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Vertical distributions of air pollutants are crucial for understanding the key processes of atmospheric transport and for evaluating chemical transport models. In this paper, we present measurements of non-methane hydrocarbons (NMHCs) and halocarbons obtained from an intensive aircraft study over northeast (NE) China in summer 2007. Most compounds exhibited a typical negative profile of decreasing mixing ratios with increasing altitude, although the gradients differed with different species. Three regional plumes with enhanced VOC mixing ratios were discerned and characterized. An aged plume transported from the northern part of the densely populated North China Plain (NCP; i.e. Beijing-Tianjin area) showed relatively higher levels of HCFC-22, 1,2-dichloroethane (1,2-DCE) and toluene. In comparison, the plume originating from Korea had higher abundances of CFC-12, tetrachloroethene (C2Cl4) and methyl chloride (CH3Cl), while regional air masses from NE China contained more abundant light alkanes. By comparing these results with the earlier PEM-West B (1994) and TRACE-P (2001) aircraft measurements, continuing declining trends were derived for methyl chloroform (CH3CCl3), tetrachloromethane (CCl4) and C2Cl4 over the greater China-northwestern Pacific region, indicating the accomplishment of China in reducing these compounds under the Montreal protocol. However, the study also provided evidence for the continuing emissions of several halocarbons in China in 2007, such as CFCs (mainly from materials in stock) and HCFCs. © 2011 Elsevier Ltd.

Abstract: A series of nano-Cr2−x Al x O3 (x =0–1) solid solution powders were prepared by sol–gel-chelating processing with citrate-dispersant method. The crystalline structure and size of the Cr2−x Al x O3 powders were determined by X-ray diffraction and transmission electron microscopy. It was demonstrated that the crystalline size of the Cr2−x Al x O3 powders decreases from 33nm to 13nm with an increase in the amount of Al2O3 substitution. The aluminum in the lattice of the Cr2−x Al x O3 can effectively prevent the crystalline growth of the Cr2−x Al x O3 powders during calcining at higher temperature. [Copyright &y& Elsevier]

Abstract: A series of single β-phase nano-Ag1−x Cu x I (x =0–0.5) solid solutions powders were synthesized by wet-chemical–chelating reaction processing and citric acid used as complexing agent. The Ag1−x Cu x I powders were determined by X-ray diffraction and transmission electron microscopy. It was demonstrated that the crystalline size and lattice parameter of the Ag1−x Cu x I powders decrease with an increase in the amount of CuI substitution. The copper in the lattice of the Ag1−x Cu x I can effectively prevent the crystalline growth of the Ag1−x Cu x I powders and citrate used in the Ag1−x Cu x I powders synthesized process can accelerate single β-phase crystalline structure formation. [Copyright &y& Elsevier]