Effects of space velocity, reaction temperature and support acidity on product distribution and induction period in 1-butene isomerization and metathesis over Mo/mordenite-alumina were investigated. As revealed by the...Effects of space velocity, reaction temperature and support acidity on product distribution and induction period in 1-butene isomerization and metathesis over Mo/mordenite-alumina were investigated. As revealed by the catalytic performance results, induction period and objective product were closely related to the reaction conditions. Lower space velocity led to longer induction period and higher propene yield. The optimal reaction temperature for propene production is around 150 ~C and it shifted to 100 ~C for ethene production. 1-Butene auto-metathesis predominated in the reaction network if the support with lower degree of sodium exchanged. And propene gradually became the dominant product upon increasing the support sodium exchange degree. 6Mo/H100Na0M-30A1 catalyst with a support of full sodium exchange degree exhibited the highest propene yield.展开更多
The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formatio...The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran + water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.展开更多
Fouling inductinn period of CaCO3 on heated surface was studied with the micro video technology. The rates of nucleating and nuclei growlng were measured under various experlmen-tal conditions. The experimental resul...Fouling inductinn period of CaCO3 on heated surface was studied with the micro video technology. The rates of nucleating and nuclei growlng were measured under various experlmen-tal conditions. The experimental results showed that both nucleating and nudel growing rates of CaCO3 increased obviously with surface temperature and concentration of reagents, In addition, the experiment of fouling induction period on the surface material of chemical plated nickel-phosphorus-indicated thnt not only the nucleate rate of CaCO3 decreased but also some fouling particles with certain size were easy to peel off from the heated surface under shearing streas, which means that the property of surface material is one of the rnont important factors influencing fouling induction periods.展开更多
A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation...A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation degree and temperature.Magnetic field has nearly no impact on it,while the use of ultrasound reduces it obviously.The impacts of some impurities and additives on primary nucleation were investigated.It is found that the presence of Na2SO4,NH4Cl,(NH4)2SO4 and EDTA disodium prolongs induction period,whereas KCl,NaCl,NaBr and CH4N2O can decrease it.Many important parameters of primary nucleation are also obtained,as temperature goes up from 283 to 313 K,interfacial tension decreases from 44.8 to 41.5 mJ/m2,contact angle varies from 82.9o to 88.7o,nucleation order is between 5.0 and 5.4,surface entropy factors are all above 5,suggesting that the growth mechanism is a spiral growth.Besides,both the homogeneous and heterogeneous primary nucleations were monitored with on-line focused beam reflectance measurement.展开更多
In this paper, the effect of MMT on the induction period of unleaded motor gasoline was studied, the manganese concentration, storage period of MMT-blended gasoline and environmental variables such as temperature and ...In this paper, the effect of MMT on the induction period of unleaded motor gasoline was studied, the manganese concentration, storage period of MMT-blended gasoline and environmental variables such as temperature and radiation intensity were considered to be main factors affecting the induction period of gasoline,when MMT-blended gasoline was exposed to light. It is found from experiments that the addition of MMT can improve the induction period of gasoline that is shielded from light, and reduce the induction period remarkably,when the gasoline is exposed to light. However, the radiation intensity is proved to be the leading influencing factor among all the environmental variables investigated.展开更多
Background: The ripeness of the cervix is of critical importance to the probability of successful labour induction. Aim: To determine the relationship between successful induction of labour and Bishop score. Materials...Background: The ripeness of the cervix is of critical importance to the probability of successful labour induction. Aim: To determine the relationship between successful induction of labour and Bishop score. Materials and Methods: A retrospective study of all obstetric patients who had induction of labour between January 1st 2012 and December 31st 2015 was done in Federal Teaching Hospital Abakaliki. The information obtained from patients’ case notes was analyzed using descriptive and inferential statistics at an alpha level of 0.05 for all statistical tests. Results: During the study period, there were 9548 deliveries;2.76% (264) was by induction of labour with success rate of 75.4%. The mean age of the women was 28.4 ± 5.8 years;majority where nulliparous (45.45%). The most common indication for induction of labour was postdatism (43.94%). Success of induction of labour was most likely at Bishop score of 8 to 10 (OR = 0.79, 95% CI 0.72 - 0.84). Induction delivery interval was shortest with use of Foley catheter and misoprostol. Conclusion: Our study has shown that success of induction of labour was most likely at Bishop Score of 8 - 10. We advocate the use of Foley catheter and misoprostol for cervical ripening especially when there is need to expedite delivery.展开更多
Objective:To investigate the effects of dexmedetomidine + propofol intervention during general anesthesia induction on endotracheal intubation.Methods: A total of 218 patients receiving tracheal intubation general ane...Objective:To investigate the effects of dexmedetomidine + propofol intervention during general anesthesia induction on endotracheal intubation.Methods: A total of 218 patients receiving tracheal intubation general anesthesia in the hospital between January 2017 and December 2017 were divided into the control group (n=109) and the dexmedetomidine group (n=109) by random number table method. Control group underwent routine propofol anesthesia induction and dexmedetomidine group underwent dexmedetomidine anesthesia induction on the basis of propofol. The differences in the severity of inflammatory response and stress response were compared between the two groups of patients after general anesthesia induction (T0), 1 min after endotracheal intubation (T1), 5 min after endotracheal intubation (T2) and 10 min after endotracheal intubation (T3).Results:At T0, there was no statistically significant difference in serum levels of inflammatory factors and stress hormones between the two groups. At T1, T2 and T3, serum inflammatory factors CRP, IL-1, IL-6, IL-8 and TNF-α levels of dexmedetomidine group were lower than those of control group;serum stress hormones ACTH, Cor, NE, AngⅠ and AngⅡ levels were lower than those of control group. Conclusion: Dexmedetomidine + propofol general anesthesia induction can effectively reduce the inflammatory stress response caused by endotracheal intubation.展开更多
基金the National Natural Science Foundation of China(Grant No.20903088 and 21006104)
文摘Effects of space velocity, reaction temperature and support acidity on product distribution and induction period in 1-butene isomerization and metathesis over Mo/mordenite-alumina were investigated. As revealed by the catalytic performance results, induction period and objective product were closely related to the reaction conditions. Lower space velocity led to longer induction period and higher propene yield. The optimal reaction temperature for propene production is around 150 ~C and it shifted to 100 ~C for ethene production. 1-Butene auto-metathesis predominated in the reaction network if the support with lower degree of sodium exchanged. And propene gradually became the dominant product upon increasing the support sodium exchange degree. 6Mo/H100Na0M-30A1 catalyst with a support of full sodium exchange degree exhibited the highest propene yield.
