Methane conversion has been studied using gliding arc plasma in the presence of argon.The process was conducted at atmospheric pressure and ambient temperature.The focus of this research was to develop a process of co...Methane conversion has been studied using gliding arc plasma in the presence of argon.The process was conducted at atmospheric pressure and ambient temperature.The focus of this research was to develop a process of converting methane to C2 hydrocarbons and hydrogen. The main parameters,including the CH4/Ar mole ratio,the CH4 flow rate,the input voltage,and the minimum electrode gap,were varied to investigate their effects on methane conversion rate, product distribution,energy consumption,carbon deposit,and reaction stability.The specific energy requirement（SER） was used to express the energy utilization efficiency of the process and provided a practical guidance for optimizing reaction conditions for improving energy efficiency. It was found that the carbon deposition was not conducive to methane conversion,and the gliding arc plasma discharge reached a stable state twelve minutes later.Optimum conditions for methane conversion were suggested.The maximum methane conversion rate of 43.39%was obtained under the optimum conditions.Also,C2 hydrocarbons selectivity,C2 hydrocarbons yield,H2 selectivity, H2 yield and SER were 87.20%,37.83%,81.28%,35.27%,and 2.09 MJ/mol,respectively.展开更多
The plasma technology served as a tool in unconventional catalysis has been used in natural gas conversion,because the traditional catalytic methane oxidative coupling reaction must be performed at high temperature on...The plasma technology served as a tool in unconventional catalysis has been used in natural gas conversion,because the traditional catalytic methane oxidative coupling reaction must be performed at high temperature on account of the stability of methane molecule.The focus of this research is to develop a process of converting methane to C2 hydrocarbons with non-equilibrium plasma technology at room temperature and atmospheric pressure.It was found that methane conversion increased and the selectivity of C2 hydrocarbons decreased with the voltage.The optimum input voltage range was 40-80 V corresponding to high yield of C2 hydrocarbons.Methane conversion decreased and the selectivity of C2 hydrocarbons increased with the inlet flow rate of methane.The proper methane flow rate was 20-40 ml/min （corresponding residence time 10-20 s）.The experimental results show that methane conversion was 47% and the selectivity of C2 hydrocarbons was 40% under the proper condition using atmospheric DBD cold plasma technology.It was found that the breakdown voltage of methane VB was determined by the type of electrode and the discharge gap width in this glow discharge reactor.The breakdown voltage of methane VB,min derived from the Paschen law equation was established.展开更多
The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based so...The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2-2) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of manganese oxide species. The manganese oxide species increases oxygen mobility and oxygen vacancies in the CeO2 catalyst. Raman and Fourier Transform Infra Red (FT-IR) spectroscopies revealed the presence of lattice vibrations of metal-oxygen bondings and active sites in which the peaks corresponding to the bulk crystalline structures of Li2O, CaO, WO3 and MnO are detected. The performance of 5%MnO/15%CaO/CeO2 catalyst is the most potential among the CeO2-based catalysts, although lower than the 2%Li2O/MgO catalyst. The 2%Li2O/MgO catalyst showed the most promising C2+ hydrocarbons selectivity and yield at 98.0% and 5.7%, respectively.展开更多
Objective: To assess the safety and efficacy of herbal formulation rich in standardized fenugreek seed extract(IND-2) add-on therapy in type 2 diabetes mellitus(T2DM) patients who were on insulin treatment in prospect...Objective: To assess the safety and efficacy of herbal formulation rich in standardized fenugreek seed extract(IND-2) add-on therapy in type 2 diabetes mellitus(T2DM) patients who were on insulin treatment in prospective, single arm, open-label, uncontrolled, multicentre trial.Methods: T2DM patients(n=30) with aged 18-80 years who were stabilized on insulin treatment with fasting blood sugar(FBS) level between 100-140 mg/dL received IND-2 capsules(700 mg, thrice a day) for 16 weeks.The primary endpoints were an assessment of FBS at week 2, 4, 6, 8, 12 and 16.Secondary end-points include post-prandial blood sugar level, glycosylated Hb(HbA1c), reduction in the dose of insulin and number of hypoglycemic attacks, and improvement in lipid profile at various weeks.Safety and adverse events(AEs) were also assessed during the study.Results: Study was completed in twenty T2DM patients, and there was no significant reduction in FBS and post-prandial blood sugar level after addon therapy of IND-2.However, add-on therapy of IND-2 significantly reduced(P<0.01) the HbA1c values, requirements of insulin and hypoglycemic events as compared with baseline.Total cholesterol, high-density lipoproteins-cholesterol, and low-density lipoproteincholesterol levels were significantly increased(P<0.01) after IND-2 add-on therapy.Body weight and safety outcomes did not differ significantly in IND-2 add-on therapy group at week 16.Additionally, add-on therapy of IND-2 did not produce any serious adverse events.Conclusions: The results of present investigation suggest that add-on therapy of IND-2 with insulin in T2DM patients improves glycaemic control through a decrease in levels of HbA1c and number of insulin doses needed per day without an increase in body weight and risk of hypoglycemia.Thus, IND-2 may provide a safe and well-tolerated add-on therapy option for the management of T2DM.展开更多
