In order to explore the physiological and biochemical characteristics of fresh upper leaves and roots of different qualities of tobacco, the malonaldehyde （MDA）, superoxide dismutase （SOD） activity, chlorophyllase...In order to explore the physiological and biochemical characteristics of fresh upper leaves and roots of different qualities of tobacco, the malonaldehyde （MDA）, superoxide dismutase （SOD） activity, chlorophyllase activity, amylase activity, medium trace element content, chemical component content, root fresh weight, dry weight and activity in the normal tobacco leaves, tobacco leaves rich in nutrients and premature grey tobacco leaves were studied. The results showed that compared with the normal tobacco leaves, the root fresh weight, dry weight and activity in the premature grey tobacco leaves decreased by 41.22%, 14.44% and 60.29% respectively, while malonaldehyde content increased by 34.82%, and chlorophyllase, α-amylase, β-amylase and SOD activity declined by 89.55%, 65.71%, 71.26% and 37.25% respectively. Chlorophyllase, co-amylase and 13-amylase activity in the tobacco leaves rich in nutrients decreased by 58.76%, 36.19% and 41.93% respectively. The content of medium trace elements in the tobacco leaves rich in nutrients and premature grey tobacco leaves was lower than that of the normal tobacco leaves. Starch, total sugar, reducing sugar and potassium content in the normal tobacco leaves were higher than that of the tobacco leaves rich in nutrients and premature grey tobacco leaves.展开更多
Titania sol has been prepared by the sol-gel process with Ti（OC4H9）4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into th...Titania sol has been prepared by the sol-gel process with Ti（OC4H9）4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into the nanostructure TiO2. After TiO2 and rare earth doped TiO2 powders were calcined at 400℃, 500℃, 600℃, 700℃ and 800℃ respectively, the characteristic analyses of the TiO2 samples were studied by UV-VIS, XRD and TEM etc. It was found that there are some stringer absorption peaks at 200 - 325 nm. The rare earth doping can increase the phase transition temperature convertin8 anatase phase into rutile phase, can decrease the grain size of TiO2particles and can improve the ann-UV capacity of the coating fabrics.展开更多
The aim of this research was to find out whether the effect of chemical corrosion changes mechanical characteristics of surface layers of wooden construction elements. Degradation of the surface layers of wood was cau...The aim of this research was to find out whether the effect of chemical corrosion changes mechanical characteristics of surface layers of wooden construction elements. Degradation of the surface layers of wood was caused by chemical reactions of the basic substances of wood mass with compounds contained in antifire coatings. Fire retardants containing corrosive substances were often and repeatedly used in the Czech Republic on many wooden building constructions. This process of chemical corrosion is in practise called as ＂surface defibering of wood＂. This contribution presents standard and special experimental methods used for measuring the selected mechanical characteristics （compression strength, tension strength, bending strength, hardness and impact resistance） in the damaged surface layer of wooden construction elements. The material for experimental measuring was a construction element removed from a historical roof （ca 150 years old）. Mechanical characteristics of the surface layer of the defibered element were compared with the values measured in the deeper subsurface layer of non-damaged wood. The results of the experiments proved loss of cohesive strength and decrease of mechanical characteristics of wood only in a thin surface layer.展开更多
基金Supported by Science and Technology Project of Changsha Tobacco Company of Hunan Province(CYKJ2015-03)~~
文摘In order to explore the physiological and biochemical characteristics of fresh upper leaves and roots of different qualities of tobacco, the malonaldehyde （MDA）, superoxide dismutase （SOD） activity, chlorophyllase activity, amylase activity, medium trace element content, chemical component content, root fresh weight, dry weight and activity in the normal tobacco leaves, tobacco leaves rich in nutrients and premature grey tobacco leaves were studied. The results showed that compared with the normal tobacco leaves, the root fresh weight, dry weight and activity in the premature grey tobacco leaves decreased by 41.22%, 14.44% and 60.29% respectively, while malonaldehyde content increased by 34.82%, and chlorophyllase, α-amylase, β-amylase and SOD activity declined by 89.55%, 65.71%, 71.26% and 37.25% respectively. Chlorophyllase, co-amylase and 13-amylase activity in the tobacco leaves rich in nutrients decreased by 58.76%, 36.19% and 41.93% respectively. The content of medium trace elements in the tobacco leaves rich in nutrients and premature grey tobacco leaves was lower than that of the normal tobacco leaves. Starch, total sugar, reducing sugar and potassium content in the normal tobacco leaves were higher than that of the tobacco leaves rich in nutrients and premature grey tobacco leaves.
文摘Titania sol has been prepared by the sol-gel process with Ti（OC4H9）4, as precursor. TiO2 gel was obtained through hydrolysis and condensation process. Rare earth such as La2O3, CeO2 and Gd2O3 were introduced into the nanostructure TiO2. After TiO2 and rare earth doped TiO2 powders were calcined at 400℃, 500℃, 600℃, 700℃ and 800℃ respectively, the characteristic analyses of the TiO2 samples were studied by UV-VIS, XRD and TEM etc. It was found that there are some stringer absorption peaks at 200 - 325 nm. The rare earth doping can increase the phase transition temperature convertin8 anatase phase into rutile phase, can decrease the grain size of TiO2particles and can improve the ann-UV capacity of the coating fabrics.
文摘The aim of this research was to find out whether the effect of chemical corrosion changes mechanical characteristics of surface layers of wooden construction elements. Degradation of the surface layers of wood was caused by chemical reactions of the basic substances of wood mass with compounds contained in antifire coatings. Fire retardants containing corrosive substances were often and repeatedly used in the Czech Republic on many wooden building constructions. This process of chemical corrosion is in practise called as ＂surface defibering of wood＂. This contribution presents standard and special experimental methods used for measuring the selected mechanical characteristics （compression strength, tension strength, bending strength, hardness and impact resistance） in the damaged surface layer of wooden construction elements. The material for experimental measuring was a construction element removed from a historical roof （ca 150 years old）. Mechanical characteristics of the surface layer of the defibered element were compared with the values measured in the deeper subsurface layer of non-damaged wood. The results of the experiments proved loss of cohesive strength and decrease of mechanical characteristics of wood only in a thin surface layer.
