The aim of this study is to suppress a cavitation near the orifice of arelief valve by changing the shape of a poppet. An experimental flow visualization technique and anumerical cavitating flow simulation, using a RN...The aim of this study is to suppress a cavitation near the orifice of arelief valve by changing the shape of a poppet. An experimental flow visualization technique and anumerical cavitating flow simulation, using a RNG kappa-epsilon turbulence model and a cavitationmodel, are employed to achieve the purpose. In the flow visualization, the cavitation phenomenonnear the orifice of a relief valve is observed using a transparent test valve body model and acamera. On the other hand, a three dimensional cavitating flow simulation is conducted to predictthe cavitation near the orifice of a relief valve. Six types of poppets are designed by changing theshape of a traditional poppet shape, which is expected to influence the cavitating flow in anorifice. In addition, the cavitation noise of a relief valve is measured and the noise spectrum isanalyzed. In conclusion, the cavitation intensity and the cavitation noise are reduced for anoptimal poppet geometry obtained in the present study.展开更多
A Neural Network( NN ) approach to ABR flow control algorithm in ATM networks is proposed. The NN predicts the queue length, its variation and possible cell loss, then regulates the source rate adaptivel...A Neural Network( NN ) approach to ABR flow control algorithm in ATM networks is proposed. The NN predicts the queue length, its variation and possible cell loss, then regulates the source rate adaptively. Therefore, more appropriate value of the explicit rate can be determined in the corresponding field of the RM cells. This approach performs better than the traditional static feedback control. Additionally, the performance of this algorithm under CBR background traffic is discussed, and the simulatino results show that the neural network is also efficient.展开更多
SARS coronavirus is an RNA virus whose rep- lication is error-prone, which provides possibility for escape of host defenses, and even leads to evolution of new viral strains during the passage or the transmission. Lot...SARS coronavirus is an RNA virus whose rep- lication is error-prone, which provides possibility for escape of host defenses, and even leads to evolution of new viral strains during the passage or the transmission. Lots of varia- tions have been detected among different SARS-CoV strains. And a study on these variations is helpful for development of efficient vaccine. Moreover, the test of nucleic acid characterization and genetic stability of SARS-CoV is im- portant in the research of inactivated vaccine. The whole genome sequences of two SARS coronavirus strains after passage in Vero cell culture were determined and were com- pared with those of early passages, respectively. Results showed that both SARS coronavirus strains have high ge- netic stability, although nearly 10 generations were passed. Four nucleotide variations were observed between the sec- ond passage and the 11th passage of Sino1 strain for identi- fication of SARS inactivated vaccine. Moreover, only one nucleotide was different between the third passage and the 10th passage of Sino3 strain for SARS inactivated vaccine. Therefore, this study suggested it was possible to develop inactivated vaccine against SARS-CoV in the future.展开更多
A novel ATM switch fabric with bifurcated queuing is introduced. It can substantially decrease the speed requirement of both memory and bus of ATM switching systems while maintaining high throughput of basic o...A novel ATM switch fabric with bifurcated queuing is introduced. It can substantially decrease the speed requirement of both memory and bus of ATM switching systems while maintaining high throughput of basic output queuing.展开更多
We studied the infectious effect of SARS-CoV virus on juvenile and adult Brandt’s Vole (Microtus brandtii) by nasal cavity spraying method (CCID50 is 105.7). SARS virus caused serious deaths in adults. The death adul...We studied the infectious effect of SARS-CoV virus on juvenile and adult Brandt’s Vole (Microtus brandtii) by nasal cavity spraying method (CCID50 is 105.7). SARS virus caused serious deaths in adults. The death adults demonstrated hemorrhage from mouth, nasal cavity and intestine, hemorrhageious interstitial pneumonia and gore in liver, spleen and kidney. The survival adults demonstrated local hemorrhagic spot in lung and emphysema, but the other organs showed no pathological abnormality. SARS virus caused no deaths in juveniles, but locomotion of infected juveniles became slower. In the early stage, there was local pneumonia in lung and SARS viruses were isolated from the pathological tissue. Only one control juvenile lived and the infected juvenile showed local pneumonia in lung. The results demonstrated that SARS-CoV infected Brandt’s vole seriously and adults were more susceptive to SARS-CoV than juveniles. The Brandt’s vole may be a potential animal model for SARS research.展开更多
Microencapsulated genetically engineered bac- teria cells are a novel approach of oral therapy for uremia. Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5αcells through plasmid pKAU17...Microencapsulated genetically engineered bac- teria cells are a novel approach of oral therapy for uremia. Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5αcells through plasmid pKAU17. The transformant can use urea or ammonia as its sole nitrogen source through strain training. The urease ge- netically engineered bacteria cells are entrapped in polyvinyl alcohol (PVA) microcapsules, which can be used to remove urea from uremia patients. The mechanical strength of PVA microcapsules is significantly higher than that of APA microcapsules. This suggests that the problem of friability of APA can be solved in this way. The optimal conditions for the preparation of PVA microencapsulated genetically engi- neered bacterial cells are: polyvinyl alcohol (PVA, 2450±50) used as the carrier at a concentration 6%, the pH value of boric acid as crosslinking reagent 6.5, crosslinking time 24 h, entrapment ratio of bacteria 8 %, air flow rate of the encap- sulate device 3 L/min and liquid flow rate at 1 mL/10 min. The average diameter of microcapsules prepared under these optimal conditions is 20—40 mesh. Experiments in vitro showed that one hundred milligrams of wet bacterial cells in PVA microcapsules could remove 18.4 mg of urea in 4 h.展开更多
基金This project is supported by Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE, China (No.2002123) National Natural Science Foundation of China (No.50175097).