The infrared emission spectra of methane, H, CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the tim...The infrared emission spectra of methane, H, CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the time and conditions of methane decomposition and C2 hydrocarbons formation were different. Methane conversion rate increased with the increase in the current and decrease in the amount of methane. Furthermore, an examination of the reaction mechanisms revealed that free radicals played an important role in the chain reaction.展开更多
This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temper...This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane （CO2 OCM） reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than 1.展开更多
Objective:To study the anti-HCV activity and mechanism of Hehuan Yin aqueous extract.Methods:Huh7.5.1 cells were used to establish the HCV2a virus infection model.Cell survival rate(%)and Renilla Luciferase Assay Kit(...Objective:To study the anti-HCV activity and mechanism of Hehuan Yin aqueous extract.Methods:Huh7.5.1 cells were used to establish the HCV2a virus infection model.Cell survival rate(%)and Renilla Luciferase Assay Kit(%)were calculated by Celltiter-GLO Assay for evaluating CC50,EC50 and SI values.To observe the drug resistance of the virus to different concentrations of Hehuan Yin within 72 hours by detecting luciferase activity,western-blot was used to detect the protein expression levels of NS5A,NS3 and NS5B.Results:the CC50,EC50 and SI of Hehuan Yin against HCV2a were 132.50g/ml,1.90g/ml and 67.90 respectively.The EC50 after 24h,48h and 72h administration were 18g/ml,5.8g/ml and 2.3g/ml respectively.Within the range of drug concentration,the aqueous extract Hehuan Yin had inhibitory effect on the expression of NS5A and NS5B proteins in a dose-effect relationship,but had no obvious effect on the expression of NS3 protein.Conclusion:The aqueous extract of Hehuan Yin may inhibit the replication of HCV2a virus by changing the protein expression levels of NS5A and NS5B,and the virus has no tolerance to the aqueous extract of Hehuan Yin.展开更多
Natural gas is not only playing an increasing important role in energy and chemicals supplies in 21st century but is also the second most important component of the greenhouse gases. Clean and direct conversion of met...Natural gas is not only playing an increasing important role in energy and chemicals supplies in 21st century but is also the second most important component of the greenhouse gases. Clean and direct conversion of methane to C 2 hydrocarbons (ethane, ethene and acetylene) through AC and DC plasma catalysis enhanced by electric field was studied at low temperature ranging from 50?℃ to 100?℃, atmospheric pressure and low power conditions. The influence of form of the electrode, distance between the electrodes, voltage, diameter of reactor, flow of inlet methane, N 2/CH 4(mole) and 20 catalysts were tested under low temperature plasma. The results indicated that best form of the electrode was plate; the better distance between the electrode was 5mm; the appropriate voltage was 38V(AC);the apparent diameter of reactor was 17mm, the likely flow range flux of inlet methane was 60—80?ml·min -1 , the suitable ratio of N 2/CH 4 (mole) was 0.5—1.0.The yield of C 2 hydrocarbons was the highest on V 2O 5,ZnO(5%)/ZSM-5-38 catalyst, the yield of ethene was the highest on La 0.8 Sr 0.2 CrO 3,ZnO catalyst. The results are better than those obtained through conventional reaction of oxidation coupling of methane.展开更多
基金supported by National Natural Science Foundation of China(Nos.21176175,- 20606023)
文摘Methane conversion has been studied using gliding arc plasma in the presence of argon.The process was conducted at atmospheric pressure and ambient temperature.The focus of this research was to develop a process of converting methane to C2 hydrocarbons and hydrogen. The main parameters,including the CH4/Ar mole ratio,the CH4 flow rate,the input voltage,and the minimum electrode gap,were varied to investigate their effects on methane conversion rate, product distribution,energy consumption,carbon deposit,and reaction stability.The specific energy requirement（SER） was used to express the energy utilization efficiency of the process and provided a practical guidance for optimizing reaction conditions for improving energy efficiency. It was found that the carbon deposition was not conducive to methane conversion,and the gliding arc plasma discharge reached a stable state twelve minutes later.Optimum conditions for methane conversion were suggested.The maximum methane conversion rate of 43.39%was obtained under the optimum conditions.Also,C2 hydrocarbons selectivity,C2 hydrocarbons yield,H2 selectivity, H2 yield and SER were 87.20%,37.83%,81.28%,35.27%,and 2.09 MJ/mol,respectively.
