A sequential statistical approach was applied to optimizing the fermentation medium of epothilones（Epos） production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite a...A sequential statistical approach was applied to optimizing the fermentation medium of epothilones（Epos） production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and ultraviolet. The effects of different carbon sources and nitrogen sources on the fermentation medium were tested, and the suitable ones were selected. Then a uniform design was employed to design the experiments. A linear model was developed for identifying the significant components in fermentation medium, while a third degree polynomial model was used for studying the relationship between the concentration of the components in fermentation medium and the yield of Epos（YEPs）. A pattern search method was used for searching the optimum fermentation medium in the test space, which was as follows（g/L）： potassium nitrate 8.00, soybean peptone 17.60, potassium hydrogen phos- phate 1.00, beef extraction 6.46, yeast extraction 1.00, calcium chloride 0.25, sodium chloride 1.00 and ferric chloride 0.02. The optimum fermentation medium was expected to result in a yield of Epos（YEPs） of 2.48 mg/L. The validation experiments with the optimum medium were performed in triplicate and the average yield of Epos was 2.45 mg/L which was 7.78 times higher than that of Epos prepared without optimization.展开更多
The equations of electrodynamics for a gyrotropic medium by using Maxwell’s equa-tions are deduced.Through Fourier transformation,the admittances of TM and TE modes inthe electrically gyrotropic substrate and magneti...The equations of electrodynamics for a gyrotropic medium by using Maxwell’s equa-tions are deduced.Through Fourier transformation,the admittances of TM and TE modes inthe electrically gyrotropic substrate and magnetically gyrotropic substrate are given.Numericalresults of the dominant mode in magnetized ferrite-loaded double-layered finlines are presentedwhich could be used in designing finline ferrite devices.展开更多
The reaction course of urea synthesis from NH3 and CO2 was discussed on the basis of bimolecular reaction mode. It was considered probable that amino-formic acid is a vigorously corrosive intermediate product. An elec...The reaction course of urea synthesis from NH3 and CO2 was discussed on the basis of bimolecular reaction mode. It was considered probable that amino-formic acid is a vigorously corrosive intermediate product. An electrochemical corrosion mechanism of stainless steels and titanium in the urea medium was proposed.展开更多
The separation characteristic of raw coal from Luoyang mining area, China, was investigated by applying a dry coal beneficiation flowsheet with the dense medium gas-solid fluidized bed as main separating equipment. Th...The separation characteristic of raw coal from Luoyang mining area, China, was investigated by applying a dry coal beneficiation flowsheet with the dense medium gas-solid fluidized bed as main separating equipment. The experimental and simulation results indicate that the dense medium gas-solid fluidized bed can provide uniform distribution and stable fluctuation of bed densities at various heights. Two types of different separating approaches were compared using the dry coal beneficiation flowsheet. Compared with obtaining cleaning coal in the first stage of the flowsheet, a higher yield of the cleaning coal and better separation efficiency can be achieved when discharging gangue in the first stage. Finally, the results indicate that 64.86% pure cleaning coal with an ash content of 11.77% and 13.53% middlings were obtained, and 21.61% gangue was removed in two successive separation stages with the probable errors of 0.05 and 0.07 g/cm3, respectively.展开更多
Based on an equivalent medium approach, this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores. The influences of pores＇ nonlinea...Based on an equivalent medium approach, this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores. The influences of pores＇ nonlinear oscillations on sound attenuation, sound dispersion and an equivalent acoustic nonlinearity parameter are discussed. The calculated results show that the attenuation increases with an increasing volume fraction of micropores. The peak of sound velocity and attenuation occurs at the resonant frequency of the micropores while the peak of the equivalent acoustic nonlinearity parameter occurs at the half of the resonant frequency of the micropores. Furthermore, multiple scattering has been taken into account, which leads to a modification to the effective wave number in the equivalent medium approach. We find that these linear and nonlinear acoustic parameters need to be corrected when the volume fraction of micropores is larger than 0.1%.展开更多