基金the National 973 Program of China (No. 2001CB209107) the National 863 Project of China (No. 2002AA615120) Huo Yingdong Education Foundation.
文摘The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran + water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.
基金Supported by the National Natural Science Foundation of China.
文摘Fouling inductinn period of CaCO3 on heated surface was studied with the micro video technology. The rates of nucleating and nuclei growlng were measured under various experlmen-tal conditions. The experimental results showed that both nucleating and nudel growing rates of CaCO3 increased obviously with surface temperature and concentration of reagents, In addition, the experiment of fouling induction period on the surface material of chemical plated nickel-phosphorus-indicated thnt not only the nucleate rate of CaCO3 decreased but also some fouling particles with certain size were easy to peel off from the heated surface under shearing streas, which means that the property of surface material is one of the rnont important factors influencing fouling induction periods.
基金Supported by Shanghai Leading Academic Discipline Project (No.B506)Program for New Century Excellent Talents in University (No. NCET-08-0776)
文摘A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation degree and temperature.Magnetic field has nearly no impact on it,while the use of ultrasound reduces it obviously.The impacts of some impurities and additives on primary nucleation were investigated.It is found that the presence of Na2SO4,NH4Cl,(NH4)2SO4 and EDTA disodium prolongs induction period,whereas KCl,NaCl,NaBr and CH4N2O can decrease it.Many important parameters of primary nucleation are also obtained,as temperature goes up from 283 to 313 K,interfacial tension decreases from 44.8 to 41.5 mJ/m2,contact angle varies from 82.9o to 88.7o,nucleation order is between 5.0 and 5.4,surface entropy factors are all above 5,suggesting that the growth mechanism is a spiral growth.Besides,both the homogeneous and heterogeneous primary nucleations were monitored with on-line focused beam reflectance measurement.
文摘In this paper, the effect of MMT on the induction period of unleaded motor gasoline was studied, the manganese concentration, storage period of MMT-blended gasoline and environmental variables such as temperature and radiation intensity were considered to be main factors affecting the induction period of gasoline,when MMT-blended gasoline was exposed to light. It is found from experiments that the addition of MMT can improve the induction period of gasoline that is shielded from light, and reduce the induction period remarkably,when the gasoline is exposed to light. However, the radiation intensity is proved to be the leading influencing factor among all the environmental variables investigated.
文摘Background: The ripeness of the cervix is of critical importance to the probability of successful labour induction. Aim: To determine the relationship between successful induction of labour and Bishop score. Materials and Methods: A retrospective study of all obstetric patients who had induction of labour between January 1st 2012 and December 31st 2015 was done in Federal Teaching Hospital Abakaliki. The information obtained from patients’ case notes was analyzed using descriptive and inferential statistics at an alpha level of 0.05 for all statistical tests. Results: During the study period, there were 9548 deliveries;2.76% (264) was by induction of labour with success rate of 75.4%. The mean age of the women was 28.4 ± 5.8 years;majority where nulliparous (45.45%). The most common indication for induction of labour was postdatism (43.94%). Success of induction of labour was most likely at Bishop score of 8 to 10 (OR = 0.79, 95% CI 0.72 - 0.84). Induction delivery interval was shortest with use of Foley catheter and misoprostol. Conclusion: Our study has shown that success of induction of labour was most likely at Bishop Score of 8 - 10. We advocate the use of Foley catheter and misoprostol for cervical ripening especially when there is need to expedite delivery.
文摘Objective:To investigate the effects of dexmedetomidine + propofol intervention during general anesthesia induction on endotracheal intubation.Methods: A total of 218 patients receiving tracheal intubation general anesthesia in the hospital between January 2017 and December 2017 were divided into the control group (n=109) and the dexmedetomidine group (n=109) by random number table method. Control group underwent routine propofol anesthesia induction and dexmedetomidine group underwent dexmedetomidine anesthesia induction on the basis of propofol. The differences in the severity of inflammatory response and stress response were compared between the two groups of patients after general anesthesia induction (T0), 1 min after endotracheal intubation (T1), 5 min after endotracheal intubation (T2) and 10 min after endotracheal intubation (T3).Results:At T0, there was no statistically significant difference in serum levels of inflammatory factors and stress hormones between the two groups. At T1, T2 and T3, serum inflammatory factors CRP, IL-1, IL-6, IL-8 and TNF-α levels of dexmedetomidine group were lower than those of control group;serum stress hormones ACTH, Cor, NE, AngⅠ and AngⅡ levels were lower than those of control group. Conclusion: Dexmedetomidine + propofol general anesthesia induction can effectively reduce the inflammatory stress response caused by endotracheal intubation.