基金supported by the Research Foundation of SINOPEC under the Grant No. 404003the Research Foundation of Tianjin Scientific & Technology Committee under the Grant No. 043182611
文摘The plasma technology served as a tool in unconventional catalysis has been used in natural gas conversion,because the traditional catalytic methane oxidative coupling reaction must be performed at high temperature on account of the stability of methane molecule.The focus of this research is to develop a process of converting methane to C2 hydrocarbons with non-equilibrium plasma technology at room temperature and atmospheric pressure.It was found that methane conversion increased and the selectivity of C2 hydrocarbons decreased with the voltage.The optimum input voltage range was 40-80 V corresponding to high yield of C2 hydrocarbons.Methane conversion decreased and the selectivity of C2 hydrocarbons increased with the inlet flow rate of methane.The proper methane flow rate was 20-40 ml/min （corresponding residence time 10-20 s）.The experimental results show that methane conversion was 47% and the selectivity of C2 hydrocarbons was 40% under the proper condition using atmospheric DBD cold plasma technology.It was found that the breakdown voltage of methane VB was determined by the type of electrode and the discharge gap width in this glow discharge reactor.The breakdown voltage of methane VB,min derived from the Paschen law equation was established.
文摘The catalyst screening tests for carbon dioxide oxidative coupling of methane (CO2-OCM) have been investigated over ternary and binary metal oxide catalysts. The catalysts are prepared by doping MgO- and CeO2-based solids with oxides from alkali (Li2O), alkaline earth (CaO), and transition metal groups (WO3 or MnO). The presence of the peroxide (O2-2) active sites on the Li2O2, revealed by Raman spectroscopy, may be the key factor in the enhanced performance of some of the Li2O/MgO catalysts. The high reducibility of the CeO2 catalyst, an important factor in the CO2-OCM catalyst activity, may be enhanced by the presence of manganese oxide species. The manganese oxide species increases oxygen mobility and oxygen vacancies in the CeO2 catalyst. Raman and Fourier Transform Infra Red (FT-IR) spectroscopies revealed the presence of lattice vibrations of metal-oxygen bondings and active sites in which the peaks corresponding to the bulk crystalline structures of Li2O, CaO, WO3 and MnO are detected. The performance of 5%MnO/15%CaO/CeO2 catalyst is the most potential among the CeO2-based catalysts, although lower than the 2%Li2O/MgO catalyst. The 2%Li2O/MgO catalyst showed the most promising C2+ hydrocarbons selectivity and yield at 98.0% and 5.7%, respectively.