文摘The aim of this study is to suppress a cavitation near the orifice of arelief valve by changing the shape of a poppet. An experimental flow visualization technique and anumerical cavitating flow simulation, using a RNG kappa-epsilon turbulence model and a cavitationmodel, are employed to achieve the purpose. In the flow visualization, the cavitation phenomenonnear the orifice of a relief valve is observed using a transparent test valve body model and acamera. On the other hand, a three dimensional cavitating flow simulation is conducted to predictthe cavitation near the orifice of a relief valve. Six types of poppets are designed by changing theshape of a traditional poppet shape, which is expected to influence the cavitating flow in anorifice. In addition, the cavitation noise of a relief valve is measured and the noise spectrum isanalyzed. In conclusion, the cavitation intensity and the cavitation noise are reduced for anoptimal poppet geometry obtained in the present study.
文摘A Neural Network( NN ) approach to ABR flow control algorithm in ATM networks is proposed. The NN predicts the queue length, its variation and possible cell loss, then regulates the source rate adaptively. Therefore, more appropriate value of the explicit rate can be determined in the corresponding field of the RM cells. This approach performs better than the traditional static feedback control. Additionally, the performance of this algorithm under CBR background traffic is discussed, and the simulatino results show that the neural network is also efficient.
文摘SARS coronavirus is an RNA virus whose rep- lication is error-prone, which provides possibility for escape of host defenses, and even leads to evolution of new viral strains during the passage or the transmission. Lots of varia- tions have been detected among different SARS-CoV strains. And a study on these variations is helpful for development of efficient vaccine. Moreover, the test of nucleic acid characterization and genetic stability of SARS-CoV is im- portant in the research of inactivated vaccine. The whole genome sequences of two SARS coronavirus strains after passage in Vero cell culture were determined and were com- pared with those of early passages, respectively. Results showed that both SARS coronavirus strains have high ge- netic stability, although nearly 10 generations were passed. Four nucleotide variations were observed between the sec- ond passage and the 11th passage of Sino1 strain for identi- fication of SARS inactivated vaccine. Moreover, only one nucleotide was different between the third passage and the 10th passage of Sino3 strain for SARS inactivated vaccine. Therefore, this study suggested it was possible to develop inactivated vaccine against SARS-CoV in the future.
文摘A novel ATM switch fabric with bifurcated queuing is introduced. It can substantially decrease the speed requirement of both memory and bus of ATM switching systems while maintaining high throughput of basic output queuing.
基金supported by the Innovation Program of Institute of Zoology,the Chinese Academy of Sciences
文摘We studied the infectious effect of SARS-CoV virus on juvenile and adult Brandt’s Vole (Microtus brandtii) by nasal cavity spraying method (CCID50 is 105.7). SARS virus caused serious deaths in adults. The death adults demonstrated hemorrhage from mouth, nasal cavity and intestine, hemorrhageious interstitial pneumonia and gore in liver, spleen and kidney. The survival adults demonstrated local hemorrhagic spot in lung and emphysema, but the other organs showed no pathological abnormality. SARS virus caused no deaths in juveniles, but locomotion of infected juveniles became slower. In the early stage, there was local pneumonia in lung and SARS viruses were isolated from the pathological tissue. Only one control juvenile lived and the infected juvenile showed local pneumonia in lung. The results demonstrated that SARS-CoV infected Brandt’s vole seriously and adults were more susceptive to SARS-CoV than juveniles. The Brandt’s vole may be a potential animal model for SARS research.
文摘Microencapsulated genetically engineered bac- teria cells are a novel approach of oral therapy for uremia. Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5αcells through plasmid pKAU17. The transformant can use urea or ammonia as its sole nitrogen source through strain training. The urease ge- netically engineered bacteria cells are entrapped in polyvinyl alcohol (PVA) microcapsules, which can be used to remove urea from uremia patients. The mechanical strength of PVA microcapsules is significantly higher than that of APA microcapsules. This suggests that the problem of friability of APA can be solved in this way. The optimal conditions for the preparation of PVA microencapsulated genetically engi- neered bacterial cells are: polyvinyl alcohol (PVA, 2450±50) used as the carrier at a concentration 6%, the pH value of boric acid as crosslinking reagent 6.5, crosslinking time 24 h, entrapment ratio of bacteria 8 %, air flow rate of the encap- sulate device 3 L/min and liquid flow rate at 1 mL/10 min. The average diameter of microcapsules prepared under these optimal conditions is 20—40 mesh. Experiments in vitro showed that one hundred milligrams of wet bacterial cells in PVA microcapsules could remove 18.4 mg of urea in 4 h.
