A series of Si/C composites were fabricated based on pitch and Si powders with particle sizes of 30, 100, 500, and 3000 nm. The size effects of the Si particles in the Si/C composites were investigated for lithium-ion...A series of Si/C composites were fabricated based on pitch and Si powders with particle sizes of 30, 100, 500, and 3000 nm. The size effects of the Si particles in the Si/C composites were investigated for lithium-ion battery anodes. The nanoscale Si and Si/C composites exhibited good capacity retentions. Scanning electron microscopy showed that exterior and interior cracks emerging owing to volume expansion as well as parasitic reactions with the electrolyte could well explain the performance failure.展开更多
This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under di...This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under different drying temperatures and relative humidity are carried out in a constant climate chamber. Then, the undisturbed samples, prepared in different drying environment, are used for the triaxial tests and mercury intrusion tests. It is found that the drying environment has noticeable influence on the engineering properties of expansive soils and it can be characterized by the drying rate. The linear shrinkage and strength increase with the decrease of the drying rate. The non-uniform deformation tends to happen in the high drying rate, which subsequently furthers the development of cracks. In addition, during the drying process, the variation of pores mainly focuses on the inter-aggregate pores and inter-particle pores. The lower drying rate leads to larger variation of pore size distribution.展开更多
Expanded fluidization behavior in liquid-solid mini-fluidized beds （MFBs） was experimentally investigated using visual measurements. Wall effects in the liquid-solid MFBs were identified and explained. The measured ...Expanded fluidization behavior in liquid-solid mini-fluidized beds （MFBs） was experimentally investigated using visual measurements. Wall effects in the liquid-solid MFBs were identified and explained. The measured incipient]minimum fluidization liquid velocity （Umf） in the MFBs was 1.67 to 5.25 times higher than that calculated using the Ergun equation when the ratio of solid particle diameter to bed diameter varied from 0.017 to 0.091. The ratio of the Richardson-Zaki （R-Z） exponent obtained by fitting with experimental data to that calculated using the R-Z correlation varied from 0.92 to 0.55. A wider solid particle size distribution resulted in a smaller R-Z exponent. The influence of the solid particle material on Umf and R-Z exponent was negligible.展开更多
基金Project supported from the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09010102)
文摘A series of Si/C composites were fabricated based on pitch and Si powders with particle sizes of 30, 100, 500, and 3000 nm. The size effects of the Si particles in the Si/C composites were investigated for lithium-ion battery anodes. The nanoscale Si and Si/C composites exhibited good capacity retentions. Scanning electron microscopy showed that exterior and interior cracks emerging owing to volume expansion as well as parasitic reactions with the electrolyte could well explain the performance failure.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41430634)the State Key Laboratory of Geomechanics and Geotechnical Engineering (Grant No. Y11002)
文摘This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under different drying temperatures and relative humidity are carried out in a constant climate chamber. Then, the undisturbed samples, prepared in different drying environment, are used for the triaxial tests and mercury intrusion tests. It is found that the drying environment has noticeable influence on the engineering properties of expansive soils and it can be characterized by the drying rate. The linear shrinkage and strength increase with the decrease of the drying rate. The non-uniform deformation tends to happen in the high drying rate, which subsequently furthers the development of cracks. In addition, during the drying process, the variation of pores mainly focuses on the inter-aggregate pores and inter-particle pores. The lower drying rate leads to larger variation of pore size distribution.
文摘Expanded fluidization behavior in liquid-solid mini-fluidized beds （MFBs） was experimentally investigated using visual measurements. Wall effects in the liquid-solid MFBs were identified and explained. The measured incipient]minimum fluidization liquid velocity （Umf） in the MFBs was 1.67 to 5.25 times higher than that calculated using the Ergun equation when the ratio of solid particle diameter to bed diameter varied from 0.017 to 0.091. The ratio of the Richardson-Zaki （R-Z） exponent obtained by fitting with experimental data to that calculated using the R-Z correlation varied from 0.92 to 0.55. A wider solid particle size distribution resulted in a smaller R-Z exponent. The influence of the solid particle material on Umf and R-Z exponent was negligible.
