Beijing University of Civil Engineering and Architecture is a university in Beijing, China. Established in 1936. It is maintained by the Beijing municipal government. Wikipedia.
Wang X.,Beijing University of Civil Engineering and Architecture |
Chi Y.,Northeast Forestry University |
Mu T.,Renmin University of China
Journal of Molecular Liquids | Year: 2014
Transport properties include the thermal conductivity for heat transfer, the viscosity for the momentum transfer, and the diffusion coefficient for mass transfer. The transport properties are very important for chemical engineering design. The ionic liquids are liquids with good conductivity thus may have promising applications in battery industry. However, the high viscosity hinders the applications of them. In this paper, we firstly reviewed the values of transport properties of pure ionic liquids, then these properties of the mixtures of ionic liquids with other compounds were discussed, and lastly we reviewed the correlation researches on the transport properties of systems including ionic liquids and the molecular dynamics simulation investigations on these systems. © 2014 Elsevier B.V. All rights reserved.
Yu X.,Beijing University of Civil Engineering and Architecture |
Shen Z.,Beihang University
Vacuum | Year: 2011
In the present study, TiO 2 films were deposited on the surface of cenosphere particles using the modified magnetron sputtering equipment under different working conditions. The resulting films were characterized by field emission scanning electron microscopy (FE-SEM), Atomic Force Microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The FE-SEM and AFM results show that the grain sizes and root-mean-square (RMS) roughness values of the TiO 2 films increase with the increase in deposition time and film thickness. The XRD results indicate that the film was TiO 2 film and sputtering time is an importance condition to influence the films crystal. With the increasing of sputtering time, the crystallization of the TiO 2 film was increased. The XPS results show that only TiO 2 films existed on the surface of cenosphere particles. In addition, the photocatalytic activities of these films were investigated by degrading methyl orange under UV irradiation. The results suggest that the photocatalytic activity of cenosphere particles with anatase TiO 2 films is remarkable and this catalyst can be applicable for the photocatalytic degradation of other organic compounds under UV lights. © 2011 Elsevier Ltd. All rights reserved.
Kong F.,Central South University |
Zhang Q.,Beijing University of Civil Engineering and Architecture
Energy and Buildings | Year: 2013
In cold severe area, the exterior layers of building envelope usually experience seasonal freezing/thawing in winter. However, it would lead to severe problems especially in the newly completed building. In order to analyze the drying of envelope on building initial use, the heat and moisture coupled transfer of building envelope in severe cold area Harbin, China was simulated. The modeled result was analyzed. It is concluded that the drying rate of the newly completed building envelope is significantly high in the first year, especially in the first few months. Insulation performance of the wall in the first winter is most serious due to the high initial moisture and freezing ice content in insulation layer. For the simulated envelope, the freezing of the moisture content especially that in insulation layer had notable effect on heat transfer coefficient (thermal resistance), and the maximum of modeled envelope heat transfer coefficient in the first year winter is about 7% higher than that in the tenth year, which is taken as final hygral state. Some parameters as apparent density, specific heat, average thermal diffusivity, heat storage coefficient and thermal inertia index, which were always considered as constants for a fixed building envelope are also changed with the heat and mass transfer of building envelope. © 2013 Elsevier B.V. All rights reserved.
Lin L.,Shanghai JiaoTong University |
Peng H.,Beijing University of Civil Engineering and Architecture |
Ding G.,Shanghai JiaoTong University
International Journal of Refrigeration | Year: 2016
As wetting behavior is a key factor affecting boiling heat transfer performance of refrigerant-oil mixture, the influence of oil concentration on wetting behavior during evaporation of refrigerant-oil mixture on copper surface was experimentally investigated. The wetting behavior was analyzed by capillary rise method, and the test conditions covered oil concentrations of 1, 3, 5 and 10 wt%, and surface roughness of 0.028, 0.079, 0.144, 0.419 and 1.166 μm. The experimental results show that protuberant liquid film occurs in front of meniscus during evaporation of refrigerant-oil mixture; and contact line velocity, contact angle, liquid film length and rising liquid height increase as oil concentration increases. It is also found that the ratio of the rising liquid height of refrigerant-oil mixture to that of pure refrigerant is larger than 1, and ranges between 1.42 and 2.18 under present test conditions, indicating that the presence of oil significantly enhances the surface wettability of refrigerant. © 2015 Elsevier Ltd and International Institute of Refrigeration.
Xing M.,Xian Jiaotong University |
Wang R.,Beijing University of Civil Engineering and Architecture |
Yu J.,Xian Jiaotong University
International Journal of Refrigeration | Year: 2014
In this work, the fullerene C60 nano-oil is proposed as a promising lubricant to enhance the performance of domestic refrigerator compressors. The stability of fullerene C60 nanoparticles dispersed in a mineral oil and the lubrication properties of the nano-oil were investigated experimentally. It was confirmed that the nanoparticles steadily suspend in the mineral oil at stationary conditions for a long period of time. The friction coefficients of the nano-oil significantly decrease with increasing the concentration of nanoparticles in the mineral oil, especially at the lower applied loads. The friction coefficients of the nano-oil with the concentration of 1-3 g L-1 are 12.9-19.6% lower than that of pure mineral oil. The applications of the nano-oil with the specific concentration of 3 g L -1 to two domestic refrigerator compressors were examined by compressor calorimeter experiments. The results shows the COPs of two compressors were improved by 5.6% and 5.3%, respectively, when the nano-oil was used instead of pure mineral oil. © 2014 Elsevier Ltd and IIR. All rights reserved.