[Objectives] To optimize the extraction process of total flavonoids in stems of Mallotus apelta. [Methods]On the basis of singlefactor test,with volume fraction of ethanol,extraction time and ratio of solvent as indep...[Objectives] To optimize the extraction process of total flavonoids in stems of Mallotus apelta. [Methods]On the basis of singlefactor test,with volume fraction of ethanol,extraction time and ratio of solvent as independent variables,the content of total flavonoids as dependent variables,the completely secondary response surface regression fitting was conducted on the independent and dependent variables,and the Response Surface Method was used to optimize the optimum extraction process of total flavonoids in Mallotus apelta stems and predict the optimum process. [Results] The optimum extraction process of total flavonoids in Mallotus apelta was determined as follows: ethanol concentration of 71. 5%; extraction time of 154. 6 min; solid-liquid ratio of 1∶19. 2; total flavonoids content of 7. 060 mg/g; fitted binomial squared correlation coefficient R^2= 0. 8751.[Conclusions]Composite Design/Response Surface Method could be used in the extraction process optimization of total flavonoids in Mallotus apelta stems,the mathematical model established had high prediction accuracy,the method was simple and operability was good.展开更多
The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was use...The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was used for the optimization.Independent variables were extraction temperature,extraction pressure and entrainer flow rate.Dependent variable was yield ratio of icariin from Herba Epimedii.A two-order polynomial equation was fitted to the data.The results showed that the optimum extraction conditions were as follows:extraction temperature 46.5℃,extraction pressure 30.6 MPa,entrainer flow rate 3.3 mL/min.CCD/ RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.展开更多
The aim of the present study was to optimize the supercritical CO2 extraction conditions of icariin from Herba Epimedii by response surface method （RSM） and central composite design （CCD）. A 3-factor, 5-level CCD ...The aim of the present study was to optimize the supercritical CO2 extraction conditions of icariin from Herba Epimedii by response surface method （RSM） and central composite design （CCD）. A 3-factor, 5-level CCD was used for the optimization. Independent variables were extraction temperature, extraction pressure and entrainer flow rate. Dependent variable was yield ratio of icariin from Herba Epimedii. A two-order polynomial equation was fitted to the data. The results showed that the optimum extraction conditions were as follows： extraction temperature 46.5 ℃, extraction pressure 30.6 MPa, entrainer flow rate 3.3 mL/min. CCD/RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.展开更多
Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evo...Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evolution, and damage mechanics to simulate the growth of central cracks in cathode particles（Li Mn_2 O_4） by an extended finite element method by considering the influence of multiple factors. The simulation shows that particles are likely to crack at a high discharge rate, when the particle radius is large, or when the initial central crack is longer. It also shows that the maximum principal tensile stress decreases and cracking becomes more difficult when the influence of crack surface diffusion is considered. The fracturing process occurs according to the following stages： no crack growth, stable crack growth, and unstable crack growth. Changing the charge/discharge strategy before unstable crack growth sets in is beneficial to prevent further capacity fading during electrochemical cycling.展开更多
Papaya,a tropical fruit was used as the raw material to produce sauerkraut in the study.Three lactic acid bacteria strains isolated from papaya were added to the sauerkraut to facilitate the fermentation of papaya sau...Papaya,a tropical fruit was used as the raw material to produce sauerkraut in the study.Three lactic acid bacteria strains isolated from papaya were added to the sauerkraut to facilitate the fermentation of papaya sauerkraut.In the fermentation process,the dynamic changes of total acid in sauerkrauts at different levels of sugar concentration,salt concentration,inoculation and temperature were studied.The response surface method was used to study the effects of changes in multiple factors at the same time.On the basis of“one-variable-at-a-time”approach,the response surface method optimized papaya sauerkraut fermentation process.According to the change of total acid in single factor,29 experiments were designed by 4×3 factorial central composite design.The optimum fermentation conditions were obtained as follows:sugar at 3.8%,salt at 2.8%,inoculation at 5%,and temperature at 31℃.展开更多
基金Supported by Chinese Medicine Science and Technology Project of Guangxi Administration of Traditional Chinese Medicine(GZLC14-31)Science and Technology Research and Development Program of Guilin Bureau of Technology(20130403-4)+1 种基金Guangxi"2011 Collaborative Innovation Center"-Zhuang and Yao Medicine Collaborative Innovation Center(Gui201320)the Autonomous Region-Level College Students’ Innovation and Entrepreneurship Training Program(201710601082)
文摘[Objectives] To optimize the extraction process of total flavonoids in stems of Mallotus apelta. [Methods]On the basis of singlefactor test,with volume fraction of ethanol,extraction time and ratio of solvent as independent variables,the content of total flavonoids as dependent variables,the completely secondary response surface regression fitting was conducted on the independent and dependent variables,and the Response Surface Method was used to optimize the optimum extraction process of total flavonoids in Mallotus apelta stems and predict the optimum process. [Results] The optimum extraction process of total flavonoids in Mallotus apelta was determined as follows: ethanol concentration of 71. 5%; extraction time of 154. 6 min; solid-liquid ratio of 1∶19. 2; total flavonoids content of 7. 060 mg/g; fitted binomial squared correlation coefficient R^2= 0. 8751.[Conclusions]Composite Design/Response Surface Method could be used in the extraction process optimization of total flavonoids in Mallotus apelta stems,the mathematical model established had high prediction accuracy,the method was simple and operability was good.
