A novel Enterococcus faecalis strain designated N J402 was found with high activity of arginine deiminase (ADI). The optimum condition for catalytic activity was determined in terms of temperature (about 40℃), th...A novel Enterococcus faecalis strain designated N J402 was found with high activity of arginine deiminase (ADI). The optimum condition for catalytic activity was determined in terms of temperature (about 40℃), thermostability (available 37℃) and pH (6-7). The effects of substrate and product concentration were studied. The effects of various metal ions added in reaction mixtures on the biocatalyst were investigated and ADI of N J402 was found to exhibit Co^2+ dependence, different from previous reports. Surfactant, cetyl trimethyl ammonium bromide, was one of the most important keys for producing L-citrulline. The enzyme in resting cells possessed the quality of high stability for reuse.展开更多
Dimethyl carbonate is an environmentally benign and biodegradable chemical.Based on integration of reactive distillation and pressure-swing distillation technologies,a novel process for synthesis of dimethyl carbonate...Dimethyl carbonate is an environmentally benign and biodegradable chemical.Based on integration of reactive distillation and pressure-swing distillation technologies,a novel process for synthesis of dimethyl carbonate through transesterification with propylene carbonate and methanol has been developed by Huang et al.In this work,the optimization of this process was performed by minimizing the total TAC.The results show that the optimal design flowsheet can save energy consumption by 18.6% with the propylene carbonate conversion of 99.9%.Then,an effective plant-wide control structure for the process was developed.Dynamic simulation results demonstrate that the temperature/flow rate cascade control plus with simple temperature control can keep not only product purity but also the conversion of the reactant at their desired values in the face of the disturbance in reactant feed flow rate and feed composition.展开更多
To explore the problems of monitoring chemical processes with large numbers of input parameters, a method based on Auto-associative Hierarchical Neural Network(AHNN) is proposed. AHNN focuses on dealing with datasets ...To explore the problems of monitoring chemical processes with large numbers of input parameters, a method based on Auto-associative Hierarchical Neural Network(AHNN) is proposed. AHNN focuses on dealing with datasets in high-dimension. AHNNs consist of two parts: groups of subnets based on well trained Autoassociative Neural Networks(AANNs) and a main net. The subnets play an important role on the performance of AHNN. A simple but effective method of designing the subnets is developed in this paper. In this method,the subnets are designed according to the classification of the data attributes. For getting the classification, an effective method called Extension Data Attributes Classification(EDAC) is adopted. Soft sensor using AHNN based on EDAC(EDAC-AHNN) is introduced. As a case study, the production data of Purified Terephthalic Acid(PTA) solvent system are selected to examine the proposed model. The results of the EDAC-AHNN model are compared with the experimental data extracted from the literature, which shows the efficiency of the proposed model.展开更多
A process for the production of glycerol carbonate(GC) is proposed with the transesterification of glycerol(GL)and dimethyl carbonate(DMC) with CaO as catalyst by reactive distillation and extractive distillation. The...A process for the production of glycerol carbonate(GC) is proposed with the transesterification of glycerol(GL)and dimethyl carbonate(DMC) with CaO as catalyst by reactive distillation and extractive distillation. The performance of solvents in separating DMC-methanol azeotrope and the effects of operation parameters on the reactive distillation process are investigated experimentally. The results indicate that both the GL conversion and GC yield increase with the DMC/GL molar ratio, reflux ratio, final temperature of tower bottom, and CaO/GL molar ratio and decrease as the recycle number of CaO increases. The calcium concentration in the residual reaction mixture also decreases remarkably as the DMC/GL molar ratio increases. At DMC/GL molar ratio 4.0, reflux ratio 1.0, final temperature of tower bottom 358 K, and CaO/GL molar ratio 0.05, both the GL conversion and GC yield can reach above 99.0%, and the mass concentration of calcium in the product is less than 0.08%.展开更多
Objective: The present study is to observe and compare the different effects of electroacupuncture(EA) at acupoint Neiguan (PC 6), intravenous administration of L-arginine(L-Arg, a precursor of nitric oxide), a...Objective: The present study is to observe and compare the different effects of electroacupuncture(EA) at acupoint Neiguan (PC 6), intravenous administration of L-arginine(L-Arg, a precursor of nitric oxide), and the drug administration combined with the EA on acute myocardial ischemia(AMI) in rats. Methods. The rat model of AMI was established by occlusion of the anterior descending branch of the left coronary artery, then the animals were divided randomly into 5 groups, i.e. control group, AMI group, L-Arg treatment group, EA treatment group and L-Arg plus EA treatment group, the mean arterial pressure(MAP), heart rate(HR) and the cardiac functions were observed and recorded. Results: The data showed that MAP, HR and all the indices of cardiac functions in the AMI group were significantly lower than those in control group, and the indices in each treatment group were all improved to different extents, especially in L-Arg plus EA treatment group. Conclusion.The combined use of L-Arg and EA had the better therapeutic effect on the AMI.展开更多
基金Supported by the Innovation Foundation of China (No. 02CJ-13-01-16).