In this article, the generalized model for thermoelastic waves with two relaxation times is utilized to compute the increment of temperature, the displacement components, the stress components, and the changes in the ...In this article, the generalized model for thermoelastic waves with two relaxation times is utilized to compute the increment of temperature, the displacement components, the stress components, and the changes in the volume fraction field in a two-dimensional porous medium. By using the Fourier-Laplace transform and the eigenvalue method, the considered variables are obtained analytically. The derived approach is estimated with numerical outcomes which are applied to the porous media with a geometrical simplification. The numerical results for the considered variables are performed and presented graphically. Finally, the outcomes are represented graphically to display the difference among the classical dynamical(CD) coupled, the Lord-Shulman(LS), and the Green-Lindsay(GL) models.展开更多
This research explores the transport of a Jeffrey fluid through a permeable slit of microchannel under the effect of a porous medium and constant reabsorption.Physical laws of fluid mechanics are used to study the flo...This research explores the transport of a Jeffrey fluid through a permeable slit of microchannel under the effect of a porous medium and constant reabsorption.Physical laws of fluid mechanics are used to study the flow in a cross-sectional area of a narrow slit which generates a highly nonlinear system of partial differential equation with nonhomogeneous boundary conditions.To solve the complex boundary value problem;a recursive(Langlois)approach is used and explicit expressions for velocity,pressure,stream function,flux,shear stress and fractional reabsorption are calculated.It is noticed that the flow rate at the centre line of slit and shear stress on the walls of slit decay due to the presence of porous medium and viscoelastic fluid parameters.It is also quantitatively observed that more pressure is required for the fluid flow when the slit is filled with a porous medium and reabsorption on the walls is constant.The mathematical results of the present research have significant importance in the field of biofluid mechanics and medical industry,therefore the application of a diseased rat kidney is also included in this research:and reabsorption velocities in the case of a diseased and a healthy rat kidney are calculated with the effects of a porous medium and constant re-absorption.展开更多
1.The development philosophy is the precursor of development action.It shapes the overarching framework,defines the fundamentals,sets the direction,and steers long-term progress,reflecting our approach,direction,and p...1.The development philosophy is the precursor of development action.It shapes the overarching framework,defines the fundamentals,sets the direction,and steers long-term progress,reflecting our approach,direction,and priorities in development.With the right development philosophy in place,objectives and tasks can be clearly defined and appropriate policies and measures can be accordingly formulated.展开更多
基金Supported by the Science Technology Development Project of Jilin Province,China(No.20020503-2)
文摘A sequential statistical approach was applied to optimizing the fermentation medium of epothilones（Epos） production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and ultraviolet. The effects of different carbon sources and nitrogen sources on the fermentation medium were tested, and the suitable ones were selected. Then a uniform design was employed to design the experiments. A linear model was developed for identifying the significant components in fermentation medium, while a third degree polynomial model was used for studying the relationship between the concentration of the components in fermentation medium and the yield of Epos（YEPs）. A pattern search method was used for searching the optimum fermentation medium in the test space, which was as follows（g/L）： potassium nitrate 8.00, soybean peptone 17.60, potassium hydrogen phos- phate 1.00, beef extraction 6.46, yeast extraction 1.00, calcium chloride 0.25, sodium chloride 1.00 and ferric chloride 0.02. The optimum fermentation medium was expected to result in a yield of Epos（YEPs） of 2.48 mg/L. The validation experiments with the optimum medium were performed in triplicate and the average yield of Epos was 2.45 mg/L which was 7.78 times higher than that of Epos prepared without optimization.
文摘The equations of electrodynamics for a gyrotropic medium by using Maxwell’s equa-tions are deduced.Through Fourier transformation,the admittances of TM and TE modes inthe electrically gyrotropic substrate and magnetically gyrotropic substrate are given.Numericalresults of the dominant mode in magnetized ferrite-loaded double-layered finlines are presentedwhich could be used in designing finline ferrite devices.