文摘The aim of the present study was to optimize the supercritical CO_2 extraction conditions of icariin from Herba Epimedii by response surface method(RSM) and central composite design(CCD).A 3-factor,5-level CCD was used for the optimization.Independent variables were extraction temperature,extraction pressure and entrainer flow rate.Dependent variable was yield ratio of icariin from Herba Epimedii.A two-order polynomial equation was fitted to the data.The results showed that the optimum extraction conditions were as follows:extraction temperature 46.5℃,extraction pressure 30.6 MPa,entrainer flow rate 3.3 mL/min.CCD/ RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.
文摘The aim of the present study was to optimize the supercritical CO2 extraction conditions of icariin from Herba Epimedii by response surface method （RSM） and central composite design （CCD）. A 3-factor, 5-level CCD was used for the optimization. Independent variables were extraction temperature, extraction pressure and entrainer flow rate. Dependent variable was yield ratio of icariin from Herba Epimedii. A two-order polynomial equation was fitted to the data. The results showed that the optimum extraction conditions were as follows： extraction temperature 46.5 ℃, extraction pressure 30.6 MPa, entrainer flow rate 3.3 mL/min. CCD/RSM is convenient and highly predictive for optimizing the extraction process of icariin from Herba Epimedii.
基金support of the National Natural Science Foundation of China (11472165 and 11332005)
文摘Mechanical degradation, especially fractures in active particles in an electrode, is a major reason why the capacity of lithiumion batteries fades. This paper proposes a model that couples Li-ion diffusion, stress evolution, and damage mechanics to simulate the growth of central cracks in cathode particles（Li Mn_2 O_4） by an extended finite element method by considering the influence of multiple factors. The simulation shows that particles are likely to crack at a high discharge rate, when the particle radius is large, or when the initial central crack is longer. It also shows that the maximum principal tensile stress decreases and cracking becomes more difficult when the influence of crack surface diffusion is considered. The fracturing process occurs according to the following stages： no crack growth, stable crack growth, and unstable crack growth. Changing the charge/discharge strategy before unstable crack growth sets in is beneficial to prevent further capacity fading during electrochemical cycling.
基金The research is funded by Hainan University Research Funds Projects(No.kyqd1315)to serve local economic and social developmentAs a Hainan University project(2013),it is one of the Graduate Student Innovation Research Topics of Colleges and Universities in Hainan Province.
文摘Papaya,a tropical fruit was used as the raw material to produce sauerkraut in the study.Three lactic acid bacteria strains isolated from papaya were added to the sauerkraut to facilitate the fermentation of papaya sauerkraut.In the fermentation process,the dynamic changes of total acid in sauerkrauts at different levels of sugar concentration,salt concentration,inoculation and temperature were studied.The response surface method was used to study the effects of changes in multiple factors at the same time.On the basis of“one-variable-at-a-time”approach,the response surface method optimized papaya sauerkraut fermentation process.According to the change of total acid in single factor,29 experiments were designed by 4×3 factorial central composite design.The optimum fermentation conditions were obtained as follows:sugar at 3.8%,salt at 2.8%,inoculation at 5%,and temperature at 31℃.
