液相催化交换是氢-水同位素交换工艺的重要技术。本工作采用自行研制的大粒径4 mm柱型Pt-SDB催化剂与4 mm Dixon填料,开展了氢-水交换工艺实验研究。研究结果表明,在填料与催化剂体积填装比为1∶1时,等板高度最低,氢-水交换分离效果最好...液相催化交换是氢-水同位素交换工艺的重要技术。本工作采用自行研制的大粒径4 mm柱型Pt-SDB催化剂与4 mm Dixon填料,开展了氢-水交换工艺实验研究。研究结果表明,在填料与催化剂体积填装比为1∶1时,等板高度最低,氢-水交换分离效果最好;在50℃到70℃之间,随着催化交换反应温度升高,等板高度降低,当温度大于70℃时,等板高度变化不大,最优反应温度为70℃;随着气液比的增加,等板高度增大,气体流速比改变液体喷淋密度对等板高度的影响大。展开更多
According to the signed memorandum of cooperation between SAC and ISO, I participated in the two-month training and interactive work- ing program at ISO/CS and teamed about its experience in project management and inf...According to the signed memorandum of cooperation between SAC and ISO, I participated in the two-month training and interactive work- ing program at ISO/CS and teamed about its experience in project management and information system organization. During this period I gained a full understanding of the organizationat structure of ISO/CS as well as of its working and project management methods. I was also abte to estabtish a good communication and cooperation relationsbip with many of the departments. The outcome of this program has achieved its anticipated goat, and it witL certainty hetp and inspire me with my future work in this area.展开更多
To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operati...To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operation has been proposed based on the mixing pool model. The mass transfer and hydrodynamic data of structured packing, Mellapak 350Y, obtained in a high pressure tower have been used to test the validity of the proposed model. Compared with the SRP model and the Gualito model, it is found that for high pressure distillation process the present mathematical prediction shows a mean relative error of about 10% to the experimental data,the accuracy of which is the same as that by the Gualito model but better than that by the SRP model.展开更多
Asynchronous simulated moving bed chromatography (ASMBC), known also as the 'VARICOL' process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A d...Asynchronous simulated moving bed chromatography (ASMBC), known also as the 'VARICOL' process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.展开更多
Upon nitrogen step-down, Anabaena sp. PCC 7120 produces semi-regularly spaced heterocysts along filaments. HetR, the master regulator of heterocyst differenti- ation, has been shown to up-regulate hetP and hetZ in dif...Upon nitrogen step-down, Anabaena sp. PCC 7120 produces semi-regularly spaced heterocysts along filaments. HetR, the master regulator of heterocyst differenti- ation, has been shown to up-regulate hetP and hetZ in differentiating heterocysts via specific recognition sites. HetR is also predicted to bind to the promoter of patA, a gene required for heterocyst formation at intercalary positions. Here, we show that HetR binds to the predicted site 5′ from patA. Moreover, （1） deletion of the HetR-binding site greatly diminished the expression ofpatA in vegetative cells as shown with gfp, and （2） complementation of a patA mutant by a replicating plasmid that bears patA is largely prevented by removal of that binding site. In contrast, HetR- binding sites suppressed the expression of alr0202 （a homolog of hetZ） specifically in heterocysts and of alr3234 （a homolog of hetP） in whole filaments. Our results indicate that HetR can regulate gene expression in different modes.展开更多
文摘液相催化交换是氢-水同位素交换工艺的重要技术。本工作采用自行研制的大粒径4 mm柱型Pt-SDB催化剂与4 mm Dixon填料,开展了氢-水交换工艺实验研究。研究结果表明,在填料与催化剂体积填装比为1∶1时,等板高度最低,氢-水交换分离效果最好;在50℃到70℃之间,随着催化交换反应温度升高,等板高度降低,当温度大于70℃时,等板高度变化不大,最优反应温度为70℃;随着气液比的增加,等板高度增大,气体流速比改变液体喷淋密度对等板高度的影响大。
文摘According to the signed memorandum of cooperation between SAC and ISO, I participated in the two-month training and interactive work- ing program at ISO/CS and teamed about its experience in project management and information system organization. During this period I gained a full understanding of the organizationat structure of ISO/CS as well as of its working and project management methods. I was also abte to estabtish a good communication and cooperation relationsbip with many of the departments. The outcome of this program has achieved its anticipated goat, and it witL certainty hetp and inspire me with my future work in this area.
文摘To evaluate the influence of gas and liquid axial mixings on the separation efficiency of packed column, an approximate mathematical solution of HETP (equivalent height to a theoretical plate) under continuous operation has been proposed based on the mixing pool model. The mass transfer and hydrodynamic data of structured packing, Mellapak 350Y, obtained in a high pressure tower have been used to test the validity of the proposed model. Compared with the SRP model and the Gualito model, it is found that for high pressure distillation process the present mathematical prediction shows a mean relative error of about 10% to the experimental data,the accuracy of which is the same as that by the Gualito model but better than that by the SRP model.
基金Supported by the National Natural Science Foundation of China (No. 20206027), the Natural Science Foundation of Zhejiang Province (No. 202046)the National 973 Program of China (No. 2002CB312200).
文摘Asynchronous simulated moving bed chromatography (ASMBC), known also as the 'VARICOL' process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.
基金supported by the National Natural Science Foundation of China(31270132)
文摘Upon nitrogen step-down, Anabaena sp. PCC 7120 produces semi-regularly spaced heterocysts along filaments. HetR, the master regulator of heterocyst differenti- ation, has been shown to up-regulate hetP and hetZ in differentiating heterocysts via specific recognition sites. HetR is also predicted to bind to the promoter of patA, a gene required for heterocyst formation at intercalary positions. Here, we show that HetR binds to the predicted site 5′ from patA. Moreover, （1） deletion of the HetR-binding site greatly diminished the expression ofpatA in vegetative cells as shown with gfp, and （2） complementation of a patA mutant by a replicating plasmid that bears patA is largely prevented by removal of that binding site. In contrast, HetR- binding sites suppressed the expression of alr0202 （a homolog of hetZ） specifically in heterocysts and of alr3234 （a homolog of hetP） in whole filaments. Our results indicate that HetR can regulate gene expression in different modes.
