzi 《Reaction Kinetics and Catalysis Letters》2002,75(1):63-68
The catalytic combustion of particulate material was studied on cobalt catalysts promoted with potassium using different supports for its preparation. Silica, aluminium oxides and hydroxides, zirconium oxide and hydroxide were used as supports. The catalytic activity for combustion depends on the type of support used, the higher activity corresponding to the supported catalyst on zirconium oxide. TPR studies indicate that the interaction metal/support allows to explain the higher activity of the CoK/SiO2 catalyst with respect to the CoK/Al2O3 but the high activity found in CoK/ZrO2is not explained by this interaction. In all cases the Co and K improved the performance of the catalysts. 相似文献
9.
Summary Using a two-step liquid chromatographic separation on normalphase cartridges, crude extracts of diesel particulate matter
can be separated without time-consuming sample handling into special fractions which mainly contain slightly-polar oxygenated
polycyclic aromatic hydrocarbons (oxy-PAH) and nitrated polycyclic aromatic hydrocarbons (nitro-PAH). Subsequent analysis
was by fused-silica capillary gas chromatography on a SE54 column along with flame-ionisation (GC/FID) and positive-ion electron-impact
mass spectrometric detection (GC/MS) respectively. A number of individual oxy-PAH belonging to four different chemical classes
(ketones, quinones, anhydrides and aldehydes) and several individual nitro-PAH were characterized by their retention times
and mass spectra.
Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984 相似文献
10.
Dabek-Zlotorzynska E Aranda-Rodriguez R Graham L 《Journal of separation science》2005,28(13):1520-1528
Urban fine airborne particulate matter (PM2.5) and vehicle emission samples were studied for water-soluble low-molecular-weight carboxylic acids using CE with indirect UV detection. Further identification of these acids was achieved using GC-MS as their butyl esters (after derivatization with BF3/butanol). Several dicarboxylic acids in the range C2-C10 including straight-chain, branched-chain, cis- and trans-unsaturated, and aromatic acids were confirmed by GC-MS. In addition, aromatic acids such as benzoate, phthalate, terephthalate, isophthalate, and 4-methylphtalate were present in such samples, but some of these were not well resolved by the used CE method. Oxocarboxylic acids (Cn(w) with n > 4) were also identified by GC-MS but not determined by CE due to lack of standards. The rapidity and simplicity of the CE method were clearly demonstrated, and the method was observed to be advantageous for routine monitoring of water-soluble organic acids in airborne PM2.5 and vehicle emission at low microg/L levels. 相似文献