A rate model, which considers axial dispersion, external mass transfer, intraparticle diffusion and nonlinear isotherms, and ports periodic switching is adopted to simulate the simulated moving bed （SMB） process. Th...A rate model, which considers axial dispersion, external mass transfer, intraparticle diffusion and nonlinear isotherms, and ports periodic switching is adopted to simulate the simulated moving bed （SMB） process. The effects of flow rate in Sections 2 and 3 and switching time on the operating performance parameters： purity, recovery, productivity and dcsorbent consumption are studied. A simulation approach is applied to simulate the operation and performance of the SMB. The model predicts the performance of the transient and cyclic steady state behavior to a reasonably good extent, and provides guidance operation condition of the SMB process.展开更多
A simulated moving bed (SMB), equipped with eight silica-gel columns, was used to separate phosphatidylcholine (PC) from soybean phospholipids. The effects of flow rate in Sections 2 (Q2) and 3 (Q3), switching time, f...A simulated moving bed (SMB), equipped with eight silica-gel columns, was used to separate phosphatidylcholine (PC) from soybean phospholipids. The effects of flow rate in Sections 2 (Q2) and 3 (Q3), switching time, feed flow rate and feed concentration on the operating performance parameters: purity, recovery, productivity and desorbent consumption were studied. Operating conditions leading to more than 90% purity in both outlet streams have been identified, together with those achieving optimal performance. Regions leading to complete separation are observed and explained theoretically. As the mass-transfer effect was not considered, the triangle theory only gives initial guesses for the optimal operating conditions.展开更多
The objective of the present study was to determine the proper sources and concentrations of soybean lecithin （phosphatidylcholine, PC） to be used as substitute for hen egg yolk in extender for preserving goat semen...The objective of the present study was to determine the proper sources and concentrations of soybean lecithin （phosphatidylcholine, PC） to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin （20% and 95% soybean phosphatidylcholine; PC20 and PC95） and three concentrations （1%, 2% and 3% v/v） of PC20 and PC95 supplemented in Tris-citric acid-fructose （TCF） extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ （equilibration）. The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender （P 〈 0.05）. Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders （P 〈 0.05）. PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 （P 〈 0.05）. It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% （v/v） is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs .展开更多
基金Supported by the Doctoral Program Foundation of the Institution of Higher Education of China (No.20040335045).
文摘A rate model, which considers axial dispersion, external mass transfer, intraparticle diffusion and nonlinear isotherms, and ports periodic switching is adopted to simulate the simulated moving bed （SMB） process. The effects of flow rate in Sections 2 and 3 and switching time on the operating performance parameters： purity, recovery, productivity and dcsorbent consumption are studied. A simulation approach is applied to simulate the operation and performance of the SMB. The model predicts the performance of the transient and cyclic steady state behavior to a reasonably good extent, and provides guidance operation condition of the SMB process.
基金Project (No. 20040335045) supported by the Specialized ResearchFund for the Doctoral Program of Higher Education of China
文摘A simulated moving bed (SMB), equipped with eight silica-gel columns, was used to separate phosphatidylcholine (PC) from soybean phospholipids. The effects of flow rate in Sections 2 (Q2) and 3 (Q3), switching time, feed flow rate and feed concentration on the operating performance parameters: purity, recovery, productivity and desorbent consumption were studied. Operating conditions leading to more than 90% purity in both outlet streams have been identified, together with those achieving optimal performance. Regions leading to complete separation are observed and explained theoretically. As the mass-transfer effect was not considered, the triangle theory only gives initial guesses for the optimal operating conditions.
文摘The objective of the present study was to determine the proper sources and concentrations of soybean lecithin （phosphatidylcholine, PC） to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin （20% and 95% soybean phosphatidylcholine; PC20 and PC95） and three concentrations （1%, 2% and 3% v/v） of PC20 and PC95 supplemented in Tris-citric acid-fructose （TCF） extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ （equilibration）. The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender （P 〈 0.05）. Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders （P 〈 0.05）. PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 （P 〈 0.05）. It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% （v/v） is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs .
