Nanosized TiO2 powder with anatase and rutile structures was synthesized by a sol gel method using TiCl4 ethanol solution as a precursor.The grain size ofTiO2 powder was about 63nm after the precursor was calcined at ...Nanosized TiO2 powder with anatase and rutile structures was synthesized by a sol gel method using TiCl4 ethanol solution as a precursor.The grain size ofTiO2 powder was about 63nm after the precursor was calcined at 600℃for 2 hours .The experimental techniques of XRD,TEM and Particle Distribution were used to characterize the synthesized specimens. Various special effects were investigated for their contribution to crystal structure and the size of TiO2 powder .Theformation of anatase as well as the rutile phase of TiO2 was indicted from the XRD when the reaction temperature was above 30℃and when the sol was irradiated by infrared rays .However, an anatase TiO2 powder formed after the heat treatment of the dried gel in a temperature range from 300℃to 500℃.Under the vacuum drying and with the calcined time below 3hours ,the anatase phase was gained .As well as with the increase of gelatinizing time, the anatase TiO2 powder was obtained.展开更多
This paper covers the preparation of a sol gel derived macrocyclic dioxopolyamine(1,4,7,10 tetraazaclotridecane 11,13 dione) stationary phase for open tubular capillary electrochromatography(OTCEC). The sol gel derive...This paper covers the preparation of a sol gel derived macrocyclic dioxopolyamine(1,4,7,10 tetraazaclotridecane 11,13 dione) stationary phase for open tubular capillary electrochromatography(OTCEC). The sol gel derived macrocyclic dioxopolyamine capillary columns have shown improved separations of neurotransmitters, isomeric nitrophenols, isomeric dihydroxybenzenes, isomeric aminophenols, isomeric diaminobenzenes and three ortho halogen anilines, in comparison with those of untreated capillaries. The characteristics of the sol gel derived macrocyclic dioxopolyamine capillary columns are compared with the capillary column modified with the macrocyclic dioxopolyamine by chemically bonded method after etching. The sol gel method provided a porous silica material with stationary phase in place within the same experimental procedure. This provided speedy fabrications of high efficiency columns with high surface area and improved phase ratio. We achieved high efficiencies of 60 000-340 000 plates/m for the various isomeric compounds. The reproducibility migration time and the plate number were pretty good.展开更多
文摘Nanosized TiO2 powder with anatase and rutile structures was synthesized by a sol gel method using TiCl4 ethanol solution as a precursor.The grain size ofTiO2 powder was about 63nm after the precursor was calcined at 600℃for 2 hours .The experimental techniques of XRD,TEM and Particle Distribution were used to characterize the synthesized specimens. Various special effects were investigated for their contribution to crystal structure and the size of TiO2 powder .Theformation of anatase as well as the rutile phase of TiO2 was indicted from the XRD when the reaction temperature was above 30℃and when the sol was irradiated by infrared rays .However, an anatase TiO2 powder formed after the heat treatment of the dried gel in a temperature range from 300℃to 500℃.Under the vacuum drying and with the calcined time below 3hours ,the anatase phase was gained .As well as with the increase of gelatinizing time, the anatase TiO2 powder was obtained.
文摘This paper covers the preparation of a sol gel derived macrocyclic dioxopolyamine(1,4,7,10 tetraazaclotridecane 11,13 dione) stationary phase for open tubular capillary electrochromatography(OTCEC). The sol gel derived macrocyclic dioxopolyamine capillary columns have shown improved separations of neurotransmitters, isomeric nitrophenols, isomeric dihydroxybenzenes, isomeric aminophenols, isomeric diaminobenzenes and three ortho halogen anilines, in comparison with those of untreated capillaries. The characteristics of the sol gel derived macrocyclic dioxopolyamine capillary columns are compared with the capillary column modified with the macrocyclic dioxopolyamine by chemically bonded method after etching. The sol gel method provided a porous silica material with stationary phase in place within the same experimental procedure. This provided speedy fabrications of high efficiency columns with high surface area and improved phase ratio. We achieved high efficiencies of 60 000-340 000 plates/m for the various isomeric compounds. The reproducibility migration time and the plate number were pretty good.
