There was heterogeneous distribution in stomatal conductance (g-s) and stomatal aperture for both high- and low-light leaves of Ligustrum sinense Lour. in four designated positions within a leaf. Linear or exponential...There was heterogeneous distribution in stomatal conductance (g-s) and stomatal aperture for both high- and low-light leaves of Ligustrum sinense Lour. in four designated positions within a leaf. Linear or exponential or polynomial relationships between g-s and stomatal aperture were found when regression of g-s and stomatal aperture was established. Statistical analysis revealed that the relationship between g-s and stomatal aperture for high-light leaves was more significant than that of low-light leaves. A linear relationship between g-s and stomatal aperture existed in both positions 1 and 3 for both high- and low-light leaves. The stomatal density of the low-light leaves was much lower than that of the high-light leaves. The sensitivity of stomata to changing environment for high-light leaves was higher than that for low-light leaves, which may also relate to the higher stomatal density for the high-light leaves.展开更多
A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce（III） and La（III）,are prepared by impregnation,characterized by inductively coupled plasma （ICP）,X-...A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce（III） and La（III）,are prepared by impregnation,characterized by inductively coupled plasma （ICP）,X-ray diffraction （XRD）,BET,temperature-programmed desorption of ammonia （NH3-TPD）,temperature-programmed reduction of hydrogen （H2-TPR） and H2-chemisorption techniques,and evaluated in the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor.The reaction temperature,time on stream,space velocity,and the ratio of H2/n-heptane are changed to get the optimal conditions.The Ce（III） and La（III）-exchanged Hβ-zeolites exhibit higher selectivity for isomerized products than the neat Hβ-zeolite.Moreover,the Ce（III）-exchanged catalysts give higher conversions of n-heptane,whereas the La（III）-exchanged ones do not show any improvement in con-version.Under optimal conditions,the catalyst with 0.4% （by mass） Pt and 0.5% （by mass） Ce loading presents very high selectivity of isomerized products of 95.1% coupled with high n-heptane conversion of 68.7%.Effects of the ion-exchange of Ce（III） and La（III） on the catalytic performance are discussed in relation with the physico-chemical properties of catalysts.展开更多
The structured lipids are produced through sn-l,3-specific interesterification of soybean oil with medium-chain triacylglycerol （MCT） in continuous reactions catalyzed by Thermomyces lanuginose lipase （Lipozyme TL...The structured lipids are produced through sn-l,3-specific interesterification of soybean oil with medium-chain triacylglycerol （MCT） in continuous reactions catalyzed by Thermomyces lanuginose lipase （Lipozyme TL IM）. Cheap Lipozyme TL IM presents similar interesterification degree （ID）, sn-l,3-specificity and residual activity as expensive Rhizomucor miehei in batch reactions. In packed-bed interesterification of soybean oil with Mcr cat- alyzed by Lipozyme TL IM, the residence time has a significant effect on ID, while temperature has a small effect at 45-70 ℃. The sn-l,3-specificity of Lipozyme TI. IM is not satisfactory when reaction temperature is higher than 60 ℃. The optimal residence time and temperature are 30-40 min and 55 ℃, respectively. Among the solvents, including acetone, isopropanol, tert-butanol, and isobutanol, used to recover the activity of the used Lipozyme TL IM, acetone is the most suitable one than the other solvents.展开更多
文摘There was heterogeneous distribution in stomatal conductance (g-s) and stomatal aperture for both high- and low-light leaves of Ligustrum sinense Lour. in four designated positions within a leaf. Linear or exponential or polynomial relationships between g-s and stomatal aperture were found when regression of g-s and stomatal aperture was established. Statistical analysis revealed that the relationship between g-s and stomatal aperture for high-light leaves was more significant than that of low-light leaves. A linear relationship between g-s and stomatal aperture existed in both positions 1 and 3 for both high- and low-light leaves. The stomatal density of the low-light leaves was much lower than that of the high-light leaves. The sensitivity of stomata to changing environment for high-light leaves was higher than that for low-light leaves, which may also relate to the higher stomatal density for the high-light leaves.
基金Supported by the Jiangsu Provincial Key Natural Science Foundation for Universities（06KJA53012） the National Natural Science Foundation of China（20476046 20976084）
文摘A series of Pt catalysts supported on the Hβ-zeolite that is ion-exchanged with the rare earth metal ions of Ce（III） and La（III）,are prepared by impregnation,characterized by inductively coupled plasma （ICP）,X-ray diffraction （XRD）,BET,temperature-programmed desorption of ammonia （NH3-TPD）,temperature-programmed reduction of hydrogen （H2-TPR） and H2-chemisorption techniques,and evaluated in the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor.The reaction temperature,time on stream,space velocity,and the ratio of H2/n-heptane are changed to get the optimal conditions.The Ce（III） and La（III）-exchanged Hβ-zeolites exhibit higher selectivity for isomerized products than the neat Hβ-zeolite.Moreover,the Ce（III）-exchanged catalysts give higher conversions of n-heptane,whereas the La（III）-exchanged ones do not show any improvement in con-version.Under optimal conditions,the catalyst with 0.4% （by mass） Pt and 0.5% （by mass） Ce loading presents very high selectivity of isomerized products of 95.1% coupled with high n-heptane conversion of 68.7%.Effects of the ion-exchange of Ce（III） and La（III） on the catalytic performance are discussed in relation with the physico-chemical properties of catalysts.
基金Supported by the National High Technology Research and Development Program of China(2010AA101505)the National Natural Science Foundation of China(21106013)
文摘The structured lipids are produced through sn-l,3-specific interesterification of soybean oil with medium-chain triacylglycerol （MCT） in continuous reactions catalyzed by Thermomyces lanuginose lipase （Lipozyme TL IM）. Cheap Lipozyme TL IM presents similar interesterification degree （ID）, sn-l,3-specificity and residual activity as expensive Rhizomucor miehei in batch reactions. In packed-bed interesterification of soybean oil with Mcr cat- alyzed by Lipozyme TL IM, the residence time has a significant effect on ID, while temperature has a small effect at 45-70 ℃. The sn-l,3-specificity of Lipozyme TI. IM is not satisfactory when reaction temperature is higher than 60 ℃. The optimal residence time and temperature are 30-40 min and 55 ℃, respectively. Among the solvents, including acetone, isopropanol, tert-butanol, and isobutanol, used to recover the activity of the used Lipozyme TL IM, acetone is the most suitable one than the other solvents.