文摘Objective: To assess the safety and efficacy of herbal formulation rich in standardized fenugreek seed extract(IND-2) add-on therapy in type 2 diabetes mellitus(T2DM) patients who were on insulin treatment in prospective, single arm, open-label, uncontrolled, multicentre trial.Methods: T2DM patients(n=30) with aged 18-80 years who were stabilized on insulin treatment with fasting blood sugar(FBS) level between 100-140 mg/dL received IND-2 capsules(700 mg, thrice a day) for 16 weeks.The primary endpoints were an assessment of FBS at week 2, 4, 6, 8, 12 and 16.Secondary end-points include post-prandial blood sugar level, glycosylated Hb(HbA1c), reduction in the dose of insulin and number of hypoglycemic attacks, and improvement in lipid profile at various weeks.Safety and adverse events(AEs) were also assessed during the study.Results: Study was completed in twenty T2DM patients, and there was no significant reduction in FBS and post-prandial blood sugar level after addon therapy of IND-2.However, add-on therapy of IND-2 significantly reduced(P<0.01) the HbA1c values, requirements of insulin and hypoglycemic events as compared with baseline.Total cholesterol, high-density lipoproteins-cholesterol, and low-density lipoproteincholesterol levels were significantly increased(P<0.01) after IND-2 add-on therapy.Body weight and safety outcomes did not differ significantly in IND-2 add-on therapy group at week 16.Additionally, add-on therapy of IND-2 did not produce any serious adverse events.Conclusions: The results of present investigation suggest that add-on therapy of IND-2 with insulin in T2DM patients improves glycaemic control through a decrease in levels of HbA1c and number of insulin doses needed per day without an increase in body weight and risk of hypoglycemia.Thus, IND-2 may provide a safe and well-tolerated add-on therapy option for the management of T2DM.
基金supported by National Natural Science Foundation of ChinaDoctoral Foundation of Ministry of Education(20010698007)Returned Scholars Foundation of Ministry of Education(2001[345])
文摘The infrared emission spectra of methane, H, CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the time and conditions of methane decomposition and C2 hydrocarbons formation were different. Methane conversion rate increased with the increase in the current and decrease in the amount of methane. Furthermore, an examination of the reaction mechanisms revealed that free radicals played an important role in the chain reaction.
文摘This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane （CO2 OCM） reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than 1.
基金Natural Foundation of Guangdong Province(No.2018A030313308)。
文摘Objective:To study the anti-HCV activity and mechanism of Hehuan Yin aqueous extract.Methods:Huh7.5.1 cells were used to establish the HCV2a virus infection model.Cell survival rate(%)and Renilla Luciferase Assay Kit(%)were calculated by Celltiter-GLO Assay for evaluating CC50,EC50 and SI values.To observe the drug resistance of the virus to different concentrations of Hehuan Yin within 72 hours by detecting luciferase activity,western-blot was used to detect the protein expression levels of NS5A,NS3 and NS5B.Results:the CC50,EC50 and SI of Hehuan Yin against HCV2a were 132.50g/ml,1.90g/ml and 67.90 respectively.The EC50 after 24h,48h and 72h administration were 18g/ml,5.8g/ml and 2.3g/ml respectively.Within the range of drug concentration,the aqueous extract Hehuan Yin had inhibitory effect on the expression of NS5A and NS5B proteins in a dose-effect relationship,but had no obvious effect on the expression of NS3 protein.Conclusion:The aqueous extract of Hehuan Yin may inhibit the replication of HCV2a virus by changing the protein expression levels of NS5A and NS5B,and the virus has no tolerance to the aqueous extract of Hehuan Yin.
文摘Natural gas is not only playing an increasing important role in energy and chemicals supplies in 21st century but is also the second most important component of the greenhouse gases. Clean and direct conversion of methane to C 2 hydrocarbons (ethane, ethene and acetylene) through AC and DC plasma catalysis enhanced by electric field was studied at low temperature ranging from 50?℃ to 100?℃, atmospheric pressure and low power conditions. The influence of form of the electrode, distance between the electrodes, voltage, diameter of reactor, flow of inlet methane, N 2/CH 4(mole) and 20 catalysts were tested under low temperature plasma. The results indicated that best form of the electrode was plate; the better distance between the electrode was 5mm; the appropriate voltage was 38V(AC);the apparent diameter of reactor was 17mm, the likely flow range flux of inlet methane was 60—80?ml·min -1 , the suitable ratio of N 2/CH 4 (mole) was 0.5—1.0.The yield of C 2 hydrocarbons was the highest on V 2O 5,ZnO(5%)/ZSM-5-38 catalyst, the yield of ethene was the highest on La 0.8 Sr 0.2 CrO 3,ZnO catalyst. The results are better than those obtained through conventional reaction of oxidation coupling of methane.
