In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde m...In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations.The 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression analysis.Minitab (Minitab 15 trial version) and MATLAB (R2010a trial version) were used for data analysis.The t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3),the linear terms of acetone:formaldehyde molar ratio (X1),reaction time (X4) followed by the square effects of acetone/formaldehyde molar ratio (X1X1).The optimized results were achieved with the acetone:formaldehyde molar ratio (mol/mol) at 3:1,solution pH value at 6.0,reaction temperature at 70℃,and reaction time at 140 min,respectively.This method can not only significantly reduce the number and cost of the tests,but also provide a good experimental design strategy for the development of furan resin.The investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.展开更多
对来源于Lactobacillus plantarum ST-Ⅲ菌株的胆盐水解酶基因bsh1在工程菌E.coli BL21/pET28b-bsh1中的表达条件进行了优化。首先通过一系列单因素实验对影响工程菌发酵条件的因素水平进行筛选。然后将诱导培养时间、诱导剂异丙基硫代-...对来源于Lactobacillus plantarum ST-Ⅲ菌株的胆盐水解酶基因bsh1在工程菌E.coli BL21/pET28b-bsh1中的表达条件进行了优化。首先通过一系列单因素实验对影响工程菌发酵条件的因素水平进行筛选。然后将诱导培养时间、诱导剂异丙基硫代-β-D-半乳糖苷(isopropylthio-D-galactoside,IPTG)浓度、胆盐浓度、装液量4个影响因素进行正交试验。在最佳工艺条件下得到的胆盐水解酶BSH比酶活达817.73 U。展开更多
文摘In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations.The 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression analysis.Minitab (Minitab 15 trial version) and MATLAB (R2010a trial version) were used for data analysis.The t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3),the linear terms of acetone:formaldehyde molar ratio (X1),reaction time (X4) followed by the square effects of acetone/formaldehyde molar ratio (X1X1).The optimized results were achieved with the acetone:formaldehyde molar ratio (mol/mol) at 3:1,solution pH value at 6.0,reaction temperature at 70℃,and reaction time at 140 min,respectively.This method can not only significantly reduce the number and cost of the tests,but also provide a good experimental design strategy for the development of furan resin.The investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.
文摘对来源于Lactobacillus plantarum ST-Ⅲ菌株的胆盐水解酶基因bsh1在工程菌E.coli BL21/pET28b-bsh1中的表达条件进行了优化。首先通过一系列单因素实验对影响工程菌发酵条件的因素水平进行筛选。然后将诱导培养时间、诱导剂异丙基硫代-β-D-半乳糖苷(isopropylthio-D-galactoside,IPTG)浓度、胆盐浓度、装液量4个影响因素进行正交试验。在最佳工艺条件下得到的胆盐水解酶BSH比酶活达817.73 U。