Thermal transport properties of solid solution ͑La x Gd 1−x ͒ 2 Zr 2 O 7 have been investigated for thermal barrier coatings ͑TBCs͒ application. The introduction of point defects was intended to provide extra phonon scattering, and much lower thermal conductivity for the solid solution has been obtained compared with La 2 Zr 2 O 7 and Gd 2 Zr 2 O 7 . The phonon mean free paths of the solid solution were estimated and discussed with respect to the point defect scattering effect. Young's modulus and heat capacity of the solid solution, which determine the mean velocity and the carried energy of the phonons, respectively, were measured and both showed suppression compared with the end materials, possibly due to the lattice relaxation aroused by point defects. A theoretical model, which contains no adjustable parameters, was present to accurately describe the thermal conductivities of the solid solution by taking account of the mass and strain field fluctuations induced by the point defects.

Abstract. Dust invasion is an important type of particle pollution in China. During 1 to 6 May in 2011, a dust event was observed in the Yangtze River Delta region (YRD). The highest PM10 (particles up to 10 μ in diameter) concentration reached over 1000 μg m−3 and the visibility was below 3 km. In this study, the Community Multi-scale Air Quality modeling system (CMAQ5.0) coupled with an in-line windblown dust model was used to simulate the formation, spatial and temporal characteristics of this dust event, and analyze its impacts. The threshold friction velocity for loose, fine-grained soil with low surface roughness in the dust model was revised based on Chinese data to improve the model performance. This dust storm broke out in Xinjiang and Mongolia during 28 to 30 April and arrived in the YRD region on 1 May. The transported dust particles contributed to the mean surface layer concentrations of PM10 in the YRD region 78.9% during 1 to 6 May with their impact weakening from north to south due to the removal of dust particles along the path. The dry deposition, wet deposition and total deposition of PM10 in the YRD reached 184.7 kt, 172.6 kt and 357.32 kt, respectively. The dust particles also had significant impacts on optical/radiative characteristics by absorption and scattering. In Shanghai, the largest perturbations of aerosol optical depth (AOD) and irradiance were about 0.8 DU and −130 W m−2, which could obviously influence the radiation balance in this region. The decrease of actinic fluxes impacts future photochemistry. In Shanghai, the negative effects on the NO2 and O3 photolysis could be −35% when dust particles arrived. The concentrations of O3 and OH were reduced by 1.5% and 3.1% in the whole of China, and by 9.4% and 12.1% in the YRD region, respectively. Such changes in O3 and OH levels can affect the future formation of secondary aerosols in the atmosphere by directly determining the oxidation rate of their precursors. The work of this manuscript is meaningful for understanding the dust emissions in China as well as for the application of CMAQ in Asia. It is also helpful for understanding the formation mechanism and impacts of dust pollution in the YRD.

CO2/Ca(OH)2 precipitation reaction was used to prepare CaCO3 nanoparticles in this work. As a fast reaction system, nice mixing and a fast mass transfer rate of CO2 are required to enhance supersaturation. To increase the mixing performance, a microstructure reactor, a membrane dispersion minireactor, which has microfiltration membranes as the dispersion media, was introduced and CaCO3 nanoparticles with average diameters ranging from 34.3 to 110 nm were prepared. Several operating conditions were investigated for the purpose of controlling the particle size. In addition, a deep analysis on the mass transfer flux density of CO2 was carried out and the particle size decreased with the increasing of the mass transfer flux density during the reaction. Compared with a membrane-free reactor, it was found that the mixing performance was significantly enhanced by the effect of the micropore membrane, and nanoparticles cannot be prepared without it.