文摘A novel Enterococcus faecalis strain designated N J402 was found with high activity of arginine deiminase (ADI). The optimum condition for catalytic activity was determined in terms of temperature (about 40℃), thermostability (available 37℃) and pH (6-7). The effects of substrate and product concentration were studied. The effects of various metal ions added in reaction mixtures on the biocatalyst were investigated and ADI of N J402 was found to exhibit Co^2+ dependence, different from previous reports. Surfactant, cetyl trimethyl ammonium bromide, was one of the most important keys for producing L-citrulline. The enzyme in resting cells possessed the quality of high stability for reuse.
基金Supported by the National Natural Science Foundation of China(21306025,21576053)the International Science&Technology Cooperation Program of China(2013DFR90540)
文摘Dimethyl carbonate is an environmentally benign and biodegradable chemical.Based on integration of reactive distillation and pressure-swing distillation technologies,a novel process for synthesis of dimethyl carbonate through transesterification with propylene carbonate and methanol has been developed by Huang et al.In this work,the optimization of this process was performed by minimizing the total TAC.The results show that the optimal design flowsheet can save energy consumption by 18.6% with the propylene carbonate conversion of 99.9%.Then,an effective plant-wide control structure for the process was developed.Dynamic simulation results demonstrate that the temperature/flow rate cascade control plus with simple temperature control can keep not only product purity but also the conversion of the reactant at their desired values in the face of the disturbance in reactant feed flow rate and feed composition.
基金Supported by the National Natural Science Foundation of China(61074153)
文摘To explore the problems of monitoring chemical processes with large numbers of input parameters, a method based on Auto-associative Hierarchical Neural Network(AHNN) is proposed. AHNN focuses on dealing with datasets in high-dimension. AHNNs consist of two parts: groups of subnets based on well trained Autoassociative Neural Networks(AANNs) and a main net. The subnets play an important role on the performance of AHNN. A simple but effective method of designing the subnets is developed in this paper. In this method,the subnets are designed according to the classification of the data attributes. For getting the classification, an effective method called Extension Data Attributes Classification(EDAC) is adopted. Soft sensor using AHNN based on EDAC(EDAC-AHNN) is introduced. As a case study, the production data of Purified Terephthalic Acid(PTA) solvent system are selected to examine the proposed model. The results of the EDAC-AHNN model are compared with the experimental data extracted from the literature, which shows the efficiency of the proposed model.
基金Supported by the National Natural Science Foundation of China(21106050)Specialized Research Fund for the Doctoral Program of Higher Education(20100142120066)
文摘A process for the production of glycerol carbonate(GC) is proposed with the transesterification of glycerol(GL)and dimethyl carbonate(DMC) with CaO as catalyst by reactive distillation and extractive distillation. The performance of solvents in separating DMC-methanol azeotrope and the effects of operation parameters on the reactive distillation process are investigated experimentally. The results indicate that both the GL conversion and GC yield increase with the DMC/GL molar ratio, reflux ratio, final temperature of tower bottom, and CaO/GL molar ratio and decrease as the recycle number of CaO increases. The calcium concentration in the residual reaction mixture also decreases remarkably as the DMC/GL molar ratio increases. At DMC/GL molar ratio 4.0, reflux ratio 1.0, final temperature of tower bottom 358 K, and CaO/GL molar ratio 0.05, both the GL conversion and GC yield can reach above 99.0%, and the mass concentration of calcium in the product is less than 0.08%.
基金supported by Shanghai Municipal Health Bureau(20003)
文摘Objective: The present study is to observe and compare the different effects of electroacupuncture(EA) at acupoint Neiguan (PC 6), intravenous administration of L-arginine(L-Arg, a precursor of nitric oxide), and the drug administration combined with the EA on acute myocardial ischemia(AMI) in rats. Methods. The rat model of AMI was established by occlusion of the anterior descending branch of the left coronary artery, then the animals were divided randomly into 5 groups, i.e. control group, AMI group, L-Arg treatment group, EA treatment group and L-Arg plus EA treatment group, the mean arterial pressure(MAP), heart rate(HR) and the cardiac functions were observed and recorded. Results: The data showed that MAP, HR and all the indices of cardiac functions in the AMI group were significantly lower than those in control group, and the indices in each treatment group were all improved to different extents, especially in L-Arg plus EA treatment group. Conclusion.The combined use of L-Arg and EA had the better therapeutic effect on the AMI.