文摘The reaction course of urea synthesis from NH3 and CO2 was discussed on the basis of bimolecular reaction mode. It was considered probable that amino-formic acid is a vigorously corrosive intermediate product. An electrochemical corrosion mechanism of stainless steels and titanium in the urea medium was proposed.
基金Projects(51221462)supported by the National Natural Science Foundation of ChinaProject(2014QNA28)supported by the Fundamental Research Funds for the Central Universities,China
文摘The separation characteristic of raw coal from Luoyang mining area, China, was investigated by applying a dry coal beneficiation flowsheet with the dense medium gas-solid fluidized bed as main separating equipment. The experimental and simulation results indicate that the dense medium gas-solid fluidized bed can provide uniform distribution and stable fluctuation of bed densities at various heights. Two types of different separating approaches were compared using the dry coal beneficiation flowsheet. Compared with obtaining cleaning coal in the first stage of the flowsheet, a higher yield of the cleaning coal and better separation efficiency can be achieved when discharging gangue in the first stage. Finally, the results indicate that 64.86% pure cleaning coal with an ash content of 11.77% and 13.53% middlings were obtained, and 21.61% gangue was removed in two successive separation stages with the probable errors of 0.05 and 0.07 g/cm3, respectively.
基金supported by the National Natural Science Foundation of China (Grant No 10674066)State Key Laboratory of Acoustics (Grant No 200802)
文摘Based on an equivalent medium approach, this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores. The influences of pores＇ nonlinear oscillations on sound attenuation, sound dispersion and an equivalent acoustic nonlinearity parameter are discussed. The calculated results show that the attenuation increases with an increasing volume fraction of micropores. The peak of sound velocity and attenuation occurs at the resonant frequency of the micropores while the peak of the equivalent acoustic nonlinearity parameter occurs at the half of the resonant frequency of the micropores. Furthermore, multiple scattering has been taken into account, which leads to a modification to the effective wave number in the equivalent medium approach. We find that these linear and nonlinear acoustic parameters need to be corrected when the volume fraction of micropores is larger than 0.1%.
基金Project supported by the Deanship of Scientific Research (DSR),King Abdulaziz University,Jeddah(No.DF-782-130-1441)。
文摘In this article, the generalized model for thermoelastic waves with two relaxation times is utilized to compute the increment of temperature, the displacement components, the stress components, and the changes in the volume fraction field in a two-dimensional porous medium. By using the Fourier-Laplace transform and the eigenvalue method, the considered variables are obtained analytically. The derived approach is estimated with numerical outcomes which are applied to the porous media with a geometrical simplification. The numerical results for the considered variables are performed and presented graphically. Finally, the outcomes are represented graphically to display the difference among the classical dynamical(CD) coupled, the Lord-Shulman(LS), and the Green-Lindsay(GL) models.
文摘This research explores the transport of a Jeffrey fluid through a permeable slit of microchannel under the effect of a porous medium and constant reabsorption.Physical laws of fluid mechanics are used to study the flow in a cross-sectional area of a narrow slit which generates a highly nonlinear system of partial differential equation with nonhomogeneous boundary conditions.To solve the complex boundary value problem;a recursive(Langlois)approach is used and explicit expressions for velocity,pressure,stream function,flux,shear stress and fractional reabsorption are calculated.It is noticed that the flow rate at the centre line of slit and shear stress on the walls of slit decay due to the presence of porous medium and viscoelastic fluid parameters.It is also quantitatively observed that more pressure is required for the fluid flow when the slit is filled with a porous medium and reabsorption on the walls is constant.The mathematical results of the present research have significant importance in the field of biofluid mechanics and medical industry,therefore the application of a diseased rat kidney is also included in this research:and reabsorption velocities in the case of a diseased and a healthy rat kidney are calculated with the effects of a porous medium and constant re-absorption.
文摘1.The development philosophy is the precursor of development action.It shapes the overarching framework,defines the fundamentals,sets the direction,and steers long-term progress,reflecting our approach,direction,and priorities in development.With the right development philosophy in place,objectives and tasks can be clearly defined and appropriate policies and measures can be accordingly formulated.
